Does EMS Activation of Heart Catheterization Labs Have an Impact on D2B Times?

Coronary artery disease is the leading cause of death in the United States, with myocardial infarction being a common manifestation of this disease process. ST-elevation myocardial infarction (STEMI), which is characterized by a complete blockage of a coronary artery, is considered the most serious and deadly type of heart attack. It is clinically diagnosed through signs and symptoms, ECG interpretation and heart catheterization. Rapid response and treatment are required to open the artery and restore patent blood flow to the heart muscle.

For patients with ST-elevation myocardial infarction, each passing minute equals more heart muscle damage. Of those experiencing myocardial infarctions, 25% to 30% will die before receiving medical attention, most of them from the arrhythmia known as ventricular fibrillation.

Studies have shown that prompt percutaneous coronary intervention (PCI) for STEMI patients significantly reduces their morbidity and mortality, and that STEMI patients have better outcomes if they receive PCI within 90 minutes of arrival to hospitals. However, even in hospitals with catheterization labs, only 40% of STEMI patients receive intervention within the 90-minute door-to-balloon (D2B) time recommended by the American Heart Association and American College of Cardiology. The data most recently published by the National Registries of Myocardial Infarction states that only 20% of STEMI patients in the U.S. are treated with PCI. Delays in treating or misdiagnosis of such a fatal type of heart attack can result in catastrophic heart damage and death.

EMS plays an important role in the care delivered to patients with STEMIs or other MIs. EMS involvement in the diagnosis of STEMIs and activation of catheterization labs has been shown to decrease patients' D2B times and improve their outcomes. Some EMS crews now have the capacity to transmit electrocardiograms from call scenes directly to emergency departments for ED physicians and cardiologists to read, allowing them to activate cath labs if necessary. Due to the importance of prehospital ECGs and the vital role EMS plays in positive STEMI patient outcomes, this article will examine whether the role EMS plays is truly vital to D2B times.

Statement of the Problem

A survey by the American Heart Association, one of the largest national surveys of EMS systems to date, indicated a need for improvements in the way MI patients, specifically STEMI patients, are treated and managed. The survey, conducted between October and December 2008, questioned more than 5,400 EMS systems regarding staffing, funding, training and existing processes for managing STEMI patients. The most significant findings were as follows:

• Only 50% of systems surveyed had 12-lead ECG capabilities, used in detecting STEMIs, on 75% or more of their vehicles.
• Of systems with 12-lead capabilities, most lacked standard methods for EMS to transmit or communicate the results to receiving hospitals.
• EMS remotely activated hospitals' catheterization labs only 40% of the time.
• Only 20% of hospitals were capable of performing procedures such as angioplasty for STEMI patients 24 hours a day, 7 days a week.
• Minimal initiation and use of current protocols.

Other findings were that information-sharing between EMS and receiving hospitals was poor, and that more paramedics should receive education and training in interpretation of ECGs.

EMS Magazine's October 2006 issue featured an article discussing out-of-hospital STEMI alert processes and protocols and what objectives must be met before a system/protocol is reliable for STEMI patients. First and foremost, it concluded, a mandate needed to be set by both service medical directors and operations chiefs for any alert process to be successful. EMS administrators, like other administrators, focus on the financial bottom line. Those administrators need to be aware that, currently, "performance of 12-lead ECGs and aggressive management of patients with STEMI is an unfunded mandate, since Medicare bundles those costs into its ALS base rate--i.e., there is no 'pay for performance' incentive." In addition, EMS personnel felt they must be familiar with current EMS literature regarding STEMI guidelines, recommendations and processes, and be in line with processes set forth by hospitals. Communication between EMS and hospital staff regarding current protocols and practices is vital for proper care and management of STEMI patients.