Objectives: We sought to determine if an underlying mechanism of the association between prolonged symptom-to-treatment times and adverse outcomes may be an association of symptom-to-treatment times with impaired Thrombolysis In Myocardial Infarction myocardial perfusion grades (TMPGs).
Background: Prolonged symptom duration among ST-segment elevation myocardial infarction (STEMI) patients undergoing fibrinolytic therapy is associated with adverse outcomes.
Methods: Angiography was performed 60 min after fibrinolytic administration in 3,845 Thrombolysis In Myocardial Infarction (TIMI) trial patients.
Results: The median time from symptom onset to treatment was longer among patients with impaired myocardial perfusion (3.0 h for TMPG 0/1 vs. 2.7 h for TMPG 2/3; p = 0.001). In a multivariate model, impaired tissue perfusion (TMPG 0/1) remained associated with increased time to treatment (odds ratio 1.14 per hour of delay; p = 0.007) even after adjusting for Thrombolysis In Myocardial Infarction flow grade (TFG) 3, left anterior descending infarct location, and baseline clinical characteristics. Impaired myocardial perfusion after rescue/adjunctive percutaneous coronary intervention (PCI) was associated with longer median times to treatment (3.0 h for TMPG 2/3 vs. 2.7 h for TMPG 0/1; p = 0.017), as was abnormal epicardial flow after rescue/adjunctive PCI (3.3 h for TFG 0/1/2 vs. 2.8 h for TFG 3; p = 0.005). Thirty-day mortality was associated with longer time from onset of symptoms to treatment (6.6% mortality for time to treatment >4 h vs. 3.3%; p < 0.001), even among patients undergoing rescue PCI.
Conclusions: A prolonged symptom to treatment time among STEMI patients is associated with impaired myocardial perfusion independent of epicardial flow both immediately after fibrinolytic administration and after rescue/adjunctive PCI. These data provide a pathophysiologic link between prolonged symptoms due to vessel occlusion, impaired myocardial perfusion, and poor clinical outcomes.