Lessons from a mathematical hypothesis — modification of the endoventricular circular patch plasty

Abstract

Surgical ventricular restoration has been the bailout therapy for end-stage heart failure due to ischemic cardiomyopathy in patients not suitable for cardiac transplantation. The recently concluded STICH trial has stated that surgical restoration of the left ventricle does not benefit this subgroup of patients clinically as compared with revascularization alone. The reasons for failure of this trial are multifactorial. The technique of surgical ventricular restoration employed in the STICH trial was circular endoventricular patch plasty. The various drawbacks related to this technique can be offset by a modification based on a mathematical hypothesis, which should result in a more physiological ventricular geometry, with consequent late reverse remodeling and improved left-ventricular performance. A total of 54 consecutive patients out of 102 patients with post-infarction left-ventricular aneurysms were studied before and 2 years after surgical ventricular restoration by linear endoventricular patch plasty using two-dimensional (2D) echocardiography and contrast ventriculography. Linear endoventricular patch plasty resulted in a decrease in end-diastolic volume (EDV) of 40.2 ml (95% confidence interval (CI): 33.6, 46.7) and stroke volume (SV) of 10.0 ml (95% CI: 6.6, 13.5) and increase in ejection fraction (EF) of 6.7% (95% CI: 5.5, 7.9). There was a further 14% decrease in EDV and SV (30%) at 2 years with increase in EF (20%). There was a persistent significant improvement in sphericity index. The changes in EDV and SV were linearly related (r=0.72, p<0.001) and persisted at 2 years following surgery. The change in EDV was linearly related to the EF (r=0.35, p=0.02). The left-ventricular shape analysis showed improvements in the anterior and anterolateral segments (effect size=1.1, p<0.001) with nonsignificant changes in the inferior segments, conforming to an ellipsoid geometry. Linear endoventricular patch plasty restored a physiological elliptical ventricular geometry with persistent late reverse remodeling. The decreases in EDVs following surgery were significantly linearly proportional to the decreases in SVs at rest, which conforms to the normal left-ventricular geometry.