Impact of diabetes mellitus on epicardial and microvascular flow after fibrinolytic therapy

Background: Patients with diabetes are at increased risk of death after acute myocardial infarction, independent of other baseline risk factors and more severe coronary artery disease. We studied the angiographic and electrocardiographic responses to thrombolytic agents in patients with diabetes; in particular ST-segment resolution as a measure of microvascular flow. Methods: Angiography was performed in 2588 patients at 90 minutes after thrombolytic agent administration as well as after percutaneous coronary intervention (PCI) in the Thrombolysis In Myocardial Infarction (TIMI) 4, 10A, 10B, and 14 trials. Electrocardiographic parameters were assessed at baseline and at 90 minutes in the TIMI 14 trial. Results: Compared with those without diabetes, patients with diabetes (347/2588 [13.4%]) were older, more often female, heavier, and less often smokers, and they had higher systolic blood pressure on admission. At angiography, they more frequently had 3-vessel disease, well-developed collateral vessels, more distal culprit lesions, and smaller reference segment diameters. In the infarct-related artery, there was no relationship between diabetes and TIMI 3 flow at 90 minutes (55.4% vs 59.0% without diabetes) or after PCI, (83.7% vs 84.2%, both P = NS). Corrected TIMI frame counts were also similar at both time points. However, there was less frequent complete ST-segment resolution among diabetic patients after thrombolysis (38.6% vs 49.2%, adjusted P = .04). Conclusion: Thrombolysis and adjunctive/rescue PCI achieved equal rates of epicardial flow in patients with and without diabetes. However, diabetic patients had less complete ST-segment resolution, suggesting impaired microvascular flow. Abnormal microvascular flow may contribute at least in part to the poorer outcomes observed in patients with diabetes and acute myocardial infarction.