PS-C05-6: EFFECT OF CORONARY RISK FACTORS AND PRESENCE OF CORONARY ARTERY DISEASE ON DIURNAL VARIATION IN VASCULAR ENDOTHELIAL FUNCTION

Abstract

Purpose: Vascular endothelial dysfunction, an early change in atherosclerosis, is an independent risk factor for cardiovascular disease and is known to be reversible; RH-PAT (Reactive Hyperemia Peripheral Arterial Tonometry) can noninvasively measure vascular endothelial function. However, it is difficult to interpret the pathological significance of a single measurement because of many modifying factors such as diet, temperature, and medications. In this study, we aimed to investigate the effects of coronary risk factors and the presence of coronary artery disease on the diurnal variation of vascular endothelial function. Methods: Between May 2013 and May 2015, 498 patients (31% female, 19–94 years old, mean 66.7 ± 12.5 years) who were admitted to our hospital for cardiac catheterization, percutaneous coronary angioplasty, catheter ablation, or lower extremity peripheral angioplasty underwent RH-PAT examination (The Endo PAT 2000 system, Itamar Medical Ltd, Caesarea, Israel). The correlation between coronary risk factors and RH-PAT results was investigated. Correlations between coronary risk factors and RH-PAT results were also examined in patients who underwent coronary angiography. Results: The Reactive Hyperemia Index (RHI) was significantly lower in the group with smoking habit than in the nonsmoking group. Neither the number of coronary artery branches involved, the presence or absence of atrial fibrillation, nor the responsiveness to coronary spasm induction tests correlated significantly with the RHI. On the other hand, there was a significant difference between the morning and afternoon measurements in the group without coronary artery lesions, but no significant difference between the morning and afternoon measurements in the group with coronary artery lesions, regardless of the number of lesioned branches. Conclusions: Patients with a history of smoking, coronary artery lesions, and coronary spasms may have impaired diurnal variation in vascular endothelial function, suggesting that RH-PAT may be useful as an early indicator of coronary artery disease when measured at different time points.