Dabigatran for Atrial Fibrillation: Cardioversion and Ablation

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The presentation covers background information regarding atrial fibrillation (A-fib) and the use of oral anticoagulant dabigatran surrounding cardioversion and ablation for A-fib. The information surrounds a patient case in which the patient prefers dabigatran over warfarin. Available literature on the topic is analyzed to make a patient specific recommendation.

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  • 1.Dabigatran for Atrial Fibrillation: Cardioversion and Ablation July 18, 2013 Marti Larriva, PharmD Candidate

2. Outline Patient Case Background Literature Summary Patient Case 3. Patient Case Mr. W 64 y/o male admitted with a chief complaint of chest pain, heart palpitations, and DOE x 1 week o EKG shows A. fib with RVRVitals Temperature98.06Pulse100Respiration18Blood Pressure120/82 PMH: HTN, sleep apnea, paroxysmal A. fib., and obesity Medications: o ASA 325 mg o Lisinopril 40 mg daily o Sotalol 160mg PO BID (HELD) CHADS2 = 1 CrCl = 90mL/min Cardiology consult o Diltiazem and heparin drip started o Plan for TEE and cardioversion o Patient does not want warfarin, was offered dabigatran and wants it instead. 4. Clinical Question What is the role of dabigatran as an anticoagulant during cardioversion or ablation for atrial fibrillation? 5. Background Atrial Fibrillation Cardioversion/Ablation Dabigatran 6. Atrial Fibrillation 7. Atrial Fibrillation PathophysiologyPulmonary vein reentry circuitsReversible CausesCardiac surgery, pericarditis, myocardial infarction, hyperthyroidism, pulmonary embolism, pulmonary disease, and excessive alcohol ingestionSymptomsCommon - palpitations, tachycardia, weakness, dizziness, lightheadedness, reduced exercise capacity, mild dyspnea Severe - dyspnea at rest, angina, presyncope, syncope, embolic event, right sided heart failureClassificationParoxysmal 2 episodes that terminates spontaneously in 7 days or lessPersistent AF that does NOT terminate after 7 daysPermanent AF for which cardioversion has failed or not been attempted Cheng A, Kumar K. Overview of atrial fibrillation. In: UpToDate, Baslo, DS (Ed), Waltham, MS, 2013 8. Atrial FibrillationTreatment General o o o o oTreat any underlying reversible causes Slow ventricular rate beta blockers, non-DHP calcium channel blockers Convert to normal sinus rhythm direct current, pharmacologic Prevent recurrences ablation Prevent stroke/improve survival anticoagulationCongestive Heart Failure, Hypertension, Age > 75, Diabetes, Stroke CHADS2 ScoreEvents per 100 patient years OR % per year00.4911.5222.5035.2746.025 or 66.88Go AS, Hylek EM, Chang Y, et al. JAMA. 2003;290(20):2685-2692 Cheng A, Kumar K. Overview of atrial fibrillation. In: UpToDate, Baslo, DS (Ed), Waltham, MS, 2013 9. Cardioversion Direct current or antiarrhythmic to return to NSR Reasons to CardiovertReasons NOT to CardiovertUnstable hemodynamics or worsening symptoms due to AFMinimally symptomaticFirst episode, irrespective of long term control strategyMultiple comorbidities OR Overall poor prognosis Stroke risk post-cardioversion is 1-5% over 1 month o Higher than baseline risk of 1-6% over 1 year Duration of AFPre-CardioversionPost-Cardioversion 48 hLMWH/UFH at therapeutic doses on presentationOral Anticoagulation x 4 weeks Stop/Continue based on rhythm> 48hTEE and/or Oral Anticoagulation x 3 weeksOral Anticoagulation x 4 weeks Stop/Continue based on rhythmYou JJ, Singer DE, Howard PA et al. Chest.2012;141(2 Suppl):e531S-75S. Naccarelli G, Ganz L, Manning W. Restoration of sinus rhythm in atrial fibrillation. In: UpToDate, Baslo, DS (Ed), Waltham, MS, 2013 10. Ablation Radiofrequency catheter ablation is applied to pulmonary veins suspected of initiating AF. o Success ranges from 50-80% Complications: o Periprocedural Embolism (CVA/TIA) 0.5 - 2.0% o Cardiac tamponade > 1% Most frequent cause of death o Pulmonary vein stenosis 1.0 - 3.0% No clear anticoagulation strategy o Continuous warfarin therapy shown to be safe and effective o Unclear safety and efficacy of dabigatran Passman, R. Radiofrequency ablation to prevent recurrent atrial fibrillation. In: UpToDate, Baslo, DS (Ed), Waltham, MS, 2013. 11. Dabigatran MechanismDirect thrombin inhibitorPharmacokineticsTime to peak 1 hour Excreted 80% in urine Metabolized to active form by plasma/hepatic esterasesDosage forms75mg, 150mgRenal dose adjustment > 50 mL/min: no dose adjustment 30-50 mL/min adjust dose in concomitant interacting medication that increases dabigatran concentrations 15-30 mL/min: 75 mg PO BID < 15mL/min: avoid useFDA-approved usesNonvalvular atrial fibrillationNon FDA-approved usesPostoperative thomboprophylaxis (knee/hip replacement)ContraindicationsMechanical prosthetic heart valves Active bleeding *Severe renal impairment (CrCl