Risk factors and clinical impact of transvalvular gradient following surgical repair of degenerative mitral regurgitation

Objective

Functional mitral stenosis (FMS) following mitral regurgitation (MR) repair is poorly understood. We aim to assess risk factors of FMS and its clinical impact in patients following the surgical repair of degenerative MR.

Methods

Patients who underwent surgical repair of degenerative MR between January 2016 and March 2023 were included. FMS was considered in patients with a pre-discharge mitral valve gradient ≥5 mmHg. Patients were 1:1 propensity score matched (PSM) by baseline characteristics. Multivariate logistic regression was employed to identify risk factors for developing FMS. Time-to-event data were analysed via the Kaplan-Meier method and multivariate Cox regression. The primary outcomes of our study were mortality and recurrence of MR.

Results

The cohort comprised of 510 patients (FMS n = 99, no-FMS n = 411). Mean clinical follow-up was 51.6 months. The FMS study group demonstrated a lower preoperative ejection fraction than the no-FMS group (53.7 ± 7.4 versus 55.5 ± 7.4, p = 0.04). Multivariate regression reported annuloplasty flexibility (p = 0.001), smaller ring size (p < 0.001), edge-to-edge repair (p = 0.003), and increased cardiopulmonary bypass time (p = 0.03) as risk factors for developing FMS. The PSM cohort (groups n = 99) demonstrated FMS development is associated with recurrence of ≥MR2+ (p = 0.04); however, was not significant following multivariate regression (p = 0.21). A survival benefit trend was observed in the raw no-FMS group (16.2 % versus 10.7 %); however, this did not reach statistical significance (p = 0.22).

Conclusions

This study has identified surgical factors significantly affecting FMS development after degenerative mitral valve repair. FMS was associated with postoperative MR. Further research is required to understand how repair techniques affect postoperative MR and FMS.