Evolution of practice patterns and learning curve of aortic repair using the E-nside off-the-shelf inner branch thoracoabdominal endograft

Objective: To report the impact of the learning curve on the outcomes of branched endovascular aortic repair using an off-the-shelf preloaded inner branch device (E-nside). Methods: Data from a physician-initiated national multicenter registry, including patients treated with E-nside endograft (INBREED [ItaliaN Branch Registry of E-nside EnDograft]) were collected prospectively (2020-2024). End points were early (30-day) technical success, mortality, major adverse events (MAEs), and 2-year freedom from endograft instability and target vessel instability. Patients were divided into early and late cohorts based on the median date of the procedure in each center. Results: There were 215 patients treated with the E-nside, 108 (393 target vessels) in the early and 107 (395 target vessels) in the late cohort. Most patients had a degenerative aneurysm (early, 82%; late, 75%; P = .326) or a chronic dissection (early, 6%; late, 15%; P = .025). Aneurysm extent was thoracoabdominal in 53% of patients and complex abdominal in 47%; and 23% were ruptured or symptomatic and 26% had an aneurysm size of more than 70 mm, without differences between groups. A narrow paravisceral aortic lumen of less than 25 mm was more frequent in the late cohort (late, 30%; early, 18%; P = .037). From the early to the late groups, there was an increase in the use of a total transfemoral approach (late, 29% vs early, 18%; P = .042), balloon-expandable bridging stents (late, 82% vs early, 76%; P = .032), and reinforcement bridging stents (late, 26%; early, 11%; P < .001). Operating time (late, 267 ± 131 minutes; early, 244 ± 130 minutes; P = .230), iodinated contrast volume (late, 181 ± 81 mL; early, 210 ± 141 mL; P = 108; P = .302), and dose area product (late, 272 ± 110 Gycm2 early, 291 ± 118 Gycm2; P = .277) were similar in the two groups. Intraprocedural complications decreased in the later stage of the learning curve (late, 11%; early, 23%; P = .030), whereas overall 30-day mortality (late, 8%; early, 6%; P = .346), technical success (late, 99%; early, 98%; P = .286), and MAEs (late, 27%; early, 29%; P = .879) remained substantially stable. There were no differences in 2-year freedom from endograft instability (late, 100 ± 0%; early, 96 ± 5%; P = 1.00), freedom from target vessel instability (late, 98 ± 3%; early, 94 ± 2%; P = .090), and target vessel primary patency (late, 97 ± 2%; early, 97 ± 2%; P = .321). Conclusions: The increased experience with the E-nside endograft was associated with a more frequent use of a total transfemoral approach and use of balloon-expandable and reinforced bridging stents. From the early to the late stages, there was a significant decrease in intraoperative complications, although most centers were learning independent and achieved a consistent mortality, MAE, procedural metrics, and mid-term results from the start.