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[Atrial fibrillation and thromboembolic events prevention. State of the art]
S Matteoli1, M Trappolini, F M Chillotti
1Dipartimento di Scienze Cliniche, Università degli Studi La Sapienza, Rome, Italy.
Insights
Atrial Fibrillation (AF) patients face a high stroke risk. Warfarin significantly reduces this risk, while aspirin offers less benefit for high-risk individuals. Careful patient selection for anticoagulation is crucial.
Area of Science:
- Cardiology
- Neurology
- Pharmacology
Background:
- Atrial Fibrillation (AF) is a common arrhythmia with a six-fold increased risk of ischemic stroke.
- Stroke risk in AF patients is influenced by coexisting cardiovascular diseases, necessitating risk stratification for antithrombotic prophylaxis.
Purpose of the Study:
- To review the efficacy of antithrombotic therapies for stroke prevention in Atrial Fibrillation patients.
- To guide the selection of appropriate antithrombotic prophylaxis based on individual stroke risk.
Main Methods:
- Systematic review of prospective studies and randomized clinical trials.
- Analysis of factors independently predictive of stroke in AF patients.
- Evaluation of warfarin and aspirin efficacy and safety profiles.
Main Results:
- Warfarin therapy reduces stroke risk by approximately two-thirds in AF patients.
- Aspirin shows a controversial but statistically significant 21% stroke risk reduction.
- Prior TIA/stroke, diabetes, age, heart failure, and left ventricular dysfunction are key stroke predictors.
Conclusions:
- Anticoagulation therapy, particularly warfarin, is recommended for high-risk AF patients, with a target INR of 2.5.
- Aspirin is suitable for low-risk patients or those unable to take anticoagulants.
- Combination therapy with aspirin and low-dose warfarin offers no additional benefit and should be avoided.
Abstract:
Atrial Fibrillation (AF) is a common cardiac arrhythmia and stroke is its most devasting complication. The rate of ischemic stroke among people with AF is approximately six times that of people without AF and varies importantely with coexistent cardiovascular diseases; therefore stratification of AF patients into those at high and low risk of thromboembolism has become a crucial determinant of optimal antithrombotic prophylaxis. Multivaria-te analyses of prospective studies consistently show prior TIA/stroke, diabetes, age, heart failure to be independently predictive of stroke; left ventricular dysfunction is also strongly associated with stroke risk. Several randomized clinical trials demonstrated that treatment with adjusted-dose warfarin reduces the risk of stroke in AF patients by about two thirds. The efficacy of aspirin for prevention of stroke is controversial, but supported by pooled results of 3 placebo-controlled trials yelding a 21% reduction in stroke. The inherent risk of stroke should be considered in selection of AF patients for lifelong anticoagulation. Patients with AF and a recent stroke or TIA or multiple risk factors for stroke are likely to benefit from anticoagulation therapy; at present a target INR 2,5 appears optimal for most patients, although INR closer to 2.0 may be safer for patients at increased risk for bleeding events. The addition of aspirin to low- dose warfarin regimen does not provide any significant benefits and should be avoided. Therapy with aspirin is appropriate for patients who are at low risk of stroke or are unable to receive anticoagulants. AF patients treated with aspirin, should be periodically evaluated for development of high-risk features favoring anticoagulation.