Severe Versus Mild–Moderate Pulmonary Hypertension: Outcomes Following Mechanical Mitral Valve Replacement with Posterior Leaflet Preservation

Background: Pulmonary hypertension is common in left-sided heart valve disease, with historical studies reporting mortality rates up to 31% in severe cases undergoing mitral valve surgery. This study evaluates the impact of severe pulmonary hypertension on outcomes of mechanical mitral valve replacement with posterior leaflet preservation by comparing results with patients having mild-to-moderate pulmonary hypertension. Methods: Prospective analysis of 86 patients with mitral valve disease undergoing mechanical valve replacement with posterior leaflet preservation from March 2015 to September 2016 was conducted. Patients were stratified by pulmonary artery pressure: severe (≥60 mmHg, n = 19) versus mild–moderate (35–59 mmHg, n = 67). Primary outcomes included mortality, complications, and functional recovery at 1, 6, and 12 months. Results: The cohort included 67 patients (77.9%) with mild–moderate pulmonary hypertension and 19 patients (22.1%) with severe pulmonary hypertension. Severe pulmonary hypertension patients demonstrated higher NYHA functional class (73.7% class III vs. 46.2%, p = 0.03), larger left atrial diameter (56.3 ± 9.8 vs. 49.5 ± 6.7 mm, p = 0.01), and higher mean pressure gradients (14.4 ± 5.3 vs. 11.3 ± 5.0 mmHg, p = 0.025). Mortality was 5.3% in the severe group versus 0% in the mild–moderate group (p = 0.331). Patients with severe pulmonary hypertension required longer ICU stays (6.3 ± 3.7 vs. 4.7 ± 2.2 days, p = 0.024) but showed no significant differences in ventilation time, reoperation rates, or major complications. At the 12-month follow-up, both groups achieved equivalent outcomes in pulmonary artery pressures, left ventricular function, and cardiac dimensions. Conclusion: In this study with a relatively small sample size, severe pulmonary hypertension was associated with significantly longer intensive care unit stay but not with higher mortality compared to mild–moderate pulmonary hypertension, with both groups attaining comparable functional and hemodynamic parameters at 12 months after mechanical mitral valve replacement with posterior leaflet preservation.