Discussion
LAA aneurysm is an extremely rare entity. It has slight female
preponderance and is usually diagnosed in the third decade of
life.1 It is often discovered incidentally on imaging
studies in the absence of symptoms.2 LAAA is
classified as congenital or acquired with >90% of the
cases being congenital thought to arise from congenital dysplasia of the
pectinate muscles.2 It is rarely associated with other
cardiac anomalies such as atrial or ventricular septal
defect.1,2 Acquired causes of LAAA include mitral
valve disease or elevated left atrial pressure.2
Most common symptoms associated with LAAA include palpitations and
dyspnea.1 Other symptoms include chest pain and
systemic thromboembolism. Significantly enlarged LAA provides a
substrate for atrial or supraventricular tachyarrhythmias such as SVT,
atrial tachycardia, fibrillation or flutter, which manifest as
palpitations. Aneurysmal dilatation of the LAA results in stasis of
blood and predisposes to thrombus formation. Additionally, these
patients are at high risk of developing atrial fibrillation or flutter
which further increases thromboembolic risk.1 The
incidence of stroke or systemic thromboembolism in LAAA ranges from
6-16%.1,2 Rarely, a large LAAA compresses the
coronary arteries resulting in myocardial ischemia presenting as
angina.3
LAAA is usually diagnosed with multimodality imaging including
echocardiography, CT and MRI. Notably, in large LAA aneurysms, chest
X-ray is abnormal with cardiomegaly and enlarged left heart border
[Figure 2].1 TTE is useful as an initial tool for
evaluation of LAAA.4 Transesophageal echocardiography
is valuable for thrombus detection.5 Contrast
echocardiography aids in confirming the diagnosis as well as ruling out
thrombus formation.4 CT diagnoses LAAA with a high
degree of accuracy and offers additional advantage of assessing coronary
anatomy.2
Surgical resection remains the cornerstone of therapy for LAAA. Early
surgical intervention is recommended given the risk of thromboembolic
complications.6 Median sternotomy is the preferred
surgical approach in majority (85%) of the cases.2Other less invasive approaches such as left lateral thoracotomy,
mini-thoracotomy and endoscopic resection have been
described7-9, however, these approaches are more
suited for smaller aneurysms without intra-aneurysmal thrombi.
Additionally, there is risk of incomplete closure with minimally
invasive approach.9 Therefore, for large LAAA (such as
in our case) median sternotomy with CPB is recommended to minimize the
risk of thromboembolic complications resulting from dislodgement of
small thrombi during surgical manipulation1 and to
provide a clear field to accurately and completely resect the aneurysm
and avoid coronary artery injury [e.g. left circumflex artery located
at the base of LAA].6 After successful surgical
treatment, the prognosis is excellent with freedom from recurrent
symptoms, arrhythmia and thromboembolic events reported in long term
follow-up.1,2