Background and aim: The aim of our study was to determine the influence of diabetes mellitus (DM) on myocardial reperfusion and left ventricular (LV) remodelling in patients with an acute myocardial infarction undergoing primary percutaneous coronary intervention.

Methods: The study population consisted of 218 patients with first anterior ST-segment elevation myocardial infarction (STEMI) successfully treated with primary coronary angioplasty. We evaluated microvascular reperfusion using angiographic (Myocardial Blush Grade [MBG]) as well as electrocardiographic methods (ST-segment resolution > 70%). LV remodelling was defined asan increase in end-diastolic volume ≥ 20%, based on repeated measurements in individual patients. The study population was divided into two groups according to the presence, n = 43 (20%), or absence, n = 175 (80%), of DM.

Results: Patients with DM showed a significantly higher rate of MBG ≤ 2 (45.7% vs. 62.8%, p = 0.04) and lower incidence of ST-segment resolution > 70% (48% vs. 18.6%, p = 0.0003) compared to non-diabetics. Despite a similar incidence of LVremodelling in DM and non-DM groups (30.2% vs. 22.4%, p = 0.27), echocardiographic features of diastolic impairment and overt symptoms of heart failure were significantly more frequent in diabetic patients (55.2% vs. 27.1%, p = 0.006 and 36.1% vs. 18.3%, p = 0.02, respectively) at six-month follow-up.

Conclusions: Despite worse microvascular reperfusion in STEMI patients with diabetes, the incidence of LV remodelling was similar compared to non-DM patients. DM was associated with the development of diastolic heart failure.