Stiffness index derived from digital volume pulse as a marker of target organ damage in untreated hypertension

OBJECTIVE: An index of large artery stiffness (SIDVP) simply derived from the digital volume pulse (DVP) was developed recently. However, the role of the SIDVP in untreated hypertensive patients was not well elucidated. METHODS: We enrolled 124 untreated hypertensive patients (mean age 55.4+/-13.1 years, 57 men). The DVP was measured in right index finger by a photoplethysmography. The SIDVP was formulated as body height divided by transition time from early systolic peak to the inflection point of reflection wave. Two functional indices of aortic compliance, stiffness index (SI) and distensibility (DI), were also used for measurement of aortic stiffness. RESULTS: The SIDVP was significantly correlated with blood urea nitrogen (BUN), and left ventricular mass index (LVMI). Patients with vascular diseases had higher level of SIDVP (10.12+/-2.97 vs 8.45+/-1.78, p<0.001), SI (13.76+/-7.63 vs 10.87+/-8.88, p=0.116), BUN (28.4+/-24.7 vs 14.5+/-4.6, p<0.001) and lower level of DI (1.34+/-0.88 vs 1.93+/-1.12, p=0.010) than those without vascular diseases. By multivariate analysis, only the SIDVP was significantly associated with vascular diseases (OR 1.39, 95% CI 1.06-1.82, p=0.016). CONCLUSIONS: SIDVP, SI and DI were significantly correlated with target organ damage in untreated hypertension. However, only the SIDVP was independently associated with presence of vascular diseases. SIDVP simply derived from the DVP can be used as a marker for risk stratification in untreated hypertensive patients.