From the Guidelines
Heparin should be discontinued 4-6 hours before surgery for intravenous unfractionated heparin and 24 hours before surgery for low molecular weight heparin (LMWH). When considering the discontinuation of heparin before surgery, it is crucial to balance the risk of bleeding against the risk of thrombotic events.
- The American College of Chest Physicians guidelines, as outlined in the 2012 study 1, provide recommendations for the perioperative management of antithrombotic therapy.
- For patients receiving bridging anticoagulation with therapeutic-dose IV unfractionated heparin, stopping the medication 4-6 hours before surgery is recommended to minimize postoperative bleeding risk, as observed in observational studies 1.
- In contrast, for patients on low molecular weight heparin (LMWH), administering the last preoperative dose 24 hours before surgery is advised to reduce the risk of postoperative bleeding, based on the findings of observational studies 1.
- The timing of heparin discontinuation is influenced by the half-life of the medication, with unfractionated heparin having a shorter half-life of 60-90 minutes compared to LMWH's longer half-life of 4-7 hours.
- After surgery, heparin can typically be resumed 24 hours post-procedure for patients with low to moderate bleeding risk, as suggested by observational studies 1, while those with high bleeding risk may require a longer interval before resuming therapeutic-dose LMWH.
From the FDA Drug Label
2.6 Low-Dose Prophylaxis of Postoperative Thromboembolism The most widely used dosage has been 5,000 units 2 hours before surgery and 5,000 units every 8 to 12 hours thereafter for 7 days or until the patient is fully ambulatory, whichever is longer. The heparin should be discontinued when the patient is fully ambulatory, or after 7 days of therapy, whichever is longer, but the exact timing of discontinuation before surgery is 2 hours for the last dose of heparin when used for low-dose prophylaxis of postoperative thromboembolism 2.
From the Research
Discontinuation of Heparin Before Surgery
- The decision to discontinue heparin before surgery depends on various factors, including the type of surgery, the patient's condition, and the risk of bleeding or thrombosis.
- According to a study published in Haematologica 3, patients undergoing elective coronary artery bypass grafting (CABG) surgery were randomized to receive either unfractionated heparin (UFH) or enoxaparin until 12 hours before surgery.
- The study found that coagulation parameters increased significantly and similarly at 30 minutes and 6 hours with both treatments, but returned within the normal range at 12 hours.
- Another study published in the Journal of intensive care medicine 4 discussed the use of argatroban as an alternative to heparin in patients requiring extracorporeal membrane oxygenation (ECMO) support.
- However, this study did not provide specific guidance on when to discontinue heparin before surgery.
- A retrospective cohort analysis published in Annals of hematology 5 compared the effectiveness of argatroban and fondaparinux in the management of patients with isolated heparin-induced thrombocytopenia, but did not address the discontinuation of heparin before surgery.
- A study published in the European journal of biochemistry 6 is not relevant to the question of when to discontinue heparin before surgery, as it discusses the nuclear-magnetic-resonance study of aggregations and conformations of melanostatin and related peptides.
Timing of Heparin Discontinuation
- Based on the available evidence, it appears that heparin should be discontinued at least 12 hours before surgery, as shown in the study published in Haematologica 3.
- However, the optimal timing of heparin discontinuation may vary depending on the specific clinical situation and the type of surgery being performed.
- Further studies are needed to provide more specific guidance on when to discontinue heparin before surgery.