Background: TIMI scale is commonly used for angiographic assessment of reperfusion effectiveness and early risk stratification in patients treated with primary angioplasty for ST-elevation myocardial infarction (STEMI). Since ST-resolution analysis allows a noninvasive insight into the reperfusion status at the myocardial tissue level, it may be a better predictor of outcome after primary angioplasty.
Aim: To compare the prognostic value of the reperfusion effectiveness evaluation based on either the epicardial blood flow assessment according to the TIMI scale, or ST-segment resolution analysis in patients treated with primary coronary angioplasty for STEMI.
Methods: 324 consecutive patients treated within 12 hours from the pain onset were studied. Based on the analysis of maximal ST-segment elevation/depression identified in a single ECG lead recorded after the procedure (maxSTE), patients were classified into groups of high versus medium/low risk. Independently, distinguished were groups with restored normal (TIMI 3) and abnormal (TIMI 0-2) final blood flow in infarct related artery.
Results: The 30-day and one-year mortality rates were higher in the high-risk maxSTE group (25% of all patients) than in the other patients (14.8% vs. 2.5%, p<0.001 and 18.5% vs. 5.4%, p<0.001 respectively). In subjects (82%) with restored TIMI grade 3 blood flow, mortality at one-month and one-year was lower than in the group with abnormal final blood flow (3.1% vs. 15.6%, p=0.001 and 6.2% vs. 18.8%, p=0.005). Comparison in multivariate analysis revealed that maxSTE stratification but not final TIMI grade assessment remained an independent predictor of both, 30-day and one-year mortality (high vs. medium/low-risk category; OR 5.3, 95% CI 1.6-16.7, p=0.005, and OR 3.3, 95% CI 1.4-7.8, p=0.007, respectively). Furthermore, maxSTE proved to stratify the risk of death even in subgroup of patients with restored normal blood flow (OR 6.2, 95% CI 1.4-27.8, p=0.016, and OR 3.0, 95% CI 1.1-8.7, p=0.039, respectively).
Conclusions: Analysis of extent of maximal ST-segment elevation or depression identified in a single ECG lead after primary coronary angioplasty allows better prognosis of subsequent 30-day and one-year mortality than the assessment of final epicardial blood flow, stratifying risk of death even in a subgroup of patients with restored normal blood flow.