Impact of thrombocytopenia on bleeding and thrombotic outcomes in adults with cancer-associated splanchnic vein thrombosis

Malignancy is a risk factor for splanchnic vein thrombosis (SpVT). Data on the natural history of cancer-associated SpVT are limited. This was a single-center, retrospective cohort study of 581 adult patients with cancer and SpVT. We aimed to characterize the impact of thrombocytopenia on major bleeding and progression or recurrence of SpVT within 1 year of an initial cancer-associated SpVT diagnosis. Baseline thrombocytopenia (platelet <100 × 10³/μL within 15 days of SpVT diagnosis) was present in 39.5% of patients. A total of 39.2% of patients received therapeutic anticoagulation within 2 weeks of an SpVT diagnosis. The cumulative 1-year incidence of major bleeding was 10.7% (95% confidence interval [CI], 8.2-13.2) and 16.2% (95% CI, 13.2-19.2) for SpVT recurrence/progression. In the multivariable regression analysis, therapeutic anticoagulation was associated with increased major bleeding (adjusted risk ratio [aRR], 1.74; 95% CI, 1.08-2.81) and decreased progression/ recurrence of SpVT (aRR, 0.55; 95% CI, 0.35-0.86). Baseline thrombocytopenia was not independently associated with either major bleeding (aRR, 0.76; 95% CI, 0.43-1.34) or progression/recurrence of SpVT (aRR, 1.14; 95% CI, 0.73-1.78). A secondary analysis using inverse probability of treatment weighting with propensity scores for baseline thrombocytopenia corroborated that patients with thrombocytopenia did not have an increased bleeding risk (adjusted hazard ratio [aHR], 0.81; 95% CI, 0.48-1.39). The multivariable analysis in which platelets were treated as a time varying covariate also did not reveal an association with major bleeding (aHR, 0.89; 95% CI, 0.55-1.45). Bleeding and thrombosis progression were frequent in patients with cancer-associated SpVT. Anticoagulation was associated with increased major bleeding and decreased thrombotic progression; thrombocytopenia did not impact the outcomes.