michael s
(Michael S)
#1
73 What are the roles of transthoracic and
transoesophageal echocardiography in patients
with a TIA or stroke?
Diana Holdright
Approximately 80% of strokes are ischaemic in origin, of which
20–40% have a cardiac basis. TIAs have a cardiac cause in ~15%
of cases. Common cardiac abnormalities associated with neuro-
logical events include atrial fibrillation, mitral valve disease, left
atrial enlargement, left ventricular dilatation, prosthetic valve
abnormalities and endocarditis. Clinical examination and simple
tests (CXR and ECG) should indicate cardiac abnormality in these
situations. The aim of echocardiography is to confirm the
presence of important predisposing cardiac abnormalities and in
younger patients, typically <50 years, to look for rare cardiac
causes that might not be detected by other means. This latter
group includes atrial septal aneurysm and patent foramen ovale
(PFO) which, although somewhat controversial, are associated
with an increased risk of stroke in patients without other
detectable abnormalities.
Consequently, echocardiography is particularly useful in
patients at both ends of the age scale. Older patients are more
likely to have cardiac abnormalities that could give rise to
stroke/TIA and young patients frequently have apparently
normal hearts, but echocardiography (especially trans-
oesophageal) may indicate the presence of an atrial septal
aneurysm or PFO. The pick-up rate of transthoracic echocardiog-
raphy is extremely low in patients with a normal clinical exami-
nation, CXR and ECG, making it a poor screening test. Conversely,
the yield in patients with clinical abnormalities or an abnormal
ECG/CXR is high and may give useful information for risk strat-
ification beyond simply confirming a clinical diagnosis, for
example left atrial size and the presence of spontaneous contrast.
Transoesophageal echocardiography should be reserved for
“younger” patients (empirically <50 years) with unexplained
stroke/TIA, for patients in whom the transthoracic study is unclear,
and for older patients with repeated unexplained stroke/TIA.
Transoesophageal echocardiography is particularly useful for
looking at the left atrium, atrial septum, left atrial appendage,
mitral valve and thoracic aorta, abnormalities of which may give
