Acute effects of dibutyryl cyclic AMP on renal circulation in congestive heart failure.

Acute effects of dibutyryl cyclic AMP (DBcAMP) on hemodynamics, renal circulation and plasma catecholamine levels were examined in 8 patients with congestive heart failure, NYHA functional class II or III. Before and during intravenous infusion of dibutyryl cyclic AMP at 0.1 mg/kg/min for 30 min, hemodynamic variables, renal blood flow (RBF) and plasma catecholamine levels were investigated. 1) DBcAMP increased the cardiac index from 2.69 +/- 0.65 to 3.60 +/- 0.84 liter/min/m2 (+ 33.8%, p less than 0.001) and heart rate from 70.9 +/- 14.3 to 84.1 +/- 15.7 bpm (+ 18.6%, p less than 0.001) and decreased mean aortic pressure from 91.8 +/- 11.3 to 82.5 +/- 9.8 mmHg (-10.1%, p less than 0.001), and systemic vascular resistance from 1840 +/- 570 to 1260 +/- 370 dynes-sec-cm-5 (-31.6%, p less than 0.001). 2) RBF increased from 335 +/- 81 to 517 +/- 188 ml/min (+ 54.3%, p less than 0.05) and renal vascular resistance decreased from 2.33 +/- 0.61 to 1.52 +/- 0.68 x 10(4) dynes-sec-cm-5 (-34.5%, p less than 0.001). 3) Plasma norepinephrine levels increased significantly. The results indicate that DBcAMP is useful for the treatment of congestive heart failure because it improves cardiac hemodynamics by afterload reduction and has a strong vasodilating effect on renal vascular beds.