William G. Rector

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.

Atrial volume in cirrhosis: Relationship to blood volume and plasma concentration of atrial natriuretic factor

Increased blood volume, atrial size, and plasma concentration of atrial natriuretic factor are described in cirrhosis. Their interrelationships were examined in 17 men with alcoholic liver disease, 7 with and 10 without ascites. Atrial size was determined by two-dimensional echocardiography. Patients with cirrhosis had significantly increased left atrial volume and plasma concentration of atrial natriuretic factor when compared with normal male subjects. Right atrial volume was normal in patients with cirrhosis, as was left ventricular function. Patients with ascites had significantly increased blood volume and plasma atrial natriuretic factor concentration compared with patients without ascites. Left and right atrial volume did not differ between the groups. Blood volume correlated significantly with left atrial volume, which correlated significantly with plasma concentration of atrial natriuretic factor. Cirrhosis is associated with related increases in vascular volume, left atrial size, and plasma atrial natriuretic factor concentration. Increased blood volume probably contributes to the increase in left atrial volume, which is in turn one reason for the elevation of plasma atrial natriuretic factor concentration.

Pathogenesis of Sodium Retention Complicating Cirrhosis: Is There Room for Diminished “Effective” Arterial Blood Volume?

We measured total blood volume (125I-albumin), cardiac dimensions and function (echocardiography with Doppler), systemic hemodynamics (blood pressure and pulse), and plasma renin activity and norepinephrine levels in cirrhotic patients with and without ascites to assess the likelihood that either diminished central or arterial filling is the stimulus to sodium retention. Patients with ascites (n = 9) had significantly increased total blood volume, cardiac output, pulse rate, plasma renin activity, and plasma norepinephrine concentration, as well as decreased systemic vascular resistance and arterial blood pressure compared with patients without ascites (n = 8). Left atrial size was similar in the two groups but significantly larger than in normal control subjects. Right and left atrial pressures were also similar in retrospectively studied patients with and without ascites. Sodium retention in cirrhosis is probably not triggered by diminished central filling. Increased blood volume is compatible with either a primary hepatorenal stimulus to sodium retention or a signal arising from a region of underfilling within an otherwise expanded circulation. If the latter model is correct, a hyperdynamic systemic circulation and increased plasma neurohormone concentrations may indicate effective arterial underfilling in patients with ascites.

Caffeine clearance in cirrhosis: The value of simplified determinations of liver metabolic capacity

Less complex methods of measuring hepatic metabolic capacity are needed. A simplified caffeine clearance test was evaluated in 23 patients with stable alcoholic liver disease. First, saliva caffeine concentrations were measured over a 24-h caffeine-free interval. Clearance was calculated from the rate of elimination of caffeine and an assumed volume of distribution and compared with the results of a formal clearance test using sequential plasma and saliva samples following a 300 mg oral dose. The simplified method was then assessed in 11 hospitalized patients with cirrhosis. Saliva caffeine concentrations remained measurable over the interval of study in 82% of patients. Caffeine clearance as determined by the simplified method did not differ from plasma caffeine clearance after an oral dose. Application of this method was achieved in 11 of 12 patients hospitalized for complications of severe liver disease, and revealed markedly diminished clearance. Thus, caffeine clearance can be accurately estimated in patients with severe liver disease using two or more samples of either saliva or plasma. This simplified determination of caffeine elimination rate provides a more practical assessment of hepatic metabolic capacity than a formal clearance test.

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.

Arterial underfilling does not cause sodium retention in cirrhosis

PURPOSEnTo test the peripheral arterial vasodilation hypothesis of sodium retention in cirrhosis. This states that sodium retention is triggered by arterial underfilling and predicts that development of sodium retention will be associated with significant and related declines in indices of arterial filling that reverse when sodium retention resolves.nnnDESIGNnLongitudinal evaluation of a cohort of patients with alcoholic liver disease.nnnPATIENTS AND METHODSnEighteen men, 8 of whom were studied twice, 3 three times, 2 four times, and 5 five times (40 between-study comparisons). Between 23 studies, the patients were ascites-free (Group NN). Ascites spontaneously disappeared between seven studies (Group YN), appeared between six studies (Group NY), and remained present between four studies (Group YY). Between-study changes in blood volume, arterial blood pressure, cardiac output, systemic vascular resistance, left atrial volume, left ventricular diastolic diameter, aortic root diameter, aortic blood velocity, plasma norepinephrine and atrial natriuretic factor concentrations, plasma renin activity, and urinary sodium excretion were evaluated by paired t-tests. These changes were also compared among groups by analysis of variance. In addition, correlations among the changes were sought.nnnRESULTSnSystolic, diastolic, and mean arterial pressures, left ventricular diastolic diameter, aortic root diameter, stroke volume, cardiac output, plasma norepinephrine concentration, and systemic vascular resistance were unchanged between studies. Left atrial volume increased between studies in Group NY. Pulse pressure fell more in Group NY than in Groups NN and YN, principally as a result of a decline in systolic blood pressure. Plasma norepinephrine concentration, plasma renin activity, and blood volume rose more in Group NY than in Groups NN, YN, and YY. Changes in both systolic and pulse pressures were directly correlated with the change in sodium excretion but unrelated to the change in plasma norepinephrine concentration. Changes in plasma norepinephrine concentration and plasma renin activity were unrelated to changes in blood pressure, systemic vascular resistance, and urinary sodium excretion.nnnCONCLUSIONSnNone of the indices of arterial filling tested except pulse pressure were related to sodium retention. Reduced pulse pressure is inconsistent with arterial underfilling, as peripheral vasodilation instead increases pulse pressure by increasing diastolic run-off. These data do not support the hypothesis that arterial underfilling is the stimulus for sodium retention in alcoholic cirrhosis.

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.

Morbidity and Mortality of Portal Hypertension

SummaryPortal 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.

Vasopressin and vasopressin plus nitroglycerin for portal hypertension: Effects on systemic and splanchnic hemodynamics and coronary blood flow

We measured the coronary, systemic, and splanchnic effects of vasopressin and vasopressin plus nitroglycerin in 8 stable patients with alcoholic cirrhosis. Vasopressin (0.1-0.8 U/min) increased pressure in the hepatic vein, pulmonary artery and pulmonary capillaries. Wedged hepatic (portal) vein pressure was unchanged; the hepatic venous pressure gradient (wedged-free hepatic vein pressure) fell. Insignificant declines occurred in cardiac output, gastroesophageal collateral (azygous) blood flow, hepatic blood flow and coronary sinus (cardiac) blood flow. The addition of nitroglycerin (40-70 micrograms/min) reduced pressure in the hepatic vein, pulmonary artery and pulmonary capillaries, while increasing the hepatic venous pressure gradient. Wedged hepatic vein pressure did not change. Gastroesophageal collateral (azygous) flow increased markedly; cardiac output rose to a lesser degree. Coronary sinus and hepatic blood flow did not change. Nitroglycerin ameliorated the increases in systemic and pulmonary artery pressure produced by vasopressin but also tended to reverse the decline in the hepatic venous pressure gradient and markedly increased gastroesophageal flow. Neither drug significantly affected coronary blood flow.

Plasma renin activity in alcoholic liver disease

PURPOSE AND PATIENTS AND METHODSnThe relationship of plasma renin activity (PRA) to indices of circulatory filling and other possible determinants of renin secretion was studied in 31 men with alcoholic liver disease. Characteristics of patients with normal and increased PRA values were examined. Significant differences guided subsequent simple and multiple regression analysis.nnnRESULTSnSupine PRA was increased (greater than 2.4 ng/mL/h on a 200 mEq/d intake of sodium, ranging as high as 33 ng/mL/h) in 14 of 57 studies. Nonascitic patients with elevated PRA values were significantly younger than those with normal PRA values. Among patients without ascites, the plasma atrial natriuretic factor concentration correlated inversely with PRA. Ascitic patients with elevated PRA values had a significantly reduced serum sodium concentration, urinary sodium excretion, creatinine clearance, and arterial pressure. Systemic vascular resistance, plasma norepinephrine and caffeine concentrations, and left atrial volume were similar in patients with and without increased PRA values. Univariate followed by multiple regression analysis identified age and plasma atrial natriuretic factor concentration as significant independent correlates of PRA in patients without ascites (R2 = 0.54). Serum sodium concentration and urinary sodium excretion were significant correlates of PRA in patients with ascites (R2 = 0.80).nnnCONCLUSIONnThe associates of PRA in alcoholic liver disease are diverse and potentially complex. Age and plasma atrial natriuretic factor concentration are important in patients without ascites. In patients with ascites, tubular delivery of sodium to the macula densa, as modified by the filtered load and proximal reabsorption, appeared to be a principal association of PRA. Indices of circulatory filling did not emerge as clearly independent associations of PRA. Increased PRA values in patients with ascites may be an effect of sodium retention rather than part of its cause.