NEW YORK (Reuters Health) – Reperfusing the myocardium within 5 hours of an infarction makes a real survival difference, research from Denmark shows.

The study, conducted in patients with ST-segment elevation myocardial infarction (STEMI), “shows that the faster we treat our patients, the greater is the likelihood of survival after a heart attack,” lead author Dr. Michael Maeng of Aarhus University Hospital, Skejby told Reuters Health by email.

In an April 16th online paper in the American Journal of Cardiology, Dr. Maeng and colleagues report 3 year follow-up data on 686 patients who had primary percutaneous coronary intervention (PCI) after STEMI. The median symptom-to-balloon time was about 3.5 hours. Patients were divided in to 3 groups according to whether the time to treatment was less than 3 hours, 3 to 5 hours or 5 hours or more.

Mortality was significantly increased in patients who waited the longest (hazard ratio 2.36). This effect persisted after adjustment for baseline differences (hazard ratio, 2.44).

In addition, a shorter symptom-to-balloon time improved the likelihood of Thrombolysis In Myocardial Infarction 3 flow after PCI; the authors documented this outcome in 86.5% of those treated within 3 hours, 80.9% of patients treated in the 3 to 5 hour window, and 75.7% in patients with reperfusion after more than 5 hours had elapsed.

Symptom-to-balloon times were also inversely correlated with left ventricular systolic ejection fractions (LVEF) of 40% or less. The rate of this outcome was 19.7% in the earliest treatment group, 22.8% in the intermediate group, and 33.1% in patients whose symptom-to-balloon interval was longer than 5 hours.

An LVEF at or below 40% was a major predictor of 3-year mortality (hazard ratio, 6.02) in this study.

Given the impact of timely PCI, Dr. Maeng said, “It is important that we organize the health care systems in a way that secures patients with a heart attack a fast and efficient treatment.”

Reference:

Am J Cardiol 2010.