Predictive value of endothelial function by noninvasive peripheral arterial tonometry for coronary artery disease

BACKGROUND: Endothelial dysfunction is a key step in the initiation and progression of atherosclerosis and subsequent cardiovascular complications. We examined whether peripheral endothelial function, as assessed by fingertip reactive hyperemia-peripheral arterial tonometry (RH-PAT), can provide additional clinical value to traditional risk factors for cardiovascular diseases in predicting coronary artery disease (CAD). METHODS: We included 118 stable patients who were referred for coronary angiography for chest pain evaluation or due to abnormal stress test results. A natural logarithmic value of the RH-PAT index (Ln_RHI) was obtained before cardiac catheterization by an independent operator. Significant CAD was defined as luminal stenosis of at least 70% (≥50% at left main) and/or fractional flow reserve of up to 0.80 in one or more major coronary arteries or their major branches. RESULTS: Levels of Ln_RHI were significantly lower in patients with CAD (n=60) compared with patients without CAD (n=58; 0.69±0.29 vs. 0.88±0.27, P<0.001). Ln_RHI was significantly associated with CAD independent from traditional risk factors (odds ratio for a 0.1 decrease in Ln_RHI=1.25, 95% confidence interval: 1.04-1.52, P=0.01). The net reclassification index was improved when Ln_RHI was added to traditional risk factors (0.62, 95% confidence interval: 0.27-0.97, P=0.001). CONCLUSION: Peripheral endothelial function, as assessed by RH-PAT, improved risk stratification when added to traditional risk factors. RH-PAT is potentially useful for identifying patients at high risk for CAD.