Prophylactic Intraoperative Embolization of Abdominal Aortic Aneurysm Sacs Using N -Butyl Cyanoacrylate/Lipiodol/Ethanol Mixture with Proximal Neck Aortic Balloon Occlusion during Endovascular Abdominal Aortic Repair

Initial Outcomes of Embolization for Type II Endoleak: Comparison of n-Butyl Cyanoacrylate-Ethiodized Oil Mixture with n-Butyl Cyanoacrylate-Ethiodized Oil-Ethanol Mixture

PURPOSE

To compare the safety and effectiveness of n-butyl cyanoacrylate (nBCA)-ethiodized oil (NE) mixture and nBCA-ethiodized oil-ethanol (NEE) mixture embolization for Type II endoleak (T2EL) after endovascular aortic repair.

MATERIALS AND METHODS

This study included 32 patients with 49 procedures who underwent T2EL embolization between January 2008 and June 2022. Cases with no follow-up after embolization, technical failure, treatment with coil only, Type I endoleak at the embolization, and re-embolization were excluded. The resultant final cohort included 24 patients (14 men and 10 women; mean age, 83.3 years [interquartile range, 77-89 years]) who underwent initial T2EL embolization, with 15 patients in the NE group and 9 patients in the NEE group. The 2 groups were compared in terms of adverse events (AEs), freedom from sac enlargement, and freedom from reintervention.

RESULTS

The follow-up period after embolization for T2EL was 960 days (SD ± 1,007) in the NE group and 484 days (SD ± 192) in the NEE group, without significant differences. No AEs above moderate were observed in either group. The rate of freedom from sac enlargement at 1 year was 65.0% in the NE group and 87.5% in the NEE group (P = .03). The rate of freedom from reintervention at 1 year was 69.2% in the NE group and 100.0% in the NEE group (P = .02).

CONCLUSIONS

The NEE group had significantly higher rates of freedom from sac enlargement and reintervention at 1 year compared with the NE group. These results suggest that T2EL embolization with NEE may be more effective than that with NE.

The usefulness of contrast-enhanced subtraction magnetic resonance imaging for detecting endoleaks after endovascular aortic repair with prophylactic intraoperative sac embolization

BACKGROUND

Metallic and hyperdense artifacts and T1-shortening substances in the abdominal aortic aneurysm (AAA) sac generated by embolic materials and lipiodol pose challenges in the identification of endoleaks on follow-up computed tomography (CT) or magnetic resonance imaging (MRI).

PURPOSE

To evaluate the usefulness of contrast-enhanced subtraction MRI (CES-MRI) for detecting endoleaks after endovascular abdominal aortic aneurysm repair (EVAR) with intraoperative AAA sac embolization compared with CE-CT, this study was conducted.

MATERIAL AND METHODS

In this study, 28 consecutive patients who underwent EVAR with prophylactic AAA sac embolization were included. All patients underwent CES-MRI and CE-CT to detect endoleaks. The definitive diagnosis of endoleaks was a consensus reading of CE-CT and CES-MRI by two certified radiologists, in addition to angiography or reproducible radiological findings in the observational examination. Analysis was performed to evaluate which examination was better for detecting endoleaks.

RESULTS

The sensitivity, specificity, and area under the curve of CE-CT and CES-MRI according to observer 1 were 50%, 100%, and 0.813 (95% confidence interval [CI] = 0.625-1.00) and 100%, 95%, and 0.997 (95% CI = 0.984-1.00), respectively, and those according to observer 2 were 50%, 100%, and 0.750 (95% CI = 0.514-0.986) and 100%, 95%, and 0.969 (95% CI = 0.903-1.00), respectively. Intolerable artifacts were significantly observed on CE-CT. The severity of the artifacts did not depend on the stent graft on CT and MRI.

CONCLUSION

Although no significant difference was observed, CES-MRI tended to have better accuracy for endoleak detection in EVAR with intraoperative AAA sac embolization than CE-CT.

Selective aneurysmal sac neck-targeted embolization during endovascular repair of abdominal aortic aneurysm with hostile neck anatomy

PURPOSE

To evaluate the efficacy and safety of selective aneurysmal sac neck-targeted embolization in endovascular aneurysm repair (EVAR) in patients with a hostile neck anatomy (HNA).

MATERIALS AND METHODS

Between October 2020 and June 2022, patients with an abdominal aortic aneurysm (AAA) and HNA who underwent EVAR with a low-profile stent graft and a selective aneurysmal sac neck-targeted embolization technique were analysed. An HNA was defined by the presence of any of the following parameters: infrarenal neck angulation > 60°; neck length < 15 mm; conical neck; circumferential calcification ≥ 50%; or thrombus ≥ 50%. Before occluding the entire aneurysm during the procedure, a buddy wire was loaded prophylactically into the sac through the contralateral limb side. If a type Ia endoleak (ELIa) occurred and persisted despite adjunctive treatment such as balloon moulding or cuff extension, this preloaded wire could be utilized to enable a catheter to reach the space between the stent graft and sac neck to perform coil embolization. In the absence of ELIa, the wire was simply retracted. The primary outcome of this study was freedom from sac expansion and endoleak-related reintervention during the follow-up period; secondary outcomes included technical success and intraoperative and in-hospital postoperative complications.

RESULTS

Among the 28 patients with a hostile neck morphology, 11 (39.5%) who presented with ELIa underwent intraprocedural treatment involving sac neck-targeted detachable coil embolization. Seventeen individuals (60.7%) of the total patient population did not undergo coiling. All patients in the coiling group underwent balloon moulding, and 2 patients additionally underwent cuff extension. In the noncoiling group, 14 individuals underwent balloon moulding as a treatment for ELIa, while 3 patients did not exhibit ELIa during the procedure. The coiling group showed longer operating durations (81.27 ± 11.61 vs. 70.71 ± 7.17 min, P < 0.01) and greater contrast utilization than the noncoiling group (177.45 ± 52.41 vs. 108.24 ± 17.49 ml, P < 0.01). In the entire cohort, the technical success rate was 100%, and there were no procedure-related complications. At a mean follow-up of 18.6 ± 5.2 months (range 12-31), there were no cases of sac expansion (19 cases of sac regression, 67.86%; 9 cases of stability, 32.14%) or endoleak-related reintervention.

CONCLUSIONS

Selective aneurysmal sac neck-targeted embolization for the treatment of ELIa in AAA patients with an HNA undergoing EVAR is safe and may prevent type Ia endoleak and related sac expansion after EVAR.

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.

Prophylactic Aneurysm Embolization during EVAR Is Safe, Improves Sac Regression and Decreases the Incidence of Type II Endoleak

BACKGROUND

Clinically significant endoleaks remain costly, time-consuming, morbid and even mortal following endovascular aneurysm repair (EVAR). Perigraft arterial sac embolization (PASE) has been utilized to treat type II endoleaks (T2EL) diagnosed at the time of EVAR or after repair. Our objective was to analyze the safety and efficacy of prophylactic PASE on the incidence of T2EL and aneurysm sac regression in patients undergoing EVAR.

METHODS

We performed a retrospective review of prospectively maintained databases from the University of California San Diego and the San Diego Veterans Affairs hospitals between 2015 and 2019. Prophylactic PASE (pPASE) was performed at the time of EVAR with thrombin, contrast and gelfoam liquid embolic aneurysm treatment as previously described. We evaluated technical success, freedom from T2EL, freedom from reintervention, from sac expansion, from type I/III EL, from all-cause mortality (ACM), from aneurysm-related mortality and from non-target embolization (NTE).

RESULTS

A total of 44 patients were included in the study. Technical success was 100% and no NTE was observed. The average duration of follow-up was 14 ± 11months. In those treated and followed by CT scan, 100% of patients' aneurysms halted their growth following PASE, while 65.9% demonstrated sac regression. Mean aneurysm sac diameter decreased by 9 mm (95% CI 7-12). At 3 years, freedom from T2EL was 87.1%. Presence of T2EL did not result in aneurysm expansion during the follow-up period and thus did not require reintervention in any of these patients. Freedom from re-intervention was 83.2% for Type Ib EL and limb occlusion and all procedures were determined to be successful at the time of completion. No aneurysm-related deaths occurred during the follow-up.

CONCLUSIONS

PASE proves to be an effective tool in sac management for prophylaxis of endoleak and maximizing sac regression in EVAR. It is safe, effective and durable when employed in this manner in the short and medium-term and was associated with low rates of T2ELs and reinterventions and a 100% freedom from sac expansion. Further analysis is required to evaluate the long-term outcomes of this adjunctive procedure in EVAR.

Feasibility and Safety of n-Butyl Cyanoacrylate-Lipiodol-Iopamidol as an Alternative Liquid Embolic Material

PURPOSE

To evaluate the feasibility and safety of n-butyl cyanoacrylate (NBCA)-Lipiodol-Iopamidol (NLI) as a liquid embolic material.

MATERIALS AND METHODS

In vitro, the ratio of NLI components was adjusted and the configuration of the mixtures was assessed visually in saline. In vivo, 14 wide-necked aneurysms were created on the common carotid and external iliac arteries of four female swine. Under balloon occlusion, 12 aneurysms were embolized with NLI prepared at a NBCA-Lipidol-Iopamidol ratio of 2:3:1 (NLI231), and two were embolized with NBCA-Lipiodol (NL) prepared at a NBCA-Lipiodol ratio of 1:2 (NL12) as a trial group. We performed angiography to evaluate the effectiveness of embolization and adhesion of the embolic material to the balloons or microcatheters.

RESULTS

In vitro, NLI231 (33% NBCA) was considered to be the optimal ratio for aneurysm embolization based on its configuration and stability. In vivo, embolization using NLI231 was successful and no adhesion between the embolic material and the balloons or microcatheters was observed in all 12 aneurysms. Embolization with NL12 was impossible in the other two aneurysms due to leakage and adhesion of NL.

CONCLUSION

The configuration of NLI changed at each ratio. NLI231 is a feasible and safe liquid embolic material for balloon-assisted embolization of wide-necked aneurysms in swine.

A Novel Technique for the Treatment of Type 2 Endoleak After Endovascular Aortic Repair: Sac Embolization with Balloon Occlusion of the Aorta (SEBOA)

PURPOSE

We presented a new method of sac embolization using n-butyl-cyanoacrylate (NBCA) with balloon occlusion of the aorta (SEBOA) that can facilitate decreasing flow rate of the involved branches with the goal of type 2 endoleak resolution after endovascular aortic repair (EVAR).

TECHNIQUE

This technique is demonstrated in six patients who required type 2 endoleak treatment including previous technical failure. A transarterial approach was performed in four patients and transabdominal direct puncture in two. Technical success was defined as complete embolization of both involved branches and sac on postoperative CT. Sacography under balloon occlusion of the aorta demonstrated decreased flow rate of the all involved branches in all patients. SEBOA was performed using 25 or 33% of NBCA diluted with lipiodol. Technical success was obtained in 3 of 6 patients, and one major complication was observed with adhesion of NBCA to the microcatheter resulting in foreign body retention.

CONCLUSION

SEBOA may help solve the difficulty of type 2 endoleak treatment after EVAR as decreased flow rate of the involved branches under balloon occlusion of the aorta was achieved in all patients. However, protocols regarding concentration of NBCA or using other embolic materials are needed to improve the success rate.

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

Background

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

Methods

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

Results

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

Conclusions

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