Abstract

Renal failure is common in heart failure due to renovascular constriction and hypotension. We tested whether selective pharmacological renal artery vasodilation and active renal artery perfusion (ARP) could improve renal function without adverse effects on systemic blood pressure in a canine model of acute heart failure (AHF). AHF was induced by coronary microembolization in 16 adult mongrel dogs. In five dogs, selective intrarenal (IR) papaverine (1, 2, and 4 mg/min) was administered into the left renal artery. In six dogs, ARP was performed in the left renal artery to normalize mean renal arterial pressure followed by administration of IR papaverine (2 mg/min). In five dogs, ARP plus intravenous furosemide was tested. Urine output (UO) and cortical renal blood flow decreased during AHF and were restored by 2 mg/min IR papaverine (UO: baseline 4.2 ± 0.6, AHF 1.6 ± 1.3, IR papaverine 5.8 ± 1.1 ml/15 min; cortical blood flow: baseline 4.3 ± 0.2, AHF 2.4 ± 0.6, IR papaverine 4.2 ± 1.2 ml/min/g) with no significant change in aortic pressure. ARP also increased urine output and cortical renal blood flow (UO: baseline 5.0 ± 1.1, AHF 0.5 ± 0.4, ARP 3.8 ± 3.1 ml/15 min; cortical blood flow: baseline 4.0 ± 0.5, AHF 2.0 ± 0.8, ARP 3.52 ± 1.1 ml/min/g). A combination of these methods in AHF further increased urine output to twice the normal baseline (10.5 ± 7.5 ml/15 min). Addition of furosemide synergistically increased UO above that achieved with ARP alone (5.5 ± 2.6 versus 40.3 ± 24.7 ml/15 min,p = 0.03). In conclusion, ARP and selective renal vasodilation may effectively promote salt and water excretion in the setting of heart failure, particularly when systemic blood pressure is low.