Warfarin

Warfarin management requires a procedure-specific assessment of bleeding and thromboembolic risk. The same principles are generally applied to other vitamin K antagonists such as acenocoumarol, which is commonly prescribed in India, though the pharmacokinetics differ.

Is interruption needed?

Some minor procedures can be performed without interrupting warfarin, for example selected minor dental, dermatological and cataract procedures, and cardiac device implantation, according to CHEST guidance and local practice.

Interruption

When warfarin interruption is required, CHEST 2022 suggests stopping warfarin at least 5 days before the procedure.

A preoperative INR helps assess residual anticoagulant effect. An unexpectedly elevated result needs review in relation to the procedure, urgency and local protocol; vitamin K use is a separate clinical decision.

Bridging

CHEST 2022 recommends against routine heparin bridging for atrial fibrillation and suggests against bridging for mechanical valves or VTE when warfarin is interrupted. AHA/ACC 2024 allows bridging in selected patients at particularly high thrombotic risk. These recommendations have different scopes and evidence grades; they are not a reason to apply one rule to every valve or recent thrombotic event. Specialist planning is particularly important in very high-risk situations.

The indication, INR and procedure-specific bleeding risk inform the individual plan. Very high thrombotic-risk situations require specialist planning. CHEST and cardiovascular guidance should be interpreted in their respective clinical contexts.

Restarting

Planning includes resumption as well as interruption. The timing depends on haemostasis, bleeding risk and the ability to take treatment. Where bridging is selected after individual assessment, the plan also specifies when parenteral anticoagulation may resume and when it can end as warfarin becomes therapeutic.

Regional anaesthesia

The ASRA fifth-edition guidance addresses the additional requirements of neuraxial and deep regional procedures. A surgical interruption plan alone is insufficient.

Before a block: assessment includes the interruption interval and confirmation that the INR meets the applicable regional-anaesthesia recommendation.
A falling INR after recent warfarin cessation does not necessarily describe recovery of every vitamin K-dependent clotting factor.
Indwelling catheters: removal timing, INR interpretation and subsequent neurological observation need the complete ASRA recommendation and an agreed local plan. This summary does not specify a universal 24-hour endpoint for monitoring.
Monitoring during epidural analgesia may include serial INR assessment and neurological examination, with an analgesic regimen that permits meaningful assessment of sensory and motor function.

Unexpected weakness, sensory change or other concern about neuraxial bleeding requires urgent clinical evaluation. The guideline provides the detailed catheter and monitoring recommendations.