Comparison of two measuring instruments, B-pro and SphygmoCor system as reference, to evaluate central systolic blood pressure and radial augmentation index

A comparison is made of central aortic systolic pressure (CASP) and the radial augmentation index (rAIx) estimated with the B-Pro device and SphygmoCor (as reference) in 104 healthy Caucasians without drug treatment, together with an analysis of the relationship between CASP and rAIx, and arterial stiffness. Peripheral and central blood pressure, and the rAIx were measured with B-pro and SphygmoCor, with determination of the central augmentation index (CAIx), pulse wave velocity (PWV), carotid intima-media thickness (IMT) and the ankle-brachial index (ABI). rAIx as determined with B-Pro was greater than measured with SphygmoCor (5.85; 95% CI: 1.75-9.96), in the same way as CASP, estimated from the transfer function (1.47; 95% CI: 0.47-2.47mmHg) and with the second peak of the radial wave (4.46; 95% CI: 2.80-6.12mmHg). The Pearson correlation coefficient for CASP with B-Pro and SphygmoCor was r=0.937 (P<0.01), with an intraclass correlation of 0.972 (95% CI: 0.959-0.981). In the case of rAIx, the correlation coefficient was r=0.436 (P<0.01), with an intraclass correlation of 0.599 (95% CI: 0.409-0.728). The correlation of CASP (B-pro) with PWV was r=0.558 (P<0.01), with CAIx r=0.253 (P<0.01) and with carotid IMT r=0.442 (P<0.01). The correlation of rAIx (B-Pro) with age was r=0.369 (r<0.01), and with CAIx r=0.463 (P<0.001). Central arterial pressure estimated with B-Pro in healthy Caucasians without drug treatment offers adequate validity vs. the reference standard (SphygmoCor). However, in the estimation of rAIx, some differences with respect to the reference standard have been detected, probably related to measurement of the second peak of the radial wave. Hypertension Research (2012) 35, 617-623; doi:10.1038/hr.2012.3; published online 2 February 2012