Horizontal Aorta in Transcatheter Self-Expanding Valves: Insights From the HORSE International Multicentre Registry

An increased degree of aortic angulation (AA) represents a challenging feature for bioprosthesis positioning. Whether AA has an impact on procedural outcomes of contemporary self-expanding valves remains unsettled. The aim of this study was to evaluate the impact of AA on procedural outcomes of transcatheter aortic valve replacement with contemporary self-expanding valves.

The HORSE (Horizontal Aorta in Transcatheter Self-Expanding Valves) is an international, retrospective registry including 3862 consecutive patients undergoing transcatheter aortic valve replacement with either Evolut R/PRO (n=1959) or ACURATE neo (n=1903) devices. Patients undergoing Evolut R 34 mm implantation were excluded as no comparable prosthesis size for ACURATE neo is available. AA was evaluated with preprocedural computed tomography, and its impact on device success was evaluated.

In the overall population, AA did not have any impact upon device success, also when adjusting for in-study outcome predictors (odds ratio for 1° increment, 0.99 [95% CI, 0.98–1.01], P=0.306). However, increased AA was associated with lower device success with use of the Evolut R/PRO valves (odds ratio, 0.97 [95% CI, 0.95–0.99]; P=0.004), but not the ACURATE neo valves (odds ratio, 1.00 [95% CI, 0.98–1.03], P=0.304). The best AA cutoff value predicting device success was 49° (47% of the study cohort). Among patients with AA≥49°, Evolut R/PRO valves were associated with lower device success as compared to the ACURATE neo valve (inverse probability weighting odds ratio, 0.62 [95% CI, 0.46–0.83]; P=0.002).

Horizontal aorta, as defined by an AA ≥49°, is a common feature among transcatheter aortic valve replacement candidates and predicts device failure of the Evolut R/PRO valves, but not of the ACURATE neo valve. AA may be an effect modifier of the association between self-expanding valve type and device success.