Dose escalation of low molecular weight heparin to manage recurrent venous thromboemblic events despite systemic anticoagulation in cancer patients

Abstract

e20580 Background: Cancer patients with venous thromboembolism (VTE) are at high risk of recurrent VTE. The rate of recurrent VTE ranges from 9 to 17% despite therapy with low molecular weight heparins (LMWH) or vitamin K antagonists (VKA) respectively. To date, no published evidence is available to guide treatment of cancer patients with recurrent VTE. We sought to evaluate the benefit and risk of LMWH dose escalation in cancer patients with recurrent VTE. Methods: Retrospective cohort study was conducted in consecutive cancer outpatients referred for management of an objectively confirmed, symptomatic, recurrent VTE while receiving an anticoagulant. Patients were treated with either dose escalation of weight-adjusted LMWH in patients already anticoagulated with LMWH or initiation of a therapeutic dose LMWH in patients who were taking a VKA. All patients were followed for a minimum of 3 months after the index recurrent VTE. Results: Seventy cancer patients with a recurrent VTE despite ongoing anticoagulation were included. The median time between the initial VTE to the index recurrence was 3.5 months (range 0.3 to 193 months). At the time of the recurrence, 67% of patients were on LMWH, while 33% were on VKA. Following the treatment with either dose escalation or initiation of LMWH, a total of 6 patients (8.6%; 95% confidence interval (CI): 4.0% to 17.5%) had a second recurrent VTE during the three-month follow-up period, at an event rate of 9.9 per 100 patient-years (95% CI: 2.0 to 17.8). The median time between the index and second recurrent VTE was 1.9 months (range 0.6 to 3.0 months). One patient (1.4%; 95% CI: 0.3% to 7.7%), or 1.6 per 100 patient-years (95% CI: 0.0% to 4.8%) of follow-up, had a major bleeding event. The median time between the index recurrent VTE to death was 11.4 months (range 0 to 83.9 months). Conclusions: Patients with recurrent VTE have a poor prognosis. Escalating the dose of LMWH can be effective for treating cases that are resistant to standard, weight-adjusted doses of LMWH or a VKA. [Table: see text]