The preoperative myocardial perfusion and internal mammary artery graft blood flow relationship in patients with ischemic cardiomyopathy

Abstract

Objective. The purpose of this study was to determine the association between preoperative myocardial perfusion data (obtained by SPECT) with transit time blood flow characteristics in left internal mammary artery (LIMA) to left anterior descending artery (LAD) grafts in patients with ischemic cardiomyopathy.Methods. The study group consisted of 57 patients with ischemic cardiomyopathy. Intraoperative transit-time flow measurement (TTFM) of LIMA-LAD grafts were performed in all patients. All patients were also examined with preoperative stress and rest myocardial perfusion SPECT with 99m Tc-MIBI. Anastomotic patency was considered satisfactory with a normal waveform of blood flow, diastolic-dominant blood filling, and a mean flow value greater than 11.5 ml/min.Results. All 57 patients with LIMA-LAD grafts were divided into two groups; those with graft satisfactory patency (n = 40) and those with unsatisfactory patency (n = 17) as determined by TTFM. We found differences among these groups in values of global summed rest score (20.7 ± 7.5 vs. 29.8 ± 4.0; p = 0.002), global total perfusion deficit (TPD) at rest (32.0 ± 11.4 vs. 43.0 ± 7.2; p = 0.01), and regional TPD at rest in the LAD territory (20.7 ± 7.5 vs. 29.8 ± 4.0; p = 0.002). Additionally, the flow characteristics were different in patients with and without surgical left ventricle reconstruction (Q (ml/min): 17 (11.5, 40.8) vs. 47 (25, 69.5), p = 0.013; PI: 3.9 (3.2, 7.4) vs. 2.4 (2.0, 3.6), p = 0.001; DF (%): 63.5 (44.5, 70.8) vs. 74 (66.0, 79.7), p = 0.019). TPD at rest was the best predictor of the LIMA-LAD graft satisfactory: area under curve = 0.771, cut-off value = 26.85 with 83.3% sensitivity and 78.1% specificity.Conclusions. Preoperative myocardial perfusion characteristics are associated with blood flow in LIMA-LAD graft in patients with ischemic cardiomyopathy. TPD at rest (assessed globally and in the LAD region) as well as global SRS value are potential predictors of early graft failure.