A recording of this presentation is available HERE.
***
Thanks to Dr. Bao Chau Nguyen for a great review of Anticoagulation this week, with a quick review of warfarin, heparin/LMWH, and a particular focus on the Direct Oral Anticoagulants (DOACs), which have become the mainstay of anticoagulation.
Dr. Nguyen reminded us of the current 2025 indications for Vitamin K antagonist (warfarin), which have dwindled to three at this point
- mechanical heart valves
- atrial fibrillation with mod/severe mitral stenosis (esp rheumatic disease)
- antiphospholipid syndrome (APLS)
She also reminded us of the many challenges with Vit K antagonists, which include frequent monitoring, drug-food interactions, and drug-drug interactions.
Current indications for DOACs as first line:
- non-valvular Afib
- treatment of VTE (DVT/PE)
- prevention of VTE (extended)
- select stable PAD/CAD
Summary of indication and dosing of available DOACs:
Dabigatran
- AF: 150 mg BID, reduce to 110 mg BID (age >80, high bleed risk, interacting drugs), Avoid if CrCl <30 (varies by region)
- VTE: 5 days parenteral therapy, then 150 mg BID, 110 mg BID if elderly or high bleeding risk
Apixaban
- AF (stroke prevention): 5 mg BID, Reduce to 2.5 mg BID if ≥2 of the following: Age ≥ 80, Weight ≤ 60 kg, Creatinine ≥ 1.5 mg/dL (or CrCl <30–50 depending on guideline nuance)
- VTE: 10 mg BID x7 days, then 5 mg BID
- Extended therapy (>6-12 months): 2.5 mg BID
- AF: 20 mg once daily with food, reduce to 15 mg daily if CrCl 15–49 ml/min
- VTE: 15 mg BID x21 days, then 20 mg daily with food
- AF: 60 mg daily, reduce to 30 mg daily if CrCl 15–50, Weight ≤ 60 kg, certain P-gp inhibitors
- VTE: 5 days of initial parenteral anticoagulation, then 60 mg daily (or 30 mg if meeting criteria above)
Reversal agents for DOACs:
Factor Xa inhibitors (Apixaban, Rivaroxaban, Edoxaban): Andexanet alfa (preferred when available), 4-factor PCC 50 units/kg if andexanet unavailable
Dabigatran: Idarucizumab 5 g IVAdjuncts: tranexamic acid, local control, supportive care.
There are now practice guidelines for pausing and restarting DOAC in setting of non-urgent surgery
Finally, Dr. Nguyen presented three important 2025 updates on DOACs:
1) DOAC vs. warfarin in CKD patients (SCr<25), a metanalysis of >71K patients with Atrial fibrillation and CKD, which found that standard dose of DOAC compared to warfarin showed decrease risk of CVA, systemic embolism and ICH, with similar risk of bleeding. HOWEVER, inappropriate dose reduction of DOAC resulted in increased risk of CVA and death. Take home: DOACs are safe and effective in patients with AFib and decreased GFR but should be regular/full dose.
https://www.jabfm.org/content/early/2025/01/16/jabfm.2024.240155R0?utm_source=chatgpt.com
2) DOAC for patients with BMI >50: retrospective cohort study of 754 patients that compared DOAC to warfarin and found a non-statistically significant trend toward favoring DOAC (outcomes CVA, all cause mortality, major bleeding). Take home: DOACs are probably better than warfarin for morbidly obese patients with BMI>50.
https://www.sciencedirect.com/science/article/pii/S240584402417627X?utm_source=chatgpt.com
3) Reduced dosage of DOAC in extended treatment of VTE: systematic review and metanalysis of 5 RCTs looking at recurrent VTE, major bleeding. Found no significant increase in recurrent VTE between reduced vs. full dose, significantly lower bleeding risk in reduced dose group. Take home: It appears safe and effective to reduce DOAC to half dose after treating for acute VTE (usually 6 months).
No comments:
Post a Comment