Abstract 1677: Variable Association of Hyperemic Epicardial Flow with Adverse Outcomes Among Patients Treated with Fibrinolytic Therapy for ST-Segment Elevation Myocardial Infarction: An Analysis From CLARITY-TIMI 28
Background: Hyperemic epicardial arterial flow following reperfusion therapy for STEMI could be the consequence of two etiologies:
the physiologic repayment of oxygen debt or
release of adenosine and other endogenous vasodilators due to embolization of platelet aggregates and thrombotic debris. The association between hyperemic flow in the infarct-related coronary artery and outcomes has not been fully explored.
Methods: In CLARITY-TIMI 28, STEMI patients (n=3,491) treated with fibrinolytic therapy were scheduled to undergo angiography 48–192 hours after randomization. The TIMI Flow Grade (TFG), Frame Count (CTFC) and Myocardial Perfusion Grade (TMPG) were assessed, and their association with morbidity and mortality at 30 days was evaluated.
Results: Locally weighted polynomial regression using the LOESS technique demonstrated a U-shaped relationship between the post-PCI or final diagnostic angiographic CTFC and 30-day mortality. Indeed, hyperemic flow (CTFC <14), slow flow (CTFC >28) and an occluded artery (TFG 0 or 1) were all associated with higher mortality, recurrent MI or a composite of the two when compared to a normal CTFC of 14–28 (p<0.02 for all). The association between hyperemic flow (CTFC <14) and higher mortality was observed exclusively among patients with TMPG of 0 or 1 (3.0%), whereas a CTFC <14 with normal perfusion (TMPG 2/3) was associated with a low incidence of 30-day mortality (0.6%) (Figure⇓).
Conclusion: Hyperemic flow on coronary angiography when observed in the presence of abnormal perfusion (TMPG 0/1) is associated with an increased incidence of mortality and may be a marker of more extensive downstream microembolization.