Aortoiliac morphologic correlations in aneurysms undergoing endovascular repair

Novel Risk Score Calculator for Perioperative Mortality after EVAR with Incorporation of Anatomical Factors

BACKGROUND

Hostile proximal aortic neck anatomy has been associated with an increased risk of perioperative mortality after endovascular aneurysm repair (EVAR). However, all available mortality risk prediction models after EVAR lack neck anatomic associations. The aim of this study is to develop a preoperative prediction model for perioperative mortality after EVAR incorporating important anatomic factors.

METHODS

Data were obtained from the Vascular Quality Initiative database on all patients who underwent elective EVAR between January 2015 and December 2018. A stepwise multivariable logistic regression analysis was implemented to identify independent predictors and develop a risk calculator for perioperative mortality after EVAR. Internal validation was done using bootstrap of 1,000 reps.

RESULTS

A total of 25,133 patients were included, of whom 1.1% (N = 271) died within 30 days or before discharge. Significant preoperative predictors of perioperative mortality were age (odds ratio [OR], 1.053; 95% confidence interval [CI], 1.050-1.056; P < 0.001), female sex (OR, 1.46; 95% CI, 1.38-1.54; P < 0.001), chronic kidney disease (OR, 1.65; 95% CI, 1.57-1.73; P < 0.001), chronic obstructive pulmonary disease (OR, 1.86; 95% CI, 1.77-1.94; P < 0.001), congestive heart failure (OR, 2.02; 95% CI, 1.91-2.13, P < 0.001), aneurysm diameter ≥ 6.5 cm (OR, 2.35; 95% CI, 2.24-2.47, P < 0.001), proximal neck length < 10 mm (OR, 1.96; 95% CI, 1.81-2.12; P < 0.001), proximal neck diameter ≥ 30 mm (OR, 1.41; 95% CI, 1.32-1.5; P < 0.001), infrarenal neck angulation ≥ 60° (OR, 1.27; 95% CI, 1.18-1.26; P < 0.001), and suprarenal neck angulation ≥ 60° (OR, 1.26; 95% CI, 1.16-1.37; P < 0.001). Significant protective factors included aspirin use (OR, 0.89; 95% CI, 0.85-0.93; P < 0.001) and statin intake (OR, 0.77; 95% CI, 0.73-0.81; P < 0.001). These predictors were incorporated to build an interactive risk calculator of perioperative mortality after EVAR (C-statistic = 0.749).

CONCLUSIONS

This study provides a prediction model for mortality following EVAR that incorporates aortic neck features. The risk calculator can be used to weigh risk/benefit ratio when counseling patients preoperatively. Prospective use of this risk calculator may show its benefit in long-term prediction of adverse outcomes.

Infrarenal Remains Infrarenal-EVAR Suitability of Small AAA Is Rarely Compromised despite Morphological Changes during Surveillance

The aim was to analyze small abdominal aortic aneurysm (AAA) morphology during surveillance with regard to standard endovascular aortic repair (EVAR) suitability. This retrospective single-center study included all patients (n = 52, 48 male, 70 ± 8 years) with asymptomatic AAA ≤ 5.4 cm undergoing ≥2 computed tomography angiography(CTA)/magnetic resonance imaging (MRI) studies (interval: ≥6 months) between 2010 and 2018. Aneurysm diameter, neck quality (shape, length, angulation, thrombus/calcification), aneurysm thrombus, and distal landing zone diameters were compared between first and last CTA/MRI. Resulting treatment plan changes were determined. Neck shortening occurred in 25 AAA (mean rate: 2.0 ± 4.2 mm/year). Neck thrombus, present in 31 patients initially, increased in 16. Average AAA diameters were 47.7 ± 9.3 mm and 56.3 ± 11.6 mm on first and last CTA/MRI, mean aneurysm growth rate was 4.2 mm/year. Aneurysm thrombus was present in 46 patients primarily, increasing in 32. Neck thrombus growth and neck length change, aneurysm thrombus amount and aneurysm growth and aneurysm growth and neck angulation were significantly correlated. A total of 46 (88%) patients underwent open (12/46) or endovascular (34/46) surgery. The planned procedure changed from EVAR to fenestrated EVAR in two patients and from double to triple fenestrated EVAR in one. Thus, standard EVAR suitability was predominantly maintained as the threshold diameter for surgery was reached despite morphological changes. Consecutively, a possibly different pathogenesis of infra- versus suprarenal AAA merits further investigation.

The Correlation Of Aortic Neck Length To Late Outcomes Following EVAR with the Ovation Stent Graft

BACKGROUND

Endovascular aneurysm repair (EVAR) performed outside manufacturers' instructions for use (IFU) due to short aortic neck for the treatment of abdominal aortic aneurysm (AAA) is associated with unfavorable outcomes. Newer endografts now have an indication for shorter neck aneurysms that previous endografts do not, but this cohort has yet to be evaluated individually. The aim of this study is to evaluate 5-year outcomes after EVAR in patients with short aortic necks (<10mm) using the Ovation stent graft.

METHODS

The study comprised 238 patients who underwent EVAR as part of the prospective international multicenter Ovation stent graft trials. The main inclusion criteria were AAA diameter ≥ 5cm, proximal parallel neck length ≥7mm, neck angulation ≤60° and bilateral iliac fixation length ≥10 mm. A clinical events committee adjudicated adverse events through 1 year, an independent imaging core laboratory analyzed imaging through 5 years and a data safety and monitoring board provided study oversight. Patients were divided into short neck (<10mm) and standard neck (≥10mm) groups. Endpoints included long-term survival, freedom from aneurysm-related mortality (ARM), freedom from type Ia Endoleak and freedom from reintervention.

RESULTS

Patients were predominantly male (81%) with a mean age of 73±8 years. Median follow-up time was 58 months (IQR 36-60). Out of 238 patients, 41 (17.2%) had a proximal neck length <10mm and would be considered outside the IFU with other stent grafts. Baseline characteristics were relatively similar between the two groups. The 5-year overall survival estimates were 77.8% for the standard neck group compared to 59.5% for the short neck group (P= .03) (Figure1). There were no differences in the 5-year freedom from ARM (99.2% vs. 100%, P= .7), freedom from type Ia Endoleak (96.3% vs. 96.3%, P= .8) and freedom from reintervention (77.9% vs. 79.7%, P= .7) between the standard and short neck groups, respectively. After adjusting for age and other potential confounders, short proximal neck was associated with a 2-fold increase in 5-year all-cause mortality [aHR(95%CI): 2(1.02-3.8), P= .04].

CONCLUSION

The Ovation endograft performed well in short AAA neck with no difference in 5-year type Ia Endoleak, reintervention and ARM rates. However, short proximal neck was independently associated with a two-fold increase in the risk of all-cause mortality at five years. These findings confirm the prior literature on the association of hostile neck anatomy with late mortality following EVAR.

Nellix endovascular aneurysm-sealing system: a single-center experience and review of current evidence

Aims: We report the 6-year results of our use of the Nellix^® endovascular aneurysm sealing system. Materials & methods: This is a retrospective review of patients we treated from 2013 to 2019. The outcomes described include technical success rate, mortality, all procedure-related complications, reinterventions, open surgical conversion and secondary sac rupture. Results & conclusions: A total of 68 patients were treated. Mortality was 2.9%. Secondary interventions were carried out for distal embolization (3), stent occlusion (1), pseudoaneurysm (1) and endoleak (5). Open surgical conversion was required in 6.4% of cases. Medium- and long-term complications of EVAS occurred more frequently than expected. Because the durability of endovascular aneurysm sealing is questionable, strict postoperative surveillance of Nellix is crucial to identify features of failure.

Three-Year Results of the Nellix Endovascular Aneurysm Sealing System for Treatment of Abdominal Aortic Aneurysms in Frail Patients with Poor Anatomical Features

Introduction:

Endovascular aneurysm sealing represents an alternative to advanced technology devices for compromised patients with abdominal aortic aneurysms. We report our results of 15 fragile patients with very low-quality infrarenal necks treated with endovascular aneurysm sealing.

Material and methods:

All patients treated with Nellix device in our hospital between June 2015 and October 2016 were retrospectively reviewed. The primary endpoints are the following: overall survival and freedom from reintervention rates. The secondary endpoints are the following: technical success; 30-day mortality; abdominal aortic aneurysm–related mortality; and freedom from endoleak rate, complications, and surgical conversion rate.

Results:

Nellix was used in 15 patients, median age 75.5 years, of which 67% were unfit for open surgery. Mean aneurysm diameter was 60 mm. One-third (5/15) of the patients were inside the Nellix instructions for use. Technical success rate was 93.3%. No perioperative complications existed, and 30-day mortality was 0%. Median follow-up was 35 (interquartile range: 11–37) months. Survival rates at 1 and 3 years were 80% and 59.3%. Abdominal aortic aneurysm–related mortality occurred in 3 of 15 cases. Freedom from rupture rates at 1 and 3 years were 92.9% and 66%. Freedom from endoleak rates at 1 and 3 years were 92.9% and 74.5%. Freedom from reintervention rates at 1 and 3 years were 86.7% and 70.6%, with a dramatic drop to 37.1% at 4 years of follow-up. Three open surgery conversions were needed. There were no statistically significant differences in results between patients treated inside and outside instructions for use.

Conclusion:

The endovascular aneurysm sealing has shown encouraging short-term results, but its safety and effectiveness during time is questionable, because this system still carries high rates of reintervention, conversions for type IA endoleaks, and secondary aneurysm ruptures.

Two-Year Outcomes of the Nellix EndoVascular Aneurysm Sealing System for Treatment of Abdominal Aortic Aneurysms

Purpose: To analyze the 2-year outcomes of endovascular aneurysm sealing (EVAS) according to 2 versions of the instructions for use (IFU). Methods: A retrospective study was conducted involving 355 consecutive patients treated with the first-generation EVAS device from April 2013 to December 31, 2015, at 3 high-volume centers. Out of 355 patients treated with EVAS, 264 were elective asymptomatic infrarenal EVAS procedures suitable for analysis. In this cohort, 168 (63.3%) patients were treated within the IFU 2013 criteria; of these 48 (18.2%) were in compliance with the revised IFU 2016 version. Results: Overall technical success was 98.2% (165/168) in the IFU 2013 group and 97.9% (47/48) in the IFU 2016 subgroup (p=0.428). The 2-year freedom from reintervention estimates were 89.7% (IFU 2013) and 95.7% (IFU 2016), with significantly more reinterventions in the first 45 cases (p=0.005). The stenosis/occlusion estimates were 6.5% (IFU 2013) and 4.2% (IFU 2016; p=0.705). Nine (5.4%) endoleaks (8 type Ia and 1 type Ib) were observed within the IFU 2013 cohort; 3 (2.1%) were in the IFU 2016 subgroup (p=0.583). Migration ≥10 mm or ≥5 mm requiring intervention was reported in 12 (7.1%) patients in the IFU 2013 cohort but none within the IFU 2016 subgroup. Ten (6.0%) patients demonstrated aneurysm growth in the IFU 2013 cohort, of which 2 (4.2%) were in the IFU 2016 subgroup. Overall survival and freedom from aneurysm-related death estimates at 2 years were 90.9% and 97.6% in the IFU 2013 cohort (IFU 2016: 95.5% and 100.0%). The prevalence of complications seemed lower within IFU 2016 without significant differences. Conclusion: This study shows acceptable 2-year results of EVAS used within the IFU, without significant differences between the 2 IFU versions, though longer follow-up is indicated. The refined IFU significantly reduced the applicability of the technique.

Novel Endovascular Approach Using the Gore Iliac Branch Endograft for Short Iliac Anatomy

PURPOSE

To report the use of a branched iliac endograft to maintain internal iliac artery (IIA) patency in a patient with an infrarenal aortic aneurysm and short common iliac arteries (CIA).

CASE REPORT

A 74-year-old man presented with an asymptomatic, fusiform, 67-mm infrarenal aortic aneurysm confirmed on computed tomography. The right CIA was funnel shaped and only 15 mm in length, providing no appropriate stent-graft landing zone. The left CIA measured 14 mm in diameter and 25 mm in length. Endovascular repair of the aneurysm with preservation of the IIAs was achieved using a Gore Iliac Branch Endoprosthesis for the short right CIA and a conventional limb to land in the left CIA. Follow-up scans to 24 months have shown continued patency of the IIA and no evidence of endoleak.

CONCLUSION

The Gore Iliac Branch Endograft can be used to successfully treat patients with short CIA anatomy while preserving flow to the ipsilateral IIA, with maintained early patency of the IIA limb.

Determination of Stent Frame Displacement After Endovascular Aneurysm Sealing

Purpose: To describe and validate a new methodology for visualizing and quantifying 3-dimensional (3D) displacement of the stent frames of the Nellix endosystem after endovascular aneurysm sealing (EVAS). Methods: The 3D positions of the stent frames were registered to 5 fixed anatomical landmarks on the post-EVAS computed tomography (CT) scans, facilitating comparison of the position and shape of the stent frames between consecutive follow-up scans. Displacement of the proximal and distal ends of the stent frames, the entire stent frame trajectories, as well as changes in distance between the stent frames were determined for 6 patients with >5-mm displacement and 6 patients with <5-mm displacement at 1-year follow-up. The measurements were performed by 2 independent observers; the intraclass correlation coefficient (ICC) was used to determine interobserver variability. Results: Three types of displacement were identified: displacement of the proximal and/or distal end of the stent frames, lateral displacement of one or both stent frames, and stent frame buckling. The ICC ranged from good (0.750) to excellent (0.958). No endoleak or migration was detected in the 12 patients on conventional CT angiography at 1 year. However, of the 6 patients with >5-mm displacement on the 1-year CT as determined by the new methodology, 2 went on to develop a type Ia endoleak in longer follow-up, and displacement progressed to >15 mm for 2 other patients. No endoleak or progressive displacement was appreciated for the patients with <5-mm displacement. Conclusion: The sac anchoring principle of the Nellix endosystem may result in several types of displacement that have not been observed during surveillance of regular endovascular aneurysm repairs. The presented methodology allows precise 3D determination of the Nellix endosystems and can detect subtle displacement better than standard CT angiography. Displacement >5 mm on the 1-year CT scans reconstructed with the new methodology may forecast impaired sealing and anchoring of the Nellix endosystem.

Aortic Curvature Is a Predictor of Late Type Ia Endoleak and Migration After Endovascular Aneurysm Repair

Purpose: To evaluate the association between aortic curvature and other preoperative anatomical characteristics and late (>1 year) type Ia endoleak and endograft migration in endovascular aneurysm repair (EVAR) patients. Methods: Eight high-volume EVAR centers contributed 116 EVAR patients (mean age 81±7 years; 103 men) to the study: 36 patients (mean age 82±7 years; 31 men) with endograft migration and/or type Ia endoleak diagnosed >1 year after the initial EVAR and 80 controls without early or late complications. Aortic curvature was calculated from the preoperative computed tomography scan as the maximum and average curvature over 5 predefined aortic segments: the entire infrarenal aortic neck, aneurysm sac, and the suprarenal, juxtarenal, and infrarenal aorta. Other morphological characteristics included neck length, neck diameter, mural neck calcification and thrombus, suprarenal and infrarenal angulation, and largest aneurysm sac diameter. Independent risk factors were identified using backward stepwise logistic regression. Relevant cutoff values for each of the variables in the final regression model were determined with the receiver operator characteristic curve. Results: Logistic regression identified maximum curvature over the length of the aneurysm sac (>47 m−1; p=0.023), largest aneurysm sac diameter (>56 mm; p=0.028), and mural neck thrombus (>11° circumference; p<0.001) as independent predictors of late migration and type Ia endoleak. Conclusion: Aortic curvature is a predictor for late type Ia endoleak and endograft migration after EVAR. These findings suggest that aortic curvature is a better parameter than angulation to predict post-EVAR failure and should be included as a hostile neck parameter.

An optimized retroperitoneal approach for open aortic repair by partially removing the tenth rib without incising the pleura and diaphragm

The ninth intercostal thoracoretroperitoneal incision is the most common approach for open repair of suprarenal abdominal aortic aneurysm or abdominal aortic dissection, which necessitates incision of the pleura and diaphragm and may lead to cardiorespiratory distress postoperatively. We optimized this approach by partially removing the tenth rib, bluntly dissecting the diaphragm from its costal edge, and retracting the diaphragm superiorly. We successfully performed this approach in three patients with pararenal abdominal aortic aneurysm, abdominal aortic dissection, or renal artery aneurysm. Based on our experience, this approach allows easy exposure of the suprarenal aorta and avoids thoracotomy, which would potentially benefit patients' prognosis.

Endovascular vs Open AAA Repair: Does Size Matter?

Since the natural tendency of the aorta is to increase in diameter and tortuosity with age and since abdominal aortic aneurysms (AAAs) increase in diameter and length over time, encroaching on the renal and hypogastric orifices, early repair of AAAs (when =4.0 cm) may allow greater applicability of the endovascular option because of more favorable aortoiliac morphology. Patients who present at an older age with larger AAAs should be more likely to be anatomically excluded from endovascular AAA repair. Over a 42-month period, 317 consecutive patients referred with aortoiliac aneurysms (infrarenal AAA =4.0 cm) were evaluated by one of the authors (SGL) for endovascular vs open repair based on computed tomography (CT) and angiographic imaging. The 10 anatomic exclusion criteria were those applicable to the Zenith ® endograft (Cook, Inc), which currently is the most anatomically inclusive of the aortic endografts in commercial use in the United States. Based on their aortoiliac morphology, 212 patients were excluded from endovascular repair and 105 were included as acceptable anatomic candidates. Age, AAA size, and the reason(s) for exclusion were recorded for each patient. By use of Student's t test and logistic and linear regression analyses, the groups were compared by age, AAA size, and age + size. There was no significant difference in patient age or AAA size distribution between the group of patients excluded from endovascular repair based on aortoiliac morphology compared to those who met the inclusion criteria. Patients with small AAAs (4.0–5.4 cm) had similar age distribution as those with large (=5.5 cm) AAAs. The majority of patients (87%) were excluded based on proximal aortic neck morphology. The presence of aortoiliac morphology that precludes endovascular repair is independent of patient age or AAA size at presentation. A patient presenting with a small (4.0–5.4 cm) AAA is not more likely to be a candidate for endovascular repair than a patient with a large AAA.

Performance of the Endurant stent graft in challenging anatomy

OBJECTIVE

This study aimed to compare perioperative and postoperative outcomes after endovascular repair of abdominal aortic aneurysms (AAAs) in patients with various neck morphologic features.

METHODS

Data from the Endurant Stent Graft Natural Selection Global Postmarket Registry (ENGAGE) were used for the analyses. Patients were categorized into three different groups according to proximal aortic neck anatomy: regular (REG), intermediate (INT), and challenging (CHA). REG was defined as AAAs with a proximal neck ≥15 mm combined with a suprarenal angulation (α) ≤45 degrees and an infrarenal neck angulation (ß) ≤60 degrees. INT was defined as AAAs with a proximal neck of 10 to 15 mm combined with α ≤45 degrees and ß ≤60 degrees or with a proximal neck of >15 mm combined with α ≤60 degrees and ß = 60 to 75 degrees or α = 45 to 60 degrees and ß ≤75 degrees. CHA was defined as infrarenal necks that exceed at least one of the three defining factors.

RESULTS

Overall, 925 patients (75.9%) had REG anatomy, 189 patients (15.5%) had INT anatomy, and 104 patients (8.5%) had CHA anatomy. Patient demographics and risk factors were similar. There was a significant difference in AAA diameter between the REG and CHA groups (59.4 mm vs 65.2 mm; P < .001). Technical success was similar among groups (REG 99.1% vs INT 99.5% vs CHA 97.1%). There were no differences in mortality or the need for secondary procedures within 30 days or at 1 year. A significantly higher rate of type I endoleaks within 30 days was seen in CHA compared with REG (adjusted odds ratio, 0.15; 95% confidence interval, 0.05-0.46) and INT (adjusted odds ratio, 0.08; 95% confidence interval, 0.01-0.70), but there was no difference at 1-year follow-up.

CONCLUSIONS

This real-world, global experience shows promising results and indicates that endovascular AAA repair with the Endurant stent graft (Medtronic Vascular, Santa Rosa, Calif) is safe and effective in patients with challenging aortic neck anatomy. However, long-term follow-up of patients is required to confirm results.

Outcomes of endovascular aneurysm repair in patients with hostile neck anatomy

OBJECTIVES

This study aims to evaluate outcomes following EVAR in patients with hostile neck anatomy (HNA).

METHODS

Data prospectively collected from 552 elective EVARs were analysed retrospectively. Data regarding neck morphology was obtained from aneurysm stent plans produced prior to EVAR. HNA was defined as any of; neck diameter >28 mm, neck angulation >60°, neck length <15 mm, neck thrombus, or neck flare.

RESULTS

552 patients underwent EVAR. Mean age 73.9 years, mean follow-up 4.1 years. 199 patients had HNA, 353 had favourable neck anatomy (FNA). There was a significant increase in late type I endoleaks (FNA 4.5%, HNA 9.5%; P = 0.02) and total reinterventions (FNA 11.0%, HNA 22.8%; P < 0.01), and a significant decrease in late type II endoleaks in patients with HNA (FNA 16.7%, HNA 10.6%; P < 0.05). There was no significant difference in technical success (FNA 0.6%, HNA 2.0%; p = 0.12), 30-day re-intervention (FNA 2.8%, HNA 5.0%; P = 0.12), 30-day mortality (FNA 1.1%, HNA 0.5%; P = 0.45), 30-day type I endoleaks (FNA 0.8%, HNA 2.5%; P = 0.12), 5-year mortality (FNA 15.1%, HNA 14.6%; P = 0.86), aneurysm-related mortality (FNA 1.7% versus HNA 2.0%; P = 0.79), stent-graft migration (FNA 2.5%, HNA 3.0%; P = 0.75), sac expansion (FNA 13.0%, HNA 9.5%; P = 0.22), or graft rupture (FNA 1.1%, HNA 3.5%; P = 0.05). Binary logistic regression of individual features of HNA revealed secondary intervention (P = 0.009), technical failure (P = 0.02), and late type I endoleaks (P = 0.002), were significantly increased with increased neck diameter.

CONCLUSIONS

HNA AAAs can be successfully treated with EVAR. However, surveillance is necessary to detect and treat late type I endoleaks in HNA patients.

Correlation of CT aortography measurements of infrarenal aortic aneurysms and body mass index in preprocedural evaluation for endovascular repair

The aim of this study is to analyze the morphological differences of infrarenal aortic aneurysms and common iliac arteries that are important for endovascular management between patients of different body mass index using 64 slice multidetector row CT aortography. This was a multicenter study of 100 patients (50 Europeans and 50 Japanese). All patients had risk factors, manifest symptoms, and ultrasound verified aneurysmal dilation of the infrarenal aorta. All examinations were performed on the same CT platform using the same post-processing protocols. Due to the heterogeneity of the population, several statistical models were used. Significant differences were found in morphological parameters of infrarenal aorta in relation to BMI. In over one out of three patients with BMI less than 23, endovascular treatment is contraindicated due to the dimensions of the aneurysmal neck. Relative to BMI value, differences were found in transverse diameters of the medium part of the aneurysm and in the length of common iliac arteries. CT aortography performed on a 64 slice multidetector row CT platform provides precise and numerous data for the analysis of anatomical and pathological differences of infrarenal aortic aneurysms that are of crucial importance for the planning of treatment and the analysis of the differences relating to body habitus.

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.

Quantification of dilated infrarenal aorta by 64 multidetector computed tomographic evaluation in preventing EVAR complications in patients of different races

AIM

The hypothesis of this multicentric study is performing a specific typification in the selection of grafts for the endoluminal treatment of an aneurysmally altered distal aorta based on mathematical information and the correlation of a number of morphological parameters diagnosed by 64-multidetector computed tomographic (CT) aortography.

MATERIALS AND METHODS

The study is multicentric and encompassed 30 Asian and 30 European patients. Examinations were performed on the same type of 64- multidetector CT equipment and under same conditions of examination technique and postprocessing. Several statistical methods were applied to analyze the results.

RESULTS

Statistically significant differences were found between Asian and European patients in the morphology of the central part of the aneurysm at the level of the abdominal aorta and the width and length of the iliac arteries. The principal cause of the most frequent complication observed was defined by a CT aortographic study.

CONCLUSIONS

Computed tomographic aortographic quantification of significant parameters makes it possible to plan the exact dimensions of grafts in each individual case. Computed tomographic examinations make possible very exact measurements and positioning of the graft of the novel design proposed by the authors and expected to substantially reduce the incidence of complications.

Limited feasibility in endovascular aneurysm repair using currently available graft in Korea

Despite the wide acceptance of endovascular aneurysmal repair in patients with abdominal aortic aneurysm (EVAR), stringent morphologic criteria recommended by manufacturers may preclude this treatment in patients with AAA. The purpose of this study was to investigate how many patients are feasible by Zenith and Excluder stent graft system, which are available in Korea. Eighty-two AAA patients (71 men, mean age 70 yr) who had been treated surgically or medically from January 2005 to December 2006 were included. Criteria for morphologic suitability (MS) were examined to focus on characteristics of aneurysm; proximal and distal landing zone; angulation and involvement of both iliac artery aneurysms. Twenty-eight patients (34.1%) were feasible in Zenith stent graft and 31 patients (37.8%) were feasible in Excluder. The patients who were excluded EVAR had an average of 1.61 exclusion criteria. The main reasons for exclusion were an unfavorable proximal neck (n=34, 41.5%) and problem of distal landing zone (n=25, 30.5%). There was no statistical significance among gender, age or aneurysm size in terms of MS. Only 32 patients (39%) who had AAA were estimated to be suitable for two currently approved grafts by strict criteria. However, even unfavorable AAA patients who have severe co-morbidities will be included in EVAR in the near future. Therefore, more efforts including fine skill and anatomical understanding will be needed to meet these challenging cases.

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.

Influence of Infrarenal Neck Length on Outcome of Endovascular Abdominal Aortic Aneurysm Repair

PURPOSE

To evaluate the influence of the infrarenal neck length on clinical outcome after endovascular abdominal aortic aneurysm repair (EVAR).

METHODS

Data were analyzed from 3499 patients enrolled in the EUROSTAR registry between January 1999 and April 2005 who underwent EVAR with a Talent or Zenith endograft and had detailed morphological data recorded. The study cohort was divided into 3 groups according to infrarenal neck length: >15 mm (reference group A, n=2822), 11 to 15 mm (group B, n=485), and < or =10 mm (group C, n=192). Uni- and multivariate analyses were performed to evaluate differences in clinical outcomes among the study groups.

RESULTS

After correction for confounders, proximal type I endoleak within 30 days occurred in 10.9% of group C compared to 2.6% of group A (OR 4.46, 95% CI 2.61 to 7.61). Within 48 months of follow-up (median 12 months), the incidence of proximal endoleaks was higher in groups B (9.6%; HR 1.98, 95% CI 1.16 to 3.38) and C (11.3%; HR 2.132, 95% CI 1.17 to 4.60) compared to group A (3.4%).

CONCLUSION

Our study indicates that endovascular treatment of abdominal aortic aneurysms with infrarenal neck length <15 mm is associated with significantly increased risk of short- and midterm proximal endoleaks after EVAR. The greater risk of proximal endoleaks should be weighed against the risks of alternative treatment modalities.

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.

Reducing complications by better case selection: anatomic considerations

The feasibility of endovascular aortic aneurysm repair (EVAR) in any individual patient remains inherently dependent on the anatomy of the aorta and iliac arteries. There is a great deal of evidence in the literature that poor anatomic patient selection for EVAR will increase the risk of both procedure-related complications and compromised long-term outcomes. Inferior outcomes can include technical failures such as attachment-site endoleak, endograft migration, and ultimately aneurysm growth and rupture. Unfortunately, it is relatively rare to encounter a patient who possesses completely "ideal" anatomy for this technique. With the broadening spectrum of new devices applicable for the intraluminal treatment of abdominal aortic aneurysms, the vascular surgeon is challenged to be aware of individual selection criteria for the ever-widening variety of endoluminal grafts, in order to choose the optimal device for each patient's distinct anatomical situation. In patients who would otherwise be at high risk for traditional abdominal aortic aneurysm surgery based on medical comorbidities, the additional challenge for the practitioner who performs EVAR is to possess excellent judgment regarding just how far the anatomical "envelope" may be pushed without compromising patient outcomes.

Aortic Aneurysm Morphology in Asians:Features Affecting Stent-Graft Application and Design

PURPOSE

To determine the morphological features of abdominal aortic aneurysms (AAA) in an Asian cohort in order to identify unique features relevant to stent-graft planning and application.

METHODS

Spiral computed tomography (CT) and angiographic assessment of AAA morphology was performed on 65 ethnic Chinese (58 men; mean age 74 years, range 50-87) who underwent endovascular AAA repair. Morphological parameters were compared with published data from American and European patients. The eligibility and potential concerns referable to 4 current stent-graft designs were addressed.

RESULTS

Both common iliac arteries (CIA) measured significantly shorter in Asians, particularly on the right side. The mean RCIA and LCIA lengths were 29.9 mm and 34.2 mm, respectively (25.7 and 34.1 mm for CIAs <20 mm in diameter), compared to >50-mm in Caucasians (p<0.001). The distance between the lowest renal artery and the CIA bifurcation averaged 20 mm shorter in Asians: 148 mm on the right side and 153 mm for the left. The CIAs were also wider, averaging 20.2 mm for the right and 17.9 mm for the left. Other linear measurements did not show a population difference. The AAAs in this series were slightly larger (p<0.001), with a shorter neck (mean 23 mm, p<0.001). No correlation was found between the morphological parameters and body build. Internal iliac artery coverage with or without embolization was necessary in 51% of endovascular repairs due to short or aneurysmal CIAs.

CONCLUSIONS

These differences in AAA morphology pose unique challenges for endovascular repair in Asians. Preoperative angiography is more often necessary. The need for an accurate landing in a short CIA and insufficient length for maneuvering placed constraints on 2-piece graft designs with long main body lengths. A 3-piece endograft with wider aortic and iliac diameters is currently the most attractive option.