Effects of propranolol on gastric mucosal perfusion and serum gastrin level in cirrhotic patients with portal hypertensive gastropathy

An Update: Portal Hypertensive Gastropathy and Colopathy

Complications of portal hypertension include portal hypertensive gastropathy and colopathy. These disorders may cause chronic or acute gastrointestinal bleeding. The diagnosis is made endoscopically; therefore, there is great variability in their assessment. Portal hypertensive gastropathy can range from a mosaic-like pattern resembling snakeskin mucosa to frankly bleeding petechial lesions. Portal hypertensive colopathy has been less well-described and is variably characterized (erythema, vascular lesions, petechiae). Treatment is challenging and results are inconsistent. Currently, available evidence does not support the use of beta-blockers for primary prevention. Further investigation of the pathogenesis, natural history, and treatment of these disorders is needed.

Portal hypertensive gastropathy: A systematic review of the pathophysiology, clinical presentation, natural history and therapy

AIM

To describe the pathophysiology, clinical presentation, natural history, and therapy of portal hypertensive gastropathy (PHG) based on a systematic literature review.

METHODS

Computerized search of the literature was performed via PubMed using the following medical subject headings or keywords: "portal" and "gastropathy"; or "portal" and "hypertensive"; or "congestive" and "gastropathy"; or "congestive" and "gastroenteropathy". The following criteria were applied for study inclusion: Publication in peer-reviewed journals, and publication since 1980. Articles were independently evaluated by each author and selected for inclusion by consensus after discussion based on the following criteria: Well-designed, prospective trials; recent studies; large study populations; and study emphasis on PHG.

RESULTS

PHG is diagnosed by characteristic endoscopic findings of small polygonal areas of variable erythema surrounded by a pale, reticular border in a mosaic pattern in the gastric fundus/body in a patient with cirrhotic or non-cirrhotic portal hypertension. Histologic findings include capillary and venule dilatation, congestion, and tortuosity, without vascular fibrin thrombi or inflammatory cells in gastric submucosa. PHG is differentiated from gastric antral vascular ectasia by a different endoscopic appearance. The etiology of PHG is inadequately understood. Portal hypertension is necessary but insufficient to develop PHG because many patients have portal hypertension without PHG. PHG increases in frequency with more severe portal hypertension, advanced liver disease, longer liver disease duration, presence of esophageal varices, and endoscopic variceal obliteration. PHG pathogenesis is related to a hyperdynamic circulation, induced by portal hypertension, characterized by increased intrahepatic resistance to flow, increased splanchnic flow, increased total gastric flow, and most likely decreased gastric mucosal flow. Gastric mucosa in PHG shows increased susceptibility to gastrotoxic chemicals and poor wound healing. Nitrous oxide, free radicals, tumor necrosis factor-alpha, and glucagon may contribute to PHG development. Acute and chronic gastrointestinal bleeding are the only clinical complications. Bleeding is typically mild-to-moderate. Endoscopic therapy is rarely useful because the bleeding is typically diffuse. Acute bleeding is primarily treated with octreotide, often with concomitant proton pump inhibitor therapy, or secondarily treated with vasopressin or terlipressin. Nonselective β-adrenergic receptor antagonists, particularly propranolol, are used to prevent bleeding after an acute episode or for chronic bleeding. Iron deficiency anemia from chronic bleeding may require iron replacement therapy. Transjugular-intrahepatic-portosystemic-shunt and liver transplantation are highly successful ultimate therapies because they reduce the underlying portal hypertension.

CONCLUSION

PHG is important to recognize in patients with cirrhotic or non-cirrhotic portal hypertension because it can cause acute or chronic GI bleeding that often requires pharmacologic therapy.

N/A

N/A

Role of acute elevation of portal venous pressure by exogenous glucagon on gastric mucosal injury in rats with portal hypertension

Time-course studies revealed the increased susceptibility of the gastric mucosa to noxious injury in portal hypertension correlates with the level of elevated portal venous pressure and hyperglucagonemia. Whether acute elevation of portal venous pressure by exogenous glucagon aggravates such injury is not known. We tested the hypothesis that glucagon in a dose sufficient to acutely elevate portal venous pressure aggravates noxious injury of the gastric mucosa in rats with portal hypertension. Infusion of a portal hypotensive dose of somatostatin should reverse these changes. In anesthetized rats with portal vein ligation, glucagon, somatostatin or the combination was administered intravenously in a randomized, coded fashion. Acidified ethanol-induced gastric mucosal injury was determined. Portal venous pressure and gastric mucosal perfusion and oxygenation (reflectance spectrophotometry) were monitored to confirm the effects of the respective intravenous treatments. Exogenous glucagon exacerbated acidified ethanol-induced gastric mucosal injury. The exacerbation was attenuated by somatostatin. These changes paralleled the portal hypertensive and hypotensive effects of glucagon and somatostatin, respectively. Our data suggest that a unique mechanism is triggered with the onset of portal hypertension. In an antagonistic manner, glucagon and somatostatin modulate this novel mechanism that controls portal venous pressure and susceptibility of the gastric mucosa to noxious injury.

Gastric motility in patients with presinusoidal portal hypertension

OBJECTIVE

The aim of this study was to evaluate the consequences of portal hypertension (PH) for the motor functions of the human stomach.

METHODS

The PH model used was the hepatosplenic form of mansonic schistosomiasis, as this is a condition characterized by PH but with considerably preserved hepatocellular function. The study included 15 patients with PH and 25 healthy volunteers who served as controls. The adaptive relaxation of the stomach was studied in 12 patients with PH and in 10 controls by a manometric method during rapid insufflation (25-30 s) of 700 ml of air into the gastric fundus. The gastric emptying of a liquid solution (15 patients with PH and 20 controls) and of a solid-liquid meal (nine patients with PH and 12 controls) was determined by gamma scintigraphy. The thickness of the gastric antrum wall was measured by ultrasonography in 12 patients with PH and in 10 controls.

RESULTS

Patients with PH showed the following: 1) reduction of the adaptive relaxation of the stomach (p < 0.0001); 2) acceleration of gastric emptying of the test solution (T 1/2, p = 0.0316), which became particularly expressive 25, 30, 40, and 50 min after ingestion (p = 0.0181, 0.0215, 0.0181, and 0.0215, respectively); 3) no alteration in gastric emptying of the solid-liquid meal as judged by T 1/2 values (p = 0.9170) or lag-phase values (p = 0.7544); and 4) a conspicuous increase in gastric wall thickness as determined by antrum wall measurements (p = 0.0008).

CONCLUSIONS

The reduced gastric adaptive relaxation demonstrated in patients with PH and normal hepatocellular function leads us to consider this condition as a cause of diastolic dysfunction of the stomach. In this disease, the motor alteration may be explained as a consequence of the reduction of gastric wall compliance, probably resulting from edema and vascular ectasia, which were indirectly detected by the increase thickness of the gastric antrum wall. The discrete acceleration of liquid gastric may be also related to the reduced gastric wall compliance.

Comparison of the efficacy of octreotide, vasopressin, and omeprazole in the control of acute bleeding in patients with portal hypertensive gastropathy: a controlled study

BACKGROUND

Portal hypertensive gastropathy is an important complication of liver cirrhosis and it contributes to acute gastric bleeding. Effective management of this condition remains a clinical challenge. We assessed and compared the efficacy of octreotide, vasopressin, and omeprazole in the treatment of acute bleeding in patients with portal hypertensive gastropathy.

METHODS

Sixty-eight patients with portal hypertensive gastropathy were randomized into Octreotide, Vasopressin, and Omeprazole groups. Bleeding was monitored by observing the contents of the nasogastric tube. Blood transfusion requirements and side-effects of drugs were recorded. Repeat endoscopies were scheduled 2 weeks after treatment.

RESULTS

Complete bleeding control after 48 h of drug infusion was achieved in all patients receiving octreotide (100%), 14/22 patients receiving vasopressin (64%), and 13/22 patients receiving Omeprazole (59%). Octreotide required much less time and significantly fewer blood transfusions to control bleeding. Patients receiving vasopressin experienced more side-effects than those receiving octreotide and omeprazole. In the 17 patients whose bleeding was not controlled within 48 h by either vasopressin or omeprazole, complete bleeding control was achieved by combined use of these two agents. Follow-up endoscopy showed dramatic improvement in gastric mucosal erosions, superficial ulceration and erythema.

CONCLUSIONS

Octreotide appeared to be more effective in controlling acute bleeding in patients with hypertensive gastropathy, with significantly rapid action, smaller transfusion requirements, and minor side-effects. Simultaneous administration of vasopressin and omeprazole appeared to have additive effects.

Portal-hypertensive gastropathy

In the present article we describe updated information concerning the clinical feature of portal-hypertensive gastropathy (PHG), which is characterized by mucosal and submucosal vascular dilatation without inflammation. Although this lesion represents non-variceal bleeding, there is a wide variation of its prevalence. Portal pressure and some humoral factors may play important roles in its pathogenesis. Gastric acid secretory activity is reduced, whereas the gastric mucosal barrier is impaired. With regard to gastric mucosal haemodynamics, whether 'overflow' (i.e. active congestion) or 'stasis' (i.e. passive congestion) cause gastric mucosal hyperaemia is not known. A severe lesion is a potential source of bleeding, while mild lesions are of little clinical significance and endoscopic variceal obliteration aggravates PHG in some patients. In the treatment of PHG, pharmacological (e.g. propranolol), surgical (e.g. portosystemic shunt) and radiological (e.g. transjugular intrahepatic portosystemic shunt) procedures may be useful in preventing bleeding from PHG.

Underlying mechanisms of portal hypertensive gastropathy

Gastric mucosal lesions are frequently observed in patients with liver cirrhosis and portal hypertension. Similar lesions can be observed in experimental portal hypertension. This review summarizes our current knowledge of the pathophysiology of portal hypertensive gastropathy, with a particular focus on the microcirculatory disturbances that characterize this condition. The stomach of cirrhotic patients exhibits an increased susceptibility to injury induced by several irritants. Similarly, the stomach of portal hypertensive animals is less resistant to injury. One of the most important factors contributing to the increased susceptibility to damage is an impaired hyperemic response when the epithelium is exposed to irritants. This appears to be related to a reduction in mucosal prostaglandin production and to altered microcirculatory responsiveness to nitric oxide. Nitric oxide overproduction in portal hypertension may have direct effects on gastric blood flow regulation. Elevated production of tumor necrosis factor-alpha by gastric mucosa in portal hypertensive rats has also been shown to contribute to mucosal injury. A better understanding of the pathogenesis of portal hypertensive gastropathy may lead to development of specific therapeutic interventions for this condition.

Vasopressin plus oxygen vs vasopressin alone in cirrhotic patients with portal-hypertensive gastropathy: effects on gastric mucosal haemodynamics and oxygenation

The effects of vasopressin plus oxygen and vasopressin alone on gastric mucosal perfusion and oxygenation were studied using reflectance spectrophotometry and laser Doppler velocimetry in 23 cirrhotic patients with portal-hypertensive gastropathy. The measurements were performed under basal conditions and after double-blinded administration of placebo (n = 7), vasopressin (0.3 U/min; n = 8) or vasopressin (0.3 U/min) plus nasal oxygen (4 L/min; n = 8). No significant effects on gastric mucosal haemodynamics and oxygenation were observed after placebo. In contrast, vasopressin and vasopressin plus oxygen induced a similar reduction in haemoglobin content (-26 +/- 2 and -21 +/- 4%, respectively P < 0.01), and laser Doppler signal (-23 +/- 2 and -22 +/- 2%, respectively, P < 0.01). Although each treatment induced a significant reduction in oxygen saturation (-21 +/- 2 and -7 +/- 1%, respectively P < 0.01), the effect was less pronounced in patients receiving the combination than in those receiving vasopressin alone (P < 0.01). These data suggest that vasopressin and vasopressin plus oxygen reduce gastric mucosal hyperaemia and that the oxygen supplement partially protects against gastric mucosal hypoxia during vasopressin infusion in cirrhotic patients with portal-hypertensive gastropathy.