Distribution of renal blood flow in dogs with congestive heart failure

Studies were performed to determine whether the intrarenal distribution of cortical blood flow is altered in congestive heart failure. Utilizing the radioactive microsphere method, we studied eight dogs that developed congestive heart failure secondary to the construction of an aortocaval fistula. They had marked reduction in total renal blood flow not accompanied by intracortical redistribution of blood flow. All dogs had developed edema and/or ascites, and gained a mean of 3.4 kg; glomerular filtration rate, hematocrit, and urinary sodium excretion fell significantly. Renal vascular resistance increased; mean blood pressure and filtration fraction were unchanged. Furosemide was administered to a second group of nine fistula dogs. The drug produced a marked natriuresis associated with a decrease in outer cortical blood flow (zone 1) and an increase in midcortical zones 2 and 3; no change was observed in zone 4. We conclude: 1) chronic salt retention occurs in high-output heart failure in the absence of redistribution of renal cortical blood flow, and 2) the effect of furosemide on intrarenal hemodynamics of dogs with heart failure is similar to that seen in normal animals.