Measurement of arterial distensibility and compliance to assess prognosis

Background and aim Total arterial compliance (TAC) reflects arterial function in the entire systemic circulation while distensibility coefficient (DC) is an estimate of local arterial compliance obtained from large elastic arteries. There are few studies relating TAC or DC to outcome. We sought whether DC or TAC predicted outcome in a primary prevention cohort with a spectrum of cardiovascular risk.
Methods Clinical data including blood pressure (BP) and diabetes mellitus (DM) were obtained and Framingham 10-year risk was calculated in 719 primary prevention patients (373 men; age 55 ± 11 years). TAC was calculated from applanation tonometry using the pulse-pressure method, 2D-echocardiography and Doppler, and DC was derived from 2D measurements of the common carotid artery and pulse pressure (PP). Cox regression analysis was performed to determine correlates of outcome.
Results There were 42 deaths (5.8%) and 114 cardiovascular admissions (15.8%) over 57 months. The independent correlates of mortality were Framingham 10-year risk (HR = 1.69; p < 0.0001) and DC (HR = 0.54; p = 0.02) (model chi-square 24.52; p < 0.0001) but not TAC. The independent predictors of the composite outcome of either death or admission for cardiovascular causes were Framingham 10-year risk (HR = 1.28; p = 0.001) and TAC (HR = 0.75; p = 0.006) (model chi-square 21.43; p < 0.0001) but not DC.
Conclusions Measurement of arterial function is independently correlated with outcome in patients with varying degrees of cardiovascular risk, and different aspects identify fatal and non-fatal events. In addition, measurement of TAC and DC adds incremental benefit to Framingham risk scores alone in patients with intermediate cardiovascular risk.