NEW YORK (Reuters Health) – Delays in treatment may favor onsite fibrinolytic therapy over transfer for primary percutaneous coronary intervention (PCI) in some patients who present with ST-segment-elevation myocardial intervention (STEMI) to hospitals lacking PCI capability, researchers say.

“While randomized trials support transferring patients for primary PCI over administration of onsite fibrinolysis, in actual practice, delays to implementation are extensive and many patients are not receiving as much benefit as they could in the United States,” Dr. Duane S. Pinto from Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts told Reuters Health in an email.

Dr. Pinto and colleagues evaluated the optimal reperfusion strategy for STEMI patients treated at hospitals that do not perform PCI routinely and where extensive delays resulting from transfer are common. In particular, they examined whether the advantage of transfer PCI (X-PCI, 9506 patients) compared with onsite fibrinolysis (O-FT, 9506 patients) would decline as transfer door-to-balloon door-to-needle (XDB-DN) times increased beyond those encountered in randomized controlled trials. Their findings appear in the November 7th online issue of Circulation.

Among matched patients, survival was similar with X-PCI (4.8%) and O-FT (6.2%), but rates of death/MI and death/MI/stroke were significantly lower with X-PCI than with O-FT.

Delays significantly affected outcomes, though. The mortality benefit of X-PCI over O-FT disappeared with XDB-DN times exceeding 121 minutes (which occurred in 48% of patients), and the endpoint of death/MI/stroke reached equipoise at around 158 minutes.

The magnitude of benefit was greater with X-PCI than with O-FT for patients at least 65 years old, those with longer symptom-onset-to-door time, and patients at higher risk for STEMI.

“Local emergency departments should recognize that the benefit of transferring patients for angioplasty to treat myocardial infarction is time dependent and this benefit erodes very quickly,” Dr. Pinto said. “In some cases, when delays are extensive, fibrinolysis may be an acceptable choice.”

“Transferring patients for PCI is superior to onsite fibrinolysis if performed quickly,” Dr. Pinto said. “Hospitals without PCI capability should continue to strive to improve transportation processes of care and audit the delays that their patients have received so that targeted improvements can be made.”

“As indicated in the ACC/AHA guidelines,” the authors conclude, “the clinician should consider the anticipated PCI-related delay (XDB-DN time) and patient and hospital-based characteristics when selecting a reperfusion strategy.”

Reference:

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

Circulation 7 November 2011.