Atrial Fibrillation
Warfarin and its newer alternatives
Dr Mark Abelson
Cardiologist
Somerset West
Association of AF
and Stroke
MM00453 (01) Intl 06/09
Occluded Left ICA-T Pre and Post
Embolectomy
54y M, “Wake up” >4h,NIHSS=32
MRS=1 @ 90 d
Carotid Embolectomy
AF and Stroke
Atrial Fibrillation and Stroke
 3 million in US and 4.5 million in the EU have
AF
 2/3 of AF population are at high-risk of stroke
 AF is responsible for 15-20% of ischemic
strokes
 AF Incidence increases with age
-- 0.4% in general population
-- 0.2% of 25-34 yrs of age
-- 2-5% of >60 yrs of age
-- 10% of > 80 yrs of age
Relationship of AF and Stroke
Risk Stratification and Annual Stroke Risk for Patients with AF
Annual Stroke Risk for Patients with AF
By CHADS(2) Score
CHADS(2) Score
CHADS
Congestive
heart failure
+1
Hypertension
+1
Age 75>
+1
Diabetes
Mellitus
+1
Stroke or
History of
Cerebral
Ischemia
+2
20.0%
13.7%
15.0%
12.3%
10.9%
8.6%
10.0%
4.5%
5.0%
2.2%
0.8%
0.0%
0
1
2
3
4
F GAGE et al., 2004; 110:2287-2292
5
6
Clot Prevention
Currently
Available Management Options
Medical Management: Anticoagulant




Effective: 67% stoke risk reduction(1)
Narrow therapeutic window for proper dose
Contraindicated in 14-47% of patients at risk of stroke
Major complication: bleeding
Surgical Excision (Appendectomy)




Residual shunt: 10% (3)
Inconsistent outcomes due to incomplete exclusion;
Can create pouch with stagnant blood flow (4,5)
High invasiveness
Transcatheter Device Closure



Minimally invasive nature
Designed for percutaneous closure of the LAA in
prevention of clot embolization that may form in the
LAA
Intended as an alternative to warfarin therapy for
patients with non-valvular atrial fibrillation
(2)
Warfarin Therapeutic Window - INR of 2 to 3
A small window:
difficult to
achieve
a well controlled
therapeutic
range
INR Control – Not Good
Low INR <1.6
Efficacy  4-fold
Therapeutic
INR 2-3
High INR >3.2
0
20
40
60
80
100
%
Bungard: Pharmacotherapy 20:1060, 2001
3000838-14
New Warfarin Alternatives
• NO INR monitoring
- Dabigatran ( Pradaxa) – direct thrombin
inhibitor
- Rivaroxaban (Xarelto) – F10a inhibitor
• Aspirin plus clopidogrel
• Aspirin (reduces stroke risk by 20%)
Risk of Stroke or Embolism
Connolly SJ et al. N Engl J Med 2009;361:1139-1151.
Can’t Take Warfarin??
•
•
•
•
•
•
Frail, falls
GI bleeds
Cerebral bleeds
Stroke despite therapeutic warfarin
Non-compliant / labile INR
(Do not want warfarin)
90% of clots in appendage
Transcatheter
Occlusion
of the LAA
Left Atrial
Appendage
Occluders
Currently available in limited markets
AMPLATZER® Cardiac Plug
WATCHMAN®
Protect AF – 21month F/U
Vergelegen Experience
•
•
•
•
7 patients – all elderly men with Chads>2
Significant GI bleeds on warfarin
Warfarin stopped – 2 had small strokes
One INR very labile due to recurrent UTI
(antibiotics. Suprapubic catheter)
• All discharged next day – ASA and plavix for 1
month then ASA alone.