Left ventricular remodeling early after correction of mitral regurgitation: Maintenance of stroke volume with decreased systolic indexes

Objective

Mitral valve repair for mitral regurgitation is followed by left ventricle adjustment to new preload and afterload. We evaluated left ventricular geometry and function immediately after mitral valve repair for degenerative prolapse.

Methods

We prospectively studied 25 patients undergoing mitral valve repair; 15 patients undergoing a coronary artery bypass graft served as controls to determine the impact of cardiopulmonary bypass and cardioplegic arrest on left ventricular function. Intraoperative transesophageal echocardiography was conducted after sternotomy before initiation of cardiopulmonary bypass and after termination of cardiopulmonary bypass and protamine infusion. Simultaneous pulmonary catheter data ensured that the images were obtained under similar hemodynamic conditions.

Results

Immediately after mitral valve repair, left ventricular fractional area change decreased significantly from 65% ± 7% to 52% ± 8% (P < .001). Left ventricular end-diastolic area decreased minimally (21.3 ± 5.3 cm² vs 19.4 ± 4.5 cm²; P = .005), whereas left ventricular end-systolic area increased significantly (7.5 ± 2.3 cm² vs 9.3 ± 2.5 cm²; P < .001). Notably, forward stroke volume (thermodilution) remained similar (63 ± 24 mL vs 66 ± 19 mL; P = .5). No significant difference was found in controls between pre- cardiopulmonary bypass and post-cardiopulmonary bypass fractional area change (54% ± 12% vs 57% ± 10%; P = .19), left ventricular end-diastolic area (16.6 ± 6.2 cm² vs 15.7 ± 5.0 cm²; P = .32), and stroke volume (72 ± 29 mL vs 65 ± 19 mL; P = .15); they had a slight decrease in left ventricular end-systolic area (7.9 ± 4.4 cm² vs 6.9 ± 3.2 cm²; P = .03).

Conclusions

Early after correction of mitral regurgitation, left ventricular fractional area change decreases significantly, primarily as the result of a larger end-systolic dimension. This may be a compensatory mechanism to prevent augmentation of forward stroke volume after mitral valve repair.

CTSNet classification: 17, 35

Abbreviations and Acronyms: CABG, coronary artery bypass grafting, CPB, cardiopulmonary bypass, EF, ejection fraction, FAC, fractional area change, FS, fractional shortening, LV, left ventricle, left ventricular, LVEDA, left ventricular end-diastolic area, LVEDD, left ventricular end-diastolic dimensions, LVEF, left ventricular ejection fraction, LVESA, left ventricular end-systolic area, LVESD, left ventricular end-systolic dimensions, MR, mitral regurgitation, MV, mitral valve, TEE, transesophageal echocardiography, TTE, transthoracic echocardiography