Role of myocardial perfusion single photon emission CT (Sepct) in predicting improvement of myocardial function following revascularisation in patients with poor left ventricular function

Abstract

We used a combined rest-stress Tc-sestamibi redistribution imaging using SPECT scan to identify viable myocardium and predict improved left ventricular (LV) function after revascularisation in patients with severe LV dysfunction. 57 patients were studied retrospectively with severe LV dysfunction Ejection Fraction (EF)<30%. Regional and global LV functions were evaluated preop and 12 weeks post-coronry artery bypass grafting (CABG) with radionucleide ventriculography. Preoperatively, patients were classified into those with eight or more viable segments (out of 15 segments) and those with seven or less viable segments. 31 out of 43 (72%) patients with more than eight viable segments had shown significant improvement in LVEF (from 0.29 ± 0.01 to 0.36 ± 0.06) postoperatively. Out of the remaining 12 patients, 3 had persistent akinesia with deterioration of symptoms whereas others had shown sympomatic improvement. In the other group, 11 out of 14 patients (78%) with seven or less segments viable had not shown any improvement in their LVEF. The imaging also identified the segments that improved function after CABG. Out of a total 285 segments in 57 patients, 238 segments were studied. Among these, 178 segments were hypokinetic, 48 segments akinetic and 12 dyskinetic. Preoperatively, 160 out of 178 (90%) with hypokinesia had shown viability whereas 26/48 (54%) in akinetic group and 9/12 dyskinetic segments had shown viability with rest showing no viability. Postoperative imaging had shown improvement in these groups as follows: hypokinetic 88% (141/160); akinetic 62% (16/26); dyskinetic 48% (4/9). In patients with coronary artery disease (CAD)-and severely depressed LV function. preoperative imaging using SPECT identifies viability in many akinetic or dyskinetic myocardial segments, and these segments frequently improve function after CABG. The presence of numerous akinetic but viable myocardial segments before surgery correlated significantly with improvement in global LV function after bypass surgery.