Development of Thrombus in the Major Systemic and Portal Veins after Balloon-Occluded Retrograde Transvenous Obliteration for Treating Gastric Variceal Bleeding: Its Frequency and Outcome Evaluation with CT

Purpose: To investigate the frequency and outcome of the thrombus that developed in the major systemic and portal veins after balloon-occluded retrograde transvenous obliteration (BRTO) by comparing the computed tomographic (CT) scans obtained before and after BRTO treatment. Materials and Methods: Sixty patients with liver cirrhosis who underwent BRTO to treat gastric variceal bleeding were included in this study. The pre- and postprocedural CT scans in these patients were retrospectively compared to evaluate thrombus development in the major systemic and portal veins after BRTO. Thrombus was classified as having a high attenuation (ie, containing iodized oil), combined attenuation, or low attenuation. The outcome of the thrombus that developed in those veins after BRTO was evaluated by reviewing the serial follow-up CT scans. Results: After BRTO, 14 thrombi developed in 13 systemic and portal veins of nine of the 60 patients (15%). Eleven of the 14 thrombi had high attenuation, two thrombi had low attenuation, and one thrombus had a combined attenuation. The 13 affected veins included six splenic veins, four left renal veins, and three main portal veins. On the serial follow-up CT scans (range of the follow-up period, 5-25 months), all 11 high-attenuation thrombi were completely resolved without sequelae in the affected veins. One of the two low-attenuation thrombi disappeared with severe slitlike collapse of the affected left renal vein; the other low-attenuation thrombus had progressed and it caused complete occlusion of the affected main portal vein. One thrombus with a combined attenuation was almost completely resolved without sequelae in the affected splenic vein, despite the transient enlargement of the low-attenuation component. Conclusions: In this study, the frequency of thrombus development in the major systemic and portal veins after BRTO was 15%. Although iodized oil deposited in those veins appears to be of no great importance, the low-attenuation thrombus can be associated with occlusion of the affected vein. These tendencies, however, require validation in a larger series.