Splanchnic vein thrombosis: Impact on survival outcomes in younger patients with PV or ET

Splanchnic vein thrombosis (SVT) occurs in approximately 5% of patients with myeloproliferative neoplasms (MPN) and development is commonly associated with the Janus kinase 2^V617F driver mutation either at diagnosis or follow-up.¹

Here, we summarize a study published by Garrote et al.¹ in Annals of Hematology on the role of SVT and genomic characteristics in the outcomes and survival of patients with polycythemia vera and essential thrombocythemia.

Patient population¹

• A cohort of 255 patients aged 37–60 years were included:
  • 90 patients with SVT, with 59 of those presenting at MPN diagnosis, 10 before diagnosis, and 21 during follow-up.
  • 165 patients with MPN but without SVT as a control group
• Localization of SVT:
  • Splenoportal area, 64%
  • Hepatic vein (Budd-Chiari syndrome), 32%
  • Both locations, 3%
• The incidence of heterozygous Janus kinase 2 mutation was more common in patients with SVT compared with the control group (87% vs 69%, respectively; p < 0.05).

Key findings¹

• Compared with the control cohort, patients with SVT presented with a higher risk of:
  • Venous rethrombosis; hazard ratio (HR) 3.0 (95% confidence interval [CI], 1.5–6.0; p = 0.003) and after correction by age; HR 1.1, (95% CI, 1.08–1.15; p < 0.001)
  • Total thrombosis; HR 3.2, (95% CI, 1.6–6.4; p = 0.001) and after correction by age; HR 1.03 (95% CI, 0.99–1.06; p = 0.07)
  • Thrombosis at 10 years was 27% and 8%, respectively (p = 0.001).
• Patients with SVT also presented with:
  • lower rates of event-free survival; HR 3.0 (95% CI, 1.9–4.8; p < 0.001); and
  • association between molecular high-risk status and an increased risk of venous rethrombosis; HR 5.8 (95% CI, 1.4–24.0, p = 0.01).

• Patients who developed SVT during the follow-up period were more likely to be molecular high-risk than those with SVT present at diagnosis (52% vs 13%, respectively; p < 0.05).
• Median overall- and event-free survival was poorer in patients with SVT (Figure 1)

Figure 1. Median overall- and event-free survival in patients with or without SVT* 

EFS, event-free survival; OS, overall survival; SVT, splanchnic vein thrombosis.
*Data from Garrote, et al.¹