Why is the surgical ventricular restoration operation effective for ischemic cardiomyopathy? Geometric analysis with magnetic resonance imaging of changes in regional ventricular function after surgical ventricular restoration

Abstract

Clinical improvement after a surgical ventricular restoration for ischemic cardiomyopathy is increasingly accepted by clinicians, but the mechanism is not completely understood. Ten patients with ischemic cardiomyopathy underwent detailed magnetic resonance imaging for ventricular function before and 6 weeks after surgical ventricular restoration. Surgical procedures included combinations of coronary artery bypass grafting, restrictive mitral annuloplasty, and endoventricular patch plasty. Magnetic resonance imaging analysis included quantification of global and regional systolic function. Anterior and posterior left ventricular regions were divided by an imaginary plane (C-plane) determined from anterior mitral point and both papillary roots. Global stroke volume index increased from 28.8 +/- 4.9 mL/m(2) to 36.5 +/- 8.6 mL/m(2) after surgical ventricular restoration (P = .010) and seemed more related to increased posterior stroke volume index (15.9 +/- 4.3 mL/m(2) preoperatively, 21.8 +/- 3.9 mL/m(2) postoperatively, P = .001) than to changed anterior stroke volume index (15.9 +/- 4.4 mL/m(2) preoperatively, 18.2 +/- 6.9 mL/m(2) postoperatively, P = .369). C-plane area decreased only a little in diastole (37.7 +/- 8.3 cm(2) preoperatively, 32.9 +/- 5.9 cm(2) postoperatively, P = .119) but significantly in systole (31.5 +/- 9.4 cm(2) preoperatively, 23.7 +/- 7.6 cm(2) postoperatively, P = .023). This indicates functional recovery of border zone by restrictive endoventricular patch plasty. Rebuilding geometric normality by surgical ventricular restoration improves contractility of myocardium in border-zone and remote regions, resulting in increased stroke volume index from the posterior left ventricle.