A controlled clinical trial of cimetidine in the recurrence of variceal hemorrhage: implications about the pathogenesis of hemorrhage

Editorial: Clostridium difficile infection: Yet another predictor of poor outcome in cirrhosis

The development of Clostridium difficile infection in cirrhosis is predictive of death, independent of severity of liver disease. The main risk factors are the use of antibiotics and proton-pump inhibitors (PPIs). This is further evidence that supports the wise and cautious use of antibiotics in cirrhosis and suggests avoiding the use of PPIs in these patients except for indications of proven benefit.

Gastroesophageal reflux in cirrhotic patients with esophageal varices without endoscopic treatment

BACKGROUND

Portal hypertension in patients with liver cirrhosis causes manifestations such as esophageal varices, ascites and edema. Some studies have been conducted about the role of esophageal varices in the development of esophageal motor disorders and abnormal gastroesophageal reflux in these patients. Ascites could be a factor promoting gastroesophageal reflux and it has been questioned whether reflux would favor the rupture of varices. However there are a few studies using ambulatory esophageal pH recording in the evaluation of these patients.

AIMS

Evaluate gastroesophageal reflux by pH recording in cirrhotic patients with esophageal varices and possible predictors.

METHODS

Fifty one patients (28 men, 23 women, mean age of 54 years) with liver cirrhosis, diagnosed by clinical, laboratorial, image and histological findings were prospectively evaluated. All patients had esophageal varices confirmed by endoscopy and were submitted to a questionnaire about typical gastroesophageal reflux disease symptoms (heartburn and or acid regurgitation). pH recording was performed with the probe placed 5 cm above the superior lower esophageal sphincter limit, as determined by manometry. Abnormal reflux (% total time with pH < 4 >4.5%) was related to the size of varices, congestive gastropathy, ascites, severity of cirrhosis and typical gastroesophageal reflux disease symptoms.

RESULTS

The caliber of the varices was considered to be small in 30 patients (59%), medium in 17 (33%) and large in 4 (8%), 21 (41%) congestive gastropathy. Ascites was observed in 17 (33%), 32 patients (63%) were classified as Child-Pugh A, 17 (33%) Child-Pugh B and 2 (4%) Child-Pugh C. Twenty seven patients (53%) presented with typical gastroesophageal reflux disease symptoms. Abnormal reflux at pH recording was found in 19 patients (37%). One of them presented with erosive esophagitis at endoscopy. There was no relation between ascites, variceal size, congestive gastropathy and Child-Pugh score and abnormal reflux. There was a correlation between typical gastroesophageal reflux disease symptoms and abnormal reflux.

CONCLUSION

Abnormal gastroesophageal reflux was found in 37% of the patients with hepatic cirrhosis and esophageal varices. Only typical gastroesophageal reflux disease symptoms predicted these findings.

Chaos and predicting varix hemorrhage

Despite a wide array of mechanisms implicated in esophagogastric varix hemorrhage, predicting the onset of bleeding or even identifying the dominant factor in its causation has proved elusive. In this article we re-examine variceal pathophysiology and hypothesize that bleeding is rooted in turbulent portal system flow, a phenomenon embodied in the 'new' science of chaos and the principles of non-linear, rhythmic fluid dynamics. Analogous to forecasting the weather, predicting turbulent flow hinges on defining the initial physical conditions, and, like the field theory of quantum physics, depends on probabilities and instabilities rather than direct proportional analysis. Based on the complex regional and systemic hemodynamic forces and local physical properties underlying formation and perpetuation of esophagogastric varices, we propose, as with climatologic events, that a relatively minor or remote physiologic adjustment may set into motion a sequence of destabilizing splanchnic blood flow kinetics that ultimately causes a varix to erupt. In other words, the onset of varix bleeding derives from a sudden, erratic switch from disorganized but stable to disruptive turbulent variceal blood flow, and as a 'chaotic' phenomenon, is likely to remain for the foreseeable future highly unpredictable.

Prevalence of endoscopic findings in 510 consecutive individuals with cirrhosis evaluated prospectively

Upper gastrointestinal hemorrhage is one of the more important complications of cirrhosis and a major cause of death in such patients. The main sites of bleeding are esophageal varices, gastritis, and peptic ulcers. In order to determine the prevalence of either potential bleeding lesions or of other endoscopic findings in hemodynamically stable individuals with various etiologies of cirrhosis, 510 consecutive cirrhotic patients, evaluated for possible orthotopic liver transplantation (OLTx) underwent an upper gastrointestinal endoscopy for combined diagnostic and therapeutic purposes. The patients were divided into two main groups: 319 patients with parenchymal liver disease and 191 patients with cholestatic liver disease. Gastritis was found significantly more often in patients with parenchymal liver disease than in those with cholestatic liver disease (49.8% vs 30.9%; P less than 0.001). In contrast, the prevalence of esophagitis, esophageal and gastric varices, gastric ulcer, duodenal ulcer, and duodenitis was similar in both groups. Normal endoscopic findings were present in 5.0% of the parenchymal group and 11.5% of the cholestatic group (P less than 0.02). Ascites and encephalopathy were found significantly more often in subjects with parenchymal liver disease as compared to those with cholestatic liver disease. Portal hypertension and its degree, as assessed by the presence and size of esophageal varices, was similar in both groups, and in both groups there was a statistically significant qualitative trend of increasing prevalence of esophageal varices with increasing severity of disease as estimated using Pugh-Child's criteria.

Nonoperative emergency treatment of variceal hemorrhage

The nonoperative management of acute variceal hemorrhage can control acute hemorrhage and allow stabilization of the patient prior to definitive therapy to prevent further bleeding episodes. Balloon tamponade, endoscopic sclerotherapy, and pharmacotherapy can stop acute variceal bleeding. Endoscopic sclerotherapy has the highest reported success rate, decreases the incidence of early rebleeding, and is the recommended first method to control bleeding.

Pathophysiology of portal hypertension and variceal bleeding

Portal hypertension results from an interaction of abnormal intrahepatic resistance and increases in portal blood flow. Intrahepatic resistance is probably multifactorial in nature and may include compression of hepatic veins by regenerating nodules, collagen deposition in sinusoids and venules, hepatocyte enlargement, and constriction of sinusoids by contractile myofibroblasts. The increase in splanchnic blood flow observed is incompletely understood, but it may involve circulating vasodilators and alteration in volume and sodium balance. The end result of these interactions is the development of increased portal pressure and portosystemic collaterals, the most important of which are esophageal varices. The rupture of esophageal varices is a devastating complication of portal hypertension. Increased portal pressure is necessary for the development and rupture of varices but apparently not sufficient, because many patients with elevated portal pressures never bleed. Presumably, local factors must be involved. Variceal wall tension is probably the best single descriptor of risk from variceal hemorrhage. The wall-tension formula unites the contributions of portal pressure, varix size, and wall thickness to variceal rupture. Lowering portal pressure, reducing varix size, and supporting varices in scar tissue may all lower the risk of hemorrhage.

Review: the pharmacological control of variceal bleeding

The haemodynamic effects and clinical uses of drugs used in the management of patients with oesophageal variceal bleeding are reviewed. Vasoconstrictor agents (vasopressin, teripressin) alone or in combination with nitrates continue to be used for acute bleeding episodes, while somatostatin is an alternative. Alpha- and beta-adrenergic blocking drugs and vasodilators which lead to a sustained decrease in portal pressure can be used for the prevention of bleeding episodes, but despite numerous studies the pharmacological treatment of variceal bleeding remains controversial.

Prophylaxis of first variceal hemorrhage in patients with liver cirrhosis

Prophylaxis of bleeding from esophageal varices is a very tempting concept at first glance, especially under the assumption of a high mortality associated with first variceal hemorrhage. Up to now four different measures have been tried for prophylaxis: portacaval shunt operation, devascularization procedures, sclerotherapy, and drugs. With the exception of portacaval shunts, ongoing controlled trials show a weak trend toward reduction of variceal bleeding and prolongation of survival in selected patients with compensated cirrhosis and large varices. However, prophylaxis of first variceal bleeding must still be regarded as experimental and should be restricted to controlled clinical studies.

The effect of cimetidine on platelet function: a study involving gastric fluid measurements

Gastric fluid samples were aspirated 30 and 60 minutes after the ingestion of two 200 mg tablets of cimetidine. The concentration of cimetidine in these samples was measured and their effect on platelet aggregation assessed in vitro. Gastric fluid samples significantly inhibited adrenaline- and ADP-induced platelet aggregation in vitro. In a further series of experiments, cimetidine solutions, at concentrations found in gastric fluid, inhibited platelet aggregation and thromboxane A2 (TXA2) release, in vitro. Ranitidine, another H2-receptor antagonist, was a more potent inhibitor of platelet aggregation than cimetidine. Since ranitidine is also the more potent H2-receptor antagonist which, unlike cimetidine, does not include an imidazole group (which is known to inhibit TXA2 synthesis) in its structure, we conclude that H2 blockade mediates the observed inhibition of aggregation. This platelet anti-aggregatory effect may be relevant to haemostatic mechanisms involved in bleeding peptic ulcers or gastric erosions exposed to high local concentrations of H2-receptor antagonists.

Effects of repeated injection sclerotherapy on acid gastroesophageal reflux

Acid gastroesophageal reflux was determined by long-term pH monitoring in 19 consecutive variceal bleeders after 5 to 20 (mean, 10.3 +/- 1 SEM) sclerotherapy sessions with the flexible endoscope using polidocanol 1% as sclerosant. Fifteen cirrhotics with untreated varices served as controls. Percentage time of esophageal pH less than 4 (3.3 +/- 0.7 SEM vs. 5.2 +/- 2.2 in the controls) and mean duration of reflux episodes (2.9 +/- 0.4 vs. 3.0 +/- 0.7 min) showed no significant differences between both groups. The findings indicate that repeated injection sclerotherapy with the flexible endoscope does not lead to an enhancement of acid gastroesophageal reflux.

Portal venous-esophageal luminal pressure gradient in cirrhosis

The portal venous-esophageal luminal pressure gradient may be more important than the absolute portal venous pressure in explaining hemorrhages caused by esophageal varices. A continuous recording of portal venous pressure and the esophageal luminal pressure enabled the authors to study the gradient between these pressures in 12 cirrhotic patients with varices of different size and under different circumstances, in particular inspiration, expiration, coughing and a Valsalva maneuver. A significant increase of portal venous pressure occurred during inspiration (+15%), coughing (+77%) and Valsalva maneuver (+157%). The value of portal venous-esophageal luminal pressure gradient increased during inspiration (+38%), coughing (+90%) and Valsalva maneuver (+69%) while it decreased during expiration (-14%).

Effect of cimetidine on portal pressure and systemic hemodynamics in patients with and without liver cirrhosis

Portal pressure and systemic hemodynamics were evaluated for 30 minutes after intravenous injection of 400 mg of cimetidine in patients with and without liver cirrhosis when they were operated upon for varying surgical diseases. A transient fall of arterial pressure was seen in both groups of patients, but the change was statistically significant only in those with cirrhosis. Cimetidine did not substantially alter pulse rate, CVP, and portal pressure in both groups. The present results seem to indicate that rapid administration of cimetidine does not induce a fall of portal venous pressure in both cirrhotic and non-cirrhotic patients.

Recent advances in diagnosis and treatment of gastrointestinal hemorrhage in infants and children

Gastrointestinal bleeding is a common and occasionally life-threatening problem in infants and children. A careful history and physical examination as well as the application of new endoscopic and radiographic techniques will reveal the source of hemorrhage in most patients. The utility of recently introduced pharmacologic agents and endoscopic techniques in the treatment of peptic disease and variceal hemorrhage in children remains to be determined. A cooperative effort among pediatricians, radiologists, and surgeons should minimize the morbidity and mortality from gastrointestinal tract bleeding in this population.