Association between home arterial stiffness index and target organ damage in hypertension: Comparison with pulse wave velocity and augmentation index

Objectives: To clarify the implications of the home arterial stiffness index (HASI), we compared HASI with other arterial stiffness measures and investigated the association between HASI and hypertensive target organ damage (TOD). Methods: We assessed brachial-ankle pulse wave velocity (baPWV) and the carotid augmentation index (cAIx) as measures of arterial stiffness and wave reflection, and the left ventricular mass index (LVMI), carotid intima-media thickness (IMT) using ultrasonography, and the urinary albumin/creatinine ratio (UACR) as measures of TOD in 356 never-treated hypertensive subjects. Home blood pressure (BP) was taken in triplicate in the morning and evening, respectively, for 14 consecutive days with a memory-equipped device. HASI was defined as 1 minus the respective regression slope of diastolic on systolic BP. Results: HASI was significantly correlated with age (r= 0.32, P< 0.001), home pulse pressure (r= 0.36, P< 0.001), morning-evening difference in home systolic BP (r= -0.29, P< 0.001), baPWV (r= 0.18, P< 0.001), cAIx (r= 0.16, P= 0.002), carotid IMT (r= 0.26, P< 0.001), and UACR (r= 0.24, P< 0.001), but not with LVMI (r= 0.05, P= 0.38). After adjustment for age and sex, the significant correlation between HASI and baPWV/cAIx was lost. In multivariate regression analyses, HASI and baPWV were significantly associated with carotid IMT (standardized β= 0.21, P< 0.001; β= 0.14, P= 0.014) and UACR (β= 0.13, P= 0.018; β= 0.21, P< 0.001), independently of age, sex, and home mean arterial pressure. On the other hand, cAIx was independently associated only with LVMI (β= 0.24, P< 0.001). Conclusion: These findings indicate that HASI adds nothing to the existing measures of arterial stiffness, but might be a BP component that can aid in the detection of carotid atherosclerosis and renal damage, similar to PWV.