13.3 Anticoagulants and Antiplatelets: The SDCEP Protocol

3. Anticoagulant and Antiplatelet Management: SDCEP Guidelines

In the UK, management of dental patients on antithrombotic medications is strictly governed by the evidence-based guidance of the Scottish Dental Clinical Effectiveness Programme (SDCEP: Management of Dental Patients Taking Anticoagulants or Antiplatelet Drugs).

                  Patient on Antithrombotic Therapy Requiring Extraction
                                            │
       ┌────────────────────────────────────┼────────────────────────────────────┐
       ▼                                    ▼                                    ▼
   Warfarin                              DOACs                             Antiplatelets
(Vitamin K Antagonist)        (Apixaban, Rivaroxaban, Dabigatran)       (Aspirin, Clopidogrel)
       │                                    │                                    │
Check INR ≤ 72 hrs pre-op             Low Bleeding Risk:                   Single Antiplatelet:
       │                               Do NOT alter timing                  Do NOT stop
       ├── If INR < 4.0:                    │                                    │
       │   PROCEED without             Higher Bleeding Risk:               Dual Antiplatelet (DAPT):
       │   stopping Warfarin           • Once-daily: Delay AM dose          NEVER stop without
       │                               • Twice-daily: Omit AM dose          Cardiologist OK
       └── If INR ≥ 4.0:               • NO Heparin Bridging                     │
           DEFER & contact GP                       │                                    │
       └────────────────────────────────────┴────────────────────────────────────┘
                                            │
                                            ▼
                             Mandatory Local Haemostasis:
                 Oxidized Cellulose (Surgicel) + Resorbable Sutures
                 + Biting on 5% Tranexamic Acid Gauze (20 mins)

Warfarin (Vitamin K Antagonist)

Warfarin inhibits the enzyme vitamin K epoxide reductase (VKORC1), blocking the gamma-carboxylation of glutamic acid residues on vitamin K-dependent clotting factors (Factors II, VII, IX, and X) and regulatory proteins C and S. Therapy is monitored using the International Normalised Ratio (INR), which standardises Prothrombin Time (PT).

• The INR Check Timing: The patient's INR must be assessed within 72 hours prior to the procedure. If the patient has a history of an unstable INR, fluctuating diet, or concurrent antibiotic/antifungal therapy, the INR must be measured within 24 hours.
• The Safe INR Threshold ($< 4.0$): If the INR is $< 4.0$, proceed with minor oral surgery (extractions of up to 3 teeth, subgingival scaling) WITHOUT interrupting or altering the warfarin dose. Discontinuing warfarin exposes the patient to an immediate, catastrophic risk of thromboembolic stroke, deep vein thrombosis, or mechanical prosthetic valve thrombosis—a clinical risk far exceeding the morbidity of localized post-operative socket oozing.
• INR $\ge 4.0$: Defer invasive dental care. Do not adjust the warfarin dose yourself; refer the patient to their anticoagulant clinic or general practitioner for dose titration.
• Mandatory Local Haemostatic Measures:
  1. Pack the extraction socket with oxidized regenerated cellulose (Surgicel) or resorbable collagen sponge.
  2. Place interrupted resorbable sutures (e.g., 3-0 or 4-0 polyglactin 910 [Vicryl]) to approximate gingival wound edges under tension-free closure.
  3. Instruct the patient to bite firmly on a sterile gauze pack soaked in 5% tranexamic acid solution for 20 minutes.
  4. Advise the patient to avoid hot food/drinks, vigorous rinsing, or strenuous exercise for 24 hours, and prescribe paracetamol for analgesia (avoid NSAIDs and aspirin).

Direct Oral Anticoagulants (DOACs)

DOACs (also known as Non-Vitamin K Antagonist Oral Anticoagulants, NOACs) directly and selectively inhibit specific enzymes in the coagulation cascade. They exhibit rapid onset (1 to 3 hours), predictable pharmacokinetics, short elimination half-lives (10 to 14 hours in normal renal function), and do not require routine INR monitoring:

• Direct Factor Xa Inhibitors: Apixaban (Eliquis) (twice daily), Rivaroxaban (Xarelto) (once daily), and Edoxaban (Lixiana) (once daily).
• Direct Thrombin (Factor IIa) Inhibitor: Dabigatran etexilate (Pradaxa) (twice daily).

SDCEP Protocol for DOAC Management in Dental Surgery

1. Procedures with Low Risk of Bleeding (Simple extraction of 1 to 3 teeth, local scaling, restorations with subgingival margins):
   • Do NOT alter the DOAC dose or timing. Treat the patient at any time during the day and apply local haemostatic measures.
2. Procedures with Higher Risk of Bleeding (Extractions of $\ge 4$ teeth, surgical extractions with mucoperiosteal flaps, bone guttering, or gingival recontouring):
   • Once-Daily DOAC (taken in the morning, e.g., Rivaroxaban): Advise the patient to delay their morning dose on the day of surgery until after the procedure and haemostasis is confirmed, or take their normal dose in the evening.
   • Twice-Daily DOAC (e.g., Apixaban, Dabigatran): Advise the patient to omit the morning dose on the day of surgery. The normal evening dose is resumed that night, provided active bleeding has ceased.
   • Treat Early in the Day: Perform surgical procedures early in the morning so that any late secondary oozing can be addressed during working clinic hours.
   • No Heparin Bridging: Unlike warfarin in high-risk patients, DOACs never require bridging with low-molecular-weight heparin (LMWH) due to their rapid clearance and immediate therapeutic onset.

Antiplatelet Drugs (Aspirin, Clopidogrel, Ticagrelor)

• Single Antiplatelet Therapy: Patients taking Aspirin (75 mg OD) or Clopidogrel (75 mg OD) as monotherapy should NOT stop their medication prior to dental extractions. Local haemostatic measures are entirely sufficient to achieve stable haemostasis.
• Dual Antiplatelet Therapy (DAPT): Patients who have undergone coronary artery stent placement or acute coronary syndrome take Aspirin combined with Clopidogrel, Ticagrelor, or Prasugrel. DAPT must NEVER be stopped without direct consultation and approval from the patient's cardiologist. Abrupt cessation of DAPT precipitates acute coronary stent thrombosis and fatal myocardial infarction. Minor oral surgery can be safely executed on DAPT utilizing meticulous suturing, haemostatic socket packing, and pressure packs.

5. Clinical Traps, Worked Scenarios, and Practical Governance

[!CAUTION] Clinical Trap: Discontinuing Warfarin Prior to Minor Extractions: A dental practitioner instructs a patient with atrial fibrillation taking warfarin (current INR 2.8) to stop taking warfarin 3 days prior to an extraction to "prevent bleeding complications". Two days later, the patient suffers a massive ischaemic stroke secondary to left atrial thrombus embolisation. Under UK SDCEP guidelines, discontinuing warfarin with an INR $< 4.0$ for minor oral surgery is negligent clinical practice. The risk of thromboembolism far exceeds the risk of localized bleeding, which is easily controlled with sutures, Surgicel, and tranexamic acid gauze.

[!WARNING] Clinical Trap: Cannulating the Arm with an Arteriovenous Fistula: A dental team treating an anxious dialysis patient under conscious sedation cannulates the cephalic vein in the patient's left forearm, ignoring a prominent surgical scar and a palpable vascular "thrill". The cannulation causes a massive haematoma, intraluminal thrombosis, and complete failure of the patient's radiocephalic (Brescia-Cimino) arteriovenous fistula. The patient requires emergency vascular surgery and temporary central venous catheterization with high infection risk. Always examine both arms before placing a blood pressure cuff or IV cannula in renal patients.

Worked Clinical SBA Scenario

Scenario: A 62-year-old male with a history of persistent non-valvular atrial fibrillation is taking Apixaban 5 mg twice daily. He presents to your dental clinic requiring a surgical extraction of tooth 36 involving root sectioning and a buccal mucoperiosteal flap. He has normal renal function. The procedure is scheduled for 09:30 AM.

Question: According to the Scottish Dental Clinical Effectiveness Programme (SDCEP) guidance, what is the exact advice regarding the patient's Apixaban regimen on the day of surgery, and what local haemostatic measures are mandatory?

Analysis and Clinical Governance: Surgical extraction involving a mucoperiosteal flap and bone removal is classified under SDCEP as an invasive procedure with a higher risk of bleeding. Because Apixaban is a twice-daily direct Factor Xa inhibitor with a peak plasma level occurring 1 to 3 hours post-ingestion, taking the morning dose prior to an 09:30 AM appointment would coincide surgery with peak anticoagulation. Under SDCEP guidance, the patient should be instructed to omit the morning dose of Apixaban on the day of surgery. The surgical procedure is performed in the morning. The socket is packed with oxidized regenerated cellulose (Surgicel), closed with resorbable sutures, and the patient bites on 5% tranexamic acid-soaked gauze for 20 minutes. Once haemostasis is verified, the patient is instructed to resume their normal evening dose of Apixaban that night (at least 4 hours post-haemostasis). No heparin bridging is required.