Download An Abnormal Echo-Free Space Behind the Left Atrium

An Abnormal Echo-Free Space Behind the Left Atrium
David Sidebotham, FANZCA, and James Lai, FRCA, FANZCA
A
60-YEAR-OLD MAN presented for coronary artery bypass graft surgery and repair of a left ventricular aneurysm. His past history included coronary artery bypass graft
surgery 7 years previously. Five weeks before his cardiac
operation he suffered a non-ST elevation myocardial infarction
that was complicated by hypotension and required placement of
an intra-aortic balloon pump and intravenous dopamine for 24
hours. Coronary angiography and left ventriculography were
undertaken 4 days after his myocardial infarction. These investigations showed a patent internal mammary graft to the left
anterior descending artery but occluded vein grafts to the
obtuse marginal and posterior descending coronary arteries.
Left ventricular ejection fraction was measured at 50%.
His recovery was complicated by a hospital-acquired pneu-
monia. In addition, he suffered a cerebral transient ischemic
attack and was anticoagulated with coumadin. A transesophageal echocardiogram (TEE) was performed (Figs 1-4). What
was the diagnosis?
Fig 3. Midesophageal aortic valve long-axis view. A large echo-free
space (?) can be seen behind the left atrium. LA, left atrium; LVOT, left
ventricular outflow tract; Asc Ao, ascending aorta; LV, left ventricle.
Fig 1. Midesophageal aortic valve long-axis view. A large echofree space (?) can be seen behind the left atrium. LA, left atrium; AV,
aortic valve; RA, right atrium.
Fig 4. The view is the same as shown in Figure 3. With color
Doppler imaging, flow can be seen within the echo-free space.
Fig 2. The view is the same as shown in Figure 1. With color
Doppler imaging, flow can be seen within the echo-free space.
From the Heart and Vascular Intensive Care Unit, Cardiothoracic
Surgery Service, Auckland City Hospital, Auckland, New Zealand.
Address reprint requests to David Sidebotham, FANZCA, Heart and
Vascular Intensive Care Unit, Cardiothoracic Surgery Service, Auckland City Hospital, 4th Floor, Building 32, Private Bag 92-024, Auckland, New Zealand. E-mail: [email protected]
© 2004 Elsevier Inc. All rights reserved.
1053-0770/04/1805-0025$30.00/0
doi:10.1053/j.jvca.2004.07.021
Key words: transesophageal echocardiography, cardiac surgery,
pseudoaneurysm, acute myocardial infarction, complications
Journal of Cardiothoracic and Vascular Anesthesia, Vol 18, No 5 (October), 2004: pp 671-672
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672
SIDEBOTHAM AND LAI
Fig 5. Modified midesophageal 4-chamber view. The probe has
been advanced slightly from the standard position to display more
posterior structures. An outpouching from the left ventricle (LV) is
seen. The wide neck of the structure is consistent with a true aneurysm (TA). LA, left atrium.
DIAGNOSIS: LARGE ENCAPSULATED PSEUDOANEURYSM
EXTENDING BEHIND THE LEFT ATRIUM
An outpouching (true aneurysm) of the posterolateral wall of
the left ventricle was identified on TEE (Fig 5). At surgery, the
base of the true aneurysm was found to have ruptured forming
an encapsulated pseudoaneurysm that extended behind the left
atrium. The origin of the pseudoaneurysm, in the wall of the
true aneurysm, was not identified on TEE. In fact, the echo-free
space appeared to be limited to the left atrium; as the space was
followed to the level of the posterior atrioventricular groove,
the echo-free space disappeared and an echo-dense area was
seen (Fig 5).
Left ventricular pseudoaneurysm occurs as a consequence of
ventricular free wall rupture, usually secondary to myocardial
infarction. The rupture is contained by adherent pericardium,
thrombus, and scar tissue forming an encapsulated space. Pseudoaneurysm formation more commonly involves the inferior,
Fig 6. Midesophageal 4-chamber view, after cardiopulmonary bypass. The echo-free space has now disappeared. A thinner echodense rim is now seen around the left atrium (LA), consistent with
thrombus. LV, left ventricle; TA, true aneurysm.
posterior, and lateral walls of the heart rather than the anterior
wall,1 and extension behind the left atrium is not well
described.
A number of pathologic conditions can give the appearance
of an echo-free space behind the left atrium2 including fluid in
the oblique pericardial sinus, cor triatriatum, dissection of the
left atrial wall, and a pericardial cyst. In this case, the echo-free
space expanded during systole with evidence of systolic flow
into the space on color Doppler imaging (Figs 2 and 4),
indicating a connection to an arterial or ventricular structure.
These appearances, combined with the preoperative echo findings of a ventricular aneurysm involving the basal posterolateral segments, suggest the correct diagnosis.
The pseudoaneurysm was repaired by simple excision of the
neck and direct closure using felt reinforced mattress sutures.
After separation from CPB, the echo-free space had disappeared (Fig 6), but an echo-dense rim was visible around the
left atrium, probably caused by thrombus.
REFERENCES
1. Yeo TC, Malouf JF, Reeder GS, et al: Clinical characteristics and
outcome in postinfarction pseudoaneurysm. Am J Cardiol 84:592-594, 1999
2. Kluger R: Common diagnostic pitfalls and cardiac masses, in
Sidebotham D, Merry A, Legget M (eds): Practical Perioperative
Transoesophageal Echocardiography. London, England, ButterworthHeinemann, 2003, pp 69-87