Reduced venous compliance in normotensive men with positive family histories of hypertension.

Abstract

To test the hypothesis of reduced venous compliance and increased cardiovascular responses to volume expansion and alpha-agonist stimulation. Non-hypertensive healthy young men with positive (PFH) and negative family histories of hypertension were investigated regarding peripheral haemodynamics and changes in central venous pressure (CVP) and arterial blood pressure in response to graded doses of phenylephrine and acute i.v. fluid volume loading (1000 saline solution in 10 min). The control group was divided into one group matched for body mass index to PFH subjects (NFHO) and one lean control group (NFHN). Supine blood pressure was higher in PFH and NFHO subjects compared with NFHN subjects, whilst CVP was similar in the three groups at baseline. No significant differences in calf or forearm haemodynamics or blood volume were observed between the three groups. Cardiovascular responses to bolus doses of phenylephrine did not differ between the three groups. Saline infusion significantly increased CVP and systolic blood pressure, and effective vascular compliance (change in blood volume: CVP ratio) was reduced in PFH subjects. PFH subjects have decreased effective vascular compliance and altered arterial blood pressure responses to acute increases in vascular fluid volume. This may result from multiple factors such as increased venous vascular tone, structural reduction of venous distensibility and/or an altered neurohormonal response to increased CVP.