Atrial Fibrillation Anticoagulation

Aka: Atrial Fibrillation Anticoagulation, Anticoagulation in Atrial Fibrillation

1. See Also
   1. Guidelines 2000 CPR and Emergency Cardiovascular Care
   2. Atrial Fibrillation
   3. Atrial Fibrillation Acute Management
   4. Atrial Fibrillation Cardioversion
   5. Atrial Fibrillation Rate Control
   6. CHADS Score
   7. Outpatient Bleeding Risk Index
   8. HAS-BLED Score
2. Indications
   1. CVA Prevention in Atrial Fibrillation
   2. CHADS Score 2 or higher
   3. Consider Outpatient Bleeding Risk Index
   4. Preparation for Atrial Fibrillation Cardioversion
      1. Atrial Fibrillation longer than 48 hours
      2. Cardioversion without Anticoagulation risks embolus
3. Protocol: Anticoagulation for Cardioversion
   1. Protocol
      1. Assumes Atrial Fibrillation >48 hours or unknown
      2. See Atrial Fibrillation Acute Management for <48 hour
   2. Delayed cardioversion
      1. Anticoagulation on Coumadin for 3 weeks
      2. Atrial Fibrillation Cardioversion
      3. Anticoagulation on Coumadin for 4 more weeks
   3. Early cardioversion
      1. Intravenous Heparin for 24 hours
      2. Transesophageal Echocardiogram excludes atrial clot
      3. Atrial Fibrillation Cardioversion
      4. Anticoagulation on Coumadin for 4 more weeks
4. Management: Alternatives to Warfarin in non-Valvular Atrial Fibrillation
   1. Indications
      1. Warfarin Drug Interactions, drug level lability, or patient refuses lab monitoring
   2. Disadvantages
      1. No proven reversal agent in case of bleeding
         1. See Anticoagulant Reversal
   3. Preparations
      1. Direct Thrombin Inhibitors (e.g. Dabigatran)
         1. Fewer drug interactions Than Rivoroxaban
      2. Factor Xa Inhibitors (e.g. Rivoroxaban)
5. Management: Coumadin (Warfarin)
   1. Indications: High Risk
      1. Prior Cerebrovascular Accident or Thromboembolism
      2. Rheumatic mitral valve disease or Mitral Stenosis
      3. Prosthetic Heart Valve
   2. Indications: Moderate Risk (could consider Aspirin)
      1. Hypertension
      2. Left Ventricular Failure
      3. Cardiomyopathy
      4. Age over 75 years old
      5. Diabetes Mellitus
   3. Indications: Less Validated Factors
      1. Coronary Artery Disease with preserved LV function
      2. Age 65 to 75 years old (especially women)
      3. Hyperthyroidism
   4. Adverse Effects
      1. Risk of hemorrhagic complications are substantial
      2. Avoid in over age 80 (risk of Hemorrhagic CVA outweighs benefit)
      3. Consider Aspirin as alternative in lower risk patients and in advanced age
   5. Efficacy: Reduces Atrial Fib CVA risk
      1. Untreated: 3.6 to 7.4% risk of CVA/year
      2. Aspirin (325 qd): 2.5 to 3.6% risk of CVA/year
      3. Coumadin 0.9 to 3.5% risk of CVA/year
         1. Benefits outweigh bleeding risk if high risk
   6. Dosing
      1. Target INR 2-3
      2. Tight INR control is important
         1. INR 1.5-1.9 with 2 fold risk of severe CVA
         2. INR 1.5-1.9 with 3 fold risk of mortality
         3. Hylek (2003) N Engl J Med 349:1019-26
   7. References
      1. Van Walraven (2002) JAMA 288:2441-8
6. Management: Aspirin
   1. Indications
      1. Low risk (Lone Atrial Fibrillation)
         1. Under age 60 years without Coronary Artery Disease
         2. Low risk of Thromboembolism (<.5% risk)
         3. Age >75 years without other Thromboembolism risk
      2. Risk of bleeding on Coumadin outweighs benefits
         1. See HAS-BLED Score
         2. See Outpatient Bleeding Risk Index
         3. Age >65 years
         4. History of Gastrointestinal Bleeding
         5. History of Cerebrovascular Accident
         6. Recent Myocardial Infarction
         7. Hematocrit <30%
         8. Creatinine >1.5
         9. Diabetes Mellitus
      3. References
         1. Man-Son-Hing (2002) Arch Intern Med 162:541-50
   2. Dosing
      1. Aspirin 325 qd
7. References
   1. (2000) Circulation, 102(Suppl I):86-9
      1. http://www.circulationaha.org
   2. Albers (2001) Chest 119(1 suppl):S194-206