Are type II (branch vessel) endoleaks really benign?

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.

Type II Endoleak Nidus Volume on Arterial and Delayed Phases of Initial CT Angiography after Endovascular Abdominal Aortic Aneurysm Repair Predicts Persistent Endoleak and Aneurysm Sac Enlargement

Purpose

To evaluate type II endoleak nidus volume (ENV) in the arterial phase (ENV_AP) and delayed phase (ENV_DP) of the first postoperative CT angiography (CTA) as a predictor of persistent endoleak and aneurysm sac enlargement at follow-up CTA in patients with endovascular aneurysm repair (EVAR) of abdominal aortic aneurysm.

Materials and Methods

Ninety-three patients (mean age ± standard deviation, 72 years ± 8; range, 56-88 years) with EVAR and type II endoleak were included in a single-institution retrospective study conducted between March 1, 2005, and December 31, 2018. ENV_AP, ENV_DP, change of volume (ENV_DP-AP), and percentage of ENV_AP and ENV_DP in aneurysm sac volume (ASV) (ENV_AP/ASV%, ENV_DP/ASV%, respectively) were measured on first postoperative CTA images. The mean follow-up was 31.6 months ± 26.6 (range, 6-163.8 months). Patients were divided into two groups (group A, spontaneous resolution of endoleak without intervention [n = 29] and group B, persistent endoleak at follow-up CTA [n = 64]) and compared by using the Mann-Whitney U, Wilcoxon signed rank, and Pearson χ² tests. Receiver operating characteristic (ROC) analysis was used to compare accuracies of parameters at first postoperative CTA.

Results

The accuracy of ENV_DP (area under the ROC curve [AUC], 0.78) was superior to the accuracy of ENV_DP/ASV% (AUC, 0.76), ENV_DP-AP (AUC, 0.74), ENV_AP (AUC, 0.71), and ENV_AP/ASV% (AUC, 0.69) in indicating persistent endoleak. In group B, 46 patients (72%) showed ASV enlargement and 44 patients (69%) underwent endoleak embolization. ENV_AP (1.7 cm³ ± 2.9 vs 3.4 cm³ ± 4.2; P = .001), ENV_DP (2.9 cm³ ± 3.8 vs 8.0 cm³ ± 9.6; P < .001), ENV_DP-AP (1.1 cm³ ± 1.8 vs 4.5 cm³ ± 7.8; P < .001), ENV_AP/ASV% (0.9% ± 1.5 vs 1.7% ± 2.2; P = .003), and ENV_DP/ASV% (1.6% ± 2.2 vs 3.7% ± 3.6; P < .001) were smaller in group A than in group B.

Conclusion

ENV_DP of the first postoperative CTA is an accurate predictor of persistent endoleak compared with ENV_AP, and persistent endoleak is associated with aneurysm sac enlargement, in which earlier intervention is recommended.© RSNA, 2021.

CT texture analysis predicts abdominal aortic aneurysm post-endovascular aortic aneurysm repair progression

The aim of this study is to investigate the role of early postoperative CT texture analysis in aneurysm progression. Ninety-nine patients who had undergone post-endovascular aneurysm repair (EVAR) infra-renal abdominal aortic aneurysm CT serial scans were enrolled from July 2014 to December 2019. The clinical and traditional imaging features were obtained. Aneurysm texture analysis was performed using three methods—the grey-level co-occurrence matrix (GLCM), the grey-level run length matrix (GLRLM), and the grey-level difference method (GLDM). A multilayer perceptron neural network was applied as a classifier, and receiver operating characteristic (ROC) curve analysis and area under the curve (AUC) analysis were employed to illustrate the classification performance. No difference was found in the morphological and clinical features between the expansion (+) and (−) groups. GLCM yielded the best performance with an accuracy of 85.17% and an AUC of 0.90, followed by GLRLM with an accuracy of 87.23% and an AUC of 0.8615, and GLDM with an accuracy of 86.09% and an AUC of 0.8313. All three texture analyses showed superior predictive ability over clinical risk factors (accuracy: 69.41%; AUC: 0.6649), conventional imaging features (accuracy: 69.02%; AUC: 0.6747), and combined (accuracy: 75.29%; AUC: 0.7249). Early post-EVAR arterial phase-derived aneurysm texture analysis is a better predictor of later aneurysm expansion than clinical factors and traditional imaging evaluation combined.

The association between perioperative embolization of hypogastric arteries and type II endoleaks after endovascular aortic aneurysm repair

OBJECTIVE

Type II endoleaks (T2ELs) are the most common type of endoleak after endovascular aneurysm repair (EVAR). The iliolumbar artery arising from the hypogastric artery is often a major source of T2ELs, and transarterial embolization of the iliolumbar artery through the hypogastric artery is sometimes performed to interrupt sac expansion during follow-up. Considering the equivocal results of an association between hypogastric embolization and T2ELs in previous studies, this topic has re-emerged after the advent of iliac branch devices. This study reviewed our series to clarify whether hypogastric embolization is associated with T2ELs at 12 months after EVAR.

METHODS

Patients who underwent elective EVAR between June 2007 and May 2017 at our institution were retrospectively reviewed. Patients with postoperative computed tomography angiography (CTA) at 12 months were included. Patients in whom CTA revealed type I or type III endoleaks during follow-up, who required reinterventions before 12 months, and who had solitary iliac aneurysms were excluded. The primary outcome was the incidence of T2ELs at 12 months after EVAR. The associations of patients' characteristics, anatomic factors, hypogastric embolization, and type of endograft with the primary outcome were analyzed.

RESULTS

In total, 375 patients were enrolled. During the median follow-up of 59.5 months (interquartile range, 19-126 months), 40 patients died, and 50 reinterventions were performed. In 108 patients (28.8%), either hypogastric artery was embolized to extend distal landings to the external iliac artery. Bilateral and unilateral embolization was performed in nine and 99 patients, respectively. In total, 153 patients (40.8%) had T2ELs found by CTA at 12 months. In the univariate analysis, the status of hypogastric artery occlusion or embolization was not significantly different between patients with and without T2ELs. However, there were not enough patients to detect a 10% difference in T2ELs with >80% statistical power. In the multivariate analysis, significant associations with T2EL were observed for female sex (P = .049), patent inferior mesenteric artery (P = .006), and presence of five or more patent lumbar arteries (P < .001) but not for hypogastric embolization. In addition, compared with the Zenith (Cook Medical, Bloomington, Ind) endograft, the Excluder (W. L. Gore & Associates, Flagstaff, Ariz) endograft was significantly related to T2EL (P = .001).

CONCLUSIONS

No significant association between hypogastric embolization and T2EL was demonstrated in this retrospective study, which lacked adequate statistical power.

Type 2 Endoleak Incidence and Fate After Endovascular Aneurysms Repair in a Multicentric Series: Different Results with Different Devices?

BACKGROUND

The aim of this work is describing incidence and fate of type 2 endoleaks (T2ELs) in a multicentric cohort of patients treated by endovascular aneurysms repair using the Ovation device (Endologix) and comparing them with a group treated using the Excluder (W. L. Gore & Associates).

METHODS

This is a retrospective study conducted on 261 patients treated using the Ovation device and 203 using the Excluder. Outcomes were intraprocedural, 30-day, 12-month, and mean time follow-up T2EL incidence and related reinterventions. Patent inferior mesenteric artery (IMA), ≥3 lumbar arteries (LAs), intrasac thrombus volume, the mean diameter of common and external iliac arteries, external iliac artery stenosis (>70%), diameter ≤5 mm, iliac tortuosity ratio ≤0.5, thrombosis, and calcification were noted and considered as potentially influencing outcomes.

RESULTS

Patients of the Ovation group presented significantly more thrombosed, calcified, and tortuous iliac vessels than those in the Excluder group. No significant differences were noted in sac thrombosis, IMA, and LA patency. At completion angiography, T2EL was evident in 57 Ovation and 46 Excluder patients (P = 0.832). At 1 month, it was evident in 33 Ovation group and 28 Excluder group patients (P = 0.726). At 12-month and mean time (30.14 months) follow-up, no differences were evident between the 2 groups (P = 0.940 and 0.951, respectively). The log-rank test showed that the rate of T2EL-related reintervention was not different between the 2 groups (P = 0.46). Regarding anatomical characteristics, a statistically significant difference was not observed between patients presenting or not with T2EL (P > 0.05).

CONCLUSIONS

Data showed no significant differences in terms of T2EL incidence between the 2 study groups. None of preoperative anatomical features were found to be significantly associated with the appearance of T2EL.

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.

Prevalence and risk factors of type II endoleaks after endovascular aneurysm repair: A meta-analysis

OBJECTIVES

This systematic review and meta-analysis aims to determine the current evidence on risk factors for type II endoleaks after endovascular aneurysm repair (EVAR).

MATERIALS AND METHODS

A systematic literature search was carried out for studies that evaluated the association of demographic, co-morbidity, and other patient-determined factors with the onset of type II endoleaks. Pooled prevalence of type II endoleaks after EVAR was updated.

RESULTS

Among the 504 studies screened, 45 studies with a total of 36,588 participants were included in this review. The pooled prevalence of type II endoleaks after EVAR was 22% [95% confidence interval (CI), 19%-25%]. The main factors consistently associated with type II endoleaks included age [pooled odds ratio (OR), 0.37; 95% CI, 0.31-0.43; P<0.001], smoking (pooled OR, 0.71; 95% CI, 0.55-0.92; P<0.001), patent inferior mesenteric artery (pooled OR, 1.98; 95% CI, 1.06-3.71; P = 0.012), maximum aneurysm diameter (pooled OR, 0.23; 95% CI, 0.17-0.30; P<0.001), and number of patent lumbar arteries (pooled OR, 3.07; 95% CI, 2.81-3.33; P<0.001). Sex, diabetes, hypertension, anticoagulants, antiplatelet, hyperlipidemia, chronic renal insufficiency, types of graft material, and chronic obstructive pulmonary diseases (COPD) did not show any association with the onset of type II endoleaks.

CONCLUSIONS

Clinicians can use the identified risk factors to detect and manage patients at risk of developing type II endoleaks after EVAR. However, further studies are needed to analyze a number of potential risk factors.

Outcomes of type II endoleaks after endovascular abdominal aortic aneurysm (AAA) repair: a single-center, retrospective study

PURPOSE

This study aims to determine incidence and outcomes of type II endoleaks (T2E) after endovascular abdominal aortic aneurysm repair (EVAR).

METHODS

A retrospective review of procedural angiograms, computed tomography angiography, and medical records of 202 patients who underwent EVAR with the Gore Excluder stent graft was performed to determine presence and outcomes of T2E.

RESULTS

Median follow-up time for 163 patients meeting inclusion criteria [136 males (83%)] was 24.7 months (range=0.5-85.2 months). T2E occurred in 66/163 patients (40.5%). Aneurysm sac size was unchanged in 32/66 patients (48.5%), decreased in 22/66 (33.3%), and increased in 12/66 (18.2%). No aneurysm ruptures, conversion to open repair, or aneurysm-related deaths occurred.

CONCLUSION

T2E are a common occurrence after EVAR, often with benign outcome. However, routine surveillance should be performed, particularly in patients with persistent endoleak or sac growth.

Risk factors and consequences of persistent type II endoleaks

OBJECTIVE

Type II endoleaks are common after endovascular aneurysm repair (EVAR), but their clinical significance remains undefined and their management controversial. We determined risk factors for type II endoleaks and associations with adverse outcomes.

METHODS

We identified all EVAR patients in the Vascular Study Group of New England abdominal aortic aneurysm database. Patients were subdivided into two groups: (1) those with no endoleak or transient type II endoleak and (2) persistent type II endoleak or new type II endoleak (no endoleak at completion of case). Patients with other endoleak types and follow-up shorter than 6 months were excluded. Multivariable analysis was used to evaluate predictors of persistent or new type II endoleaks. Kaplan-Meier and Cox regression analysis were used to evaluate predictors of reintervention and survival.

RESULTS

Two thousand three hundred sixty-seven EVAR patients had information on endoleaks: 1977 (84%) were in group 1, of which 79% had no endoleaks at all, and 21% had transient endoleaks that resolved at follow-up. The other 390 (16%) were in group 2, of which 31% had a persistent leak, and 69% had a new leak at follow-up that was not seen at the time of surgery. Group 2 was older (mean age, 75 vs 73 years; P < .001) and less likely to have chronic obstructive pulmonary disease (COPD; 24% vs 34%; P < .001) or elevated creatinine levels (2.6% vs 5.3%; P = .027). Coil embolization of one or both hypogastric arteries was associated with a higher rate of persistent type II endoleaks (12 vs 8%; P = .024), as was distal graft extension (12% vs 8%; P = .008). In multivariable analysis, COPD (odds ratio [OR], 0.7; 95% confidence interval [CI], 0.5-0.9; P = .017) was protective against persistent type II endoleak, while hypogastric artery coil embolization (OR, 1.5; 95% CI, 1.0-2.2; P = .044), distal graft extension (OR, 1.6; 95% CI, 1.1-2.3; P = .025), and age ≥ 80 (OR, 2.7; 95% CI, 1.4-5.3; P = .004) were predictive. Graft type was also associated with endoleak development. Persistent type II endoleaks were predictive of postdischarge reintervention (OR, 15.3; 95% CI, 9.7-24.3; P < .001); however, they were not predictive of long-term survival (OR, 1.1; 95% CI, 0.9-1.6; P = .477).

CONCLUSIONS

Persistent type II endoleak is associated with hypogastric artery coil embolization, distal graft extension, older age, the absence of COPD, and graft type, but not with aneurysm size. Persistent type II endoleaks are associated with an increased risk of reinterventions, but not rupture or survival. This reinforces the need for continued surveillance of patients with persistent type II endoleaks and the importance of follow-up to detect new type II endoleaks over time.

Management of acute limb ischemia after glue embolization of endoleak following endovascular abdominal aortic aneurysm repair

We describe the case of a 73-year-old woman who developed a type II endoleak and subsequent aneurysm sac expansion following endovascular abdominal aortic aneurysm repair. The endoleak was treated with a translumbar direct sac puncture and injection with n-butyl-2-cyanoacrylate. During the injection procedure, glue embolized distally, lodging into the right popliteal, proximal anterior tibial, and tibioperoneal arteries, causing acute limb ischemia that led to an emergency embolectomy. The patient recovered well, and the postoperative course was unremarkable. Acute limb ischemia secondary to glue embolization during endoleak management is rare, with potentially catastrophic complications that require urgent operative repair.

Volumetric quantification of type II endoleaks: an indicator for aneurysm sac growth following endovascular abdominal aortic aneurysm repair

PURPOSE

To test the hypothesis that type II endoleak cavity volume (ECV) and endoleak cavity diameter (ECD) measurements are accurate indicators of aneurysm sac volume (ASV) enlargement in patients who undergo endovascular aneurysm repair (EVAR) in the abdominal aorta.

MATERIALS AND METHODS

The institutional review board approved and waived the need to obtain patient consent for this HIPAA-compliant retrospective study. In 72 patients who underwent EVAR, 160 computed tomographic (CT) angiography studies revealed type II endoleaks. Corresponding to these 160 CT angiography studies, 113 CT follow-up studies (in 52 patients) were available and were included in the analysis. ECV measurements were obtained by two observers in consensus by using arterial enhanced phase (ECVAEP) and 70-second delayed enhanced phase (ECVDEP) CT images. The ECVDEP was also normalized as the ECV/ASV ratio. Maximum (ECDM) and transverse (ECDT) ECDs were determined from delayed enhanced phase images. The outcome was determined as interval increase (>2%) in ASV versus stable or decreasing (≤2%) ASV. Receiver operating characteristic (ROC) analysis was used to compare the accuracy of type II ECV and ECD measurements in indicating interval increase in ASV.

RESULTS

In 56 (49.5%) of 113 CT studies in type II endoleaks, there was an interval increase in ASV. The accuracies of ECVDEP (area under the ROC curve [AUC], 0.85) and normalized ECVDEP (AUC, 0.86) were superior to the accuracies of ECDM (AUC, 0.73), ECDT (AUC, 0.73), and ECVAEP (AUC, 0.66). At ROC curve analysis, the sensitivity, specificity, and positive and negative predictive values for type II endoleak cavities with an ECVDEP of less than 0.5 mL for showing no future sac volume enlargement were 33% (19 of 57), 100% (56 of 56), 100% (19 of 19), and 60% (56 of 94), respectively.

CONCLUSION

With use of the delayed enhanced phase of CT angiography, ECV measurement is an accurate indicator of aneurysm sac enlargement.

Type II endoleak after endovascular aneurysm repair

BACKGROUND

The aim was to assess the risk of rupture, and determine the benefits of intervention for the treatment of type II endoleak after endovascular abdominal aortic aneurysm repair (EVAR).

METHODS

This systematic review was done according to PRISMA guidelines. Outcome data included incidence, spontaneous resolution, sac expansion, interventions, clinical success, and complications including conversion to open repair, and rupture.

RESULTS

Thirty-two non-randomized retrospective studies were included, totalling 21 744 patients who underwent EVAR. There were 1515 type II endoleaks and 393 interventions. Type II endoleak was seen in 10·2 per cent of patients after EVAR; 35·4 per cent resolved spontaneously. Fourteen patients (0·9 per cent) with isolated type II endoleak had ruptured abdominal aortic aneurysm; six of these did not have known aneurysm sac expansion. Of 393 interventions for type II endoleak, 28·5 per cent were unsuccessful. Translumbar embolization had a higher clinical success rate than transarterial embolization (81 versus 62·5 per cent respectively; P = 0·024) and fewer recurrent endoleaks were reported (19 versus 35·8 per cent; P = 0·036). Transarterial embolization also had a higher rate of complications (9·2 per cent versus none; P = 0·043).

CONCLUSION

Aortic aneurysm rupture after EVAR secondary to an isolated type II endoleak is rare (less than 1 per cent), but over a third occur in the absence of sac expansion. Translumbar embolization had a higher success rate with a lower risk of complications.

Embolization of a Recurrent Type 2 Endoleak Using the Liquid Embolic n-Butyl Cyanoacrylate

Endovascular aneurysm repair (EVAR) has become an accepted alternative to open aortic aneurysm repair. Endoleaks are one of the most common complications of EVAR and can result in aneurysm enlargement and rupture. When embolization of type 2 endoleaks is needed, a transarterial or translumbar approach may be used. Metal coils are often utilized, but liquid agents have also been used for embolization. This case report involves endoleak embolization using metallic coils along with the liquid embolic agent n-butyl cyanoacrylate (n-BCA).

Endoscopic type 2 endoleak repair following endovascular aortic aneurysm repair: acute results and follow-up experience

The purpose of this study was to evaluate immediate and long-term results of endoscopic type 2 endoleak repair (EER) following endovascular abdominal aortic aneurysm repair. The basic methods include a retrospective review of electronic and paper medical records of patients admitted or referred to our institution for EER. Between July 1999 and October 2007, eight consecutive patients underwent EER. Mean operative time was 190 (104–355) min. One patient died preoperatively, due to profuse venous bleeding . One procedure was redone due to a missed pair of lumbar arteries. Mean hospital stay was five days (2–10). During mean follow-up, 50 months (29–91), one patient required additional coil embolization for a persistent type 2 endoleak. Four patients were diagnosed with a type 1 and one with a type 3 endoleak; three of these patients required an additional procedure. In conclusion, in this small series EER proved not to be beneficial.

Ischemic skin ulceration complicating glue embolization of type II endoleak after endovascular aneurysm repair

The optimal treatment for type II endoleaks remains unclear. The present report describes a case of ischemic skin ulceration after glue embolization of a type II endoleak with challenging access in a multiply comorbid 82-year-old woman with an expanding aneurysm sac 3 years after endovascular aneurysm repair. Embolization was performed from a proximal position with an n-butyl cyanoacrylate/Ethiodol mixture to allow flow into the endoleak because direct sac puncture was hazardous. One week after intervention, an eschar, which progressed to superficial necrosis as a result of partial nontarget delivery of sclerosant, developed over the left iliac crest. The eschar was self-limiting, with complete resolution by 6 months.

Endovascular abdominal aortic aneurysm repair: nonenhanced volumetric CT for follow-up

PURPOSE

To evaluate the clinical usefulness of volumetric analysis at nonenhanced computed tomography (CT) as the sole method with which to follow up endovascular abdominal aortic aneurysm repair (EVAR) and to identify endoleaks causing more than 2% volumetric increase from the previous volume determination.

MATERIALS AND METHODS

The study had institutional review board approval. Images were reviewed retrospectively in a HIPAA-compliant manner for 230 CT studies in 70 patients (11 women, 59 men; mean age, 74 years) who underwent EVAR. The scannning protocol consisted of three steps: (a) contrast material-enhanced CT angiography before endovascular stent placement, (b) contrast-enhanced CT angiography 0-3 months after repair to depict immediate complications, and (c) nonenhanced CT at 3, 6, and 12 months after repair. At each follow-up visit, immediate aortic volume analysis was performed. If the interval volumetric change was 2% or less, no further imaging was performed. If the volume increased by more than 2% on the nonenhanced CT image, contrast-enhanced CT angiography was performed immediately to identify the suspected endoleak. Confidence intervals (CIs) were obtained by using bootstrapping to account for repeated measurements in the same patients.

RESULTS

Mean volume decrease was -3.2% (95% CI: -4.7%, -1.9%) in intervals without occurrence of a clinically relevant endoleak (n = 183). Types I and III high-pressure endoleaks (n = 10) showed a 10.0% (95% CI: 5.0%, 18.2%) interval volumetric increase. Type II low-pressure endoleaks (n = 37) showed a 5.4% (95% CI: 4.6%, 6.2%) interval volumetric increase. Endoleaks associated with minimal aortic volume increase of less than 2% did not require any intervention. This protocol reduced radiation exposure by approximately 57%-82% in an average-sized patient.

CONCLUSION

Serial volumetric analysis of aortic aneurysm with nonenhanced CT serves as an adequate screening test for endoleak, causing volumetric increase of more than 2% from the volume seen at the previous examination.

Large iliac arteries: a high-risk group for endovascular aortic aneurysm repair

PURPOSE

To examine if the presence of large iliac arteries is a potential risk factor for the development of a type Ib endoleak (iliac sealing zone) or need for iliac artery-related secondary intervention in patients undergoing endovascular abdominal aortic aneurysm repair.

METHODS

The medical notes and all preoperative and postoperative plain abdominal radiographs and computer tomographic scans were reviewed for a consecutive series of 100 patients (89 men; mean age 75 years, range 56-91) with large iliac arteries (mean 19.7 mm, range 16-22) who had Zenith endovascular stent-grafts inserted for management of aortoiliac aneurysmal disease from January 1999 until September 2002. Endpoints were all-cause mortality, aneurysm-related death, endoleak, secondary intervention, secondary interventions, and stent-graft migration.

RESULTS

Mean follow-up was 30.1+/-8.3 months; at the last follow-up, 30% of patients were dead, 3% were aneurysm-related. Seven (7%) patients developed a type Ib endoleak, with the remainder being type II (29%), type Ia (2%), type III (1%), and type V (endotension, 1%). Eight (27.5%) type II endoleaks persisted, with the remainder closing spontaneously with sac shrinkage. The iliac artery-related secondary intervention rate was 10%, and the overall secondary intervention rate was 16%.

CONCLUSION

Iliac arteries between 16 and 22 mm in diameter may be treated with a cuff to the iliac limb with an expectation of 90% efficacy. Surveillance is required, with a high index of suspicion for type 1b endoleaks. Early secondary iliac intervention with extension to the external iliac artery is recommended if there is an increase in sac size after 6 months.

An 8-year experience with type II endoleaks: Natural history suggests selective intervention is a safe approach

OBJECTIVE

The treatment of type II endoleaks remains controversial because little is known about their long-term natural history and impact on changes in aneurysm morphology. This study reviews type II endoleaks occurring in patients after endovascular abdominal aortic aneurysm repair (EVAR) at a single-institution over an 8-year period.

METHODS

All patients undergoing EVAR who had type II endoleaks documented on follow-up imaging studies at our institution between January 1997 and March 2005 were reviewed. Data regarding patient demographics in addition to aneurysm size, device type, operative complications, and secondary interventions were reviewed. Outcomes evaluated included the rate of spontaneous sealing, freedom from secondary intervention, and aneurysm enlargement, rupture, or conversion.

RESULTS

Type II endoleaks were present in 154 of 965 patients (16.0%) undergoing EVAR. Mean follow-up time was 22.0 months (range, 1 to 72 months). Fifty-five patients (35.7%) with type II endoleaks sealed spontaneously in a mean time of 14.5 months. According to Kaplan-Meier analysis, approximately 75% of type II endoleaks sealed spontaneously within a 5-year period. Nineteen patients (12.3%) with type II endoleaks were treated at a mean time of 19.9 months at the operating surgeon's discretion, including 13 with sac enlargement >5 mm. Kaplan-Meier analysis estimated that approximately 65% of the patients remained free of intervention after a period of 4 years. Thirteen patients (8.4%) experienced aneurysm sac enlargement >5 mm. Kaplan-Meier analysis estimated that approximately 80% of patients with type II endoleaks remained free of sac enlargement >5 mm over a 4-year period. No patients with type II endoleaks experienced rupture or required conversion to open repair during their follow-up. Cox regression analysis showed that cancer, coronary artery disease, and chronic obstructive pulmonary disease were associated with earlier spontaneous closure of the type II endoleaks (P < .05).

CONCLUSIONS

We observed that type II endoleaks have a relatively benign course, and in the absence of sac expansion, can be followed for a prolonged course of time without the need for intervention. The rate of spontaneous seal continues to increase with time and, therefore, close follow-up of patients with type II endoleaks who show no signs of aneurysm expansion is a safe approach. For patients in whom the exact etiology of their endoleak is in question, dynamic imaging should be used to exclude the presence of a type I endoleak.

Computed tomography versus magnetic resonance imaging of endoleaks after EVAR

AIM

The aim of study was to compare the sensitivity of MRI and CTA for endoleak detection and classification after EVAR.

PATIENTS & METHODS

Twenty-eight patients, between 2 days and 65 months after EVAR, were evaluated with both CT and MRI. Twenty-five patients had an Ancure graft and the other three had an Excluder. The MRI protocol for endoleak evaluation included: a T1-weighted spin echo, a high-resolution 3D CE-MRA, and a post-contrast T1-weighted spin echo. In total 40 ml Gadolinium was administered. The CT protocol consisted of a blank survey followed by a spiral CT angiography (CTA) using 140 ml of Ultravist. An experienced, blinded observer evaluated all CTs and MRIs.

RESULTS

Using MRI and MRA techniques significantly more endoleaks (23/35) were detected than with CTA (11/35) (p=0.01, Chi-Square). CT could not determine the type of endoleak in 3 of the 11 endoleaks detected and was uncertain in one. MRI was uncertain about the type in 14 of the 23 endoleaks detected. All endoleaks visible on CT were visible by MRI as well.

CONCLUSIONS

MRI techniques are more sensitive for the detection of endoleak after endovascular AAA repair than CT.

Aneurysm Sac Thrombus Load Predicts Type II Endoleaks after Endovascular Aneurysm Repair

Type II endoleaks are associated with the absence of aneurysm shrinkage after endovascular abdominal aortic aneurysm repair (EVAR). This study aims at determining the predictability of this complication, whose potential risk factors have been the subject of conflicting reports. Preoperative computed tomography (CT) scans of 178 patients who underwent EVAR for true infrarenal abdominal aortic aneurysms between January 20, and April 17, 2003, with a minimum follow-up of 30 days, were reviewed. The following information was retrieved: maximum aneurysm diameter, aneurysm thrombus load (maximum thickness, percentage of sac circumference wall coverage, percentage of maximum sac area occupancy); number, diameter, and nature (lumbar, inferior mesenteric, accessory renal, middle sacral) of patent aortic side-branch arteries; thrombus thickness at each aortic branch ostium, and aneurysm diameter at that level. Postoperative CT and duplex scans supplemented with angiography in selected cases were reviewed for the presence of a type II endoleak observable beyond the 30th postoperative day. Logistic regression was used to assess the association of each variable with this outcome. There were 38 (21.3%) patients with type II endoleaks after the 30th postoperative day. The median follow-up was 12 months (range 1-65 months). By univariate analysis, the following variables significantly decreased the risk of a type II endoleak: thrombus maximum thickness [odds ratio (OR) 0.77 for a 5 mm increase, p = 0.009], mean thrombus thickness at aortic side-branches ostia (OR 0.65 for a 1 mm increase, p = 0.0006), thrombus-occupied percentage of maximum aneurysm area (OR 0.72 for a 10% increase, p < 0.0001), percentage of thrombus-lined aneurysm wall (OR 0.53 for a 25% increase, p < 0.0001). The presence of a patent inferior mesenteric artery (OR 6.84, p < 0.01) and the number of patent aortic side-branches (OR 1.37 for each additional vessel, p = 0.002) significantly increased the risk of detecting a late type II endoleak. Aneurysm and aortic side-branch diameters did not have any impact. In a multiple logistic regression model (whole model p < 0.0001), the thrombus-occupied percentage of maximum aneurysm area (OR 0.74 for a 10% increase, p < 0.0005) and the number of patent aortic side-branches (OR 1.31 for each additional vessel, p = 0.009) remained independent predictors of type II endoleaks. The simple measure of the proportion of maximum aneurysm area occupied by thrombus may be a useful way to identify patients at high risk of a persistent type II endoleak. Patients with low preoperative sac thrombus load should be followed with a high degree of suspicion for this complication.

Does Chronic Oral Anticoagulation With Warfarin Affect Durability of Endovascular Aortic Aneurysm Exclusion in a Midterm Follow-up?

PURPOSE

To evaluate the effect of oral anticoagulation on durability of endovascular aortic aneurysm repair (EVAR).

METHODS

Retrospective review was conducted of 182 consecutive EVAR patients (169 men; mean age 75.3 years, range 53-89) between 1999 and 2003. Patients on warfarin anticoagulation (WA, n=21; International Normalized Ratio of 2 to 3) were compared against a control group (CG) with no postoperative anticoagulation (n=161). Death, aneurysm rupture, and reintervention were considered primary endpoints; endoleaks, endograft migration, and aneurysm remodeling were secondary endpoints.

RESULTS

Mean follow-up was 16.3+/-12.6 months. One-year mortality was 6.6% (9.5% WA versus 6.2% CG); overall mortality was 14.3% (p=0.414). No aneurysm rupture occurred. At 1, 2, and 3 years, respectively, cumulative reinterventions (20%/20%/20% WA versus 12%/15%/20% CG; p=0.633) and endoleak rates (25%/25%/25% WA versus 17%/22%/34% CG; p=0.649) were comparable. In both groups, most completion endoleaks resolved (42.9% WA versus 74.4% CG; p=0.474), but few de novo endoleaks did (0% WA versus 12.8% CG; p=0.538). Anticoagulation did not affect mean time to aneurysm sac shrinkage (1.3+/-0.3 WA versus 1.4+/-0.1 years CG; p=0.769).

CONCLUSIONS

After EVAR, anticoagulation appears safe and does not significantly alter mortality, risk for rupture, or the incidence of reintervention. Early endoleaks appear more common in anticoagulated patients, but anticoagulation does not preclude spontaneous endoleak resolution nor does it increase late endoleak rates. Irrespective of the anticoagulation status, early but not late endoleaks usually sealed spontaneously. Observing type II endoleaks appears safe in the absence of aneurysm enlargement.

Type II endoleak after endovascular abdominal aortic aneurysm repair: a conservative approach with selective intervention is safe and cost-effective

OBJECTIVES

The conservative versus therapeutic approach to type II endoleak after endovascular repair of abdominal aortic aneurysm (EVAR) has been controversial. The purpose of this study was to evaluate the safety and cost-effectiveness of the conservative approach of embolizing type II endoleak only when persistent for more than 6 months and associated with aneurysm sac growth of 5 mm or more.

METHODS

Data for 486 consecutive patients who underwent EVAR were analyzed for incidence and outcome of type II endoleaks. Spiral computed tomography (CT) scans were reviewed, and patient outcome was evaluated at either office visit or telephone contact. Patients with new or late-appearing type II endoleak were evaluated with spiral CT at 6-month intervals to evaluate both persistence of the endoleak and size of the aneurysm sac. Persistent (>or=6 months) type II endoleak and aneurysm sac growth of 5 mm or greater were treated with either translumbar glue or coil embolization of the lumbar source, or transarterial coil embolization of the inferior mesenteric artery.

RESULTS

Type II endoleaks were detected in 90 (18.5%) patients. With a mean follow-up of 21.7 +/- 16 months, only 35 (7.2%) patients had type II endoleak that persisted for 6 months or longer. Aneurysm sac enlargement was noted in 5 patients, representing 1% of the total series. All 5 patients underwent successful translumbar sac embolization (n = 4) or transarterial inferior mesenteric artery embolization (n = 4) at a mean follow-up of 18.2 +/- 8.0 months, with no recurrence or aneurysm sac growth. No patient with treated or untreated type II endoleak has had rupture of the aneurysm. The mean global cost for treatment of persistent type II endoleak associated with aneurysm sac growth was US dollars 6695.50 (hospital cost plus physician reimbursement). Treatment in the 30 patients with persistent type II endoleak but no aneurysm sac growth would have represented an additional cost of US dollars 200000 or more. The presence or absence of a type II endoleak did not affect survival (78% vs 73%) at 48 months.

CONCLUSIONS

Selective intervention to treat type II endoleak that persists for 6 months and is associated with aneurysm enlargement seems to be both safe and cost-effective. Longer follow-up will determine whether this conservative approach to management of type II endoleak is the standard of care.

Late-onset Type II Endoleaks and the Incidence of Secondary Intervention

Type II endoleaks are a recognized complication of endoluminal treatment of abdominal aortic aneurysms. In order to better understand the natural history of type II endoleaks and their influence on secondary procedures, we examined our experience with patients who developed isolated type II endoleaks 6 months or more after their original procedure. We conducted a retrospective review of patients who underwent endoluminal repair of infrarenal abdominal aortic aneurysms with bifurcated endoluminal devices at a single institution from June 1996 to June 2000. Endoleak surveillance was performed on all patients by using a defined CT angiogram protocol. Patients with definitive and isolated type II endoleaks on CT angiogram were identified. Patients with indeterminate endoleaks or a combination of different types of endoleaks were excluded. Data were analyzed on the basis of early (<6 months) or late occurrence of isolated type II endoleak. Fifty patients were identified with isolated type II endoleaks. Of these patients, 20 (40%) had endoleaks discovered before the 6-month follow-up interval whereas the majority (60%) had new type II leaks discovered at least 6 months after their initial procedure. The timing of endoleak occurrence did not significantly influence the rate of spontaneous endoleak resolution between the early- (<6 months) and late-onset (>6 months) groups, which was nearly identical (40% vs. 43%). Ten patients in the early group and seven of the late-onset group required secondary intervention for treatment of type II endoleak (50% vs. 23%; NS). Three patients in the early group underwent surgical conversion (vs. 0 patients in the late-onset group). The mortality rate was not significantly different between groups (15% vs. 7%). Most isolated type II endoleaks in this patient population occurred 6 months or more after initial endoluminal repair of infrarenal abdominal aortic aneurysm. Timing of type II endoleak occurrence did not significantly affect the rates of spontaneous resolution or mortality. Although differences were observed in the number of patients receiving secondary interventions, these findings did not reach statistical difference. All patients who required surgical conversion had early type II endoleaks. There were no observed ruptures in patients with increased aneurysm size treated with secondary intervention or those with stable aneurysm volumes who were followed without intervention. The continued development of type II endoleaks beyond the perioperative period supports the need for continued endoleak surveillance.

Initial successful management of type I endoleak after endovascular aortic aneurysm repair with n-butyl cyanoacrylate adhesive

OBJECTIVE

Transcatheter embolization with coils and other agents has been described as a treatment method for type II endoleak after endovascular aortic aneurysm repair (EVAR). Type I endoleak has not been treated commonly with such therapies, although most investigators believe they warrant definitive intervention. The liquid adhesive n-butyl 2-cyanoacrylate (n-BCA) is often used to treat congenital arteriovenous malformations. The objective of this study is to report our initial experience in treating type I endoleak with n-BCA and with a variety of other interventions.

METHODS

A retrospective review was performed of 270 patients who underwent EVAR at our institution between January 1994 and December 2002. Of these, 24 patients had type I endoleak (8.9%), diagnosed either intraoperatively (n = 13, 52%) or during follow-up (n = 12, 48%). Among these 24 patients, 17 had proximal leaks and the remaining 8 patients had distal leaks. These cases form the focus of this study.

RESULTS

Twenty-two leaks required endovascular intervention, with the following success rate: n-BCA, 12 of 13 cases (92.3%); extender cuffs, 4 of 5 cases (80%); coils with or without thrombin, 3 of 4 cases (75%). In one patient with persistent endoleak despite attempted endovascular intervention the device ultimately was surgically explanted, and the patient did well. Of six patients with endoleak initially managed expectantly, two eventually underwent attempts at definitive intervention, both with n-BCA. Three sealed spontaneously before definitive intervention could be performed; and in one 97-year-old patient who refused intervention, the aneurysm subsequently ruptured and the patient died. In total, 13 patients with type I endoleak underwent n-BCA transcatheter embolotherapy. No serious complications were directly related to this therapy. Colon ischemia developed in one patient, and was believed to be a result of thromboembolism during wire and catheter manipulation rather than n-BCA treatment. Twelve of these 13 leaks remain sealed at mean follow-up of 5.9 months (range, 0-19 months).

CONCLUSION

Our initial use of n-BCA occlusion suggests that it may be an effective and safe method of treatment of type I endoleak after EVAR. In particular, n-BCA embolotherapy may be especially useful in treating type I endoleak not amenable to placement of extender cuffs. Larger case series and longer follow-up are needed before this treatment is more broadly recommended. Type I endoleak after EVAR can be treated successfully with a variety of endovascular methods, and surgical explantation is rarely required.

Controversies in the management of type II "branch" endoleaks following endovascular abdominal aortic aneurysm repair

Successful endovascular aortic aneurysm repair (EVAR) is often defined as complete exclusion of blood flow within the aneurysm sac. Perigraft flow, also known as endoleak, is the most common complication following EVAR. Attachment site related endoleaks (type I) are generally considered to warrant some form of intervention due to the belief that they represent a risk for future rupture. Management of type II endoleaks, also known as branch or collateral endoleaks, is more controversial. Some advocate a policy of watchful-waiting whereas others treat all type II endoleaks as soon as they are discovered. The following review explores the controversies pertaining to the management, diagnosis and surveillance imaging, and treatment of type II endoleaks.