Estimation of the secretion rate of atrial natriuretic peptide from the coronary sinus in coronary artery disease.

Although atrial natriuretic peptide (ANP) is known to be secreted through the coronary sinus into the systemic circulation, its actual secretion rate has not been thoroughly investigated. The immunoreactive ANP concentrations in plasma samples from the ascending aorta and coronary sinus in 11 patients with the coronary artery disease were measured and the coronary sinus flow rate using the continuous thermodilution method was simultaneously determined at the time of sampling. These variables were also determined during the intravenous infusion of synthetic alpha-human ANP at 0.025 microgram/kg.min in 7 of the 11 patients. In the basal state, the plasma concentration of ANP was 61 +/- 6 (standard error) pg/ml in the aorta and 541 +/- 40 pg/ml in the coronary sinus, and the coronary sinus flow index was 57.3 +/- 12.3 ml/min.m2. Thus, the secretion rate of ANP was determined to be 14.4 +/- 2.8 ng/min.m2. The secretion rate of ANP correlated significantly with the plasma concentration of ANP in the aorta (r = 0.65, p less than 0.05). The ANP infusion, which decreased pulmonary artery wedge pressure from 8.0 +/- 0.6 to 6.3 +/- 0.4 mm Hg (p less than 0.01), elevated the plasma concentrations of ANP in the aorta and coronary sinus by 701% (p less than 0.001) and 33% (p less than 0.05), respectively, and decreased the secretion rate of ANP by 40% (p less than 0.05). These results suggest that the circulating plasma concentration of ANP may reflect the secretion rate of ANP and that an increase in circulating ANP directly or indirectly reduces ANP secretion.