Can Catheter Ablation of AF Reduce the Risk of Stroke? CCCEP 2015 October 31, 2015

Transcription

1 Can Catheter Ablation of AF Reduce the Risk of Stroke? CCCEP 2015 October 31, 2015 Atul Verma, MD FRCPC FHRS Director, Heart Rhythm Program Southlake Regional Health Centre Newmarket, Ontario, Canada Chair, Heart Rhythm Working Group, Cardiovascular Care Network Assistant Professor, University of Toronto Adjunct Professor, McGill University

2 Disclosures Moderate Support (honoraria, speaking bureau, research) St Jude Medical International Medtronic Canada Biosense Webster Sanofi Aventis Boehringer Ingelheim Advisory Board St Jude Medical International Biosense Webster Sanofi Aventis Boehringer Ingelheim

3 Background AF is associated with increased risk of stroke Risk of stroke is related to clinical factors CHADS 2 CHA 2 DS 2 -VASc But AF burden may be related to risk of stroke as well

4 AF Burden is Related to Stroke Risk NEJM 2012

5 ASSERT Monitored pacemaker patients for 3 months Looked for at least 6 minutes of subclinical atrial tachyarrhythmias on pacemaker Followed patients for 2.5 years afterwards Median number of episodes was 2

6 ASSERT

7 ASSERT Hazard ratios by duration of episodes: Q1 (<0.86 hours) 1.23 Q2 ( hrs) 0.00 Q3 ( hrs) 1.18 Q4 (>17.72 hrs) 4.89

8 TRENDS Circ EP 2009

9 Botto study JCE 2009

10 Background Catheter ablation increasingly used in treatment of AF Short and long-term results promising, but often require more than one procedure

11 Ganesan AN et al, J Am Heart Assoc 2013;2:e004549

12 Background Small, cohort studies showing that risk of stroke is decreased in patients post-ablation

13 Centres N Follow -up (mo) CHADS 2 score OAC stopped Oral Single US Not stated 78% of CHADS 0 Events per year in OAC stopped and 68% 1 Nademanee Single US Not stated; mean about 1 84% 0.4% per year Themistoclakis 5 US/ %=0, 27%=1, 13%=2 80.2% 0.04% strokes per year Europe Chao Single Taiwan Saad Single Brazil Yagishita Single Japan Hunter UK/ Australia Median 1 Not clear 1.5% stroke/tia per year for whole group (i.e. on and off OAC) Mean % =85%, 2 or more=15% 82% 0.16% per year (in those stopping OAC) 57%=0, 34%=1, 7%>1 64% 0.16% stroke/tia Per year Guiot Single US Mean % 1% stroke per year Reynolds US multicenter % 3.4 % stroke/tia per year for whole group Bunch Single US %=0, 20%=1, 5%=2, 56%>2 Gaita Single %=0 or 1, 16%=2+, Italy 5%=3+ Not included 65% (OAC continued if CHADS 2 2) 0 (i.e. on and off OAC) 1.5% risk of stroke per year in ablation arm 0.2 per 100 patientyears for those off OAC

14 Reynolds et al, Circ Cardiovasc Qual Outcomes 2012;5(2):171-81

15 Background Can reduction of AF burden by ablation significantly reduce the risk of stroke? CABANA (n=2200) - Mayo Primary endpoint = total mortality, disabling stroke, serious bleeding, or cardiac arrest Stroke will be a secondary endpoint EAST (n=2745) German AF NET Composite of cardiovascular death, stroke and hospitalization due to worsening of heart failure or due to acute coronary syndrome Stroke will be a secondary endpoint

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18 WHAT ARE PHYSICIANS DOING PRESENTLY?

19 Survey done Nov 2009

20 36/37 EP physicians doing AF ablation completed study

21 Survey done Spring 2012

22 Atul Verma, MD FRCPC Southlake Regional Health Centre David Birnie, MD FRCPC University of Ottawa Heart Institute

23 Hypothesis We hypothesize that the strategy of OAC will be superior to antiplatelet therapy alone for reducing risk of stroke, systemic embolism, or silent cerebral infarction post-successful ablation of AF.

24 Primary Outcome Composite of stroke, systemic embolism, and silent cerebral infarction as defined as occurrence of one or more new lesions >/= 15 mm detected between a baseline and final (3 year) MRI scan

25 Inclusion Criteria 1. At least one year post-successful catheter ablation for AF or left atrial arrhythmia. Successful AF ablation is defined as no AF/AFL/AT >30 seconds on any preenrolment monitoring. 2. Patient must have a CHADS2 risk score of 1 or more. Patients with CHADS2 score of 0, but who are >65 years old, or who are female with vascular disease will also be included (as per the Canadian Cardiovascular Society AF guidelines update) and will be included in the CHADS2 score 1 randomization stratum. 3. Patient must be >18 years of age.

26 Pre-enrollment screening for AF

27 Study Schematic Within 2 months of enrolment Enrolment Screening Patients 12 months or more postsuccessful AF ablation Preenrolment Holter 48 hour Holter to rule out any AF/AFL/AT >30 sec Baseline cerebral MRI scan (all patients) Implant of long-term, continuous AF monitor (subset of patients) Randomization ASA Rivaroxaban 6, 12, 24, 36 months History, physical exam, ECG, 24 hour Holter, collection of continuous monitor data (in subset who have one) 12 month & 36 month repeat cerebral MRI scan (all patients)

28 Sample Size Annual event rate 3.5% Crossover 7.5% in ASA arm, 1.5% in rivaroxaban arm 2% loss to follow-up 80% power, 0.05 two-sided alpha N=1452 (726 per arm)

29 Conclusions We need to know if reduction of AF burden postcatheter ablation can have any impact on stroke Early evidence suggests it does CABANA and EAST will provide some answers OCEAN will hopefully provide more specific data