Endothelial dysfunction is an early sign of coronary artery disease (CAD). This dysfunction may make blood vessels in the fingertips less responsive to changes in blood flow. A simple, noninvasive test of endothelial response in the fingers could help health care providers detect CAD at an early stage, researchers say.

The test, reactive hyperemia peripheral arterial tonometry (RH-PAT), involves placing a probe on a finger of each hand. A blood pressure cuff is applied to one arm; the other arm serves as a control. The cuff is inflated for 5 minutes, then deflated. Measuring changes in blood flow, the probes send information to proprietary software, which quickly analyzes the data and displays the results on a computer screen.

Patients with normal endothelial function experience a definite increase in fingertip blood volume after restoration of blood flow. Those with abnormal endothelial function have a more muted response.

Researchers testing the system studied 94 patients with chest pain who had no evidence of obstructive CAD on coronary angiography. Coronary endothelial function was abnormal in 55 patients and normal in 39 patients. Researchers found that patients with abnormal coronary endothelial function also had abnormal RH-PAT results, compared with those with normal coronary endothelial function. Researchers hope RH-PAT will help practitioners identify and treat CAD at an earlier stage, before atherosclerosis progresses.

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