Timeliness of STEMI reperfusion strongly predicts mortality
MedWire News: The timeliness of reperfusion in patients with ST-segment elevation myocardial infarction (STEMI) strongly predicts mortality, irrespective of the reperfusion strategy used, analysis of registry data from Quebec, Canada, shows.
Primary percutaneous coronary intervention (PCI) was the predominant strategy, with most patients transferred from non-PCI hospitals, and delays to reperfusion exceeded maximum recommended delays in a substantial proportion of patients – particularly among those transferred for primary PCI.
Researchers led by Laurie Lambert (Quebec Healthcare Assessment Agency, Montreal) evaluated STEMI care for 6 months during 2006–2007 in 80 hospitals that treated more than 95% of patients with acute MI in the province.
Of 1832 STEMI patients treated with reperfusion, 392 (21.4%) received fibrinolysis and 1440 (78.6%) received primary PCI. Fibrinolysis was untimely (>30 minutes) in 54% of patients compared with primary PCI being untimely (>90 minutes) in 68%.
Death or readmission for acute MI or heart failure at 1 year occurred in 13.5% of fibrinolysis and 13.6% of primary PCI patients.
Analyzing the two treatment groups combined showed that patients treated beyond recommended delays had a significantly increased adjusted risk for death at 30 days (6.6% vs 3.3%, odds ratio [OR]=2.14) and at 1 year (9.3% vs 5.2%, OR=1.61) compared with patients who received timely treatment.
Patients treated outside of recommended delays also had an increased risk for the combined outcome of death or hospital readmission for heart failure or acute MI at 1 year (15.0% vs 9.2%; OR=1.57).
Further analysis showed that, at the regional level, each 10% increase in patients treated within the recommended time was associated with a decrease in the region-level odds of overall 30-day mortality (OR=0.80).
Regional mortality in patients who did not receive reperfusion treatment was no higher in regions where mortality for patients receiving reperfusion treatment was low, suggesting the relationship between reperfusion timeliness and mortality was not due to selective treatment of healthier patients.
The research is published in the Journal of the American Medical Association.
Noting that patients transferred for MI care had a four-fold increased odds of untimely reperfusion in the analysis, Deepak Bhatt (Harvard Medical School, Boston, Massachusetts, USA) noted in a related editorial: “Barring contraindications, prompt fibrinolysis (and transfer to a PCI center) would be preferred in many patients if the alternative is untimely primary PCI.
“Perhaps in aggregate these results support regionalization of care for acute MI, although further research is needed, because the relationships between higher primary PCI volume and better outcome are likely quite complex and may be attenuated if individual hospitals are more adherent to practice guidelines.”
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By Caroline Price