PP.17.30

Abstract

Objective: Recently, it has been revealed that orthostatic hypotension (OH) is a risk factor associated with the onset of cardiovascular disease (CVD). Increased arterial stiffness and autonomic nervous dysfunction is considered to be one of the important causes of OH. However, there are few reports of the association between arterial stiffness, autonomic nervous function and OH. Therefore, we evaluated the interconnectedness of arterial stiffness, autonomic nervous function and OH in patients with atherosclerosis risk factors. Design and method: We studied 652 patients having atherosclerosis risk factors such as hypertension, dyslipidemia and diabetes mellitus. Cardio-ankle vascular index (CAVI) was measured as an index of arterial stiffness. Blood pressure and heart rate measurements were performed during sit-to-stand orthostatic stress test to evaluate the heart rate variability (HRV) and orthostatic change in blood pressure and heart rate. Results: A significant negative correlation was found between orthostatic systolic blood pressure (SBP) change and CAVI (P < 0.001). LogLF (low frequency component) at all phase (rest phase, initial orthostatic phase and delayed orthostatic phase) and logHF (high frequency component) at all phase (except delayed orthostatic phase) had significant negative correlation with age. LogLF at all phase and logHF at all phase (except resting phase) had significant positive correlation with initial orthostatic SBP change. CAVI had a significant negative correlation with logLF at all phase and logHF at all phase (except delayed orthostatic phase). In the multiple regression analysis, initial orthostatic SBP change had a significant correlation with CAVI, logLF and logHF while orthostatic stress test, independent of age and gender (CAVI; P < 0.001, log LF at initial orthostatic phase; P = 0.020, logLF at delayed orthostatic phase; P = 0.026 and logHF at delayed orthostatic phase; P = 0.004). Conclusions: In patients with atherosclerosis risk factor, increased arterial stiffness and decreased HRV independently associated with orthostatic blood pressure decrease regardless of age and gender while their interrelationship exists. Decreased HRV caused by decreased baroreflex sensitivity while orthostatic stress may be one of the important mechanisms that links OH with CVD.