Effectiveness of Intra-operative Contrast-Enhanced Ultrasound Assessment to Optimize Type II Endoleak Embolization

PURPOSE

To analyze the effectiveness of type II endoleaks (T2E) embolization using intra-operative contrast-enhanced ultrasound (CEUS).

METHODS

Consecutive patients treated for T2E underwent a standardized protocol with trans-arterial or trans-lumbar access, large volume embolization, onlay fusion, and intra-operative CEUS. Technical success was defined by exclusion of endoleak by CEUS.

RESULTS

Twenty-six patients (mean age 81 ± 11 years old; 89% male) were treated. The mean aneurysm sac enlargement was 11 ± 8 mm from T2E diagnosis. Embolization was performed using Onyx® 18 in all patients with adjunctive coils in 13 patients (50%). After the first embolization, CEUS documented residual T2E in 13 patients (50%). Ten patients (38%) had additional embolization, which successfully eradicated the T2E in seven of them. Technical success was 50% after the first embolization attempt and 77% after additional attempts guided by CEUS (P = 0.080). There was no mortality. Median imaging follow-up was 22 months. Among the 20 patients with no residual T2E on completion CEUS, 16 (80%) had sac stabilization and none required additional interventions for T2E. Of the six patients with residual T2Es on CEUS, three had sac stabilization (50%) and one required additional reintervention for T2E. There was one late aortic rupture at 56 months.

CONCLUSION

One in two patients treated by T2E embolization had residual endoleak on intra-operative CEUS after a first embolization attempt, decreasing to one in four patients after multiple attempts. A negative completion CEUS following embolization was associated with higher rates of sac stabilization and no need for additional T2E embolization.

The Challenge of Endoleaks in Endovascular Aneurysm Repair (EVAR): A Review of Their Types and Management

An abdominal aortic aneurysm (AAA) is a dilatation of the abdominal aorta above 3 cm or 50% greater than the segment above. It is a dangerous condition accounting for a substantial number of deaths per year and increasing at an alarming rate. Various factors come into play in the development of AAAs, which this study has elaborated on, including smoking and old age, demographics, and comorbid conditions. Endovascular aneurysm repair (EVAR) is a newer treatment modality used for AAAs in which an endograft device is placed into the aorta, thereby creating a bypass tract from the aneurysm and generating flow mimicking that of the natural aorta. It is minimally invasive and associated with less postoperative mortality and reduced hospital stay. However, EVAR is also associated with significant postoperative complications, including endoleaks, which were reviewed in depth. Endoleaks are postprocedural leaks into the aneurysm sac that are usually identified immediately after graft placement and indicate treatment failure. They are of five subtypes, categorized according to their mechanism of development. The most common type is type II endoleaks, and the most dangerous is type I endoleaks. Each subtype has multiple management options with varying rates of success. Prompt identification along with appropriate treatment of endoleaks can lead to better postoperative outcomes and improved quality of life for patients.

Outcomes of EVAR Conversion in Octogenarians Treated at a High-Volume Aorta Center

INTRODUCTION

Endovascular aortic aneurysm repair(EVAR) is the dominant treatment strategy for infrarenal abdominal aortic aneurysms(AAA) but is especially preferred among octogenarian(age ≥80-years) patients due to concerns surrounding comorbidity severity and physiological frailty. Correspondingly, EVAR failure resulting in subsequent open conversion(EVAR-c) has been increasingly reported in older patients but there is a paucity of literature focusing on outcomes in this subgroup. The purpose of this analysis was to evaluate our experience with EVAR-c in octogenarians(≥80-years) compared to younger patients(age <80-years).

METHODS

A retrospective review of all non-mycotic EVAR-c procedures(2002-2020) at a single high-volume academic hospital with a dedicated aorta center(https://www.uf-health-aortic-disease-center) was performed. Patients(n=162) were categorized into octogenarian(age ≥80; n=43) and non-octogenarian(age<80; n=119) cohorts and subsequently compared. The primary end-point was 30-day mortality. Secondary end-points included complications, 90-day mortality, and overall survival. Cox regression determined effects of selected covariates on mortality risk. Kaplan-Meier methodology estimated survival.

RESULTS

No difference in pre-admission EVAR re-intervention rates was present(octogenerians-42% vs. non-octogenerians-43%;p=1) although time to first re-intervention was greater in octogenarians(41 vs. non-octogenarians, 15-months;p=.01). Concordantly, time to EVAR-c was significantly longer among octogenarian patients(61 vs. non-octogenarians, 39-months;p<.01). No difference in rupture presentation was evident(14% vs. 10%;p=.6); however, elective EVAR-c occurred less frequently(octogenerians-42% vs. non-octogenerians-59%;p=.07). AAA diameter was significantly larger for elective octogenarian EVAR-c(7.8±1.9cm vs. non-octogenarians, 7.0±1.5cm;p=.02) and type 1a endoleak was the most common indication overall(58%;n=91). Among all presentations, a trend in higher 30-day mortality was evident for octogenarian patients(16% vs. non-octogenarians, 7%;p=.06). Similarly 90-day mortality was greater among octogenarians(26% vs. non-octogenarians, 10%;p=.02). However, incidence of any complication(56% vs. 49%;p=.5), readmission(12% vs. 6%;p=.3), unplanned re-operation(10% vs. 5%;p=.5) and LOS(11 vs. 9 days;p=.3) was not significantly different. Age ≥80 was predictive of short-term mortality after non-elective but not elective cases; however, increasing comorbidity number, non-elective admission and renal/mesenteric revascularization had the strongest association with mortality risk. One- and three-year survival was not different between groups when comparing all patients after the first 90-days postoperatively.

CONCLUSION

Although higher unadjusted peri-operative mortality occurred among octogenarian patients, risk-adjusted elective outcomes were comparable to younger EVAR-c subjects when treated at a high-volume aortic surgery center. This underscores the importance of appropriate patient selection and modulation of operative complexity when feasible to achieve optimal results. Providers caring for octogenarian patients with EVAR failure should consider timely elective referral to high-volume aorta centers to reduce resource utilization and frequency of non-elective presentations.

A systematic review of the current status of interventions for type II endoleak after EVAR for abdominal aortic aneurysms

OBJECTIVE

To study the mid- and long-term outcomes of type II endoleak treatment after EVAR and the technical aspects of different techniques to exclude endoleaks which different embolic agents.

METHODS

A systematic review was performed using the approach recommended by the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines for meta-analyses of interventional studies. The comprehensive search was conducted using the following database: MEDLINE, EMBASE, and the Cochrane Library. Patient characteristic, intervention approaches, embolic agents, and results at mid and long term follow up were studied.

RESULTS

A total of 6 studies corresponding to a total of 141 patients fulfilled the inclusion criteria with a mean age of 73-78.6 years and a mean duration of follow up varying from 25 to 42 months. There were different techniques for embolization used (translumbar, transarterial, and transcaval approach) with various types of embolic agents. In all studies, the indication for embolization of the type II endoleaks was sac enlargement of more than 5 mm. A wide range of technical success rate was reported regardless of the intervention strategy being used (17,6%-100%). The overall technical success rate of all studies was 62%.

CONCLUSION

This systematic review shows that there is a wide variety of techniques to exclude a persistent type II endoleak. Different kinds of embolic agents have be used. Due to a lack of peer reviewed data on longterm follow-up, it was not possible to come to recommendations what treatment would be the best for a durable exclusion of a persistent type II endoleak after an initially successful EVAR. There remains an urgent need for proper executed studies, either randomized or with close observation in relation to longer follow-up.

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.

Surgical treatment patterns and clinical outcomes of patients treated for expanding aneurysm sacs with type II endoleaks after endovascular aneurysm repair

OBJECTIVE

Persistent type II endoleaks (T2ELs) after endovascular aneurysm repair (EVAR) with sac growth have been associated with adverse events, including rupture. Whereas intervention in the presence of aneurysm growth has become an accepted treatment paradigm for T2ELs, the efficacy and clinical success of such interventions remain unclear. Therefore, we examined the treatment patterns and clinical outcomes of patients undergoing T2EL interventions after EVAR.

METHODS

We performed a retrospective review of all patients treated for expanding aneurysm sacs with T2ELs after EVAR at an academic medical center between 2006 and 2017. The primary outcomes assessed were need for repeated intervention; intervention types; and achievement of clinical success, defined as stable aneurysm sac size on computed tomography angiography after treatment.

RESULTS

Fifty-six patients underwent 119 interventions, of which 107 (90%) were technically successful. The median time from EVAR to index T2EL procedure was 37 months (interquartile range, 17-56 months), and the median follow-up time from first T2EL procedure was 27 months (interquartile range, 10-51 months). The most common index procedure was transarterial lumbar embolization (64%), followed by transarterial inferior mesenteric artery (20%), transcaval (14%), and translumbar embolization (1.8%). Thirty-three (59%) patients required further procedures for persistent aneurysm sac expansion. For subsequent T2EL interventions, the most common endovascular procedure was transarterial lumbar embolization (21%), followed by transcaval (21%), translumbar (11%), and transarterial inferior mesenteric artery embolization (8.6%). Twelve patients (21%) were found to have loss of proximal or distal seal on subsequent imaging and required graft extensions to stabilize aneurysm sac size. Ten patients (18%) ultimately underwent graft explantation or sacotomy with oversewing of the endoleak source. Freedom from any endoleak-related reintervention was 57% at 1 year and 36% at 3 years. Freedom from open treatment was 93% at 1 year and 82% at 3 years. Of the 44 patients with ≥6-month follow-up, 39 (89%) achieved clinical success. However, only 11 patients (25%) achieved clinical success without any further reintervention, and 29 patients (66%) achieved clinical success without open treatment.

CONCLUSIONS

Despite high technical success, endoleak recurrence after T2EL treatment is common, and multiple interventions are often needed to stabilize aneurysm sac size in patients diagnosed with T2EL-associated sac growth. Notably, one in five patients treated for T2ELs was discovered, on further evaluation, to have proximal or distal seal zone loss that necessitated repair to achieve sac stability. Thus, thorough assessment of all endoleak types should be performed in patients with T2ELs associated with sac growth before T2EL treatment to ensure appropriate care and to minimize ineffective interventions.

Outcomes of Onyx® Embolization of Type II Endoleaks After Endovascular Repair of Abdominal Aortic Aneurysms

BACKGROUND

Type II endoleaks (T2ELs) are common following endovascular repair of abdominal aortic aneurysms (EVAR). Embolization with ethylene vinyl alcohol copolymer (Onyx) may present an effective treatment alternative for T2ELs. Due to limited data supporting its use, we sought to analyze outcomes of Onyx embolization for T2ELs.

METHODS

Retrospective review of consecutive patients treated for T2ELs utilizing Onyx embolization agent from 2009-2018. All pre- and post-Onyx intervention CT scans were analyzed for diameter and volume changes with 3D reconstruction software. The primary outcomes were change in maximum AAA diameter and volume. Secondary outcomes included additional interventions, rupture, and mortality. A subset analysis was performed with patients with isolated T2ELs (no other types of endoleaks present).

RESULTS

We identified 85 patients (73 males, mean age 77.6 ± 7.6 years) who underwent 112 Onyx interventions. Average time to first Onyx intervention after index EVAR was 3.3 ± 2.6 years and average sac growth was 6.3 ± 6.7 mm. Patients underwent mean 1.3 Onyx interventions using a mean of 4.9 ± 4.7 ml for treatment. Three complications occurred (Onyx extravasation, colon ischemia, and access site hematoma). Mean follow-up was 2.5 ± 2.1 years after initial Onyx treatment. At the most recent follow-up, sac diameter stabilization was seen in 47% and reduction >5 mm was seen in 19%. Sac growth of >5 mm was seen in 34% of patients following the first Onyx intervention. In our subset of isolated T2EL, 72% had sac stabilization or reduction >5 mm. Four patients experienced a ruptured aneurysm (3 had active type 1 endoleaks). Rupture-free survival was 95% at 5 years, and overall survival was 54% at 5 years. Notably, increasing Onyx interventions were not associated with sac stabilization or reduction (OR 0.6, P = 0.1). On multivariable analysis, AAA sac diameter stabilization or reduction was independently associated with BMI >30 kg/m² (OR 4.2, P = 0.01) and having only 1 Onyx intervention (OR 3.8, P = 0.02).

CONCLUSIONS

Onyx for embolization of T2ELs resulted in AAA sac diameter stabilization or reduction in 66% of patients, and up to 72% in isolated T2ELs. Further, increasing Onyx interventions were not associated with either aneurysm sac stabilization or reduction. Given its similar outcomes to other embolization strategies in the literature, Onyx embolization for management of T2ELs needs to be judiciously considered, particularly for T2ELs persisting after an initial Onyx embolization intervention.

Velocities of type II endoleaks on Doppler ultrasonography predict outcome

OBJECTIVE

We sought to determine whether flow velocities measured using Doppler ultrasonography after endovascular aortic aneurysm repair (EVAR) can predict for resolution of type II endoleaks without intervention. We also assessed the relationship of the flow velocities to sac growth and the need for intervention. We hypothesized that hemodynamic properties suggesting low flow velocity would predict for resolution of type II endoleaks.

METHODS

The data from 23 patients with type II endoleaks identified on Doppler ultrasonography after EVAR from January 2014 to December 2017 were retrospectively analyzed. The 23 patients with type II endoleaks were split into two groups. Group 1 included the 13 patients with resolved endoleaks or shrinking sac size and group 2, the 10 patients with an increasing sac size or those requiring intervention to seal the endoleak because of an increased sac size. We analyzed the velocities of the endoleak nidus.

RESULTS

Doppler ultrasound velocities were significantly lower in patients with resolved type II endoleaks and those with a shrinking aneurysm sac size compared with those demonstrating an increase in aneurysm sac size (42.6 ± 25.2 cm/s vs 219.5 ± 84.1 cm/s; P < .0001). Of the 10 patients in group 2, nine had required intervention with either translumbar embolization or transarterial embolization, with only two experiencing complete resolution of the type II endoleak, despite the intervention. All patients in group 2 had had ≥1 duplex ultrasound scan with endoleak nidus velocities >100 cm/s. In contrast, no patient in group 1 had had any duplex ultrasound scan with endoleak nidus velocities >100 cm/s.

CONCLUSIONS

The Doppler ultrasound velocities of type II endoleaks might be able to predict for spontaneous resolution of type II endoleaks or increased sac growth. Type II endoleaks on Doppler ultrasonography with endoleak nidus velocities >100 cm/s can persistent, even with attempted treatment.

Transcatheter embolization with Squid, combined with other embolic agents or alone, in different abdominal diseases: a single-center experience in 30 patients

Background

Squid, as Onyx, is an ethylene-vinyl alcohol copolymer (EVOH)-based liquid embolic agent developed for neuroradiologic interventions with poor application in abdominal district. Our aim was to evaluate safety, complications, and efficacy of transcatheter embolization using the two available formulations Squid-18 and 12, in 30 patients affected by different abdominal diseases.

Results

Transcatheter embolization with Squid, combined with other embolic agents, as poly vinyl alcohol (PVA) particles, coils and amplatzer plugs, or alone (type 2 endoleak), was performed in 30 patients, as follows: 10 portal vein embolizations (PVEs), 6 arteriovenous malformations (AVMs), 5 visceral artery aneurysms (VAAs), 4 type 2 endoleaks, 3 preoperative embolizations, 1 acute arterial bleeding, 1 female varicocele. Squid was always administered using dimethyl sulfoxide (DMSO) compatible microcatheters. Technical success, 30-day clinical success and complications were assessed.

Technical success was 90%. 3 patients (2 AVMs, 1 VAA) required re-intervention successfully performed in all cases. Major complications, cases of microcatheter entrapment and DMSO-related poor pain control were not recorded. 30-day clinical success was 93.3%: in 2 patients submitted to PVE a sufficient future liver remnant (FLR) hypertrophy was not achieved.

Conclusion

Squid was successfully used with low complication rate in many abdominal diseases showing a valid embolic action either combined with other embolic agents or alone in type 2 endoleak. The availability of different formulations (Squid-18 and Squid-12) variable for viscosity makes Squid preferable to Onyx as EVOH-based liquid embolic agent, even though comparable studies in different abdominal districts with a larger cohort of patients will be necessary.