Transcapillary Exchange in the Hindlimb and Intestine of Dogs with Right Heart Failure

The effects of chronic right ventricular volume overload, congestive heart failure (HF) on transcapillary exchange of lipid-insoluble solutes in the hindlimb and small intestine were studied in anesthetized dogs. Using the single injection indicator diffusion method, extractions (E), capillary clearances (C), and capillary permeability surface area products (PS) of urea, sucrose, and inulin were measured in the hindlimb and small intestine of 16 control and 14 HF dogs. Right HF was caused by surgically produced tricuspid insufficiency. The HF dogs exhibited increased central venous pressures, right ventricular end diastolic pressure, and heart rates as well as gross ascites and pleural effusion. The small intestine of the HF dogs demonstrated increased E, C and PS values for all three solutes, while no changes were seen in the hindlimb. These changes in the capillary bed of the small intestine could be due to an increase in capillary permeability, and/or capillary surface area.