Commentary

RCTs suggest that primary percutaneous coronary intervention (PCI) is a more effective reperfusion strategy than fibrinolysis for the treatment of acute ST segment elevation MI. There is not much debate about the superiority of PCI in reducing reinfarction and stroke rates and hospital length of stay. However, primary PCI is not widely available and substantial time delays in delivery limit the mortality benefit.

Time to treatment and access to expert PCI are critical issues. In the review by Keeley et al, the PCI related time delay in the RCTs was only 40 minutes, but this varied widely from patient to patient and study to study. It is likely that delays are longer in clinical practice in many communities for several logistical reasons. Also, most of the patients receiving PCI were treated by experienced interventionalists in high volume laboratories. Current guidelines state that hospitals should do ≥200 PCI procedures per year, operators should do ≥75 PCI procedures per year, and door to balloon time should be <120 minutes.¹ Otherwise, fibrinolysis is preferred. Hospitals aiming to achieve the same mortality benefit with PCI as that shown in RCTs will have to match their short times to treatment and procedure success rates.

Interhospital transfer for primary PCI, instead of on site fibrinolysis, has recently been promoted by 5 studies,² but the PCI related time delay was 44 minutes, which can only be accomplished in some communities in North America. Primary PCI done at certified hospitals without on site cardiac surgery or initial transport of patients to PCI centres is a better strategy to reduce PCI related time delay. Prehospital fibrinolysis is another mortality reduction strategy and may be preferred in communities where local, expert PCI is not available. The concept that treatment delay up to 3 hours is acceptable for primary PCI instead of fibrinolysis is not supported by current data.

Primary PCI is particularly beneficial in patients who are elderly, have heart failure or cardiogenic shock, or present late. Fibrinolysis with symptom duration <2 hours can salvage substantial myocardium with early reperfusion and may be preferable to PCI. Preinterventional laboratory half dose fibrinolysis (facilitated PCI) and rescue PCI for unsuccessful fibrinolysis may offer a superior reperfusion strategy than either fibrinolysis or primary PCI alone.