Integrated City-Wide Emergency Protocol Cuts Heart Attack Deaths
People in the Ottawa region who call 911 with chest pain are 50% less likely to die from a heart attack as a result of an advanced emergency protocol developed by the University of Ottawa Heart Institute (UOHI). The program, featured in today's issue of the New England Journal of Medicine, also cuts emergency room congestion and eases critical wait time which directly influences survivability.
Research and trials led by Dr. Michel Le May, Director of UOHI's Coronary Care Unit, have proven that taking a fresh approach to cardiac treatment leads to a significant reduction in mortality. Specifically, the Heart Institute model trains advanced care paramedics to diagnose ST-Elevation Myocardial Infarction (STEMI), a major form of heart attack, and route patients directly to the Heart Institute, bypassing local emergency departments (ED). At UOHI, an emergency STEMI team, available 24/7, administers the type of care proven to be optimal for the survivability of STEMI patients.
"The whole point to this approach is to eliminate time, either time spent in an ED or from the moment an ambulance crew responds to a 911 call to the moment effective treatment is administered," said Dr. Le May. "The longer it takes to receive appropriate care, the greater the risk of damage to the heart and, by extension, the higher the rate of mortality."
Dr. Le May's results in the New England Journal of Medicine (2008; 353:231-40) show that, using the new protocol, in-hospital heart attack deaths between May 2005 and May 2006 dropped to less than 5% for Heart Institute patients, down from 10% for patients who were treated using conventional approaches.
Traditionally, patients experiencing chest pains who arrived at the emergency department were examined by the ED doctor and, in consultation with a cardiologist, the STEMI condition was diagnosed. In the majority of cases, clot-busting drugs (thrombolytics) were administered and the patient's condition subsequently monitored. With this approach, patients requiring "urgent" additional treatment were often transferred to the Heart Institute only after a 2-3 hour delay.
With the new protocol, the ED doctor who detects a STEMI case immediately arranges for an ambulance to route the patient to the Heart Institute. No thrombolytics are employed and no local cardiologist is required. Alternatively, paramedics who respond to a 911 call can also diagnose a STEMI condition and proceed directly to the Heart Institute, bypassing the ED.
In both cases, a "Code STEMI" is triggered and a specialized Heart Institute team is waiting to perform a Percutaneous Coronary Intervention (PCI) or angioplasty. This method involves using a balloon to clear blocked arteries.
In its first full year of using the Heart Institute's new protocol, a total of 344 STEMI patients were transported to the Heart Institute. Of these, 209 were delivered by ambulance from local hospital EDs and 135 were transported directly from the field as a result of 911 calls. The median door-to-balloon time for patients arriving via the ED was 123 minutes and was 69 minutes for those arriving via 911 calls.
In the case of ED routing, about an hour of time was saved with the new protocol compared to previous reports on inter-hospital transfer of patients for PCI. However, by relying on paramedics to diagnose the STEMI, an extremely low door-to-balloon time was achieved. As well, by proceeding directly to the Heart Institute, the paramedics were able to reduce traffic volume to EDs by about 40%.
Other research directed by Dr. Le May has shown that PCI is superior to clot busting drugs in saving heart attack patients. In further findings, inserting a stent by angioplasty to improve blood flow was also much less costly than using a clot busting drug. Overall hospitalization costs were lower. So too was length of stay in hospital.
"The results we have achieved reflect the natural mix of patients who required treatment in a year. This study does not result from highly selected candidates with a specific set of attributes. In other words, they are based on real world conditions and circumstances and involved patients of varying complication and morbidities," said Dr. Le May.
The STEMI program originated with a pilot phase in 2001 by Dr. Le May and colleagues Dr. Justin Maloney, Medical Director of the Ottawa Base Hospital Paramedic Program and Dr. Richard Dionne, Assistant Medical Director of the paramedic program. The STEMI program has drawn interest coast-to-coast in Canada, in the U.S. and Europe.
"This model or any of its parts would work for any city of any size - from training paramedics to identify a STEMI to setting up a system for on-call angioplasty," said Dr. Le May.