Role of the Renin-Angiotensin System in the Systemic Vasoconstriction of Chronic Congestive Heart Failure

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Abstract

SUMMARY In 15 patients with severe chronic left ventricular failure, plasma renin activity (PRA) ranged widely, from 0.2-39 ng/ml/hr. The level of PRA was unrelated to cardiac output (CO) or pulmonary artery wedge pressure (PWP), but was slightly negatively correlated with mean arterial pressure (MAP) (r = -0.45) and systemic vascular resistance (SVR) (r = -0.40). After infusion of the angiotensin converting enzyme inhibitor teprotide (SQ 20,881) PWP fell from 26.3 ± 1.3 (SEM) to 20.3 ± 1.4 mm Hg (P < 0.001), CO rose from 3.94 ± 0.23 to 4.75 ± 0.31 1/min (P < 0.001), MAP fell from 87.5 ± 3.8 to 77.9 ± 4.1 mm Hg (P < 0.001) and SVR from 1619 ± 148 to 1252 ± 137 dyne-sec-cm-5 (P < 0.001). The fall in MAP and in SVR was significantly correlated with control PRA (r = 0.68 and r = 0.58, respectively). When subjects were divided on the basis of control PRA the hemodynamic response to teprotide was greatest in the high renin group. PRA rose after teprotide (8.7 ± 3.4 to 37.9 + 7.7 ng/ml/hr, P < 0.05) but plasma norepinephrine fell (619.1 ± 103.6 to 449.7 ± 75.7, P < 0.05). The renin-angiotensin system thus appears to have an important role in the elevated SVR in some patients with heart failure. Chronic inhibition of converting enzyme should be explored as a possible therapeutic approach.

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