Perioperative predictors of early silent coronary graft occlusion after direct myocardial revascularisation

Background. The condition of the coronary grafts is the most important determinant of prognosis after direct myocardial revascularisation. Previous studies mainly aimed at exploring the long-term patency and causes of coronary graft occlusions; identification of patients at risk for asymptomatic graft occlusion in the early postoperative period remains an unresolved issue. Aim. The purpose of this study was to define perioperative predictors of early asymptomatic coronary graft occlusion after direct myocardial revascularisation. Methods. This retrospective study included 201 patients with coronary artery disease who underwent microscope-assisted coronary artery (CA) bypass surgery in 2013-2018. All patients underwent 64-slice computed tomography angiography 7 days after surgery. The patients were categorised into two groups: those with confirmed patency of all coronary grafts (n = 153; group I) and those with occlusion of at least one graft (n = 48; group II). The perioperative predictors of early asymptomatic coronary graft occlusion were analysed using logistic regression. Results. The total graft patency was 91.7% among a total of 650 coronary grafts that were examined. The frequencies of mammary and venous graft occlusions were comparable (8.4% and 8.2%, respectively). No differences were noted in the conduit types or the revascularised areas of the myocardium between the two groups. Multivariate regression analysis revealed that diffuse CA lesions (odds ratio [OR], 2.74; 95% confidence interval [CI], 1.36-5.52; p = 0.005), lesion diameter of CA of 7.8 mmol/l) during the first postoperative day (OR, 4.22; 95% CI, 1.70-10.5; p = 0.002) were independent predictors of early coronary graft occlusion. History of percutaneous coronary intervention (OR, 0.32; 95% CI, 0.11-0.97; p = 0.045) and increased baseline glomerular filtration rate (OR, 0.96; 95% CI, 0.93-0.98; p = 0.002) were associated with a reduced risk of early graft occlusion. Conclusion. The frequency of early asymptomatic occlusion after microscope-assisted coronary artery bypass surgery was comparable between the venous and mammary grafts and did not depend on the anatomical zone of myocardial revascularisation. Diffuse CA lesions, target CA diameter of 7.8 mmol/L) during the first postoperative day were associated with an increased risk of early silent graft occlusion, whereas increased baseline glomerular filtration rate and history of percutaneous coronary intervention were protective for the early patency of coronary bypass grafts.