In a patient presenting for neurologic surgery, which of the following times would be MOST appropriate for administering chemoprophylaxis (using antiplatelet or antithrombotic agents) for venous thromboembolism (VTE)?

  • (A) Two hours prior to the surgical procedure
  • (B) 24 hours after the end of the surgical procedure
  • (C) 96 hours after the surgical procedure
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Venous thromboembolism (VTE) in neurosurgical patients may be reduced or prevented using mechanical methods and chemoprophylaxis. Early postoperative ambulation is also effective for preventing VTE; however, this is often difficult in the neurosurgical population. Preoperative chemoprophylaxis with antiplatelet and antithrombotic agents adds a risk of bleeding that is unacceptable for patients undergoing craniotomy and spine surgery because bleeding in a closed space may increase pressure around vital neurologic structures.

Patients undergoing craniotomy have a risk of VTE of 1.7%-6.7% when mechanical prophylaxis is instituted. This high rate is attributed to immobility occurring after the surgical procedure because of altered neurologic status, paresis, or long and complicated procedures. In contrast, the risk of VTE with spine surgery is low (<1%). Current VTE recommendations for low-risk procedures (spine), moderate-risk procedures (craniotomy without malignancy), and high-risk procedures (intracranial hemorrhage, complex spine, craniotomy with malignancy) all include intraoperative and postoperative mechanical prophylaxis. Chemoprophylaxis should be instituted within 72 hours postoperatively and should be continued until the patient is ambulatory. The risk of VTE increases if chemoprophylaxis is delayed longer than 72 hours after the surgery ends.

Of the answer choices provided, 24 hours is the best option, although anytime within 72 hours after the end of the surgical procedure is appropriate for administration of chemoprophylaxis.

Answer: B