Study Finds Early Marker to Diagnose Heart Attacks

The use of a single blood test that determines heart cell damage can enable physicians to accurately diagnose heart attacks during the first six hours, say researchers at Baylor College of Medicine. Results of the recent study were published in the April 7 issue of Circulation.

"Currently, physicians have the ability to make an accurate diagnosis in only 4 percent of those with chest pain," says Dr. Robert Roberts, chief of cardiology at Baylor and the study's principal investigator.

The test, known as creatine-kinase MB, (CK-MB) subforms, measures the amount of creatine-kinase, an enzyme in skeletal and cardiac muscles, in the blood. According to Dr. Roberts, the enzyme is released through the membranes of dying heart cells, signaling the damaging effects of a heart attack.

Of the more than five million people who visit U.S. emergency rooms with chest pain each year, only 10 percent are actually having heart attacks. Twenty percent suffer from unstable angina, which produces similar symptoms but does not cause permanent damage. An estimated $12 billion is spent each year admitting patients with chest pain to the hospital to determine if they are having a heart attack.

"The use of CK-MB subforms could significantly reduce the number of patients admitted to the hospital unnecessarily, get appropriate and early treatment for heart attacks and unstable angina, and save about $4 to $6 billion a year," says Dr. Roberts, chief of cardiovascular science at The Methodist Hospital.

The multi-center study, which also included The University of Texas-Houston Health Science Center, was designed to compare the five diagnostic markers currently available. Blood samples were taken from patients who arrived in emergency rooms in four Houston hospitals. Samples were also taken one hour later, every two hours up to six hours from onset of chest pain, and then every four hours up to 24 hours.

Of the 955 patients with chest pain, CK-MB confirmed 119 heart attacks and 203 unstable anginas. Only 45 percent of the heart attacks were diagnosed with a standard electrocardiograph.

"The time has come to use early diagnosis so appropriate triage, early therapy and cost-effective, evidence-based medicine can be practiced," Dr. Roberts says.

The study was supported by grants from the Boehringer Mannheim Corporation, Dade International, Helena Laboratories, Spectral Diagnostics, Inc., and the National Heart, Lung and Blood Institute.

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©2006 Texas Medical Center

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