Journal club 05072012 warfarin vs dabigatran for af rfa
Journal Club: Feasibility and Safety of Dabigatran Versus Warfarinfor Periprocedural Anticoagulation in Patients Undergoing Radiofrequency Ablation for Atrial Fibrillation Michael G. Katz, MD Fellow in Cardiovascular Disease University of Rochester May 7, 2012
Introduction and rationale• Radiofrequency ablation has become standard of care of sym,ptomatic patients in whom antiarrythmic drugs have failed
• Thomboembolic complications are likely related to: – Exacerbation of prothrombotic state by catheters in the LA – Endothelial denudation – Char formation – Tissue inflamation in the LA• Risk theoretically reduced by periprocedural anticoagulation. Bleeding Thromboembolism
Pre-ablation Intra- Post- (Bridging) Maintenance Procedural procedural• Reported rates of thromboembolic complications are 0.5-2.8%; higher with CHADS2 ≥ 2• Current guidelines rec 3 wks of theraputic INR on warfarin prior to electrical or chemical CV• Warfarin may be stopped 2-5 days prior to procedure• Or… warfarin may be continued without interruption (demonstrated not to increase bleeding risk in lower risk pts)• If bridging attempted: enoxaparin 1 mg/kg q12h, stopped 24 hours prior to procedure (per ACCP guidelines)
Pre-ablation Intra- Post- (Bridging) Maintenance Procedural procedural• UFH bolus(100 units/kg)followed by continuous infusion• Trial of 3 different ACT targets (250-300s, 300- 350s, 350- 400s) found lower incidence of TE at 2 highest ranges• Guidelines rec at least 300-350s; echo contrast or marked LA enlargement may warrant 350s to 400s.
Pre-ablation Intra- Post- (Bridging) Maintenance Procedural procedural• High risk of bleeding: UFH night of procedure followed by transition to LMWH as bridge to warfarin• Otherwise, LMWH as bridge to warfarin• (various regimens of LMWH have been trialed)• Long term: warfarin at least 2-3 months post ablation
• Multicenter, prospective observational registry• 8 high volume centers, Jan 2010 to July 2011• 290 pts• 145 on dabigatran – All were Rx 150 mg PO BID x 30 days• 145 on warfarin – Age, sex, AF type (parox vs chronic) matched – Tx INR (INR 2-3) for 30 days; excluded if not
Peri-Procedure anticoagulation• If taking dabigatran – Instructed to hold dose on morning of procedure – Resumed 3 hours after hemostasis• If taking warfarin – Underwent RFA on uninterrrupted warfarin therapy, including evening of the procedure
Ablation Procedure• TEE on all dabigatran patients to r/o LAA thrombus• No TEE on theraputic warfarin patients• UFH 10,000 units given prior to transseptal puncture• Goal ACT 300-400s• Pulmonary vein antral isolation using double transeptal approach (details available in paper)
Data Collection• Events within the first 30 days were included• Saftey endpoints – Bleeding: hematomas and pericardial effusion • Requirement of transfusion or intervention = Major – TE: CVA and TIA• Primary outcome was composite of bleeing and TE
Baseline characteristics• Essentially similar between subjects and procedure variables. – mean age of the study population was 60 years – 79% being male – 57% having paroxysmal AF. – no differences in the individual components of the CHADS 2 score, mean CHA DS -VASc score, HAS-BLED score, left 2 2 atrial size, left ventricular ejection fraction, and the presenting rhythm – no differences in theprocedure time, radiofrequency ablation time , or fluoroscopy time between both groups – Acute procedural success and successful PVAI did not differ between both groups.
Complications• 32 pts had complications• 29 (10%) had bleeding complications – All major bleeds were effusions req drainage (9 vs 1)• 3 (1%) had TE (all in nonparox, dabigatran group)
Discussion…• Comments regarding studied anticoagulation strategy?• What do we do locally?• Is there an on-going role for dabigatran in AF when ablation is planned?
Proposed algorithm based on this study and current guidelines CHADS2 TE RF CHA2DS2-VASc Patient stratification with AF HAS-BLED Bleeding RF HEMORR2HAGES stratification Dabigatran ASA 325 mg Warfarin 150 mg BID Antiarrythmic tx failing anticipate RFA Consider warning dabigatran pt’s about Early Pre-RFA, TE elevated bleeding risk in and Bleeding re- peri-procedural setting assessment AND switching to warfarin
Pre-AF RFA Anticoagulation Strategy Thromboembolic Risk Low High Stop Antiplatelet agents Stop Antiplatelet agents On warfarin: On warfarin: + no bridging + no bridging On dabigatran: Bleeding Risk Low On dabigatran: + stop 72 hours prior to RFA + stop 72 hours prior to RFA + enoxaparin 1 mg/kg 48hr + enoxaparin 0.5 or 1 mg/kg prior to RFA, last dose on AM on AM of RFA of RFA Stop Antiplatelet agents On warfarin: + Stop 2-5 days prior to RFA High On dabigatran: + stop 72 hours prior to RFA Admit day prior to RFA + Initiation of UFH with PTT foal of 50-75
Pre-RFA Markedly Enlarged LA? TEE Smoke? Intra-Procedural AnticoagulationUFH loading dose (100-140 U/kg) prior to, or immediately upon,transeptal punctureUFH continuous infusion (10-18 U/kg/hr) titrated to target ACT• Maintain ACT target of at least 300-350 seconds• Consider higher ACT target of 350-400 seconds if spontaneous echocontrast or significant atrial enlargementDiscontinue UFH infusion once all catheters are removed from left atrium
Post-Procedural Recs Warfarin Pathway (PREFERRED – Esp with High Bleeding Risk) Low Bleeding Risk Pts High Bleeding RiskContinue, unint UFH started several hours aftererrupted after Enoxaparin 1 mg/kg q12h beginning the sheath pulled. Next AM, stop UFH RFA evening of procedure as bridge to Tx INR and start enoxaparin 0.5 to 1 mg / kg as bridge to tx INR If also low TE risk Consider using enoxaparin 1 mg/kg for the first 1 or 2 doses and then decreasing to 0.5 mg/kg twice daily until tx INR achieved Treat all Pt’s as High Bleeding Risk Dabigatran Pathway (Discouraged) UFH started several hours after sheath pulled. Next AM give first dose of dabigatran and stop UFH 2 hours later