Mid-term outcomes and hemodynamic performance of transcatheter aortic valve implantation in bicuspid aortic valve stenosis: Insights from the bicuSpid TAvi duraBILITY (STABILITY) registry

Background: Limited data are available on transcatheter heart valves (THVs) durability in bicuspid aortic valve (BAV) stenosis. Aims: To evaluate evaluating 4-year clinical and echocardiographic outcomes of patients with BAV undergoing transcatheter aortic valve implantation (TAVI). Methods: The bicuSpid TAvi duraBILITY (STABILITY) registry is an Italian multicentre registry including all consecutive patients with BAV and severe aortic stenosis (AS), treated by means of TAVI between January 2011 and December 2017. Outcomes of interest were all-cause death at 4-year, over time changes in echocardiographic measurements, and THV durability according to the valve aortic research consortium (VARC)-3 update definitions. Results: Study population included 109 patients (50% females; mean age 78 ± 7.5 years) with a mean Society of Thoracic Surgeons Predicted Risk of Mortality score of 5.1 ± 4.3%. Median follow-up (FU) duration was 4.1 years [interquartile range: 2.8–5.1]. The overall cumulative incidence of all-cause death by Kaplan–Meier estimates at 4 years was 32%. Compared to baseline, a significant decrease in transprosthetic mean gradient was obtained after TAVI (54 ± 16 vs. 10 ± 5 mmHg; p < 0.001), whereas a significant increase was observed at 4-year (13 ± 6.4 mmHg, p = 0.03). Cumulative incidence of hemodynamic valve dysfunction (HVD) was 4%. Six patients met HVD criteria: three moderate and three severe HVD. All three cases of severe HVD were clinically relevant (bioprosthetic valve failure [BVF]) with two patients receiving a reintervention (TAVI in TAVI), and one patient experiencing a valve-related death due to endocarditis. Conclusions: The STABILITY registry suggests that in patients with severe AS and BAV undergoing TAVI, postprocedural clinical benefits might last, over time, up to 4-year FU. The low rates of severe HVD and BVF may support the hypothesis of good THV durability also in BAV recipient.