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

Five-year follow-up of randomized clinical trial for pre-emptive inferior mesenteric artery embolization during endovascular aneurysm repair

OBJECTIVE

Type II endoleak (T2EL) is the most common type of endoleak after endovascular aneurysm repair (EVAR) and a common indication for reintervention due to late sac enlargement. Although pre-emptive embolization of the inferior mesenteric artery (IMA) has been proposed to prevent this, no studies have prospectively demonstrated its efficacy. This study aimed to prove the validity of IMA embolization during EVAR in selective cases by analyzing the mid-term outcomes of a randomized clinical trial (RCT).

METHODS

This single-center, parallel-group, non-blinded RCT included participants at high risk of T2EL, characterized by a patent IMA in conjunction with one or more following risk factors: a patent IMA ≥3 mm in diameter, lumbar arteries ≥2 mm in diameter, or an aortoiliac-type aneurysm. The participants were randomly assigned to two groups in a 1:1 ratio: one undergoing EVAR with IMA embolization and the other without. The primary endpoint was T2EL occurrence. The secondary endpoints included aneurysm sac changes and reintervention. In addition to RCT participants, outcomes of patients with low risk of T2EL were also analyzed.

RESULTS

The embolization and non-embolization groups each contained 53 patients. Five-year follow-up after the last patient enrollment revealed that T2ELs occurred in 28.3% and 54.7% of patients in the IMA embolization and non-embolization groups, respectively (P = .006). Both freedom from T2EL-related sac enlargement ≥5 mm and cumulative incidence of sac shrinkage ≥5 mm were significantly higher in the IMA embolization group than in the non-embolization group (95.5% vs 73.6% at 5 years; P = .021; 54.2% vs 33.6% at 5 years; P = .039, respectively). The freedom from T2EL-related sac enlargement ≥10 mm, an alternative indicator for T2EL-related reintervention, showed similar results (100% vs 90.4% at 5 years; P = .019). Outcomes in the low-risk group were preferable than those in the non-embolization group and comparable to those in the IMA embolization group.

CONCLUSIONS

A lower threshold for pre-emptive IMA embolization when implementing EVAR would be more appropriate if limited to patients at high risk of T2ELs.

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.

Role of Aggressive Aneurysm Sac Embolization Before Endovascular Abdominal Aneurysm Repair in Preventing Type II Endoleak and Sac Expansion

Background

This study aimed to evaluate the effect of aggressive embolization of side branches arising from the aneurysmal sac before endovascular aneurysm repair.

Methods

This retrospective study included 95 patients who underwent endovascular infrarenal abdominal aortic aneurysm repair at Tottori University Hospital between October 2016 and January 2021. Of these, 54 underwent standard endovascular aneurysm repair (conventional group), and 41 underwent coiling of the inferior mesenteric and lumbar arteries before undergoing endovascular aneurysm repair (embolization group). The occurrence of type II endoleak, change in aneurysmal sac diameter, and reintervention rate due to type II endoleak during follow-up were evaluated.

Results

Compared to the conventional group, the embolization group had a significantly lower incidence of type II endoleak, more frequent aneurysmal sac shrinkage, and lower aneurysmal sac growth related to type II endoleak.

Conclusion

Our results demonstrated the effectiveness of aggressive aneurysmal sac embolization before endovascular aneurysm repair to prevent type II endoleak and the consequent long-term aneurysmal sac enlargement.

Volumetric analysis of effectiveness of embolization for preventing type II endoleaks following endovascular aortic aneurysm repair

OBJECTIVE

The presence of endoleak was associated with the failure of endovascular aortic aneurysm repair (EVAR) treatment. The key to eliminating type II endoleak has shifted from reintervention to prevention. This study aimed to evaluate the effectiveness and safety of applying fibrin sealant to prevent type II endoleak in conjunction with EVAR.

METHODS

All patients with abdominal aortic aneurysm who underwent EVAR from June 2019 to July 2021 were reviewed. Patients were grouped as Group A: standard EVAR with preemptive embolization and Group B: standard EVAR alone. The primary endpoint was the incidence of type II endoleak. The secondary endpoints were aneurysm sac regression, the inferior mesenteric artery patency, the numbers of patent lumbar arteries, and all-cause mortality.

RESULTS

A total of 104 patients were included in Group A, and 116 were included in Group B. Technical success rate was 100%. The overall incidence of type II endoleak in Group A was significantly lower than that in Group B (4.8% vs 19.0%). The mean time of freedom from type II endoleak was 22.71 months for Group A (95% confidence interval, 21.59-23.83 months) and 19.89 months for Group B (95% confidence interval, 18.08-21.70 months). The Kaplan-Meier estimate of freedom from type II endoleak showed a significantly longer duration of freedom from type II endoleak in Group A (81.0% vs 95.2%). Group A showed a continuous sac regression tendency. In Group B, the sac volume decreased within 12 months but increased by 3.07 cm³ at 24 months. No complications were noted in both groups.

CONCLUSIONS

Nonselective preemptive embolization with porcine fibrin sealant during EVAR was safe and effective in preventing type II endoleak in the short and mid-term. Preemptive embolization can lead to a significantly higher sac regression rate. Larger patient populations and longer follow-ups with randomized control designed trials are expected to verify the long-term effectiveness and safety of preemptive embolization in preventing type II endoleak.

Effectiveness of Inferior Mesenteric Artery Embolization on Type II Endoleak-Related Complications after Endovascular Aortic Repair (EVAR): Systematic Review and Meta-Analysis

Type II endoleak is one of the most common and problematic complications after endovascular aneurysm repair. It has been suggested that the inferior mesenteric artery (IMA) embolization could prevent further adverse events and postoperative complications. This article is a systematic review and meta-analysis following PRISMA guidelines. The Medline, PubMed, Embase, and Cochrane databases were used to identify studies that investigated the effect of IMA embolization on the occurrence of type II endoleaks and secondary interventions in a group of patients with abdominal aortic aneurysm who underwent EVAR compared with results after EVAR procedure without embolization. A random effects meta-analysis was performed. Of 3510 studies, 6 studies involving 659 patients were included. Meta-analysis of all studies showed that the rate of secondary interventions was smaller in patients with IMA embolization (OR, 0.17; SE, 0.45; 95% CI, 0.07 to 0.41; p < 0.01; I2 = 0%). The occurrence of type II endoleaks was also smaller in the embolization group (OR, 0.37; SE, 0.21; 95% CI, 0.25 to 0.57; p < 0.01; I2 = 16.20%). This meta-analysis suggests that IMA embolization correlates with lower rates of type II endoleaks and secondary interventions.

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.

Endovaskuläre Aortenreparatur bei Endoleaks

Sämtliche Patienten nach endovaskulärer Versorgung eines Aortenaneurysmas bedürfen einer regelmäßigen Nachkontrolle, zumeist in jährlichem Abstand. Der kontrastmittelverstärkte Ultraschall und die Computertomographie-Angiographie (CTA) sind die wichtigsten diagnostischen Modalitäten für die Erkennung von Endoleaks. Die (CTA) erlaubt eine bessere Unterscheidung der verschiedenen Endoleak-Typen. Sogenannte Hochdruck-Endoleaks (Typ I und Typ III) stellen, wenn sich nicht kurzzeitig ein Spontanverschluss zeigt, eine absolute Indikation zur Nachbehandlung dar. Typ-II-Endoleaks weisen in der Mehrzahl einen benignen Verlauf auf. Wenn kein Wachstum des Aneurysmasacks erfolgt, kann eine Nachkontrolle im gewohnten Intervall durchgeführt werden. Typ-II-Endoleaks mit assoziiertem Wachstum des Aneurysmasacks können durch Embolisation der verantwortlichen Gefäße behandelt werden. Ob eine Behandlung immer durchgeführt werden muss, ist umstritten. Eine Behandlungsindikation von einem Typ-II-Endoleak mit wachsendem Aneurysmasack ist jedoch gegeben, wenn durch eine Verkürzung des Aneurysmahalses ein sekundäres Typ-I-Endoleak droht. Typ-I-Endoleaks stellen die Hauptlimitation der Stentgraft-Therapie dar. Die beste Prävention eines Typ-I-Endoleaks ist die Bereitstellung einer adäquaten proximalen Landezone. Dies kann durchaus bedeuten, dass fenestrierte Stentgrafts verwendet werden müssen. Die Verwendung von Schrauben oder anderen Fixationsinstrumenten zur sicheren Behandlung auch kurzer Hälse ist derzeit noch in der Studienphase.

Long-term Outcomes after FEVAR for Juxtarenal Aortic Aneurysm

OBJECTIVE

Fenestrated endovascular aortic repair (FEVAR) for juxtarenal aortic aneurysm (jAAA) disease is safe and effective with good short- and mid-term outcomes. Durability issues focus mainly on proximal and distal seal as well as target vessel (TV) instability, and long-term data is scarce. In previous publications we have reported short-term outcomes after FEVAR while comparing early- and late-experience patient groups, as well as long-term results for the early cohort. In this series we provide long-term outcome in the late experience cohort treated with FEVAR in Vascular Center Malmö.

METHODS

Consecutive patients treated in Vascular Center Malmö with FEVAR for jAAA between 2007 and 2011 were included. Data was collected retrospectively from medical- and imaging records. Follow up consisted of a clinical examination 1 month post-operatively, and computed tomography angiography combined with plain abdominal X-ray at 1 and 12 months, and annually thereafter. Primary endpoints were TV instability, reinterventions and survival. Changes in aneurysm diameter and renal function as well as endoleaks were also analyzed.

RESULTS

94 patients were treated. Median follow-up time was 89 (range 0-152) months. 280 fenestrations or scallops were employed of which 205 were stented. Technical success was 89.4%. Primary TV patency was 94% ± 1 % at 1year, 90% ± 2% at 3 years and 89% ± 2% at 5 years. 37 (39.4%) patients needed a total of 70 reinterventions and mean time to first reintervention was 21 ± 3.97 months. 5 (5.3%) patients died of aneurysm related causes and overall survival was 95.7% ± 2.1% at 1 year, 87.1% ± 3.5% at 3 years and 71.0 ± 4.7% at 5 years. A stable or decreasing aortic diameter after treatment was seen in 91% of cases. Mean glomerular filtration rate (GFR) fell from 59.2 ± 14.9 ml/min/1.73m² pre-operatively to 50.0 ± 18.6 ml/min/1.73 m² at end of follow-up.

CONCLUSION

Long-term results after treatment of jAAA with FEVAR remain good and the treatment is safe and effective. Although the need for reintervention remains high, long-term renal function and survival support the use of FEVAR as a valid treatment option for jAAA disease.

Endovascular Aneurysm Repair for Abdominal Aortic Aneurysm: A Comprehensive Review

Abdominal aortic aneurysm (AAA) can be defined as an abnormal, progressive dilatation of the abdominal aorta, carrying a substantial risk for fatal aneurysmal rupture. Endovascular aneurysmal repair (EVAR) for AAA is a minimally invasive endovascular procedure that involves the placement of a bifurcated or tubular stent-graft over the AAA to exclude the aneurysm from arterial circulation. In contrast to open surgical repair, EVAR only requires a stab incision, shorter procedure time, and early recovery. Although EVAR seems to be an attractive solution with many advantages for AAA repair, there are detailed requirements and many important aspects should be understood before the procedure. In this comprehensive review, fundamental information regarding AAA and EVAR is presented.

Laparoscopic Clipping of the Inferior Mesenteric Artery and Intraoperative Indocyanine Green Angiography for Type II Endoleak Following Endovascular Aneurysm Repair

Background: Type II endoleaks from a patent inferior mesenteric artery (IMA) occur in up to one-third of patients undergoing endovascular repair of abdominal aortic aneurysms. In the majority of patients, retrograde flow in the aneurysmal sac outside the endograft will seal over time and is rarely associated with sac enlargement or aortic rupture. Intervention is generally recommended in patients with progressively enlarging endoleaks, especially when the sac diameter increases >10 mm during the follow-up, and endovascular IMA embolization has a high rate of treatment failure. Methods: We report a procedure of laparoscopic IMA clipping combined with intraoperative indocyanine green (ICG) angiography to confirm vascular anatomy, colonic perfusion, and the technical success of the procedure. Results: Three selected octogenarian patients with persistent type II endoleak after endovascular repair of abdominal aortic aneurysm underwent IMA clipping with ICG angiography. Mean operative time was 58 ± 9 minutes. There were no procedure-related complications, and no hypersensitivity reactions nor other side effects associated with ICG dye administration occurred. All patients were discharged home on postoperative day 1 and are asymptomatic and free of recurrence at a mean follow-up of 15 months. Conclusions: Laparoscopic IMA clipping is a safe remedial procedure in patients with type II endoleak after endovascular repair of abdominal aortic aneurysms.

Techniques and future perspectives for the prevention and treatment of endoleaks after endovascular repair of abdominal aortic aneurysms

The presence of endoleaks remains one of the main drawbacks of endovascular repair of abdominal aortic aneurysms leading to the increase of the size of the aneurysmal sac and in most of the cases to repeated interventions. A variety of devices and percutaneous techniques have been developed so far to prevent and treat this phenomenon, including sealing of the aneurysmal sac, endovascular embolisation, and direct sac puncture. The aim of this review is to analyse the indications, the effectiveness, and the future perspectives for the prevention and treatment of endoleaks after endovascular repair of abdominal aortic aneurysms.

Results of Transarterial Embolization for Treating Type 2 Endoleaks: A Single-Center Experience

BACKGROUND

Type 2 endoleaks (T2Es) are the main cause of reintervention after endovascular repair of abdominal aortic aneurysms (EVAR). The objective of this study is to quantify success rates of T2E treatment.

METHODS

This study involves a retrospective analysis of a prospectively maintained database containing data on all consecutive patients treated for a T2E between 2003 and 2017 in a single center. Technical success was defined as absence of endoleak in the final angiographic control after treatment. Clinical success was defined as absence of sac growth over 5 mm in the contrast-enhanced computed tomography performed a year thereafter. Statistics included Kaplan-Meier survival estimates.

RESULTS

A total of 528 elective EVARs were performed in the period. Thirty-six of these (6.8%) developed a T2E requiring reintervention, a median of 37.9 months after EVAR. Twenty-five percent of the treatments were performed more than 5 years after intervention. Twenty-eight of the 36 treatments were performed via transarterial embolization. For this technique, technical success was 71.4% and clinical success was 62.5%. A subsequent reintervention was required in 35.7% of patients. In this cohort, the rate of aneurysm rupture was 10.7% (n = 3/28), open surgical conversion was needed in 2 of 28 cases (7.1%), and rate of aneurysm-related death was 14.3% (n = 4/28) over follow-up.

CONCLUSIONS

A high percentage of patients are at risk of adverse outcomes after T2E treatment. Strict imaging follow-up is still needed in this population.

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.

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.

Type II endoleaks: diagnosis and treatment algorithm

Elective abdominal aortic aneurysm (AAA) repair is recommended for aneurysms greater than 5.5 cm, symptomatic, or rapidly expanding more than 0.5 cm in 6 months. Seventy-five percent of AAAs today are treated with endovascular aneurysm repair (EVAR) rather than open repair. This is fostered by the lower periprocedural mortality, complications, and length of hospital stay associated with EVAR. However, some studies have demonstrated EVAR to result in higher reintervention rates than with open repair, largely due to endoleaks. Type II is the most common, making up 10-25% of all endoleaks. Type II endoleaks, can potentially enlarge and pressurize the aneurysm sac with a risk of rupture. However, many type II endoleaks spontaneously resolve or never lead to sac enlargement. Imaging surveillance and approaches to management of type II endoleaks are reviewed here.