Suprarenal Endograft Fixation Avoids Adverse Outcomes Associated with Aortic Neck Angulation

The Association between Device Instructions for Use Adherence and Outcomes after Elective Endovascular Aortic Abdominal Aneurysm Repair

OBJECTIVE

Aortic neck anatomy has a significant impact on the complexity of endovascular aortic aneurysm repair (EVAR), with concern that neck characteristics outside of instructions for use (IFU) may result in worse outcomes. Therefore, this study determined the impact of neck characteristics outside of IFU on perioperative and one-year outcomes and mid-term survival after EVAR.

METHODS

We identified all patients undergoing elective infrarenal EVAR from December 2014 to May 2020 in the Vascular Quality Initiative database. Neck characteristics outside of IFU were determined based the specific device IFU neck characteristics (Neck diameter, length, and angulation). Patients without one-year follow-up were excluded for the 1-year outcomes analyses (n=6,138 (40%)). We used multivariable adjusted logistic regression and Cox proportional hazard models to identify the independent associations between neck characteristics outside of IFU and our outcomes.

RESULTS

Of the 15,448 patients identified, 22.1% had neck characteristics outside of IFU, including 6.6% with a infrarenal angle, 6.8% with a neck length, 10.4% with a neck diameter, and 1.1% with a suprarenal angulation outside of IFU. Of these, 2.4% had more than one neck characteristic outside of IFU. Patients with neck characteristics outside of IFU were more often female (27.9% vs. 15.0%, P<.001) and were older (median age 75 vs. 73, P<.001). EVAR patients with neck characteristics outside of IFU had higher rates of type Ia endoleaks at completion (4.8% vs. 2.5%, P<.001), perioperative mortality (1.2% vs. 0.6%, P<.001), one-year sac expansion (7.1% vs. 5.3%, P=.017), and one-year reinterventions (4.4% vs. 3.2%, P=.03). In multivariable adjusted analyses, neck characteristics outside of IFU were independently associated with type Ia completion endoleaks (OR 1.6, [1.3-2.0], P<.001), perioperative mortality (OR 1.8; [1.2-2.7]; P=.005), one-year sac expansion (OR 1.4; [1.0-1.8]; P=.025) and one-year reinterventions (OR 1.4; [1.0-1.9]; P=.039). Unadjusted mid-term survival was lower for patients with neck characteristics outside of IFU than for patients without (5-year survival 84.0% vs. 86.7%, log-rank<.001). However, after adjustment, survival was similar for patients with neck characteristics outside of IFU to those within (HR: 1.1; [1.0-1.3]; P=.22).

CONCLUSION

Neck characteristics outside of IFU are independently associated with completion type Ia endoleaks, perioperative mortality, one-year sac expansion and one-year reinterventions among patients undergoing elective EVAR. These results indicate that continued effort is needed to improve the proximal seal in patients with neck characteristics outside of IFU undergoing EVAR. Also, in patients with severe hostile neck characteristics, alternative approaches such as open repair, use of a fenestrated or branched device, or endoanchors should be considered.

Effect of vertebral compression fractures on aortic neck angulation after endovascular aneurysm repair

OBJECTIVE

Aortic neck angulation (ANA) prior to endovascular aneurysm repair (EVAR) and its changes after EVAR are considered important predictors of postoperative complications. We sought to assess the effects of vertebral body height loss on ANA in patients post-EVAR.

METHODS

All patients who had undergone EVAR for infrarenal aortic aneurysms in our institution between August 2010 and December 2018 were assessed. Anterior and posterior vertebral body heights were measured in all patients on preoperative, early postoperative, and follow-up computed tomography scans (T12-L5 vertebral bodies). Patients who had significant height loss in their follow-up period were designated as the Study group. These were matched to a Control group of the same size using propensity-score matching based on age, gender, and duration between follow-up scans. Aortic neck morphology indices including ANA and its changes were measured, and information related to postoperative endoleaks and aneurysm sac size were extracted in the Study and Control groups.

RESULTS

During the follow-up period, 10 of 185 patients had a radiologically significant vertebral body compression fracture. There was no significant difference between the Study (n = 10) and Control groups in age (77.6 ± 6.9 vs 77.2 ± 7.5 years; P = .64), gender (seven males and three females in each group; P = 1.0), duration between postoperative scans (1830 ± 665 vs 1800 ± 670 days; P = .25), preoperative ANA (36.0° ± 15.6° vs 42.4° ± 18.6°; P = .41), and early postoperative ANA (21.9° ± 11.7° vs 20.9° ± 16.3°; P = .72). Changes in ANA in the postoperative period (7.2° ± 11.1° vs -4.7° ± 6.7°; P = .009; power = .838) were significantly higher in the Study group.

CONCLUSION

Post-EVAR vertebral body compression fractures exacerbate ANA. Awareness of this can guide both preoperative assessment and postoperative management and follow-up.

Prognostic Role of Severe Infrarenal Aortic Neck Angulation in Endovascular Aneurysm Repair

OBJECTIVE

To investigate whether patients with severe infrarenal aortic neck angulation have worse outcomes than those without severe angulation after endovascular aneurysm repair (EVAR).

DATA SOURCES

The HDAS (Healthcare Database Advanced Search) interface developed by NICE (National Institute for Health and Care Excellence) was used to search electronic bibliographic databases.

REVIEW METHODS

Studies comparing outcomes of standard EVAR in patients with and without severe neck angulation were considered. Pooled outcome estimates were calculated using the odds ratio (OR) or hazard ratio (HR) and 95% confidence interval (CI), using the Mantel-Haenszel or inverse variance method, as appropriate. Random effects models of meta-analysis were applied. The GRADE (Grading of Recommendation, Assessment, Development, and Evaluation) methodology was used to assess the certainty of evidence.

RESULTS

Ten studies reporting a total of 7 371 patients (1 576 with severe neck angulation and 5 795 without) were included. The studies reported medium term follow up. No statistically significant difference was found for the primary outcomes (overall mortality: HR 1.27, 95% CI 0.88 - 1.85, low certainty; aneurysm related mortality: HR 1.07, 95% CI 0.80 - 1.44, moderate certainty; aneurysm rupture: HR 1.41, 95% CI 0.66 - 2.99, low certainty). The hazard of type Ia endoleak (HR 1.86, 95% CI 1.32 - 2.61) and re-intervention was higher in patient with severe angulation (HR 1.24, 95% CI 1.01 - 1.54), but there was no significant difference in the odds of adjunctive procedures (OR 1.23, 95% CI 0.48 - 3.11), or the hazard of sac expansion (HR 0.83, 95% CI 0.44 - 1.55) or stent migration (HR 1.22, 95% CI 0.78 - 1.92). Meta-analysis of studies that conducted multiple Cox regression analysis showed no significant difference for any of the primary outcomes.

CONCLUSION

Severe neck angulation may not be a poor prognostic indicator for overall/aneurysm related mortality and rupture in the medium term after EVAR but may increase the risk of late type 1 endoleaks and re-intervention; therefore, patients require close surveillance.

Abdominal aortic aneurysms: pre- and post-procedural imaging

Abdominal aortic aneurysm (AAA) is a relatively common, potentially life-threatening disorder. Rupture of AAA is potentially catastrophic with high mortality. Intervention for AAA is indicated when the aneurysm reaches 5.0-5.5 cm or more, when symptomatic, or when increasing in size > 10 mm/year. AAA can be accurately assessed by cross-sectional imaging including computed tomography angiography and magnetic resonance angiography. Current options for intervention in AAA patients include open surgery and endovascular aneurysm repair (EVAR), with EVAR becoming more prevalent over time. Cross-sectional imaging plays a crucial role in AAA surveillance, pre-procedural assessment, and post-EVAR management. This paper will discuss the current role of imaging in the assessment of AAA patients prior to intervention, in evaluation of procedural complications, and in long-term follow-up of EVAR patients.

Challenging Anatomy Predicts Mortality and Complications After Endovascular Treatment of Ruptured Abdominal Aortic Aneurysm

Purpose: To analyze the effects of aortic anatomy and endovascular aneurysm repair (EVAR) inside and outside the instructions for use (IFU) on outcomes in patients treated for ruptured abdominal aortic aneurysms (rAAA). Methods: All 112 patients (mean age 73 years; 102 men) treated with standard EVAR for rAAA between 2000 and 2012 in 3 European centers were included in the retrospective analysis. Patients were grouped based on aortic anatomy and whether EVAR was performed inside or outside the IFU. Data on complications, secondary interventions, and mortality were extracted from the patient records. Cox regression analysis was performed to assess predictors of mortality and complications; results are presented as the hazard ratio (HR) with 95% confidence interval (CI). Survival was analyzed using the Kaplan-Meier method. Results: Of the 112 patients examined, 61 (54%) were treated inside the IFU, 43 (38%) outside the IFU, and 8 patients lacked adequate preoperative computed tomography scans for determination. Median follow-up of those surviving 30 days was 2.5 years. Mortality at 30 days was 15% (95% CI 6% to 24%) inside the IFU vs 30% (95% CI 16% to 45%) outside (p=0.087). Three-year mortality estimates were 33.8% (95% CI 20.0% to 47.5%) inside the IFU vs 56% (95% CI 39.7% to 72.2%) outside (p=0.016). At 5 years, mortality was 48% (95% CI 30% to 66%) inside the IFU vs 74% (95% CI 54% to 93%) outside (p=0.015). Graft-related complications occurred in 6% (95% CI 0% to 13%) inside the IFU and 30% (95% CI 14% to 42%) outside (p=0.015). The rate of graft-related secondary interventions was 14% (95% CI 4% to 22%) inside the IFU vs 35% (95% CI 14% to 42%) outside (p=0.072). In the multivariate analysis, neck length <15 mm (HR 8.1, 95% CI 3.0 to 21.9, p<0.001) and angulation >60° (HR 3.1, 95% CI 1.0 to 9.3, p=0.045) were independent predictors of late graft-related complications. Aneurysm neck diameter >29 mm (HR 2.5, 95% CI 1.1 to 5.9, p=0.035) was an independent predictor of overall mortality. Conclusion: Long-term mortality and complications after rEVAR are associated with aneurysm anatomy. The role of adjunct endovascular techniques and the outcome of open repair in cases with challenging anatomy warrant further study.

Endovascular repair of abdominal aortic aneurysms: vascular anatomy, device selection, procedure, and procedure-specific complications

Abdominal aortic aneurysm (AAA) is abnormal dilatation of the aorta, carrying a substantial risk of rupture and thereby marked risk of death. Open repair of AAA involves lengthy surgery time, anesthesia, and substantial recovery time. Endovascular aneurysm repair (EVAR) provides a safer option for patients with advanced age and pulmonary, cardiac, and renal dysfunction. Successful endovascular repair of AAA depends on correct selection of patients (on the basis of their vascular anatomy), choice of the correct endoprosthesis, and familiarity with the technique and procedure-specific complications. The type of aneurysm is defined by its location with respect to the renal arteries, whether it is a true or false aneurysm, and whether the common iliac arteries are involved. Vascular anatomy can be divided more technically into aortic neck, aortic aneurysm, pelvic perfusion, and iliac morphology, with grades of difficulty with respect to EVAR, aortic neck morphology being the most common factor to affect EVAR appropriateness. When choosing among the devices available on the market, one must consider the patient's vascular anatomy and choose between devices that provide suprarenal fixation versus those that provide infrarenal fixation. A successful technique can be divided into preprocedural imaging, ancillary procedures before AAA stent-graft placement, the procedure itself, postprocedural medical therapy, and postprocedural imaging surveillance. Imaging surveillance is important in assessing complications such as limb thrombosis, endoleaks, graft migration, enlargement of the aneurysm sac, and rupture. Last, one must consider the issue of radiation safety with regard to EVAR.

Active Proximal Sealing in the Endovascular Repair of Abdominal Aortic Aneurysms

Purpose: To investigate the performance of a new device that uses the STRATA polytetrafluoroethylene graft material and a mechanism that provides active proximal sealing in order to prevent type Ia endoleak during endovascular aneurysm repair (EVAR). Methods: Between April 2013 and July 2014, 21 consecutive patients (all men; median age 71 years, range 60–84 years) with abdominal aortic aneurysm (median diameter 5.9 cm, range 4.9–7.8 cm) and suitable anatomy were offered elective EVAR using the AFX endograft. These patients had an irregular, conical, tapered, or bulging proximal neck, for which this specific device was considered appropriate. Aneurysm exclusion and incidence of type Ia endoleak were the primary outcomes; secondary outcomes included mortality, morbidity, migration, and other graft-related complications. Results: Primary technical success was 90%; 2 intraoperative type Ia endoleaks due to low endograft deployment were treated with additional proximal cuffs. During a median follow-up of 10 months (range 2–15 months), no type I endoleak was observed. One type II endoleak was encountered, with no associated sac enlargement. There was no stent-graft migration or any other device-related complication. One patient had a nonfatal myocardial infarction and another developed renal failure requiring transient dialysis. No deaths occurred. Conclusion: In this early experience, this newly available device appears to be safe and efficient in providing seal along irregularly shaped necks over the short term.

[Aortic stent migration: a rare complication after endovascular repair]

Migration of an aortic stent is one of the most serious complications that can occur during follow-up after endovascular repair of an abdominal aortic aneurysm. We report the case of a 75-year-old man who underwent endovascular treatment for an infra-renal aortic aneurysm using an aorto-mono-iliac stent associated to a femoro-femoral bypass. The angiography performed at the end of procedure showed complete exclusion of the aneurysm. The postoperative course was uneventful. CT scans at 1, 6 and 12 months were normal. The CT scan at the 18th month showed a proximal migration of the stent, which was complicated by a type 1 endoleak and a stent disjunction with a type 3 endoleak. Revision surgery was indicated but the patient died from aneurismal rupture pending treatment. The migration of an aortic stent is a rare but serious complication of endovascular aneurysmal repair. Prevention requires a precise anatomical selection and adequate deployment of the stent graft.

Endovascular treatment of infrarenal abdominal aortic aneurysm with short and angulated neck in high-risk patient

Endovascular treatment of abdominal aortic aneurysms (AAA) is an established alternative to open repair. However lifelong surveillance is still required to monitor endograft function and signal the need for secondary interventions (Hobo and Buth 2006). Aortic morphology, especially related to the proximal neck, often complicates the procedure or increases the risk for late device-related complications (Hobo et al. 2007 and Chisci et al. 2009). The definition of a short and angulated neck is based on length (<15 mm), and angulation (>60°) (Hobo et al. 2007 and Chisci et al. 2009). A challenging neck also offers difficulties during open repairs (OR), necessitating extensive dissection with juxta- or suprarenal aortic cross-clamping. Patients with extensive aneurysmal disease typically have more comorbidities and may not tolerate extensive surgical trauma (Sarac et al. 2002). It is, therefore, unclear whether aneurysms with a challenging proximal neck should be offered EVAR or OR (Cox et al. 2006, Choke et al. 2006, Robbins et al. 2005, Sternbergh III et al. 2002, Dillavou et al. 2003, and Greenberg et al. 2003). In our case the insertion of a thoracic endograft followed by the placement of a bifurcated aortic endograft for the treatment of a very short and severely angulated neck proved to be feasible offering acceptable duration of aneurysm exclusion. This adds up to our armamentarium in the treatment of high-risk patients, and it should be considered in emergency cases when the fenestrated and branched endografts are not available.

Coupling bifurcated stent-grafts to overcome anatomic limitations of endovascular repair of abdominal aortic aneurysms

PURPOSE

To evaluate the effectiveness of the coupling stent-graft technique and outcomes on contrast-enhanced computed tomography (CT).

MATERIALS AND METHODS

All patients who underwent endovascular aneurysm repair (EVAR) for abdominal aortic aneurysms (AAAs) between 2007 and 2010 at a single institution were retrospectively analyzed. Of the 161 cases, 19 patients who had coupling stent-grafting because of AAA proximal neck angulation greater than 60°, conical neck, or iliac tortuosity were included. Patient age ranged from 62 to 87 years (mean, 73.3 y). Mean follow-up was 18.7 months (range, 1-36 mo). The coupling stent-graft technique was defined by the use of suprarenal fixation device main bodies (Zenith or Talent) with one or more EXCLUDER limbs to adapt tortuous and angulated iliac arteries. Pretreatment contrast-enhanced CT was analyzed based on three-dimensional and multiplanar reformatted images. Follow-up contrast-enhanced CT was also analyzed.

RESULTS

Mean aneurysm diameter was 68.9 mm ± 14.0, neck length was 32.7 mm ± 15.1, and neck angulation was 68.9° ± 11.5. Conical neck shapes were present in four patients (21.1%) and ruptured AAAs were present in two (10.5%). Among 38 iliac arteries, the mean iliac artery tortuosity index was 1.52 ± 0.27 and iliac angle was 106.8° ± 18.1. Three patients (15.8%) underwent repeat intervention: placement of a balloon-expandable stent in the proximal neck for type I endoleak (n = 1), endovascular embolization for proximal type I endoleak (n = 1), and percutaneous approach following endovascular embolization for type II endoleak (n = 1). No type III endoleak, limb occlusion, limb kinking, or stent-graft migration developed.

CONCLUSIONS

The coupling stent-graft technique is technically feasible, with acceptable midterm outcomes in EVAR of AAA in patients with unfavorable neck and iliac anatomies.

Early results of the Endurant endograft system in patients with friendly and hostile infrarenal abdominal aortic aneurysm anatomy

OBJECTIVE

To evaluate and compare the outcome after endovascular abdominal aortic aneurysm repair (EVAR) with the newly released Endurant endograft system in patients with different aortoiliac anatomic characteristics.

METHODS

We conducted a prospective observational study assigning patients with infrarenal abdominal aortic aneurysm (AAA) treated with the Endurant endoprosthesis from February 2009 to March 2010. Two groups were studied, according to the presence of a friendly (group I [GI] = 43) or hostile (group II [GII] = 34) infrarenal aortoiliac anatomy. Hostile profile was defined as any (or combination) of the following measurements: 5 mm ≤ proximal neck length (Lpr) ≤ 12 mm, 60° < proximal neck angle (A°pr) ≤ 90° and 60° < any iliac axis angle (A°iliac) ≤ 90°. Primary end points included technical and clinical success, freedom from early or late secondary interventions, any type of endoleak, and aneurysm-related death. All outcome measures were calculated using the Kaplan-Meier method and the log rank test was applied for comparisons between the groups.

RESULTS

The mean comorbid severity scoring was higher in GII (P = .018). The mean follow-up period in GI and GII was 12.9 ± 3.9 months (± SD, range: 6.4-19.8) and 12.4 ± 4 months (range: 4.2-19.6), respectively. Two unplanned conversions to aortouniiliac configurations were required in GI. The technical success rate in GI and GII was 95.4% and 100%, respectively. The requirement for intentional occlusion of the internal iliac artery, the requirement for cross-limb technique, the necessity of troubleshooting techniques, the procedure and radiation times, the frequency of postimplantation syndrome, and mean hospital stay were significantly higher in GII (P = .028, P = .013, P = .005, P = .037, P < .001, P = .032, P = .021, respectively). Two patients of GI died in the early postoperative period (one aneurysm but not device-related death), whereas no deaths in GII were recorded, yielding an overall 30-day mortality rate of 2.3%. No type I/III endoleaks were recorded up to the end of the study. Freedom from any type of endoleak, early or late secondary interventions, and aneurysm-related death at 12 months were found in 93.2%, 87.1%, and 93.3% of GI patients; respective values for GII were 86% (P = .21), 93.4% (P = .066), and 93.4%. The clinical success rate was 82.1% and 100% at 12 months for GI and GII, respectively.

CONCLUSIONS

Early (12 months) results suggest similar clinical performance of the Endurant stent graft system in endovascular treatment of AAAs with friendly and hostile anatomies, however, demonstrating more intra- and perioperative adversities for the last group. Larger prospective studies or even randomized trials comparing different new generation graft models are required to evaluate the comparable long-term results and possible expansion of EVAR indications for this specific endograft in adverse anatomies.

Alternative Technique for Endovascular Treatment of an Abdominal Aortic Aneurysm With a Severely Angulated Neck

An 86-year-old female was incidentally discovered with an asymptomatic 5.3 cm infrarenal aortic aneurysm. Preoperative imaging demonstrated the aortic neck to have severe suprarenal and infrarenal angulation. The patient was deemed unfit for open aortic repair due to multiple medical comorbidities. Endovascular treatment was performed with a modified Zenith bifurcated graft using a Zenith TX2 endograft as a proximal aortic cuff. There were no perioperative complications, and postoperative imaging demonstrated aneurysm exclusion with no migration or major endoleaks. The patient died of unrelated causes at 21 months. The use of a thoracic endograft as a proximal cuff is an alternative technique in the endovascular treatment of abdominal aortic aneurysms with a severely angulated neck.

Clinical outcomes for hostile versus favorable aortic neck anatomy in endovascular aortic aneurysm repair using modular devices

BACKGROUND

Endovascular aneurysm repair (EVAR) is not generally recommended for patients with hostile neck anatomy. This study analyzed the clinical implications of various clinical features of proximal aortic neck anatomy.

METHODS

Prospectively collected data from 258 EVAR patients using modular devices were analyzed. Patients were classified as having favorable neck anatomy (FNA) or hostile neck anatomy (HNA). HNA was defined as any or all of length of <10 mm, angle of >60°, diameter of >28 mm, ≥50% circumferential thrombus, ≥50% calcified neck, and reverse taper. Univariate, multivariate, and Kaplan-Meier analyses were used to compare early and late clinical outcomes.

RESULTS

FNA was present in 37% and HNA was present in 63%. Clinical and demographic characteristics were comparable. Technical success was 99%. Mean follow-up was 22 months (range, 1-78 months). Perioperative complication rates were 3% for FNA vs 16% for HNA (P = .0027). Perioperative deaths were 0% for FNA and 3% for HNA (P = .2997). Proximal type I early endoleaks (intraoperative) occurred in 9% of FNA vs 22% for HNA (P = .0202). Intraoperative proximal aortic cuffs were used to seal endoleaks in 9% of FNA vs 22% of HNA (P = .0093). At late follow-up, abdominal aortic aneurysm expansion was noted in 6% of FNA vs 7% of HNA (P = .8509). Rates of freedom from late type I endoleaks at 1, 2, 3, and 4 years were 97%, 97%, 97%, and 90% for FNA vs 89%, 89%, 89%, and 89% for HNA (P = .1224); rates for late interventions were 95%, 90%, 90%, and 90% for FNA vs 95%, 93%, 91%, and 85% for HNA (P = .6902). Graft patency at 1, 2, and 3 years was 99%, 99%, and 99% for FNA vs 97%, 92%, and 90% for HNA (P = .0925). The survival rates were 93%, 84%, 76%, and 76% for FNA vs 88%, 82%, 74%, and 66% for HNA (P = .2631). Reverse taper was a significant predictor for early type I endoleak (odds ratio [OR], 5.25, P < .0001), reverse taper (OR, 5.95; P < .0001) and neck length (OR, 4.15; P = .0146) were for aortic cuff use; circumferential thrombus (OR, 2.44; P = .0448), and neck angle (OR, 3.38; P = .009) were for perioperative complications.

CONCLUSIONS

Patients with HNA can be treated with EVAR, but with higher rates of early (intraoperative) type I endoleak and intervention. The midterm outcomes are similar to FNA.

Thoracic Endograft for Abdominal Aortic Aneurysms, an Unusual Application for Severe Neck Angulation: Case Report and Literature Review

Our goal was to achieve complete proximal sealing in severe aortic neck angulation (SNA) during endovascular aneurysm repair (EVAR) of a patient with an abdominal aortic aneurysm (AAA) unfit for surgery. An 82-year-old patient with an infrarenal AAA of 9.8 cm with an SNA of 90° was admitted for acute coronary syndrome. Following coronary treatment, the patient was considered unfit for surgery and therefore was evaluated for EVAR. Aneurysm sac exclusion was obtained with the deployment of a Powerlink bifurcated graft (Endologix Inc, Irvine, CA) inside a Relay thoracic endograft (Bolton Medical, Florida) placed just below the most distal renal artery. At 6 months, computed tomographic angiography confirmed correct graft placement, complete aneurysm exclusion, and a reduction in the aneurysmal sac. In AAA patients with an SNA at high risk of EVAR failure, the adaptability of a thoracic endograft could be considered for proximal sealing.

Early and Late Clinical Outcomes of Endovascular Aneurysm Repair in Patients with an Angulated Neck

This study analyzed the clinical outcome in endovascular aneurysm repair (EVAR) patients with an angulated aortic neck. Two hundred thirty-eight EVAR patients underwent postoperative duplex ultrasonography and/or computed tomographic angiography, which was repeated every 6 to 12 months. Aortic neck angle was classified into < 45° (A1, n= 129), ≥ 45 to < 60° (A2, n = 43), and ≥ 60° (A3, n = 42). The perioperative complication rates for groups A1, A2, and A3 were 13%, 5%, and 29%, respectively ( p = .006). Proximal type I early endoleaks occurred in 9%, 33%, and 38% in groups A1, A2, and A3, respectively ( p < .0001). Intraoperative proximal aortic cuffs were needed in 7%, 28%, and 33% in groups A1, A2, and A3, respectively ( p < .0001). However, the rate of late reintervention was comparable in all groups. Postoperatively, the size of abdominal aortic aneurysm decreased or remained unchanged in 97%, 95%, and 84% in A1, A2, and A3, respectively ( p = .0147). The rates of freedom from late type I endoleak at 1, 2, and 3 years were 90%, 85%, and 85% for A1; 74%, 74%, and 68% for A2; and 64%, 64%, and 53% for A3 ( p = .0013). EVAR can be used for patients with an angulated aortic neck but was associated with a higher rate of early and late type I endoleaks and early interventions.

Early in Vivo Analysis of an Endovascular Stapler During Endovascular Aneurysm Repair

The objective of this article is to describe the use and technique of a novel endostapling device used in an in vivo animal model. Six ovine underwent implantation of a Dacron endograft into the thoracic aorta followed by placement of endoclips proximally and distally. The animals were survived 35 days to evaluate the performance and safety of the endoclip in an animal model prior to clinical trials. The mean time for securing both the proximal and the distal anastomosis was 22 minutes (range 17–31 minutes). All staples were deployed, without the need for repositioning, on the first attempt. There were no complications related to the implant procedure or indwelling clips. Additionally, no endograft migration occurred. At the time of expiant, staples were evaluated for depth of penetration and accuracy of placement. The staples had fully penetrated the endograft and vessel wall through the adventitia in 89% (64 of 72) of clips deployed. The staples were placed accurately, within 10 mm of the endograft proximal and distal attachments in 94% (68 of 72) of the clips deployed. Furthermore, endothelialization of the staples was present without surrounding thrombus. Implant sites were scored as normal without surrounding tissue damage by an independent pathologist. The endoclip performed well in creating proximal and distal fixation of the endograft. There were no adverse outcomes related to the endostaple. Future clinical trials should be undertaken to assess its clinical utility during endovascular aneurysm repair.

Suprarenal endograft fixation and medium-term renal function: systematic review and meta-analysis

BACKGROUND

Suprarenal fixation is widely used in endovascular aneurysm repair. Numerous small, underpowered studies have concluded that it does not increase the risk of renal impairment compared with infrarenal fixation. A recent meta-analysis demonstrated that renal infarction is more common with suprarenal fixation, but the effect on renal function remains unclear.

METHODS

Electronic abstract databases, article reference lists, and conference proceedings were searched for series reporting renal function data after suprarenal fixation. There was considerable study heterogeneity with respect to key factors such as pre-existing renal dysfunction and length of follow-up. Authors were contacted to obtain individual patient data for a pooled reanalysis using standardized criteria.

RESULTS

Of 46 potentially relevant citations, only 11 were eligible for inclusion in the meta-analysis. Complete data sets were available for four studies (1065 patients), with a median follow-up of 33 months. Kaplan-Meier curves were constructed for postoperative renal impairment in the suprarenal fixation and infrarenal fixation groups and compared by the log-rank test. Median time free of renal impairment was 38.5 months in the infrarenal fixation group compared with 32.4 months in the suprarenal fixation group (P = .0038). However, to account for significant methodologic differences, further analysis was required using a Weibull regression model fitted in open Bayesian inference using Gibbs sampling (BUGS). The pooled hazard ratio for deterioration of renal function after suprarenal fixation was 0.6 (95% confidence interval, 0.3-10).

CONCLUSION

Currently available data are insufficient to determine the precise effect of suprarenal fixation on medium-term renal function. Conventional Kaplan-Meier analysis of the pooled data set suggested that suprarenal fixation increased the risk of renal dysfunction; however, the effect disappeared when sophisticated statistical modelling was performed to account for study heterogeneity. A randomised controlled trial of suprarenal fixation may resolve this issue.

Influence of Severe Infrarenal Aortic Neck Angulation on Complications at the Proximal Neck Following Endovascular AAA Repair: A EUROSTAR Study

PURPOSE

To examine the influence of severe infrarenal neck angulation (SNA) on complications after endovascular repair of abdominal aortic aneurysm (AAA).

METHODS

From October 1996 to January 2006, 5183 patients who underwent endovascular aneurysm repair using a Talent, Zenith, or Excluder stent-graft were enrolled into the EUROSTAR registry. Incidence of proximal type I endoleak, stent-graft migration, proximal neck dilatation, aneurysm rupture, secondary interventions, and all-cause and aneurysm-related mortality were compared between patients with and without severe infrarenal neck angulation (>60 degrees angle between the infrarenal aortic neck and the longitudinal axis of the aneurysm).

RESULTS

In the short term (before discharge), proximal type I endoleak (OR 2.32, 95% CI 1.60 to 3.37, p<0.0001) and stent-graft migration (OR 2.17, 95% CI 1.20 to 3.91, p=0.0105) were observed more frequently in patients with SNA. Over the long term, higher incidences of proximal neck dilatation > or =4 mm (HR 1.26, 95% CI 1.11 to 1.43, p=0.0004), proximal type I endoleak (HR 1.80, 95% CI 1.25 to 2.58, p=0.0016), and need for secondary interventions (HR 1.29, 95% CI 1.00 to 1.67, p=0.0488) were seen in patients with SNA. All-cause mortality, aneurysm-related mortality, and rupture of the aneurysm were similar in patients with and without severe neck angulation. In the subgroup of patients with an Excluder endograft, proximal endoleak at the completion angiogram (OR 4.49, 95% CI 1.31 to 15.32, p=0.0166) and long-term proximal neck dilatation (HR 1.67, 95% CI 1.20 to 2.33, p=0.0026) were more frequently observed in patients with SNA. In the Zenith subgroup, proximal endoleak at the completion angiogram (OR 2.62, 95% CI 1.49 to 4.63, p=0.0009) and proximal stent-graft migration before discharge (OR 2.34, 95% CI 1.06 to 5.19, p=0.0353) were more common in patients with SNA. In the Talent subgroup, long-term proximal endoleak (HR 2.09, 95% CI 1.27 to 3.44, p=0.0036), proximal neck dilatation (HR 1.29, 95% CI 1.05 to 1.60, p=0.0168), and secondary interventions (HR 1.54, 95% CI 1.05 to 2.24, p=0.0259) were more frequently observed in patients with SNA.

CONCLUSION

Severe infrarenal aortic neck angulation was clearly associated with proximal type I endoleak, while the relationship with stent-graft migration was not clear. Excluder, Zenith, and Talent stent-grafts perform well in patients with severe neck angulation, with only a few differences among devices.

Outcomes of Endovascular Abdominal Aortic Aneurysm Repair in Patients with Hostile Neck Anatomy

PURPOSE

The principal anatomic contraindication to endovascular aneurysm repair (EVR) is an unfavorable proximal aortic neck. With increasing experience, a greater proportion of patients with unfavorable neck anatomy are being offered EVR. This study aimed to evaluate outcomes in patients with challenging proximal aortic neck anatomy.

METHODS

Prospectively collected data from 147 consecutive patients who underwent EVR between December 1997 and April 2005 were supplemented with a retrospective review of medical records and radiological images. Unfavorable anatomic features were defined as neck diameter >28 mm, angulation >60 degrees, circumferential thrombus >50%, and length <10 mm. Eighty-seven patients with 0 adverse features (good necks) were compared with 60 patients with one or more adverse features (hostile necks).

RESULTS

Comparing the good neck with the hostile neck group, there were no significant differences in the incidence of primary technical success (p = 0.15), intraoperative adjunctive procedures (p = 0.22), early proximal type I endoleak (<30 days) (p = 1.0), late proximal type I endoleak (>30 days) (p = 0.57), distal type I endoleak (p = 0.40), type III endoleak (p = 0.51), secondary interventions (p = 1.0), aneurysm sac expansion (p = 0.44), or 30 day mortality (p = 0.70). The good neck group had a significantly increased incidence of type II endoleak (p = 0.023). By multivariate analysis, the incidence of intraoperative adjunctive procedures was significantly increased in the presence of severe angulation (p = 0.041, OR 3.08, 95% CI 1.05-9.04).

CONCLUSION

Patients with severely hostile proximal aortic neck anatomy may be treated with EVR, although severely angulated necks require additional intraoperative procedures. Early outcomes are encouraging and suggest that indications for EVR may be expanded to include patients with hostile neck anatomy.

Three-dimensional visualization of suprarenal aortic stent-grafts: evaluation of migration in midterm follow-up

PURPOSE

To investigate the midterm results of transrenal fixation of abdominal aortic stent-grafts with regard to device migration and encroachment of stent wires on the renal and visceral branches.

METHODS

Imaging data from 18 patients (15 men; mean age 75 years, range 63-84) undergoing transrenal stent-graft fixation for abdominal aortic aneurysm (AAA) were included in the study. Computed tomographic angiographic data acquired within 1 week of stent-graft implantation were compared to the latest follow-up images. Postprocessing methods generated 3-dimensional (3D) maximum intensity projections (MIP) and virtual intravascular endoscopy (VIE) for evaluation of the relationship between suprarenal stents and aortic branches. Aortic neck angulation was measured in each patient for correlation with the incidence of stent migration.

RESULTS

The mean follow-up period was 40 months. 3D image visualizations showed that the stent-graft moved caudally in all patients (range 2.6-14.2 mm), with migration (>10 mm) observed in 4 (22%) patients. Corresponding VIE images documented changes in stent wire encroachment on the aortic branch ostia in 11 patients, including the number and position of crossing stent wires. There was no close relationship between aortic neck angulation and stent migration.

CONCLUSION

The current study demonstrated that migration occurs at midterm follow-up in transrenally deployed stent-grafts. 3D images were valuable for the assessment of stent migration, as well as its relationship with aortic branch ostia. Long-term follow-up of transrenal fixation deserves to be investigated, especially after observing stent migration relative to aortic ostial encroachment.

Endovascular repair of abdominal aortic aneurysms: CTA evaluation of contraindications

Endovascular aortic aneurysm repair (EVAR) is considered an acceptable alternative to open surgery in selected patients. Its feasibility depends mainly on anatomic factors that represent the important predictors of success and the most important exclusion criteria. Poor anatomic patient selection is generally associated with a higher risk for procedural complications and compromised long-term outcomes. Therefore pretreatment imaging is crucial for evaluating patient suitability for EVAR. Multidetector computed tomographic angiography represents the current standard of reference in the evaluation of the abdominal aorta and iliac axis anatomy because it provides all the details needed for selection of patients who are suitable for endograft and the choice of the appropriate device. This report identifies and reviews computed tomographic angiographic anatomic contraindications for EVAR.

Endovascular aneurysm repair with suprarenal vs infrarenal fixation: A study of renal effects

OBJECTIVES

Although suprarenal fixation may be of benefit during endovascular aneurysm repair (EVAR), its safety with regards to renal effects remains uncertain. To date, there has been no controlled study of the topic, with most reports relying upon single-center experiences that use heterogeneous patient populations and devices from different manufacturers. The purpose of this analysis was to evaluate the effect of suprarenal fixation on renal function by comparing homogeneous patient populations receiving EVAR grafts from a single manufacturer that are identical in design and delivery method, except for utilizing either suprarenal (SR) or infrarenal (IR) fixation.

METHODS

During two pivotal US Food and Drug Administration trials, 283 patients underwent EVAR with the Powerlink bifurcated graft. The trials' inclusion and exclusion criteria and grafts were identical except for fixation scheme. Clinical, laboratory, and computed tomographic (CT) data were retrospectively reviewed. A comparison of preoperative, perioperative (1 to 7 days), and postoperative (>7 days) alterations in serum creatinine (SCr), creatinine clearance (CrCl), and blood pressure was performed. Renal adverse events were determined by CT scan and clinical chart review and included renal infarction, renal artery stenosis (either progressive or requiring renal stent placement), and renal artery occlusion.

RESULTS

Both SR and IR groups demonstrated a significant increase in SCr and a decrease in CrCl over time. No significant difference in SCr or CrCl existed between groups during any time period. There were no differences in postoperative renal impairment (IR, 10.2%; SR, 7.6%, P = .634), the need for hemodialysis (IR, 0.7%; SR, 0%, P = 1.00), or systolic and diastolic blood pressure during subsequent follow-up between treatment groups. There was no significant difference in the number of renal adverse events detected by CT between the IR (10, 6.8%) and SR (3, 3.8%) groups (P = .550).

CONCLUSION

Suprarenal fixation does not lead to a significant increase in acute renal events, renal impairment, or alteration in blood pressure compared with infrarenal fixation. Patients undergoing aneurysm repair with devices that use either suprarenal or infrarenal fixation develop progressive renal dysfunction over time. Further studies are needed to determine the long-term effects of suprarenal fixation on renal function and progression of renal artery stenosis.