The incidence and natural history of thrombus in the portal vein following distal splenorenal shunt.

The incidence of thrombus formation in the portal vein following distal splenorenal shunt was 4% occlusive and 14% nonocclusive from 1974 to 1977, and 6% occlusive and 22% nonocclusive in 1980. The increased incidence was probably due to more aggressive ligation of collaterals on the portal vein. Ten patients with this complication were evaluated prospectively with clinical and biochemical parameters, angiography, and nutrient hepatic perfusion. In this group, one thrombus was occlusive immediately after operation, and nine were nonocclusive: eight of the latter resolved by six months, but one progressed to total thrombosis. There were no demonstrable adverse clinical or biochemical sequelae. Angiography showed continuing portal perfusion in the face of nonocclusive thrombus, but at six months there was increased collateral formation and significant (p less than 0.05) reduction in portal vein diameter, from 20 +/- 4 mm to 14 +/- 5 mm. Nutrient hepatic perfusion at six months, 896 +/- 257 ml/min, was not significantly different from that seen prior to operation, 848 +/- 92 ml/min. It is concluded that the natural history of nonocclusive portal vein thrombus after distal splenorenal shunt is resolution, and management should be expectant.