Clinical evaluation of the Hydra self-expanding transcatheter aortic valve: 6 month results from the GENESIS trial.

Objectives: To evaluate the safety and performance of the Hydra transcatheter aortic valve (THV) in the treatment of symptomatic severe aortic stenosis in patients at high or extreme surgical risk.

Background: The Hydra THV (Vascular Innovations Co. Ltd., Nonthaburi, Thailand) is a novel flexible repositionable self-expanding system with supra-annular bovine pericardial leaflets, available in three sizes, covering aortic annuli between 17 and 27 mm.

Methods: The GENESIS trial was a prospective, multi-center, single-arm, 6 month follow-up study conducted in India. The primary performance endpoint was device success defined as per VARC-II criteria at 30 days. The primary safety endpoint was all-cause mortality at 30 days. All endpoints were adjudicated by an independent clinical events committee.

Results: Forty high-risk patients (74.5 ± 6.7 years, 60% men; STS Score:5.6 ± 4.2%) were enrolled in 11 centres. Device success was achieved in 92.5%. The effective orifice area improved from 0.7 ± 0.2 to 2.3 ± 0.6 cm at 30 days and to 2.2 ± 0.7 cm at 6 months (p < .0001). Mean aortic valve gradient decreased from 53.5 ± 18.1 to 8.9 ± 4.9 mmHg at 30 days and to 7.6 ± 2.7 mmHg at 6 months (p < .0001). The rate of new permanent pacemaker implantation was 7.5% at 30 days, and no patient had more than mild paravalvular leak at 6 months. The 30 days and 6 month all-cause mortality was 10.0 and 17.5%, cardiovascular mortality 7.5 and 7.5%, device-related mortality 5.0 and 5.0%, respectively. No patients had stroke up to 6 months.

Conclusions: The GENESIS trial demonstrated high efficacy of the self-expanding Hydra THV. The cardiovascular mortality rate of 7.5% may partly be explained by the inclusion of some centres with no or limited previous experience in transcatheter aortic valve implantation.