Minimally Invasive Versus Sternotomy in Redo Mitral Valve Surgery: Short- and Long-Term Outcomes with Meta-Regression and Time-to-Event Analysis.

BACKGROUND

Redo mitral valve surgery carries substantial risk, and the relative benefits of minimally invasive (MI-MVS) versus sternotomy MVS, particularly regarding long-term survival, remain uncertain.

METHODS

Electronic databases were searched for studies comparing MI-MVS with sternotomy MVS in adult redo MVS. Kaplan-Meier curves were digitized to reconstruct individual patient data for time-to-event analysis, with study-level hazard ratios (HR) generated using a Cox frailty model. Perioperative outcomes were pooled using random-effects models. Subgroup analyses evaluated propensity-matched cohorts, endoscopic/video-assisted minithoracotomy, and direct-vision minithoracotomy. Meta-regression explored the impact of study-level covariates on mortality.

RESULTS

Fifteen studies including 3457 patients were analyzed. MI-MVS was associated with lower perioperative mortality compared with sternotomy MVS (odds ratio [OR], 0.33 [95% CI, 0.23-0.48]; P<0.001), reduced incidence of reoperation (OR, 0.65 [95% CI, 0.44-0.98]; P=0.04), and acute kidney injury (OR, 0.58 [95% CI, 0.39-0.87]; P=0.008); rates of stroke and arrhythmia were similar. The direction and magnitude of the mortality effect consistently favored MI-MVS in the subgroup analyses. Time-to-event analysis demonstrated improved survival with MI-MVS (HR, 0.74 [95% CI, 0.62-0.89]; P=0.001), but this was attenuated in the propensity-matched analysis. Meta-regression showed that sex distribution, mean age, and baseline left ventricular ejection fraction did not significantly moderate mortality effects.

CONCLUSIONS

In redo MVS, MI-MVS is associated with improved perioperative outcomes without compromising long-term survival; however, attenuation of the survival difference after propensity matching suggests that this long-term advantage may reflect baseline risk rather than procedural effect.