Impaired Digital Reactive Hyperemia and the Risk of Restenosis after Primary Coronary Intervention in Patients with Acute Coronary Syndrome

Aim: Reactive hyperemia peripheral arterial tonometry (RH-PAT) can be used to noninvasively assess the vascular function with respect to the digital microcirculation. Abnormalities are associated with coronary endothelial dysfunction. We therefore investigated whether impaired digital reactive hyperemia is associated with restenosis after percutaneous coronary intervention (PCI) in patients with acute coronary syndrome (ACS). Methods: This study included 86 patients with ACS who underwent successful primary PCI of native vessels for de novo lesions. The reactive hyperemia index (RHI) was calculated using RH-PAT at three weeks and eight months after ACS. The RHI was defined as the ratio of the digital pulse volume during reactive hyperemia to that observed at baseline. Restenosis was defined as diameter stenosis of >= 50% in the in-segment area based on the findings of quantitative coronary angiography performed at eight months. Results: Restenosis was detected in 17 patients (20%). There were no differences in the RHI at three weeks between the patients with and without restenosis (1.70 vs. 1.87; p = 0.13); however, the RHI values at eight months were significantly attenuated in the patients with restenosis versus those without (1.75 vs. 2.12; p = 0.03). A univariate logistic regression analysis showed that the eight-month RHI (<2, obtained from a receiver operating characteristic analysis) was a significant risk factor for restenosis (odds ratio: 4.23, 95% confidence interval: 1.25 to 14.28, p = 0.02). Conclusions: Impairment of the digital hyperemic response at eight months is associated with restenosis after primary intervention in patients with ACS, suggesting the potential of RH-PAT as a noninvasive test for identifying patients with a high risk of restenosis.