Overuse of Cardiac Testing

Cardiovascular disease is the leading cause of death worldwide. More than 25% of individuals who experience acute myocardial infarction have no previous symptoms, making risk stratification essential to help target appropriate preventive interventions. Risk stratification should be performed using a clinical assessment of risk factors and exercise tolerance, as well as a validated risk tool. Inappropriate use of diagnostic tests to screen for cardiac disease in asymptomatic patients may lead to further testing and invasive procedures that are costly and potentially harmful, and have no clear benefits compared with clinical history and evaluation alone.

Routine screening of asymptomatic patients with ECG has a very low yield in detecting significant pathology and leads to many false-positive findings. Performing ECG as part of a health maintenance examination does not lower the risk of future cardiovascular events or cardiac death. The U.S. Preventive Services Task Force (USPSTF) recommends against screening with ECG to predict CAD in low-risk patients and found insufficient evidence to assess the benefits and harms of screening in individuals at intermediate or high risk.

Stress ECG (exercise stress tests), stress echocardiography, and myocardial perfusion imaging are commonly used to evaluate patients for CAD. However, it is unclear if these tests add any prognostic benefit beyond a careful evaluation of underlying cardiovascular risk factors in patients without cardiac symptoms. Inappropriate cardiac stress tests, particularly when done with imaging, are estimated to cost the U.S. health care system as much as half a billion dollars each year and expose many patients to unnecessary radiation.

It is important to understand that stress testing detects only significant coronary stenosis and does not identify nonobstructing plaques, which are a common cause of myocardial infarctions. In fact, because many patients who present with an acute myocardial infarction have no prior obstructive CAD, normal results on a stress test might be falsely reassuring. On the other hand, in a patient with a low pretest probability of CAD, a positive stress test is likely to be a false positive.

Many persons with a false-positive result on stress testing undergo subsequent testing and interventions such as cardiac catheterization and revascularization. Up to 3% of persons who get stress tests undergo cardiac catheterization, and 1.7% of catheterizations lead to severe adverse reactions, mostly in persons without CAD. Screening for CAD with stress tests has not been shown to affect clinical outcomes or further inform the use of risk-reducing therapies beyond a good clinical assessment.