Transcatheter edge-to-edge repair (M-TEER) for functional mitral regurgitation (FMR) aims to reduce regurgitation, but this can increase the transmitral mean pressure gradient (TMPG), with a controversial impact on outcomes. A large-scale study from the Japanese OCEAN-Mitral registry has investigated the prognostic significance of balancing residual mitral regurgitation (MR) and TMPG elevation following the procedure.¹

This prospective, multicentre registry analysis included 2,360 patients with FMR who underwent M-TEER. Post-discharge echocardiography was used to categorise patients into five groups based on residual MR severity (≤mild, moderate, or >moderate) and TMPG (<5 mm Hg, ≥5 to <10 mm Hg, or ≥10 mm Hg). The primary endpoint was a composite of all-cause death or heart failure (HF) hospitalisation at two years.

The analysis revealed a progressive increase in the 2-year primary endpoint rate with higher TMPG, rising from 25.0% at a TMPG of 1 mm Hg to 47.0% at 6 mm Hg. In a multivariable analysis, each 1 mm Hg increment in TMPG was independently associated with a higher risk of the primary endpoint (HR: 1.10; 95% CI: 1.02–1.17; P=0.008).

Compared to a reference of ≤mild residual MR, moderate MR was not associated with a significantly higher risk. However, residual MR greater than moderate was a significant predictor of adverse outcomes.

Patients with MR ≤mild and TMPG <5 mm Hg had the lowest incidence of the primary endpoint (28.4%). Notably, the event risk for patients with moderate MR and TMPG <5 mm Hg was not significantly different from this optimal group (HR: 1.13; 95% CI: 0.92–1.41; P=0.24). Factors associated with failing to achieve this optimal haemodynamic result included a larger left atrial volume index, a greater effective regurgitant orifice area, and the use of older-generation G2 devices.

The findings suggest that in patients with FMR, an elevated TMPG after M-TEER is consistently associated with a higher risk of death or HF hospitalisation. A procedural outcome of mild or even moderate residual MR may be acceptable if a low TMPG is maintained, highlighting the importance of a dual-target approach that balances MR reduction with minimising iatrogenic mitral stenosis. This strategy could help refine procedural decision-making and risk stratification for patients undergoing M-TEER.

The authors concluded that prospective studies are needed to confirm these associations and to determine whether this dual-target approach should become a procedural mandate.

This study was funded by Edwards Lifesciences, Medtronic Japan, Boston Scientific, Abbott Medical Japan, and the Daiichi-Sankyo Company.

References

1. Tsunamoto H, Yamamoto M, Kagase A, et al. Using transmitral pressure gradients and residual mitral regurgitation to optimize outcome after transcatheter edge-to-edge repair. JACC. 2025;86(19):1684-1700. https://doi.org/10.1016/j.jacc.2025.07.041.

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