Background: Biochemical markers have been suggested for the noninvasive diagnosis of reperfusion early after thrombolysis. Their ability to discriminate between Thrombolysis in Myocardial Infarction (TIMI) 2 and 3 flow grades remains unknown.
Methods: In 97 patients with myocardial infarction < or =6 hours, myoglobin, troponin T, MBCK, and MMCK isoforms were measured before thrombolysis and after 90 minutes. A 90-minute coronary angiography ascertained the potency status of the infarct-related artery in all patients according to the TIMI grade flow (group A: TIMI 0-1 (n = 35), group B: TIMI 2 (n = 17), and group C: TIMI 3 (n = 45). For each marker the absolute rate of increase and the relative increase 90 minutes after thrombolysis were studied.
Results: Both absolute values and absolute rates of increase at 90 minutes of myoglobin were higher in group B than in groups A and C (p < 0.05, not significant for other markers). Relative increases were consistently higher in group C than in other groups with statistical significance for myoglobin in the subset of patients treated for >3 hours.
Conclusion: Diagnostic indexes based on relative increases tend to discriminate between patients with TIMI 2 and 3 flow, and the best performance is obtained when the relative increase of myoglobin at 90 minutes is used in patients treated later than 3 hours after onset of symptoms.