CARDIOVASCULAR AND RENAL EFFECTS OF LOW-DOSE ATRIAL-NATRIURETIC-PEPTIDE IN COMPENSATED CIRRHOSIS

Patients with cirrhosis and ascites have high plasma levels of atrial natriuretic peptide (ANP). Pharmacological doses of this hormone usual ly worsen systemic hemodynamics of cirrhotic patients, We assessed whe ther ANP influences cardiovascular homeostasis and renal function in p atients with compensated cirrhosis at plasma levels comparable to thos e observed in patients with cirrhosis and ascites. Methods: Radionucli de angiocardiography was performed in eight compensated cirrhotic pati ents during placebo (three periods of 15 min each) and ANP infusion (2 , 4, and 6 pmol/kg.min for 15 min each), together with appropriate blo od and urine sampling, to evaluate left ventricular diastolic, systoli c, and stroke volume, heart rate, cardiac output, arterial pressure, p eripheral vascular resistance, creatinine clearance, urinary sodium ex cretion, plasma renin activity, plasma aldosterone, norepinephrine and hematocrit. Results: The infusion increased plasma ANP up to levels ( 52.03 +/- 2.29 pmol/L) comparable with those observed in 35 patients w ith ascites (46.42 +/- 1.57 pmol/ L). This increment was associated wi th significant reductions in left ventricular end diastolic volume, st roke volume, cardiac index (from 3.7 +/- 0.7 to 3.1 +/- 0.5 L/min.m(2) , p < 0.85) and mean arterial pressure (from 96.7 +/- 6.5 to 88.5 +/- 9.5 mmHg, p < 0.05), while heart rate and hematocrit significantly inc reased. Peripheral vascular resistance did not change. These hemodynam ic effects occurred despite significant increases in plasma renin acti vity and norepinephrine. ANP also induced increases in creatinine clea rance, urinary sodium excretion, and fractional sodium excretion. Conc lusions: Low-dose ANP affected cardiovascular homeostasis and renal so dium handling in compensated cirrhosis, suggesting that this hormone m ay be involved in the pathophysiology of systemic hemodynamic and rena l functional abnormalities of cirrhosis.