Aarhus, Denmark, and Boston, MA - Future revisions by the writing committee of the American College of Cardiology (ACC)/American Heart Association (AHA) guidelines for the management of STEMI patients [1] should consider extending the acceptable PCI-related delay to as long as 120 minutes, say Danish investigators [2].

Writing a viewpoint in the in the September 30, 2008 issue of the Journal of the American College of Cardiology, Dr Christian Terkelsen (Aarhus University Hospital, Denmark) and colleagues acknowledge that primary PCI is the superior reperfusion strategy when initiated in a timely fashion, but "in many regions it is difficult to establish a successful primary PCI strategy because it mandates optimal prehospital and in-hospital triage to ensure acceptable treatment delays."

They note that when transferring patients to a PCI-capable hospital, the updated guidelines consider 90 minutes an acceptable delay from the arrival of emergency medical services (EMS) to balloon. If 50 minutes is the acceptable EMS arrival-to-needle time, this leaves an acceptable extra delay when performing primary PCI instead of fibrinolysis of only 40 minutes.

"A maximal acceptable PCI-related delay of 40 minutes renders no patients eligible for transfer to primary PCI if the door-to-balloon time at the interventional hospital is 90 minutes," write the authors. "Even an in-the-door/out-the-door delay of only 30 minutes at the local hospital combined with an interhospital transfer time of only 10 minutes would mandate a door-to-balloon time of 30 minutes or less."

In a commentary countering the arguments put forth by the Danish researchers [3], Dr Elliott Antman (Brigham and Women's Hospital, Boston, MA), who cochaired the ACC/AHA guidelines for the management of STEMI patients, suggests that such arguments are unhelpful and do not help find ways to shorten total ischemic time, which is the most critical issue, because "time is muscle."

"Advances in the care of patients with STEMI in the future will not come from analysis of trials that do not reflect current practice in an effort to rationalize extending the PCI-related delay time," writes Antman.

In their defense of extending the PCI-related delay to beyond 90 minutes, Terkelsen and colleagues cite a pooled analysis of randomized clinical trials comparing primary PCI and in-hospital fibrinolysis in acute-MI patients [4]. The meta-analysis showed that primary PCI was superior to fibrinolysis even at PCI-related delays of 80 to 120 minutes, although Antman and others point out that the reperfusion strategies were below today's standard of care.

In his commentary, Antman notes that most EMS systems in the US do not have teams trained in the administration of prehospital fibrinolysis, and that is why the guidelines emphasize delivering the drug within 30 minutes of patient presentation at the hospital. Also important are efforts to shorten the time to primary PCI through the early activation of the catheterization laboratory, possibly on route to the PCI hospital.

The D2B Alliance campaign launched in 2006 by the ACC, in collaboration with the AHA, the American College of Emergency Physicians (ACEP), the National Heart, Lung, and Blood Institute (NHLBI), and other partners is central to efforts to decrease door-to-balloon times in primary PCI, notes Antman. So far, roughly 1000 hospitals are participating, with the goal to achieve the recommended time of less than 90 minutes for at least 75% of nontransferred patients.

Terkelsen and colleagues suggest that the D2B Alliance also consider expanding their strategies and implement out-of-hospital initiatives, given that the majority of patients with STEMI live in the catchment area of non-PCI hospitals. Focusing on prehospital diagnosis, activation of the catheterization lab, and rerouting to a primary PCI center running 24 hours/day, seven days/week could help reduce the delay, as would admitting patients directly to the catheterization lab.