Benefit of Transferring ST-Segment–Elevation Myocardial Infarction Patients for Percutaneous Coronary Intervention Compared With Administration of Onsite Fibrinolytic Declines as Delays Increase

Study Questions:

What is the clinical impact of delays in transfer for primary percutaneous coronary intervention (PCI) in ST-segment elevation myocardial infarction (STEMI) compared with onsite fibrinolytic therapy in routine clinical practice?

Methods:

The authors assessed the outcome of patients who presented with STEMI within 12 hours of symptom onset and were enrolled in the National Registry of Myocardial Infarction (NRMI). Propensity matching of patients transferred for PCI and treated with onsite fibrinolysis was performed, and the effect of PCI-related delay on in-hospital mortality was assessed. PCI-related delay was calculated by subtracting the door-to-balloon time from the door-to-needle time.

Results:

The study cohort was comprised of 9,506 patients who were transferred for PCI, and were matched with 9,506 patients treated with onsite fibrinolysis. In the matched cohort, PCI was performed with delays >90 minutes in 68%. After adjusting for baseline differences, there was no mortality advantage of transfer for PCI when the door-to-balloon time exceeded the door-to-needle time by 120 minutes. The mortality advantage with PCI was highest when the treatment delay was <60 minutes (2.7% vs. 7.4%), of smaller magnitude with delay of 60-90 minutes (3.6% vs. 5.5%), and absent when the delay exceeded 90 minutes (5.7 % vs. 6.1%). PCI was associated with an advantage for all measured clinical endpoints among patients in the lowest tertile (median, 63 minutes; interquartile range [IQR], 37-78 minutes). Among patients in the second tertile of delay (median, 119 minutes; IQR, 105-136 minutes), there was no survival benefit, but there was a reduction in the composite endpoint of death/MI and death/MI/stroke. Even with prolonged delay (third tertile, median, 208 minutes; IQR, 179-250 minutes), a benefit with respect to stroke was noted with transfer for PCI.

Conclusions:

The authors concluded that transfer for PCI is superior to onsite fibrinolytics, although the survival benefit of PCI diminishes with increasing treatment delay.

Perspective:

This study confirms the superiority of transfer for PCI over onsite fibrinolysis in patients with STEMI. While PCI was superior to, or no different than onsite fibrinolysis, the dramatic survival advantage associated with treatment delays of <60 minutes, invokes the need to develop national systems for rapid triage and transfer of patients presenting to non-PCI hospitals.

Keywords: Myocardial Infarction, Stroke, Fibrinolysis, Percutaneous Coronary Intervention


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