A noninvasive fingertip test can identify patients with the earliest stages of heart disease and may prove cost-effective as a screening test, according to the findings of a Mayo Clinic study published this week in the Journal of American College of Cardiology. “Atherosclerosis tends to affect all of the blood vessels in the body, and is not just limited to the arteries of the heart,” explains Amir Lerman, M.D., the Mayo Clinic cardiologist who led the study. “We expected patients with an abnormal result in the fingertip test to also have disease starting in their coronary arteries. We found a strong correlation, and that the fingertip test was very sensitive in identifying patients with early heart disease.” The study compared results of both invasive and noninvasive tests of dysfunction in a layer of cells called the endothelium that lines the blood vessels. The endothelium protects vessel walls from injury and helps modulate their expansion and contraction to maintain appropriate blood flow and blood pressure. Endothelial dysfunction is the earliest measure of functional abnormality in the blood vessels, so coronary endothelial dysfunction signals the beginning stages of atherosclerosis and heart disease. Researchers are examining how this blood vessel dysfunction in the body’s extremities, such as the fingers, can be a sign that the same problem exists in the heart.