Clinical utility of echocardiography in secondary ischemic stroke prevention.

Echocardiography employs ultrasound to evaluate cardiac function, structure and pathology. The clinical value in secondary ischemic stroke prevention depends on identification of associated conditions for which a change in treatment from antiplatelet agents and risk factor intervention leads to improved outcomes. Such therapeutically relevant findings include primarily intracardiac thrombus, valvular heart disease and, in highly selected patients, patent foramen ovale (PFO). Echocardiography in unselected patients with ischemic stroke has a very low yield of therapeutically relevant findings and is not cost-effective. With the exception of PFO, findings on echocardiography that are therapeutically relevant for secondary stroke prevention are almost always associated with history, signs or symptoms of cardiac or systemic disease. Choice of specific echocardiographic modalities should be based on the specific pathology or pathologies that are under consideration for the individual clinical situation. Transthoracic echocardiography (TTE) with agitated saline has comparable accuracy to transesophageal echocardiography (TEE) for PFO detection. For other therapeutically relevant pathologies, with the possible exception of left ventricular thrombus (LVT), TEE is more sensitive than TTE. Professional societies recommend TTE as the initial test but these recommendations do not take cost into account. In contrast, cost-effectiveness studies have determined that the most sensitive echocardiographic modality should be selected as the initial and only test.