Cancer Patients Requiring Interruption of Long-Term Anticoagulant Therapy: The Use of Fixed Sub-Therapeutic Doses of Low-Molecular Weight Heparin

We tested the efficacy and safety of fixed doses of Low-Molecular Weight Heparin (LMWH) in cancer patients requiring interruption of Vitamin-k Antagonist (VKA) because of invasive procedures (defined as major and non major surgery) or chemotherapy inducing platelets depletion. Methodology. Cancer patients were defined to be at high (atrial fibrillation [AF] with previous stroke, prosthetic mitralic valves and venous thromboembolism [VTE] lasting < 3months) or low risk of thrombosis (AF without previous stroke, VTE lasted > 3 months, and prosthetic aortic valves). They discontinued VKA 5 + 1days before surgery or chemotherapy; in those at low-risk for thrombosis, LMWH was given at a prophylactic dosage of 3.800 U.I. (nadroparin) or 4.000 U.I. (enoxaparin) anti-FXa once daily the night before the procedure or the beginning of chemotherapy. In patients at high-risk for thrombosis, LMWH was started early after VKA cessation (when an INR < 1.5) and given at fixed sub-therapeutic doses (3.800 or 4.000 UI anti-FXa twice daily) until procedure or beginning of chemotherapy. In patients undergoing procedures, LMWH was reinitiated 12 hours after procedure while VKA the day after; in patients receiving chemotherapy, LMWH was reinitiated 12 h after a stable platelet count > 30.000 mmc³ and VKA 12 h after a stable platelet count > 50.000 mmc³. Heparin was continued until a therapeutic INR value was reached. The primary efficacy endpoints were the incidence of thromboembolism and major bleeding from VKA suspension to 30 + 2 days post-procedure or next chemotherapy. Results. A total of 156 patients (68, 53.9% at low-risk and 58, 46.1% at high-risk for thrombosis) were enrolled (Table 1); 44 (28.2%) underwent major surgery, 53 (33.9%) non-major surgery and 29 (18.5%) chemotherapy. Overall, thromboembolic events occurred in 5 patients (3.2%, 95% confidence intervals 0.5–5.9), 4 belonging to high-risk and 1 to low-risk group. Overall, major bleeding occurred in 5 patients (3.2%, 95 CI 0.5–5.9), all belonging to high-risk group (3 during major surgery and 2 during chemotherapy). The mean time of anticoagulation with LMWH was 7.5 days in patients underwent procedures and 13.2 days in those who received chemotherapy. Conclusion. LMWH given at fixed sub-therapeutic doses appears to be a feasible and relatively safe approach for bridging therapy in chronic anticoagulated cancer patients requiring VKA interruption.

No relevant conflicts of interest to declare.