Contact

Duke Health News

919-660-1306

CHICAGO -- In an analysis of more than 185,000 U.S. patients who arrive at emergency rooms with symptoms of a heart attack, Duke University Medical Center researchers have found that those patients whose symptoms and presentation do not appear as immediately acute -- but who in the long-term are actually at higher risk of dying -- do not receive the same aggressive and possibly life-saving therapies.

Just as importantly, the researchers found that all heart attack, or myocardial infarction (MI), patients are not fully receiving therapies that have been proven effective by clinical trials to reduce death and further cardiac events.

At issue are patients who arrive in emergency rooms with symptoms of a heart attack, such as shortness of breath and/or chest pain. Physicians routinely perform an electrocardiogram (ECG) to look for certain telltale patterns that indicate a heart attack. One such portion of the ECG tracing, known as the ST segment, is elevated in the more serious heart attacks.

"Patients with non-ST-segment elevation myocardial infarction (NSTEMI) are treated less aggressively than patients with ST-segment elevation myocardial infarction (STEMI)," said cardiologist Matthew Roe, M.D., of the Duke Clinical Research Institute. Roe presented the results of the study today (April 1, 2003) at the 52nd annual scientific sessions of the American College of Cardiology.

"Typically, emergency room doctors see ST-elevation on the ECG and treat the patient like a trauma case -- very quickly and aggressively," Roe explained. "However, since the NSTEMI patients are usually older, have more vague symptoms, do not report crushing chest pain, and often do not have definite ECG findings on presentation, they usually don?t receive immediate, aggressive care. We now know that these NSTEMI patients should not be overlooked and should be treated just like STEMI patients."

For his analysis, Roe consulted the National Registry of Myocardial Infarction 4 (NRMI-4) registry, which has been collecting data on heart attack patients seen at 1,247 U.S. hospitals since June 2000. Of the 185,968 patients in Roe's analysis, 71 percent of patients were diagnosed with NSTEMI and 29 percent with STEMI. Patients with NSTEMI tended to be older (age 75 vs. 69), more commonly female (45.8 percent vs. 40.4 percent) and more likely to have diabetes (34 percent vs. 26.5 percent) than patients with STEMI.

For Roe, the NRMI-4 data provides one of the clearest views of the current state of heart attack treatment and outcomes in the U.S. "This registry includes all patients with heart attack, unlike most clinical trials that only enroll specific, highly selected types of heart attack patients. NRMI-4 represents the real-world population of patients that cardiologists see every day in their practice."

In terms of mortality in the NRMI-4 database, 12.3 percent of NSTEMI patients died while in hospital, compared with 14.5 percent of STEMI patients. However, Roe pointed out, past studies have demonstrated that the 6-month mortality rate for NSTEMI patients is actually higher than for STEMI patients since these patients are more likely to die after hospital discharge

"Since NSTEMI patients have worse long-term mortality and make up such a large percentage of the total heart attack population, they should be treated just as aggressively as STEMI patients," Roe said.

For example, Roe examined the incidence of administration of three drugs whose benefit has been proven when given within 24 hours of a heart attack -- aspirin, heparin and beta-blockers. He found that while all patients who could benefit from the medications did not get them, the NSTEMI patients were less likely to get them.

Specifically, 84.9 percent of NSTEMI patients received aspirin (compared to 88 for STEMI patients); 72.6 percent heparin (84.2 percent for STEMI patients); and 72.2 percent beta-blockers (77.8 percent for STEMI patients).

This disparity in treatment while in the hospital also extended to treatments given to patients at discharge to reduce the risks of future events.

The NSTEMI patients received significantly less aspirin (83.8 percent vs. 88.9 percent); beta-blockers (78.3 percent vs. 83.4 percent); ACE inhibitors (51.2 percent vs. 58 percent); and lipid-lowering agents (85.7 percent vs. 86.7 percent) at discharge.

It is estimated that about 715,000 Americans experience NSTEMI or unstable angina each year.

Roe said that this study demonstrates the importance of programs such as the NRMI-4, which routinely feeds back treatment patterns to health care providers and raises awareness regarding the "real-world" care of heart attack patients. He added that the gap between guidelines recommendations and actual care is also a strong argument for programs such as the American Heart Association?s "Get With The GuidelinesTM program" and the CRUSADE National Quality Improvement Program, whose aims are to disseminate clinical practice guidelines and encourage adherence to guidelines through pro-active quality improvement interventions.

The NRMI-4 database is supported by Genentech, South San Francisco, Calif.