Nitroglycerin for portal hypertension. A controlled comparison of the hemodynamic effects of graded doses

Nitroglycerin is reportedly an effective treatment for portal hypertension. However, the effects of graded doses have not been examined. We administered nitroglycerin intravenously to 10 patients with alcoholic cirrhosis, beginning at 10 micrograms/min and doubling the dose every 10 min thereafter until mean arterial pressure fell 10-15 mmHg. We compared the response to that of 10 patients receiving a control infusion. The median infusion rate of nitroglycerin was 40 micrograms/min (range 10-160 micrograms/min). Nitroglycerin significantly reduced cardiac output as well as pulmonary artery, pulmonary capillary and mean arterial pressure. The overall effects of nitroglycerin on the hepatic venous pressure gradient and azygous (gastroesophageal collateral) blood flow were heterogeneous. However, the hepatic venous pressure gradient significantly increased in nitroglycerin-treated patients with high pulmonary capillary pressures (greater than or equal to 12 mmHg) compared to control patients with similar cardiac filling pressures at both median and maximum rates of infusion. Nitroglycerin is therefore not a uniformly effective treatment for portal hypertension. Cardiac filling pressure may be a determinant of the splanchnic hemodynamic response to nitroglycerin.