Single Extraction in a Patient With a Mechanical Mitral Valve and an INR of 3.4
A 67-year-old man requires extraction of the mandibular right first molar (46). The tooth is non-restorable because of subgingival caries extending below the distal bone crest; it has a 5 mm periapical radiolucency and a buccal swelling that has been present for a week. He is afebrile (37.2 °C), has no dysphagia or trismus, and feels well. His history includes a mechanical mitral valve replacement in 2019 (bileaflet prosthesis), atrial fibrillation and hypertension. His medicines are warfarin (target INR 2.5 to 3.5), amiodarone, bisoprolol and ramipril; he occasionally takes ibuprofen for back pain. His INR was measured two days ago at 3.4. He has read online that warfarin must be stopped three days before any dental surgery, and a friend who is a pharmacist has already suggested stopping it and switching to enoxaparin injections. He asks you to prescribe strong antibiotics and a painkiller and to take the tooth out today.
1. How do you manage his anticoagulation? State what INR is acceptable, what you do about bridging, and whom you contact.
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Do not stop the warfarin and do not bridge with enoxaparin.
- The indication is a mechanical mitral valve. Interrupting anticoagulation exposes him to valve thrombosis and embolic stroke - a far greater and less reversible risk than bleeding from one socket.
- Bridging with low-molecular-weight heparin adds bleeding risk without proven benefit for dental procedures and is not recommended for a simple extraction.
- For a single simple extraction, current guidance (for example SDCEP) allows the procedure to go ahead with an INR checked within 24–72 hours provided it is 4.0 or below. His INR of 3.4 is therapeutic for his valve and acceptable. Most such referrals are unnecessary.
- Ideally the extraction is done on the same day as a recent INR. If the reading is older than 72 hours, arrange a repeat. Note that amiodarone inhibits warfarin metabolism and can push the INR up, so a recent level matters more than usual here.
- Contact his anticoagulation clinic or physician, confirm the target range and the latest reading, state the planned procedure date, and document the conversation. Agree who he should contact if bleeding occurs.
If the INR were above 4.0, unstable, or if several teeth or surgical bone removal were needed, the procedure would be deferred and the anticoagulation clinic consulted. For this single extraction with local measures, that is not required.
2. Describe your local haemostatic plan and justify your choice of analgesic and of antibiotic, if any.
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Local haemostasis is what makes this safe
- Atraumatic extraction, avoiding a buccal flap if possible; gentle curettage and socket compression.
- A haemostatic agent in the socket (oxidized cellulose or collagen sponge), a figure-of-eight resorbable suture, and pressure with a gauze pack for 10–20 minutes.
- Tranexamic acid 4.8% mouthwash, 10 mL four times daily for two days, starting on the day of extraction.
- Written instructions: no vigorous rinsing, no sucking, no hot drinks or alcohol for 24 hours, and an emergency contact number.
Analgesia. Paracetamol 1 g four times daily. Avoid ibuprofen and other NSAIDs: they impair platelet function and add gastrointestinal risk in a warfarin patient. Advise him to stop the occasional ibuprofen and record the advice. If paracetamol is inadequate, speak to the anticoagulation clinic before adding anything.
Antibiotic. Not indicated routinely. This is a chronic periapical infection with localised swelling but no systemic involvement - no fever, no trismus, no dysphagia. The extraction achieves drainage, which is the treatment. If systemic features appeared, phenoxymethylpenicillin or amoxicillin would be an appropriate adjunct. Avoid metronidazole, which markedly potentiates warfarin, unless it is essential and the INR can be monitored with dose adjustment. Any new medicine warrants an INR check within a few days, and this must be planned rather than assumed.
3. What findings would make you defer treatment and refer him to an oral and maxillofacial unit or hospital instead?
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Defer and refer if:
- The INR is above 4.0, unstable, or more than 72 hours old and cannot be repeated.
- The extraction requires surgery - bone removal, sectioning, a flap, a deeply impacted tooth - or several teeth at once. These need a hospital or oral surgery setting with haematology support and access to prothrombin complex concentrate or fresh frozen plasma.
- There are signs of spreading infection: trismus, dysphagia, floor-of-mouth swelling, fever, malaise, facial cellulitis. That means drainage, possibly admission, not an outpatient extraction.
- His medical status has changed: recent valve surgery, decompensated heart failure, uncontrolled hypertension, new thrombocytopenia, or a new anticoagulant added.
- He has had recent bleeding episodes or a fall, which alters the risk balance.
Also verify the antibiotic prophylaxis policy for a mechanical heart valve before the appointment, since guidance differs between countries; document the decision either way. The judgement being tested is recognising that the dominant risk in this patient is thromboembolism, not haemorrhage, and that the online advice he found is wrong for a single dental extraction with local measures.