Early Outcomes and Risk Factors Associated with Second Cross-clamping in Mitral Valve Repair: A Propensity-matched Minimally Invasive Cohort Analysis

Background: Second cross-clamping is still required in a subset of patients undergoing mitral valve repair (MVr) due to unsatisfactory initial repair results, even in reference centers. This study investigated risk factors for second cross-clamping (SCC) 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 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 SCC, and Kaplan-Meier survival analysis compared mid-term outcomes.

Results: Out of 1,732 patients, 76 (4.4%) required SCC due to suboptimal repair results. The SCC group had longer cardiopulmonary bypass and aortic cross-clamp times (149.5 versus 99.5 minutes and 96 versus 60 minutes, respectively; p < 0.001). The primary reason for SCC was residual MR. Complex valve pathology in DMR (odds ratio 17.807, p = 0.035) and leaflet restriction in FMR (odds ratio 7.50, p = 0.024) were identified as predictors for SCC. Early postoperative outcomes were similar between groups except for prolonged intensive care unit stay (32 versus 24 hours, p = 0.020). Mid-term survival rates were lower in the SCC group (82.1% versus 87.5% at 5 years, log-rank p = 0.048).

Table 1

	SCC groupn = 76	Control groupn = 76	P-value
CPB time (min)	149.5 (125.25–185.25)	99.5 (78.25–133.5)	<0.001
Cross-clamp time (min)	96 (78.5–118.75)	60 (52–80.5)	<0.001
ICU stay (hours)	32 (24–94)	24 (20–28.75)	0.020
Hospital stay (days)	9 (6–12)	8 (5.25–11)	0.091
30-day mortality, n (%)	4 (5.2)	1 (1.3)	0.172

Conclusion: SCC can be performed safely without unfavorable early postoperative outcomes, though it is associated with impaired mid-term survival estimates. Patients with complex valve pathology in DMR and leaflet restriction in FMR are at higher risk for SCC and may benefit from referral to high-volume centers for optimal results.

Publication History

Article published online:
11 February 2025