Objectives: To evaluate changes in atrial natriuretic factor in relation to modifications in hemodynamic variables, and to evaluate hormones determining salt and water metabolism after heart surgery in children with congenital heart disease.
Design: Prospective study.
Setting: Medical-surgical pediatric intensive care unit (ICU) in a tertiary referral center.
Patients: Sixty-five infants and children admitted to the pediatric ICU with congenital heart disease who underwent cardiac surgery with extracorporeal circulation. The control group consisted of 48 children undergoing noncardiac surgical interventions, without a history of cardiac disease and with normal hemodynamic variables.
Measurements and main results: Patients with congenital heart disease were distributed into two groups, according to hemodynamic variables. Group 1 consisted of patients with normal pulmonary blood flow (pulmonary/systemic blood flow ratio of < 2, pulmonary arterial systolic pressure of < 35 mm Hg, pulmonary arterial systolic pressure/aortic systolic pressure ratio of < 0.35). Group 2 consisted of patients with relatively increased pulmonary blood flow (pulmonary/systemic blood flow ratio of > 2.5, pulmonary arterial systolic pressure of > 65 mm Hg, pulmonary arterial systolic pressure/aortic systolic pressure ratio of > 0.75). Blood samples were obtained 24 hrs before, and 24 and 48 hrs after surgery. Hormone determinations included plasma concentrations of atrial natriuretic factor, vasopressin, plasma renin activity, corticotropin, cortisol, and aldosterone. Hemodynamic measurements were recorded simultaneously with blood sampling. Twenty-four hours before surgery, plasma concentrations of atrial natriuretic factor were higher in congenital heart disease patients than in the control group (67.36 +/- 93.44 vs. 15.11 +/- 8.29 pmol/L) (p < .001). Plasma concentrations of atrial natriuretic factor were 57.12 +/- 82.20 and 74.63 +/- 101.03 pmol/L in groups 1 and 2, respectively. Before surgery, in group 2 patients, there was a significant correlation between mean right atrial pressure and atrial natriuretic factor (r2 = .64; p < .001), vasopressin (r2 = .55; p < .001), cortisol (r2 = .43; p < .01), corticotropin (r2 = .53; p < .01), and aldosterone (r2 = .57, p < .001). None of these correlations were observed in group 1. However, 24 hrs after surgery, we found a significant correlation between diastolic blood pressure and atrial natriuretic factor in group 1. Plasma concentrations of atrial natriuretic factor did not change significantly after surgery. After surgery, the correlation between mean right atrial pressure and the various hormone concentrations persisted at 24 hrs (p < .05), but not at 48 hrs. Twenty-four hours after surgery, patients with a central venous pressure of > 7 mm Hg showed higher concentrations of atrial natriuretic factor than those patients with central venous pressures of < 7 mm Hg (p < .05). However, there was a large overlap of atrial natriuretic factor values between the two groups.
Conclusions: Patients with congenital heart disease have increased plasma concentrations of atrial natriuretic factor. During the early postoperative period, in patients with a more severe degree of congenital heart disease, the increase in central venous pressure correlated with higher plasma concentrations of atrial natriuretic factor. High pulmonary blood flow was associated with an increase in plasma renin activity and serum aldosterone, and an increased secretion of atrial natriuretic factor.