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 Hemodynamic Basis of Portal Hypertension

Anatomy

  • Anatomy of the liver.
  • Anatomy of the portal circulation.
  • Anatomy of the hepatic arterial circulation.
  • Anatomy of the collateral circulation.

Regulation of hepatic blood flow

  • Regulation of the portal circulation.
  • Regulation of the hepatic arterial blood flow (intrinsic, extrinsic).
  • Hepatic artery:portal vein interactions.

Pathophysiology of portal hypertension

  • Increased intrahepatic resistance (pathology, pathophysiologic sequels).
  • Hyperdynamic circulation (definition, mechanisms, pathophysiologic sequels).
  • The role of increased circulating vasodilators (glucagon, prostacyclin, NO).
  • The role of reduced response to endogenous vasoconstrictors.
  • The role of the sympathetic nervous system.
  • The role of plasma volume.

Extrahepatic responses to portal hypertension

  • Cardiac and systemic hemodynamics.
  • Gastrointestinal effects.

References

Ekataksin W, Kaneda K. Liver microvascular architecture: an insight into the pathophysiology of portal hypertension. Semin Liver Dis 1999;19:359-382.

The liver microvascular architecture is described in detail in this paper. The implications of the microvascular structure for hepatic hemodynamics and portal hypertension are also discussed.

Rockey DC . Cellular pathophysiology of portal hypertension and prospects for management with gene therapy. Clin Liver Dis 2001;5:851-865.

The structural, cellular, and humoral factors involved in the regulation of sinusoidal blood flow in normal and injured liver are reviewed in this article. The role of the stellate cells and the modulation of their function by the endothelin and NO systems is discussed. These systems represent potential targets for gene therapy.

Blendis L, Wong F. The hyperdynamic circulation in cirrhosis: an overview. Pharmacol Ther 2001;89:221-231.

This article presents an overview of the hyperdynamic circulation in cirrhosis. Based on the available data, the authors propose a two-phase pathogenesis of the hyperdynamic circulation of cirrhosis. Initially, passive vascular relaxation, and the resulting hyperdynamics, appear to be secondary to blood volume expansion. In the second, much more complex phase, active vasodilatation, associated with hyporesponsiveness to vasoconstrictors, especially in the splanchnic bed, increased portosystemic shunting, and the development of new vessels by angiogenesis likely are part of the explanation.

Thuluvath PJ, Yoo HY. Portal Hypertensive gastropathy. Am J Gastroenterol 2002;97:2973-2978.

An overview of portal hypertensive gastropathy is provided in this article, including its pathogenesis, diagnosis, clinical presentation and treatment.

Moller S, Bendtsen F, Henriksen JH. Splanchnic and systemic hemodynamic derangement in decompensated cirrhosis. Can J Gastroenterol 2001;15:94-106.

Patients with cirrhosis and portal hypertension exhibit characteristic hemodynamic changes with hyperkinetic systemic circulation, abnormal distribution of blood volume and neurohumoral dysregulation. The pathophysiologic aspects of these disorders are discussed in this article.

Posted June 2010