Image: A rapid diagnostic test for determination of elevated CK-MB levels in blood, which some scientists suggest may be unnecessary (Photo courtesy of Response Biomedical).
Heart disease remains the leading cause of death in men and women in the USA, and each year 735,000 Americans have heart attacks that damage the heart muscle, and of those, an estimated 120,000 die.
About one in five heart attacks are "silent," yielding no symptoms, but symptoms such as chest tightness or pain, dizziness, nausea and fatigue are good reasons to seek immediate evaluation. Among the diagnostic tools to detect heart attacks are blood tests that measure levels of various proteins released into the bloodstream when heart cells are injured. Two of these are cardiac troponin and creatine kinase-myocardial band (CK-MB).
Scientists at the Johns Hopkins University School of Medicine (Baltimore, MD, USA) and the Mayo Clinic (Rochester, MN, USA) have compiled peer-reviewed evidence and crafted a guideline designed to help physicians and medical centers stop the use of a widely ordered blood test that adds no value in evaluating patients with suspected heart attack.
The clinical and financial implications of institutions continuing CK-MB testing are significant, say the authors, who estimate that all blood tests for diagnosing heart attacks add USD 416 million each year to the cost of care. The team also cites studies showing that in addition to its diagnostic value, troponin testing is a more definitive predictor of in-hospital mortality and severity of disease. Professional guidelines concluded that CK-MB provides no additional diagnostic value for diagnosing heart attacks. It was found that 77% of nearly 2,000 laboratories in the U.S. still use CK-MB as a cardiac damage biomarker.
Jeffrey Trost, MD, an assistant professor of medicine and the corresponding author of the study, said, “This article is the first in a series of collaborative multi-institutional publications designed to bridge knowledge to high value practice. We present multiple quality improvement initiatives that safely eliminated CK-MB to give providers reassurance about trusting troponin levels when managing patients with suspected acute coronary syndrome.” The study was published on August 14, 2017, in the journal JAMA Internal Medicine.
Johns Hopkins University School of Medicine