Influence of Diabetes on 5-Year Mortality and Morbidity in a Randomized Trial Comparing CABG and PTCA in Patients With Multivessel Disease

Abstract

Background Patients with diabetes mellitus have increased morbidity and mortality after coronary revascularization. The Bypass Angioplasty Revascularization Investigation (BARI), a trial of percutaneous transluminal coronary angioplasty (PTCA) versus coronary artery bypass graft surgery (CABG) in patients with multivessel disease, reported a 5-year survival advantage of CABG over PTCA in patients with treated diabetes mellitus (TDM). This report examines these findings in more detail. Methods and Results Eighteen clinical centers randomly assigned 1829 patients with multivessel coronary disease to undergo initial CABG or PTCA. Patients were followed an average of 5.4 years. TDM was defined as a history of diabetes with use of oral hypoglycemic agents or insulin at study entry. Nineteen percent of the randomized population (353 patients) met these criteria. TDM patients had more unfavorable baseline characteristics than other patients, but among TDM patients, these characteristics were similar between the CABG and PTCA groups. Better average 5.4-year survival with CABG was due to reduced cardiac mortality (5.8% versus 20.6%, P =.0003), which was confined to those receiving at least one internal mammary artery graft. Conclusions Patients with TDM assigned to an initial strategy of CABG have a striking reduction in cardiac mortality compared with PTCA. Long-term internal mammary artery graft patency may contribute to this improved outcome by reducing the fatality of follow-up myocardial infarction.

Recognition of the Importance of Embolization in Atherosclerotic Vascular Disease

“…[53][54][55][56][57] Of demographic features, diabetes mellitus stands out as 1 with particular risk, such as increased mortality after coronary intervention. 58 This could be attributed to the diffuseness of atherosclerotic involvement, extent of preexisting microvascular disease that reduces the adaptive capacity to embolization, or heightened inflammation related to insulin, S-glycolation products, or other metabolic factors. There may well be genotypic features that will be useful for identifying patients who have a propensity to embolize or cannot accommodate particulate matter.…”

Patency of Percutaneous Transluminal Coronary Angioplasty Sites at 6-Month Angiographic Follow-Up

“…2 This unique behavior suggests a specific interaction between diabetes mellitus and the "response" of coronary vessels to balloon angioplasty. Although several possible mechanisms have been suggested for this diabetes-PTCA interaction, 9 -12 no conclusive explanation has been provided.…”

“…However, one of the most intriguing findings in several different studies was the fact that diabetics had a relatively low rate of in-hospital complications and that the detrimental effects of angioplasty became apparent only at a distance from the procedure. 2,6,8 Considering this observation, as well as biological and epidemiolog- Statistical analysis was performed using baseline and follow-up characteristics presented in Tables 1 and 2. Variables with PϾ0.10 are not presented.…”

Risk stratification in diabetes: Not all patients or perfusion defects are the same

“…4 In clinical studies, these factors also play into the prognosis of diabetic patients with acute myocardial infarction or those undergoing coronary intervention or bypass surgery. 3,5 Barmpouletos et al 6 herein present the results of a retrospective analysis, suggesting that simple clinical features improve the risk stratification conferred by stress myocardial perfusion imaging in patients with diabetes. These results are potentially highly relevant to the interpretation of test results by nuclear cardiologists.…”

“…2 When symptomatic CAD is present, there is an even greater concern, because of the potential for advanced atherosclerosis, which carries a very high risk for adverse cardiac outcomes. 3 In epidemiological studies, it is recognized that the cardiovascular risk of diabetes is related to the duration of diabetes and whether it requires insulin for glycemic control. 4 In clinical studies, these factors also play into the prognosis of diabetic patients with acute myocardial infarction or those undergoing coronary intervention or bypass surgery.…”