ATRIAL NATRIURETIC PEPTIDE IN PATIENTS WITH CARDIAC IMPAIRMENT DUE TO OPEN HEART SURGERY

Abstract

Plasma levels of atrial natriuretic peptide (ANP) were determined in eight patients with cardiac impairment after open heart surgery. Catheters were placed in the coronary sinus and exteriorized through the subclavian vein in seven patients during the surgery. After the operation, a Swan-Ganz catheter was inserted, and one catheter each was placed in the peripheral artery and urinary bladder. Right atrial pressure (RAP) and pulmonary artery wedge pressure (PAWP) were measured at 10 : 00 p.m. on the day of the operation and at 10 : 00 a.m. on the following day. When measurements of atrial pressure were performed, blood was obtained for determinations of plasma level of ANP, plasma renin activity (PRA) and plasma aldosterone concentration (PAC). Urine was collected from 0 : 00 a.m. after the operation for 10 hours, and parameters of renal function were measured, including creatinine clearance (Ccr), free water clearance (FWC) and fractional excretion of sodium (FENa).Plasma concentrations of ANP correlated significantly (p<0.05) with PAWP, but not with RAP, PRA, PAC, Ccr, FWC or FENa. There was a significant (r=0.82, p<0.05) correlation between ANP levels in coronary sinus and peripheral artery the former was four times higher (p<0.05) than the latter.These findings suggest an important role of left atrial pressure in the release of ANP in patients with cardiac impairment due to open heart surgery. The high concentration of ANP in coronary sinus in the present study supports the consideration that ANP synthesized in the atria enters into circulation through the coronary sinus.