Abstract 4711: The absence of Diabetes is the Major Determinant of Reversible Mycrovascular Obstruction after Acute Myocardial Infarction
Purpose: Few data are available on dynamic changes of tissue level perfusion in the first week after primary percutaneous coronary intervention (PPCI). We sought to investigate incidence, determinants and long-term clinical significance of reversible microvascular obstruction (MVO) after PPCI.
Methods: Serial echocardiograms (2DE) and myocardial contrast study were obtained within 24 hrs of coronary recanalization (T1) and at pre-discharge (T2) in 110 successfully reperfused ST- segment elevation acute myocardial infarction (STEMI) patients. In-hospital MVO changes were quantitatively assessed by measuring contrast defect length (CDL%) at T1 and T2. Follow-up 2DE was scheduled after 6 months. Two-years clinical follow-up was obtained.
Results: After coronary revascularization myocardial perfusion was normal in 39 patients (35%, Group 1, aborted infarction) and remained normal at discharge. CDL% was reduced or completely disappeared at discharge in 33 patients (31%, Group 2, reversible MVO) whereas didn’t change in 38 patients (in 34%, group 3, sustained MVO). At 6 months follow-up, a significant reduction in wall motion abnormalities extent (WMA%) with parallel decrease in left ventrciular end diastolic volume (LVEDV) and improvement in LV ejection fraction (LVEF%) was observed in Groups 1 and 2 . Conversely, no changes in WMA extent and a significant increase in LVEDV with parallel worsening in LVEF% was observed in patients with sustained MVO. By multivariate analysis, the only independent predictor of reversible MVO was the absence of diabetes ((OR: 8.39(1.06 – 66), P=0.043). Finally among patients with MVO at first control after coronary reperfusion, 2-year combined events rate was significantly lower in patients with reversible MVO (log-rank test P= 0.03) as compared to patients with persistent MVO.
Conclusions: In STEMI patients, spontaneous changes in tissue level perfusion within the infarct zone can occur in the first week after PPCI and are strongly dependent by the presence of diabetes. The persistence of MVO at discharge is an important predictor of unfavourable long-term outcome.