Objective: We evaluated the incidence and predictive factors of impaired microcirculation, defined as myocardial blush grade (MBG) 0, in patients undergoing primary angioplasty for ST-elevation myocardial infarction.
Methods: Since 2001, in our province a network has been operating for the treatment of ST-elevation myocardial infarction based on the use of primary angioplasty in all high-risk patients and, up to December 2005, 530 patients were treated. Core angiographic analysis was performed, and images were technically adequate to assess epicardial and myocardial perfusion rates in 530 patients. Outcomes were examined according to postprocedural myocardial blush.
Results: Patients with MBG 0-1 had more diabetes and previous anterior myocardial infarction, longer delay to mechanical reperfusion, higher baseline mean leukocyte count, higher baseline C-reactive protein level as well as higher in-hospital mortality. The correlation between MBG, Thrombolysis in Myocardial Infarction (TIMI) flow grade and ST-segment resolution suggests that MBG is an optimal marker of reperfusion.
Conclusions: Our results indicate that a fair percentage of patients with TIMI 3 flow after primary angioplasty do not show signs of effective reperfusion (MBG 0) and have a higher in-hospital mortality rate. Myocardial reperfusion after primary angioplasty, as assessed by MBG, strongly correlates with other markers of reperfusion success, including ST-segment resolution.