Morbidity and mortality of portal hypertension.

Portal hypertension occurs in several aetiologically distinct disease states associated with either increased flow or increased resistance in the portal venous system. The morbidity and mortality observed are the result of ascites formation, impaired hepatic metabolism, encephalopathy and, most ominously, variceal haemorrhage. Patients with conditions in which there is relatively little hepatic parenchymal damage (non-cirrhotic portal hypertension) tend to have fewer episodes of encephalopathy and are better able to tolerate bleeding episodes than those patients with underlying cirrhosis. Similarly, the development of ascites varies with respect to the aetiology of the portal hypertension. This chapter discusses the natural history of the various disease states that manifest portal hypertension, thus allowing critical evaluation of the various therapeutic modalities used in its treatment.

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.

The effects of ethanol administration on portal pressure and gastroesophageal collateral blood flow in patients with alcoholic cirrhosis.

The pathogenesis of variceal hemorrhage is not well understood. Portal pressure and gastroesophageal collateral (azygous) blood flow are similar in patients with cirrhosis with or without a history of variceal bleeding. However, acute increases in these parameters in individual patients might predispose them to variceal rupture. Fifteen patients with alcoholic cirrhosis and portal hypertension were evaluated to test the hypothesis that ethanol intake acutely increases portal pressure or gastroesophageal blood flow and is a possible risk factor in variceal hemorrhage. A 10% solution of ethanol in 5% dextrose in water was infused intravenously at a rate sufficient to raise the blood-alcohol level to 100 mg/dl over 30 min. Eight patients received ethanol 5% dextrose in water; seven patients received a placebo (5% dextrose in water alone). Ethanol did not produce a significant change in wedged hepatic-vein pressure, free hepatic-vein pressure, azygous blood flow, mean arterial pressure or heart rate compared with the effects of 5% dextrose in water alone. Acute administration of ethanol does not increase portal pressure or gastroesophageal blood flow. It is unlikely that acute ethanol ingestion is a risk factor for variceal hemorrhage.

Effects of vasopressin on portal pressure during hemorrhage from esophageal varices.

Vasopressin is often used to treat variceal hemorrhage. However, its efficacy is uncertain, and its portal hemodynamic effects in this setting are unknown. Eleven patients with alcoholic liver disease and bleeding varices were given vasopressin (0.2 U/min for the first hour, then 0.4 U/min for 24 hours). Portal pressure was monitored using an indwelling hepatic vein balloon catheter. Seventeen patients with variceal bleeding who remained stable over 26 hours of initial treatment with crystalloid and blood products served as a comparison group. Vasopressin infusion (0.2 U/min) produced a significant decrease in wedged hepatic venous pressure, hepatic venous pressure gradient (wedged minus free hepatic venous pressure), and heart rate. Increases in the rate of infusion did not produce further decreases in the parameters measured, but the changes were sustained over the course of the infusion. Hemodynamics remained stable in the control group. Portal pressure did not increase when vasopressin was abruptly discontinued in the 3 patients in whom postinfusion measurements were made. Vasopressin retains its portal hypotensive effects in the setting of variceal hemorrhage. Tachyphylaxis does not develop over 26 hours, and a "rebound" increase in portal pressure probably does not occur when the infusion is discontinued.

Assessment of the risk of bleeding from esophageal varices by continuous monitoring of portal pressure.

Portal pressure was monitored by means of an indwelling hepatic vein balloon catheter in patients with alcoholic cirrhosis and bleeding varices to determine the safety and feasibility of the technique and its value in predicting recurrence of bleeding. Forty patients were enrolled. Central venous access could not be achieved in 4 patients (10%). Hepatic vein catheterization was accomplished in the remaining 36 patients. Fourteen patients were either later found to have nonalcoholic liver disease or had already received treatment that excluded them from the protocol. The remaining 22 patients, who were treated with blood and fluid replacement, were monitored for up to 72 hours. Portal pressure was greater than 11 mm Hg in all patients (normal, less than 5 mm Hg) and did not change significantly over the 3 days of study. Portal pressure was significantly higher in the 9 patients who continued to bleed or rebled compared with the 13 patients who remained stable. The lowest pressure associated with continued bleeding or rebleeding was 16 mm Hg. Continuous monitoring of portal pressure in patients with bleeding esophageal varices due to alcoholic cirrhosis is safe and feasible and permits rapid stratification of the risk of continued bleeding or early rebleeding.