Elderly patients with atrial fibrillation: oral anticoagulation to prevent cardioembolic stroke

Anticoagulation therapy for thromboembolism prophylaxis in patients with atrial fibrillation (AF) still is a conundrum for many physicians. Age is the most cited argument to withhold anticoagulation, however, because of their higher risk of stroke, elderly patients would have a greater net benefit of antithrombotic therapy compared to younger patients. Dr. Leithäuser, Dr. Park (both Asklepios Clinik Harburg, Germany) and Dr. Jung (Center for Biomaterial Development and Berlin Brandenburg Center for Regnerative Therapies, Teltow, Germany) carried out a detailed and comprehensive review of the risks of cardioembolic stroke and bleeding in patients with AF with and without oral anticoagulation to clarify anticoagulation underuse in the elderly.

AF is the most commonly encountered tachyarrhythmia and poses a serious and growing Public Health issue with increased numbers of affected subjects as population ages (more than 6 million patients in Europe and approx. 2.3 million in the United States). There is a higher prevalence of predisposing conditions in the elderly population, e.g. diabetes, heart failure, hypertension and coronary heart disease. Echocardiography and autopsy studies have shown that more than 90% of all thrombi in patients with AF originated in the left atrium, form in the left atrial appendage.

The risk of stroke varies considerably among the group of patients with AF and there are many ways of classifying stroke, e. g. CHADS 2 score and Stroke Risk in Atrial Fibrillation Working Group schemes. A series of clinical trials (Euro Heart Survey; Copenhagen Atrial Fibrillation Aspirin and Anticoagulation; Canadian Fibrillation Anticoagulation, etc.) have shown the remarkable efficacy of anticoagulation with warfarin compared to placebo in reducing stroke risk in this patient population, nevertheless oral anticoagulation with warfarin or other vitamin K-antagonists remains underused in clinical practice.

Barriers to the prescription of these drugs that were identified from review of the literature were:

- Withholding therapy due to age
- Relative contraindication due to patient noncompliance
- Risk for embolism relative to hemorrhage was judged to be lower

The most feared bleeding complication associated with oral anticoagulation is intracranial hemorrhage.

Difficulties in anticoagulation treatment may be overcome by establishing fully validated risk prediction schemes with large prospective cohorts of AF patients and the development of new anticoagulants that do not require regular monitoring and which have fewer drug interactions. A nonpharmacologic approach may be the exclusion of the LAA cavity from circulation either by surgical or by percutaneous catheter-based procedures.

Despite conclusive evidence from randomised controlled clinical trials, the use of oral anticoagulation in these patients seems to be suboptimal probably due to both, the real-world limitations of warfarin and the disregard for risk guided treatment. Furthermore, prophylaxis should be better tailored to the patient’s individual risk profile to balance risk of thrombosis/embolism and risk of bleeding.