Impact of Post-EVAR Graft Limb Kinking in EVAR Limb Occlusion: Aetiology, Early Diagnosis, and Management

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.

Computational Comparison of the Mechanical Behavior of Aortic Stent-Grafts Derived from Auxetic Unit Cells

PURPOSE

Inappropriate stent-graft (SG) flexibility has been frequently associated with endovascular aortic repair (EVAR) complications such as endoleaks, kinks, and SG migration, especially in tortuous arteries. Stents derived from auxetic unit cells have shown some potential to address these issues as they offer an optimum trade-off between radial stiffness and bending flexibility.

METHODS

In this study, we utilized an established finite element (FE)-based approach to replicate the mechanical response of a SG iliac limb derived from auxetic unit cells in a virtual tortuous iliac aneurysm using a combination of a 180° U-bend and intraluminal pressurization. This study aimed to compare the mechanical performance (flexibility and durability) of SG limbs derived from auxetic unit cells and two commercial SG limbs (Z-stented SG and circular-stented SG models) in a virtual tortuous iliac aneurysm. Maximal graft strain and maximum stress in stents were employed as criteria to estimate the durability of SGs, whereas the maximal luminal reduction rate and the bending stiffness were used to assess the flexibility of the SGs.

RESULTS

SG limbs derived from auxetic unit cells demonstrated low luminal reduction (range 4-12%) with no kink, in contrast to Z-stented SG, which had a kink in its central area alongside a high luminal reduction (44%).

CONCLUSIONS

SG limbs derived from auxetic unit cells show great promise for EVAR applications even at high angulations such as 180°, with acceptable levels of durability and flexibility.

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.

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.

Rotational Mechanical Thrombectomy to Treat Iliac Limb Occlusion after Endovascular Aortic Aneurysm Repair: The Rotational Mechanical Thrombectomy Italian Study

PURPOSE

To assess the safety and effectiveness of a rotational mechanical atherothrombectomy device in patients with symptomatic iliac limb occlusion after abdominal endovascular aneurysm repair (EVAR).

MATERIALS AND METHODS

A retrospective analysis was conducted on patients who underwent rotational mechanical thrombectomy using the Rotarex S device for symptomatic acute, subacute, or chronic graft limb thrombosis at 5 vascular centers between 2017 and 2021. This study comprised 23 male patients with a mean age of 74.5 years (SD ± 7.2) at the time of the procedure. The clinical presentation of the patients varied, with 1 patient experiencing acute limb ischemia and 11 patients (47.8%) experiencing disabling intermittent claudication. The remaining patients developed chronic limb-threatening ischemia after iliac limb occlusion. Early outcomes included technical success, postprocedural complications, and periprocedural mortality. Follow-up evaluations encompassed primary patency, patient survival, freedom from reintervention, and the need for surgical conversion.

RESULTS

Technical success was achieved in all cases, with no occurrences of distal embolization during or after the procedure, and no periprocedural deaths were reported. Endograft relining was performed in 82.6% of patients to establish a new, nonthrombogenic surface within the graft. Over a median follow-up period of 8 months (interquartile range, 3-16 months), 2 patients experienced iliac limb reocclusion. No deaths or other reinterventions occurred during the observational follow-up period.

CONCLUSIONS

Rotational mechanical thrombectomy for iliac limb occlusion after EVAR appears to be both safe and effective. This technique may uncover intraluminal defects contributing to graft occlusion and enable their resolution within the same procedure.

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.

A Retrospective Evaluation of Intra-Prosthetic Thrombus Formation After Endovascular Aortic Repair in Cook Zenith Alpha and Medtronic Endurant II Patients

OBJECTIVE

To investigate the occurrence of limb graft occlusion (LGO) and intra-prosthetic thrombus (IPT) formation in Zenith Alpha and Endurant II stent graft limbs.

METHODS

A single centre retrospective study was conducted on patients treated with the Zenith Alpha and Endurant II stent grafts between 2017 and 2019. All post-operative computed tomography angiography images were re-investigated for thrombus formation. Demographic, aneurysm, and stent graft data were collected and compared. LGO was defined as complete occlusion or significant stenosis (≥ 50% lumen diameter reduction). Logistic regression on pro-thrombotic risk factors was conducted. Freedom from LGO and overall limb IPT were compared using Kaplan-Meier analyses.

RESULTS

Seventy-eight Zenith Alpha and eighty-six Endurant II patients were studied. The median follow up was 33 (IQR 25, 44) months for Zenith Alpha patients and 36 (IQR 22, 46) months for Endurant II patients (p = .53). LGO was seen in 15% (n = 12) of Zenith Alpha patients and 5% (n = 4) of Endurant II patients (p = .032), and freedom from LGO was significantly higher among Endurant II patients (p = .024). The Zenith Alpha stent graft was an independent risk factor for LGO (OR 3.9, 95% CI 1.1 - 13.4; p = .032). Among Zenith Alpha patients, limb flare compression within the main body gate was over represented in LGO patients (p = .011). There was no difference in freedom from overall limb IPT between the stent graft systems. For Endurant II limbs, IPT was significantly less common in the integrated ipsilateral limbs (without ETLW/ETEW stent graft limbs) (p = .044). Main endograft body IPT was correlated with overall limb IPT (p = .035).

CONCLUSION

LGO was significantly more common among Zenith Alpha than Endurant II patients. Zenith Alpha limbs was an independent risk factor for LGO. There was no difference between stent grafts in overall limb IPT formation.

Penumbra Indigo Percutaneous Aspiration Thrombectomy System in the treatment of Aortic Endograft Iliac Limb Occlusion: Results from an Italian Multicentre Registry

OBJECTIVE

This study aimed to evaluate the safety and effectiveness of the Penumbra Indigo percutaneous aspiration thrombectomy (PAT) system in the clinical presentation of iliac limb occlusion (ILO) after endovascular aortic repair (EVAR).

METHODS

A retrospective, observational, multicentre study conducted in eight Italian vascular centres. Consecutive patients presenting with ILO after EVAR were eligible. To assess vessel revascularisation, Thrombo-aspiration In Peripheral Ischaemia (TIPI) classification (score 0-3) was used at presentation (t1), after PAT (t2), and after adjunctive procedures (t3). Successful revascularisation was considered TIPI 2-3 (near complete or complete). Primary intra-operative outcomes were technical success (TS) of Indigo PAT and combined TS of PAT associated with adjunctive procedures when needed. Primary follow up outcomes were safety and effectiveness at one, six, and 12 months.

RESULTS

From September 2019 to December 2021, there were 48 ILO and 17 patients (35%) [median age 75 years, IQR 71, 83 years; male, 14 (82%); urgent, 8 (47%)] were treated and enrolled. The median time after primary EVAR was 24 months (IQR 0, 42 months). The median clot age from ILO diagnosis to PAT was three days (IQR 1, 12 days). Ten patients (59%) presented with limb threatening ischaemia. At t1, TIPI 0 and 1 was present in 13 (76%) and four (24%) cases, respectively. At t2, primary TS (TIPI 2-3) was achieved in 14 cases (82%) after Indigo PAT (p < .001). Fifteen patients (88%) required adjunctive procedures (14 re-linings, one surgical patch angioplasty). At t3, combined TS was achieved in 16 cases (94%). Intra-operative complication included one (6%) distal embolisation, treated successfully. The 30 day mortality was one case (6%) due to pneumonia. At one, six, and 12 months, clinical success was 100% without ILO recurrence. The median follow up was 23 months (IQR 11, 41 months): at 18 months, survival and freedom from re-intervention were 91 ± 8% and 90 ± 9%, respectively.

CONCLUSION

This study reports for the first time the efficacy and safety of Penumbra Indigo PAT for ILO after EVAR, with promising technical and clinical success up to one year.

Intraoperative complications during standard and complex endovascular aortic repair

This study aimed to provide a comprehensive overview of the most common intraoperative adverse events that occur during standard endovascular repair and fenestrated-branched endovascular repair to treat abdominal aortic aneurysms, thoracoabdominal aortic aneurysms, and aortic arch aneurysms. Despite advancements in endovascular techniques, sophisticated imaging and improved graft designs, intraoperative difficulties still occur, even in highly standardized procedures and high-volume centers. This study emphasized that with the increased adoption and complexity of endovascular aortic procedures, strategies to minimize intraoperative adverse events should be protocolized and standardized. There is a need for robust evidence on this topic, which could potentially optimize treatment outcomes and durability of the available techniques.

Presentation and management of delayed aortic endograft infection

A man in his 60s who underwent endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm 4 years ago presents with 1 week of abdominal pain, fever and leucocytosis. CT angiogram demonstrated an enlarged aneurysm sac with intraluminal gas and periaortic stranding consistent with infected EVAR. He was clinically unfit for an open surgical intervention due to his significant cardiac comorbidities, including hypertension, dyslipidaemia, type 2 diabetes, recent coronary artery bypass grafting and congestive heart failure secondary to ischaemic cardiomyopathy with an ejection fraction of 30%. Therefore, due to this significant surgical risk, he was treated with percutaneous drainage for the aortic collection and lifelong antibiotics. The patient is well 8 months following presentation with no signs of ongoing endograft infection, residual aneurysm sac enlargement, endoleak or haemodynamic instability.

Evaluation of factors associated with limb thrombus formation after endovascular aortic aneurysm repair

BACKGROUND

Limb thrombus formation is a complication that can occur after endovascular aortic repair (EVAR), and its clinical significance has continued to be debated. Our objective was to report the incidence of limb thrombus after EVAR and determine the association of specific demographic, anatomic, and/or graft variables.

METHODS

A retrospective analysis of EVAR patients at a single tertiary center between January 2010 and December 2018 was performed to determine the limb thrombus rate. Demographic, graft, and anatomic variables were analyzed for an association with limb thrombus.

RESULTS

A total of 301 patients were included. The average follow-up was 27.6 ± 4.9 months. The mean age was 76.5 ± 0.5 years, and 85% were men. Limb thrombus occurred in 22 patients (7.3%). Of these 22 patients, 11 (50.0%) had had occlusive limb thrombus, 14 (63.6%) were symptomatic, and 17 (77.3%) had required intervention. The patients with limb thrombus were younger (69.8 ± 1.3 years vs 77.1 ± 0.5 years; P < .0001) and more likely to be smokers (10.2% vs 5.2%; P = .10). The incidence of limb thrombus with the Alpha graft (10.7%; Cook Medical Inc, Bloomington, IN) was compared with that with non-Cook grafts (4.0%; P = .07). The average common iliac artery diameter for patients with and without limb thrombus was 14.1 mm and 16.1 mm, respectively (P < .01). Right-sided limb thrombus was more likely in smaller right iliac arteries (14.7 ± 0.9 cm vs 17.0 ± 0.6 cm; P < .05), with a similar finding on the left (13.6 ± 0.9 cm vs 15.2 ± 0.4 cm; P = .13). Unilateral limb thrombus was almost twice as likely on the main body side than on the contralateral side (11 vs 6). Limb thrombus was not associated with aortoiliac disease (odds ratio [OR], 1.31; 95% confidence interval [CI], 0.37-4.62), limb extension (OR, 0.47; 95% CI, 0.06-3.62), or nonmatching limb heights (OR, 1.36; 95% CI, 0.54-3.43). Limb thrombus was also not associated with increased 30-day mortality (P > .05).

CONCLUSIONS

Limb thrombus formation is a complication that can occur after EVAR (7.3%). In our study, limb thrombus was seen more frequently in younger patients and those who smoked. Cook Alpha grafts had a thrombus formation rate of 10.7%, which was not significantly higher than that with other brands. Limb thrombus was more likely in smaller iliac arteries and on the main body side.

Low-Profile Altura Endograft System for Endovascular Abdominal Aorta Aneurysm Repair. Preliminary Results in Elective and Emergent Situations

BACKGROUND

The objective of this study was to assess the Altura endoprosthesis outcomes up to 12 months for patients affected by infrarenal abdominal aortic aneurysms (AAA) either in elective or emergent situations.

METHODS

This was a single-center retrospective study identifying all patients undergoing endovascular aneurysm repair (EVAR) with the Altura endoprosthesis from January 2021 to August 2022. Outcomes evaluated included mortality, technical and clinical success (freedom from procedure-related death, endoleak, migration, thrombosis, and reintervention), and the freedom from reintervention rate.

RESULTS

A total of 34 (25 elective and 8 emergent) patients who underwent AAA with Altura endoprosthesis were retrospectively reviewed. The technical success of the Altura endograft either in elective or emergent situations was 100%. There was no inhospital mortality, but 1 (3%) patient who underwent AAA repair emergently, died unexpectedly 7 days after the discharge due to massive pulmonary embolism. The clinical success and the freedom from reintervention during the median follow-up of 12 months (interquartile range [IQR] 12-18), were 97%. One patient presented with disabling intermittent claudication at third month postoperatively, and the computed tomographic angiography (CTA) revealed thrombosis of one of the iliac endografts (3%). The patient underwent femorofemoral bypass with an uneventful postoperative course and immediate relief of the symptoms. One type II endoleak was spontaneously resolved on the sixth month. Sac shrinkage (>3 mm) was registered in 12 patients (35%), but the sac size was stable in the remaining 22 (65%) patients.

CONCLUSIONS

The preliminary outcomes of the Altura endograft seem to be promising, suggesting that the endograft could be safely used either in elective or emergent situations. Further studies with a major number of participants are needed to document its technical and clinical performance, especially in emergency situations that could be amenable to improvement.

Acute occlusion of aortic endovascular aneurysm repair stent graft with bilateral limb ischemia

Endovascular aneurysm repair has dramatically changed the management of abdominal aortic aneurysms as an alternative to open repair. However, complications can occur, including stent graft migration, kinking, and occlusion, leading to compromise of the excluded aneurysm walls and acute limb ischemia. In the present report, we have described a case of migration and kinking of an abdominal aortic stent graft in the main body that led to occlusion of the abdominal aorta and bilateral acute limb ischemia. The patient required emergent explantation of the stent graft and open repair of the abdominal aneurysm with a rifampin-soaked Dacron graft, which achieved a favorable outcome.

Artificial intelligence's role in vascular surgery decision-making

Artificial intelligence (AI) is the next great advance informing medical science. Several disciplines, including vascular surgery, use AI-based decision-making tools to improve clinical performance. Although applied widely, AI functions best when confronted with voluminous, accurate data. Consistent, predictable analytic technique selection also challenges researchers. This article contextualizes AI analyses within evidence-based medicine, focusing on "big data" and health services research, as well as discussing opportunities to improve data collection and realize AI's promise.

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.

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.

Limb Occlusion Rate after EVAR With Individualized Graft Limb Selection and a Liberal Protocol of Primary Relining

BACKGROUND

This study analyses limb occlusion rates after endovascular aneurysm repair (EVAR) with a strategy including stent-graft limb selection and liberal primary stenting (relining) in anatomies at higher risk for occlusion with uncovered self-expandable or balloon-expandable stents.

METHODS

All patients undergoing elective EVAR with a bifurcated stent-graft between January 2010-August 2018 were included. A protocol involving personalized stent-graft selection and liberal primary relining based on preoperative imaging was followed during the whole period. Primary endpoints were technical success and primary limb patency during follow-up. Secondary endpoints included mortality and limb reintervention rates. Risk factors associated to limb patency and reintervention rates were analyzed.

RESULTS

Six hundred and fifteen patients (548 males; mean age 72.9 ± 9 years) were included. Overall technical success was 98.5% (606/615). One (0.16%) patient died during the first 30 days. Of the 1230 limbs, 96 (8%) were deemed at risk for occlusion in view of the anatomy, and primarily relined in 62 patients. Estimated primary limb patency at 6 months, 1 year and 3 years was 99.5 ± 0.2%, 99.2 ± 0.3% and 98.5 ± 0.5%, respectively. Freedom from limb-related reintervention at 6 months, 1 year and 3 years was 98.1 ± 0.4%, 97.4 ± 0.5% and 95.6 ± 0.7%, respectively. Only one (1%) of the 96 relined limbs occluded during follow-up. No differences were found in terms of patency or freedom from reintervention between limbs at risk that were primary stented and limbs without adjunctive stents. Gore Excluder stent-grafts presented better patency (Breslow P = 0.005) and lower reintervention rates (Breslow P = 0.001) than other devices during follow-up. Peripheral artery disease was also a risk factor for reintervention (Breslow P = 0.015).

CONCLUSION

Liberal use of primary limb relining in patients with iliac anatomy at higher risk for occlusion appears to be a safe and effective strategy to preserve limb patency after EVAR. Gore Excluder graft limbs present better patency and lower reintervention rates than other stent-graft types.

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.

Secondary Interventions and Long-term Follow-up after Endovascular Abdominal Aortic Aneurysm Repair

BACKGROUND

Early morbidity and mortality are low after endovascular abdominal aneurysm repair (EVAR), but secondary interventions and late complications are common. The aim of the present multicenter cohort study is to detail the frequency and indication for interventions after EVAR and the impact on long-term survival.

METHODS

A retrospective multicenter cohort study of secondary interventions after elective EVAR for an infrarenal abdominal aortic aneurysm was conducted. Consecutive patients (n = 349) undergoing EVAR between January 2007 and January 2012 were analyzed, with long-term follow-up until December 2018. Those requiring intervention were classified in accordance with the indications and specific nature of the intervention and treatment. The primary study end point was overall survival classified for patients with and without intervention. Kaplan-Meier analysis was used to estimate overall survival for those who did and who did not undergo secondary interventions. Univariable and multivariable Cox regression were performed to identify independent variables associated with mortality.

RESULTS

Some 56 patients (16%) underwent 72 secondary interventions after EVAR during a median (interquartile range) follow-up period of 53.2 months (60.1). Some 45 patients (80.4%) underwent one intervention. Indications for intervention included mainly endograft kinking/outflow obstruction and type II endoleak. An endovascular technique was used in 40.3% of interventions. Median time to secondary intervention was 24.1 months. In 93 patients with abnormalities on imaging, no intervention was performed mainly because the abnormality had disappeared on follow-up imaging (43%). Kaplan-Meier curves showed no difference in survival for patients with and without secondary interventions (P = 0.153). Age (hazard ratio [HR]: 1.089, 95% confidence interval [CI]: 1.063-1.116), ASA classification (ASA III, IV HR: 1.517, 95% CI: 1.056-2.178) were significantly related to mortality.

CONCLUSIONS

Secondary intervention rates are still considerable after EVAR. Endograft kinking/outflow obstruction and endoleak type II are the most common indications for a secondary intervention. Secondary interventions did not adversely affect long-term overall survival after EVAR.