Schwartz, Leonard

Background— Few studies have compared long-term status of bypass grafts between patients with and without diabetes, and uncertainty exists as to whether diabetes independently predicts poor clinical outcome after CABG. Methods and Results— Among 1526 patients in BARI who underwent CABG as initial revascularization, 99 of 292 (34%) with treated diabetes mellitus (TDM) (those on insulin or oral hypoglycemic agents) and 469 of 1234 (38%) without TDM had follow-up angiography. Angiograms with the longest interval from initial surgery and before any percutaneous graft intervention (mean 3.9 years) were reviewed. An average of 3.0 grafts were placed at initial CABG for patients with TDM (n=297; internal mammary artery [IMA], 33%) and 2.9 grafts for patients without TDM (n=1347; IMA, 34%). Patients with TDM were more likely than those without to have small (<1.5 mm) grafted distal vessels (29% versus 22%) and vessels of poor quality (9% versus 6%). On follow-up angiography, 89% of IMA grafts were free of stenoses ≥50% among patients with TDM versus 85% among patients without TDM ( P =0.23). For vein grafts, the corresponding percentages were 71% versus 75% ( P =0.40). After statistical adjustment, TDM was unrelated to having a graft stenosis ≥50% (adjusted odds ratio, 0.87; 95% CI, 0.58 to 1.32). Conclusions— Despite diabetic patients’ having smaller distal vessels and vessels judged to be of poorer quality, diabetes does not appear to adversely affect patency of IMA or vein grafts over an average of 4-year follow-up. Previously observed differences in survival between CABG-treated patients with and without diabetes may be largely a result of differential risk of mortality from noncardiac causes.

Background — Data are absent that compare midterm angiographic outcome between patients with and without diabetes after initial percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass graft surgery (CABG). Importantly, diabetes mellitus may differentially influence long-term survival after PTCA or CABG. Methods and Results — Patients with multivessel coronary disease who were previously enrolled in the Bypass Angiopathy Revascularization Investigation to compare initial PTCA versus CABG (n=1829) and who had a reduction in jeopardized myocardium after initial revascularization and at least 1 angiogram during 5-year follow-up were analyzed (n=897). This included 369 CABG-treated patients (16% with diabetes) and 528 PTCA-treated patients (18% with diabetes). The influence of diabetes on angiographic increase in percentage of jeopardized myocardium after initial revascularization with either PTCA or CABG was investigated. Among PTCA patients, the mean percentage increase in total jeopardized myocardium was significantly greater in those with diabetes than in those without at 1-year protocol-directed angiography (42% versus 24%, P =0.05) and on the first clinically performed (unscheduled) angiogram within 30 months (63% versus 50%, P =0.01) but not at 5-year protocol-directed angiography (34% versus 26%, P =0.33). This excess midterm risk associated with diabetes persisted after statistical adjustment. In contrast, among CABG patients, diabetes was not associated with percentage increase in jeopardized myocardium at any angiographic follow-up interval. Conclusions — Presence of diabetes differentially influences worsening of jeopardized myocardium after initial PTCA compared with CABG. This differential effect occurs irrespective of whether follow-up angiography is undertaken for clinical or nonclinical purposes.