Effects of acute portal hypertension by portal venous stenosis on systemic hemodynamics in dogs.

Effects of acute portal hypertension on systemic hemodynamics after hepatectomy were evaluated by portal venous stenosis (PVS) model in dogs. In protocol 1, portal hypertension of about twice portal venous pressure (PVP) decreased cardiac output (CO) and left atrial pressure (LAP) by 24.5% (p less than 0.01) and 1.0 mm Hg (p less than 0.01), respectively. In protocol 2, stepwise PVS demonstrated that CO change (%) and LAP change (mm Hg) were inversely proportional to PVP change (r = -0.937 and -0.883, respectively). The ratio of CO change to LAP change with stepwise PVS was comparable to that obtained by repeated hemorrhage in protocol 3. The present study shows that low CO with portal hypertension is caused by a reduction of venous return to the heart.