Left ventricular remodelling early after surgical correction of mitral regurgitation: stroke volume maintenance
Aim. Mitral valve surgery results in the left ventricular (LV) remodelling and adjustment to the new preload and afterload. This study evaluated the dynamics of LV geometry and function immediately after surgical correction of mitral valve (MV) degenerative prolapse. Material and methods. This prospective study included 40 patients: 25 after MV surgery and 15 after coronary artery bypass graft surgery. The latter group served as controls, in order to assess potential impact of cardiopulmonary bypass and cardioplegic arrest on LV function. All participants underwent intraoperative transesophageal echocardiography, before and after cardiopulmonary bypass, after protamine infusion and hemodynamic stabilisation. Simultaneous pulmonary catheterisation ensured that the echocardiographic data were obtained in similar hemodynamic conditions. Results. Immediately after MV surgery, LV fractional area change decreased from 65±7% to 52±% (p<0,001). End-diastolic LV area decreased from 21,3±5,3 to 19,4±4,5 cm <sup>2</sup> (p=0,005), while end-systolic LV area increased from 7,5±2,3 to 9,3±2,5 cm <sup>2</sup> (p<0,001). Stroke volume, measured by the thermodilution method, did not change (54±12% and 57±0%; p=0,5). In the control group, LV fractional area change (54±12% and 57±10%; p=0,19), end-diastolic LV area (16,6±6,2 and 15,7±5,0 cm <sup>2</sup>; p=0,32), and stroke volume (72±29 and 65±19 ml; p=0,15) were similar before and after cardiopulmonary bypass; there was only some reduction in end-systolic LV area (7,9±4,4 and 6,9±3,2 cm <sup>2</sup>; p=0,03). Conclusion. Early after MR surgery, LV fractional area change statistically decreased, primarily due to an increase in end-systolic LV dimensions. It could be one of the compensatory mechanisms to prevent acute increase in stroke volume and subsequent MR after MV surgery.