Endograft Limb Occlusion in EVAR: Iliac Tortuosity Quantified by Three Different Indices on the Basis of Preoperative CTA

Predictive Factors for Iliac Limb Occlusions After Endovascular Abdominal Aneurysm Repair: Determined from Aortoiliac Anatomy, Endovascular Procedures, and Aneurysmal Remodeling

Purpose

Iliac limb occlusion (ILO) is a serious complication of endovascular abdominal aneurysm repair (EVAR). This study aimed to identify predictive factors for ILO derived from aortoiliac morphology, endovascular procedure-related parameters, and aneurysmal remodeling characteristics.

Patients and Methods

Patient demographics, pre-EVAR anatomical characteristics of the aneurysm, endovascular procedure details, and post-EVAR aneurysmal remodeling outcomes were analyzed and compared using univariate analysis. Statistically significant factors were subsequently subjected to Cox regression and Kaplan-Meier analyses.

Results

Between January 2013 and April 2022, 66 patients were included in this study. Fourteen patients presented with ILO and were compared with 52 control patients with patent endograft limb over at least 1-year of follow-up. The tortuosity indices of the common iliac artery (CIA) and endograft iliac limb to vessel oversizing were significantly larger in the ILO group than in the patent endograft limb group. The CIA index of tortuosity ≥1.08, and endograft iliac limb to vessel oversizing ≥18.8% were independent predictors for ILO. During the follow-up of all patients, the proximal aortic neck and CIA diameters increased, aneurysm sac diameter decreased, and aortic neck and aortic length increased. The aortoiliac length increased over time in patients with patent endograft limb but not in patients with ILO. A change in the lowest renal artery-left iliac bifurcation distance ≦0.07 mm increased the risk of ILO.

Conclusion

ILO is predisposed to occur when the CIA index of tortuosity ≥1.08 and endograft iliac limb to vessel oversizing ≥18.8% are present. Significant aortoiliac remodeling, including proximal aortic neck dilatation, neck straightening, aneurysmal sac regression, iliac artery enlargement, and aortic lengthening, occurs after EVAR. Aortoiliac elongation was observed in patients with patent endograft limb, but not in patients with ILO. ILO was associated with a change in the lowest renal artery-left iliac bifurcation from the postoperative measurements ≦ 0.07 mm.

Early Clinical Results From the Japanese Prospective Multicenter Study to Evaluate Zenith Alpha Abdominal Stent Graft for Abdominal Aortic Aneurysm (JUSTICE) Registry Demonstrate Acceptable Limb Patency at 12 Months

PURPOSE

Recent reports of the Zenith Alpha abdominal endovascular graft (Zenith Alpha AAA, Cook, Inc., Bloomington, Indiana) have demonstrated an unexpectedly high incidence of limb graft occlusion (LGO). The purpose of this study was to prospectively evaluate the performance of the Zenith AAA in Japan, with a specific focus on LGO.

MATERIALS AND METHODS

All endovascular aneurysm repairs (EVARs) for abdominal aortic aneurysms performed using the Zenith Alpha AAA from July 2020 to October 2021 in 23 Japanese hospitals were prospectively evaluated. All computed tomographic images were analyzed in the core laboratory. Late complications were defined as any aneurysm-related events occurring >30 days after EVAR, including aneurysm sac enlargement of >5 mm and any reinterventions performed. Endoleaks without sac enlargement or reintervention were excluded as late complications.

RESULTS

During the study period, 147 EVARs were performed using the Zenith Alpha AAA. The mean patient age was 76.5±7.7 years, 84.4% of patients were male, and the mean aneurysm diameter was 52.4±9.2 mm. Instruction-for-use violations were observed in 76 patients (51.7%), primarily associated with a severely angulated proximal neck (>60°). There were six intraoperative complications and 62 additional intraoperative treatments reported, most of which involved preemptive coil embolization of the inferior mesenteric artery (37 cases). Technical success, defined as the absence of type 1 or 3 endoleaks on final angiography, was achieved in 99.3% of patients. At 12 months, there was only one case of type 1/3 endoleak (0.8%) and one aneurysm sac enlargement exceeding 5 mm (0.8%); however, a high incidence of type 2 endoleaks was observed in 35.2% of patients, and aneurysm sac regression exceeding 5 mm was achieved in 30.1% of patients. Nine late complications were observed, and the rate of freedom from late complications at 12 months was 93.5%, encompassing four LGOs and one limb graft stenosis (3.4%).

CONCLUSIONS

In contrast to recent reports, our Japanese multicenter prospective study demonstrated satisfactory early clinical results, including an acceptable LGO rate, for the low-profile Zenith Alpha AAA. Long-term follow-ups will be performed to confirm the persistence of these outcomes.

CLINICAL IMPACT

This study prospectively evaluated the performance of 147 Zenith Alpha AAAs used for endovascular aneurysm repair with core-lab adjudication focusing especially on limb graft occlusion (LGO). At 12 months, aneurysm sac regression exceeding 5 mm was achieved in 30.1% of patients, and there was only one type 1/3 endoleak, one aneurysm sac enlargement (>5 mm), and nine late complications including five LGOs (3.4%), resulting in rate of freedom from late complications at 93.5%. Satisfactory early clinical results, including an acceptable rate of LGO can be achieved, particularly with cautious usage of the Zenith Alpha Spiral-Z Endovascular Leg." 5mm), and nine late complications including five LGOs (3.4%), resulting in rate of freedom from late complications at 93.5%. Satisfactory early clinical results, including an acceptable rate of LGO can be achieved, particularly with cautious usage of the Zenith Alpha Spiral-Z Endovascular Leg.

Impact of iliac access in elective and non-elective endovascular repair of abdominal aortic aneurysm

Endovascular aortic repair (EVAR) is nowadays the establishment treatment for patients with abdominal aortic aneurysm (AAA) both in elective and urgent setting. Despite the large applicability and satisfactory results, the presence of hostile iliac anatomy affects both technical and clinical success. This narrative review aimed to report the impact of iliac access and related adjunctive procedures in patients undergoing EVAR in elective and non-elective setting. Hostile iliac access can be defined in presence of narrowed, tortuous, calcified, or occluded iliac arteries. These iliac characteristics can be graded by the anatomic severity grade score to quantitatively assess anatomic complexity before undergoing treatment. Literature shows that iliac hostility has an impact on device navigability, insertion and perioperative and postoperative results. Overall, it has been correlated to higher rate of access issues, representing up to 30% of the first published EVAR experience. Recent innovations with low-profile endografts have reduced large-bore sheaths related issues. However, iliac-related complications still represent an issue, and several adjunctive endovascular and surgical strategies are nowadays available to overcome these complications during EVAR. In urgent settings iliac hostility can significantly impact on particular time sensitive procedures. Moreover, in case of severe hostility patients might be written off for EVAR repair might be inapplicable, exposing to higher mortality/morbidity risk in this urgent/emergent setting. In conclusion, an accurate anatomical evaluation of iliac arteries during preoperative planning, materials availability, and skilled preparation to face iliac-related issues are crucial to address these challenges.

Clinical Performance of the Low Profile Zenith Alpha Abdominal Endovascular Graft: 2 Year Results from the ZEPHYR Registry

OBJECTIVE

The midterm outcomes of the low profile Zenith Alpha Abdominal Endovascular Graft from the ZEnith alPHa for aneurYsm Repair (ZEPHYR) registry are reported.

METHODS

The ZEPHYR registry is a physician initiated, multicentre, non-randomised, core laboratory controlled, prospective registry. Inclusion criteria were patients with a non-ruptured abdominal aortic aneurysm with a maximum diameter ≥ 50 mm or enlargement > 5 mm within 6 months, with a site reported infrarenal neck length of ≥ 10 mm and with the intention to electively implant the Zenith Alpha abdominal endograft. Patients from 14 sites across Germany, Belgium, and the Netherlands were included. The primary endpoint was treatment success, defined as technical success and clinical success. Technical success was defined as successful delivery and deployment of the endograft in the planned position without unintentional coverage of internal iliac or renal arteries, with successful removal of the delivery system. Clinical success was defined as freedom from aneurysm sac expansion > 5 mm, type I or type III endoleaks, aneurysm rupture, stent graft migration > 10 mm, open conversion, and stent graft occlusion.

RESULTS

Three hundred and forty-seven patients were included in the ZEPHYR registry. The median clinical follow up was 743 days (interquartile range [IQR] 657, 806) with a median imaging follow up of 725 days (IQR 408, 788). Treatment success at 6 months, 1, and 2 years was 92.5%, 90.4%, and 85.3%, respectively. Freedom from secondary intervention was 94.3%, 93.4%, and 86.9%, respectively. The predominant reason for secondary intervention was limb complications. Freedom from limb occlusion (per patient) at 6 months, 1, and 2 years was 97.2%, 95.8%, and 92.5%, respectively. Univariable and multivariable Cox regression analyses could not identify any independent predictor for limb complications.

CONCLUSION

While treatment success is comparable with other commercially available grafts, the rate of limb complications at 2 years is of concern. The manufacturer's instructions for use should be followed closely. Further studies are necessary to investigate the root cause of the increased rate of limb complications with the Zenith Alpha Abdominal Endovascular Graft.

Novel Strategies for the Hostile Iliac Artery during Endovascular Aortic Aneurysm Repair

Successful endovascular aneurysm repair can be achieved with favorable aortic and iliac arterial anatomies. However, patients with challenging iliac anatomy, such as stenotic, calcified, tortuous arteries, or concomitant iliac artery aneurysms, are commonly encountered. Such a hostile iliac anatomy increases the risk of intraprocedural complications and worsens long-term outcomes. This review addresses various technical options for treating patients with a hostile iliac anatomy, including innovative endovascular solutions, physician-modified endografts, and hybrid procedures. These considerations demonstrate the wide scope of therapies that may be offered to patients with an unfavorable iliac anatomy.

Iliac tortuosity increases reinterventions but not adverse outcomes following repair of juxtarenal aneurysms using physician-modified endografts

OBJECTIVE

Increased angulation of the proximal aortic neck has been associated with complications following endovascular repair of infrarenal aortic aneurysms, including increased incidence of endoleaks, stent migration, secondary interventions, and conversions. However, knowledge on the impact of aortoiliac tortuosity on outcomes following fenestrated repair remains limited. This study aims to quantify the effect of aortoiliac tortuosity on outcomes following fenestrated repair.

METHODS

A single-center, retrospective review of all patients who underwent a physician-modified endovascular repair for the treatment of juxtarenal aortic aneurysms under a single physician-sponsored investigation device exemption study from 2011 to 2021 was performed. Center luminal lines and geometric distances were obtained using TeraRecon software (San Mateo, CA). A tortuosity index was calculated (tortuosity index = centerline distance/geometric line distance) for each iliac vessel as well as for the infrarenal aorta according to Society for Vascular Surgery reporting standards. Aortic and iliac tortuosity were assessed independently and stratified as low and high. Demographics, comorbidities, anatomic and operative details, and outcomes were compared using univariable and multivariable analysis.

RESULTS

A total of 135 patients were identified. Thirty-eight patients (28%) had high aortic tortuosity, and 55 patients (42%) had high iliac tortuosity. Patients with high tortuosity were older (aortic: 78 vs 76 years; P = .04; iliac: 78 vs 75 years; P = .01) and differed by sex. Twenty-two percent of men and 50% of women had high aortic tortuosity (P = .01). Forty-seven percent of men and 20% of women had high iliac tortuosity (P = .01). There were no differences in comorbidities based on aortic tortuosity, but coronary artery disease (high: 58% vs low: 36%; P = .01) and hypertension (high: 69% vs low: 86%; P = .02) differed based on iliac tortuosity. Aneurysm diameter was larger for patients with high iliac tortuosity (72 mm vs 64 mm; P < .01), and fluoroscopy time was longer for patients with high aortic tortuosity (41 vs 31 minutes; P = .02). When outcomes were assessed, high iliac tortuosity was associated with increased rate of reinterventions (hazard ratio, 2.6; 95% confidence interval, 1.2-6.0) and type 1 or 3 endoleak (hazard ratio, 5.2; 95% confidence interval, 1.7-16); however, all other outcomes were similar.

CONCLUSIONS

Among patients treated with physician-modified endovascular repair for juxtarenal aneurysms, iliac tortuosity but not aortic tortuosity, is associated with increased reinterventions and type 1 or type 3 endoleaks. Long-term follow-up is critical for patients with high iliac tortuosity to ensure that high-risk endoleaks are identified and treated early to avoid the risk of rupture.

Factors Related to Limb Occlusion After Endovascular Abdominal Aortic Aneurysm Repair (EVAR)

BACKGROUND

Limb occlusion is a potentially serious consequence of endovascular abdominal aortic aneurysm (EVAR). This case-control study identifies factors that predispose to limb occlusion.

METHODS

A consecutive series of patients from 2 centers undergoing EVAR over an 11-year period 2007-2017 were identified retrospectively. Patient records were interrogated allowing collations of demographics, intraoperative and perioperative data and surveillance data. The preoperative computed tomography angiogram was analyzed to determine EVAR relevant anatomical data. The primary outcome was occlusion of the iliac limb of the implanted EVAR. Raw data are presented as percentages, with comparative data analyzed using Mann-Whitney U-test and binomial logistic regression.

RESULTS

A total of 787 patients (702 males; median age 78 years, range 53-94 years old) were analyzed. Fifty patients reached the primary outcome, resulting in an overall limb occlusion rate of 6.35%. Factors predictive of limb occlusion were oversizing by >10% native vessel diameter, with oversizing of >20% in 50% of those that occluded. External iliac artery landing zone (12/50 limb occlusions) 24% and postoperative kinking (5/50 limb occlusions) 10% were also more common in those that occluded. Fifty randomly selected controls with similar baseline characteristics were studied. Oversizing of the iliac endograft was found to be significantly greater in the limb occlusion group compared to the controls (P < 0.001) which remained significant on regression analysis. There was no correlation with iliac tortuosity. The Cook stent graft had a 9% limb occlusion rate across sites. Medtronic and Vascutek endografts had 2.4% and 2.5% limb occlusion rates respectively.

CONCLUSIONS

Oversizing of iliac limbs by >20% could be a contributing factor to limb occlusion after EVAR and judicious oversizing should be used.

Editor's Choice -- European Society for Vascular Surgery (ESVS) 2024 Clinical Practice Guidelines on the Management of Abdominal Aorto-Iliac Artery Aneurysms

OBJECTIVE

The European Society for Vascular Surgery (ESVS) has developed clinical practice guidelines for the care of patients with aneurysms of the abdominal aorta and iliac arteries in succession to the 2011 and 2019 versions, with the aim of assisting physicians and patients in selecting the best management strategy.

METHODS

The guideline is based on scientific evidence completed with expert opinion on the matter. By summarising and evaluating the best available evidence, recommendations for the evaluation and treatment of patients have been formulated. The recommendations are graded according to a modified European Society of Cardiology grading system, where the strength (class) of each recommendation is graded from I to III and the letters A to C mark the level of evidence.

RESULTS

A total of 160 recommendations have been issued on the following topics: Service standards, including surgical volume and training; Epidemiology, diagnosis, and screening; Management of patients with small abdominal aortic aneurysm (AAA), including surveillance, cardiovascular risk reduction, and indication for repair; Elective AAA repair, including operative risk assessment, open and endovascular repair, and early complications; Ruptured and symptomatic AAA, including peri-operative management, such as permissive hypotension and use of aortic occlusion balloon, open and endovascular repair, and early complications, such as abdominal compartment syndrome and colonic ischaemia; Long term outcome and follow up after AAA repair, including graft infection, endoleaks and follow up routines; Management of complex AAA, including open and endovascular repair; Management of iliac artery aneurysm, including indication for repair and open and endovascular repair; and Miscellaneous aortic problems, including mycotic, inflammatory, and saccular aortic aneurysm. In addition, Shared decision making is being addressed, with supporting information for patients, and Unresolved issues are discussed.

CONCLUSION

The ESVS Clinical Practice Guidelines provide the most comprehensive, up to date, and unbiased advice to clinicians and patients on the management of abdominal aorto-iliac artery aneurysms.

Endovascular management of aortic aneurysm with severe neck angulation and/or iliac artery tortuosity using multiple stiff wire technique: a case series

Background

Suitable aortic neck is one of the essential components for thoracic endovascular aortic repair (TEVAR) and endovascular aortic repair (EVAR). Advanced techniques were developed to adjust and compromise the aneurysm neck angulation but with adding additional devices and complexity to the procedure. We proposed a simple technique to modify severe neck angulation and/or iliac artery tortuosity by using the multiple stiff wire (MSW) technique.

Method

Two femoral accesses were required for the MSW technique. A guidewire with a support catheter was inserted through the right and left femoral arteries and positioned in the abdominal or thoracic aorta. Wire exchanges were done with extra stiff wire in both femoral accesses. It can be considered to add multiple stiff wires to align the torturous neck / iliac artery. Delivery of the stent graft main body can be done via one of the accesses.

Result

Six patients with different aortic pathology were admitted to our hospital. Four patients undergo EVAR procedure and two patients undergo TEVAR procedure. All patients had aortic neck angulation problems with one patient having iliac artery tortuosity. MSW technique was performed on the patients with good results. Follow-up CTA after 3 months revealed a good stent position without stent migration and no endoleak was found in all but one patient.

Conclusion

MSW technique is a simple and effective technique to modify aortic neck/iliac artery angulation in TEVAR or EVAR procedure.

Stentgraft Limb Occlusion After Endovascular Aneurysm Repair: Incidence and Risk Factors

INTRODUCTION

Stentgraft limb occlusion (SLO) is a potential complication of endovascular aneurysm repair (EVAR). The purposes of this single centre study are to report the incidence of SLO after EVAR and to detect possible risk factors.

METHODS

All patients who underwent EVAR between June 2001 and February 2020 were included in this retrospective study. Demographic data, cardiovascular risk factors, aneurysm characteristics, arterial anatomy, repair strategy, systemic and stentgraft-related complications, and in-hospital and late mortality were collected. Routine follow-up included duplex examination and/or CT angiography at 3 months, 12 months and annually thereafter. Logistic regression analysis was performed to detect predictors for SLO.

RESULTS

A total of 221 patients (425 stentgraft limbs) were included; of whom 11 patients (5.0%) occluded. Median time to occlusion was 3.3 months and most of the patients presented ischemic signs. Two risk factors for SLO could be identified: symptomatic aneurysm (P .015, odds ratio 4.62, 95% confidence interval 1.35-15.86) and length of the infrarenal abdominal aortic aneurysm (AAA) (P .021, odds ratio 1.31, 95% confidence interval 1.04 - 1.64).

CONCLUSION

The incidence of SLO after EVAR is low, and most occlusions occur within the first year. Predictors for SLO are the symptomatic aneurysm and the length of the infrarenal AAA. Further research is necessary to pool all predictors and to assess the clinical impact of different follow-up strategies for high-vs low-risk patients.

Aneurysm Sac Shrinkage After EVAR Can Lead to Complications: A Case Report of Complete Endograft Thrombosis Due to Kinking

BACKGROUND

Bilateral limb occlusion after endovascular repair of abdominal aortic aneurysms (EVAR) is an uncommon entity. The relationship between graft kinking and unilateral limb occlusion is widely described in the literature. Our aim is to report a case of complete endograft thrombosis due to bilateral limb kinking secondary to aneurysm sac shrinkage, treated by endovascular means.

CASE REPORT

A 67 year-old male with history of EVAR with an Incraft® endograft (Cordis, Bridgewater, NJ, USA) four years before, presented at the emergency department with disabling claudication of the right lower extremity and a better tolerated 10-month left extremity claudication. Complete endograft thrombosis with bilateral limb kinking and a remarkable reduction of the aneurysm sac was observed in the computed tomography angiography. An endovascular repair was performed, through bilateral open femoral access and with angiographic control through percutaneous left brachial access. Bilateral recanalization was achieved and the endograft was re-lined with two 10x150 mm Viabahn (WL Gore & Ass., Flagstaff, AZ, USA). Both sides were extended with a 11 × 50 mm Viabahn (WL Gore & Ass., Flagstaff, AZ, USA). The final angiographic control showed bilateral patency with no residual stenosis and the patient recovered distal pulses. Follow-up showed complete patency and no complications at 17 months.

CONCLUSIONS

Bilateral limb occlusion is a rare complication with technically challenging treatment options. Aneurysm sac shrinkage can affect the endograft configuration, leading to limb distortion and occasionally to bilateral limb occlusion after EVAR. Special attention should be put on imaging follow-up to detect these complications before occlusion occurs.

Ultrasound Particle Image Velocimetry to Investigate Potential Hemodynamic Causes of Limb Thrombosis After Endovascular Aneurysm Repair With the Anaconda Device

PURPOSE

To identify potential hemodynamic predictors for limb thrombosis (LT) following endovascular aneurysm repair with the Anaconda endograft in a patient-specific phantom.

MATERIALS AND METHODS

A thin-walled flow phantom, based on a patient's aortic anatomy and treated with an Anaconda endograft, that presented with a left-sided LT was fabricated. Contrast-enhanced ultrasound particle image velocimetry was performed to quantify time-resolved velocity fields. Measurements were performed in the same phantom with and without the Anaconda endograft, to investigate the impact of the endograft on the local flow fields. Hemodynamic parameters, namely vector complexity (VC) and residence time (RT), were calculated for both iliac arteries.

RESULTS

In both limbs, the vector fields were mostly unidirectional during the peak systolic and end-systolic velocity phases before and after endograft placement. Local vortical structures and complex flow fields were observed at the diastolic and transitional flow phases. The average VC was higher (0.11) in the phantom with endograft, compared to the phantom without endograft (0.05). Notably, in both left and right iliac arteries, the anterior wall regions corresponded to a 2- and 4-fold increase in VC in the phantom with endograft, respectively. RT simulations showed values of 1.3 to 6 seconds in the phantom without endograft. A higher RT (up to 25 seconds) was observed in the phantom with endograft, in which the left iliac artery, with LT in follow-up, showed 2 fluid stasis regions.

CONCLUSION

This in vitro study shows that unfavorable hemodynamics were present mostly in the limb that thrombosed during follow-up, with the highest VC and longest RT. These parameters might be valuable in predicting the occurrence of LT in the future.

CLINICAL IMPACT

This in-vitro study aimed to identify potential hemodynamic predictors for limb thrombosis following EVAR using ultrasound particle image velocimetry (echoPIV) technique. It was shown that unfavorable hemodynamic norms were present mostly in the thrombosed limb. Owing to the in-vivo feasibility of the echoPIV, future efforts should focus on the evaluation of these hemodynamic norms in clinical trials. Thereafter, using echoPIV as a bedside technique in hospitals becomes more promising. Performing echoPIV in pre-op phase may provide valuable insights for surgeons to enhance treatment planning. EchoPIV is also applicable for follow-up sessions to evaluate treatment progress and avoid/predict complications.

Geometrical Changes of the Aorta as Predictors for Thromboembolic Events After EVAR With the Anaconda Stent-Graft

PURPOSE

Thromboembolic events (TE), including limb graft occlusion (LGO) and distal limb embolization (DLE), are common complications after endovascular aneurysm repair (EVAR). The aim of this study was to find predictors for TE in patients treated with the Anaconda stent-graft for infrarenal aneurysms.

MATERIALS AND METHODS

Geometrical and anatomical variables were retrospectively analyzed in a consecutive Anaconda cohort. Pre- and postoperative CT scans were used to derive geometrical parameters length, curvature, torsion, and tortuosity index (TI) from the center lumen lines (CLLs). Limb characteristics, pre-to-post EVAR and mid-term-follow-up changes in the parameters were evaluated for their predictive value for TE.

RESULTS

Eighty-four patients (mean age 74±8.3 years, 74 men) were enrolled. The risk of TE was lowered with pre-to-post implant decreasing TI (steps of 0.05: OR: 1.30, 95% CI: 1.01-1.66, p=0.04), pre-to-post implant decreasing mean curvature (OR: 1.08, 95% CI: 1.01-1.16, p=0.03), and a larger degree of circumferential common iliac artery (CIA) calcification (OR: 0.98, 95% CI: 0.97-1.00, p=0.03). The only LGO predictor was the caudal relocation of maximal curvature after EVAR (OR: 1.01, 95% CI: 1.00-1.01, p=0.04). Preventors of DLE were CIA diameter (OR: 0.87, 95% CI: 0.76-0.99, p=0.04), circumferential CIA calcification (OR: 0.97, 95% CI: 0.95-1.00, p=0.03), mean and maximal curvature of the preoperative aortoiliac trajectory (OR: 0.86, 95% CI: 0.79-0.94, p<0.01 and OR: 0.97, 95% CI: 0.95-1.00, p=0.03, respectively) and pre-to-postoperative decrease in mean curvature (OR: 1.11, 95% CI: 1.02-1.21, p=0.02). Midterm TE predictors were length (OR: 0.95, 95% CI: 0.89-1.01, p=0.08) and torsion maximum location (OR: 1.01, 95% CI: 0.99-1.01, p=0.10).

CONCLUSION

The present study confirms that treatment of infrarenal AAA with an Anaconda stent-graft is related to a relatively high TE rate which decreases with a pre-to-postoperative reduction in curvature and TI, and a larger degree of circumferential CIA calcification. In other words, more aortoiliac straightening and more circumferential CIA calcification may prevent TE development after EVAR with this stent-graft.

Association Between Aneurysm Wall Inflammation Detected by Imaging Perivascular Fat and Secondary Intervention Risk for Abdominal Aortic Aneurysm Patients After Endovascular Repair

OBJECTIVE

To investigate the association between the imaging biomarker (volumetric perivascular characterization index [VPCI]) which indicates the aortic wall inflammation by mapping the spatial changes of perivascular fat attenuation on computed tomography angiography (CTA) and the reintervention risk for abdominal aortic aneurysm (AAA) patients after endovascular aortic repair (EVAR).

METHODS

This case-control study included AAA patients undergoing EVAR from a single center (n=260). Cases were AAA patients undergoing reintervention after EVAR and a 1:1 frequency-matched control group of AAA patients post-EVAR with a shrunken or ≥3-year stable sac and free of reintervention signs during the follow-up. The predictive variable (VPCI trajectory) was converted to binary variables according to the changing trend of VPCI with follow-up time. As a quasi-complete separation data pattern, least absolute shrinkage and selection operator (lasso) regression was used to screen and prove the VPCI trajectory as the best predictor, and the performance was evaluated by calculating the accuracy, sensitivity, and specificity.

RESULTS

Between 2010 and 2021, 15 AAA patients after EVAR with type I/III endoleak, aneurysm rupture, or impending rupture were included. Compared with the 1:1 frequency-matched controls with a shrunken or ≥3-year stable sac and free of reintervention signs during the follow-up, VPCI trajectories of the case group were all upward trends, whereas the controls showed 86.7% downward trends (p<0.001). The best predictive model of lasso regressions included 4 variables, and VPCI trajectory was the most outstanding, followed by the proximal landing zone, the distal landing zone, and the infrarenal β angle. The accuracy, sensitivity, and specificity of predicting the risk of reintervention were as follows, respectively: 93.3%, 100%, and 86.7%.

CONCLUSIONS

The wall inflammation detected by imaging perivascular adipose tissue based on the CTAs was strongly associated with the reintervention risk for AAA patients after EVAR, which might hold major promise as a new imaging biomarker for the mechanism and treatment study of human AAAs before and after EVAR.

CLINICAL IMPACT

The study introduces a novel imaging biomarker which indicates the aortic wall inflammation by mapping spatial changes of perivascular fat attenuation on CTA. This biomarker demonstrates a strong association with the reintervention risk in AAA patients after EVAR. Incorporation of VPCI into clinical practice has the potential to enhance the traditional surveillance methods (CT/CTAs) by providing clinicians with a non-invasive method to assess aortic wall inflammation and predict the risk of reintervention. Additionally, this study might offer a valuable tool for mechanism and treatment research in humans with AAAs both pre- and post-EVAR, ultimately improving patient outcomes and refining therapeutic strategies.

Proximal Instructions for Use Violations in Elective Endovascular Aneurysm Repair in the Vascular Quality Initiative: Retrospective Analysis

BACKGROUND

Endovascular aneurysm repair (EVAR) is often attempted in patients with marginal anatomy. These patients' midterm outcomes are available in the Vascular Quality Initiative for analysis.

STUDY DESIGN

Retrospective analysis of prospectively collected data in the Vascular Quality Initiative from patients who underwent elective infrarenal EVAR between 2011 and 2018. Each EVAR was identified as either on- or off-instructions for use (IFU) based on aortic neck criteria. Multivariable logistic regression models were used to assess associations between aneurysm sac enlargement, reintervention, and type Ia endoleak with IFU status. Kaplan-Meier time-to-event models estimated reintervention, aneurysm sac enlargement, and overall survival.

RESULTS

We identified 5,488 patients with at least 1 follow-up recorded. Those treated off-IFU included 1,236 patients ([23%] mean follow-up 401 days) compared with 4,252 (77%) treated on-IFU (mean follow-up 406 days). There was no evidence of significant differences in crude 30-day survival (96% vs 97%; p = 0.28) or estimated 2-year survival (97% vs 97%; log-rank p = 0.28). Crude type Ia endoleak frequency was greater in patients treated off IFU (2% vs 1%; p = 0.03). Off-IFU EVAR was associated with type Ia endoleak on multivariable regression model (odds ratio 1.84 [95% CI 1.23 to 2.76]; p = 0.003). Patients treated off IFU vs on IFU experienced had increased risk of reintervention within 2 years (7% vs 5%; log-rank p = 0.02), a finding consistent with results from the Cox modeling (hazard ratio 1.38 [95% CI 1.06 to 1.81]; p = 0.02).

CONCLUSIONS

Patients treated off IFU were at greater risk for type Ia endoleak and reintervention, although they had similar 2-year survival compared with those treated on IFU. Patients with anatomy outside IFU should be considered for open surgery or complex endovascular repair to reduce the probability for revision.

Results of iliac branch devices for hypogastric salvage after previous aortic repair

OBJECTIVE

The aim of this multicentric study was to assess the "REsults of iliac branch deviceS for hypogastriC salvage after previoUs aortic rEpair (RESCUE)."

METHODS

All consecutive patients who underwent implantation of iliac branch devices (IBDs) after previous open aortic repair (OAR) or endovascular aortic repair (EVAR) at seven centers were captured. The study cohort was divided into two groups according to the type of repair originally performed. Early outcomes included immediate technical success and perioperative adverse events. Late outcomes included survival, side branch (SB) primary patency, SB instability, and new onset buttock claudication.

RESULTS

A total of 94 patients (82 male) were included in the study, 10 of them received bilateral implantation of IBDs. This resulted in a total of 104 devices included in the final analysis. Indication for treatment were endoleak 1b or progressive iliac aneurysmal degeneration or distal para-anastomotic aortic aneurysms; 73 were implanted after previous EVAR and 31 after previous OAR. Technical success was 100% in both groups. The 3-year rate of freedom from SB instability was 90.1% after previous EVAR and 85.4% after previous OAR, respectively (P = .05). The 3-year estimates of SB primary patency were significantly lower in patients who had received OAR as compared with those that had received EVAR (89.8% vs 94.9%; P = .05).

CONCLUSIONS

Endovascular treatment with IBDs following previous OAR or EVAR is safe and effective up to 3 years. Freedom from SB instability during follow-up was lower in patients who had previously undergone OAR than EVAR.

Early and Midterm Outcomes of Endovascular Aneurysm Repair With Zenith Alpha Abdominal Stent-Graft: Results From a Multicenter Retrospective Tuscany Registry

PURPOSE

Zenith Alpha Abdominal (Cook Medical, Bloomington, IN, USA) is one of the new-generation low-profile stent-grafts with demonstrated satisfactory early and midterm clinical outcomes for endovascular treatment of abdominal aortic aneurysms (AAAs). The aim was to evaluate early and midterm results of this device in the framework of a multicenter regional retrospective registry, with the analysis of morphological factors affecting outcomes, including different limb configurations.

MATERIALS AND METHODS

Between January 2016 and November 2021, 202 patients with AAA underwent elective endovascular aneurysm repair (EVAR) with implantation of a Zenith Alpha Abdominal in 7 centers. Early (30 day) outcomes in terms of technical and clinical success were assessed. Estimated 5 year outcomes were evaluated in terms of survival, freedom from type I/III endoleak, freedom from surgical conversion, freedom from limb graft occlusion, freedom from any device-related reintervention, and graft infection evaluation by life-table analysis (Kaplan-Meier test). A comparative analysis between different limb configurations (Zenith Spiral Z AAA iliac legs, codes ZISL vs ZSLE) was performed in terms of limb graft occlusion.

RESULTS

The 30 day technical and clinical success rates were 97.5% and 99.5%, respectively. Median follow-up period was 25.5 months (interquartile range [IQR]: 12-43.25). The 5 year survival rate was 73.6%. The estimated 5 year outcomes in terms of freedom from type I/III endoleak, freedom from surgical conversion, freedom from limb graft occlusion, freedom from any device-related reintervention, and freedom from graft infection were 88.6% (95% CI [confidence interval]: 83.4%-93.1%), 95.8% (95% CI: 92.7%-97.1%), 93.6% (95% CI: 90.2%-96.8%), 87% (95% CI: 83.3%-91.6%), and 97.7% (95% CI: 95.1%-98.9%), respectively. About limb configuration, no differences were found in terms of 5 year freedom from limb graft occlusion (ZSLE 93.4% [95% CI: 89.8%-95.5%] vs ZISL 94.3% [95% CI: 90.1%-95.9%], p=0.342; log-rank 0.903).

CONCLUSION

Zenith Alpha Abdominal in elective EVAR offered satisfactory early and 5 year outcomes with low complication rates. Limb graft occlusion continued to be an issue. Limb configuration did not affect outcomes.

CLINICAL IMPACT

The authors describe satisfactory early and 5 year outcomes of Zenith Alpha Abdominal in elective endovascular aortic repair in the framework of a multicenter regional retrospective registry. At 5 years freedom from type I endoleak was 88.6%, and rate of endograft infections and conversions to open repair were very low. in the present study. Hot topic about about Zenith stent-graft still remains the limb graft occlusion with a 30-day overall rate of 2%, and estimated 5-year freedom from limb graft occlusion of 93.6%. Limb graft configuration did not affect limb graft occlusion rate. A standardized protocol including iliac stenting should be adopted to reduce kimb graft occlusion.

A radiomics model for predicting the outcome of endovascular abdominal aortic aneurysm repair based on machine learning

OBJECTIVE

This study aimed to develop a radiomics model to predict the outcome of endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA), based on machine learning (ML) algorithms.

METHODS

We retrospectively reviewed 711 patients with infra-renal AAA who underwent elective EVAR procedures between January 2016 and December 2019 at our single center. The radiomics features of AAA were extracted using Pyradiomics. Pearson correlation analysis, analysis of variance (ANOVA), least absolute shrinkage, and selection operator (LASSO) regression were applied to determine the predictors for EVAR-related severe adverse events (SAEs). Eighty percent of patients were classified as the training set and the remaining 20 percent of patients were classified as the test set. The selected features were used to build a radiomics model in training set using different ML algorithms. The performance of each model was assessed using the area under the curve (AUC) from the receiver operating characteristic (ROC) curve in the test set.

RESULTS

A total of 493 patients were enrolled in this study, the mean follow-up time was 32 months. During the follow-up, 156 (31.6%) patients experienced EVAR-related SAEs. A total of 1223 radiomics features were extracted from each patient, of which 30 radiomics features were finally identified. The quantitative performance assessment and the ROC curves indicated that the logistics regression (LR) model had better predictive value than others, with accuracy, 0.86; AUC, 0.93; and F1 score, 0.91. The Rad-score waterfall plot showed that the overall amount of error was small both in the training set and in the test set. Calibration curve showed that the calibration degree of the training set and the test set were good (p > 0.05). Decision curve analysis (threshold 0.32) demonstrated that the model had good clinical applicability.

CONCLUSION

Our radiomics model could be used as an efficient and adjunctive tool to predict the outcome after EVAR.

Effects of Iliac Tortuosity Index on Fenestrated Endovascular Aortic Aneurysm Repair for Pararenal and Thoracoabdominal Aortic Aneurysms

PURPOSE

To evaluate the effect of iliac tortuosity on procedural metrics and outcomes of patients with complex aortic aneurysms (cAAs) undergoing repair with fenestrated/branched endografts (f/b-EVAR [endovascular aortic aneurysm repair]).

MATERIAL AND METHODS

The study is a single-center, retrospective review of a prospectively maintained database of patients undergoing aneurysm repair using f/b-EVAR between the years 2013 and 2020 at our institution. Included patients had at least 1 preoperative computed tomography angiography (CTA) available for analysis. Iliac artery tortuosity index (TI) was calculated using centerline of flow imaging from a 3-dimensional work station based on the formula: (centerline iliac artery length / straight-line iliac artery length). The associations between iliac artery tortuosity and procedural metrics, including total operative time, fluoroscopy time, radiation dose, contrast volume, and estimated blood loss (EBL), were evaluated.

RESULTS

During this period, 219 patients with cAAs underwent f/b-EVAR at our institution. Ninety-one patients (74% men; mean age = 75.2±7.7 years) met criteria for inclusion into the study. In this group, there were 72 (79%) juxtarenal or paravisceral aneurysms and 18 (20%) thoracoabdominal aortic aneurysms and 5 patients (5.4%) with failed previous EVAR. The average aneurysm diameter was 60.1±0.74 mm. Overall, 270 vessels were targeted, and 267 (99%) were successfully incorporated, including 25 celiac arteries, 67 superior mesenteric arteries, and 175 renal arteries. The mean total operative time was 236±83 minutes, fluoroscopy time was 87±39 minutes, contrast volume was 81±47 mL, radiation dose 3246±2207 mGy, and EBL was 290±409 mL. The average left and right TIs for all patients were 1.5±0.3 and 1.4±0.3, respectively. On multivariable analysis, the interval estimates suggest positive association between TI and procedural metrics to a certain degree.

CONCLUSIONS

In the current series, we found no definitive association between iliac artery TI and procedural metrics, including operative time, contrast used, EBL, fluoroscopy time, and dose in patients undergoing cAA repair using f/b-EVAR. However, there was a trend toward association between TI and all these metrics on multivariable analysis. This potential association needs to be evaluated in a larger series.

CLINICAL IMPACT

Iliac artery tortuosity should not exclude patients with complex aortic aneurysms from being offered fenestrated or branched stent graft repair. However, special considerations should be taken to mitigate the impact of access tortuosity on alignment of fenestrations with target vessels, including use of extra stiff wires, through and through access and delivering the fenestrated/branched device into another (larger) sheath such as a Gore DrySeal in patients with arteries large enough to accommodate such sheaths.

Iliac artery tortuosity index in Chinese patients with or without aortic artery aneurysms and related influencing factors

BACKGROUND

Iliac artery tortuosity is an important anatomical factor that influences the endovascular repair of aortic artery aneurysms (EVAR). The influencing factors of the iliac artery tortuosity index (TI) have not been well studied. TI of iliac arteries and related factors in Chinese patients with and without AAA were studied in this study.

SUBJECTS AND METHODS

One hundred and ten consecutive patients with AAA and 59 patients without AAA were included. For patients with AAA, the diameter of the AAA was 51.9 ± 13.3 mm (24.7-92.9 mm). Those without AAA had no history of definite arterial diseases and came from a cohort of patients diagnosed with urinary calculi. The central lines of the common iliac artery (CIA) and external iliac artery (EIA) were depicted. The actual length (L1) and the straight distance (L2) were measured and used to calculate the TI (L1/L2). Common demographic factors and anatomical parameters were analyzed to identify any related influencing factors.

RESULTS

For patients without AAA, the total TI of the left and right side was 1.16±0.14 and 1.16±0.13, respectively (p=0.48). For patients with AAAs, the total TI in the left and right side was 1.36±0.21 and 1.36±0.19, respectively (p=0.87). The TI in EIA was more severe than that in CIA both in patients with and without AAAs (p<0.01). Age was the only demographic factor found to be associated with TI in patients with AAA (Pearson's correlation coefficient r≈0.3, p<0.01) and without AAA (r≈0.6, p<0.01). For anatomical parameters, the diameter was positively associated with the total TI (left side: r=0.41, p<0.01; right side: r=0.34, p<0.01). The ipsilateral CIA diameter was also associated with the TI (left side: r=0.37, p<0.01; right side: r=0.31, p<0.01). The length of the iliac arteries was not associated with age or AAA diameter. Reduction of the vertical distance of the iliac arteries may be a common underlying reason for age and AAA.

CONCLUSIONS

Tortuosity of the iliac arteries was probably an age-related problem in normal individuals. It was also positively correlated with the diameter of the AAA and the ipsilateral CIA in patients with AAA. Attention should be paid to the evolution of iliac artery tortuosity and its influence when treating AAAs.

Limb graft occlusion after endovascular aneurysm repair with the Cook Zenith Alpha abdominal graft

OBJECTIVE

Prior reports of the low profile Zenith Alpha abdominal graft (Cook Medical Inc, Bloomington, IN) have shown impaired limb graft patency to be the primary causes of reintervention. Special notices from the manufacturer have indicated certain instructions for use (IFU) violations as the main reasons for these complications. In the present study, we assessed the incidence of limb graft occlusion (LGO) and analyzed the effects of the detailed anatomic risk factors for LGO highlighted in the IFU and previously reported studies.

METHODS

A retrospective study was performed of 241 patients treated with the low profile Zenith Alpha at a single institution from October 1, 2015 to September 30, 2018. All computed tomography angiograms were analyzed using three-dimensional software. Data were extracted from the electronic medical records until the end of the study period (December 31, 2020). The cumulative incidence of LGO and LGO-related reinterventions were assessed. A regression analysis was performed to evaluate the possible risk factors associated with the development of LGO at specified time points. These included aortic and iliac diameters, graft component oversizing, iliac tortuosity and calcification, overlap of graft components, proximal alignment of ipsilateral and contralateral legs, and sealing zone in the external iliac artery. Reader agreement of iliac calcification and tortuosity was assessed in patients with LGO.

RESULTS

A total of 33 limbs (7%) in 27 patients (11%) had become occluded. The cumulative incidence of LGO was 7% (95% confidence interval [CI], 5%-9%) per limb up to 3 years postoperatively. The previously described risk factors for LGO were studied using regression analysis; however, no positive association with LGO was identified. Heavily calcified common iliac arteries (CIAs) and external iliac arteries were protective against LGO compared with noncalcified vessels up to 3 years postoperatively (decreased risk, 17% [95% CI, -27% to -7%]; P = .001; and 15% [95% CI, -26 to -5]; P = .005, respectively). The reader agreement of iliac calcification and tortuosity showed substantial agreement (CIA intrareader kappa = 0.75; CIA interreader kappa = 0.62) and almost perfect agreement (intrareader kappa = 0.85; interreader kappa = 0.84), respectively.

CONCLUSIONS

The cumulative incidence of LGO after endovascular aneurysm repair with the Zenith Alpha graft was 7% per limb up to 3 years postoperatively. None of the analyzed risk factors suggested by the IFUs or current literature were positively associated with LGO.

High Thoracic Tortuosity Is Associated With CT-Markers of Degeneration of the Descending Thoracic Aortic Wall

Objective/Introduction

Increased vascular tortuosity may be an independent marker of generalized aortic pathology. This study investigates the association between descending thoracic aortic tortuosity, aneurysm pathophysiology, and outcomes following EVAR in AAA patients.

Methods

Patients who underwent elective EVAR between 2004 and 2018 were reviewed. Thoracic tortuosity index (TTI) was measured using 3D reconstruction software. Patients were dichotomized across the median TTI into high tortuosity [HT] (TTI >1.27, Figure1(a) ) and low tortuosity [LT] (TTI ≤1.27, Figure 1(b) ) groups. Perioperative complications, postoperative outcomes, and CT-based features of thoracic aortic wall degeneration ( Figure 1(c)-(e) ) were collected and analyzed.

Results

136 patients underwent treatment: 70 HT patients, including 54 males and 16 females (mean age: 77 years), and 66 LT patients, including 62 males and 4 females (mean age: 70 years) (age; P < .001). LT patients exhibited greater prevalence of hypercholesterolemia and diabetes (P = .045, P = .01). Presence of degenerative aortic wall markers was greater in HT patients (P = .045). HT patients had higher incidence of multiple aneurysms concurrently present in their aorta compared to LT (32.8% vs 11.3%; P = .002). Frequency of AAA rupture/dissection was 4.3% for HT and 1.5% for LT (P = .339). A trend was observed in all cause 30-day mortality in the HT group (P = .061). Other perioperative complications and postoperative outcomes were similar between groups.

Conclusion

High TTI was associated with older age at time of EVAR, greater prevalence of degenerative markers in the descending thoracic aortic wall, and widespread aorto-iliac dilation. While not predictive of EVAR outcomes, TTI can provide valuable information regarding aneurysm pathophysiology.

Effect of iliac tortuosity on outcomes after iliac branch procedures

OBJECTIVE

To report a two-centers evaluation of the effects of iliac axis tortuosity on iliac branch device (IBD) results.

METHODS

From 2015 to 2021, all IBD procedures performed at two European centers were analyzed retrospectively. The preoperative pelvic tortuosity index (PTI), external tortuosity index (ETI), and double iliac sign (DIS) were assessed for each iliac axis submitted to IBD. The primary endpoints were technical success, early and mid-term IBD complications (occlusion, stenosis, endoleaks [ELs]) and reinterventions, and the association with the PTI, ETI, and DIS. The 30-day mortality, survival, freedom from complications and freedom from reinterventions (FFR) were the secondary endpoints.

RESULTS

During the study period, 224 patients had undergone 256 IBD procedures for 165 (64.5%) aortoiliac aneurysms, 44 (17.2%) isolated iliac aneurysms, 11 (4.3%) abdominal aortic aneurysms with a short iliac landing zone, and 36 (14.1%) type Ib ELs. IBD was planned with endovascular aortic aneurysm repair for 158 (61.7%), fenestrated/branched endovascular aortic aneurysm repair for 45 (7.6%), and isolated for 53 (20.7%) cases. Technical success and 30-day mortality were 99.2% (254 of 256) and 0.9% (2 of 224), respectively. A PTI >1.4, an ETI >1.7, and the DIS were tested to identify the risk factors for the endpoints. No ELs and 9 (3.5%) IBD occlusions, requiring five reinterventions (2%), had occurred within 30 days. No association with the PTI, ETI, or DIS was identified; IBD oversizing of ≥25% on the external iliac artery was independently related to occlusion (odds ratio, 4.3; 95% confidence interval [CI], 1-18.1; P = .045). The mean follow-up was 31 ± 27 months, with 11 IBD occlusions, 14 ELs, and 21 reinterventions. At 1, 3, and 5 years of follow-up survival, IBD patency, and FFR were 95%, 89%, and 80%; 93%, 91%, and 90%; and 93%, 89%, and 83%, respectively. The risk factors for overall complications (n = 34; 13.3%) and reinterventions (n = 26; 10.2%) were an ETI >1.7 (P = .037 and P = .019), a PTI >1.4 (P = .016 and P = .012), and a type Ib EL as the indication (P = .025 and P = .001), respectively. Cox regression confirmed PTI >1.4 as an independent predictor of overall complications and reinterventions (hazard ratio [HR], 2.3; 95% CI, 1.1-4.4; P = .018; and HR, 3 95% CI, 1.3-6.8; P = .018, respectively) and ETI >1.7 as an independent risk factor for ELs (HR 6; 95% CI, 2.1-17.5; P = .001). The freedom from complications and FFR were significantly lower with a PTI >1.4 at 3 years (73% vs 92% [log-rank P = .01] and 77% vs 93% [log-rank P = .001], respectively).

CONCLUSIONS

We found IBDs to be safe and effective in the treatment of aortoiliac aneurysms. Early complications are uncommon and related to endograft oversizing rather than anatomic characteristics in the present study. Iliac tortuosity is a risk factor for overall complications and reinterventions, in particular for IBD-related ELs.

The effect of percutaneouS vs. cutdoWn accEss in patients after Endovascular aorTic repair (SWEET): Study protocol for a single-blind, single-center, randomized controlled trial

Background

Endovascular abdominal aortic repair (EVAR) and thoracic endovascular aortic repair (TEVAR) have become the first-line treatment for aortic diseases, but current evidence is uncertain regarding whether a percutaneous approach has better outcomes than cutdown access, especially for patient-centered outcomes (PCOs). This study is designed to compare these outcomes of percutaneous access vs. cutdown access after endovascular aortic repair.

Method

The SWEET study is a randomized, controlled, single-blind, single-center non-inferiority trial with two parallel groups in two cohorts respectively. After eligibility screening, subjects who meet the inclusion criteria will be divided into Cohort EVAR or Cohort TEVAR according to clinic interviews. And then participants in two cohorts will be randomly allocated to either intervention groups receiving percutaneous access endovascular repair or controlled groups receiving cutdown access endovascular repair separately. Primary clinician-reported outcome (ClinRO) is access-related complication, and primary patient-centered outcome (PCO) is time back to normal life. Follow-up will be conducted at 2 weeks, 1 month, 3 months postoperatively.

Discussion

The choice of either percutaneous or cutdown access may not greatly affect the success of EVAR or TEVAR procedures, but can influence the quality of life and patient-centered experience. Given the very low evidence for ClinROs and few data for PCOs, comparison of the percutaneous vs. cutdown access EVAR and TEVAR is essential for both patient-centered care and clinical decision making in endovascular aortic repair.

Trial registration

Chinese Clinical Trial Registry ChiCTR2100053161 (registered on 13th November, 2021).

Evaluation of electrocardiogram-gated computed tomography angiography to quantify changes in geometry and dynamic behavior of the iliac artery after placement of the Gore Excluder Iliac Branch Endoprosthesis

BACKGROUND

The GORE^® EXCLUDER^® Iliac Branch Endoprosthesis (IBE) is designed to treat iliac aneurysms with preservation of blood flow through the internal iliac artery (IIA). Little is known about the influence of IBE placement on the IIA geometry. This study aimed to provide detailed insights in the dynamic behavior and geometry of the common iliac artery (CIA) and IIA trajectory and how these are influenced after treatment with an IBE.

METHODS

Pre- and postoperative electrocardiogram-gated computed tomography angiography (ECG-gated CTA) scans were acquired in a prospective study design and analyzed with in-house written algorithms designed for aorto-iliac and endoprosthesis deformation evaluation. Cardiac pulsatility-induced motion patterns and pathlengths were computed by tracking predefined locations on the aorto-iliac tract. Centerlines through the CIA-IIA trajectory were used to investigate the static and dynamic geometry, including curvature, torsion, length and Tortuosity Index (TI).

RESULTS

Fourteen CIA-IIA trajectories were analyzed before and after IBE placement. Cardiac pulsatility-induced motion and pathlengths increased after IBE placement, especially at mid IIA and the first IIA bifurcation (P≤0.04). After IBE placement, static and dynamic curvature, length and TI decreased significantly (P<0.05). Furthermore, the average dynamic torsion increased significantly (P=0.030). The remaining geometrical outcomes were not statistically significant.

CONCLUSIONS

The placement of an IBE device stiffens and straightens the CIA-IIA trajectory. Its relation with clinical outcome is yet to be investigated, which can be done thoroughly with the ECG-gated CTA algorithms used in this study.

The Impact of Iliac Artery Anatomy on Distal Landing Zone After EVAR During the 12-Month Follow-Up

BACKGROUND

Proximal sealing zone has been the main interest in endovascular abdominal aortic aneurysm repair (EVAR), although the distal landing zone remodeling may also affect EVAR durability. The aim of this study was to assess iliac anatomy and its potential impact on distal landing zone adverse events after EVAR during the 12-month follow-up.

METHODS

A prospective data collection of patients treated with standard bifurcated EVAR devices for abdominal aortic aneurysm was undertaken between 2017 and 2019. Patients that received extension to the external iliac artery were excluded. Follow-up included computed tomography angiography (CTA) at the 1st and 12th month postoperatively. The common iliac artery (CIA) diameter was assessed in three levels: origin (just below the aortic bifurcation), distally (just above the iliac bifurcation) and the middle of the distance between these two landmarks. Iliac angle, tortuosity indexes, relining and oversizing were also analyzed. Distal landing zone-related adverse events were any limb related re-intervention, endoleak type Ib, graft migration, limb stenosis, or occlusion.

RESULTS

In total, 268 iliac limbs (134 patients) were included. In all three levels, the mean iliac artery diameters increased at 12-month follow-up. At the origin of the CIA, the diameter increased from 18.7 ± 10.5 mm to 19.9 ± 9.4 mm (P = 0.04), at the middle portion of the CIA, the diameter changed significantly from 15.5 ± 5.1 mm to 17.4 ± 5.4 mm (P < 0.001) and at the distal CIA, from 14.6 ± 3.3 mm to 15.1 ± 3.9 mm (P = 0.03). The iliac angle remained stable (P = 0.14) while the CIA index decreased significantly from 1.17 ± 0.13 to 1.11 ± 0.09 (P < 0.001). The mean value of oversizing was 21.5 ± 14.5% and affected distal iliac diameter increase (P < 0.001). The composite outcome of distal landing zone adverse events was not associated to diameter changes at any level. In 57 cases, a distal iliac diameter ≥18 mm was recorded. The estimated oversizing was lower (16.3 ± 11.8%) compared to <18 mm arteries (22.5 ± 14.9%, P = 0.01). At 12-month follow-up, iliac diameters remained stable in the ≥18 mm group. Endoleak type Ib was more common in iliac arteries ≥18 mm [3 (5.3%) vs. 1 (0.5%) (P = 0.04)] at 12-months.

CONCLUSIONS

Post-EVAR iliac artery dilation does not seem to have an impact on distal landing zone adverse events during the 12-month follow-up. Aggressive oversizing may be related to iliac dilation. EVAR patients with iliac arteries ≥18 mm are at higher risk for ET Ib.

Development and Comparison of Multimodal Models for Preoperative Prediction of Outcomes After Endovascular Aneurysm Repair

Objective

The aim of this study was to develop and compare multimodal models for predicting outcomes after endovascular abdominal aortic aneurysm repair (EVAR) based on morphological, deep learning (DL), and radiomic features.

Methods

We retrospectively reviewed 979 patients (January 2010—December 2019) with infrarenal abdominal aortic aneurysms (AAAs) who underwent elective EVAR procedures. A total of 486 patients (January 2010–December 2015) were used for morphological feature model development and optimization. Univariable and multivariable analyses were conducted to determine significant morphological features of EVAR-related severe adverse events (SAEs) and to build a morphological feature model based on different machine learning algorithms. Subsequently, to develop the morphological feature model more easily and better compare with other modal models, 340 patients of AAA with intraluminal thrombosis (ILT) were used for automatic segmentation of ILT based on deep convolutional neural networks (DCNNs). Notably, 493 patients (January 2016–December 2019) were used for the development and comparison of multimodal models (optimized morphological feature, DL, and radiomic models). Of note, 80% of patients were classified as the training set and 20% of patients were classified as the test set. The area under the curve (AUC) was used to evaluate the predictive abilities of different modal models.

Results

The mean age of the patients was 69.9 years, the mean follow-up was 54 months, and 307 (31.4%) patients experienced SAEs. Statistical analysis revealed that short neck, angulated neck, conical neck, ILT, ILT percentage ≥51.6%, luminal calcification, double iliac sign, and common iliac artery index ≥1.255 were associated with SAEs. The morphological feature model based on the support vector machine had a better predictive performance with an AUC of 0.76, an accuracy of 0.76, and an F1 score of 0.82. Our DCNN model achieved a mean intersection over union score of more than 90.78% for the segmentation of ILT and AAA aortic lumen. The multimodal model result showed that the radiomic model based on logistics regression had better predictive performance (AUC 0.93, accuracy 0.86, and F1 score 0.91) than the optimized morphological feature model (AUC 0.62, accuracy 0.69, and F1 score 0.81) and the DL model (AUC 0.82, accuracy 0.85, and F1 score 0.89).

Conclusion

The radiomic model has better predictive performance for patient status after EVAR. The morphological feature model and DL model have their own advantages and could also be used to predict outcomes after EVAR.

An observational assessment of Aortic Deformation During Infrarenal and Complex Endovascular Aortic Aneurysm Repair

OBJECTIVE

Real-time aortic deformation during endovascular aortic aneurysm repair (EVAR) has not been reported. Successful EVAR relies on predicting intraoperative aortic-endograft deformation from preoperative imaging. Correct prediction is essential, as malalignment of endografts decreases patient survival. We describe intraoperative aortic deformation during infrarenal endovascular aneurysm repair (EVAR) and complex fenestrated/branched EVAR (FEVAR/BEVAR), relating deformation to preoperative anatomy and follow-up outcomes.

METHODS

A multicentre retrospective cohort of aortic aneurysm patients undergoing operation January 2019- February 2021, substratified by repair, infrarenal EVAR (n=50), F/BEVAR, (n=80) and iliac branch graft with F/B/EVAR (IBG + F/B/EVAR, n=27), were compared using software-based non-rigid 2D/3D aortic deformational intraoperative assessment (CYDAR). Preoperative CT reconstructions of aortic and iliac tortuosities were assessed against intraoperative deformation, the primary outcome, and related to perioperative/follow-up adverse outcomes.

RESULTS

All treatment groups had low preoperative visceral aortic tortuosity; the EVAR group had higher iliac tortuosity (1.43 +/- .05; p=.018). Intraoperative aortic visceral deformation was consistently cranial and anterior; IBG + F/B/EVAR patients had the largest magnitude deformation (SMA: EVAR 5.1 +/- .9mm; F/BEVAR 4.4 +/- .4mm; IBG 8.3 +/- 1.2mm; p=.004). Celiac, SMA, and bilateral renal deformation was correlated (R=.923-.983). Iliac deformation was variable in magnitude and direction. Preoperative tortuosity was not correlated with the magnitude of intraoperative deformation nor was deformation magnitude related to endograft instability during follow-up, including endoleaks development, reinterventions, or visceral vessel complications.

CONCLUSIONS

The aorta deforms consistently during EVAR at the visceral aortic segment but un-predictably at the iliac bifurcation. Aortoiliac deformation is unrelated to adverse perioperative outcomes, branch instability, or reinterventions during short-term follow-up.

Fully automatic segmentation of abdominal aortic thrombus in pre-operative CTA images using deep convolutional neural networks

BACKGROUND

Endovascular aortic aneurysm repair (EVAR) is currently established as the first-line treatment for anatomically suitable abdominal aortic aneurysm (AAA).

OBJECTIVE

To establish a deep convolutional neural networks (DCNN) model for fully automatic segmentation intraluminal thrombosis (ILT) of abdominal aortic aneurysm (AAA) in pre-operative computed tomography angiography (CTA) images.

METHODS

We retrospectively reviewed 340 patients of AAA with ILT at our single center. The software ITKSNAP was used to draw AAA and ILT region of interests (ROIs), respectively. Image preprocessing and DCNN model build using MATLAB. Randomly divided, 80% of patients was classified as training set, 20% of patients was classified as test set. Accuracy, intersection over union (IOU), Boundary F1 (BF) Score were used to evaluate the predictive effect of the model.

RESULTS

By training in 34760-35652 CTA images (n= 204) and validation in 6968-7860 CTA images (n=68), the DCNN model achieved encouraging predictive performance in test set (n= 68, 6898 slices): Global accuracy 0.9988 ± 5.7735E-05, mean accuracy 0.9546 ± 0.0054, ILT IOU 0.8650 ± 0.0033, aortic lumen IOU 0.8595 ± 0.0085, ILT weighted IOU 0.9976 ± 0.0001, mean IOU 0.9078 ± 0.0029, mean BF Score 0.9829 ± 0.0011. Our DCNN model achieved a mean IOU of more than 90.78% for segmentation of ILT and aortic lumen. It provides a mean relative volume difference between automatic segmentation and ground truth (P> 0.05).

CONCLUSION

An end-to-end DCNN model could be used as an efficient and adjunctive tool for fully automatic segmentation of abdominal aortic thrombus in pre-operative CTA image.

Issues in Teaching Vascular Anatomy: Thoughts and Suggestions from the Clinician's Point of View

The role of anatomy in modern curricula is under reform due to competency of other rapidly evolving subjects and the rapid evolution of several practical aspects and applications dictating modernization of teaching methods as well as of teaching demands. Moreover, modern practice of medicine has put the arterial and vascular system in the center of numerous minimally invasive techniques. Therefore, regardless of their specialty, most doctors should have a very clear and precise knowledge of the vascular anatomy and the basic access techniques from the early years. This viewpoint commentary reflects the experience of the two authors in applying the principles and content of surgical vascular anatomy in undergraduate anatomy teaching and discusses the rationale of this. Moreover, it is suggested that cadaveric dissections should be modified with emphasis on standard surgical vascular exposures and the multidisciplinary teaching of vascular anatomy as a means not only to gain optimal long-term knowledge retention, but also to emphasize through realistic examples on the practical clinical value of vascular anatomy.

Incidence and predictive factors for endograft limb patency of the Fenestrated Anaconda™ endograft used for complex endovascular aneurysm repair

OBJECTIVE

To describe the incidence, risk factors and outcomes of treatment for limb occlusion in patients treated for complex (thoraco-)abdominal aortic aneurysms (AAA) with the Fenestrated Anaconda™.

METHODS

Between June 2010 and May 2018, 335 patients underwent elective fenestrated aortic aneurysm repair in 11 participating centers using the Fenestrated Anaconda™ with a median follow-up of 14.3 months (IQR 27.4). The primary outcome measure was freedom-from-limb-occlusion. Secondary outcome measures were freedom-from-limb-related-reintervention, secondary patency, and risk factors associated with limb occlusion.

RESULTS

Thirty (9.0%) patients presented with limb occlusion during follow-up with freedom-from-limb-occlusion of 98.5%, 91.2%, and 81.7% at 30-days, 1 and 5 years, respectively. In 87% of cases, no obvious cause for limb occlusion was documented. Primary occlusion occurred within 30-days in 36.7% and within 1 year in 80.0%. Twenty-three (6.9%) patients underwent an occlusion-related reintervention; seven (23.3%) patients were treated conservatively. Freedom-from-limb-occlusion-related-reintervention at 30-days, one and five years was 97.8%, 93.2% and 88.6%, respectively. Secondary patency was 91.3% after 1-month and 86.2% after 1 and 5 years, respectively. Female sex (OR 3.27 - 95% CI 1.28 to 8.34, P = .01) was a statistically significant predictor for limb occlusion. A higher percentage of thrombus in the aneurysm sac appeared to be protective for limb occlusion (0% compared to <25%: OR 0.22 - 95% CI 0.07 to 0.63, P = .01; 0% compared to 25-50%: OR 0.20 - 95% CI 0.07 to 0.57, P = .00 and 0% compared to >50%: OR 0.08 - 95% CI 0.02 to 0.38, P = .00), as did iliac angulation (OR 0.99 - 95% CI 0.98 to 1.00, P = .04).

CONCLUSION

Limb occlusion remains a significant impediment of endograft durability in patients treated with the Fenestrated Anaconda™, especially in female patients. Controversially, a high aneurysmal thrombus load and a high degree of iliac angulation appeared to be protective for limb occlusion, for which no obvious cause could be identified.

Impact of target visceral vessel anatomical configuration on early complications following endovascular repair of thoracoabdominal aortic aneurysms

Impact of target visceral vessel anatomical configuration on early complicatins following endovascular repair of thoracoabdominal aortic aneurysms Objectives: Fenestrated and branched endovascular aortic repair (fEVAR-bEVAR) is a viable treatment option for thoracoabdominal aortic aneurysms but target visceral stent (TVS) endoleak and thrombosis remain a limiting factor. This study aims to evaluate TVS anatomy impact on one-year risk of thrombosis and endoleak.

METHODS

Patients treated with fEVAR-bEVAR for thoracoabdominal aneurysms between 2008-2020 in our centre were enrolled. We recorded comorbidities, operative details, one-month postoperative CT scan (anatomical reference), and TVS behaviour: thrombosis and endoleak at one-year follow-up. For each TVS, different points were identified using a centre-lumen-line: (A) TVS origin, (B) end of branch/fenestration, (C) visceral vessel entry, (D) end of TVS, (E) 1-cm distally. We analyzed TVS tortuosity ((centre-lumen-line/straight distance)-1, in %), image vector analysis of each segment in 2D (antero-posterior, left-right) and 3D (craneo-caudal displacement), and centre-lumen-line analysis (bending in ABC and CDE). Three independent observers performed a blind analysis, and anatomical differences between bEVAR/fEVAR, and cases with/without 1-year thrombosis and TVS endoleak, were compared using Kaplan-Meier curves (Log-Rank test), and T-Test/Wilcoxon signed-ranks test respectively.

RESULTS

54 patients (72±713 years mean age; 182 TVS: 50 branches, 132 fenestrations) met the inclusion criteria. bEVAR cases had longer stents, with more caudal 3D angulation and greater ABC angulated segment. After excluding bEVAR cases (low case number), 97 fEVAR TVS were analyzed. Five thrombosis and seven endoleaks were observed. While anatomical configuration showed no association to thrombosis, it was related to endoleak: these cases presented more tortuous stents (5.97%±0.10, 21.40%±0,22, P=.011), with more angulated centre-lumen-line at ABC segment (5.69°±15.77°, 7.18°±7.77°, P=.012), and more upward-pointing stents in the origin of the stent (AB: 89.07°±24.46°, 109.09°±16.56°, P=.012; BC: 87.86°±21.10°, 113.11°±22.23°, P=.026).

CONCLUSIONS

Anatomical configuration of the TVS is associated with stent type I-III endoleak, but not thrombosis, at one-year following fEVAR. Cases with endoleak presented more tortuous stents, with a more angulated exit from the endograft and upward-pointing of the origin of the stent.

Application of the AngioJet Ultra Thrombectomy Device for the Percutaneous Mechanical Treatment (PMT) of Iliac Limb Occlusion after Endovascular Aneurysm Repair (EVAR)

BACKGROUND

To investigate the safety and efficacy of applying the AngioJet Ultra thrombectomy device in treating endograft occlusions in the iliac arteries following endovascular aneurysm repair (EVAR).

METHODS

This study utilized a retrospective analysis of 452 patients with infrarenal abdominal aortic aneurysm (AAA). Twelve of the patients experienced iliac limb occlusion during their follow-up period, and the AngioJet Ultra thrombectomy device was used in tandem with iliac angioplasty to treat these patients. The safety of the device was assessed through the amount of blood drawn, the duration of the procedure, and the occurrence of post-operative complications, while its efficacy was assessed through aortic computed tomography angiography (CTA) imaging and post-operative symptomatology results.

RESULTS

All 12 patients were male, and they had a mean age of 62.8 ± 11.8 years. Iliac limb occlusion occurred on the left side of 4 patients and on the right side of 8 patients. The AngioJet Ultra thrombectomy device was used together with iliac angioplasty during surgery, with a success rate of 100%. A bifurcated endograft was successfully implanted in 9 patients following AngioJet Ultra thrombectomy and balloon dilation angioplasty, while a unibody endograft was successfully implanted in 3 patients following AngioJet Ultra thrombectomy and balloon dilation angioplasty. The mean surgery duration was 2.4 hrs, and the patients were hospitalized for an average of 4.5 days. After surgery, the patients' intermittent claudication/buttock claudication gradually vanished. Two patients experienced hemoglobinuria, with one of them developing mild renal dysfunction. Currently, the twelve patients have been followed up for an average of 12 months, and none have experienced any lower extremity ischemia.

CONCLUSIONS

The use of the AngioJet Ultra thrombectomy device as a supplementary treatment for iliac limb occlusion following abdominal EVAR is safe, effective, and minimally invasive.

Endovascular recanalization and remodeling of abdominal aorta stent graft chronic total occlusion after failed extra-anatomic bypass surgery

OBJECTIVES

Chronic total occlusion (CTO) of the EVAR graft is a rare and serious complication. Traditionally, surgical intervention with prosthetic graft replacement or bypass graft implantation is performed. However, there are limited data in endovascular era.

METHODS

We present a case of a 68-year-old male with a history of late EVAR graft occlusion treated with multiple surgical interventions (femorofemoral crossover, extra-anatomic bypass surgery, and thrombectomy) five years ago. Color Doppler ultrasound (CDUS) and computed tomography (CT) angiography revealed thrombosis of the entire bypass graft. Endovascular recanalization and remodeling of the abdominal stent graft CTO was performed with a combination of bare stents and stent grafts. Rupture of the stent graft occurred on the right limb. A second covered stent was placed.

RESULTS

At 12-month follow-up, the patient was symptom free. Color Doppler ultrasound surveillance showed patent aortic stent graft and downstream arteries.

CONCLUSIONS

Endovascular recanalization of aortic stent graft CTO is a viable option in patients with failed bypass graft.

Limb Graft Occlusion Following Endovascular Aneurysm Repair for Infrarenal Abdominal Aortic Aneurysm with the Zenith Alpha, Excluder, and Endurant Devices: a Multicentre Cohort Study

OBJECTIVE

Limb graft occlusion (LGO) is a serious complication after endovascular aneurysm repair (EVAR) and while device development enables treatment of increasingly complex aortic anatomy, little is known about how endograft type affects the risk of occlusion. This observational study aimed to explore the incidence of LGO after EVAR for three major endograft systems.

METHODS

All patients with standard EVAR as the primary intervention for infrarenal abdominal aortic aneurysm (AAA), between January 2012 and December 2018, at five Swedish vascular surgery centres, were included in this multicentre retrospective cohort study. LGO was defined as a total limb occlusion regardless of symptoms, or a treated significant stenosis. A nested case control (NCC) design with incidence density sampling of 1:3 was used for analysis of potential per-operative and morphological risk factors. Conditional logistic regression was used to estimate multivariable odds ratios (OR) with 95% confidence intervals (CI) RESULTS: A total of 924 patients were included. The majority were male (84%), the mean age was 76 years (± 7.5 SD), and median AAA diameter was 59 mm (IQR 55, 67). Patients were treated with Zenith Alpha (n = 315, ZISL limbs), Excluder (n = 152, PLC/PXC limbs), and Endurant (n = 457, ETLW/ ETEW limbs). During median follow up of 37 months (IQR 21, 62), 55 occlusions occurred (5.9%); 39 with Zenith Alpha (12.4%), one with Excluder (0.7%), and 15 with Endurant (3.3%). In the NCC analysis, the Zenith Alpha device (OR 5.31, 95% CI 1.97 - 14.3), external iliac artery (EIA) landing (OR 5.91, 95% CI 1.30 - 26.7), and EIA diameter < 10 mm (OR 4.99, 95% CI 1.46 - 16.9) were associated with an increased risk of LGO.

CONCLUSION

Endograft device type is an independent risk factor for LGO after EVAR. Specifically, the Zenith Alpha demonstrated an increased risk of LGO compared with the Endurant and Excluder devices. In addition, a narrow EIA and landing zone in EIA are also risk factors for LGO.

One Year Outcomes of an International Multicentre Prospective Cohort Study on the Gore Excluder Iliac Branch Endoprosthesis for Aorto-Iliac Aneurysms

OBJECTIVE

The Gore Excluder Iliac Branch Endoprosthesis (IBE) was developed to preserve perfusion in the hypogastric artery after endovascular repair of aorto-iliac aneurysms. This study reports the 12 month technical and clinical outcomes of treatment with this device.

METHODS

This study was a physician initiated international multicentre, prospective cohort study. The primary endpoint was primary patency of the hypogastric branch at 12 months. Secondary endpoints included technical and clinical outcomes. Patients with an indication for elective treatment with the Gore Excluder IBE were enrolled between March 2015 and August 2018. Baseline and procedural characteristics, imaging data, physical examinations and questionnaire data (Walking Impairment Questionnaire [WIQ], EuroQol-5-Dimensions [EQ5D], International Index of Erectile Function 5 [IIEF-5]) were collected through 12 month follow up.

RESULTS

One hundred patients were enrolled of which 97% were male, with a median age of 70.0 years (interquartile range [IQR] 64.5 - 75.5 years). An abdominal aortic aneurysm (AAA) above threshold for treatment was found in 42.7% and in the remaining patients the iliac artery diameter was the indication for treatment. The maximum common iliac artery (CIA) diameter on the Gore Excluder IBE treated side was 35.5 mm (IQR 30.8 - 42.0) mm. Twenty-two patients received a bilateral and seven patients had an isolated IBE. Median procedural time was 151 minutes (IQR 117 - 193 minutes) with a median hospital stay of four days (IQR 3 - 5 days). Primary patency of the IBE at 12 month follow up was 91.3%. Primary patency for patients treated inside and outside the instructions for use were 91.8% and 85.7%, respectively (p = .059). Freedom from secondary interventions was 98% and 97% at 30 days and 12 months, respectively. CIA and AAA diameters decreased significantly through 12 months. IIEF-5 and EQ5D scores remained stable through follow up. Patency of the contralateral internal iliac artery led to better IIEF-5 outcomes. WIQ scores decreased at 30 days and returned to baseline values through 12 months.

CONCLUSION

Use of the Gore Excluder IBE for the treatment of aorto-iliac aneurysms shows a satisfactory primary patency through 12 months, with significant decrease of diameters, a low re-intervention rate, and favourable clinical outcomes.

Conformability of the GORE EXCLUDER iliac branch endoprosthesis is associated with freedom from adverse iliac events

OBJECTIVE

The GORE EXCLUDER iliac branch endoprosthesis (IBE; W.L. Gore & Associates, Flagstaff, Ariz) is designed to preserve internal iliac artery (IIA) patency during endovascular treatment of aneurysms involving the common iliac artery. The device is intended to conform to iliac tortuosity, which may decrease adverse iliac events (AIE). The objective of this study was to evaluate risk factors for AIE after IBE implantation.

METHODS

This was a post hoc analysis of the prospective, multicenter GORE 12-04 IBE pivotal trial. Patients with preoperative and postoperative axial imaging were included, with analysis based on each treated iliac system. An independent core laboratory performed all scan measurements, including iliac diameters, lengths, and tortuosity. Conformability was analyzed by the changes in tortuosity after IBE deployment, with less change indicating greater conformation. The end point was AIE, defined as ipsilateral radiographic or clinical complications. Critical nonconformation was defined as a threshold change in tortuosity associated with a significant increase in AIE.

RESULTS

We included 98 patients with 101 treated iliac systems. There were eight AIE (8%; six IIA component occlusions, one iliac branch component occlusion, and one EIA dissection requiring reintervention). Patients with AIE had smaller IIA diameters and less IBE conformability. After multivariable logistic regression analysis, an IIA diameter of less than 10 mm and a change in total iliac tortuosity beyond -15% were independently associated with AIE (odds ratio, 12 [interquartile range, 1.4-110] and odds ratio, 8.2 [interquartile range, 1.5-46], respectively), and the latter was used to define critical nonconformation. Critical nonconformation occurred in 11% of treated systems, and was associated with a high rate of AIE (36% vs 4%; P = .004).

CONCLUSIONS

Endograft conformation is a novel device property and technical outcome that, along with a larger IIA diameter, is associated with freedom from AIE after IBE deployment. An evaluation of these risk factors may better inform the management of patients with iliac aneurysmal disease. Further research on endograft conformation and patient outcomes is warranted, particularly for those with challenging anatomy undergoing complex procedures.

Effect of limb oversizing on the risk of type Ib endoleak in patients after endovascular aortic repair

OBJECTIVE

We assessed the association between the degree of limb oversizing and the risk of type Ib endoleak (TIBEL) in different types of iliac landing zones after endovascular aortic aneurysm repair.

METHODS

We performed a retrospective cohort study of patients who had undergone endovascular aortic aneurysm repair with bifurcated and limb endografts in an academic center. The main exposure was the degree of limb oversizing. The primary outcome was the occurrence of TIBELs. The secondary outcomes included limb occlusion, reintervention, and overall survival. Subgroup analyses stratified by ectatic and normal iliac landing zones were performed. Multivariate Cox regression analysis and sensitivity analyses using marginal structure model were conducted to adjust for potential confounders.

RESULTS

A total of 750 patients with 1500 iliac limb endografts were included in our study (817 limbs with oversizing of ≤10% and 683 with oversizing >10%). The median 1-year freedom from TIBEL was 98.9% (interquartile range [IQR], 98.0%-99.8%) for limbs with oversizing of ≤10% and 99.6% (IQR, 99.0%-100%) for limbs with oversizing >10%. The median 3-year freedom from TIBEL was 95.6% (IQR, 93.1%-98.1%) and 98.2% (IQR, 96.5%-99.9%) for oversizing ≤10% and >10%, respectively. We found that limb oversizing >10% was associated with a significantly decreased risk of TIBEL (adjusted hazard ratio [HR], 0.38; 95% confidence interval [CI], 0.19-0.76) in the overall population. After stratification by ectatic iliac landing zone, we found that limb oversizing >10% was associated with a significantly decreased risk of TIBEL in the ectatic iliac landing zones (adjusted HR, 0.38; 95% CI, 0.16-0.88). However, no significant difference was found in the limb endografts landing in normal iliac arteries (adjusted HR, 0.44; 95% CI, 0.13-1.45). In the subgroup of normal iliac arteries, we observed a significantly increased risk of limb occlusion in the limbs with distal oversizing >15% compared with the limbs with distal oversizing of ≤15% (adjusted HR, 4.66; 95% CI, 1.68-12.91).

CONCLUSIONS

Adequate limb oversizing >10% was associated with a significantly decreased risk of TIBEL in limbs with ectatic iliac landing zones. However, no additional benefit was observed for oversizing >10% in limb grafts landing in normal iliac arteries. Furthermore, excessive limb oversizing (>15%) in normal iliac landing zones can be associated with an increased risk of limb occlusion.

Editor's Choice - Mid Term Outcomes of Crossed Limb vs. Standard Limb Configuration in Endovascular Abdominal Aortic Aneurysm Repair: A Propensity Score Analysis

OBJECTIVE

The aim was to compare mid term outcomes between crossed limb (CL) and standard limb (SL) configuration in patients who underwent endovascular aortic aneurysm repair (EVAR).

METHODS

This was a comparative cohort study. Eligible patients who underwent EVAR between September 2011 and March 2019 in a tertiary academic centre were included. Inverse probability of treatment weighting (IPTW) was used to balance the demographic, anatomical and operative baseline characteristics between the two groups. The primary outcome was adverse limb events including type IB endoleak (T1BEL), type III endoleak, and limb occlusion. Cox proportional hazards regression and marginal structural model were performed to compare time to event outcomes.

RESULTS

The study included 729 patients (194 CL and 535 SL) with a median follow up of 34 months (interquartile range 16 - 62 months). The weighted analyses revealed no significant difference between CL and SL EVAR in terms of adverse limb events, type IA endoleak (T1AEL), type II endoleak (T2EL), re-intervention, and overall survival. In the subgroup analysis of large aneurysm sac, the CL configuration was associated with a significantly decreased risk of T1BEL (hazard ratio [HR] 0.31, 95% confidence interval [CI] 0.12 - 0.78, p = .014). Similar results were also observed in the subgroup of tortuous iliac arteries (HR 0.30, 95% CI 0.11 - 0.81, p = .017). After stratification by severe neck angulation, no significant difference was found between CL and SL EVAR for T1AEL, but the CL configuration was associated with a significantly increased risk of re-intervention (HR 2.69, 95% CI 1.31 - 5.51, p = .007). In addition, a trend towards a higher risk of adverse limb events in the CL group with severely angulated proximal neck was observed.

CONCLUSION

CL configuration in EVAR is safe and may be associated with a lower risk of T1BEL in patients with a large aneurysm sac or tortuous iliac arteries. However, it should be applied cautiously to aneurysms with a severely angulated neck due to the potentially higher risk of re-intervention.

Experience With Unfavorable Iliac Access When Performing Fenestrated/Branched Endovascular Aneurysm Repair

PURPOSE

To review a single-center experience with fenestrated and branched endovascular aneurysm repair (f/bEVAR) in patients with challenging iliac anatomies.

MATERIALS AND METHODS

A retrospective review of the department's database identified 398 consecutive patients who underwent complex endovascular repair f/bEVAR between January 2010 and June 2018; of these, 67 had challenging accesses. The strategies implemented to overcome access issues were reviewed, using a dedicated scoring system to evaluate the access (integrating diameter, tortuosity, calcification, and previous open or endovascular repair).

RESULTS

In this subgroup of patients, the most common graft design was a 4-vessel fenestrated endograft (27, 40.3%). Hostile access was due to small diameter (<7 mm) in 25 patients (37.3%) and/or concentric calcifications in 19 patients (26.9%). Mean iliac diameter was 5.5±2.6 mm on the right side and 6.0±2.5 mm on the left side. Previous open or endovascular aortoiliac repair had been performed in 15 patients (22.4%), and 20 patients (29.9%) had a stent previously implanted in at least 1 iliac artery, resulting in the inability to perform standard fenestrated repair with access from both sides. Five patients (7.5%) had a single patent iliac access. Eight distinctive strategies were identified to overcome these access issues, including the use of preloaded renal catheters in the endograft delivery system, angioplasty, graft modification (branches instead of fenestrations or 4 preloaded fenestrations), a conduit via a retroperitoneal approach, iliac artery recanalization, and/or the multiple puncture technique. Technical success was achieved in 62 cases (92.5%). Four patients had access complications and 1 died in the early postoperative period of multiorgan failure. Median follow-up was 24.6 months (IQR 7.2, 41.3). Clinical success at the end of follow-up was achieved in 57 patients (85.1%). During follow-up, 14 patients died, including 4 from an aorta-related cause.

CONCLUSION

Dedicated strategies can be implemented to overcome hostile iliac access in patients with complex aneurysms when f/bEVAR is required. Typically, these maneuvers are associated with favorable outcomes.

Early and midterm outcomes of endovascular aneurysm repair with an ultra-low-profile endograft from the Triveneto Incraft Registry

OBJECTIVE

We evaluated the early and midterm outcomes of the Incraft (Cordis Corp, Bridgewater, NJ) ultra-low-profile endograft by analyzing data from the Triveneto Incraft Registry (TIR).

METHODS

TIR is an independent multicenter cohort registry of 10 vascular surgery units in the Triveneto area (Northeast Italy). A prospective analysis of patients electively treated with Incraft from September 2014 to June 2019 was performed. The main outcomes were technical success, major 30-day complications, 30-day aneurysm-related death, freedom from reintervention, and mortality rate during follow-up and were analyzed using Kaplan-Meier curves. Univariable Cox regression was used to evaluate the associations between anatomic complexity factors and reintervention.

RESULTS

During the study period, 209 patients were included in the registry. Their mean age was 76.9 ± 7.7 years and the Society for Vascular Surgery comorbidity score was 0.97 ± 0.52. Most patients (n = 181; 86.6%) had presented with at least one complex anatomic factor: aortic neck angle α <135° in 31 patients (14.8%), conic neck in 17 patients (8.2%), iliac tortuosity index τ >1.5 in 102 (48.8%), iliac artery calcification >50% in 106 (50.7%), and external iliac artery <6 mm in 45 (21.5%). The concurrent presence of two or more complex iliac anatomic factors was present in 67 patients (32.1%). The technical success rate was 99.5%, and the early major complication rate was 1.5% (one limb occlusion, one iliac branch stenosis, one type III endoleak [EL]). No 30-day mortality was recorded. The mean follow-up period was 18.5 ± 13.2 months. The overall mortality was 9.5% (n = 18), none related to the aneurysm. The freedom from reintervention rate was 92.1%. Of these patients, six (3.2%) had been treated for type II EL embolization, one (0.5%) for type IA EL, four (2.1%) for iliac branch occlusion, and one (0.5%) for flow-limiting external iliac artery dissection. None of the single anatomic factors analyzed were predictive of reintervention. However, the association of two or more complex iliac anatomic factors was predictive of related reintervention (hazard ratio, 7.25; P = .014). The crude reintervention rate in this complex subgroup of patients was low (4 of 67; 6%).

CONCLUSIONS

Data from the TIR have demonstrated excellent early and midterm outcomes of endovascular aneurysm repair using the Incraft stent graft in patients with complex anatomy. The concurrent presence of two or more complex iliac anatomic factors still represent an issue for endovascular aneurysm repair success. However, the technical characteristics of this device resulted in low intervention rates, even for patients with these challenging issues.

The Efficacy of a Protocol of Iliac Artery and Limb Treatment During EVAR in Minimising Early and Late Iliac Occlusion

OBJECTIVE

Iliac limb occlusion (ILO) is a complication of endovascular aortic repair (EVAR) and requires re-intervention in most cases. Attention to any intra-operative defect of iliac limbs and arteries may prevent ILO. The study aimed to analyse the long term effect of an intra-operative protocol of iliac limb treatment during EVAR on ILO.

METHODS

Patients treated from 2012 to 2017 for abdominal aortic aneurysm (AAA) with standard EVAR were collected prospectively. Pre-operative computed tomography angiography anatomical characteristics were evaluated. The protocol for intra-operative iliac limb management was: a. pre-EVAR angioplasty of common/external iliac artery stenosis; b. precise contralateral iliac limb deployment at the same level of the flow divider; c. iliac limb kissing ballooning with high pressure non-compliant balloons; d. iliac limb stenting for residual tortuosity/kink and adjunctive external iliac stenting for residual stenosis/dissection after EVAR. ILO was evaluated at 30 days and at follow up, which was performed by duplex ultrasonography before discharge, at three, six, and 12 months and yearly thereafter. Kaplan-Meier and Cox linear regression were used.

RESULTS

Four hundred and forty-two patients and 884 iliac limbs were included in the study. Severe iliac tortuosity and calcification were present in 15% (132/884) and 8% (70/884), respectively. External iliac angioplasty and stenting of iliac limb were performed in 2% (18/884) and 9.5% (84/884) of limbs. The thirty day mortality was 1.6%, with no ILO. At a mean follow up of 33 ± 12 months, ILO occurred in 7/884 (0.8%) limbs of six patients. Five ILO were treated by endovascular relining, two surgically: one by femorofemoral bypass and one by surgical explant. On univariable analysis, sac shrinkage was significantly associated with ILO (HR 1, 95% CI 0.8-2.5, p = .043).

CONCLUSION

A protocol of aggressive iliac limb treatment in EVAR leads to a very low rate of late ILO. The role of sac shrinkage in ILO should be investigated further.

Endovascular Aneurysm Repair for Abdominal Aortic Aneurysm: A Comprehensive Review

Abdominal aortic aneurysm (AAA) can be defined as an abnormal, progressive dilatation of the abdominal aorta, carrying a substantial risk for fatal aneurysmal rupture. Endovascular aneurysmal repair (EVAR) for AAA is a minimally invasive endovascular procedure that involves the placement of a bifurcated or tubular stent-graft over the AAA to exclude the aneurysm from arterial circulation. In contrast to open surgical repair, EVAR only requires a stab incision, shorter procedure time, and early recovery. Although EVAR seems to be an attractive solution with many advantages for AAA repair, there are detailed requirements and many important aspects should be understood before the procedure. In this comprehensive review, fundamental information regarding AAA and EVAR is presented.

An Unusual Case of Delayed Complete Aortic Graft Occlusion Treated by Kissing Balloon Expandable Covered Stents and Renal Chimney

Introduction

Late occlusion of the entire stent graft after endovascular aortic repair (EVAR) is a rare condition which often requires open surgery. This is a case of endovascular rescue of chronic total occlusion of an aortic stent graft in a patient at high risk of open surgery and lysis.

Report

An 82 year old male was admitted with bilateral lower limb rest pain eight years after EVAR. Endovascular relining with a covered stent under local anaesthesia was planned. Antegrade recanalisation from brachial access was achieved, then VBX balloon expandable covered stents (W. L. Gore & Associates Inc. Flagstaff, AZ, USA) were deployed in a kissing configuration to reline the occluded stent graft, alongside a double renal chimney. The post-operative period was uneventful, and a six month CT angiogram confirmed the technical success with complete patency of the aorto-iliac segment and visceral arteries.

Discussion

Complete stent graft thrombosis after EVAR is typically managed by open conversion to aortobifemoral or axillobifemoral bypass graft, surgical thrombectomy or catheter directed thrombolysis, carrying a considerable mortality and morbidity rate. Endovascular relining with kissing covered balloon expandable stents with double renal chimneys is a less invasive option. By offering a unique combination of radial strength and flexibility, associated with a trackable delivery system and a high retention capability, the GORE VBX is the present authors’ preferred stent option for this procedure. The present case shows how endovascular recanalisation by antegrade and retrograde approaches may be an effective option, especially in a patient at high risk of open surgery and lysis.

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Late occlusion of the entire stent graft after EVAR is a rare condition.

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It is managed by conversion to aortobifemoral or axillobifemoral bypass.

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It can also be managed with surgical thrombectomy or catheter directed thrombolysis.

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Endovascular rescue is an option in patients at risk of open surgery and lysis.