Background: It has been shown that, among patients with ST-segment elevation myocardial infarction (STEMI), diabetes is associated with a significantly higher mortality. The aim of the current study was to investigate the impact of diabetes on myocardial perfusion and mortality among STEMI patients treated with primary angioplasty and glycoprotein IIb-IIIa inhibitors.
Methods: Our population is represented by a total of 1662 patients undergoing primary angioplasty for STEMI included in 11 randomized trials. Myocardial perfusion was evaluated by angiography (n=1324) or postprocedural ECG (n=1371). Distal embolization was defined as an abrupt "cutoff" in the main vessel or one of the coronary branches of the infarct-related artery, distal to the angioplasty site (data available in 1181 patients).
Results: Diabetes was observed in a total of 281 patients (16.9%). Diabetic patients were older, with a larger prevalence of female gender, hypertension, hypercholesterolemia, advanced killip class at presentation and multivessel disease. Diabetes was associated with impaired postprocedural TIMI 3 flow (82% vs 90%, p<0.001), MBG 2-3 (60.1% vs 74.2%, p<0.001), complete ST-segment resolution (43.2% vs 60%, p<0.001) and more distal embolization (16.4% vs 10.1%, p<0.0001). The association with impaired MBG and distal embolization was confirmed after correction for baseline confounding factors. Diabetes was associated with significantly impaired mortality (12.6% vs 3.9%, HR=3.0 [1.84-4.89], p<0.001), that persisted even after correction for baseline confounding factors (HR=2.6 [1.52-4.45], p=0.001).
Conclusion: This study showed that, among patients with STEMI undergoing primary angioplasty on the top of glycoprotein IIb-IIIa inhibitors, diabetes mellitus is independently associated with impaired perfusion and distal embolization, that contribute to explain the higher mortality observed in these patients.