Effect of patent complete revascularization on myocardium with persistent perfusion defects in preoperative single-photon emission computed tomography

Abstract

OBJECTIVES: This study aimed to evaluate the changes in perfusion assessed by myocardial single-photon emission computed tomography after coronary artery bypass grafting (CABG) and to examine the myocardial segments with persistent perfusion defect preoperatively in patients who underwent CABG and who had all patent grafts 1 year postoperatively. METHODS: Patients who underwent complete revascularization, who were assessed by preoperative and postoperative 3- and 12-month myocardial single photon emission computed tomography, and who showed all patent grafts on angiograms taken 1 year postoperatively were included. Myocardial single-photon emission computed tomography imaging was performed during stress and rest, and a 17-segment model was adopted for regional analysis of the perfusion defect. Myocardial segments were analysed based on a 5-point scale (0-4). After excluding the segments with normal stress scores, the difference scores (DSs) of the segments with impaired stress perfusion were calculated. The segments were divided into group P (DS <= 1) and group R (DS >= 2). RESULTS: Of 2057 myocardial segments from 120 patients, a total of 761 segments [segment group P (n = 572) vs segment group R (n = 189)] with impaired stress perfusion were included in the final analyses. The stress scores tended to decrease in both groups after the operation, although the changes in the stress perfusion scores over time were more significant in group R than in group P. The differences in the rest scores between groups P and R tended to decrease during postoperative year 1. Although the preoperative DSs were significantly lower in group P than in group R, the differences between the groups became insignificant during postoperative year 1. CONCLUSIONS: Complete revascularization including myocardium with persistent perfusion defect should be considered when performing CABG. The 2018 European guidelines on myocardial revascularization recommended non-invasive stress imaging to assess myocardial ischaemia and viability in patients with heart failure and coronary artery disease (CAD) before the decision on revascularization (class IIb, level of evidence B) [1].