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12-03-2013 | Cardiology | Article

Prehospital fibrinolysis benefits some myocardial infarction patients


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medwireNews: Prehospital fibrinolysis may be a substitute reperfusion strategy in patients with ST-segment elevation myocardial infarction (STEMI) if prompt percutaneous coronary intervention (PCI) is not possible, research shows.

As reported in The New England Journal of Medicine, Frans Van de Werf (KU Leuven, Belgium) and colleagues found that clinical outcomes were similar in 1892 patients with STEMI who had presented too late to undergo PCI within the ideal 1-hour time window if they received either PCI or prehospital fibrinolysis (tenecteplase plus antiplatelet and anticoagulant therapy) with later coronary angiography. Most patients in the fibrinolysis group underwent angiography a median of 17 hours after randomization; however, 36.3% required emergency angiography because of failure of fibrinolysis.

The primary composite endpoint of the randomized Strategic Reperfusion Early after Myocardial Infarction (STREAM) trial comprised death, shock, congestive heart failure, or reinfarction within 30 days. This occurred in 12.4% of patients given fibrinolysis and 14.3% of those assigned to PCI, giving a nonsignificant 14% reduced risk with fibrinolysis.

The team says this falls within "generally accepted" proportional margins for noninferiority, making fibrinolysis an "effective" reperfusion strategy for patients who cannot undergo PCI within 1 hour.

The rate of intracranial bleeding was increased fivefold among patients in the fibrinolysis group, although rates were very low overall, at 1.0% and 0.2% in the fibrinolysis and PCI groups, respectively.

The increased rate of intracranial bleeding in the fibrinolysis group was confined largely to patients aged 75 years or older, prompting the investigators to halve the dose of tenecteplase in that age group. After this adjustment, the intracranial bleeding rate was 0.5% and 0.3% in the fibrinolysis and PCI groups, respectively.

In an accompanying editorial, Deepak Bhatt (Brigham and Women's Hospital, Boston, Massachusetts, USA), says: "This is an appealing interpretation of the data, since it would make the care of patients with STEMI much easier at sites that cannot perform prompt PCI.

"However, the lack of superiority of the fibrinolysis approach coupled with the increased rate of intracranial hemorrhage would seem to make this an inferior strategy, as compared with the alternative of striving to design systems that allow patients to receive rapid PCI uniformly."

Bhatt notes that the "logical approach to using half-dose fibrinolysis in older patients would need further prospective validation before such a strategy should be widely recommended." And he adds that "since the start of the STREAM trial, the results of primary PCI have gotten better and safer, creating an even higher bar for prehospital fibrinolysis."

By Eleanor McDermid, Senior medwireNews Reporter

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