SAN FRANCISCO—Prehospital fibrinolysis in STEMI patients who present shortly after symptom onset and who cannot undergo PCI within the first hour appears to be as effective as primary PCI, based on STREAM results presented March 10 at the American College of Cardiology (ACC) scientific session. The results are likely to influence practice, according to panelists who commented on the findings.
STREAM (Strategic Reperfusion Early After Myocardial Infarction) findings simultaneously were published online in the New England Journal of Medicine.
Contemporary guidelines recommend PCI as the first-line treatment for patients who present with STEMI. International registries show there are “persisting delays” in primary PCI for STEMI patients who present to community hospitals that lack cath labs, said Frans Van de Werf, MD, PhD, chairman of the cardiovascular department at the University Hospitals in Leuven, Belgium.
This presents a challenge for physicians treating these patients. STREAM was designed as a proof-of-concept study to compare outcomes in such patients treated with a fibrinolytic strategy or primary PCI. Van de Werf emphasized that the analyses were exploratory.
The study enrolled 1,915 patients from 15 countries between 2008 and 2012, of whom 1,892 were randomized to either primary PCI or a fibrinolysis therapy with bolus tenecteplase, clopidogrel (Plavix, Bristol-Myers Squibb) and enoxaparin coupled with coronary angiography. To be eligible, patients had to have presented within three hours after the onset of symptoms and were unable to undergo PCI within one hour.
“This was a typical STEMI population,” he said.
Physicians performed rescue coronary intervention if fibrinolysis therapy failed. Otherwise, patients were transferred to a PCI-capable hospital to undergo PCI. The primary endpoint was 30-day composite of death from any cause, shock, congestive heart failure or reinfarction.
“Initially, there was a problem,” when excess intracranial hemorrhage was observed in older participants, Van de Werf acknowledged. In 2009, the protocol was amended to reduce the dose of tenecteplase by half in patients older than 75 years.
Baseline characteristics in both groups were generally similar.
The primary endpoint occurred in 12.4 percent of the fibrinolysis group vs. 14.3 percent of the PCI group. In the fibrinolysis group, 36.3 percent required emergency angiography. Of those who did not need rescue coronary intervention, PCI was performed at a median 17 hours after randomization.
“Procedures were equally effective in both groups,” Van de Werf said.
Cardiogenic shock and congestive heart failure occurred more often in the primary PCI group and intracranial hemorrhage and ischemic strokes were more frequent in the fibrinolysis group. Before the tenecteplase dose was reduced in older patients, 8.6 percent of these patients experienced intracranial hemorrhage, and none after the protocol change. The rates of nonintracranial bleeding and blood transfusions were similar in both groups.
After the protocol change, there were no significant differences in stroke rates, he said.
Timely prehospitalization treatment for patients in remote locations “circumvents the need for urgent procedures in about two-thirds of fibrinolytic-treated STEMI patients, was associated with a small increase in intracranial bleeding but seems to be as effective as primary PCI,” he concluded.
Panelist Freek W. A. Verheugt, a professor of cardiology at Onze Lieve Vrouwe Gasthuis in Amsterdam, described the finding that two-thirds of patients did not need urgent intervention as good news. While he did not foresee the findings leading to guideline changes, “I think it will change practices in some parts of the world,” he said.
George D. Dangas, MD, director of cardiovascular innovation, Mount Sinai Medical Center in New York City, also highlighted safety lessons from the study. “The message [is] that patients over 75 years or under 60 kilograms of body weight may need different treatment or perhaps faster transfer to the PCI center,” he said.
Boehringer Ingelheim funded the study.