Feature: Fibrinolysis for transferred STEMIs produces good outcomes
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“ST-elevation myocardial infarction [STEMI] patients who present to geographically isolated hospitals located long distances from a primary PCI-capable hospital frequently have delays to PCI of more than120 minutes,” according to background material from the study.
“While we know that primary PCI is usually the preferred method for STEMI patients when they are done within 90 minutes door-to-balloon (D2B) time, the problem is that there are many patients who live too far away in rural areas," David M. Larson, MD, of the Minneapolis Heart Institute Foundation at Abbott Northwestern Hospital and lead author of the study told Cardiovascular Business in an interview. He is also chair of the department of emergency medicine and medical director of the Chest Pain Center at the Ridgeview Medical Center in Waconia, Minn. The recommended European D2B time is 120 minutes.
"For those patients in rural areas, the other alternative is administering a fibrinolytic,” he said. However, patients don’t normally do as well with fibrinolytics, because only 55 percent of patients reperfuse, Larson noted.
During the current study, the researchers enrolled 2,634 STEMI patients. Of the patient cohort, 600 presented to the PCI hospital (Minneapolis Heart Institute-Abbott Northwestern Hospital), 1,195 patients presented to Zone 1 hospitals that were less than 60 miles away and 839 patients presented to Zone 2 hospitals that were located more than 60 miles away from the primary PCI hospital.
Within the 31 referral hospital network, Abbott Northwestern Hospital is the primary PCI hospital. Since 2003, Abbott Northwestern implemented a protocol that administers half-dose fibrinolytic therapy (usually t-PA) to patients who live 60 miles away or more who could not reach D2B times of less than 90 minutes and then be transferred directly to the cath lab.
For a reperfusion strategy, 73.7 percent of patients underwent primary PCI (1,163 patients from Zone 1 hospitals and 170 patients from Zone 2 hospitals), while 26.4 percent of patients received a half-dose fibrinolysis (660 patients from Zone 2 hospitals and 32 patients from Zone 1 hospitals).
Larson et al compared primary-PCI treated patients who presented directly to a PCI hospital or were transferred from Zone 1 hospitals with the pharmaco-invasive PCI-treated patients transferred from Zone 1 or 2 hospitals.
The authors reported median D2B times to be 62 minutes for patients who presented directly to the PCI hospital, 94 minutes for primary PCI patients who were transferred to Zone 1 hospitals and 122 minutes for pharmaco-invasive-treated patients transferred from Zone 2 hospitals. Door-to-needle times were 29 minutes for patients receiving fibrinolytic therapy prior to transfer.
Larson said that taking a patient to do an angioplasty too soon after they have received fibrinolytic therapy could cause platelet activation and the patient could see more bleeds. “However, we have shown that it is safe to transfer the patient to the cath lab as soon as possible,” Larson said. During the trial, patients received PCI within 60 and 120 minutes after they received fibrinolytics.
“We have shown that patients can have the exact same outcomes whether they live 200 miles away from a primary PCI center of just down the street from a primary PCI hospital with this regiment,” Larson noted. “Patients had the same mortality, same safety and same amount of major bleeding. All the adverse cardiac events were the same.”
In sum, Larson said that the study results showed that disparities between outcomes in rural settings and urban settings can be eliminated. “This establishes that this is a very successful protocol for those who live in rural areas who live long distances from the cardiac cath lab not only in the U.S. but also internationally," he said.