Sinistral (Left-sided) Portal Hypertension

Fig. 1: Axial CT image in a 44-year-old woman shows multiple dilated venous collaterals (varices) along the stomach (arrows).
Fig. 2: Axial CT image of the same patient shows a large pancreatic pseudocyst (stars) with absence of the splenic vein, indicating splenic vein thrombosis from chronic pancreatitis.

Sinistral (Left-sided) Portal Hypertension

• Localized form of extrahepatic portal hypertension developed after splenic vein thrombosis/obstruction
• Formation of varices, with potential for massive upper GI bleeding
• Most common cause = chronic pancreatitis
• Incidence: 7% of patients with chronic pancreatitis
• Potentially curable by splenectomy
• Suspected in patients with bleeding esophageal varices, splenomegaly and normal liver function

Splenic Vein Thrombosis/Obstruction as a Cause of Sinistral Portal Hypertension

• In many patients, splenic vein obstruction is silent and undetected
• Likely related to many factors: compression of the veins by chronic inflammation (i.e. pseudocyst), stasis, intimal injury related to recurrent pancreatitis, systemic hypercoagulable state
• Leads to obstruction of splenic venous outflow. Venous blood from spleen returns to the heart via low-pressure collaterals (short gastric/gastroepiploic veins). This can be seen as gastric varices, and in some cases - esophageal varices.

References:

1. Loftus JP, Nagorney DM, Ilstrup D, Kunselman AR. Sinistral portal hypertension splenectomy or expectant management. Ann Surg 1993;217:35-40.

2. Sakorafas GH, Sarr MG, Farley DR, Farnell MB. The significance of sinistral portal hypertension complicating chronic pancreatitis. Am Surgeon 2000;179:129-133.