Prediction of the therapeutic effects of anticoagulation for recent portal vein thrombosis: a novel approach with contrast-enhanced ultrasound.

OBJECTIVE: To examine whether intra-thrombus enhancement on contrast-enhanced sonograms can predict the recanalization by anticoagulation for recent portal thrombosis.

METHODS: This prospective study included 10 patients with a recent portal thrombosis and 20 controls (10 cirrhosis patients and 10 healthy subjects, all without thrombosis). The diagnosis of thrombosis was based on clinical and ultrasound findings. Pre-anticoagulation intra-thrombus enhancement on the contrast-enhanced sonogram was examined with respect to the post-anticoagulation results or portal enhancement in controls.

RESULTS: Complete recanalization was obtained in 4 patients with positive intra-thrombus enhancement. However, in 4 other patients who had a thrombosis showing positive enhancement concurrent with one showing negative enhancement, anticoagulation recanalized the former and failed to recanalize the latter. Mean onset time of contrast enhancement measured from the beginning of hepatic arterial enhancement was significantly longer in the thrombus (6.6 ± 4.3 s, 3-16 s) than in the portal vein of controls (cirrhosis, 4.3 ± 1.4 s, 2-8 s, P = 0.0035; healthy subjects, 2.4 ± 0.6 s, 1-3 s, P < 0.0001). Anticoagulation failed to achieve recanalization in 2 patients with negative intra-thrombus enhancement. Sensitivity and specificity of contrast enhancement for the prediction of post-treatment recanalization was 100%.

CONCLUSIONS: Intra-thrombus positive enhancement demonstrated on contrast-enhanced sonograms has promise as a successful predictor of recanalization for the recent portal thrombosis.