Severity of coronary artery stenosis at preoperative angiography and midterm mammary graft status

Background. The purpose of this study was to evaluate the correlation between the midterm angiographic results of mammary artery grafts and the preoperative stenosis of the target vessel. Methods. We analyzed preoperative and postoperative angiograms of 93 patients who underwent postoperative midterm (≥3 years) angiograms of an internal mammary artery (IMA) to left anterior descending artery graft for clinical or study purposes. Patients were divided into three groups on the basis of the percentage of the coronary artery stenosis at preoperative angiography: <70%, 70% to 90%, and >90% stenosis. Results. Preoperative characteristics were similar in the three groups. The overall incidence of IMA occlusion was 19% in the entire population, without significant differences between groups (19% versus 29% versus 14%). The mean mammary artery diameter significantly increased in direct proportion to the severity of the coronary stenosis (2.0 ± 0.2 mm in the <70% versus 2.5 ± 0.3 mm in the 70% to 90% and 2.7 ± 0.4 mm in the >90% series; p< 0.05). Conclusions. Chronic native competitive flow does not significantly affect midterm graft status but does influence mammary graft diameter.