Noninvasive identification of patients with early coronary atherosclerosis by assessment of digital reactive hyperemia

We investigated the value of reactive hyperemia peripheral arterial tonometry (RH-PAT) as a noninvasive tool to identify individuals with coronary microvascular endothelial dysfunction. Coronary endothelial dysfunction, a systemic disorder, represents an early stage of atherosclerosis; RH-PAT is a technique to assess peripheral microvascular endothelial function. Using RH-PAT, digital pulse volume changes during reactive hyperemia were assessed in 94 patients without obstructive coronary artery disease and either normal (n = 39) or abnormal (n = 55) coronary microvascular endothelial function; RH-PAT index, a measure of reactive hyperemia, was calculated as the ratio of the digital pulse volume during reactive hyperemia divided by that at baseline. Average RH-PAT index was lower in patients with coronary endothelial dysfunction compared with those with normal coronary endothelial function (1.27 ± 0.05 vs. 1.78 ± 0.08: p < 0.001). An RH-PAT index <1.35 was found to have a sensitivity of 80% and a specificity of 85% to identify patients with coronary endothelial dysfunction. Digital hyperemic response, as measured by RH-PAT, is attenuated in patients with coronary microvascular endothelial dysfunction, suggesting a role for RH-PAT as a noninvasive test to identify patients with this disorder.