Decreased portal vein velocity is predictive of the development of portal vein thrombosis: A matched case-control study

Background & Aims: Portal vein thrombosis (PVT) in cirrhosis may lead to hepatic decompensation and increased mortality. We aimed to investigate if decreased portal vein (PV) velocity is associated with future PVT. Methods: Data on adult patients with cirrhosis and PVT between January 1, 2005 and July 30, 2015 were obtained. Cases with PVT were matched by age, gender and Model for End-stage Liver Disease (MELD) score to corresponding controls without PVT. Cox proportional hazards models, receiver operator curves and Kaplan Meier curves were constructed. Results: One hundred subjects (50 matched pairs) with mean age 53.8±13.1 y and MELD score 14.9±5.5 were included in our analysis. Sixty-four percent were male and 76% were Child-Turcotte-Pugh Class A or B. Baseline characteristics (prior to development of PVT) were similar, except for baseline PV velocity (16.9 cm/s, 95% CI 13.9-20.0 PVT vs 25.0, 95% CI 21.8-28.8 no PVT, P<.001). 30 PVT subjects had PV velocity <15 cm/s compared to five without PVT (P<.001). On adjusted multivariable analysis, PV velocity was the strongest independent risk factor predicting PVT development (HR 0.86, 95% CI 0.80-0.93). The predictive value for PVT development was greatest for flow <15 cm/s (c-statistic 0.77). PV velocity <15 cm/s had a highly significant association with future PVT (HR 6.00, 95% CI 2.20-16.40, P=<.001). Conclusions: Decreased PV velocity is associated with increased risk of future PVT. Patients with cirrhosis and decreased PV velocity are a high-risk subgroup that warrants further investigation with prospective study.