Can echocardiography improve the prediction of thromboembolic risk in atrial fibrillation? Evidences and perspectives

Atrial fibrillation is the most common arrhythmia and its prevalence is expected to further increase. Patients with atrial fibrillation have an increased risk of stroke (fivefold increased risk), heart failure, and death. In patients with non-valvular atrial fibrillation, the most recent guidelines recommend the use of the CHA2DS2-VASc (congestive heart failure, arterial hypertension, age > 75 years, diabetes mellitus, stroke/transient ischemic attack, vascular disease, age 65–74 years, sex category) scoring system to identify those who may benefit from oral anticoagulant treatment. Guidelines recommend initiation of oral anticoagulation with vitamin K antagonists or direct oral anticoagulants in men with a score ≥ 2 and in women with a score ≥ 3, while oral anticoagulation in individuals with a score of 0 is not recommended. Accordingly, men with CHA2DS2VASc score = 1 (and women with CHA2DS2VASc = 2) represent a grey zone where guidelines do not provide a definite oral anticoagulant indication. Implementation of risk stratification with transthoracic echocardiography could be extremely useful. Both prospective and observational studies using transthoracic echocardiography prediction of events and studies utilizing transesophageal echocardiographic parameters as surrogate markers of thromboembolic events make sustainable the hypothesis that echocardiography could improve thromboembolism prediction in non-valvular atrial fibrillation. However, because of some controversial results of different studies, determination of the best echocardiographic parameter predicting thromboembolic events in atrial fibrillation remains uncertain. The combination of left atrial enlargement with left atrial function (in particular assessing left atrial strain) appears to be very valuable, but needs to be confirmed in large-scale multi-center trials.