Management

3. Thromboembolic Prevention:

Prior thromboembolic disease, heart failure, hypertension, age, diabetes mellitus significantly increase the risk of stroke in both non-valvular and valvular atrial fibrillation by five and seventeen fold respectively.  Several clinical evaluation have been proposed to risk stratify patients according to their risk of having thromboembolic complications.  The most widely used score is the CHADS2.  One point is assigned for each of the risk factors/comorbidities except for a prior stroke or TIA which count for two points.  Anticoagulation with aspirin would be appropriate for any patient with a CHADS2 score of less or equal to 2, while warfarin should be used with a target INR of 2.0 to 3.0 in higher risk patient with a CHADS2 score above or equal to 3.  The choice of anticoagulation should always be patient dependent assessing for the benefit of stroke prevention versus the one of severe bleeding.

Table 5. CHADS2 Score
CHADS2 Risk Criteria
Score
Heart failure (CHF)
1
Hypertension
1
Age (above 75)
1
Diabetes
1
Prior stroke or TIA
2
Total
/6

 

Table 6. Annual Risk of Stroke According to CHADS2 Score
CHADS2 Score
Annual risk of stroke
0
1.9 %
1
2.8 %
2
4.0 %
3
5.9 %
4
8.5 %
5
12.5 %
6
18.2 %

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At time, it may be necessary to interrupt anticoagulation for diagnostic and therapeutic procedure.  It is the consensus that anticoagulation may be interrupted for a period of up to one week without substituting to heparin.  Only patients with mechanical prosthetic heart valves should be breached and substituted to unfractionated or low molecular weight heparin.

 

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