Assessment of arterial stiffness index as a clinical parameter for atherosclerotic coronary artery disease

Background: The aim of the present study was to assess the feasibility and usefulness of the arterial stiffness index (ASI) measured non-invasively by computerized oscillometry and by comparing it with the pulse wave velocity (PWV). Methods and Results: The study group comprised 60 consutive patients who underwent coronary angiography and whose aorto-femoral PWV were obtained with a Judkins catheter. The ASI was obtained using Cardio Vision® MS-2000 (IMDP, Las Vegas, NV, USA): (i) baseline (ASI-B); (ii) hyperemia induced by compression of the arm with cuff pressure for 5 min (ASI-H); and (iii) sublingual nitroglycerin (ASI-N). In total, 34 patients had significant coronary artery disease (CAD). The PWV and all ASI were higher in patients with CAD than in those without CAD (ASI-B, 85.9±57.8 vs 48.2±24.5, p=0.001; ASI-H, 98.1±49.8 vs 48.1±21.3, p<0.01; ASI-N, 66.7±55.7 vs 33.2±27.9, p=0.002). However, only ASI-B and ASI-H were positively correlated to the PWV (ASI-B, r=0.27, p=0.03; ASI-H, r=0.49, p=0.001; ASI-N, r=0.19, p=0.16). The ASI was increased after hyperemia in patients with CAD (ASI-H, 85.9±57.8 to 98.1±49.8, p=0.01), but not in patients without CAD (ASI-H, 48.2±24.5 to 48.1±21.3, p>0.01). After adjusting their age, only ASI-H was correlated to the presence of CAD (r=0.33, p<0.01). Conclusions: It is feasible and useful to use the ASI for detection of atherosclerotic coronary disease. The findings of ASI-H suggests that in addition to stiffening of the arterial wall itself, the impairment of flow mediated vasodilation, because of endothelial dysfunction, further increases the arterial stiffness.