Atrial Fibrillation Warfarin and its newer alternatives

Dr Mark Abelson

Cardiologist

Somerset West

MM00453 (01) Intl 06/09

Association of AF and Stroke

Occluded Left ICA-T Pre and Post Embolectomy

54y M, “Wake up” >4h,NIHSS=32 MRS=1 @ 90 d

Carotid Embolectomy

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

AF and Stroke

-- 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

CHADS(2) Score CHADS

Congestive heart failure

+1

Hypertension +1

Age 75> +1

Diabetes Mellitus

+1

Stroke or History of Cerebral Ischemia

+2 0.8%2.2%

4.5%

8.6%

10.9%12.3%

13.7%

0.0%

5.0%

10.0%

15.0%

20.0%

0 1 2 3 4 5 6

F GAGE et al., 2004; 110:2287-2292

Annual Stroke Risk for Patients with AFBy CHADS(2) Score

Risk Stratification and Annual Stroke Risk for Patients with AF

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 (2)

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

Currently Available Management OptionsClot Prevention

Warfarin Therapeutic Window - INR of 2 to 3

A small window: difficult to achieve a well controlled therapeutic range

0 20 40 60 80 100

INR Control – Not Good

3000838-14

%%

Bungard: Pharmacotherapy 20:1060, 2001Bungard: Pharmacotherapy 20:1060, 2001

Low INR <1.6Low INR <1.6

TherapeuticTherapeuticINR 2-3INR 2-3

High INR >3.2High INR >3.2

Efficacy Efficacy 4-fold 4-fold

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

Currently available in limited markets

AMPLATZER® Cardiac Plug WATCHMAN®

Transcatheter Occlusion of the LAALeft Atrial Appendage Occluders

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.