Atherosclerotic cardiovascular diseases such as ischemic heart disease, peripheral artery disease, and stroke are among the major public health problems worldwide due to their impact on outcomes and quality of life. Current guidelines recommend lifestyle modification, exercise therapy, and drug therapy for the prevention and treatment of atherosclerosis [1, 2]. However, atherosclerosis remains asymptomatic until cardiovascular disease event occurs. Therefore, early detection of atherosclerosis is important to identify indiviuals with a high risk for atherosclerotic cardiovascular disease who may benefit from interventions for preventing the subsequent risk. Noninvasive measurements of vascular function have been performed in clinical settings to evaluate the degree of vascular damage and risk of cardiovascular events [3]. Pulse wave velocity is the speed of the blood pressure wave that propagates along the arterial tree and is calculated as the distance between two measuring sites divided by the pulse wave propagation time. Brachial-ankle pulse wave velocity (baPWV) is a marker of arterial stiffness to evaluate vascular function. Several investigators have demonstrated that high baPWV is an independent predictor of cardiovascular events [3].

Arteries are composed of endothelial cells, vascular smooth muscle cells, and extracellular matrix components such as collagen fibers and elastin [4]. Central arteries and peripheral arteries have different in distributions of arterial wall components. Elastin predominates in central arteries. Central arteries have a high elastic capacity to store and release energy caused by the cardiac contraction cycle. Collagen fibers and vascular smooth muscle cells predominate in peripheral arteries. Peripheral arteries have stiff properties and a lower elastic capacity. Since baPWV is assessed using brachial-ankle recording, baPWV reflects a composite measure of central and peripheral arterial stiffness (Fig. 1). In addition, the proximal portion of the aorta is not included from the measure of baPWV (Fig. 1). Several investigators pointed out that baPWV is strongly dependent on the muscular arteries of lower extremities [4, 5]. Therefore, the measuring principles of baPWV suggest that baPWV measurement provides different cardiovascular information than the central arterial stiffness measurement. Carotid-femoral pulse wave velocity (cfPWV) is the standard measure of central arterial stiffness (Fig. 1) [6]. However, cfPWV cannot be used for assessment of arterial stiffness in peripheral arteries. There are a few approaches for evaluating proximal aortic stiffness. Magnetic resonance imaging (MRI) can provide a measurement of proximal aortic stiffness [7]. However, it is difficult to implement MRI for evaluating proximal aortic stiffness in clinical practice due to the high cost and limited number of studies.

Fig. 1
figure 1

The segments of arterial stiffness evaluated by cfPWV, baPWV, and hbPWV

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In this issue of Hypertension Research, Sugawara and colleagues have introduced a method for measurement of proximal aortic stiffness (Fig. 1), named heart to brachium PWV (hbPWV) [8]. hbPWV can be easily measured by recording heart sound or electrocardiograph and arterial pulse waves from an upper arm blood pressure cuff. The authors have shown age-related changes in hbPWV by using cross-sectional data (n = 7868) and longitudinal data (n = 3710, mean follow-up period: 9.1 ± 2.0 years). hbPWV had stronger associations than baPWV with age and Framingham risk score in both cross-sectional data and longitudinal data. hbPWV increased steadily and consistently with age, while baPWV increased with age at an accelerated rate. In their study, hbPWV had a better predictive value of cardiovascular risk (defined as Framingham risk score of more than 10%) than did baPWV. The authors have clearly shown the usefulness of hbPWV for evaluating cardiovascular risk by using baPWV as a comparative measure.

Measurement of hbPWV only requires limited training since the technique does not differ from that for baPWV measurement. It is expected that hbPWV will be a useful marker for evaluating the proximal aortic stiffness and risk of future cardiovascular events. Further studies are needed to confirm the usefulness of hbPWV for predicting future cardiovascular events. hbPWV may provide information concerning vascular stiffness that is different from the information provided by baPWV. However, whether simultaneous measurements of hbPWV and baPWV provide additional information on cardiovascular risk stratification is still unknown. We should advocate more scientific discourse on this new device and method towards improved medical practice in cardiovascular health.