Various noninvasive in vivo assessments have recently been applied to the estimation of atherosclerosis in subjects with diabetes. The measurement of pulse-wave velocity (PWV) has been popular with the advance of apparatus, especially in Japan (1–3). However, it remains unknown whether PWV may be valid and reproducible, especially in diabetic study populations (4). In a recent issue of Diabetes Care, Hope et al. (5) addressed the important question of whether it is valid to apply PWV in diabetic subjects. They found that the generalized transfer function, as derived in an index population, did not describe the relationship between peripheral and central arterial waveforms (4,5).
In the present study, we examined the relationship between PWV and another technique to evaluate the early atherosclerotic lesion, i.e., intima-media thickness (IMT) of the carotid artery in subjects with type 2 diabetes and those without it. IMT of the common carotid artery was measured with high-resolution B-mode ultrasonography (SSA-770A; Toshiba, Tokyo, Japan) with an electrical linear transducer (midfrequnecy 7.5 MHz), as previously reported (6,7). The localized thickness >2.0 mm was excluded as plaque lesion (6). Brachial-ankle PWV (baPWV) was measured with an automated device (ABI-form; Nippon Colin, Komaki, Japan) that can monitor bilateral brachial and ankle-pressure wave forms using the volume plethysmographic method (1–3). The study population included a total of 245 consecutive Japanese subjects with type 2 diabetes (128 men and 117 women, mean age 65.6 ± 9.2 years [means ± SD]) and a total of 91 subjects without diabetes (35 men and 56 women, mean age 62.3 ± 9.9 years). Although there was a significant positive correlation between baPWV and IMT in subjects with diabetes, the coefficient was very small (r2 = 0.033, P < 0.005). In contrast, there was a significant correlation with high coefficient between baPWV and IMT in subjects without diabetes (r2 = 0.286, P < 0.0001). Furthermore, baPWV was not significantly related to the presence of plaque in either group.
This preliminary result suggests that PWV is not a feasible index for the early atherosclerotic lesion. It is not, at least in diabetic subjects, considered to be an equivalent to IMT or plaque, which are established indexes for early and advanced atherosclerotic lesion, respectively. Our result was in contrast to another report (1) that indicated a significant positive correlation between PWV and IMT in both diabetic (r = 0.482) and control (r = 0.424) subjects. It remains to be elucidated whether PWV can be used as a reliable index to evaluate antiatherogenic action of some drug in diabetic subjects (3).
