SALT SENSITIVITY OF HYPERTENSION AND RESPONSES TO ANGIOTENSIN-CONVERTING ENZYME-INHIBITION WITH BENAZEPRIL

Salt intake, and the sensitivity of blood pressure (BP) to excessive s alt intake is thought to contribute to the pathogenesis of essential h ypertension in some patients. This study was designed to ascertain whe ther salt sensitivity of BP is a determinant of BP and renal vascular responsiveness to angiotensin converting enzyme (ACE) inhibition. In 2 4 patients with essential hypertension, ranging in age from 30 to 68 y ears, renin status,renal hemodynamics, and sensitivity of BP to steady state changes in salt intake were assessed. Twenty-four hour ambulato ry BP monitoring (ABPM) was employed to measure baseline BP and BP res ponse to 4 weeks' treatment with benazepril at 20 or 40 mg/day. Benaze pril induced a highly-significant reduction in BP (P <.001) and increa se in renal plasma flow (530 +/- 17 to 580 +/- 19 mL/min/1.73 m(2): P < .001). Systolic BP fell from 143 +/- 2 to 129 +/- 2 mm Hg (P <.001), and diastolic BP fell from 91 +/- 1.6 to 80 +/- 2 mm Hg (P <.001). Th e magnitude of the BP and renal vascular response to ACE inhibition wa s not influenced by the sensitivity of BP to salt intake. In a multiva riate analysis neither body mass index nor age influenced the BP respo nse to ACE inhibition or the relationships between salt intake and a B P response to ACE inhibition. We conclude that the factors that influe nce sensitivity of BP to salt intake do not influence the systemic or renal hemodynamic response to ACE inhibition.