Duration of Symptoms Is Not Always the Key Modulator of the Choice of Reperfusion for ST-Elevation Myocardial Infarction

Abstract

Fibrinolytic therapy (FT) and primary percutaneous coronary intervention (PCI) are both well-accepted reperfusion therapies in ST-segment elevation myocardial infarction (STEMI). The evidence of randomized clinical trials indicates a relatively modest difference in 30-day mortality (≈1%) in favor of primary PCI over fibrin-specific FT and was based on very timely primary PCI (ie, a primary PCI–related delay of 40 minutes [door-to-balloon less door-to-needle time]).1 Longer delays to primary PCI, which are far more frequent in clinical practice,2 are associated with attenuated benefit or no benefit at all, particularly when compared with fibrin-specific FT.3,4 The benefit of timely primary PCI over FT is likely to especially apply to higher-risk patients.5,6 Irrespective of the method of reperfusion, the potential for myocardial salvage and better clinical outcome is inversely proportional to ischemic time or its only available clinical surrogate, symptom duration.7–12 These considerations underpin the notion expressed in the American College of Cardiology/American Heart Association (ACC/AHA) guidelines on the treatment of STEMI that timely reperfusion therapy is likely more important in determining outcome than whether FT or primary PCI is the chosen reperfusion method.13 Response by Armstrong et al p 1310 The ACC/AHA STEMI guidelines highlight the time point of 3 hours of symptom duration in guiding the choice of reperfusion therapy. They state that if symptom duration is <3 hours, no preference exists between FT and primary PCI provided that treatment is timely (for FT, door-to-needle time <30 minutes; for primary PCI, door-to-balloon time <90 minutes and ≤60 minutes between estimated needle time and estimated balloon time). However, if symptom duration exceeds 3 hours, these guidelines favor primary PCI over FT, again provided that primary PCI can be performed in a timely fashion.13 This article reexamines the evidence that may or may not be the basis …