Arterial stiffness estimation in healthy subjects: a validation of oscillometric (Arteriograph) and tonometric (SphygmoCor) techniques

Arterial stiffness is an important cardiovascular risk marker, which can be measured noninvasively with different techniques. To validate such techniques in healthy subjects, we compared the recently introduced oscillometric Arteriograph (AG) technique with the tonometric SphygmoCor (SC) method and their associations with carotid ultrasound measures and traditional risk indicators. Sixty-three healthy subjects aged 20-69 (mean 48+/-15) years were included. We measured aortic pulse wave velocity (PWVao) and augmentation index (AIx) by AG and SC, and with SC also the PWVao standardized to 80% of the direct distance between carotid and femoral sites (St-PWVaoSC). The carotid strain, stiffness index and intima-media thickness (cIMT(mean)) were evaluated by ultrasound. PWV(ao)AG (8.00+/-2.16ms(-1)) was higher (P<0.001) than PWVaoSC (6.87+/-1.47ms(-1)), but did not differ from St-PWVaoSC (7.68+/-1.58ms(-1)), and correlated (P<0.001) with both (r =0.54 and 0.59). St-PWVaoSC was significantly (P<0.01) higher than PWV(ao)AG for values below median (7.4 ms(-1)). PWVao by SC and AG differed significantly in females (P<0.001), but not in males (P =0.40). AIx(ao)AG (27.5+/-14.5%) was higher (P<0.001) than AIx(ao)SC (20.5+/-17.4%), but related closely (r =0.97, P<0.001). St-PWVaoSC, PWVao and AIx(ao) by SC, and PWVao and AIx(ao) by AG were all related to serum cholesterol and to cIMT(mean) (P<0.001). Arterial stiffness indices by AG and SC correlate with vascular risk markers in healthy subjects. AIxao results by AG and SC are closely interrelated, but higher values are obtained by AG. In the lower range, PWVao values by AG and SC are similar, but differ for higher values. Our results imply the necessity to apply one and the same technique for repeated studies.