Unsuccessful reperfusion in patients with ST-segment elevation myocardial infarction treated by primary angioplasty.

BACKGROUND: Several studies have shown that patency of the epicardial vessel does not guarantee optimal myocardial perfusion in patients undergoing primary angioplasty for ST-segment elevation myocardial infarction (STEMI). The aim of the current study was to identify clinical and angiographic correlates of unsuccessful reperfusion by the use of myocardial blush grade in a large consecutive cohort of STEMI patients.

METHODS: Our population is represented by a total of 1,548 consecutive patients with STEMI treated by primary angioplasty at our institution. All clinical and angiographic data were prospectively collected. Successful reperfusion was defined as postprocedural thrombolysis in myocardial infarction (TIMI) 3 flow with myocardial blush grades 2 to 3.

RESULTS: Poor myocardial reperfusion was observed in 358 patients (23.1%) and was associated with a significantly larger infarct size (1838 [350-3387] vs 1187 [607-2257], P < .0001) and lower ejection fraction (41 [31-48.2] vs 65 [36.5-52.5] P < .0001). At multivariate analysis, preprocedural TIMI flow 0 to 1, anterior infarction, ischemic time, postprocedural residual stenosis, advanced Killip class at presentation, and age were identified as independent predictors of poor myocardial reperfusion. At 1-year follow-up, a total of 92 patients (5.9%) had died. At multivariate analysis, including clinical and angiographic variables, unsuccessful reperfusion was an independent predictor of 1-year mortality (relative risk 3.11, 95% CI 1.99-4.87, P < .0001).

CONCLUSIONS: The prevalence of poor myocardial reperfusion is relatively high in patients undergoing primary angioplasty for STEMI, with a significant impact on 1-year mortality. Preprocedural TIMI flow, anterior infarction, ischemic time, Killip class at presentation, and age were independently associated with unsuccessful reperfusion. Future research should be focused on these high-risk patients, and treatment strategies should be developed to improve myocardial perfusion and clinical outcome.