Impact of surgical ventricular reconstruction on sphericity index in patients with ischaemic cardiomyopathy: Follow-up from the STICH trial

Aims We sought to evaluate associations between baseline sphericity index (SI) and clinical outcome, and changes in SI after coronary artery bypass graft (CABG) surgery with or without surgical ventricular reconstruction (SVR) in ischaemic cardiomyopathy patients enrolled in the SVR study (Hypothesis 2) of the Surgical Treatment for Ischemic Heart Failure (STICH) trial. Methods and results Among 1000 patients in the STICH SVR study, we evaluated 546 patients (255 randomized to CABG alone and 291 to CABG + SVR) whose baseline SI values were available. SI was not significantly different between treatment groups at baseline. After 4 months, SI had increased in the CABG + SVR group, but was unchanged in the CABG alone group (0.69±0.10 to 0.77±0.12 vs. 0.67±0.07 to 0.66±0.09, respectively; P < 0.001). SI did not significantly change from 4 months to 2 years in either group. Although LV end-systolic volume and EF improved significantly more in the CABG + SVR group compared with CABG alone, the severity of mitral regurgitation significantly improved only in the CABG alone group, and the estimated LV filling pressure (E/A ratio) increased only in the CABG + SVR group. Higher baseline SI was associated with worse survival after surgery (hazard ratio 1.21, 95% confidence interval 1.02-1.43; P = 0.026). Survival was not significantly different by treatment strategy. Conclusion Although SVR was designed to improve LV geometry, SI worsened after SVR despite improved LVEF and smaller LV volume. Survival was significantly better in patients with lower SI regardless of treatment strategy.