Residency · Residency · Anesthesiology

Perioperative Anticoagulant and Antiplatelet Management

Introduction

Managing anticoagulant and antiplatelet therapy in the perioperative period requires balancing the risk of thromboembolism from drug interruption against the risk of surgical bleeding from drug continuation. This decision-making process demands knowledge of drug pharmacology, patient-specific thrombotic risk, procedure-specific bleeding risk, and evidence-based bridging strategies. Poor management can result in devastating stroke, stent thrombosis, pulmonary embolism, or catastrophic surgical hemorrhage.

Antiplatelet Agents

Aspirin (Cyclooxygenase Inhibitor)

Aspirin irreversibly inhibits COX-1, blocking thromboxane A2-mediated platelet aggregation for the platelet lifespan of 7 to 10 days. Perioperatively, aspirin should be continued for patients with coronary stents (especially within 6 weeks of bare-metal stent placement or 6 months of drug-eluting stent placement), as well as for most cardiac surgery, carotid endarterectomy, and vascular procedures. It should be held 7 days before procedures with very high bleeding risk in closed spaces (intracranial, spinal canal, posterior eye chamber) if thrombotic risk permits. For patients taking aspirin for primary prevention without stents or prior cardiovascular events, discontinuation is generally safe.

P2Y12 Receptor Inhibitors

Dual antiplatelet therapy (DAPT) with aspirin plus a P2Y12 inhibitor is mandatory after coronary stent placement. Premature DAPT discontinuation is the strongest risk factor for stent thrombosis, which carries 20 to 40% mortality. Cangrelor is an intravenous, ultra-short-acting agent that can be used as a bridge for patients who must stop oral P2Y12 inhibitors but need continued antiplatelet coverage.

Glycoprotein IIb/IIIa Inhibitors

Eptifibatide and tirofiban are reversible agents that should be held 4 to 8 hours before surgery, while abciximab is irreversible and should be held 48 hours. These agents are primarily used in the acute coronary syndrome setting.

Anticoagulant Agents

Warfarin

Warfarin is a vitamin K antagonist that inhibits factors II, VII, IX, and X as well as proteins C and S. Its half-life is 36 to 42 hours, with the therapeutic effect lasting 4 to 5 days after discontinuation. Warfarin should be held 5 days before surgery, with INR confirmed to be less than 1.5 on the day of surgery. Reversal options include vitamin K (1 to 10 mg PO or IV, taking 12 to 24 hours for effect), FFP (immediate but temporary), and 4-factor PCC (preferred for urgent reversal at 25 to 50 units/kg).

Direct Oral Anticoagulants (DOACs)

Renal function is particularly important for dabigatran, which is 80% renally cleared; the hold period should be extended to 4 to 5 days if creatinine clearance is less than 50 mL/min. Specific reversal agents include idarucizumab (Praxbind) for dabigatran and andexanet alfa for factor Xa inhibitors. Four-factor PCC is an alternative for Xa inhibitor reversal. The PAUSE trial demonstrated that a simple perioperative management strategy of holding based on half-life, without bridging and without coagulation testing, is safe for patients on DOACs undergoing elective procedures.

Unfractionated Heparin (UFH)

UFH has an IV half-life of 60 to 90 minutes, and the IV infusion should be stopped 4 to 6 hours before surgery. Reversal is achieved with protamine sulfate at 1 mg per 100 units of heparin given in the last 2 to 3 hours. Monitoring uses aPTT or anti-Xa levels.

Low Molecular Weight Heparin (LMWH)

Enoxaparin at therapeutic doses should be held 24 hours before surgery, and prophylactic doses should be held 12 hours before surgery. Protamine partially reverses LMWH (approximately 60%), and andexanet alfa may have a role. For neuraxial anesthesia timing, ASRA guidelines specify that prophylactic doses should be held 12 hours before needle placement and restarted 4 hours after, while therapeutic doses should be held 24 hours before needle placement and restarted 4 hours after.

Bridging Anticoagulation

Indications for Bridging (Warfarin Patients)

High thrombotic risk patients who should receive bridging with LMWH or UFH include those with mechanical mitral valves, mechanical aortic valves with additional risk factors, recent venous thromboembolism (within 3 months), severe thrombophilia (antiphospholipid syndrome, protein C or S deficiency), and CHA2DS2-VASc score of 7 or higher with additional risk factors.

Low thrombotic risk patients who should not be bridged include those with bioprosthetic valves, atrial fibrillation with CHA2DS2-VASc of 4 or less, and VTE more than 12 months ago.

The BRIDGE trial demonstrated that forgoing bridging in atrial fibrillation patients on warfarin was noninferior for thromboembolism and resulted in significantly less major bleeding.

DOACs: No Bridging

DOACs should not be bridged. Their short half-lives allow reliable offset and rapid resumption, and bridging adds bleeding risk without benefit, as confirmed by the PAUSE trial.

Neuraxial Anesthesia and Anticoagulation (ASRA Guidelines)

Key Intervals

The consequences of epidural hematoma are catastrophic, potentially causing paraplegia, so clinicians should err on the side of longer intervals when uncertain. Catheter removal carries the same risk as placement, and the same intervals apply.

Procedure-Specific Bleeding Risk

Low Bleeding Risk (Consider Continuing Anticoagulation)

Low bleeding risk procedures include dental procedures, cataract surgery, minor dermatologic procedures, pacemaker or ICD implantation (continuing warfarin per the BRUISE CONTROL trial), and endoscopy without biopsy.

High Bleeding Risk (Hold Anticoagulation)

High bleeding risk procedures include intracranial surgery, spinal surgery, major abdominal or thoracic surgery, joint replacement, and procedures with potential for bleeding into closed spaces.

Postoperative Resumption

Antiplatelet agents are resumed as soon as surgical hemostasis is adequate, usually within 24 hours. Warfarin is resumed on the evening of surgery or postoperative day 1, keeping in mind that it takes 3 to 5 days to reach therapeutic effect. DOACs are resumed 48 to 72 hours after high-bleeding-risk surgery and 24 hours after low-bleeding-risk surgery, with the important caveat that DOACs reach full effect within hours of the first dose. If bridging is used, therapeutic LMWH is restarted 48 to 72 hours postoperatively for high-bleeding-risk procedures.

Key Clinical Pearls

DAPT should never be discontinued prematurely after coronary stenting; the risk of stent thrombosis is far greater than most surgical bleeding risks. The BRIDGE trial showed that most atrial fibrillation patients on warfarin do not benefit from bridging, and forgoing bridging reduces bleeding without increasing thromboembolism. DOACs should not be bridged because their pharmacokinetics allow a simple hold-and-resume strategy, as demonstrated by the PAUSE trial. When in doubt about neuraxial timing, the most conservative interval should be used because epidural hematoma is a devastating complication. Complex anticoagulation management decisions should always involve the prescribing cardiologist or hematologist.

References

1. Douketis JD, Spyropoulos AC, Kaatz S, et al. Perioperative bridging anticoagulation in patients with atrial fibrillation (BRIDGE trial). N Engl J Med. 2015;373(9):823-833.
2. Douketis JD, Spyropoulos AC, Duncan J, et al. Perioperative management of patients with atrial fibrillation receiving a direct oral anticoagulant (PAUSE trial). JAMA Intern Med. 2019;179(11):1469-1478.
3. Horlocker TT, Vandermeuelen E, Kopp SL, et al. Regional anesthesia in the patient receiving antithrombotic or thrombolytic therapy: ASRA evidence-based guidelines (4th edition). Reg Anesth Pain Med. 2018;43(3):263-309.
4. Rossini R, Musumeci G, Visconti LO, et al. Perioperative management of antiplatelet therapy in patients with coronary stents undergoing cardiac and non-cardiac surgery. Can J Cardiol. 2015;31(4):442-449.

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