Obstetric Postoperative Venous Thromboembolism Prophylaxis Guidelines

Venous Thromboembolic Events (VTE), the collective term for Deep Venous Thrombosis (DVT) and Pulmonary Embolism (PE), are major postoperative concerns. A cesarean section approximately doubles the risk of VTE compared to a vaginal delivery1. VTE is the sixth most common cause of pregnancy related deaths, responsible for 9.6% of pregnancy related deaths in the US from 2006-20102. Observational studies estimate the risk of VTE from cesarean as rare, from < 1/1,000 – 18/1,000.

The six weeks following delivery appear to be the time of maximal risk, five times greater than in pregnancy. Pregnancy specific changes that increase VTE risk include: hypercoaguability, increased venous stasis, decreased venous outflow, compression of the inferior vena cava, and decreased mobility3. Pregnancy related changes lead to shorter half lives and lower peak plasma concentrations of heparin compounds4.

ACOG recommends that all women undergoing cesarean delivery receive mechanical prophylaxis5. This has been identified as a means of systematically reducing maternal mortality in the US, and is supported by decision and economic analyses6-8. Unfortunately, a recent review showed that > 50 % women are receiving no prophylaxis9.

Mechanical Prophylaxis

Sequential Compression Devices (SCD’s) prevent venous stasis and are as effective as heparin preparations. They should be placed and activated, prior to anesthesia, used continuously until fully ambulatory, and (ideally) until time of discharge. A recent study showed only 58% of patients are compliant with SCD use4. Consider using pharmacologic prophylaxis if patient compliance is a concern. Do not place SCD’s on a limb where an acute DVT is suspected.

Pharmacologic Prophylaxis

When indicated, pharmacologic prophylaxis should be initiated 24hrs after c/s, unless otherwise specified by the attending surgeon. Patients with significant intraoperative or postoperative bleeding may have their anticoagulation held at the discretion of the attending surgeon. If an acute VTE develops, therapeutic dosing is required.

Unfractionated Heparin (UFH) is the most extensively studied method. UFH binds to antithrombin and enhances its activity. Use for more than 4 days requires monitoring of platelets as 6% will develop heparin induced thrombocytopenia (HIT). Other potential adverse events include osteoporosis and bleeding.

Low Molecular Weight Heparin (LMWH) has greater availability, more predictable pharmacokinetics, rare HIT, and less risk of osteoporosis with long-term use. LMWH inactivates factor Xa.

Adapted from: Bates SM, Greer IA, Middeldorp A, et al. VTE, Thrombophilia, Antithrombotic Therapy, and Pregnancy. 9th ed: American College of Chest Physicians evidence-based clinical practical guidelines. Chest 2012; 141:e691s-e736s.

References

1. Hirsh J, Hoak J. Management of deep vein thrombosis and pulmonary embolism. A statement for healthcare professionals. Council on Thrombosis (in consultation with the Council on Cardiovascular Radiology), American Heart Association. Circulation 1996;93:2212-45.
2. Clarke-Pearson DL, Synan IS, Colemen RE, Hinshaw W, Creasman WT. The natural history of postoperative venous thromboemboli in gynecologic oncology: a prospective study of 382 patients. American journal of obstetrics and gynecology 1984;148:1051-4.
3. Geerts WH, Pineo GF, Heit JA, et al. Prevention of venous thromboembolism: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. Chest 2004;126:338S-400S.
4. Brady MA CA, Kai IC, Straight C. Sequential Compression Device Compliance in Postoperative Obstetric and Gynecology Patients. Obstetrics and gynecology 2014;0:7.
5. James A, Committee on Practice B-O. Practice bulletin no. 123: thromboembolism in pregnancy. Obstetrics and gynecology 2011;118:718-29.
6. Clark SL, Belfort MA, Dildy GA, Herbst MA, Meyers JA, Hankins GD. Maternal death in the 21st century: causes, prevention, and relationship to cesarean delivery. American journal of obstetrics and gynecology 2008;199:36 e1-5; discussion 91-2 e7-11.
7. Quinones JN, James DN, Stamilio DM, Cleary KL, Macones GA. Thromboprophylaxis after cesarean delivery: a decision analysis. Obstetrics and gynecology 2005;106:733-40.
8. Casele H, Grobman WA. Cost-effectiveness of thromboprophylaxis with intermittent pneumatic compression at cesarean delivery. Obstetrics and gynecology 2006;108:535-40.
9.  Friedman AM, Ananth CV, Lu YS, D’Alton ME, Wright JD. Underuse of postcesarean thromboembolism prophylaxis. Obstetrics and gynecology 2013;122:1197-204.
10. Bates SM, Greer IA, Middeldorp S, et al. VTE, thrombophilia, antithrombotic therapy, and pregnancy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest 2012;141:e691S-736S.
11. Overcash RT, Somers AT, LaCoursiere DY. Enoxaparin dosing after cesarean delivery in morbidly obese women. Obstetrics and gynecology 2015;125:1371-6.