Strategies for the Emergency Room Evaluation of Patients with Chest Pain

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The summary below is from the full report titled "Emergency Department Triage Strategies for Acute Chest Pain Using Creatine Kinase-MB and Troponin I Assays: A Cost-Effectiveness Analysis." It is in the 12 December 1999 issue of Annals of Internal Medicine (volume 131, pages 909-919). The authors are C.A. Polanczyk, K.M. Kuntz, D.B. Sacks, P.A. Johnson, and T.H. Lee.

What is the problem and what is known about it so far?

Doctors do not want to send home from the emergency room patients with chest pain who are having heart attacks. On the other hand, hospitalizing everyone with chest pain would lead to a great many unnecessary hospital stays. Several kinds of tests can help doctors decide whether someone with chest pain has actually had a heart attack. For example, blood tests are used to look for substances such as CK-MB (an enzyme) or troponin I (a muscle-pump protein) that leak into the bloodstream from damaged heart muscle. Electrocardiograms (EKGs) and stress (exercise) tests can also help. The best overall way to evaluate patients with chest pain in emergency rooms is not clear, however.

Why did the researchers do this particular study?

The researchers wanted to find out which combination of tests for evaluating patients with chest pain saved the most lives at the most reasonable costs.

Who was studied?

Answering the study question by using actual patients would require studying many patients, with many different combinations of tests, over several years. Instead, the researchers used computers to describe what would happen to a "virtual" group of 50- to 74 year-old patients who came to an emergency room with chest pain.

How was the study done?

The authors looked at studies that used actual patients to find information about what might happen when each diagnostic approach is used separately. They looked to see how much various combined approaches would cost for each additional year of life they save.

What did the researchers find?

No single strategy was best for all patients. For 50- to 64-year-old patients, a CK-MB test followed by exercise testing was the best strategy, costing about $43,000 per year of life saved. For 65- to 74-year-old patients, a CK-MB test followed by troponin I testing cost about $47,400 per year of life saved. This test was the most reasonable strategy when early stress tests could not be done, when CK-MB levels were normal, and when the electrocardiogram indicated low blood flow to the heart.

What were the limitations of the study?

Because this study was a computer simulation, we cannot be sure what the results would be with actual patients. However, these estimates can be useful because studies using actual patients are unlikely to be done anytime soon (if ever). The findings may not apply to patients younger than 50 years of age or older than 74 years of age.

What are the implications of the study?

Testing for CK-MB followed by early stress testing appears to be the best way to evaluate 50- to 64-year-old patients who come to the emergency room with chest pain. Troponin I may be a reasonable second test in some patients, such as those older than 64 years of age, particularly under certain conditions.