Using Transmitral Pressure Gradients and Residual Mitral Regurgitation to Optimize Outcome After Transcatheter Edge-to-Edge Repair

Abstract

Background: Although reducing mitral regurgitation (MR) after mitral transcatheter edge-to-edge repair (M-TEER) improves outcomes, the impact of increased transmitral mean pressure gradient (TMPG) remains controversial.

Objectives: This study aimed to evaluate the clinical significance of MR reduction and TMPG elevation in patients with functional mitral regurgitation (FMR) after M-TEER.

Methods: A total of 2,360 FMR patients were evaluated using postdischarge echocardiography after M-TEER. The relationship between TMPG and outcomes was assessed using spline analysis and group-based comparisons. Based on residual MR severity and TMPG, patients were categorized into 5 groups to assess the prognostic impact of postprocedural hemodynamics: MR ≤ mild and TMPG <5 mm Hg (n = 1,702), MR ≤ mild and TMPG ≥5 to <10 mm Hg (n = 164), moderate MR and TMPG <5 mm Hg (n = 361), moderate MR and TMPG ≥5 to <10 mm Hg (n = 71), and MR > moderate or TMPG 10 mm Hg (n = 62). The primary endpoint was all-cause death or heart failure hospitalization.

Results: The 2-year primary endpoint event rates increased progressively with higher TMPG, from 25.0% at 1 mm Hg to 47.0% at 6 mm Hg. In multivariable analysis, TMPG per 1 mm Hg increment was independently associated with the primary endpoint (HR: 1.10; 95% CI: 1.02-1.17; P = 0.008). Using MR ≤ mild as the reference, moderate MR was not linked to higher risk, whereas MR > moderate remained a significant predictor of primary endpoint. The patients with MR ≤ mild and TMPG <5 mm Hg had the lowest incidence of the primary endpoint among the 5 groups (28.4%, 39.0%, 33.0%, 43.7%, 48.4%; P < 0.001). However, event risk was not significantly different between patients with moderate MR and TMPG <5 mm Hg and those with MR ≤ mild and TMPG <5 mm Hg (HR: 1.13; 95% CI: 0.92-1.41; P = 0.24). Failure to achieve MR ≤ mild and TMPG <5 mm Hg was associated with larger left atrial volume index, greater effective regurgitation orifice area, elevated baseline TMPG, and old-generation G2 device use.

Conclusions: In patients with FMR, elevated TMPG was consistently associated with higher risks of the primary endpoint. Mild or moderate residual MR with low TMPG was associated with more favorable prognosis, suggesting that balancing MR reduction and TMPG may help refine risk stratification after M-TEER. (Japanese Registry study of valvular heart diseases treatment and prognosis; UMIN000023653).

Keywords: functional mitral regurgitation; mitral valve transcatheter edge-to-edge repair; residual mitral regurgitation; transmitral mean pressure gradient.