Impact of elevated transmitral mean gradient on cardiovascular outcomes after transcatheter mitral valve implantation

Abstract

Background

Transcatheter mitral valve implantation (TMVI) has emerged as an alternative to surgery in high-risk patients with failing mitral bioprosthesis (valve-in-valve) or annuloplasties (valve-in-ring).

Objectives

We aim to evaluate the prognostic impact of an elevated mean gradient > 5 mmHg after the procedure.

Methods

Patients undergoing TMVI from 2010 to 2024 were classified in three groups according to mean gradient after the procedure: Group 1 < 5 mmHg, Group 2 between 5 and 10 mmHg and Group 3 ≥ 10 mmHg.

Results

Among the 175 patients included, indications for TMVI were bioprosthesis failure in 131 patients (74.9%) and ring annuloplasty failure in 44 patients (25.1%), with a median age of 69 (52.5–80) and 155 (88.6%) in NYHA class III or IV. 50 patients were in group 1, 111 in group 2 and 14 in group 3, without any difference in baseline characteristics except for age (P = 0.02) and hemoglobin level (P < 0.001) or procedural findings. At 30 days, the rates of all-cause mortality and rehospitalization for heart failure were similar in the three groups. At a median follow up of 3 years, 43 patients have died (35 for cardiovascular reasons) with a cumulative rate of all-cause mortality at 1 and 2 years of 18.7% and 19.2% respectively. The presence of an elevated mean gradient was not associated with increased risk of mortality (HR 1,11 (0.93–1.31), P = 0.25) but associated with an increase risk of cardiovascular mortality with a HR of 1.22 (1.05–1.42), P = 0.01) and of heart failure (1.15 (1.01–1.31), P = 0.04). At one year, an improvement of NYHA class was observed in the two groups with mean gradient < 10 mmHg (P < 0.01) compared to baseline without any difference for the group 3 (P = 0.33). Median sPAP also significantly improved in groups 1 and 2 (P < 0.01) compared to baseline without improvement in group 3 (P = 1) (Figure 1, Figure 2).

Conclusion

An elevated mean gradient post-TMVI ≥ 10 mmHg was associated with cardiovascular death and hospitalization for heart failure, without significant functional improvement.