Registry Finds Prehospital Fibrinolysis Suitable for Low-Risk STEMI Patients

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Under the right circumstances, prehospital fibrinolysis followed by early invasive evaluation provides lower 1-year mortality than primary percutaneous coronary intervention (PCI) for patients with ST-segment elevation myocardial infarction (STEMI). Findings from a Finnish registry were published online August 21, 2013, ahead of print in the European Heart Journal: Acute Cardiovascular Care.

Juho Viikilä, MD, of Helsinki University Central Hospital (Helsinki, Finland), and colleagues compared outcomes among 448 patients in the Helsinki-Uusimaa Hospital District registry of ST-Elevation Acute Myocardial Infarction (HUS-STEMI) who received primary PCI (n = 194), prehospital fibrinolysis followed by early invasive evaluation (n = 176), or no reperfusion treatment within 12 hours (n = 78). Patients were treated during a 1-year period starting in June 2007.

Age, gender, cardiovascular risk factors, and prior CAD were similar among all 3 groups. However, fibrinolysis-treated patients were less likely to have prior stroke (P = 0.02) and had lower median TIMI risk scores compared with those receiving either primary PCI or no reperfusion (P < 0.001). Notably, 31% of the fibrinolysis group underwent rescue PCI, with 69% ultimately receiving PCI during the index hospitalization.

Median time from symptom onset to diagnostic ECG was 115 minutes for primary PCI, 53 minutes for fibrinolysis, and 591 minutes for no reperfusion, while the median time from symptom onset to the start of reperfusion was 240 minutes for primary PCI and 90 minutes for fibrinolysis (P < 0.001 for both).

Higher Mortality for Primary PCI at 1 Year

Mortality trended higher for primary PCI compared with fibrinolysis at 30 days, with the difference becoming significant at 1 year. MACE (CV death, stroke, reinfarction, and repeat revascularization) and CV death alone were equivalent at 1 year, and in-hospital bleeding rates were similar between the 2 groups (table 1). In the no reperfusion group, mortality was 9.0% at 30 days and 13% at 1 year.

Table 1. Outcomes by Treatment Group

^a Adjusted for differences in age, sex, diabetes, renal function, previous ACS, previous CHF, Killip class, and presentation delay.

Among the 304 patients who presented within 3 hours of symptoms, median delay from symptom onset to start of reperfusion was still longer for primary PCI than for fibrinolysis at 178 vs. 90 minutes (P < 0.01). The differences between primary PCI and fibrinolysis were significant for 30-day mortality (9.3% vs. 3.7%; adjusted P = 0.045), 1-year mortality 15.3% vs. 3.7%; adjusted P = 0.001) and 1-year CV death (10% vs. 3.7%; adjusted P = 0.037).

Role for Fibrinolysis When Timely PCI Not Available

“Our results support the idea that [fibrinolysis] followed by early invasive evaluation represents an effective treatment strategy for a considerable proportion of STEMI patients,” Dr. Viikilä and colleagues conclude, acknowledging that “local STEMI treatment guidelines resulted in an imbalance in delays and acute risk between the reperfusion groups. Therefore, the comparisons between the treatment strategies are likely to be biased and cannot be interpreted as showing [overall] superiority of [fibrinolysis] over [primary PCI].”

In an e-mail communication with TCTMD, Morton J. Kern, MD, of the University of California, Irvine (Irvine, CA), described the study as “provocative, . . . counterintuitive, and contrary to prior data where primary PCI was better than fibrinolysis for outcomes. The patients were a preselected lower STEMI risk group but nonetheless had lower mortality.” The findings, he said, “should lead to a larger US trial, but systems are now geared for primary PCI so change of patterns will be a challenge.”

However, he noted that LV function was not measured so differences in outcomes could arise from worse clinical presentation or infarct size in the primary PCI group.

Philippe Généreux, MD, of Columbia University Medical Center (New York, NY), also expressed concerns. “The main problem is that there are several differences among groups that influence outcome,” he noted to TCTMD in a telephone interview, citing ischemic time in particular. “We have to be careful with the interpretation of this highly biased registry, which is obviously not randomized.”

Fibrinolysis has a place for “low-risk patients treated in a real-life setting where you don’t have access to primary PCI,” Dr. Généreux agreed, but pointed out that fibrinolysis as it is currently performed carries a higher risk of intracranial bleeding “which is not trivial.” Moreover, as primary PCI improves, “the dogma of door-to-balloon times [being fixed at 90 minutes] is about to change, so that there’s a paradigm shift” away from fibrinolysis, he commented.

 

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Source:
Viikilä J, Lilleberg J, Tierala I, et al. Outcome up to one year following different reperfusion strategies in acute ST-segment elevation myocardial infarction: The Helsinki-Uusimaa Hospital District registry of ST-Elevation Acute Myocardial Infarction (HUS-STEMI). Eur Heart J: Acute Cardiovasc Care. 2013;Epub ahead of print.

 

 

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