Comparison of the Assessment of Orthostatic Hypotension Using Peripheral and Central Blood Pressure Measurements

BACKGROUND: Orthostatic hypotension (OH) is associated with falls and cardiovascular events. There is growing evidence that central blood pressure (CBP) is better than peripheral blood pressure (PBP) in predicting adverse outcomes. The objectives of this study were to assess 1) the prevalence of OH identified using PBP and CBP and the levels of agreement, 2) the respective associations between OH and falls and cardiovascular comorbidities, by PBP and CBP, and 3) the association of OH with arterial wall stiffness markers (augmentation pressure (AP) and augmentation index (AI)). METHODS: An observational case-control study of subjects aged 50 years and above was conducted at the University of Alberta Hospital inpatient wards and outpatient clinics. This study used a non-invasive technology called SphygmoCor to assess changes in CBP between lying, 1, 3 and 6 min of standing. AP and AI, which are markers of arterial wall stiffness, were also measured in this study. Dementia, significant psychological problems, and isolation precautions were exclusion criteria. Both PBP and CBP were measured with arm cuffs in lying and standing positions. OH was diagnosed using consensus criteria. RESULTS: Of the 71 participants recruited, mean age was 72.3 ±10.3 years, 52% were males, 32% had a history of falls and 72% had hypertension. OH occurred within 1, 3 or 6 min of standing (transient OH) in 31% by PBP and 27% by CBP (kappa = 0.56). OH persisted for all 6 min (persistent OH) in 16% by both PBP and CBP (kappa = 0.68). A significant relationship was observed between transient OH by CBP and baseline hypertension (P = 0.05) and dyslipidemia (P = 0.02). There was a significant difference in the mean AP between subjects with and without central persistent OH (P = 0.02), but not between subjects with and without peripheral persistent OH. The mean AI was not significantly different between subjects with or without central or peripheral persistent OH and between subjects with and without peripheral or central transient OH. CONCLUSION: Prevalence of OH was similar between PBP and CBP. However, there was only moderate agreement with OH identified by PBP and CBP indicating some inconsistencies across the sample in identifying OH.