Predictive Factors, Morphologic Effects, and Proposed Treatment Paradigm for Type II Endoleaks after Repair of Infrarenal Abdominal Aortic Aneurysms

Incidence and Risk Factors for Sac Expansion after Endovascular Aneurysm Repair of Abdominal Aortic Aneurysms

Purpose

This study aimed to examine the sac changes after endovascular aneurysm repair (EVAR) in patients with abdominal aortic aneurysms.

Methods

Materials and We examined the aneurysm sac size initially and regularly after surgery in 157 consecutive patients who underwent EVAR in 2009-2019. Contrast-enhanced computed tomography (CT) scans were used as well as ultrasound images with non-enhanced CT scans in the patients with renal insufficiency. Sac expansion (SE) at 3 years was divided into two categories: progressive SE (PSE) defined as continuous sac enlargement of ≥5 mm on serial follow-up images at 1 and 3 years compared with the initial sac and delayed SE (DSE) defined as re-expansion of ≥5 mm compared with the regressed or stable sac at 1 year. The SE rate at 1 and 3 years and the risk factors for SE at 3 years were analyzed using logistic regression.

Results

During a median follow-up of 32.5 months, nine reinterventions in six patients were performed with open conversion (n=5) and endovascular repair (n=4). At 1 year, 112 patients underwent follow-up imaging. SE and sac regression were noted in 4 (3.6%) and 57 (50.9%) patients, respectively. Of the 64 patients with 3-year follow-up images, 16 (25%) exhibited SE (PSE [n=6] and DSE [n=10]). In the multivariable analysis, the risk factors for overall SE at 3 years were endoleaks at 1 year (P=0.006) and renal insufficiency (P=0.003).

Conclusion

During post-EVAR follow-up, patients with any endoleak at 1 year or renal insufficiency must be strictly monitored for SE development.

Midterm Outcomes of Endovascular Abdominal Aortic Aneurysm Repair with Prevention of type 2 Endoleak by Intraoperative Aortic Side Branch Coil Embolization

OBJECTIVE

The midterm results of endovascular abdominal aortic aneurysm repair (EVAR) with aortic side branch coil embolization during EVAR was evaluated.

METHODS

Our center began coil embolization for all patent inferior mesenteric artery (IMA) and lumbar artery (LA) with an inner diameter more than 2.0 mm during EVAR since June 2015. When four or more LA were patent, coil embolization for LA with inner diameter 2.0 mm or less was done. EVAR without aortic side branches coil embolization was performed for 59 patients prior to June 2015 (control group) and 79 patients underwent EVAR with coil embolization during EVAR (coil group). The success rate of coil embolization for IMA and LA was evaluated in coil group. The frequency of type 2 endoleak (T2EL), freedom from aneurysm sac expansion (5 mm or more) rate and the rate of the aneurysm sac shrinkage (10 mm or more) were compared between the coil and control groups. Additionally, multiple logistic regression analysis for all patients was conducted to analyze whether IMA patency and the number of patent lumbar artery at the end of EVAR were the risk factors of the aneurysm sac expansion of 5 mm or more.

RESULTS

The success rate of IMA coil embolization was 96.4% and that of LA was 74.5%. Compared to the control group, the frequency of T2EL was significantly lower in coil group at 7 days (1.3% vs. 60.4%, P <0.0001) and at 6 months (2.1% vs 38.2%, P <0.0001) after EVAR. The freedom from aneurysm sac expansion rate was significantly better in the coil group at 5 years (100% in coil group and 65.2% in control group, P = 0.002). The rate of aneurysm sac shrinkage was significantly better in coil group (15.5% vs. 2.0% at 1 year, 42.8% vs. 6.3% at 2 years and 53.4% vs. 17.8% at 3 years, p = 0.0007). The risk of aneurysm sac expansion of 5 mm or more was estimated to be 11 times greater when the IMA was patent, and 4.9 times greater when 3 or more LAs were patent at the end of EVAR.

CONCLUSION

When IMA was occluded and the number of patent LA became 2 or less by aortic side branch coil embolization during EVAR, favorable mid-term results were safely obtained and good long-term result could be expected with EVAR.

Short-Term Re-intervention of Endovascular Abdominal Aortic Aneurysm Repair

Background and aim

Endovascular aneurysm repair (EVAR) has revolutionized the management of abdominal aortic aneurysm (AAA). The re-intervention rate following EVAR has been a subject of debate in many studies. The study aims to evaluate the short-term outcomes in terms of the early (four-year) re-intervention rate following EVAR at our centre and compare it to the average re-intervention rate of the main studies assessed by the National Institute of Health and Care Excellence (NICE).

Methods

The EVAR procedures performed over two years (2015 and 2016) were retrieved using the operation codes. The clinical portal and PACS systems were used to review the discharge summaries, clinic and multidisciplinary team (MDT) letters, as well as the scans and interventional radiology procedures to assess the patients’ adherence to follow-up and identify any re-intervention procedure done to correct underlying problems related to the EVAR performed. Patients who switched their follow-up to another hospital were contacted and interviewed about any re-intervention undergone. 

Results

A total of 108 patients underwent EVAR during the two-year study period. Twenty EVAR-related re-interventions (18.5%) were recorded, irrespective of the cause or the type of intervention. This is slightly higher than the average rate by NICE (16.89%). Type 1 endoleak represented the leading cause for re-intervention (30%). Most of the cases of re-intervention were done endovascularly (60%). Forty-five percent of the patients had a re-intervention during the first year and 35% in the third year.

Conclusion

This study shows that although our re-intervention rate following EVAR was slightly higher than the international average, EVAR is still a safe method for the repair of AAA with relatively low peri-operative morbidity and mortality. However, long-term follow-up of these patients is mandatory as re-interventions are frequently required. Nonetheless, the majority of re-interventions can be done with minimal morbidity to the patient.

A Systematic Review and Pooled Meta-Analysis on the Incidence and Temporal Occurrence of Type II Endoleak Following an Abdominal Aortic Aneurysm Repair

BACKGROUND

The aim in this study was to systematically review the literature to identify the time of occurrence of a newly diagnosed Type II endoleak (T2E) following an endovascular aneurysm repair (EVAR) for an infrarenal abdominal aortic aneurysm (AAA) and its potential impact on aneurysmal sac diameter changes.

METHODS

A comprehensive systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Eligible studies were identified through a search of PubMed, Scopus and Cochrane until January 2020. A meta-analysis was conducted with the use of a random effects model. The I-square statistic was used to assess for heterogeneity.

RESULTS

Thirty-three observational studies were deemed eligible and provided data for 2643 T2E detected following EVAR. A total of 1432 (54.2%) T2E were diagnosed before 30 days follow-up, while 1035 (39.1%) T2E were diagnosed beyond 30 days following EVAR. A total of 222 (8.4%) T2E were diagnosed after 12 months of follow-up. A pooled meta-analysis of 6 studies, showed that early diagnosed T2E had a statistically significant higher odds of resolving as compared to those detected late (OR: 2.41; 95% CI: 1.14-5.09; P = 0.021; I² = 68.9%). Sac expansion was documented in 313 (29%) T2E. The ruptured endoleaks were 14 (1.1%).

CONCLUSIONS

The occurrence of a T2E is a dynamic process detected throughout the lifetime of a patient with 8% detected beyond 12 months following EVAR. Long-term follow up is required with future prospective studies with consist reporting on changes in sac diameter, the thrombus characteristics. Long-term outcomes are needed to optimize management of patients with a newly diagnosed T2E.

Factors Influencing Clinical Success Following Endovascular Treatment of Type II Endoleaks

PURPOSE

To compare long-term outcomes of transarterial (TA) and translumbar (TL) embolization of type II endoleaks (T2E) following EVAR, as well as factors that predict clinical success.

METHODS

129 (mean age, 71.4y; range, 53-95) with T2E referred for embolization from August-2003 to December-2017 were retrospectively reviewed. One-hundred-eighty procedures were performed via TA (n = 139) and TL (n = 41) approaches, with 37 patients undergoing 51 reinterventions. Clinical success was defined as absence of endoleak and/or absence of aneurysm sac enlargement on follow-up imaging. Medical comorbidities, procedural data, embolic agents used, presence of successful sac embolization, and 30-day morbidity and mortality data were collected.

RESULTS

TL approaches had higher technical success (41/41 vs.122/139, p = .014). Clinical success rates were 52% (N = 58/111) and 62% (N = 23/37) for TA and TL procedures respectively (p = .34). Looking at all procedures, sac embolization using n-butyl cyanoacrylate glue had higher clinical success compared to other embolic agents (p = .017-.037). Successful sac access was a strong predictor of success for TA procedures (46/78 vs.12/33, p = .0379). 30-day complication rates were similar between TA (5.8%) and TL (4.9%) approaches. There was 1 death secondary to graft infection following TA embolization.

CONCLUSIONS

Overall clinical success of TA and TL embolization when considering re-interventions is high. n-butyl cyanoacrylate glue had significantly higher success than other embolic agents (p = .017-.037). Successful sac access was associated with success for TA procedures.

Predictive Factor of the Possibility for Aortic Side Branches Coil Embolization during Endovascular Abdominal Aortic Aneurysm Repair

Objective: Coil embolization of aortic side branches has been additionally performed to prevent type II endoleak during EVAR in our institute. In this study, we evaluated the predictive factors of the possibility for coil embolization of the inferior mesenteric artery (IMA) and lumbar artery (LA) during EVAR.

Methods: Seventy-four EVAR patients during June 2015 and April 2019 were included in the study. The coil embolization procedural time for one vessel is limited to 10 min. Aortic side branches were selected with 4 Fr Shepherd hook type catheter (Medikit, Tokyo, Japan) and were embolized with Interlock (Boston Scientific, MA, USA) via microcatheter. As predictive factors, internal diameter of aortic side branches and the aortic diameter perpendicular to the origin of LA (aortic diameter) were evaluated.

Results: Coil embolization was tried for 52 patent IMAs and all IMAs except two IMAs with ostial stenosis were successfully coil embolized (96.2%). Totally 190 LAs were patent and coil embolization was tried for 144 LAs. Among 144 LAs, 106 LAs (73.6%) were successfully coil embolized and the diameter was significantly longer (2.30±0.51 mm vs. 2.04±0.41 mm, p=0.007) and aortic dimeter was significantly shorter (30.0±8.1 mm vs. 40.5±11.6 mm, p<0.001) in successfully embolized LAs. Cut off value of successful LA coil embolization was 2.06 mm for internal diameter and 36.1 mm for aortic diameter by receiver operating characteristic curve analysis. Successful coil embolization rate for LAs with internal diameter longer than 2.0 mm and aortic diameter less than 36.2 mm was 90% (72 among 80 LAs).

Conclusion: Coil embolization during EVAR for IMA was highly successful, if there was no calcified ostial stenosis. LA embolization was feasible especially for LAs with internal diameter ≥2.0 mm and aortic diameter ≤36.1 mm. This information would be useful to select the target vessel for aortic side branches coil embolization during EVAR. (This is a translation of Jpn J Vasc Surg 2019; 28: 389–396.)

Multicentre randomised controlled trial to evaluate the efficacy of pre-emptive inferior mesenteric artery embolisation during endovascular aortic aneurysm repair on aneurysm sac change: protocol of Clarify IMA study

INTRODUCTION

Type II endoleak (EL) is frequently seen after endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA) and is often considered responsible for aneurysm sac enlargement if it persists. In order to reduce type II EL and consequent sac enlargement, pre-emptive embolisation of the inferior mesenteric artery (IMA), which is a main source for persistent type II EL, has been introduced in many vascular centres. At present, there is a lack of robust evidence to support the efficacy of pre-emptive embolisation of IMA on reduction of persistent type II EL with subsequent sac shrinkage.

METHOD AND ANALYSIS

This multicentre, randomised controlled trial will recruit 200 patients who have fusiform AAA ≥50 mm/rapidly enlarging fusiform AAA, with patent IMA, and randomly allocate them either to a pre-emptive IMA embolisation group or non-embolisation control group in a ratio of 1:1. The primary endpoint is the difference of aneurysm sac volume change assessed by CT scans between the pre-emptive IMA embolisation group and the control group at 12 months after EVAR. The secondary endpoints are defined as change of aneurysm sac volume in both groups at 6 and 24 months, freedom from sac enlargement at 12 and 24 months after EVAR, prevalence of type II EL at 1, 6, 12 and 24 months evaluated by contrast-enhanced CT, reintervention rate, aneurysm related mortality, overall survival, perioperative morbidity, volume of contrast media used during EVAR and dosage of radiation.

ETHICS AND DISSEMINATION

The protocol has been reviewed and approved by the ethics committee of Nara Medical University (No. 2113). The findings of this study will be communicated to healthcare professionals, participants and the public through peer-reviewed publications, scientific conferences and the University Hospital Medical Information Network Clinical Trials Registry home page.

TRIAL REGISTRATION NUMBER

UMIN000035502.

Machine deep learning accurately detects endoleak after endovascular abdominal aortic aneurysm repair

Objective

The objective of this study was to develop a machine deep learning algorithm for endoleak detection and measurement of aneurysm diameter, area, and volume from computed tomography angiography (CTA).

Methods

Digital Imaging and Communications in Medicine files representing three-phase postoperative CTA images (N = 334) of 191 unique patients undergoing endovascular aneurysm repair for infrarenal abdominal aortic aneurysm (AAA) with a variety of commercial devices were used to train a deep learning pipeline across four tasks. The RetinaNet object-detection convolutional neural network (CNN) architecture was trained to predict bounding boxes around the axial CTA slices that were then stitched together in two dimensions into a smaller region containing the aneurysm. Multiclass endoleak detection and segmentation of the AAA, endograft, and endoleak were performed on this smaller region. Segmentations on a single randomly selected contrast from each scan included 33 full and 68 partial segmentations for endograft and AAA and 99 full segmentations for endoleak. A modified version of ResNet-50 CNN was used to detect endoleak on individual axial slices. A three-dimensional U-Net CNN model was trained on the task of dense three-dimensional segmentation and used to measure diameter and volume with a specially designed loss function. We made use of fivefold cross-validation to evaluate model performance for each step, splitting training and testing data at each fold, such that multiple scans from the same patient were preserved with the same fold. Algorithm predictions for endoleak were compared with the radiology report and with a subset of CTA images independently read by two vascular specialists.

Results

The localization portion of the network accurately predicted a region of interest containing the AAA in 99% of cases. The best model of binary endoleak detection obtained an area under the receiver operating characteristic curve of 0.94 ± 0.03 with an optimized accuracy of 0.89 ± 0.03 on a balanced data set. An introduced postprocessing algorithm for determining maximum diameter was used on both the predicted AAA segmentation and ground truth segmentation, predicting on average an absolute diameter error of 2.3 ± 2.0 mm by 1.4 ± 1.7 mm for each measurement, respectively. The algorithm measured AAA and endograft volume accurately (Dice coefficient, 0.95 ± 0.2) with an absolute volume error of 10.1 ± 9.1 mL. The algorithm measured endoleak volume less accurately, with a Dice score of 0.53 ± 0.21 and an average absolute volume error of 1.2 ± 1.9 mL.

Conclusions

This machine learning algorithm shows promise in augmenting a human's ability to interpret postoperative CTA images and may help improve surveillance after endovascular aneurysm repair. External validation on larger data sets and prospective study are required before the algorithm can be clinically applicable.

This manuscript describing the application of machine learning for endoleak has clinical relevance to endovascular abdominal aortic aneurysm follow-up. The techniques described herein may be more broadly applied to the diagnosis of aortic disease. In the future, vascular surgeons will benefit from integrating such artificial intelligence algorithms into their practice.

Type II endoleak model creation and intraoperative aneurysmal sac embolization with n-butyl cyanoacrylate-lipiodol-ethanol mixture (NLE) in swine

Background

The purpose of this study was to evaluate the feasibility of type II endoleak model creation and efficacy of intraoperative aneurysmal sac embolization using n-butyl-2-cyanoacrylate-lipiodol-ethanol mixture (NLE) for type II endoleak in swine.

Methods

In six swine (mean body weight 53.5 kg), abdominal aortic aneurysm (AAA) was created and then end-to-side anastomosis between the left renal artery and AAA sac was performed. And then, endovascular abdominal aortic aneurysm repair (EVAR) was performed, leading to creation of a type II endoleak model. As control group, EVAR without sac embolization was performed in two swine. In four swine, AAA sac was embolized using NLE immediately after EVAR via the microcatheter placed in AAA sac (NLE embolization group). Follow-up aortography was performed immediately and three days after the procedure, and then the aneurysms were extracted.

Results

The AAA sac and type II endoleak model were successfully created in all cases. In control group, type II endoleak persisted three days after the procedure. In NLE embolization group, endoleak disappeared immediately and three days after the procedure. In NLE embolization group, AAA sac was occupied with thrombus and embolic material. Inflammatory changes were recognized in aneurysmal sac wall in NLE embolization group.

Conclusions

This experimental study suggests that creation of a type II endoleak model in swine is feasible and that intraoperative AAA sac embolization with NLE during EVAR might reduce the occurrence of type II endoleak.

Editor's Choice - Systematic Review and Meta-Analysis of the Outcome of Treatment for Type II Endoleak Following Endovascular Aneurysm Repair

OBJECTIVES

The efficacy and need for secondary interventions for type II endoleaks following endovascular abdominal aortic aneurysm repair (EVAR) remain controversial. This systematic review aimed at investigating the clinical outcomes of different type II endoleak treatments in patients with a persistent type II endoleak after EVAR.

DATA SOURCES

Embase, Medline via Ovid, Web of Science Core Collection, the Cochrane CENTRAL, and Google Scholar.

REVIEW METHODS

This systematic review was performed in accordance with the PRISMA Statement. Outcomes of interest were technical and clinical success, change in sac diameter, complications, need for additional interventions, abdominal aortic aneurysm (AAA) rupture, and (AAA related) mortality. Meta-analyses were performed with random effects models.

RESULTS

A total of 59 studies were included, with a cumulative cohort of 1073 patients with persistent type II endoleak. Peri-operative complications following treatment of type II endoleaks occurred in 3.8% of patients (95% CI 2.7-5.2%), and AAA related mortality was 1.8% (95% CI 1.1-2.7%). Overall technical success was 87.9% (95% CI 83.1-92.1%), while clinical success was 68.4% (95% CI 61.2-75.1%). Among studies detailing sac dynamics, decrease or stable sac, with or without resolution, was achieved in 78.4% (95% CI 70.2-85.6%). Changes in sac diameter following type II endoleak treatment were documented in 157 patients to at least 24 months. Within this group an actual decrease in sac diameter was reported in only 27 of 40 patients.

CONCLUSION

There is little evidence supporting the efficacy of secondary intervention for type II endoleaks after EVAR. Although generally safe, the lack of evidence supporting the efficacy of type II endoleak treatment leads to difficulty in assessing its merits.

AAA Rupture and Psoas Hematoma due to Type II Endoleak from Inferior Mesenteric Artery "Unusual" Collaterals

Although endovascular aneurysm repair (EVAR) in the abdominal aorta has reduced the perioperative mortality when compared with open repair, the need for reintervention after complications such as endoleak may be presented in up to 20% of the cases. Type II endoleak from branch vessels is often benign but can potentially be associated with progressive abdominal aortic aneurysm growth and sac expansion. We present a rare case of a patient who presented with sac expansion and psoas hematoma due to Type II endoleak from "unusual" collaterals of IMA and was treated successfully with endoleak microembolization and percutaneous decompression of the hematoma.

Direct sac puncture versus transarterial embolization of type II endoleaks: An evaluation and comparison of outcomes

Purpose To determine the outcomes of type II endoleak embolization with aneurysm sac obliteration and whether the approach - direct sac puncture or transarterial - affects outcome. Methods A retrospective review of patients who underwent endovascular aneurysm repairs and subsequent type II endoleak embolization over 10 years was performed. Twenty-three patients (median age: 73 years, range: 40-88 years) underwent 35 embolizations. Embolization was performed with the goal of obliterating both the endoleak sac and feeding vessels. Embolization agents used include cyanoacrylate glue only (48%), glue and coils (36%), coils only (13%), and other (3%). Results Mean follow-up was 21.8 months. Patients underwent an average of 1.5 embolizations, with 35% requiring more than one. Technical success rate was 89%. Freedom from aneurysm sac expansion was achieved in 91%. Freedom from type II endoleak was accomplished in 70%. There were no ruptured aneurysms during the follow-up period. Direct sac puncture and transarterial approaches had similar incidences of aneurysm sac growth ( p = 0.74), persistent type II endoleak ( p = 0.32), and complications ( p = 0.64). However, direct sac puncture had significantly shorter fluoroscopy ( p < 0.001) and total procedure times ( p < 0.001) than transarterial embolizations. Conclusion Direct sac puncture and transarterial embolization of type II endoleak with aneurysm sac obliteration are similarly effective for the prevention of aneurysm sac growth. However, direct sac puncture is our preferred approach given its significantly shorter fluoroscopic and procedural times.

One Year Outcome Using Newer Generation Endografts: A National Multicenter Study on Real Word Practice

BACKGROUND

The aim of this study was to assess the 1 year outcomes following endovascular aortic aneurysm repair (EVAR) with the use of newer generation endografts.

METHODS

Retrospective analysis was conducted of prospectively collected multicenter data from 385 EVARs. Newer endografts were defined as those introduced after 2004. Patients' demographics and comorbidities, type of operation, and abdominal aortic aneurysm (AAA) morphological characteristics were analyzed. Computer tomography was performed 1 month and 1 year post-EVAR.

RESULTS

Mean age of the patients was 71.3 years; in 335 cases the intervention was elective. The mean AAA sac, neck diameter, and length were 57.15, 24.5, and 28.97 mm, respectively. Ninety-four endoleaks were recorded in 92 patients (25%), including 11 type 1a (T1aE), 3 type 1b, and 78 type 2 (T2E) endoleaks. On logistic regression analysis, neck diameter >30 mm (P = 0.032) and initial AAA sac diameter >55 mm (P = 0.031) were associated with T1aE. No association was found with T2E. Overall, 107 (27%) patients had sac expansion at 1 year associated with the presence of T2E (P = 0.019). No association was observed between T1aE or T2E and specific endograft.

CONCLUSIONS

Newer generation endografts show very satisfactory performance even in difficult anatomies. T1aE was associated with initial sac and neck diameter, while AAA sac expansion was associated with the presence of T2E.

The Influence of Preoperative Aneurysmal Thrombus Quantity and Distribution on the Development of Type II Endoleaks with Aneurysm Sac Enlargement After EVAR of AAA

PURPOSE

To determine the influence of preoperative aneurysmal thrombus quantity and distribution on the development of type II endoleak with aneurysm sac enlargement after endovascular aneurysm repair (EVAR).

MATERIALS AND METHODS

We retrospectively analyzed the pre- and postoperatively performed CT scans of 118 patients who had follow-up imaging for at least 1 year after EVAR available. We assessed preoperative thrombus perimeter (T Peri), diameter (T Dia), cross-sectional area (T CSA), and volume (T Vol). The preoperative thrombus distribution was classified into no thrombus, semilunar-shaped (anterior, right side, left side, posterior) thrombus, and circumferential type thrombus. The number of preoperative patent aortic side branches (ASB) was identified. Endpoint was type II endoleak with aneurysm volume (A Vol) increase of ≥5 % during follow-up.

RESULTS

During follow-up (2 years, range 1-9 years), 17 patients with type II endoleak had significant A Vol increase. Less preoperative T Peri, T Dia, T CSA, and T Vol were associated with A Vol increase. A circumferential thrombus distribution significantly protected against aneurysm enlargement (p = 0.028). The variables with the strongest significance for A Vol increase were preoperative T Vol/A Vol ratio (OR 0.95; p = 0.037) and number of patent ASB (OR 3.52; p < 0.001).

CONCLUSION

A low preoperative T Vol/A Vol ratio and a high number of patent ASB were associated with aneurysm sac enlargement after EVAR.

Predictive Factors for Type II Endoleaks after Treatment of Abdominal Aortic Aneurysm by Conventional Endovascular Aneurysm Repair

BACKGROUND

The aim of this study was to identify the predictive factors for the development of type II endoleaks (EL-II) after endovascular aneurysm repair (EVAR).

METHODS

We assessed the preoperative and postoperative computed tomography data of 308 patients who underwent EVAR between 2000 and 2012 and in 84 of whom primary or secondary EL-II occurred. The data analyzed were: demographics, number and diameter of lumbar arteries (LAs), inferior mesenteric artery (IMA), median sacral artery (MSA), accessory renal arteries (ARas), maximum diameter of infrarenal abdominal aortic aneurysm, diameter and length of proximal aortic neck. Statistical analysis was performed using Stata software (version 12). Categorical parameters were compared between groups using chi-squared or Fisher's exact tests as appropriate. Continuous variables were analyzed using Student's t-test or Mann-Whitney test as appropriate (normality studied by the Shapiro-Wilk and homoscedasticity verified using the Fisher-Snedecor test).

RESULTS

Of the 308 patients included (mean age, 73.8 ± 8.74 years), 284 (92%) were men, 61 (20%) were smokers, 113 (37%) had chronic obstructive pulmonary disease, 215 (70%) were taking antiplatelet. Respectively, 13, 51, 60, 103, 28, 40, 2, and 7 patients had 1, 2, 3, 4, 5, 6, 7, and 8 patent LAs. Before surgery, 221 IMAs and 136 MSA were patent. The sources of EL-II were: LA (n = 51), IMA (n = 22), MSA (n = 1), IMA and LA (n = 8), IMA and ARa (n = 1), and unknown (n = 1). Logistic regression models adjusting for clinically relevant covariables (age, American Society of Anesthesiologists, smoking status, dyslipidemia, and diuretics) were proposed to study morphologic EL-II predictive factors, first in the entire population, and then in the more specific population for whom IMA was patent. Risk factors of occurrence EL-II were: permeability of the IMA (70 patients [83%] vs. 155 [69%], P = 0.01), IMA diameter (3.49 mm vs. 2.71 mm, P < 0.001), number of LAs patent higher than or equal to 4 (P < 0.001), the mean LA diameter greater than 2.4 mm (P < 0.001), and MSA diameter (2.28 mm vs. 1.94 mm; P < 0.01).

CONCLUSIONS

Our results show the major role of the number and diameter of the patent aortic branches in the development of EL-II. As they can result in complications increasing the morbidity and mortality after EVAR, it is relevant to identify the risk factors of their occurrence.

Embolization by micro navigation for treatment of persistent type 2 Endoleaks after endovascular abdominal aortic aneurysm repair

Background:Endovascular repair has become established as a safe and effective method for treatment of abdominal aortic aneurysms. One major complication of this treatment is leakage, or endoleaks, of which type 2 leaks are the most common.Objective:To conduct a brief review of the literature and evaluate the safety and effectiveness of embolization by micronavigation for treatment of type 2 endoleaks.Method:A review of medical records from patients who underwent endovascular repair of abdominal aortic aneurysms identified 5 patients with persistent type 2 endoleaks. These patients were submitted to embolization by micronavigation.Results:In all cases, angiographic success was achieved and control CT scans showed absence of type 2 leaks and aneurysm sacs that had reduced in size after the procedure.Conclusion:Treatment of type 2 endoleaks using embolization by micronavigation is an effective and safe method and should be considered as a treatment option for this complication after endovascular repair of abdominal aortic aneurysms.

CT features of early type II endoleaks after endovascular repair of abdominal aortic aneurysms help predict aneurysm sac enlargement

PURPOSE

To determine computed tomographic (CT) features of early type II endoleaks associated with aneurysm sac enlargement after endovascular aortic aneurysm repair (EVAR) of abdominal aortic aneurysm.

MATERIALS AND METHODS

Institutional review board approval was not required for this retrospective study. The authors reviewed imaging and clinical data from 56 patients (seven women, 49 men; mean age ± standard deviation, 71 years ± 7.9; age range, 52-85 years) with early type II endoleak who had undergone EVAR between December 2002 and December 2011 and who had been followed up with imaging and clinical evaluation for at least 6 months. The number and diameter of all feeding and/or draining arteries were measured, and endoleaks were classified according to their sources into simple inferior mesenteric artery (IMA), simple lumbar artery (LA), complex LA, and complex IMA-LA type II endoleaks. Volume and attenuation of the nidus were measured. Aneurysm enlargement was defined as an increase in the aneurysm volume of more than 5% during follow-up. Simple and multivariate logistic regression analyses were performed to identify independent clinical and imaging variables associated with aneurysm enlargement.

RESULTS

Twenty-three of the 56 patients (41%) showed aneurysm sac enlargement during follow-up (mean follow-up, 3.0 years ± 2.0). With the multivariate model, the variables that showed the strongest indicators for aneurysm sac enlargement were complex IMA-LA type II endoleak (odds ratio [OR] = 10.29, P = .004) and the diameter of the largest feeding and/or draining artery (OR = 4.55, P = .013). Patients without complex IMA-LA type II endoleak in whom the largest feeding and/or draining artery was larger than 3.8 mm and patients with a complex IMA-LA type II endoleak in whom the largest feeding and/or draining artery was larger than 2.2 mm were at high risk for aneurysm sac enlargement.

CONCLUSION

The strongest indicators for aneurysm sac enlargement are complex IMA-LA type II endoleak and the diameter of the largest feeding and/or draining artery.

Outcomes of percutaneous endovascular intervention for type II endoleak with aneurysm expansion

OBJECTIVE

Type II endoleak (T2EL) with aneurysm expansion is believed to place patients at risk for aneurysm-related mortality (ARM). Treatment with glue and/or coil embolization of the aneurysm sac, inferior mesenteric artery (IMA), and lumbar branches via translumbar or transarterial approaches has been utilized to ablate such endoleaks, and thus decrease ARM. We evaluated the midterm results of percutaneous endovascular treatment of T2EL with aneurysm expansion.

METHODS

Single-institution, 5-year (January 2003 to August 2008) retrospective study of all endovascular interventions for T2EL with sac expansion. Blinded, independent review of all available pre- and post-T2EL intervention computed tomography (CT) scans was performed. Aneurysm sac maximal transverse diameters and aneurysm sac growth rates prior to and following T2EL intervention were analyzed.

RESULTS

Forty-two patients (34 male, eight female; mean age, 75) underwent T2EL intervention at 26 ± 20 months after endovascular aneurysm repair (EVAR) and were subsequently followed for 23 ± 20 months. Seven out of 42 patients (17%) underwent repeat T2EL intervention. Interventions included 44 translumbar sac embolizations, and transcatheter embolizations of nine IMAs and seven lumbar/hypogastric arteries. Aneurysm diameter was 6.1 ± 1.6 cm at EVAR, 6.6 ± 1.5 cm at initial T2EL treatment, and 6.9 ± 1.7 cm at last follow-up. There were no significant differences in the rates of aneurysm sac growth pre- and post-T2EL treatment. At last follow-up imaging, recurrent or persistent T2EL was noted in 72% of patients. Of 42 patients, nine (21%) received operative endoluminal correction of occult type I or type III endoleaks that were diagnosed during the T2EL angiographic intervention. There were no aneurysm ruptures or ARMs during follow-up; overall mortality for the 5-year study period was 24%.

CONCLUSIONS

In this series, percutaneous endovascular intervention for type II endoleak with aneurysm sac growth does not appear to alter the rate of aneurysm sac growth, and the majority of patients display persistent/recurrent endoleak. However, diagnostic angiographic evaluation may reveal unexpected type I and III endoleaks and is therefore recommended for all patients with T2EL and sac growth. While coil and glue embolization of aneurysm sac and selected branch vessels does not appear to yield benefit in our series, the diagnosis and subsequent definitive treatment of previously occult type I and III endoleaks may explain the absence of delayed rupture and ARM in our series.

Type 2 endoleak embolization comparison: translumbar embolization versus modified transarterial embolization

PURPOSE

To evaluate the success of endoleak repair using translumbar (TL) endoleak embolization compared with a transarterial (TA) technique that involves embolization of the endoleak cavity itself in addition to the feeding artery.

MATERIALS AND METHODS

Eighty-four patients (mean age, 78.2 years; age range, 58-94 years) with type 2 endoleaks were included in this retrospective study. Patients underwent either TL endoleak embolization or TA embolization between January 2002 and December 2007. TA embolization involved entering the endoleak cavity through the inferior mesenteric or lumbar artery. Both the endoleak cavity and the feeding artery were then embolized by using coils through a microcatheter. TL embolizations were performed by using standard technique with coils and n-butyl cyanoacrylate as the embolization agents. Clinical success was defined as the absence of an endoleak and/or aneurysm enlargement at follow-up CT angiography. Statistical comparison was performed with the Fisher exact test.

RESULTS

Endoleak repair was successful in 72% (45/62) of the TL embolizations and 78% (18/23) of the TA embolizations, with a mean follow-up of 18.7 months (range, 1-84 months). There was no significant difference in clinical success between the two groups (P = .41). There were two (3.2%) complications in the TL group and no complications in the TA group.

CONCLUSIONS

The effectiveness of the TA endoleak embolization technique, which involves embolizion of the endoleak cavity and the feeding artery, is similar to that of TL embolization for treatment of type 2 endoleaks.

Effect of Systemic Blood Pressure on Aneurysm Size in the Presence of a Type II Endoleak

The objective of this study was to determine whether hypertension is a risk factor for aneurysm enlargement in patients with an untreated type II endoleak after endovascular abdominal aortic aneurysm repair (EVAR). Between January 2000 and December 2005, 296 patients underwent elective EVAR using a bifurcated Zenith stent graft. Forty-nine (17%) patients had a type II endoleak triaged to observation. Patient clinical data and data on endoleak status, aneurysm size, and endoleak intervention were collected prospectively. Aneurysm size remained the same or decreased in 39 of 49 (80%) patients. In the remaining 10 (20%) patients with aneurysm enlargement, 7 required intervention. There was no difference in initial aneurysm size, patient age, gender, or comorbidities between patients with enlarging aneurysms and those with stable or regressing aneurysms. However, patients with enlarging aneurysms had a mean systolic blood pressure (SBP) of 144 ± 14 mm Hg compared with 136 ± 13 mm Hg for patients with stable or regressing aneurysms ( p = .08). Multivariate regression analysis demonstrated increased SBP to be an independent predictor of aneurysm enlargement ( p = .05). Patients with systolic hypertension and an untreated type II endoleak are more likely to demonstrate aneurysm enlargement after EVAR. Aggressive blood pressure control may be an important adjunct in the management of patients with type II endoleak after EVAR.