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Portal Hypertension

By

Danielle Tholey

, MD, Sidney Kimmel Medical College at Thomas Jefferson University

Last full review/revision Jan 2021| Content last modified Jan 2021
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Portal hypertension is elevated pressure in the portal vein. It is caused most often by cirrhosis (in developed countries), schistosomiasis (in endemic areas), or hepatic vascular abnormalities. Consequences include esophageal varices and portosystemic encephalopathy. Diagnosis is based on clinical criteria, often in conjunction with imaging tests and endoscopy. Treatment involves prevention of gastrointestinal bleeding (GI) bleeding with endoscopy, drugs, or both and sometimes with portacaval shunting or liver transplantation.

The portal vein, formed by the superior mesenteric and splenic veins, drains blood from the abdominal GI tract, spleen, and pancreas into the liver. Within reticuloendothelium-lined blood channels (sinusoids), blood from the terminal portal venules merges with hepatic arterial blood. Blood flows out of the sinusoids via the hepatic veins into the inferior vena cava.

Normal portal pressure is 5 to 10 mm Hg (7 to 14 cm H2O), which exceeds inferior vena caval pressure by 4 to 5 mm Hg (portal venous gradient). Higher values are defined as portal hypertension.

Etiology of Portal Hypertension

Portal hypertension results mainly from increased resistance to blood flow in the portal vein. A common cause of this resistance is disease within the liver Pathophysiology The liver is a metabolically complex organ. Hepatocytes (liver parenchymal cells) perform the liver’s metabolic functions: Formation and excretion of bile as a component of bilirubin metabolism... read more ; uncommon causes include blockage of the splenic or portal vein and impaired hepatic venous outflow (see table Most Common Causes of Portal Hypertension Most Common Causes of Portal Hypertension Portal hypertension is elevated pressure in the portal vein. It is caused most often by cirrhosis (in developed countries), schistosomiasis (in endemic areas), or hepatic vascular abnormalities... read more ). Increased flow volume is a rare cause, although it often contributes to portal hypertension in cirrhosis and in hematologic disorders that cause massive splenomegaly.

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Pathophysiology of Portal Hypertension

In cirrhosis Cirrhosis Cirrhosis is a late stage of hepatic fibrosis that has resulted in widespread distortion of normal hepatic architecture. Cirrhosis is characterized by regenerative nodules surrounded by dense... read more , tissue fibrosis and regeneration increase resistance in the sinusoids and terminal portal venules. However, other potentially reversible factors contribute; they include contractility of sinusoidal lining cells, production of vasoactive substances (eg, endothelins, nitric oxide), various systemic mediators of arteriolar resistance, and possibly swelling of hepatocytes.

Over time, portal hypertension Portal Hypertension Portal hypertension is elevated pressure in the portal vein. It is caused most often by cirrhosis (in developed countries), schistosomiasis (in endemic areas), or hepatic vascular abnormalities... read more creates portosystemic venous collaterals. They may slightly decrease portal vein pressure but can cause complications. Engorged serpentine submucosal vessels (varices) in the distal esophagus and sometimes in the gastric fundus can rupture, causing sudden, catastrophic gastrointestinal bleeding Varices Varices are dilated veins in the distal esophagus or proximal stomach caused by elevated pressure in the portal venous system, typically from cirrhosis. They may bleed massively but cause no... read more Varices . Bleeding rarely occurs unless the portal pressure gradient is > 12 mm Hg. Gastric mucosal vascular congestion (portal hypertensive gastropathy) can cause acute or chronic bleeding independent of varices. Visible abdominal wall collaterals are common; veins radiating from the umbilicus (caput medusae) are much rarer and indicate extensive flow in the umbilical and periumbilical veins. Collaterals around the rectum can cause rectal varices that can bleed.

Portosystemic collaterals shunt blood away from the liver. Thus, less blood reaches the liver when portal flow increases (diminished hepatic reserve). In addition, toxic substances from the intestine are shunted directly to the systemic circulation, contributing to portosystemic encephalopathy Portosystemic Encephalopathy Portosystemic encephalopathy is a neuropsychiatric syndrome that can develop in patients with liver disease. It most often results from high gut protein or acute metabolic stress (eg, gastrointestinal... read more . Venous congestion within visceral organs due to portal hypertension contributes to ascites via altered Starling forces. Splenomegaly and hypersplenism Splenomegaly Splenomegaly is abnormal enlargement of the spleen. (See also Overview of the Spleen.) Splenomegaly is almost always secondary to other disorders. Causes of splenomegaly are myriad, as are the... read more commonly occur as a result of increased splenic vein pressure. Thrombocytopenia Overview of Platelet Disorders Platelets are cell fragments that function in the clotting system. Thrombopoietin helps control the number of circulating platelets by stimulating the bone marrow to produce megakaryocytes,... read more Overview of Platelet Disorders , leukopenia Lymphocytopenia Lymphocytopenia is a total lymphocyte count of 1000/mcL ( 1 × 109/L) in adults or 3000/mcL ( 3 × 109/L) in children 2 years. Sequelae include opportunistic infections and an increased risk of... read more , and, less commonly, hemolytic anemia Overview of Hemolytic Anemia At the end of their normal life span (about 120 days), red blood cells (RBCs) are removed from the circulation. Hemolysis is defined as premature destruction and hence a shortened RBC life span ( read more Overview of Hemolytic Anemia may result.

Portal hypertension is often associated with a hyperdynamic circulation. Mechanisms are complex and seem to involve altered sympathetic tone, production of nitric oxide and other endogenous vasodilators, and enhanced activity of humoral factors (eg, glucagon).

Symptoms and Signs of Portal Hypertension

Diagnosis of Portal Hypertension

  • Usually clinical evaluation

Portal hypertension is assumed to be present when a patient with chronic liver disease has collateral circulation, splenomegaly, ascites Ascites Ascites is free fluid in the peritoneal cavity. The most common cause is portal hypertension. Symptoms usually result from abdominal distention. Diagnosis is based on physical examination and... read more , or portosystemic encephalopathy Portosystemic Encephalopathy Portosystemic encephalopathy is a neuropsychiatric syndrome that can develop in patients with liver disease. It most often results from high gut protein or acute metabolic stress (eg, gastrointestinal... read more . Proof requires measurement of the hepatic venous pressure gradient, which approximates portal pressure, by a transjugular catheter; however, this procedure is invasive and usually not done. Imaging may help when cirrhosis is suspected. Ultrasonography or CT often reveals dilated intra-abdominal collaterals, and Doppler ultrasonography can determine portal vein patency and flow.

Esophagogastric varices and portal hypertensive gastropathy are best diagnosed by endoscopy, which may also identify predictors of esophagogastric variceal bleeding (eg, red markings on a varix).

Prognosis for Portal Hypertension

Mortality during acute variceal hemorrhage may exceed 50%. Prognosis is predicted by the degree of hepatic reserve and the degree of bleeding. For survivors, the bleeding risk within the next 1 to 2 years is 50 to 75%. Ongoing endoscopic or drug therapy lowers the bleeding risk but decreases long-term mortality only marginally. For treatment of acute bleeding, Overview of Gastrointestinal Bleeding Overview of Gastrointestinal Bleeding Gastrointestinal (GI) bleeding can originate anywhere from the mouth to the anus and can be overt or occult. The manifestations depend on the location and rate of bleeding. (See also Varices... read more and Varices: Treatment Treatment Varices are dilated veins in the distal esophagus or proximal stomach caused by elevated pressure in the portal venous system, typically from cirrhosis. They may bleed massively but cause no... read more Treatment .

Treatment of Portal Hypertension

  • Ongoing endoscopic therapy and surveillance

  • Nonselective beta-blockers with or without isosorbide mononitrate

  • Sometimes portal vein shunting

When possible, the underlying disorder is treated.

In patients with esophagogastric varices that have bled, combined endoscopic and drug treatment decreases mortality and reduces risk of rebleeding better than either therapy used alone. A series of endoscopic banding sessions are done to obliterate residual varices, then periodic endoscopic surveillance is done to identify and treat recurrent varices. Long-term drug therapy usually involves nonselective beta-blockers; these drugs lower portal pressure primarily by diminishing portal flow, although the effects vary. Agents include propranolol (40 to 80 mg orally twice a day), nadolol (40 to 160 mg orally once a day), timolol (10 to 20 mg orally twice a day), and carvedilol (6.25 to 12.5 mg orally twice a day), with dosage titrated to decrease heart rate by about 25%. Adding isosorbide mononitrate 10 to 20 mg orally twice a day may further reduce portal pressure (1 Treatment reference Portal hypertension is elevated pressure in the portal vein. It is caused most often by cirrhosis (in developed countries), schistosomiasis (in endemic areas), or hepatic vascular abnormalities... read more ).

In patients with esophagogastric varices that have not yet bled (ie, for primary prophylaxis), outcomes are similar with beta blocker therapy or endoscopic therapy.

Patients who do not adequately respond to either treatment should be considered for transjugular intrahepatic portosystemic shunting (TIPS) or, less frequently, a surgical portacaval shunt. In TIPS, the shunt is created by placing a stent between the portal and hepatic venous circulation within the liver. (See also the American Association for the Study of Liver Diseases [AASLD] practice guideline The Role of Transjugular Intrahepatic Portosystemic Shunt [TIPS] in the Management of Portal Hypertension: Update 2009.) Although TIPS may result in fewer immediate deaths than surgical shunting, particularly during acute bleeding, maintenance of patency may require repeat procedures because the stent may become stenosed or occluded over time. Long-term benefits are unknown. Liver transplantation Liver Transplantation Liver transplantation is the 2nd most common type of solid organ transplantation. (See also Overview of Transplantation.) Indications for liver transplantation include Cirrhosis (70% of transplantations... read more may be indicated for some patients.

For bleeding due to portal hypertensive gastropathy, beta blockers can be used to decrease portal pressure. A shunt should be considered if drugs are ineffective, but results may be less successful than for esophagogastric variceal bleeding.

Because it rarely causes clinical problems, hypersplenism requires no specific treatment, and splenectomy should be avoided.

Treatment reference

Key Points

  • Portal hypertension is caused most often by cirrhosis (in developed countries), schistosomiasis (in endemic areas), or hepatic vascular abnormalities.

  • Complications can include acute variceal bleeding (with a high mortality rate), ascites, splenomegaly, and portosystemic encephalopathy.

  • Diagnose portal hypertension based on clinical findings.

  • To help prevent acute variceal bleeding, initiate periodic surveillance and endoscopic banding sessions.

  • To help prevent rebleeding, treat with nonselective beta-blockers with or without isosorbide mononitrate, transjugular intrahepatic portosystemic shunting (TIPS), or both.

Drugs Mentioned In This Article

Drug Name Select Trade
MONOKET
INDERAL
COREG
CORGARD
TIMOPTIC
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