Abstract 19798: Should Downsizing Still Be the Gold Standard for Treatment of Ischemic Mitral Regurgitation?

Abstract

Background: Mitral valve annuloplasty (MVA) or replacement (MVR) are common strategies in the treatment of functional ischemic mitral regurgitation (FIMR). However, the issue of functional stenosis during exercise in MVA patients was raised. This study aims to compare exercise hemodynamics of MVA and MVR patients. Methods: Thirty patients (23 MVA, 66.8±8.8 y at repair, and 7 MVR, 66.1±5.5y) underwent exercise echocardiography. Stroke volume, ejection fraction, cardiac index, mitral valve gradient, mitral valve area and pulmonary artery pressures were evaluated at rest and at peak exercise. Results: Both patient groups had comparable exercise capacity (65±16 vs 67±15 %predicted; P=0.760). In MVA patients, stroke volume (38±14 to 39±14 mL; P=0.707) and ejection fraction (51±15 to 55±14%; P=0.123) did not change, whereas cardiac index (2.9±1.1 to 4.2±1.2 L/min.m 2 ; P<0.0001), mitral valve gradient (peak 11.8±4.6 to 21.3±7.6 mmHg; mean 5.2±2.2 to 11.3±4.9 mmHg; both P<0.0001) and pulmonary artery pressure (33±10 to 51±16 mmHg; P<0.0001) increased during exercise. In MVR patients, stroke volume (29±7 to 35±7 ml; P=0.006), ejection fraction (52±12 to 61±14%; P=0.009), cardiac index (2.0±0.4 to 3.1±0.9 L/min.m 2 ; P=0.006), mitral valve gradient (peak 9.8±3.8 to 22.0±7.5 mmHg; mean 4.8±1.8 to 12.3±4.3 mmHg; both P<0.05) and pulmonary artery pressure (32±5 to 45±9 mmHg; P=0.006) all increased during exercise. Cardiac index at rest (P=0.040) and at peak exercise (P=0.038) was slightly higher in the MVA group, whereas pulmonary artery pressures at rest (P=0.750) and at peak exercise (P=0.293) were not statistically different. Total pulmonary resistance did not change during exercise (P=0.115 and P=0.546 for MVA and PVR respectively). In MVA, there was a relation between peak mitral valve gradient at rest and pulmonary artery pressure at rest (R=0.525, P=0.017) and at peak exercise (R=0.508; P=0.022). Conclusions: Surgical repair achieves leaflet coaptation at the expense of raised transmitral gradients. Even after successful MVA, patients had worse exercise hemodynamics and lack of mitral valve opening reserve. Therefore we should question downsizing as the gold standard for treatment of FIMR and look for a more patient tailored approach.