Transcript AFib Management and the Role of Catheter Ablation
AFib Management and the Role of Catheter Ablation
Slide Kit Structure
Section I. AFib Overview Section II. Clinical Management of AFib Section III. Catheter Ablation for the Treatment of AFib
Section I:
AFib Overview
Atrial fibrillation
• Atrial fibrillation (AFib) is a common disease that causes the upper chambers of the heart (atria) to beat rapidly and in an uncontrolled manner (fibrillation). • Uncoordinated, rapid beating of the atria affects the flow of blood through the heart, causing an irregular pulse and sometimes a sensation of fluttering in the chest.
Classification of AFib Subtypes
Paroxysmal Persistent Permanent Spontaneous termination usually < 7 days and most often < 48 hours Does not interrupt spontaneously and needs therapeutic intervention for termination (either pharmacological or electrical cardioversion) AFib in which cardioversion is attempted but unsuccessful, or successful but immediately relapses, or a form of AFib for which a decision was taken not to attempt cardioversion Levy S, et al. Europace (2003) 5: 119
Prevalence of AFib General population-based prevalence
0.95%
ATRIA study
2.5%
Olmsted County study
Go AS, et al.
JAMA
(2001) 285: 2370 Miyasaka Y, et al.
Circulation
(2006) 114: 119
Prevalence of AFib in the General Population in USA and EU
ATRIA
USA 2.8 million
( 300 million inhabitants)
Olmsted
7.4 million EU 4.3 million 11.4 million
( 456 million inhabitants of 25 member states)
Prevalence of AFib
Olmsted County study
15.9
16
15.2
14.3
14 12 10 8 6
5.1
4
5.1
2
5.9
5.6
6.7
6.1
7.7
6.8
8.9
7.5
10.2
8.4
11.7
9.4
13.1
10.3
11.1
11.7
12.1
0 2000 2005 2010 2015 2020 2025
Year
2030 2035 2040 2045 2050 Miyasaka Y, et al. Circulation (2006) 114: 119
Incidence of AFib in the General Population – Gender Differences
Olmsted County study
Observational period: 20 years
Men Women 0.49 % 0.28 % Ratio men to women = 1.86
Miyasaka Y, et al.
Circulation
(2006) 114: 119
Principal Reasons for Increasing Incidence and Prevalence of AFib
1.
The population is aging rapidly, increasing the pool of people most at risk of developing AFib 2.
Survival from underlying conditions closely associated with AFib, such as hypertension, coronary heart disease and heart failure, is also increasing 3.
According to the Olmsted County study, the increase is also related to the increasing population 4.
These figures may also be significantly under estimated because they do not take into account asymptomatic AFib (25% of cases in Olmsted survey) Miyasaka Y, et al.
Circulation
(2006) 114: 119 Steinberg JS, et al.
Heart
(2004) 90: 239
AFib has an Impact on All Aspects of QoL
SF-36 quality of life scores in AFib patients and healthy subjects
SF-36 scale
General health Physical functioning Role physical Vitality Mental health Role emotional Social functioning Bodily pain
AFib patients (n=152)
54
±
21 68
±
27 47
±
42 47
±
21 68
±
18 65
±
41 71
±
28 69
±
19
Healthy controls (n=47)
78
±
17* 88
±
19* 89
±
28* 71
±
14* 81
±
11* 92
±
25* 92
±
14* 77
±
15*
* p<0.001
Dorian P, et al.
J Am Coll Cardiol
(2000) 36: 1303
Risk Factors for AFib
ATRIA study
Characteristic
Diagnosed heart failure
Hypertension
Diabetes mellitus Previous coronary heart disease
Baseline characteristics of 17,974 adults with diagnosed AFib, July 1, 1996-December 31, 1997 (n=17,974)
29.2%
49.3%
17.1% 34.6%
Go AS, et al.
JAMA
(2001) 285: 2370
AFib is Responsible for 15-20% of all Strokes
– AFib is responsible for a 5-fold increase in the risk of ischaemic stroke 12 8 4 Women AFib+ Women AFib Men AFib+ Men AFib 0 1 2 3 4 5
Years of follow-up
1 2 3 4 5 Wolf PA, et al. Stroke (1991) 22: 983 Go AS, et al. JAMA (2001) 285: 2370 Friberg J, et al.
Am J Cardiol
(2004) 94: 889
Increased Risk of Cardiovascular Events
Death or hospitalization in individuals with CV event(s) after 20 years
100 Men
89
Women 80
66
60
45
40
27
20 0 AFib No AFib AFib No AFib Stewart S, et al.
Am J Med
(2002) 113: 359
Mortality Associated with AFib
Framingham Heart Study, n=5209
80 60 Men AFib+ Women AFib+ 40 20 Men AFib Women AFib 0 0 1 2 3 4 5 6 Follow-up (y) 7 8 9 10 Benjamin EJ, et al.
Circulation
(1998) 98: 946
Incremental AFib Healthcare Costs
UK costs for AFib in 1995 vs. 2000
• 1995: Direct cost of AFib in the UK between £244 and £531 million (0.6–1.2% of overall health care expenditure) • 2000: £459 million direct cost – double that in 1995 (0.9–2.4% of NHS expenditure) Cost of heart failure admission Cost of stroke admission warfarin use 10% admission 10% community based care
Base cost of AF in 2000
0 Base cost of AFib +5.1% +7.4% +5.6% +50% +48% 100 200 300 400 500 600 Total health care expenditure (£ million) Base cost of associated conditions and procedures 700 Incremental cost of AFib Other costs Stewart S, et al.
Heart
(2004) 90: 286
Major Costs in Treatment of AFib
COCAF Study 9% 8% 2% 6% 52%
Hospitalizations Drugs Consultations Further investigations Paramedical procedures Loss of work
23%
Le Heuzey JY, et al.
Am Heart J
(2004) 147:121
Cost of AFib (Europe)
FIRE study
• 4507 consecutive patients with AFib/flutter admitted to ER enrolled in FIRE study (
1.5% of all ER admissions
) • 61.9% of AFib/flutter patients were hospitalized (
3.3% of all hospitalizations
) • Mean hospital stay 7+6 days Santini M, et al.
Ital Heart J
(2004) 5: 205
The Burden of AFib
• AFib is responsible for significant economic and healthcare costs – Hospitalization costs – Drug treatment – Treatment of AFib-associated co-morbidities and complications • The health and economic impact will increase with the increasing prevalence and incidence of AFib • AFib, owing to its epidemiology, morbidity, and mortality, represents a significant health problem with important social and economic implications that needs greater attention and allocation of more resources
Section II:
Clinical Management of AFib
Primary Therapeutic Aims in AFib
• Restore and maintain sinus rhythm whenever possible • Prevent thromboembolic events In order to: – Reduce symptoms and improve QoL – Minimize impact of AFib on cardiac performance – Reduce risk of stroke – Minimize cardiac remodelling ACC/AHA/ESC 2006 Guidelines for the Management of Patients With Atrial Fibrillation
J Am Coll Cardiol
(2006) 48: 854
Treatment Options for AFib
•
Cardioversion
Pharmacological • Electrical
Drugs to prevent AFib
• Antiarrhythmic drugs • Non-antiarrhythmic drugs
Drugs to control ventricular rate Drugs to reduce thromboembolic risk Non-pharmacological options
• Electrical devices (implantable pacemaker and defibrillator) • AV node ablation and pacemaker implantation (ablate & pace) • Catheter ablation • Surgery (Maze, mini-Maze)
Recurrence Following Cardioversion: AFFIRM Study
AFFIRM: most recurrences occur within 2 months of cardioversion 100
Treatment Arm
Rate control Rhythm control 80 60 40 20 Log rank statistic = 58.62
p<0.0001
0 0 1 N, Events (%) Rate control: Rhythm control: 563, 3 (0) 729, 2 (0) 2 3 Time (years) 4 5 167, 383 (69) 96, 440 (80) 42, 472 (87) 10, 481 (92) 344, 356 (50) 250, 422 (60) 143, 470 (69) 73, 494 (75) 6 2, 484 (95) 18, 503 (79) Raitt MN, et al.
Am Heart J
(2006) 151: 390
Amiodarone to Prevent Recurrence of AFib CTAF Study: mean follow-up 16 months
100 p<0.001
80 60 40 20 0 0 Sotalol Propafenone Amiodarone 100 200 300 Follow-up (days) 400 500 600 Roy D, et al.
N Engl J Med
(2000) 342: 913
Effectiveness of Current AADs
• Even with the most effective AAD, such as amiodarone, long-term efficacy is low
~50% or less at 1 year
Non-Pharmacological Treatment Options for AFib
• Pacemakers not curative and must be worn for life • Surgical procedures may be effective but are not a practical solution for the millions of sufferers of AFib • Catheter ablation is potentially curative
Devices Electrophysiological Surgery Pacemaker
(single or dual chamber)
Internal atrial defibrillators Catheter ablation AV node ablation Maze procedure Modified Maze (mini-Maze)
ACC/AHA/ESC 2006 Guidelines for the Management of Patients With Atrial Fibrillation
J Am Coll Cardiol
(2006) 48: 854
Management of AFib - Summary
• Current antiarrhythmic drug therapies are not highly effective in maintaining sinus rhythm and generally have poor outcomes – high recurrence rates – adverse effects and high discontinuation rate • A potentially curative therapy for AFib is desirable
Section III:
Catheter Ablation for the Treatment of AFib
Catheter Ablation
• Uses a series of long, thin wires (catheters) that are inserted through an artery or a vein and then guided through to the heart. • One of the catheters is then used to localise the source of the abnormal electrical signals and another then delivers high energy waves that neutralise (ablate) abnormal areas.
• Using catheters to reach the heart is a common approach to treat a range of heart conditions and is much less invasive than surgical treatments.
Landmarks in Catheter Ablation Techniques
Technique
Maze reproduction Right atrial linear lesions Right and left atrial linear lesions PV foci ablation Ostial PV isolation Circumferential PV ablation Ablation of non-PV foci Antral PV ablation Double Lasso technique CFAE sites ablation Ostial or circumferential or antral PV ablation plus extra lines (mitral isthmus, posterior wall, roof) Circumferential PV ablation with vagal denervation
Publication date Schwarz 1994 Haïssaguerre 1994 Haïssaguerre 1996 Jaïs / Haïssaguerre 1997/8 Haïssaguerre 2000 Pappone 2000 Lin 2003 Maroucche / Natale 2004 Ouyang / Kuck 2004 Nademanee 2004 Jaïs / Hocini 2004/5 Pappone 2004
1998: Ablation of PV Foci
Spontaneous Initiation of Atrial Fibrillation by Ectopic Beats Originating in the Pulmonary Veins
Haïssaguerre, M, Jaïs, P, Shah, DC, et al.
N Engl J Med (1998) 339: 659 • Pivotal study identifying the pulmonary veins as a major source of ectopic electrical activity • Radiofrequency ablation of ectopic foci was associated with a 62% success rate (absence of recurrence at 8 6m follow-up)
A Combination of Techniques may now be used Depending on the Type of AFib AFib Trigger Ectopic Foci Substrate Atrial tissue Autonomic Nervous System PV & non-PV Foci Ablation, PV Isolation Vagal Denervation
(parasympathetic ganglia ablation)
CFAEs Ablation Linear Lesions
(e.g. mitral isthmus, roof)
Cardiac Imaging Techniques
•
Electroanatomical mapping
– C ARTO ™ / C ARTO M ERGE ™ •
Fluoroscopy
•
Angiography
•
Intracardiac echography
•
Cardiac spiral CT
•
Cardiac MRI
C
ARTO
™ System
– Localization of catheter to within 1 mm – Increase safety margin during ablation • 3D-electroanatomic maps (C ARTO ™) showing ablation points encircling PVs
PV Antrum Isolation Guided by C ARTO M ERGE ™ Image Integration Software Module LUPV LLPV LA RUPV RMPV AC RLPV
Courtesy of Professor Antonio Raviele, Mestre, Italy
Catheter Visualization under Fluoroscopic Guidance Ablation catheter L ASSO ® LAO RAO
Efficacy and Safety of Catheter Ablation
Meta-analysis of Catheter Ablation
Ablation method Linear Focal Isolation Circumferential (all) Circumferential (LACA, WACA) Circumferential (PVAI) Substrate ablation (CFAE) TOTAL
Patients
443 508 2,187 15,455 2,449 11,132 559 23,626
Paroxysmal AF
75% 81% 83% 68% 65% 68% 51% 61%
SHD
26% 35% 36% 37% 37% 42% 49% 55%
6-month cure
33%
6-months OK
55% 54% 62% 71% 75% 64% 59% 67% 75% 63% 74% 72% 76% 87% 75%
Cure (by each author’s criteria) means no further AFib 6 months after the procedure in the absence of AAD.
OK means improvement (fewer episodes, no episodes with previously ineffective AAD).
SHD indicates structural heart disease.
Fisher JD, et al.
PACE
(2006) 29: 523
Worldwide Survey on Efficacy and Safety of Catheter Ablation for AFib
•
Total success rate: 76%
• Of 8745 patients: – 27.3% required 1 procedure – 52.0% asymptomatic without drugs – 23.9% asymptomatic with an AAD within <1 yr •
Outcome may vary between centres
Cappato R, et al.
Circulation
(2005) 111: 1100
Improved Survival with Ablation vs Drug Treatment
• 589 ablated patients compared with 582 on AADs Ablation Group Medical Group 100 90 80 Expected Observed 70 60 0 0 One-sample log-rank test Obs=36, Exp=31, Z=0.597, p=0.55
180 360 540 720 900
Days of follow-up
1080 0 One-sample log-rank test Obs=79, Exp=341, Z=7.07, p<0.001
180 360 540 720
Days of follow-up
900 1080 Pappone C, et al.
J Am Coll Cardiol
(2003) 42: 185
More AFib-free Patients with Catheter Ablation vs Drug Treatment
100 80 60 40 Ablation Group Medical Group 20 0 0
No. at risk
Ablation Medical
589 582 507 456
100
479 354
200 Follow-up (days)
379 282 277 207 217 141
300
135 97
Pappone C, et al.
J Am Coll Cardiol
(2003) 42: 185
Randomised Clinical Trials of Catheter Ablation RF ablation vs AAD as first-line treatment for AFib
• Wazni OM et al. JAMA (2005) 293: 2634-2640
Catheter ablation in drug-refractory AFib
• Stabile G et al. Eur Heart J (2006) 27: 216-221
Circumferential PV ablation for chronic AFib
• Oral H et al. N Engl J Med (2006) 354: 934-941
RF Ablation vs Antiarrhythmic Drugs as First-line Therapy
• Patients randomised to receive ablation (n=33) or AADs (n=37): AFib-free Survival 1.0
0.8
0.6
0.4
PVI Group Antiarrhythmic Drug Group 0.2
0 0 100 Follow-up (days) 200 300 Wazni OM, et al.
JAMA
(2005) 293: 2634
Catheter Ablation vs. AADs Alone in Drug-refractory AFib
AADs plus ablation (n=68) or AADs alone (n=69): 1 year follow-up 100 80 60 40 20 0 0 1 2 Ablation Group Medical Group 3 4 5 6 7
Months
8 9 10 11 12 Stabile G, et al.
Eur Heart J
(2006) 27: 216
Randomized Controlled Trial of Amiodarone + Cardioversion + Catheter Ablation
Amiodarone & cardioversion (n=69) vs. amiodarone & cardioversion plus PV ablation (n=77) 100 Circumferential pulmonary-vein ablation Control 80 60 40 20 0 1 2 3 4 5 6 7
Months
8 9 10 11 12 Oral H, et al.
N Engl J Med
(2006) 354: 9
Catheter Ablation is Successful in the Long Term
1.0
0.8
0.6
0.4
0.2
0 0 2 No ERAF ERAF 4 6 8
Months after PV isolation
10 12 Oral H, et al.
J Am Coll Cardiol
(2002) 40: 100
Complications Centres Reported by Leading
Major complications with pulmonary vein ablation in 1039 patients (6 series) Complication Events (n) Rate (%)
Transient ischaemic attack 4 0.4
Range in studies (%)
0 - 3 1 0.1
0 - 1 Permanent stroke Severe PV stenosis
(>70%, symptomatic)
Moderate PV stenosis
(40-70%, asymptomatic)
Tamponade / perforation Severe vascular access complication 3 13 5 3 0.3
1.3
0.5
0.3
0 - 3 0 - 5 0 - 3 0 - 4
Verma A & Natale A
Circulation
(2005) 112: 1214
Cost Effectiveness Analyses of Catheter Ablation
Catheter Ablation May Be More Cost effective than Pharmacological Therapy
After 5 years, the cost of RF ablation was below that of medical management and further diverged thereafter
118 patients with symptomatic, drug-refractory AFib
1.52 ± 0.71 ablation procedures
32 weeks Pharmacological treatment
€1590/year
Catheter ablation
€4715 followed by €445/year Weerasooriya R, et al.
Pacing Clin Electrophysiol
(2003) 26: 292
Differences in Hospital Visits and Costs with and without Catheter Ablation
Although the initial cost of ablation is high, after ablation, utilization of healthcare resources is significantly reduced
Clinical visits per year Emergency room visits per year Hospitalization days per year Healthcare costs per year
No ablation 7.4 (2.5) 1.7 (0.9) 1.6 (0.8) $1920 (889) Catheter ablation 1.1 (0.6) 0.03 (0.17) 0 (0) $87 (68) Goldberg A, et al.
J Interv Card Electrophysiol
(2003) 8: 59
Catheter Ablation Cost-Effective in Patients at High Risk of Stroke
Model to compare the cost-effectiveness of left atrial catheter ablation (LACA), amiodarone, and rate control therapy in the management of AFib The use of LACA may be cost-effective in patients with AFib at moderate risk for stroke This model did not find it to be cost-effective in low-risk patients. Conclusions Cost-effective in patients at moderate or high risk of stroke Chan DP, et al.
J Am Coll Cardiol
(2006) 47: 2513
Current Guidelines and Summary
Current ACC/AHA/ESC Guidelines
Recurrent Paroxysmal AF Minimal or no symptoms Disabling symptoms in AF Anticoagulation and rate control as needed No drug for prevention of AF Anticoagulation and rate control as needed AAD therapy AF ablation if AAD treatment fails
ACC/AHA/ESC 2006 Guidelines for the Management of Patients With Atrial Fibrillation
J Am Coll Cardiol
(2006) 48: 854
Recent Commentary
Why Ablation for AFib might be Considered First Line Therapy for Some Patients
“Current therapies, especially AAM, not only are ineffective but also pose a threat to patient QoL and even longevity.
In the hands of experienced operators, AF ablation is an effective, safe, and established treatment for AF that offers an excellent chance for a lasting cure … unlike other therapies, ablation tackles AF at its electrophysiological origin.” Verma A & Natale A
Circulation
(2005) 112: 1214
Summary of catheter ablation (I)
• Catheter ablation for AFib has undergone significant methodological and technical revolution since its initial appearance two decades ago • Discovery that PVs are a major source of ectopic triggers was pivotal in determining efficacy of procedure • Significant technological advances in catheters and imaging are further improving the efficiency of catheter ablation • 3D reconstructions of actual left atrial PV anatomy using CT, MRI, or intracardiac echography enables ever more accurate placement of lesions
Summary of catheter ablation
• High success rate • Improves survival, cardiac function and freedom from recurrence • New data from RCTs confirm benefits • Safe, with a risk comparable to other low-risk, routine interventions • Cost effective compared to standard pharmacological therapy, at least in patients at moderate thromboembolic risk