Portal hypertension is heightened pressure on the walls of the vein that transports blood from the stomach and intestines to the liver, also known as the portal vein. For the pressure in the vein to be considered high, it must be at least 12 mm Hg, according to common definitions summarized in, for example, Medical Therapy of Portal Hypertension in 2000. Portal vein pressure is different from the two readings health care professionals normally provide when they measure a person's blood pressure. These two readings measure the pressures on arteries when the heart pumps blood and relaxes.
Intrahepatic Causes
Intrahepatic causes of portal hypertension are causes within the liver itself. Liver fibrosis and cirrhosis are common intrahepatic causes. Liver fibrosis is an accumulation of connective tissue proteins, such as collagen in the liver, whereas liver cirrhosis is poor liver function and scarring of the liver. Chronic liver diseases such as chronic hepatitis C, as well as frequent use of drugs and alcohol, can lead to fibrosis and cirrhosis. A malfunction of the liver typically causes blood to accumulate in the portal vein, resulting in portal hypertension. According to a study published in the January 2010 issue of "Hepatology," however, there are extremely simple ways of reducing the complications of liver fibrosis and scarring. The study indicates that a little more than two cups of coffee a day can put a significant damper on the development of fibrosis and cirrhosis in patients with chronic hepatitis C, and hence reduce portal hypertension. The researchers are not sure whether the beneficial effects of coffee on liver disease stem from the coffee itself or the caffeine it contains.
Prehepatic Causes
Prehepatic causes of portal hypertension are causes within the portal vein. The most common prehepatic causes are clots in or constrictions of the portal vein itself. High levels of high density lipoprotein, or HDL, cholesterol is a leading cause of clots in and constrictions of the body's blood vessels, including the portal vein. Less frequent prehepatic causes of portal hypertension include appendicitis and cancers of the liver, kidneys, pancreas or adrenal glands. Portal vein thrombosis, or clots, can lead to severe liver stiffness, bleeding and death. Surprisingly, an ultra-low dose of aspirin can prevent and reduce the severity of portal vein thrombosis, according to a study published in the October 2007 issue of "World Journal of Gastroenterology."
Post-hepatic Causes
Post-hepatic causes of postal hypertension are causes in the veins leading away from the liver or the regions of the heart receiving blood from the liver. As a Dutch research team points out in a review of post-heptic causes of postal hypertension published in September 2008 issue of "The Netherlands Journal of Medicine," when clots or constrictions prevent the natural flow of blood away from the liver, blood can accumulate in the portal vein leading into the liver, causing portal hypertension. Budd-Chiari syndrome, a condition of this sort, occurs when clots obstruct the large-sized veins that transport blood from the liver to the inferior vena cava, a vein leading into the heart. Because the liver cleans de-oxygenated blood from other organs and sends it back to the heart for re-oxygenation, a malfunction of the heart can also interfere with normal blood flow, thereby causing postal hypertension.
References
- "Portal Hypertension: Diagnostic Imaging and Imaging-Guided Therapy"; Medical Therapy of Portal Hypertension; L. Capocaccia, et al.; 2000
- "World J Gastroenterol"; Modifications Produced by Selective Inhibitors of Cyclooxygenase and Ultra Low Dose Aspirin on Platelet Activity in Portal Hypertension; Francisco X Eizayaga, et al.; October 2007
- "The Netherlands Journal of Medicine"; Vascular Liver Disorders (I): Diagnosis, Treatment and Prognosis of Budd-Chiari Syndrome;J. Hoekstra and H.L.A. Janssen; September 2008
- "Hepatology"; Increased Caffeine Consumption is Associated with Reduced Hepatic Fibrosis; Apurva A Modi et al.; January 2010
