Recurrent venous thrombosis in myeloproliferative neoplasms: impact of cytoreductive control and antithrombotic strategy

Venous thromboembolism (VTE) may reveal myeloproliferative neoplasms (MPNs), yet the risk of recurrence under contemporary cytoreductive management remains uncertain. We assessed the incidence of recurrent VTE in the nationwide French cohort of patients with polycythemia vera or essential thrombocythemia who experienced a non-splanchnic VTE within 12 months prior to MPN diagnosis. Among 5,163 patients, 117 exhibited initial VTE of their MPN. With a median follow-up of 4.3 years (IQR 1.9–8.8), 13 recurrent VTE events occurred, yielding an incidence rate of 1.80 per 100 patient-years (95% CI 0.96–3.08). The 5-year cumulative incidence of recurrence was 6.36% (95% CI 0.73–11.66). Demographic characteristics, MPN subtype, and antithrombotic strategy were not significantly associated with recurrence. In contrast, achievement of an ELN-defined cytoreductive response was strongly associated with lower recurrence risk. The incidence rate was 0.25 per 100 patient-years in ELN responders versus 4.49 per 100 patient-years in non-responders (p < 0.001). All but one recurrent event occurred in patients who did not meet ELN criteria. Long-term anticoagulation was not associated with a statistically significant reduction in recurrence (2.24 vs 1.38 per 100 patient-years; p = 0.285). In conclusion, recurrent VTE after MPN-associated usual-site thrombosis was infrequent and predominantly observed in patients without effective cytoreductive control.