Sobel, Burton E.

Background— Effects were compared in patients in the Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) trial of 2 mechanistically different strategies for treatment of hyperglycemia, insulin-sensitizing and insulin-providing strategies, on biomarker profiles reflecting the balance between fibrinolysis and thrombosis and the intensity of inflammation implicated in diabetic vasculopathy. Methods and Results— A total of 2368 patients with type 2 diabetes mellitus and clinically stable, angiographically documented coronary artery disease were randomized to treatment with 1 of the 2 strategies and followed for an average of 5 years. Plasminogen activator inhibitor type 1 antigen and activity, tissue plasminogen activator antigen, fibrinogen, D-dimer, C-reactive protein, insulin, and hemoglobin A 1c were assayed in blood samples acquired at baseline and at 12 regular intervals throughout the follow-up interval. Higher baseline D-dimer, fibrinogen, and C-reactive protein portended a poor prognosis in patients in both groups. In contrast to the insulin-providing strategy, the insulin-sensitizing strategy led to (1) lower plasma insulin; (2) lower plasminogen activator inhibitor type 1 antigen and activity and lower tissue plasminogen activator antigen (known to track with plasminogen activator inhibitor type 1); and (3) lower C-reactive protein and fibrinogen at all intervals after baseline ( P <0.001 for each). Conclusions— The insulin-sensitizing treatment strategy led to changes in biomarker profiles indicative of decreased insulin resistance, an altered balance between thrombosis and fibrinolysis favoring fibrinolysis, and diminished intensity of the systemic inflammatory state, factors that have been associated with cardiovascular risk. Clinical Trial Registration— http://www.clinicaltrials.gov . Unique identifier: NCT00006305.

Background Inhibition of leukocyte adhesion can reduce myocardial infarct size in animals. This study was designed to define the safety and efficacy of a recombinant, humanized, monoclonal antibody to the CD18 subunit of the β2 integrin adhesion receptors (rhuMAb CD18), in reducing infarct size in patients treated with a thrombolytic agent. Methods and Results The Limitation of Myocardial Infarction following Thrombolysis in Acute Myocardial Infarction Study (LIMIT AMI) was a randomized, double-blind, placebo-controlled, multicenter study conducted in 60 centers in the United States and Canada. A total of 394 subjects who presented within 12 hours of symptom onset with ECG findings (ST-segment elevation) consistent with AMI were treated with recombinant tissue plasminogen activator and were also given an intravenous bolus of 0.5 or 2.0 mg/kg rhuMAb CD18 or placebo. Coronary angiography was performed at 90 minutes, 12-lead ECGs were obtained at baseline, 90, and 180 minutes, and resting sestamibi scans were performed at ≥120 hours. Adjunctive angioplasty and use of glycoprotein IIb/IIIa antiplatelet agents at the time of angiography were discretionary. There were no treatment effects on coronary blood flow, infarct size, or the rate of ECG ST-segment elevation resolution, despite the expected induction of peripheral leukocytosis. A slight trend toward an increase in bacterial infections was observed with rhuMAb CD18 ( P =0.33). Conclusions RhuMAb CD18 was well tolerated but not effective in modifying cardiac end points.

A paradoxical increase in mortality attributable to diabetes has occurred, particularly during the last decade, despite the overall decrease in mortality attributable to coronary artery disease in patients without diabetes. Insulin resistance with or without frank type 2 diabetes has emerged as a major determinant of accelerated coronary artery disease and its sequelae. The advent of insulin sensitizers enables clinicians to target treatment of insulin resistance, as well as hyperglycemia and dyslipidemia. The prevalence of diabetes in the United States is enormous and is increasing rapidly. Patients with diabetes respond less favorably to percutaneous coronary interventions and surgery compared with nondiabetic patients. These considerations led to the initiation of the Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) trial. It is designed to determine whether treatment targeted to attenuate insulin resistance can arrest or retard progression of coronary artery disease compared with treatment targeted to the same level of glycemic control with an insulin-providing approach. It is designed also to determine whether early revascularization reduces mortality and morbidity in patients with type 2 diabetes whose cardiac symptoms are mild and stable. Despite challenges in study design and enrollment, intensive follow-up, and the long duration of follow-up planned, the questions being addressed are compelling and seem to merit the effort.

Background — The TIMI myocardial perfusion grade (TMPG) and ST-segment resolution both reflect perfusion and are associated with mortality after thrombolysis for acute myocardial infarction. We hypothesized that these measures would also be associated with infarct size by single photon emission computed tomography (SPECT). Methods and Results — In the LIMIT AMI trial (Limitation of Myocardial Injury following Thrombolysis in Acute Myocardial Infarction) of lytic monotherapy versus lytic plus rhuMAb CD18, early 90-minute TMPG (n=221) and ST segment resolution (n=242) were compared with subsequent SPECT Technetium-99 m Sestamibi, measuring the percentage of the left ventricle with no Sestamibi uptake. Infarct sizes were larger with TMPG 0 or 1 (a closed or stained myocardium) than with TMPG 2 or 3 (open myocardium, median 13% versus 7%, P =0.004). Infarcts were also larger in patients with no ST segment resolution (median 15%) or incomplete resolution (11%) than in those with complete resolution (6%, overall P =0.0001). The difference in infarct size by TMPG persisted when stratified by category of ST resolution. Conclusions — There may be a pathophysiological link between early restoration of tissue-level perfusion and reduced subsequent infarct size that may partially explain why these early angiographic and electrocardiographic measures are associated with long-term survival.