Cardiac Problems More Often Missed in Young Women and Minorities

A large study conducted at 10 participating hospitals in the US found that younger women, minorities and patients without chest pain or diagnostic EKGs were more likely to be sent home from emergency departments with missed diagnoses of heart attacks or unstable angina pectoris.

"This study has identified important areas for improvement, including a profile of a patient that is at high risk for missed diagnosis," says Tom P. Aufderheide, MD, Professor of Emergency Medicine at the Medical College of Wisconsin. Dr Aufderheide was co-investigator in the study, published in the April 20 issue of The New England Journal of Medicine. Harry Selker, MD, of the New England Medical Center, and Professor of Medicine at Tufts University School of Medicine in Boston, was the principal investigator.

Each year in the US, 7 million patients go to hospital emergency departments with chest pain or other symptoms suggesting a cardiac problem. Although many will prove not to need hospitalization, for the 20% who have acute cardiac ischemia (i.e., either heart attack or unstable angina pectoris, which can lead to heart attack), mistakenly not being hospitalized could be life threatening.

To determine how often emergency patients with acute cardiac ischemia are mistakenly sent home, and to understand the contributing factors, researchers analyzed care in the national 10,689-patient ACI-TIPI (acute cardiac ischemia time-insensitive predictive instrument) Trial, the largest study of emergency department triage decision-making ever conducted. Because the study reevaluated more than 99% of all discharged patients within 24 to 72 hours after initial presentation, the reliable detection of missed diagnosis was possible.

The study was conducted at Froedtert Hospital and 9 other hospitals throughout the United States. Over 1,300 patients were seen at Froedtert Hospital. Combining the data from all 10 hospitals, the study found that 2.1% of patients with heart attack, and 2.3% of patients with unstable angina, were mistakenly sent home. With seven million patients presenting to emergency department with chest pain each year in this country, this means that 26,000 emergency department (ED) patients with acute cardiac ischemia are mistakenly not hospitalized: 12,000 with heart attacks and 14,000 with unstable angina.

Failure to hospitalize patients with acute cardiac ischemia was more likely if the patient was non-white (2.2 times more likely, and 4.5 times more likely if having a heart attack), a woman under age 55 (6.7 times more likely), had a primary symptom of shortness of breath rather than chest pain (2.7 times more likely), or had a normal or a non-diagnostic electrocardiogram (EKG) (3.3 times more likely, and 7.7 times more likely if having a heart attack).

Moreover, these failures to hospitalize showed a statistical trend for greater mortality: non-hospitalized patients with heart attack were 1.9 times more likely to die than similar patients who were hospitalized, and non-hospitalized patients with unstable angina were 1.7 times more likely to die than similar patients who were hospitalized.

This is one of a series of national and international studies of the ED care of patients with potential cardiac symptoms done by the ACI-TIPI Investigators, based at New England Medical Center's Center for Cardiovascular Health Services Research, sponsored by the Agency for Healthcare Research and Quality. In the original report of this study, these researchers showed that the ACI-TIPI electrocardiograph, which prints an ED patient's true probability of acute cardiac ischemia on their EKG, improved physicians' ED decision-making.

Dr. Aufderheide said that since the study was performed the Department of Emergency Medicine at Froedtert Hospital has implemented new diagnostic testing, continuous 12-lead EKG monitoring, a chest pain observation unit and expanded the availability of cardiac stress testing. "The results of this study should assist hospitals throughout the US to identify high risk patients, to optimally utilize new diagnostic testing, and improve the standard of care nationally."

MCW Health News presents up-to-date information on patient care and medical research by the physicians of the Medical College of Wisconsin.