Anticoagulation Strategies After RFA for AF. Dabigatran vs warfarin.

1. Journal Club:
Feasibility and Safety of Dabigatran Versus Warfarin
for Periprocedural Anticoagulation in Patients Undergoing
Radiofrequency Ablation for Atrial Fibrillation
Michael G. Katz, MD
Fellow in Cardiovascular Disease
University of Rochester
May 7, 2012

2. Introduction and rationale
• Radiofrequency ablation has become standard
of care of sym,ptomatic patients in whom
antiarrythmic drugs have failed

3. • 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

4. Peri-Procedural Anticogulation Strategy
Pre-ablation Intra- Post-
(Bridging)
Maintenance Procedural procedural

5. 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)

6. 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.

7. 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

8. Dabigatran? (other novel agents?)

10. • 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

11. 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

12. 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)

13. 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

14. 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.

15. 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)

16. 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?

17. 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

18. 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

19. Pre-RFA Markedly Enlarged LA?
TEE Smoke?
Intra-Procedural
Anticoagulation
UFH loading dose (100-140 U/kg) prior to, or immediately upon,
transeptal puncture
UFH 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 echo
contrast or significant atrial enlargement
Discontinue UFH infusion once all catheters are removed from left atrium

20. Post-Procedural Recs
Warfarin Pathway
(PREFERRED – Esp with
High Bleeding Risk)
Low Bleeding Risk Pts High Bleeding Risk
Continue, unint UFH started several hours after
errupted 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