Prevention of Type II Endoleak Using the AMPLATZER Vascular Plug Before Endovascular Aneurysm Repair

Understanding Type II Endoleak: A Harmless Imaging Finding or a Silent Threat?

Type II endoleak (T2EL) represents a challenging clinical entity following endovascular abdominal aortic aneurysm repair (EVAR). Although several studies have suggested that T2ELs are related to an increased risk of aneurysm sac growth and subsequent rupture, the exact role that T2ELs play in long-term outcomes remains debatable. Understanding the pathophysiology, diagnostic modalities, and management options of T2ELs is important for patients' safety and proper resource utilization. While conservative management may be suitable for asymptomatic patients with a stable aneurysm size, interventional approaches, including transarterial embolization, direct sac puncture embolization and open conversion have been described for patients with persistent T2EL associated with sac expansion. However, more research is needed to better determine the clinical benefit of such interventions. A thorough evaluation of all endoleak types before T2EL treatment would be reasonable for patients with T2ELs associated with sac expansion. Further studies are needed to refine treatment strategies aimed at minimizing T2EL-related complications. Collaborative efforts among vascular specialists, radiologists, and researchers are of paramount importance to address this ongoing clinical challenge.

ELECT: prospective, randomized trial comparing microvascular plug versus platinum-fibered microcoils for embolization of aneurysm sac side branches before endovascular aortic aneurysm repair

BACKGROUND

Preemptive selective embolization of aneurysm sac side branches (ASSBs) has been proposed to prevent type II endoleak after endovascular aortic aneurysm repair (EVAR). This study aimed to explore if an embolization strategy using microvascular plugs (MVP) reduces intervention time and radiation dose compared to platinum-fibered microcoils. Furthermore, the effectiveness of the devices in occluding the treated artery was assessed.

METHODS

Sixty patients scheduled for EVAR underwent percutaneous preemptive embolization of ASSBs using MVPs or coils after a 1:1 randomization. Follow-up imaging was performed during aortic stentgraft implantation.

RESULTS

Overall, 170 ASSBs were successfully occluded (83 arteries by MVPs and 87 by coils) and no acute treatment failure occurred. The mean procedure time was significantly lower in the group treated with MVPs (55 ± 4 min) compared to coil occlusion (67 ± 3 min; p = 0.018), which was paralleled by a numerically lower radiation dose (119 Gy/cm2 vs. 140 Gy/cm2; p = 0.45). No difference was found for contrast agent use (34 ml MVP group vs 35 ml coil group; p = 0.87). At follow-up, reopening of lumbar arteries was seen in nine cases (four after coil embolization; five after MVPs).

CONCLUSION

Both microvascular plugs and coils can be effectively used for preemptive embolization of aneurysm sac side branches before EVAR. Use of plugs offers a benefit in terms of intervention time.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03842930 Registered 15 February 2019.

Side branch embolization before endovascular abdominal aortic aneurysm repair to prevent type II endoleak: A prospective multicenter study

PURPOSE

The purpose of the study was to evaluate the efficacy and safety of pre-emptive transcatheter arterial embolization (P-TAE) of aortic side branches to prevent type II endoleak in patients with abdominal aortic aneurysm after endovascular abdominal aneurysm repair (EVAR).

MATERIALS AND METHODS

This multicenter, prospective, single-arm trial enrolled 100 patients with abdominal aortic aneurysm from nine hospitals between 2018 and 2021. There were 85 men and 15 women, with a mean age of 79.6 ± 6.0 (standard deviation) years (range: 65-97 years). P-TAE was attempted for patent aortic side branches, including the inferior mesenteric artery, lumbar arteries, and other branches. The primary endpoint was late type II endoleak incidence at 6 months post-repair. Secondary endpoints included changes in aneurysmal sac diameter at 6- and 12 months, complications, re-intervention, and aneurysm-related mortality. Aneurysm sac changes at 6- and 12 months was compared between the late and no-late type II endoleak groups.

RESULTS

Coil embolization was successful in 80.9% (321/397) of patent aortic side branches, including 86.3% of the inferior mesenteric arteries, 80.3% of lumbar arteries, and 55.6% of other branches without severe adverse events. Late type II endoleak incidence at 6 months was 8.9% (8/90; 95% confidence interval: 3.9-16.8%). Aneurysm sac shrinkage > 5 mm was observed in 41.1% (37/90) and 55.3% (47/85) of the patients at 6- and 12-months post-EVAR, respectively. Patients with late type II endoleak had less aneurysm sac shrinkage than those without type II endoleak at 12 months (-0.2 mm vs. -6.0 mm; P = 0.040). No patients required re-intervention for type II endoleak, and no aneurysm-related mortalities occurred.

CONCLUSION

P-TAE is safe and effective in preventing type II endoleak, leading to early sac shrinkage at 12 months following EVAR.

Safety of preoperative branch embolization in patients undergoing evar

The purpose of this systematic review is to evaluate the safety of pre-endovascular abdominal aortic aneurysm repair (EVAR) embolization of aortic side branches - the inferior mesenteric artery and lumbar arteries. Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines were followed. A search of MEDLINE and DIMENSION databases identified 9 studies published from 2011 to 2021 that satisfied the inclusion and exclusion criteria. These studies were analyzed to detect the incidence of embolization-related complications. A total of 482 patients underwent preoperative aortic side branch embolization, 30 (6.2%) of whom suffered some kind of minor complication. The only major complication observed was ischemic colitis in 4 (0.82%) patients, two (0.41%) of whom died after bowel resection surgery. Regarding these findings, aortic side branch embolization seems to be a safe procedure, with very low percentages of both minor and major complications.

Preemptive Embolization of the Lumbar Arteries and Inferior Mesenteric Artery to Prevent Abdominal Aortic Aneurysm Enlargement Associated with Type 2 Endoleak Following Endovascular Aneurysm Repair

Purpose

This study aims to evaluate the efficacy of preemptive embolization (PE) of the lumbar arteries (LAs) and inferior mesenteric artery (IMA) (PELI) for preventing abdominal aortic aneurysm (AAA) enlargement associated with type 2 endoleak (T2EL).

Material and Methods

Patients who underwent endovascular aneurysm repair (EVAR) between January 2015 and December 2020 were classified into the control (without PE), IMA (PE of a patent IMA with a diameter ≥2.5 mm), and PELI (PE of patent LAs with a diameter ≥2 mm and IMA) groups. The rate of freedom from AAA enlargement following EVAR (enlargement ≥5 mm from pre-EVAR) was compared using the log-rank test. The prevalence of T2EL at 6 months and 1 year after EVAR was compared using Fisher's exact test.

Results

The cumulative rates of freedom from AAA enlargement at 54 months after EVAR (maximum observational period in the PELI group) were as follows: control group, 77.5%; IMA group, 62.5%; and PELI group, 100%. The mean CT follow-up periods of the control, IMA, and PELI groups were 46.4 ± 22.3, 31.1 ± 20.6, and 22.9 ± 15.5 months, respectively. None of the 31 patients in the PELI group experienced AAA enlargement after EVAR, whereas 2 out of the 16 patients in the IMA group and 20 out of the 98 patients in the control group had AAA enlargement. No significant differences were observed in the rate of freedom from AAA enlargement (PELI group vs. IMA group, P = 0.11; PELI group vs. control group, P = 0.11). The prevalence of T2EL was significantly lower in the PELI group than in the control group at 6 months (13.6% in PELI group vs. 42.1% in control group, P = 0.02) and 1 year (14.3% in PELI group vs. 40.0% in control group, P = 0.04).

Conclusions

PELI was significantly associated with a low prevalence of T2EL and may prevent T2EL-associated AAA enlargement.

Pre-Operative Four Dimensional Flow Sensitive Magnetic Resonance Imaging Assessment of Aortic Side Branches as a Method to Predict Risk of Type II Endoleak Resulting in Sac Enlargement After EVAR

OBJECTIVE

To predict sac enlargement with type II endoleak (ELII) before endovascular aneurysm repair (EVAR) using four dimensional flow sensitive magnetic resonance imaging (4D flow MRI).

METHODS

A single centre retrospective analysis of prospectively collected data was conducted. Patients with an abdominal aortic aneurysm (AAA) who underwent EVAR between 2013 and 2019 were included. Aortic branches occluded pre-EVAR, and patients with endoleaks other than ELII were excluded. The aortic branch diameter, peak flow velocity (PFVe), and amplitude of the dynamics of flow volume (AFV) were measured in each aortic branch pre-EVAR. Total flow volume per minute (TFV/min), defined as the sum of AFV/min, was calculated in each case. According to computed tomography findings one year post-EVAR, the aortic branches and patients were divided into patent vessel and occluded vessel groups and sac expanding and non-expanding groups. PFVe, AFV/min, and TFV/min were analysed via receiver operating characteristic curve analysis.

RESULTS

The patent aortic branches pre-EVAR (69 inferior mesenteric arteries [IMAs]; 249 lumbar arteries [LAs]) of 100 patients were included. Patent IMAs (n = 14) and occluded IMAs (n = 55), patent LAs (n = 23) and occluded LAs (n = 226), and expanding (n = 9) and non-expanding (n = 91) groups were compared, respectively. No statistically significant difference was observed in branch diameters (IMA; patent, 2.5 ± 0.8 mm, occluded, 2.5 ± 0.8 mm, p < .78 and LA; patent, 1.5 ± 0.3 mm, occluded, 1.5 ± 0.4 mm, p < .35). PFVe (IMA; patent, 262.6 mm2/sec, occluded, 183.4 mm2/sec and LA; patent, 142.6 mm2/sec, occluded, 47.7 mm2/sec) and AFV/min (IMA; patent, 8.4 mL, occluded, 5.2 mL and LA; patent, 4.2 mL, occluded, 1.4 mL) were higher in the patent vessel group (p < .050). TFV/min was statistically significantly higher in the expanding group (24.1 mL/min) than in the non-expanding group (7.0 mL/min) (p < .010).

CONCLUSION

Pre-EVAR haemodynamic analyses using 4D flow MRI were useful to detect aortic branches responsible for ELII and to predict AAA cases with sac enlargement. This analysis suggests a new strategy for pre-EVAR aortic branch embolisation.

Pre-Emptive Embolization of the Aneurysm Sac or Aortic Side Branches in Endovascular Aneurysm Repair: Meta-Analysis and Trial Sequential Analysis of Randomized Controlled Trials

BACKGROUND

To investigate outcomes of pre-emptive embolization of the aneurysm sac or aortic side branches in endovascular aneurysm repair (EVAR).

METHODS

The review was reported as per Preferred Reporting Items for Systematic reviews and Meta-Analyses 2020 with a preregistered protocol. Bibliographic sources (MEDLINE, Embase, and CENTRAL) were searched using subject headings and free text terms. Randomized controlled trials comparing EVAR with versus without embolization were included. Pooled estimates of dichotomous outcomes were calculated using odds ratio (OR) or risk difference (RD) and 95% confidence interval (CI) applying the Mantel-Haenszel method. Continuous outcomes were summarized using mean difference (MD) and 95% CI applying the inverse variance method. The certainty of evidence was appraised with the Grading of Recommendations Assessment, Development, and Evaluation framework. Version 2 of the Cochrane tool was used to assess the risk of bias. Trial sequential analysis assumed alpha = 5% and power = 80%.

RESULTS

Four randomized controlled trials were included. No significant difference was found in aneurysm-related mortality (RD 0.00, 95% CI -0.03 to 0.03), overall mortality (OR 1.85, 95% CI 0.42-8.13), aneurysm rupture (RD 0.00, 95% CI -0.03 to 0.03), type II endoleak-related reintervention (RD -0.07, 95% CI -0.21 to 0.06), procedure time (MD 20.12, 95% CI -11.54 to 51.77), or fluoroscopy time (MD 11.17, 95% CI -11.22 to 33.56). Patients with pre-emptive embolization had significantly lower odds of type II endoleak (OR 0.45, 95% CI 0.26-0.78) and sac expansion (OR 0.19, 95% CI 0.07-0.52). The risk of bias was high for all outcomes. The certainty of evidence was very low for all outcomes, except for type II endoleak, for which it was low. Trial sequential analysis showed an inconclusive result for overall mortality and type II endoleak-related reintervention but confirmed the advantage of embolization in reducing type II endoleak and sac expansion.

CONCLUSIONS

Limited, low certainty data suggest pre-emptive embolization confers no clinical benefits in EVAR.

Routine Inferior Mesenteric Artery Embolisation is Unnecessary Before Endovascular Aneurysm Repair

OBJECTIVE

A type II endoleak is the most common complication during surveillance after endovascular aneurysm repair (EVAR), and a patent inferior mesenteric artery (IMA) is a known risk factor for an endoleak. The effect of routine IMA embolisation prior to EVAR on overall outcome is unknown. The aim of the study was to compare two strategies: routine attempted IMA embolisation prior to EVAR (strategy in centre A) and leaving the IMA untouched (strategy in centre B).

METHODS

Patients were treated with EVAR in two centres during the period 2005 - 2015, and the data were reviewed retrospectively. The primary endpoints were re-intervention rate due to type II endoleaks and the late IMA embolisation rate. Secondary endpoints included EVAR related re-intervention, sac enlargement, aneurysm rupture, and open conversion rates.

RESULTS

Strategy A was used to treat 395 patients. The IMA was patent in 268 (67.8%) patients, and embolisation was performed in 164 (41.5%). The corresponding figures for strategy B were 337 patients with 279 (82.8%) patent IMAs, two (0.6%) of which were embolised. The mean duration of follow up was 70 months for strategy A and 68.2 months for strategy B. The re-intervention rates due to a type II endoleak were 12.9% and 10.4%, respectively (p = .29), with no significant difference in the rate of re-interventions to occlude a patent IMA (2.0% and 4.7%, respectively; p = .039). The EVAR related re-intervention rate was similar, regardless of strategy (24.1% and 24.6%, respectively; p = .93). Significant sac enlargement was seen in 20.3% of cases treated with strategy A and in 19.6% treated with strategy B (p = .82). The rupture and conversion rates were 2.5% and 2.1% (p = .69) and 1.0% and 1.5% (p = .40), respectively.

CONCLUSION

The strategy of routinely embolising the IMA does not seem to yield any significant clinical benefit and should therefore be abandoned.

Results from the First-in-Human Study of the Caterpillar™ Arterial Embolization System

PURPOSE

To assess occlusion success and adverse events associated with the use of a self-expanding device for peripheral artery embolization.

METHODS

This prospective, single-arm, feasibility study was conducted using the Caterpillar™ Arterial Embolization Device composed of opposing nitinol fibers and a flow-occluding membrane. Twenty patients (24 embolization sites) were treated at four investigational centers in New Zealand and Australia and followed for 30 days. Embolization sites included mesenteric, accessory renal, and iliac arteries and their branches. Primary outcome measures were peri-procedural occlusion confirmed by angiography and freedom from device-related serious adverse events (SAEs) at 30 days. Secondary observations included time to occlusion and assessment of adverse events.

RESULTS

Peri-procedural occlusion was 100%, and freedom from a device-related SAE was 94.7% at 30 days. One patient had abdominal bloating that required hospitalization deemed possibly related to the device or procedure. Twenty-two of 24 embolization sites were occluded with one device (91.7%). Mean procedure duration was 11.7 ± 8.6 min (device deployment time: 1.8 ± 1.0 min), and mean fluoroscopy time was 241 ± 290.7 s. All embolization sites occluded during the procedure with 62.5% occluded within three minutes and 91.6% occluded within ten minutes. No devices migrated or required re-embolization. Freedom from device- and procedure-related adverse events was 84.2%. One patient died from aortic rupture during a subsequent adjunctive abdominal aortic endovascular procedure deemed unrelated to the embolization device or procedure.

CONCLUSIONS

This first-in-human study of the Caterpillar embolization device achieved peri-procedural occlusion in all patients with a 94.7% freedom from device-related SAE at 30 days.

LEVEL OF EVIDENCE

Level 2b-prospective, multicenter, single-arm, first-in-human clinical study. Pre-specified endpoints were analyzed using descriptive statistics.

An updated systematic review and meta-analysis of pre-emptive aortic side branch embolization to prevent type II endoleaks after EVAR

OBJECTIVE

Pre-emptive embolization of aortic side branches may be effective in preventing type II endoleaks (T2EL) based on a previous systematic review and meta-analysis by our group. Data up to 2019 was, however, only based on retrospective studies. The aim of the current study was to update the meta-analysis and evaluate the current evidence on this treatment strategy.

METHODS

A systematic literature search was performed with the same keywords and strategies used in the previous study. The complementary search included all articles published from January 1, 2019, through May 29, 2022. The incidence of aneurysm sac growth was the primary outcome of interest.

RESULTS

Four new studies were identified, including one randomized controlled study and one nationwide registry-based retrospective study. Overall, the incidence of sac size enlargement was 4.3% in the embolization group compared with 6.8% in the control group (odds ratio [OR], 0.38; 95% confidence interval [CI], 0.26-0.55), the incidence of T2EL was 19.7% vs 37.4% (OR, 0.38; 95% CI, 0.30-0.47), and the incidence of reintervention for T2EL was 1.2% vs 11.2% (OR, 0.12; 95% CI, 0.06-0.23).

CONCLUSIONS

Current evidence confirms lower incidence of aneurysm sac growth, T2EL, and reinterventions when pre-emptive embolization of aortic side branches is performed in conjunction with endovascular aneurysm repair, compared with no embolization. However, a higher level of evidence is still required to support a broad change of practice, including data on cost-effectiveness and on the potential effect on rupture.

Systematic review and network meta-analysis of pre-emptive embolization of the aneurysm sac side branches and aneurysm sac coil embolization to improve the outcomes of endovascular aneurysm repair

Objective

Previous reports have revealed a high incidence of type II endoleak (T2EL) after endovascular aneurysm repair (EVAR). The incidence of T2EL after EVAR is reduced by pre-emptive embolization of aneurysm sac side branches (ASSB) and aneurysm sac coil embolization (ASCE). This study aimed to investigate whether different preventive interventions for T2EL were correlated with suppression of aneurysm sac expansion and reduction of the re-intervention rate.

Methods

The PubMed, Web of Science, MEDLINE and Embase databases, and conference proceedings were searched to identify articles on EVAR with or without embolization. The study was developed in line with the Participants, Interventions, Comparisons, Outcomes, and Study design principles and was conducted and reported in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines. We used network meta-analysis based on multivariate random-effects meta-analysis to indirectly compare outcomes of different strategies for embolization during EVAR.

Results

A total of 31 studies met all inclusion criteria and were included in the qualitative and quantitative syntheses. The included studies were published between 2001 and 2022 and analyzed a total of 18,542 patients, including 1,882 patients who received prophylactic embolization treatment during EVAR (experimental group) and 16,660 who did not receive prophylactic embolization during EVAR (control group). The effect of pre-emptive embolization of the inferior mesenteric artery (IMA) (IMA-ASSB) in preventing T2EL was similar (relative risk [RR] 1.01, 95% confidence interval [CI] 0.38–2.63) to the effects of non-selective embolization of ASSB (NS-ASSB) and ASCE (RR 0.88, 95% CI 0.40–1.96). IMA-ASSB showed a better clinical effect in suppressing the aneurysm sac expansion (RR 0.27, 95% CI 0.09–2.25 compared with NS-ASSB; RR 0.93, 95% CI 0.16–5.56 compared with ASCE) and reducing the re-intervention rate (RR 0.34, 95% CI 0.08–1.53 compared with NS-ASSB; RR 0.66, 95% CI 0.19–2.22 compared with ASCE). All prophylactic embolization strategies improved the clinical outcomes of EVAR.

Conclusion

Prophylactic embolization during EVAR effectively prevents T2EL, suppresses the aneurysm sac expansion, and reduces the re-intervention rate. IMA embolization demonstrated benefits in achieving long-term aneurysm sac stability and lowering the risk of secondary surgery. NS-ASSB more effectively reduces the incidence of T2EL, while IMA embolization alone or in combination with ASCE enhances the clinical benefits of EVAR. In addition, as network meta-analysis is still an indirect method based on a refinement of existing data, more studies and evidence are still needed in the future to establish more credible conclusions.

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.

Effectiveness of collateral arteries embolization before endovascular aneurysm repair to prevent type II endoleaks: A systematic review and meta-analysis

OBJECTIVES

This study aimed to evaluate the effect of preventive collateral arteries embolization before endovascular aneurysm repair (EVAR) to reduce type II endoleaks (T2EL), aneurysm enlargement, and re-interventions.

METHODS

A comprehensive search of PubMed, MEDLINE, Web of Science, and Embase was conducted to identify articles in English, related to preventive collateral arteries embolization before EVAR, published until October 2020.

RESULTS

A total of 12 relevant studies, including 11 retrospective studies and one randomized controlled trial, were identified and fulfilled the specified inclusion criteria. A total of 1706 patients in 11 studies were involved in the meta-analysis. The overall incidence of T2EL was 17.3% in the embolization group vs. 34.5% in the control group (OR 0.36, p < 0.01). The incidence of persistent T2EL was 15.3% vs. 30.0% (OR 0.37, p < 0.01). Five studies reported the incidence of sac enlargement, with the rate 10.2% vs. 24.9% (OR 0.25, p < 0.01). Nine studies reported T2EL related re-interventions, and it was 1.3% in the embolization group and 10.4% in control (OR 0.14, p < 0.01). The technical success of collateral arteries embolization was 92.1% (455/494) in the 12 studies. 1.2% (10/829) patients suffered a mild complication of collateral arteries embolization, and 2/829 patients died because of the embolization.

CONCLUSION

Collateral arteries embolization is a promising measure to prevent the occurrence of T2EL, sac enlargement, and re-intervention. High-quality studies need to be conducted to provide stronger evidence-based medical suggestions about the embolize operation.

The use of the Amplatzer Vascular Plug in the prevention of endoleaks during abdominal endovascular aneurysm repair: A systematic literature review on current applications

OBJECTIVES

The Amplatzer Vascular Plug (AVP) is a vascular occlusion device designed to provide optimal embolization in several fields of the endovascular surgery. A full literature review was conducted to analyze AVPs in comparison with coils for the prevention of endoleaks during endovascular abdominal aortic aneurysm repair.

METHODS

A systematic review was designed under PRISMA statement guidelines for systematic reviews and meta-analyses. The results were updated with a subsequent electronic search using Medline and Scopus databases up to December 2019.

RESULTS

Eighteen articles making this comparison were found. In 79.7% of the cases, the target vessel was the internal iliac artery; in 1.6%, the common iliac artery; and in 16.7%, the inferior mesenteric artery. Risk of complications (buttock claudication, groin hematoma, endoleaks, and erectile dysfunction) after AVP was low. A cost comparison revealed that the mean cost for coils was around US$2262, while the average cost for the AVP was US$310.

CONCLUSIONS

The AVP is an effective and safe device for occluding peripheral vessels, proved to have lower complications rates. Compared with coil embolization, the AVP technique is potentially associated with lower procedural costs.

Outcomes of Preventive Embolization of the Inferior Mesenteric Artery during Endovascular Abdominal Aortic Aneurysm Repair

PURPOSE

To evaluate the impact of preemptive inferior mesenteric artery (IMA) embolization on outcomes of endovascular abdominal aortic aneurysm (AAA) repair (EVAR).

MATERIALS AND METHODS

From January 2015 to July 2017, all patients undergoing elective EVAR or fenestrated EVAR (F-EVAR) for asymptomatic AAA in a single tertiary hospital were retrospectively included. Three groups of patients were defined: patients with a patent IMA who underwent embolization during EVAR/F-EVAR (group 1), those with a patent IMA who did not undergo embolization during EVAR/F-EVAR (group 2), and those with a chronically occluded IMA (group 3). Preoperative aortic morphology, demographics, and procedural details were recorded. Aneurysmal growth (≥5 mm), reintervention, and overall mortality rates were analyzed using multivariate proportional hazard multivariate modeling. Propensity scores were constructed, and inverse probability weighting was applied to a new set of multivariate analyses to perform a sensitivity analysis.

RESULTS

A total of 266 patients (male, 95% [n = 249]) with a median age of 70 (65-77) years were included, with F-EVAR procedures comprising 87 (32.7%) of the interventions. There were 52, 142, and 72 patients in groups 1, 2, and 3, respectively. Changes in aneurysmal sac size did not differ between groups, nor did overall survival or reintervention rates at 24 months. IMA embolization was not identified as an independently protective factor for aneurysmal growth during follow-up (relative risk [RR] = 2.82/mm [0.96-8.28], P = .060), whereas accessory renal arteries (RR = 5.07/mm [1.72-14.96], P = .003) and a larger preoperative aneurysmal diameter (RR = 1.09/mm [1.03-1.15], P = .004) were independent risk factors for sac enlargement.

CONCLUSIONS

Preventive embolization of the IMA during EVAR or F-EVAR did not promote aneurysmal sac shrinking or decrease the reintervention rate at 2-year follow-up.

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.)

Does Endovascular Abdominal Aortic Repair Change Psoas Muscle Volume?

BACKGROUND

Because endovascular abdominal aortic repair (EVAR) lowers the lumbar arterial blood flow, we hypothesized that the volume of the psoas muscle decreases after surgery. When internal iliac artery (IIA) embolization is performed, the lumbar arterial blood flow further decreases; therefore, we also hypothesized that the decrease in the volume of the psoas muscle becomes more significant. This study was performed to assess the volume change in the psoas muscle after EVAR.

METHODS

Fifty-three consecutive patients who underwent EVAR from January 2016 to December 2016 were included. The psoas muscle volume was measured by preoperative and postoperative computed tomography (CT). Postoperative CT scans were performed 6-12 months after EVAR. Axial CT images with a 2-mm slice thickness were used to measure the psoas muscle volume. Data were transferred to a 3-dimensional workstation, and the psoas muscle volume was measured.

RESULTS

In the EVAR group, the volume of the psoas muscle decreased by an average of 5.8 mL (4.6%) from 114.8 ± 32.0 mL preoperatively to 109.0 ± 30.3 mL postoperatively (P < 0.01). There was a significant difference in the change in the psoas muscle volume between patients with and without IIA embolization (embolization group: preoperative 118.1 ± 31.0 mL, postoperative 107.5 ± 29.2 mL, mean volume change rate -8.8%; nonembolization group: preoperative 114.0 ± 32.3 mL, postoperative 109.4 ± 30.7 mL, mean volume change rate -3.6%; P < 0.05).

CONCLUSIONS

The psoas muscle volume is reduced with EVAR. Moreover, when the IIA is embolized, the psoas muscle volume is further reduced.

Sac Embolization and Side Branch Embolization for Preventing Type II Endoleaks After Endovascular Aneurysm Repair: A Meta-analysis

Purpose:To investigate the efficacy and safety of preoperative side branch embolization or intraoperative sac embolization for preventing type II endoleaks after endovascular aneurysm repair (EVAR). Materials and Methods: A systematic literature search of MEDLINE and EMBASE was performed to identify studies that evaluated the outcomes of sac embolization vs no embolization or side branch embolization vs no embolization in patients who received EVAR. Among the 904 studies screened, 17 studies with 2084 participants were included in this review. Outcome measures included the type II endoleak rate, the reintervention rate for type II endoleaks, the incidence of types I/III endoleaks, and the rate of complications. Fixed (no heterogeneity) or random effects models were constructed for each outcome; the results are presented as the odds ratio (OR) with 95% confidence interval (CI). Results: The sac embolization group had significantly lower type II endoleak (OR 0.21, 95% CI 0.13 to 0.34, p<0.001) and reintervention (OR 0.15, 95% CI 0.07 to 0.33, p<0.001) rates than the no embolization group. No significant differences between the 2 groups were found for the type I/III endoleak rate (OR 0.57, 95% CI 0.23 to 1.37, p=0.21) or complication rate (OR 1.22, 95% CI 0.32 to 4.70, p=0.77). Compared with no embolization, side branch embolization was also associated with a decrease in type II endoleak (OR 0.35, 95% CI 0.21 to 0.60, p<0.001) and reinterventions (OR 0.10, 95% CI 0.04 to 0.27, p<0.001). One severe procedure-related complication (fatal colon ischemia) was reported in the side branch embolization group. Conclusion: Sac embolization and side branch embolization are safe and effective in preventing type II endoleaks. Further randomized trials are needed to directly compare the clinical outcomes of these procedures.

Preoperative Inferior Mesenteric Artery Embolization is a Cost-effective Technique that May Reduce the Rate of Aneurysm Sac Diameter Enlargement and Reintervention After EVAR

BACKGROUND

Type II endoleaks are the most common complications after endovascular repair of abdominal aortic aneurysms (EVARs). Some studies have shown the benefit of preventive inferior mesenteric artery (IMA) embolization, but its efficacy and cost-effectiveness continue to be controversial. The aim of this study was to evaluate the efficacy of this procedure on the increase in aneurysmal sac diameter during follow-up.

MATERIALS AND METHODS

All consecutive patients who underwent the embolization of the IMA before EVAR in our center, between January 2014 and July 2016, were included. We retrospectively compared the diameter of the aortic aneurysm sac, the rate of endoleak and reinterventions, and the theoretical cost of management between these patients (group 2) and a historical cohort of patients treated for EVAR before January 2014 who did not undergo prior IMA embolization (group 1).

RESULTS

Two hundred twenty-four patients were retrospectively analyzed. After exclusion, we compared a group of 37 embolized patients with a control group of 46 patients. The rate of enlargement in the aneurysmal sac diameter was significantly higher in the control group at 2 years (27.9% vs. 4.3%, P = 0.025). The type II endoleak rate at 2 years was significantly higher in the control group (53.1% vs. 18.2%, P = 0.012), as was the aneurysm-related reintervention rate (31.1% vs. 8.1%, P = 0.013). Multivariate analysis confirmed these results. At 2 years of follow-up, there was no difference in the overall cost of patient management between the 2 groups.

CONCLUSIONS

Preventive IMA embolization is an effective, reliable, and cost-effective technique that seems to reduce the rate of the aneurysmal sac diameter enlargement, type II endoleak, and reinterventions after EVAR.

Flow dynamics of type II endoleaks can determine sac expansion after endovascular aneurysm repair using four-dimensional flow-sensitive magnetic resonance imaging analysis

OBJECTIVE

The objective of this study was to investigate the hemodynamic parameters of type II endoleaks (T2ELs) to predict sac expansion using four-dimensional flow-sensitive magnetic resonance imaging (4D-flow MRI) analysis.

METHODS

Patients who underwent endovascular aneurysm repair (EVAR) and were diagnosed with a T2EL were included in the study. Using 4D-flow MRI at 7 days, the peak flow velocity and amplitude of dynamics of blood flow per minute were measured in each T2EL vessel. The peak flow velocity was defined as the maximum of the absolute value of the blood flow velocity. The amplitude of dynamics of blood flow in the tributary arteries was defined as the sum of the absolute values of the inflow and outflow volume in each vessel. The amplitude of dynamics of blood flow in the tributary arteries per sac was calculated in each sac. The aneurysm sac diameter was measured by computed tomography (CT) at 1 year. The patients were divided into two groups according to the presence or absence of sac expansion.

RESULTS

Of 155 patients who underwent EVAR, both CT angiography and 4D-flow MRI were performed in 107 patients at 7 days after EVAR. Among them, 39 (36.4%) were found to have a T2EL, of whom 28 were re-evaluated with CT angiography and 4D-flow at 1 year; 7 patients had expanding sacs (expanding group), whereas 21 had nonexpanding sacs (not-expanding group). At 7 days, 28 patients had 80 T2EL vessels detected by 4D-flow MRI, of which 39 vessels (48.8%) had stopped flowing at 1 year (transient vessels); 41 vessels (51.3%) had sustained flow (persistent vessels). The persistent vessels had significantly larger peak flow velocity and amplitude of dynamics of blood flow. The comprehensive analysis of T2EL vessels per sac identified that the amplitude of dynamics of blood flow in the tributary arteries per sac was significantly higher in the expanding group than in the not-expanding group. A receiver operating characteristic curve analysis revealed that the sensitivity and specificity of sac enlargement at a cutoff value of 3750 mm³/min were 85.7% and 76.2%, respectively.

CONCLUSIONS

The fate of aneurysm sacs with T2ELs after EVAR has remained difficult to predict. A comprehensive analysis of concurrent multiple T2EL vessels using 4D-flow MRI analysis may enable prediction of the sac expansion after EVAR.

Type II Endoleak After Endovascular Aortic Aneurysm Repair Using the Endurant Stent Graft System for Abdominal Aortic Aneurysm with Occluded Inferior Mesenteric Artery

PURPOSE

To evaluate the incidence of type II endoleak (EL-II) and aneurysm enlargement after endovascular aneurysm repair (EVAR) using the Endurant stent graft in patients with abdominal aortic aneurysm (AAA) with occluded inferior mesenteric artery (IMA).

MATERIALS AND METHODS

Between 2012 and 2017, 103 patients who underwent EVAR using the Endurant stent graft for AAA with occluded IMA (50 patients with prophylactic embolized IMA and 53 with spontaneous occluded IMA) were retrospectively reviewed. The incidence of EL-II and aneurysm enlargement was evaluated. Predictive factors for persistent EL-II were evaluated based on patient characteristics, preprocedural anatomical characteristics, intraprocedural details, and postprocedural complications.

RESULTS

Incidence rates of early EL-II and persistent EL-II were 6.8% (7/103 patients) and 4.9% (5/103 patients), respectively. Aneurysm enlargement was found in 10 patients (9.7%), including all 5 patients with persistent EL-II, 3 with de novo EL-II, and 2 with no EL-II. The rates of freedom from aneurysm enlargement at 1, 2, and 3 years were 98.7%, 97.0%, and 93.1% for the group without persistent EL-II, and 80.0%, 60.0%, and 20.0% for the group with persistent EL-II (p < 0.001), respectively. The maximum aneurysm diameter (odds ratio (OR), 1.16; 95% confidence interval (CI), 1.01-1.34; p = 0.0362) and the number of patent lumbar arteries (OR, 2.72; 95% CI, 1.07-6.90; p = 0.0357) were predictive of persistent EL-II.

CONCLUSIONS

The incidence of EL-II after EVAR using the Endurant stent graft for AAA with occluded IMA was low, but most early EL-II persisted and resulted in aneurysm enlargement. Level of Evidence Level 4, Case Series.

Effectiveness of Embolization of Inferior Mesenteric Artery to Prevent Type II Endoleak Following Endovascular Aneurysm Repair: A Review of the Literature

Type II endoleak is a common complication that develops after endovascular aneurysm repair. Patients with type II endoleak, which has persisted for 6 months, have a significantly higher rate of aneurysmal sac enlargement, reintervention, and rupture. To date, several studies have examined the effectiveness of preoperative embolization of branch vessels for the prevention of type II endoleak. Particularly, the embolization of the large inferior mesenteric artery (IMA) seems to be a precise, safe, and effective method. IMA is a significant risk factor for type II endoleak. However, there is currently no strong evidence to prove which patients would benefit from preventive IMA embolization. In addition, considering the incidence of type II endoleak and the adverse event rate, routine embolization seems to be unreliable and time-consuming. Moreover, previous reports of preoperative IMA embolization were retrospective. Thus, prospective and randomized studies are necessary so that the usefulness of IMA embolization can be proved and the potential benefits can be assessed. To establish preventive IMA embolization as one of the effective therapeutic strategies to prevent type II endoleak and to maximize its therapeutic effect, we should provide a wide range of therapeutic strategies to suit the state of the patient.

Evaluation and Coil Embolization of the Aortic Side Branches for Prevention of Type II Endoleak after Endovascular Repair of Abdominal Aortic Aneurysm

Objectives: Aneurysm shrinkage after EVAR is the strong factor of favorable outcomes after endovascular abdominal aortic aneurysm repair (EVAR), and type II endoleaks is the risk factor of no aneurysm shrinkage or aneurysm enlargement in the long term. In this study, we evaluate the aortic side branches relate to early postoperative type II endoleak, and performed coil embolization for those vessels for prevention of type II endoleak.

Methods: Patency and diameter of aortic side branches including inferior mesenteric artery (IMA) and lumbar artery (LA) were evaluated in 56 consecutive patients with abdominal aortic aneurysm who were scheduled for EVAR. Coil embolization with Interlock was performed in 24 patients during EVAR for all patent IMA and LA with maximal diameter more than 2.0 mm. Computed tomography was performed one week after EVAR for evaluation of endoleak.

Results: In patients with IMA more than 2.5 mm in diameter, the frequency of type II endoleak was approximately 90% regardless of the number of patent LA. In case with patent IMA less than 2.5 mm or with 2 or more patent LA larger than 2.0 mm, the frequency of type II endoleak was 46 to 67%. Coil embolization for IMA was successfully performed in 15/16 patients (94%). Coil embolization of LA was performed for patent LA larger than 2.0 mm and 29 out of 45 LA (64%) were successfully occluded. There was no perioperative complication associated with coil embolization. The frequency of type II endoleak was significantly lower in patients with coil embolization than those without coil embolization (4.2% vs 58.9%, p<0.0001).

Conclusion: Patent IMA and LA in diameter larger than 2.0 mm were associated with type II endoleak one week after EVAR, and coil embolization with Interlock during EVAR is safe and effective procedure to prevent type II endoleak. (This is a translation of Jpn J Vasc Surg 2016; 25: 321–328.)

Preoperative Inferior Mesenteric Artery Embolization: A Valid Method to Reduce the Rate of Type II Endoleak after EVAR?

BACKGROUND

Type II endoleak is the most commonly encountered endoleak after endovascular abdominal aortic aneurysm repair (EVAR). Some have advocated preoperative inferior mesenteric artery (IMA) embolization as a valid method for reducing the incidence of this endoleak, but controversies exist. We sought to demonstrate the impact of IMA embolization using a meta-analysis of currently available studies combined with our own experience.

METHODS

We conducted an institutional review board-approved, retrospective analysis of all patients undergoing IMA embolization before EVAR between the years 2010 and 2015 and used as a control a similar group of patients with patent IMA. We divided patients from our own experience and 5 other studies into 2 groups: those who did not undergo IMA embolization (control) before EVAR and those who did. Rates of type II endoleaks, aneurysm sac regression, and secondary interventions were analyzed.

RESULTS

A total of 620 patients from 6 studies were analyzed, including 258 patients who underwent an attempted IMA embolization before EVAR with a cumulative success rate of 99.2% (range, 93.8% to 100%). There was 1 fatality associated with IMA embolization. A meta-analysis showed that preoperative IMA embolization protected against type II endoleaks compared to the control group (odds ratio [OR], 0.31 [0.17-0.57]; P < 0.001, I² = 43%). Furthermore, the rate of secondary intervention was significantly lower in the treatment group (OR, 0.12 [0.004-0.36]; P < 0.001, I² = 0%). After IMA embolization, type II endoleak resulted from patent lumbar arteries in all 62 patients with persistent endoleak.

CONCLUSIONS

Preoperative embolization of the IMA protects against the development of type II endoleaks and secondary interventions and may potentially lead to a rapid aneurysm sac regression. The procedure can be performed with a high technical success rate and minimal complications and should be considered in patients with IMA >3 mm before EVAR. A randomized trial, however, is required to clearly delineate the clinical significance of this technique.

Type II endoleaks: challenges and solutions

Type II endoleaks are the most common endovascular complications of endovascular abdominal aortic aneurysm repair (EVAR); however, there has been a divided opinion regarding their significance in EVAR. Some advocate a conservative approach unless there is clear evidence of sac expansion, while others maintain early intervention is best to prevent adverse late outcomes such as rupture. There is a lack of level-one evidence in this challenging group of patients, and due to a low event rate of complications, large numbers of patients would be required in well-designed trials to fully understand the natural history of type II endoleak. This review will discuss the imaging, management, and outcome of patients with isolated type II endoleaks following infra-renal EVAR.

The Amplatzer Vascular Plug: Review of Evolution and Current Applications

The Amplatzer Vascular Plug (AVP) was created for peripheral embolization as a modification of the family of Amplatz septal occluders used in the treatment of congenital heart malformations. The device has evolved over the years and multiple versions have been launched into the market. Each of the versions of the device has some important modifications in terms of the size of the introducer's system, number of layers, and resultant thrombogenicity. It is very important for the operator to become familiar with the unique features of the AVP, and to understand the advantages and limitations of each model in the AVP family to achieve an optimal embolic result. The purpose of this article is to review the evolution and current clinical applications of the AVP in the field of interventional radiology, with emphasis on the advantages and limitations of this device in comparison with other embolization agents.

Outcomes of endovascular aneurysm repair with contemporary volume-dependent sac embolization in patients at risk for type II endoleak

OBJECTIVE

The aim of this study was to evaluate outcomes of intraoperative aneurysm sac embolization during endovascular aneurysm repair (EVAR) in patients considered at risk for type II endoleak (EII), using a sac volume-dependent dose of fibrin glue and coils.

METHODS

Between January 2012 and December 2014, 126 patients underwent EVAR. Based on preoperative computed tomography evaluation of anatomic criteria, 107 patients (85%) were defined as at risk for EII and assigned to randomization for standard EVAR (group A; n = 55, 44%) or EVAR with intraoperative sac embolization (group B; n = 52, 42%); the remaining 19 patients (15%) were defined as at low risk for EII and excluded from the randomization (group C). Computed tomography scans were evaluated with OsiriX Pro 4.0 software to obtain aneurysm sac volume. Freedom from EII, freedom from EII-related reintervention, and aneurysm sac volume shrinkage at 6, 12, and 24 months were compared by Kaplan-Meier estimates. Patients in group C underwent the same follow-up protocol as groups A and B.

RESULTS

Patient characteristics, Society for Vascular Surgery comorbidity scores (0.99 ± 0.50 vs 0.95 ± 0.55; P = .70), and operative time (149 ± 50 minutes vs 157 ± 39 minutes; P = .63) were similar for groups A and B. Freedom from EII was significantly lower for group A compared with group B at 3 months (58% vs 80%; P = .002), 6 months (68% vs 85%; P = .04), and 12 months (70% vs 87%; P = .04) but not statistically significant at 24 months (85% vs 87%; P = .57). Freedom from EII-related reintervention at 24 months was significantly lower for group A compared with group B (82% vs 96%; P = .04). Patients in group B showed a significantly overall mean difference in aneurysm sac volume shrinkage compared with group A at 6 months (-11 ± 17 cm(3) vs -2 ± 14 cm(3); P < .01), 12 months (-18 ± 26 cm(3) vs -3 ± 32 cm(3); P = .02), and 24 months (-27 ± 25 cm(3) vs -5 ± 26 cm(3); P < .01). Patients in group C had the lowest EII rate compared with groups A and B (6 months, 5%; 12 months, 6%; 24 months, 0%) and no EII-related reintervention.

CONCLUSIONS

This randomized study confirms that sac embolization during EVAR, using a sac volume-dependent dose of fibrin glue and coils, is a valid method to significantly reduce EII and its complications during early and midterm follow-up in patients considered at risk. Although further confirmatory studies are needed, the faster aneurysm sac volume shrinkage over time in patients who underwent embolization compared with standard EVAR may be a positive aspect influencing the lower EII rate also during long-term follow-up.

Is Inferior Mesenteric Artery Embolization Indicated Prior to Endovascular Repair of Abdominal Aortic Aneurysm?

Type II endoleak is a common condition occurring after endovascular repair of abdominal aortic aneurysms (EVAR), and may result in aneurysm sac growth and/or rupture in a small number of patients. A prophylactic strategy of inferior mesenteric artery (IMA) embolization before EVAR has been advocated, however, the benefits of this strategy are controversial. A clinical vignette allows the authors to summarize the available data about this issue and discuss the possible benefits and risks of prophylactic IMA embolization before EVAR. The authors performed a meta-analysis of available data which showed that the pooled rate of type II endoleak after IMA embolization was 19.9% (95% CI 3.4-34.7%, I2 93%) whereas it was 41.4% (95% CI 30.4-52.3%, I2 76%) in patients without IMA embolization (5 studies including 596 patients: p < .0001, OR 0.369, 95% CI 0.22-0.61, I2 27%). Since treatment for type II endoleaks is needed in less than 20% of cases and this complication can be treated successfully in 60-70% of cases resulting in an aneurysm rupture risk of 0.9%, these data indicate that embolization of patent IMA may be of no benefit in patients undergoing EVAR.

Essentials of endovascular abdominal aortic aneurysm repair imaging: postprocedure surveillance and complications

OBJECTIVE

Lifelong postprocedural imaging surveillance is necessary after endovascular abdominal aortic aneurysm repair (EVAR) to assess for complications of endograft placement, as well as device failure and continued aneurysm growth. Refinement of the surveillance CT technique and development of ultrasound and MRI protocols are important to limit radiation exposure.

CONCLUSION

A comprehensive understanding of EVAR surveillance is necessary to identify life-threatening complications and to aid in secondary treatment planning.