Mesenteric varices: an entity with specific clinical, angiographic features.

Area of Science:

• Vascular Surgery
• Gastroenterology
• Radiology

Background:

• Mesenteric varices are rare vascular anomalies.
• Portal hypertension is a common predisposing factor.
• Previous abdominal surgery and peritonitis are implicated in their development.

Purpose of the Study:

• To investigate the characteristics and venous drainage of mesenteric varices in Japanese patients.
• To explore the relationship between mesenteric varices, portal hypertension, and hepatic encephalopathy.

Main Methods:

• Diagnosis of mesenteric varices using angiography, specifically superior mesenteric arteriograms.
• Administration of prostaglandin E1 or F2 alpha prior to contrast injection.
• Venous blood sampling from gonadal veins and inferior vena cava (IVC) to measure ammonia levels.

Main Results:

• Eight Japanese patients with mesenteric varices were identified, all with portal hypertension and a history of abdominal surgery or peritonitis.
• Five patients presented with hepatic encephalopathy; none had massive lower-gastrointestinal bleeding.
• All mesenteric varices communicated with the systemic venous circulation via gonadal veins, draining into the IVC or left renal vein.
• Elevated ammonia levels were detected in the right gonadal vein and between distal and proximal IVC in patients with right-sided varices.

Conclusions:

• Mesenteric varices are associated with portal hypertension and may develop secondary to adhesions from prior abdominal insults.
• The drainage of mesenteric varices into the gonadal veins provides a direct route for ammonia to reach the systemic circulation.
• This venous communication may contribute to the development of hepatic encephalopathy in affected patients.