STEMI Networks: Not Why, But How

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Reperfusion is the preferred strategy for patients presenting with ST-segment elevation MI (STEMI) and outcomes improve with regionalized systems of care. Yet, such systems are not all equal and competition for patients within regionalized care can impede their initiation and effectiveness.

To begin at the beginning

STEMI patients in the U.S. number about 400,000 each year—representing about one-third of MI sufferers. The American College of Cardiology’s (ACC) Door-to-Balloon (D2B) Alliance proposed a target in 2006 that more than 75 percent of U.S. providers achieve D2B times of 90 minutes, whereas the baseline rate across the U.S. was less than 40 percent. While sending a prehospital ECG to the ED has proved to help reduce D2B times during emergent PCI for patients with STEMI, its utilization was less than 10 percent, according to National Registry of MI data from 2000 to 2002 (J Am Coll Cardiol 2006;47:1544-1552).

More recently, STEMI-receiving center networks have demonstrated that the use of prehospital ECGs results in dramatic improvement in the rate of timely reperfusion. Rokos et al found that 10 independent STEMI networks—across disparate regions in the U.S.— demonstrated a combined 86 percent rate of D2B of 90 minutes or less (J Am Coll Cardiol Intv 2009;2:339-346).

Empowering emergency medical services (EMS) is one of the first steps in forming an effective STEMI regional network. “EMS is the gateway for medical services,” says Christopher B. Granger, MD, director of the cardiac care unit at Duke University School of Medicine in Durham, N.C. “By engaging EMS when designing a system of care, the hospitals are forced to become engaged.”

For instance, to improve Tennessee’s quality of cardiac care, the Tennessee Cardiac Systems of Care Task Force has been “actively involved” with the American Heart Association’s (AHA) Mission: Lifeline to establish a STEMI system of care for the Greater Nashville region, explains David Chambers, MD, a cardiologist at Horizon Medical Center in Dickson, Tenn., who is chairman of the task force. Mission: Lifeline has been assisting the task force with establishing processes and funding. Tennessee recently ranked 48 out of 50 states in cardiovascular mortality.

To improve STEMI care across Tennessee, the task force is meeting with various EMS representatives to enhance prehospital 12-lead ECG capabilities in the ambulatory setting, says Chambers, who serves as medical director for Dickson County EMS. “The task force also is assessing protocols for paramedics to perform a 12-lead ECG, diagnose a STEMI and activate the cath lab at the designated STEMI center.”

“The creation of formal destination protocols by regional authorities allows EMS providers to bypass facilities without cath labs when they have identified a STEMI patient,” says Ivan C. Rokos, MD, from the UCLA Olive View department of emergency medicine in Los Angeles, who also is the AHA’s chair of the Western STEMI Task Force. The task force is seeking to regionalize STEMI care for all of California and nine Western states.

Granger adds, “When developing these networks, a manual of standardized protocols is needed for each point of STEMI care—starting with EMS through the ED through cath lab activation—which should seek to establish best practices at each point in the patient care continuum.”

Inter-hospital transfer

In Los Angeles County, there are 75 paramedic-receiving hospitals, serving 10 million people—30 of which are designated STEMI centers. Although the remaining 45 hospitals do not have cath lab capabilities for primary PCI interventions, some are now active STEMI referral facilities. After two years of planning and a price tag of $7 million, Los Angeles County commenced its prehospital cardiac triage process in December 2006.
“While the establishment of appropriate prehospital triage protocols was relatively seamless, inter-hospital transfers to STEMI centers have caused more challenges,” says Rokos. This is particularly important because 50 percent of STEMI patients in the U.S. do not utilize EMS.

Therefore, Los Angeles County established a “rapid and reliable transfer option using 9-1-1 providers. If a patient presents at a hospital without a cath lab, the ED staff can call 9-1-1 to have EMS providers transfer the STEMI patient to a STEMI receiving center,” he says.

While this may seem contrary to the bottom line of the referring hospital, Rokos suggests that providers are “unlikely to gain or lose