Objectives : Quantification of acute hemodynamic effects of surgical ventricular restoration (SVR).
Background : SVR aims at improving cardiac function by normalization of left ventricular (LV) shape and size. Recent studies indicate that SVR is highly effective with an excellent five-year outcome in patients with ischemic dilated cardiomyopathy. We used pressure-volume analysis to investigate acute changes in systolic and diastolic LV function, mechanical dyssynchrony, and wall stress.
Methods : In three patient groups (total, n=33), pressure-volume loops were measured by conductance catheter before and after surgery. The main study group consisted of 10 patients with ischemic dilated cardiomyopathy (NYHA III/IV, LV ejection fraction <30%) who underwent SVR and CABG. In this group, 7 patients underwent additional restrictive mitral annuloplasty (RMA). To assess potential confounding effects of RMA and cardiopulmonary bypass, we included a group of 10 patients (NYHA III/IV, LV ejection fraction <30%) who underwent isolated RMA and a group of 13 patients with preserved LV function who underwent isolated CABG.
Results : After SVR, end-diastolic and end-systolic volumes were reduced: 211±54 to 169±34mL (p=0.03), and 147±41 to 110±59mL (p=0.04), respectively. LV ejection fraction (27±7 to 37±13%, p=0.04) and end-systolic elastance (1.12±0.71 to 1.57±0.63mmHg/mL, p=0.03) improved. Peak wall stress (358±108 to 244±79 mmHg, p<0.01) and mechanical dyssynchrony (26±4 to 19±6%. p<0.01) were reduced. End-diastolic pressure increased (13±6 to 20±5mmHg, p<0.01), whereas the diastolic chamber stiffness constant tended to be increased (0.021±0.009 to 0.037±0.021mL-1, NS).
Conclusions : SVR achieves normalization of LV volumes and improves systolic function by reducing LV wall stress and mechanical dyssynchrony.