Atrial fibrillation (AF) is
a risk factor for stroke and is associated with increased mortality. Risk
stratification for ischemic stroke in AF patients is based on scores which
incorporate several risk factors as previous stroke or transient ischemic
attack, age, hypertension, diabetes, and heart failure. Antithrombotic therapy
is tailored according to the level of risk, with vitamin K antagonists (VKA)
reserved to medium-high risk patients. There is good evidence for the benefit
of VKA in preventing stroke and reducing mortality. However, a large proportion
of patients do not receive VKA, mainly due to concerns regarding bleeding complications,
particularly in elderly patients. There are a number of risk factors for stroke
that are not recognized by the risk scores currently in use, as female gender, atherosclerotic
vascular disease, valvular dysfunction and myocardial infarction. Consequently,
the stroke risk in many patients could be underestimated, and these patients
could receive a suboptimal antithrombotic prophylaxis. Several refinements of
current risk scores are in development. Various oral anticoagulants (direct
thrombin inhibitors and direct Factor Xa inhibitors) are available for stroke
prevention in patients with AF overcoming some of the difficulties associated
with VKAs. Advances in identifying patients at risk of stroke and drug
development together may overcome the current difficulties in providing
effective stroke prevention for all patients at risk.
Credits: Maurizio Paciaroni; Giancarlo Agnelli