Surgical ventricular restoration in patients with ischemic dilated cardiomyopathy: Evaluation of systolic and diastolic ventricular function, wall stress, dyssynchrony, and mechanical efficiency by pressure-volume loops

Objectives: Surgical ventricular restoration aims at improving cardiac function by normalization of left ventricular shape and size. Recent studies indicate that surgical ventricular restoration is highly effective with an excellent 5-year outcome in patients with ischemic dilated cardiomyopathy. We used pressure-volume analysis to investigate acute changes in systolic and diastolic left ventricular function, mechanical dyssynchrony and efficiency, and wall stress. Methods: In 3 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 (New York Heart Association class III/IV, left ventricular ejection fraction <30%) who had surgical ventricular restoration and coronary artery bypass grafting. In this group, 7 patients had additional restrictive mitral annuloplasty. To assess potential confounding effects of restrictive mitral annuloplasty and cardiopulmonary bypass, we included a group of 10 patients (New York Heart Association class III/IV, left ventricular ejection fraction <30%) who had isolated restrictive mitral annuloplasty and a group of 13 patients with preserved left ventricular function who had isolated coronary artery bypass grafting. Results: After surgical ventricular restoration, end-diastolic and end-systolic volumes were reduced from 211 ± 54 to 169 ± 34 mL (P = .03) and from 147 ± 41 to 110 ± 59 mL (P = .04), respectively. Left ventricular ejection fraction (from 27% ± 7% to 37% ± 13%, P = .04) and end-systolic elastance (from 1.12 ± 0.71 to 1.57 ± 0.63 mm Hg/mL, P = .03) improved. Peak wall stress (from 358 ± 108 to 244 ± 79 mm Hg, P < .01) and mechanical dyssynchrony (from 26% ± 4% to 19% ± 6%, P < .01) were reduced, whereas mechanical efficiency improved (from 0.34 ± 13 to 0.49 ± 0.14, P = .03). End-diastolic pressure increased (from 13 ± 6 to 20 ± 5 mm Hg, P < .01), whereas the diastolic chamber stiffness constant tended to be increased (from 0.021 ± 0.009 to 0.037 ± 0.021 mL-1, NS). Conclusions: Surgical ventricular restoration achieves normalization of left ventricular volumes and improves systolic function and mechanical efficiency by reducing left ventricular wall stress and mechanical dyssynchrony. © 2006 The American Association for Thoracic Surgery.