Natural history and clinical outcomes in patients with portal vein thrombosis by etiology: A retrospective cohort study.

Background: Portal vein thrombosis (PVT) is an unusual-site thrombosis commonly encountered in patients with malignancies, cirrhosis, and acute abdominal inflammatory conditions (AIC). Current recommendations suggest that anticoagulation may improve recanalization rates but there is limited information on venous thromboembolism (VTE) recurrence rates and whether the etiologies of PVT respond similarly with anticoagulation.

Objective: To characterize the natural clinical course and outcomes of patients diagnosed with PVT based on etiology.

Patients/methods: Patients with a diagnosis of PVT between 2005 and 2015 who were followed for at least one year and had revised imaging at 12 months ± 3 months were identified. Comorbidities, demographics, anticoagulation choice and clinical outcomes including VTE recurrence, cavernous transformation, PVT recanalization, progression and mortality were obtained.

Results: Of 698 patients diagnosed with PVT, 85 patients were evaluable according to criteria: 54 had cirrhosis (63.5%), 15 malignancy (17.6%) and 16 AIC (18.8%). Mean age was 55.6 ± 13.1 years. At presentation, 40% patients were symptomatic and 29.4% received anticoagulation. Patients with AIC were anticoagulated more frequently compared to those with malignancy or cirrhosis (87.5% vs. 33.3% vs. 11.1%). Overall, patients with cirrhosis had lower rates of PVT progression (0% vs. 13.3%, p = 0.02) and patients with AIC had higher rates of cavernous transformation compared to cirrhosis or malignancy-associated PVT (31.3% vs. 7.4% vs. 0%, p = 002). Among untreated patients, those with malignancy had significantly higher rates of VTE recurrence and PVT progression than patients with cirrhosis (20% vs. 4.2% and 20% vs. 0%).

Conclusions: The natural course of PVT differs among etiologies. In the absence of anticoagulation, patients with malignancy are more prone to VTE recurrence and PVT progression compared to patients with cirrhosis. Given the high rate of VTE recurrence at 12 months in patients with malignancy-associated PVT, anticoagulation should be considered for this group.