ATHEROSCLEROSIS OF THE INTERNAL MAMMARY ARTERY IN PATIENTS UNDERGOING CORONARY ARTERY BYPASS GRAFTING

Abstract

In patients requiring coronary artery bypass grafting (CABG), usually at least one of the internal mammary arteries is used. This study evaluates the degree of atherosclerotic involvement of the internal mammary artery (IMA) in patients undergoing CABG. During two months period, 79 patients (66 male and 13 female with a medium age of 58 years) undergoing myocardial revascularization had a biopsy of the distal left internal mammary artery. In our study atherosclerotic involvement of the IMA was assessed according to the scale of Kay. Using this index, grade 0 corresponds to a normal artery without atherosclerosis, grade 1 represents minimal disease, grade 2 a narrowing of less than 25% of the lumen, grade 3 narrowing between 25 and 50%, and grade 4 narrowing of 50% or greater of the lumen. Of the 79 IMAs examined, the arteries with degree 0, 1, 2, 3, and 4 were: 17 (21.5%), 36 (45.6%), 13 (16.5%), 10 (12.7%), and 3 (3.8%), respectively. Considering the arteries with severe atherosclerotic narrowing (3.8%), the IMA had a low but consistent incidence of atherosclerotic involvement. According to our investigation among risk factors only high blood pressure has some roles in inducing atherosclerotic changes (p=0.014). The other risk factors (i.e. diabetes mellitus, smoking, hyperlipidemia) had no correlation with the atherosclerotic changes in IMA. Preoperative angiography of the IMA is not necessary for all the patients that require CABG, but could be recommended in hypertensive patients.