Mitral valve reserve in double-orifice technique: An exercise echocardiographic study

Background and aim of the study: The edge-to-edge technique is used to restore valvular competence in mitral insufficiency. The efficacy of the method is under debate due to the potential for creating functional mitral stenosis. An exercise echocardiographic study was carried out to investigate valve function and hemodynamics in patients who had undergone double-orifice mitral valve repair. Methods: Thirty patients (mean age 49.1 +/- 12.7 years) with previous double-orifice mitral valve repair underwent exercise echocardiography (10 W/min). An annular prosthesis was present in 28 patients (93%). The mean and maximum mitral valve gradient, planimetric valve area, stroke volume, systolic pulmonary artery pressure, heart rate and systolic blood pressure were measured at baseline and at peak stress. Results: At peak stress, heart rate (77.7 +/- 12.2 versus 118.6 +/- 26.0 beats/min, p < 0.00001), systolic blood pressure (124.1 +/- 10.9 versus 146.6 +/- 22.8 mmHg, p < 0.00001) and stroke volume (78.0 +/- 10.2 versus 97.0 +/- 15.1 ml, p <0.00001) were significantly increased, showing a physiological behavior of the mitral valve. The mean mitral valve gradient (2.8 +/- 1.3 versus 4.6 +/- 1.9 mmHg, p < 0.00001), maximum mitral valve gradient (6.4 +/- 2.8 versus 10.5 +/- 4.6 mmHg, p < 0.00002) and systolic pulmonary artery pressure (22.8 +/- 6.1 versus 28.2 +/- 9.9 mmHg, p < 0.001) were increased, but not to pathologic levels. Planimetric valve area increased significantly (3.2 +/- 0.6 versus 4.3 +/- 0.7 cm(2), p <0.00001). A significant negative linear correlation was found between the relative change in mitral valve area and planimetric valve area at rest (r = -0.51, p < 0.05). Conclusion: The double-orifice repair, even with concomitant ring annuloplasty, does not cause mitral valve obstruction, either at baseline or during physical exercise, and does not affect valve hemodynamic and valve reserve.