Sealing Devices in Chimney Aortic Repair (CH EVAS) Versus Chimney Aortic Repair with Conventional Devices (CH EVAR): A Systematic Review

What we have learned from in-vitro studies of the chimney endovascular technique for treatment of complex abdominal aortic aneurysms: A systematic review

BACKGROUND

A considerable number of patients with abdominal aortic aneurysms (AAA) is not eligible for standard endovascular repair. These complex cases require alternative surgical approaches including the readily available chimney graft endovascular aneurysm repair (Ch-EVAR) or sealing (Ch-EVAS). The optimal configuration for Ch-EVAR or Ch-EVAS is important for success but not yet known.

OBJECTIVE

The aim of the present study was to analyze current data of the outcomes of in-vitro chimney graft treatment in complex AAA.

METHODS

A systematic review following PRISMA guidelines was conducted including studies reporting on gutter size, main graft compression, and chimney graft compression in in-vitro configurations.

RESULTS

The search resulted in 285 articles. 11 studies considering 219 individual tests could be included. Gutter size was comparable between Ch-EVAR and Ch-EVAS configurations. In Ch-EVAR set-ups, the deployed BECG were Advanta V12, VIABAHN®, and BeGraft. One type of SECG was used: VIABAHN®. The four types of main grafts (MG) deployed were: Endurant™ I/II; EXCLUDER Conformable AAA Endoprosthesis and AAA Endoprosthesis, and AFX™ Endovascular AAA Delivery System. In the EVAS-configurations, the Nellix® EVAS system was deployed. In general, SECG presented smaller gutters with higher chimney graft compression. 30% main grafts oversizing seems to give the smallest gutters without high risk of infolding of MG. Oversizing, EndoAnchors, and secondary endobag filling (in Ch-EVAS) reduced gutter sizes. CG ballooning during the entire polymer injection in Ch-EVAS prevented CG compression.

CONCLUSION

In-vitro investigations provide insight in optimal Ch-EVAR and Ch-EVAS configurations for simulated complex AAA repair. The findings above might aid physicians in their planning to potential CG set-ups and can be used in future research to refine the most optimal configuration for chimney graft technique in complex AAA.

Single-Center Preliminary Experience with Gutter-Plugging Chimney Stent-Graft for Aortic Dissection

PURPOSE

To report the early 2-year results and experience of a novel gutter-plugging chimney stent-graft in a single center that participated in the clinical trial of Prospective Study for Aortic Arch Therapy with stENt-graft for Chimney technology.

MATERIALS AND METHODS

Patients diagnosed with aortic dissection were treated with the novel chimney stent-grafts named Longuette™ for the left subclavian artery revascularization. Primary study outcomes were the incidence of freedom from major adverse events within 30 days and success rate of the operation over 12 months.

RESULTS

A total of 34 patients were enrolled between September 2019 and December 2020. The immediate technical success rate (stent-grafts successfully deployed without fast-flow type Ia or type III endoleak intraoperatively) was 100%, and there were no conversions to open repair. Type Ia and type II endoleaks were noted in three patients (8.8%) and one patient (2.9%) at discharge, respectively. One patient (2.9%) with type Ia endoleak underwent coil embolization at 12 months because of false lumen dilation, and one (2.9%) case of type Ia endoleak resolved spontaneously at 24 months. One chimney stent (2.9%) was revealed with stenosis at discharge and occluded with thrombosis at 6 months postoperatively. During the 2-year follow-up, there was no death, rupture, stroke, paraplegia, left arm ischemia, retrograde dissection, stent-graft induced new entry, or stent migration.

CONCLUSION

The initial results of the Longuette™ stent-graft for revascularization of the left subclavian artery are encouraging with a high technical success rate. Further multicenter follow-up outcomes are required to assess the long-term durability.

LEVEL OF EVIDENCE

Level 4, Case Series.

Impact of renal chimney intra-aortic stent length on branch and end-stent angle in chimney endovascular aneurysm repair and endovascular aneurysm sealing configurations

OBJECTIVE

Practice patterns and durability of parallel stent graft techniques in complex endovascular aneurysm repair (EVAR) remain poorly defined. We aimed to quantify and compare the impact of renal chimney intra-aortic stent length (IASL) on geometric deformations of renal arteries in complex EVAR.

METHODS

Thirty-eight nonconsecutive patients underwent EVAR utilizing parallel stent graft techniques (chimney EVAR [chEVAR], n = 28; chimney endovascular aneurysm sealing [chEVAS], n = 10) between 2010 and 2016. A total of 59 renal chimney stent grafts were used. Geometric quantification was derived from three-dimensional model-based centerline extraction. Renal chimney intra-aortic stent length (IASL) was defined as the length of chimney stent that extended from the proximal edge of the chimney stent to the ostium of the corresponding renal artery.

RESULTS

Mean IASL for both left and right renal arteries in the cohort was 35.7 mm. Renal arteries containing chimney IASL <30 mm trended toward a greater branch angle (135.4 vs. 127.8°, p = .06). Left renal arteries showed significantly greater branch angle among those with IASL <40 mm (135.5 vs. 121.7°, p = .045). Mean IASL for renal arteries in chEVAR was significantly longer compared to chEVAS (39.2 vs. 26.3 mm, p = .003). No difference was noted in overall branch angle or end-stent angle based on procedure type. ChEVAR with IASL <30 mm had significantly greater end-stent angle (48.2 vs. 33.5°, p = .03). In contrast, chEVAS patients showed no difference in end-stent angle based on IASL thresholds, but did have significantly greater branch angle among those with IASL <30 mm when grouped by both all renal arteries (133.5 vs. 113.5°, p = .004) and right renal arteries (134.3 vs. 111.6°, p = .02).

CONCLUSIONS

Renal chimney stents with longer IASL appear to exhibit less renal artery deformation, suggesting a more gradual and perpendicular transition of the chimney stent across the renal ostium.

Retrograde Branched Endovascular Repair as a Feasible Option to Treat Complex Aortic Aneurysm Using the Retrograde Branched Extension Limb Assembling Technique

PURPOSE

To present the primary experiences in treating suprarenal aneurysms, juxtarenal aneurysms, thoracoabdominal aortic aneurysms, and aneurysms after dissection with hostile anatomical features using the retrograde branched extension limb assembling (REBEL) technique.

MATERIALS AND METHODS

The study included 23 consecutive patients undergoing total endovascular repair with the REBEL technique from August 2014 to January 2019. Twelve patients had abdominal aortic aneurysms (4 juxtarenal, 8 suprarenal), 6 had thoracoabdominal aortic aneurysms (type IV), and 5 had postdissection aneurysms. The patients were unsuitable for treatment with current off-the-shelf devices or required emergent repair. The evaluated outcomes were technical success, operative mortality, complication morbidity, late survival, endoleakage, and reintervention during follow-up.

RESULTS

Technical success rate was 100%. In total, 60 visceral vessels were targeted (38 renal arteries, 1 accessory renal artery, 14 superior arteries, and 7 celiac arteries). The mean follow-up period was 20.1 ± 15.1 months (range 2-56), and no aneurysm-related mortality occurred during follow-up. No occlusion of target vessels occurred. Two type II endoleaks and 1 stent migration occurred in 3 (13.0%) patients, and reinterventions were successfully performed. One patient (4.3%) died of myocardial infarction at 38 months.

CONCLUSIONS

The REBEL technique is a feasible option with acceptable results for complex aortic aneurysms. Long-term follow-up of a large sample size is needed to determine the efficacy and durability of this novel technique.