IMMEDIATE AND LONG-TERM OUTCOMES AFTER BIOPROSTHETIC MITRAL VALVE REPLACEMENT WITH THE PRESERVATION OF THE SUBVALVULAR APPARATUS
Aim. To assess the immediate and long-term outcomes after bioprosthetic mitral valve replacement with the preservation of the subvalvular apparatus. Methods. 304 patients who underwent primary bioprosthetic mitral valve replacement in the period from 2001 to 2009 were included in the study. Patients were enrolled into two groups with either preserved subvalvular structures (Group 1. n = 142, 47%) or resected structures (Group 2, n = 162) during bioprosthetic mitral valve replacement. For the unbiased assessment of the efficiency of valve-preserving approach, randomly selected patients from Group 1 (n = 75) and Group 2 (n = 40) underwent preoperative and postoperative invasive monitoring of the central hemodynamics using the Swan-Ganz thermodilution catheter. Results. In-hospital mortality was 1.4% (n = 2) in Group 1 and 4.3% in Group 2. The most common cause of death was acute left ventricular failure. We found that the preservation of subvalvular structures allows ensuring the optimal linear and volumetric echocardiography parameters in the immediate postoperative period, despite the hemodynamic profile of the defect. However, the positive effects were more pronounced in patients with more severe mitral regurgitation. Patients with preserved subvalvular structures had more durable surgical mitral valve replacement according to the echocardiographic findings in the long-term period. The invasive monitoring of central hemodynamics allowed determining that total subvalvular apparatus preservation was associated with more significant pressure decline in the pulmonary circulation (mean pulmonary arterial pressure and pulmonary capillary wedge pressure) and improved cardiac index and output. Posterior leaflet preservation was associated with less pronounced changes and patients who underwent routine mitral valve replacement had the worst intermediate outcomes. Conclusion. The results of the presented study suggest that the preservation of subvalvular apparatus, unless otherwise indicated, is associated with improved immediate and long-term outcomes after mitral valve replacement.