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| Portacaval anastomosis | |
|---|---|
| Other names | Porto-systemic anastomosisPortal caval system |
Aportacaval anastomosis orportocaval anastomosis is a specific type ofcirculatory anastomosis that occurs between the veins of theportal circulation and thevena cava, thus forming one of the principal types ofportasystemic anastomosis orportosystemic anastomosis, as it connects the portal circulation to thesystemic circulation, providing analternative pathway for theblood. When there is a blockage of the portal system, portocaval anastomosis enables the blood to still reach the systemic venous circulation. The inferior end of theesophagus and the superior part of therectum are potential sites of a harmful portocaval anastomosis.[1]
Inportal hypertension, as in the case ofcirrhosis of the liver, the anastomoses become congested and form venous dilatations. Such dilatation can lead toesophageal varices andanorectal varices.Caput medusae can also result.[2]
Aportacaval shunt is analogous in that it diverts circulation; as withshunts andanastomoses generally, the terms are often used to refer to either the naturally occurring forms or the surgically created forms.
Clinical presentations ofportal hypertension include:
| Region | Name of clinical condition | Portal circulation | Systemic circulation |
|---|---|---|---|
| Esophageal | Esophageal varices | Esophageal branch ofleft gastric vein | Esophageal branches ofazygos vein |
| Rectal | Rectal varices | Superior rectal vein | Middle rectal veins andinferior rectal veins |
| Paraumbilical | Caput medusae | Paraumbilical veins | Superficial epigastric vein |
| Retroperitoneal | Splenorenal shunt[3] | Splenic vein | Renal vein,suprarenal vein,paravertebral vein, andgonadal vein |
| (no clinical name)[4] | Right colic vein,middle colic vein,left colic vein | Retroperitoneal veins of Retzius | |
| Intrahepatic | Hepatic pseudolesions[5] | Perihepatic veins of Sappey | Superior epigastric vein |
| Patent ductus venosus | Left branch of portal vein | Inferior vena cava |
A dilated inferior mesenteric vein may or may not be related to portal hypertension.Other areas of anastomosis include thebare area of the liver as it connects to thediaphragm, the posterior portion of thegastrointestinal tract as it touches the posterior abdominal wall, and the inferior part of the esophagus.