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Mesenteric varices: an entity with specific clinical, angiographic features
Abstract:
Eight Japanese patients with mesenteric varices were diagnosed by angiography. All patients suffered from portal hypertension and had a history of previous abdominal surgery or peritonitis. The mesenteric varices of these patients were thought to be related to adhesion. Of the eight patients, five showed hepatic encephalopathy. None of the patients had a history of massive lower-gastrointestinal bleeding. All mesenteric varices were opacified in the portal phase of superior mesenteric arteriograms. To study the superior mesenteric artery, 50-60 ml of 76% Urografin was injected after infusion of prostaglandin E1 or F2 alpha. Regarding patients treated in the early part of the study, a vasodilator was not used and the contrast dosage was modest. In all eight patients, the mesenteric varices communicated with the systemic venous circulation through the gonadal veins. In seven cases, the mesenteric varices on the right side of the mesenteries drained into the right gonadal veins which flowed into the inferior vena cava (IVC). In the remaining case, the mesenteric varix on the left side drained into the left gonadal vein which flowed into the left renal vein. In three patients with right-sided varices, venous blood sampled from the right gonadal vein and from the distal and proximal IVC showed a high concentration of ammonia in the right gonadal vein and step-ups between distal and proximal IVC.
Insights
Mesenteric varices in Japanese patients, often linked to adhesions after surgery, can cause hepatic encephalopathy. These varices connect to the systemic circulation via gonadal veins, potentially shunting ammonia directly to the brain.
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.