NEW YORK (Reuters Health) – Patients with ST-elevation myocardial infarction (STEMI) who receive timely guideline-based reperfusion therapy — fibrinolysis within 30 minutes of arrival and primary percutaneous coronary intervention (PCI) within 90 minutes — are likely to have better outcomes that those who do not, according to a study in the June 2 issue of the Journal of the American Medical Association.

In their systematic evaluation of STEMI care, the authors found that ìtime, rather than mode of reperfusion, (was) a critical determinant of outcome. Regardless of reperfusion strategy, patients treated beyond maximum recommended delays had increased mortality.î

Indeed, whether patients received fibrinolytics or PCI, if the procedure was done outside the recommended timeframe they were at significantly higher risk for death within 30 days, and for the composite endpoint of death or readmission for acute MI or heart failure within 1 year.

The findings, from Dr. Laurie Lambert, of the Quebec Healthcare Assessment Agency, Montreal, Canada, and colleagues, are based on data from 80 hospitals in Quebec Province for 6 months in 2006-2007. International guidelines on reperfusion therapy for STEMI specify a maximum delay of 30 minutes for fibrinolysis and 90 minutes for primary PCI.

Among 1,832 patients with acute MI who received reperfusion therapy during the study period, 1,440 (78.6%) underwent primary PCI, with a median door-to-balloon time of 110 minutes. PCI was untimely (> 90 min) in 68% of patients. For the 392 patients (21.4%) who received fibrinolytic therapy, the median delay was 33 minutes, and untimely (> 30 min) in 54% of patients.

At 1 year, 13.5% of fibrinolysis patients and 13.6% of primary PCI patients had died or been readmitted for heart failure or acute MI.

When the researchers combined the 2 treatment groups, they found that patients with untimely therapies had a greater than twofold adjusted higher risk of death at 30 days (6.6% vs 3.3%; OR, 2.14), a 57% adjusted higher risk for the combined 1-year endpoint (15.0% vs 9.2; OR, 1.57), and a statistically nonsignificant increase in risk of death at 1 year (9.3% vs 5.2%; OR, 1.61), compared with patients treated within the recommended time frames.

The author of a commentary says, “Beyond these interesting and relevant results for individual patients, adjusted analyses at the regional level indicates that for each 10% increase in the number of patients treated within the guideline-recommended times, there was an associated 20% decrease in the region-level odds of dying at 30 days.î

“Thus, these results apply at not only the patient level but also the health systems level — an important observation with profound public health ramifications,” Dr. Deepak L. Bhatt of Brigham and Women’s Hospital, Boston writes.

“Perhaps in aggregate these results support regionalization of care for acute MI, although further research is needed,” Dr. Bhatt concludes.

Reference:

JAMA 2010;303:2148-2155,2188-2189.