One-Year Outcomes of Transseptal Mitral Valve-in-Valve in Intermediate Surgical Risk Patients.

Background: Transcatheter mitral valve-in-valve replacement offers a less-invasive alternative for high-risk patients with bioprosthetic valve failure. Limited experience exists in intermediate-risk patients. We aim to evaluate 1-year outcomes of the PARTNER 3 mitral valve-in-valve study.

Methods: This prospective, single-arm, multicenter study enrolled symptomatic patients with a failing mitral bioprosthesis demonstrating greater than or equal to moderate stenosis and regurgitation and Society of Thoracic Surgeons score ≥3% and <8%. A balloon-expandable transcatheter heart valve (SAPIEN 3, Edwards Lifesciences) was used via a transeptal approach. The primary end point was the composite of all-cause mortality and stroke at 1 year.

Results: A total of 50 patients from 12 sites underwent mitral valve-in-valve from 2018 to 2021. The mean age was 70.1±9.7 years, mean Society of Thoracic Surgeons score was 4.1%±1.6%, and 54% were female. There were no primary end point events (mortality or stroke) through 1 year, and no left-ventricular outflow tract obstruction, endocarditis, or mitral valve reintervention was reported. Six patients (12%) required rehospitalization, including heart failure (n=2), minor procedural side effects (n=2), and valve thrombosis (n=2; both resolved with anticoagulation). An additional valve thrombosis was associated with no significant clinical sequelae. From baseline to 1 year, all subjects with available data had none/trace or mild (grade 1+) mitral regurgitation and the New York Heart Association class improved in 87.2% (41/47) of patients.

Conclusions: Mitral valve-in-valve with a balloon-expandable valve via transseptal approach in intermediate-risk patients was associated with improved symptoms and quality of life, adequate transcatheter valve performance, and no mortality or stroke at 1-year follow-up.

Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03193801.