ABSTRACT
OBJECTIVES: We evaluated the magnitude and site of action of the nesiritide mediated renal vasodilatory effect in patients with heart failure (HF). BACKGROUND: Nesiritide, a recombinant human B-type natriuretic peptide is approved for the treatment of acute decompensated HF and has been shown to exert favorable hemodynamic, neurohormonal, and symptomatic effects. The renal effect of nesiritide in HF patients has not been well defined. METHODS: In 15 patients with acute decompensated HF, intravascular Doppler and quantitative angiography of the renal artery were used to assess the effect of nesiritide on renal artery diameter and velocity time integral as well as renal blood flow and vascular resistance. Nesiritide was administered intravenously at a standard dose of 2 microg/kg bolus followed by a continuous infusion at a rate of 0.01 microg/kg/min. Assessment of nesiritide effect was made at 15 min. RESULTS: Nesiritide infusion was associated with a significant central hemodynamic effect including a fall in mean pulmonary artery pressure (36 +/- 12 mm Hg to 31 +/- 13 mm Hg, p < 0.001), mean pulmonary capillary wedge pressure (21 +/- 2 mm Hg to 15 +/- 10 mm Hg, p < 0.001), and systemic vascular resistance (1,995 +/- 532 dynes s cm(-5) to 1,563 +/- 504 dynes s cm(-5), r < 0.001), and an increase in cardiac output from 3.9 +/- 1.2 l/min to 4.6 +/- 1.6 l/min (p = 0.001). Nesiritide was also associated with a significant vasodilatory effect on the large conductance renal arteries resulting in an increase in renal artery diameter from 6.2 +/- 0.7 mm to 6.7 +/- 0.8 mm (p < 0.001). At the same time, there was a concomitant fall in mean renal artery pressure (99 +/- 17 mm Hg to 89 +/- 13 mm Hg, p = 0.002) and renal blood flow velocity time integral (27 +/- 15 cm/beat to 23 +/- 15 cm/beat, p = 0.008) and, therefore, no significant change in renal blood flow or renal vascular resistance. CONCLUSIONS: The nesiritide effect on the renal circulation in patients with HF is complex, with a marked vasodilatory action on the large, conductance renal arteries but a concomitant fall in velocity time integral and no effect on renal vascular resistance or renal blood flow. Lack of increase in renal blood flow may be due to a fall in renal blood pressure or an intrarenal vasoconstrictive effect.
