Prosthesis–patient mismatch after mitral valve replacement: A pooled meta-analysis of Kaplan–Meier-derived individual patient data

Objective: The hemodynamic effect and early and late survival impact of prosthesis–patient mismatch (PPM) after mitral valve replacement remains insufficiently explored. Methods: Pubmed, Embase, Web of Science, and Cochrane Library databases were searched for English language original publications. The search yielded 791 potentially relevant studies. The final review and analysis included 19 studies compromising 11,675 patients. Results: Prosthetic effective orifice area was calculated with the continuity equation method in 7 (37%), pressure half-time method in 2 (10%), and partially or fully obtained from referenced values in 10 (53%) studies. Risk factors for PPM included gender (male), diabetes mellitus, chronic renal disease, and the use of bioprostheses. When pooling unadjusted data, PPM was associated with higher perioperative (odds ratio [OR]: 1.66; 95% confidence interval [CI]: 1.32–2.10; p <.001) and late mortality (hazard ratio [HR]: 1.46; 95% CI: 1.21–1.77; p <.001). Moreover, PPM was associated with higher late mortality when Cox proportional-hazards regression (HR: 1.97; 95% CI: 1.57–2.47; p <.001) and propensity score (HR: 1.99; 95% CI: 1.34–2.95; p <.001) adjusted data were pooled. Contrarily, moderate (HR: 1.01; 95% CI: 0.84–1.22; p =.88) or severe (HR: 1.19; 95% CI: 0.89–1.58; p =.24) PPM were not related to higher late mortality when adjusted data were pooled individually. PPM was associated with higher systolic pulmonary pressures (mean difference: 7.88 mmHg; 95% CI: 4.72–11.05; p <.001) and less pulmonary hypertension regression (OR: 5.78; 95% CI: 3.33–10.05; p <.001) late after surgery. Conclusions: Mitral valve PPM is associated with higher postoperative pulmonary artery pressure and might impair perioperative and overall survival. The relation should be further assessed in properly designed studies.