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Interruption or continuation of antithrombotic therapy in perioperative patients?
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Interruption or continuation of antithrombotic therapy in perioperative patients?

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Ariel L. Clark, PharmD

Too often, clinicians question whether they are making the right decision about a patient’s anticoagulation therapy with planned, nonemergent surgical procedures. Clinicians must determine when to interrupt the regimen to protect patients from unnecessary post-procedural bleeding, for how long, and if bridging is necessary. Until now, guidance has not been inclusive to this wide range of possible situations.

In their August 11, 2022, update to the clinical practice guideline on the perioperative management of antithrombotic therapy, the American College of Chest Physicians (CHEST) aimed to expand recommendations to better capture the variety of instances—from 11 to 43 PICO (patient/problem/population, intervention, comparison, outcome) questions—when practitioners must decide between interruption versus continuation or interruption and bridging of antithrombotics.

These guidelines are intended to provide clinicians with a frame of reference to help them make decisions for their patients’ individual care.

Vitamin K antagonists

Recommendations from CHEST for patients receiving a vitamin K antagonist (e.g., warfarin) with a low-to-moderate bleed risk and high bleed risk are the same in cases when the planned operation is likely to result in bleeding.

The executive summary of the recommendations suggest discontinuation of the drug 5 days prior to the day of the procedure, with some exceptions in patient-specific cases such as in older adults, and a restart within 24 hours afterward at the same dose.

Direct oral anticoagulants

CHEST exclusively recommends interruption of therapy in patients on direct-acting oral anticoagulant (DOAC) therapy in the update. Individual drugs in this class of medication have variable half-lives and the updated clinical practice guidance suggests that each should be assessed uniquely for when to interrupt and when to restart therapy for elective procedures.


Drugs in the antiplatelet class include aspirin, clopidogrel, and prasugrel. CHEST recommends that clinicians almost exclusively interrupt therapy of these before surgery, with one exception: in patients who are preparing for an elective, noncardiac procedure at a low-bleed risk or for a coronary artery bypass graft procedure.

In these cases, the aspirin regimen can continue uninterrupted. Similar to DOACs, each antiplatelet drug has a unique interruption date prior to the procedure and restart date after surgery.

Clinicians should also note that in cases in which patients are on dual-antiplatelet therapy, such as when a coronary stent is placed, the guidance says to either continue both drugs for an elective procedure or to interrupt one of them prior to the procedure based on the individual patient’s bleed risk. When the stent(s) were placed within the last 3 to 12 months, the P2Y12 inhibitor should be stopped.


In general, the updated guidance suggests against the use of either low-molecular weight heparin (LMWH) or unfractionated heparin (UFH) bridging except in specific patient cases, including when patients have a high risk for thromboembolism, had a recent stroke or ischemic attack, had a prior perioperative clotting event, or have a CHA2DS2-VASc score greater than 7.

When bridging is indicated, the updated CHEST guidelines suggest stopping intravenous UFH more than 4 hours prior to surgery and restarting more than 24 hours after surgery. In LMWH patient cases, the dose prior to surgery should be more than 24 hours before at half the dose and restarted at least 24 hours after surgery.

Minor procedures

In cases of minor procedures—such as dental procedures—or ones for which postoperative bleeding is expected to be minimal, the updated guidance suggests continuation of therapeutic warfarin, DOACs, and antiplatelets over interruption of therapy.

Procedural bleed risk

With any surgical procedure, there is at least some level of risk for bleeding. However, some procedures have a higher bleeding risk than others.

Procedures with a high bleed risk include any major surgery, including orthopedic or thoracic procedures, biopsies or resections, or other surgeries in which the total procedure time exceeds 45 minutes.

CHEST suggests that clinicians should refer to the Risk Stratification for Procedural Bleed Risk Based on the International Society on Thrombosis and Haemostasis, Inc. (ISTH) Guidance Statements.

As pharmacy professionals play their part in helping to avoid unnecessary and potentially dangerous bleeds in patients, they must also take an active role in assuring medications are restarted and bridged appropriately.

These updated guidelines can help providers determine what’s right for their patients. ■



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