Background: Natriuretic peptides are useful markers for risk stratification of patients with heart disease. However, conflicting results have been reported about circulating atrial natriuretic peptide (ANP) concentration in heart transplant recipients.
Methods: To ascertain the effects of diabetes and acute insulin administration on plasma ANP concentrations in a model of heart denervation, we studied 12 diabetic (D-OHT) and 6 nondiabetic heart-transplanted (OHT) patients using the euglycemic-hyperinsulinemic clamp and oral glucose tolerance tests. Five patients with type 2 diabetes without heart transplantation (D) and 9 healthy subjects (NOR) matched for anthropometric features served as the controls.
Results: Means baseline plasma ANP concentration was higher in D-OHT (82 +/- 15 pg/mL) than in OHT or NOR (27 +/- 4 or 30 +/- 5; P < .01), but was not different than D (69 +/- 12; P = .82). During the clamp plasma ANP showed similar increases in all groups (49 +/- 4, 39 +/- 3, 59 +/- 4, and 49 +/- 3% in D-OHT, OHT, D, and NOR; P < .02 vs basal, P = NS among groups). Plasma osmolarity and catecholamines were also not different among groups and did not increase during the clamp. Fasting plasma ANP concentrations correlated with plasma glucose concentrations measured 120 minutes after oral glucose tolerance testing.
Conclusions: Among heart transplantation recipients fasting plasma ANP concentrations were not different at 5 to 6 years after the surgical procedure than in nondiabetic controls. Increased ANP concentrations were observed among recipients with diabetes and among nontransplanted diabetic patients. Although the insulin-induced increment in ANP concentrations was not different among groups, circulating ANP was strongly associated with glucose tolerance status.