Pearls of Wisdom: Warfarin Management With Dental Surgery
Roger is a 72-year-old man who has been taking warfarin for 3 years because of atrial fibrillation (CHADS score 3). In the near future, he will be undergoing 2 dental extractions and the dentist has asked that you manage his warfarin for the procedure. His international normalized ratio (INR) has been stable at 2.2-2.6 for 12 months.
What should you do?
A. Stop warfarin 5 days before extractions; no bridge.
B. Stop warfarin 5 days before extractions; enoxaparin bridge.
C. Stop warfarin 5 days before extractions; clopidogrel bridge.
D. Continue warfarin and add topical prohemostatic agent.
What is the correct answer?
(Answer and discussion on next page)
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Answer: Continue warfarin and add topical prohemostatic agent.
According to the most recent guidelines from the American College of Chest Physicians, it is appropriate to continue vitamin K antagonists and manage potential bleeding with coadministration of a topical prohemostatic agent. Currently, the only topical prohemostatic agent available is tranexamic acid (Lysteda).
Potential Interactions with Warfarin Treatment
When Do You Start Warfarin Treatment and How Do You Monitor It?
Tranexamic acid is an antifibrinolytic (not to be confused with a procoagulant). When I first heard the moniker "antifirinolytic", I mistakenly thought that such an agent must be, like oral contracetpives, prothrombotic. In fact, instead of promoting coagulation/thrombosis, antifibrinolytics work by preventing the dissolution of established fibrin clots.
How does it work? Plasmin is the primary substance responsible for dissolving fibrin clots. Inhibition of plasminogen activator (the mechanism of action of tranexamic acid) prevents the conversion of plasminogen into plasmin, thereby blocking fibrin clot dissolution, and reducing active bleeding.
What is Tranexamic Acid?
A randomized, double-blind, placebo-controlled trial of 94 patients, all of whom were taking warfarin, were randomized to either 10 ml of tranexamic acid solution (4.8%) or to placebo following dental procedures.1 Patients using the tranexamic acid performed mouthwash with the solution immediately after surgery and for 2 minutes 4 times daily over 7 days.
Overall, none of the 46 patients using tranexamic acid and 10 of the 47 patients using placebo experienced significant bleeding requiring treatment.
The CRASH Trial
In another randomized, double-blind, placebo-controlled trial—the Clinical Randomization of an Antifibrinolytic in Significant Hemorrhage (CRASH-2) study—researchers followed 20,211 trauma patients assigned to either tranexamic acid IV (1 g load + 1 g 8 hour infusion) or placebo.2 The hypothesis of the trial was that administration of an agent to reduce fibrinolysis in persons who had suffered major trauma with evidence of significant internal bleeding would reduce additional bleeding.
Overall, individuals seen within 1 hours of their injury who were given tranexamic acid were 13% less likely to die due to bleeding than individuals given placebo. For further results, see Table 1.
Table 1: Tranexamic Acid Vs Placebo: All-Cause Mortality
Since the idea that an antifibrinolytic is not procoagulant is so counter-intuitive, let’s also look at the incidence of thrombotic events in patients treated with tranexamic acid: patients given tranexamic acid were 36% less likely to have myocardial infarction, 14% less likely to have a stroke, and 2% less likely to have a blood clot in the leg. Furthermore they were 2% less likely to require a blood transfusion than patients given placebo.
CRASH-2 Thrombotic Outcomes and Transfusions
What’s the “Take-Home?”
All of these results point to the message that tranexamic acid is not something that will increase your risk of clots. Tranexamic acid topical solution that is effective for controlling bleeding in patients taking warfarin for atrial fibrillation who need to undergo dental procedures.
1. Wahl MJ. Dental Surgery in Anticoagulated Patients. Arch Intern Med. 1998;158:1610-1616.
2. CRASH-2 Trial Collaborators. Effects of tranexamic acid on death, vascular occlusive events, and blood transfusion in trauma patients with significant haemorrhage (CRASH-2): a randomised, placebo-controlled trial. Lancet. 2010;376:23-32.