Early outcomes and risk factors associated with second cross-clamping in mitral valve repair: A propensity-matched minimally invasive cohort analysis

OBJECTIVES Second cross-clamping (2nd XCL) is infrequently required in patients undergoing mitral valve repair (MVr), mostly due to unsatisfactory initial repair results. This study investigated risk factors for 2nd XCL and compared early and mid-term outcomes in a propensity-matched cohort undergoing minimally invasive MVr (MI-MVr). METHODS A retrospective review of patients undergoing MI-MVr for degenerative mitral regurgitation (DMR) or functional mitral regurgitation (FMR) between October 2014 and March 2024 was performed. Patients with a single versus 2nd XCL were matched 1:1 based on age, gender, MR etiology, and other baseline characteristics. Echocardiographic assessments, surgical techniques, and postoperative outcomes were analyzed. Logistic regression identified predictors for 2nd XCL, and Kaplan–Meier survival analysis compared mid-term outcomes. RESULTS Out of 1,732 patients, 76 (4.4%) required 2nd XCL. The primary reason for 2nd XCL was residual MR. Complex valve pathology in DMR (odds ratio 3.386, p = 0.005) and leaflet restriction in FMR (odds ratio 8.00, p = 0.014) were identified as predictors for 2nd XCL, but were not confirmed as independent predictors in multivariable regression analysis. The 2nd XCL group had longer cardiopulmonary bypass and aortic cross-clamp times (149.5 vs 99.5 min and 96.0 vs 60.0 min, respectively; p < 0.001). No differences were observed in midterm outcomes between the 2nd XCL and control groups (74.4% vs 84.6%, log-rank p = 0.07), except for prolonged length of ventilation time and intensive care unit stay (17.0 vs 12.5 hours and 32.0 vs 24.0 hours, p < 0.001, respectively). CONCLUSIONS 2nd XCL can be performed safely without impairing early and mid-term postoperative outcomes. Patients with complex valve pathology in DMR and leaflet restriction in FMR are at a higher risk for 2nd XCL.