Selective renal vasodilation and active renal artery perfusion improve renal function in dogs with acute heart failure

Renal failure is common in heart failure due to renovascular constriction a nd hypotension. We tested whether selective pharmacological renal artery va sodilation and active renal artery perfusion (ARP) could improve renal func tion without adverse effects on systemic blood pressure in a canine model o f acute heart failure (AHF). AHF was induced by coronary microembolization in 16 adult mongrel dogs. In five dogs, selective intrarenal (IR) papaverin e (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 ar terial pressure followed by administration of IR papaverine (2 mg/min). In five dogs, ARP plus intravenous furosemide was tested. Urine output (UO) an d 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 (U O: 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, ARID 3.52 +/-1.1 ml/min/g) . A combination of these methods in AHF further increased urine output to t wice the normal baseline (10.5 +/-7.5 ml/15 min). Addition of furosemide sy nergistically increased UO above that achieved with ARP alone (5.5 +/-2.6 v ersus 40.3 +/- 24.7 ml/15 min, p=0.03). In conclusion, ARP and selective re nal vasodilation may effectively promote salt and water excretion in the se tting of heart failure, particularly when systemic blood pressure is low.