Effect of intraportal nitroglycerin on portosystemic hemodynamics in patients with cirrhosis: comparison with i.v. route

We observed 18 patients with portal hypertension and cirrhosis to compare the effects of intraportal nitroglycerin on portosystemic hemodynamics with the i.v. route. Patients received 1 microgram/kg/min of nitroglycerin intravenously (n = 9) or the same dose of nitroglycerin directly into the portal vein (n = 9). Both routes of nitroglycerin significantly reduced mean arterial pressure and this effect was higher with the i.v. route (-28.0% versus -19.3%, p less than 0.02). The portal pressure, as evaluated by the portal venous pressure gradient or hepatic venous pressure gradient, was also reduced significantly in both groups. The fall in portal pressure was higher in the intraportal group, but the difference was not significant (intravenous versus intraportal, -23.9 versus -25.1% in portal venous pressure gradient, -25.2 versus -33.4% in hepatic venous pressure gradient). The hepatic blood flow was maintained despite the significant reduction in portal pressure by both routes. These results indicate that intraportal nitroglycerin decreases portal pressure with a smaller effect on systemic hemodynamics than the i.v. route. We conclude that the oral administration of nitroglycerin, which is a pathway equivalent to the intraportal route, may be more useful than the i.v. (i.e., sublingual) route in the treatment of portal hypertension.