TIME MORE IMPORTANT THAN TYPE OF REPERFUSION THERAPY

June 8, 2010 (Montreal, Quebec) — Reperfusion therapy delivered outside guideline-recommended times was associated with significantly increased 30-day mortality in ST-elevation myocardial infarction (STEMI) patients, according to a new Canadian study [1]. Patients receiving late reperfusion also had a nonsignificant increase in one-year mortality and a significantly increased risk of the composite of mortality/recurrent MI/ heart failure at one year.

The study, published in the June 2, 2010, issue of the Journal of the American Medical Association, was conducted by a team led by Dr Laurie Lambert (Quebec Healthcare Assessment Agency, Montreal).

Lambert commented to heartwire : "Our conclusions are the same as what the guidelines recommend. But we are providing real-world evidence to back the guidelines up. The guidelines are formulated mainly on the basis of randomized trial data, but the results may be different in the real world. Our study should inspire clinicians to know that they can follow the guidelines and they should be confident that it is the right thing to do in the real-world setting."

She added: "Our main finding is that you should give the reperfusion therapy that you can deliver on time. The guidelines recommend this to be within 90 minutes of presentation at the hospital for primary percutaneous coronary intervention (PCI) and within 30 minutes for fibrinolysis. We found similar results. But what we are saying is that if it is going to take a lot longer than 90 minutes to get the patient to the PCI hospital, then fibrinolysis is an acceptable treatment with good outcomes when done within 30 minutes."

The researchers found that in Quebec, where many patients are transferred from smaller hospitals to the PCI center, median door-to-balloon time for such transfer patients was 123 minutes. Lambert said: "So quite a few patients are well beyond the 90-minute target. It is not always the norm in the real world to measure door-to-balloon times. But I would urge hospitals to measure their process of care and find out what their door-to-balloon times are. And if you are constantly going way over 90 minutes, eligible patients may be better off getting fibrinolysis fast instead. I think our data should persuade more hospitals to think about this."

For their study, Lambert et al analyzed data of STEMI care for six months during 2006–2007 in 80 hospitals in Quebec. Of the 1832 patients treated with acute reperfusion, 78.6% underwent primary PCI and 21.4% received fibrinolytic therapy. Among patients who underwent primary PCI, the median door-to-balloon time was 110 minutes. Primary PCI was untimely (>90 minutes) in 68% of patients. For patients who received fibrinolysis, the median delay was 33 minutes and untimely (>30 minutes) in 54% of patients.
Results showed that the risk of adverse events was similar in patients treated with primary PCI and fibrinolysis but was higher in those treated outside of the maximum recommended delays, regardless of the reperfusion strategy.

The researchers conclude: "Time to reperfusion rather than treatment strategy may be more important in terms of outcomes and can help inform clinical decision making to optimize care for patients."