CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 4, May 2012
AFRICA
e5
of the circumflex artery bypass with saphenous vein graft,
aorta–right coronary artery bypass with sapheneous vein graft)
(cardiopulmonary bypass time: 123 min, total circulatory arrest
time at 18°C: 25 min, cross-clamp time: 81 min).
After distal coronary anastomoses, a segment from the
supracoronary aorta to the left subclavian artery ostium was
excised and the hemi-arcus was replaced with a number 28
gel-coated dacron vascular graft. Lastly, proximal coronary
anastomoses of the saphenous grafts were performed directly to
the aortic graft (Fig. 3). No operative/postoperative embolic or
other complications were experienced following the successful
operation.
Pathological examination of the specimen revealed
macroscopically: rupture of the tunica intima, an atheromatous
plaque with ulceration, and a pedunculated thrombus formation
attached to the arterial wall, and microscopically: atherosclerotic
intimal changes, chronic fibrosis, and full-thickness degeneration
of the artery (Fig. 4). The patient was discharged from the ICU
on the third postoperative day and from hospital on the 15th
postoperative day. The patient presented for routine cardiology
and cardiovascular surgery follow up without any complaints.
Discussion
Although several variables were identified as risk factors for
peri-operative stroke, the majority of strokes occur in patients
where no definitive aetiological factors can be identified. All
patients undergoing cardiac surgery may have atherosclerotic
aortic plaques with no clinical evidence, and these are a potential
source of serious peri-operative or postoperative athero-embolic
complications. Thorough pre-operative echocardiographic
evaluation of the patient, and particularly of the elderly, is crucial
for an uneventful surgical outcome.
TTE compares favourably with TEE in the identification of
atheromatous plaques of the aortic arch and distal ascending
aorta, although it is less effective in identifying simple plaques
of the proximal ascending aorta. The demonstration of aortic
plaque with TEE has a sensitivity of 91%, specificity of 82%,
and positive and negative predictive values of 72 and 95%,
respectively.
8
However, TEE, which is a sensitive technique to
determine protruding aortic atheromas with or without a mobile
component, cannot always visualise plaques located in the distal
ascending aorta and proximal aortic arch.
9
Weinberger
et al
. reported that TTE could be used to visualise
plaques in the distal ascending aorta and aortic arch, and
particularly plaques at the junction of the ascending aorta and
aortic arch that could be obscured by the bronchi and may be
missed byTEE.
9
TTEwas able to detect simple plaques undetected
with TEE, particularly in the proximal ascending aorta. Konstadt
et al
. reported that up to 42% of the ascending aorta cannot
be visualised by TEE, so potential embolic plaques can be
missed by that modality.
10
All complex plaques, morphologically
similar and visualised with TEE were also demonstrated with
TTE. Both techniques are able to identify the plaques as
pedunculated or proliferative and to picture their mobility.
To our knowledge, there is no study comparing TTE
with TEE in detecting mobile atheromatous plaques. Most
echocardiographers feel that TEE is more accurate than TTE
for the critical measurement of plaque thickness and for the
diagnosis of mobile thrombi (high resolution and proximity
to the aorta). The small portion of the ascending aorta that is
masked by the trachea near the origin of the innominate artery
may not be seen on TEE and only 2% of the plaques may be
missed with this modality.
11
As a significant proportion of aortic plaques of stroke
patients can be demonstrated with TTE, the necessity for a
TEE evaluation, which is a relatively invasive procedure, will
automatically diminish. Unfortunately, combined TEE and TTE
examinations of the aortic arch may still be mandatory in a
subgroup of patients, to rule out the presence of atherosclerotic
plaque. TTE imaging of the aortic arch is also useful for
sequential evaluation of the plaques already identified with
TEE, and therefore helps physicians to omit repetitive TEE
examinations.
Conclusion
Routine TTE evaluation is a valuable modality, particularly for
elderly candidates, for aortic cannulation in open-heart surgery.
In our case, the pre-operative TTE examination of the patient
enabled the surgeon to make the correct and custom-designed
operative decision, which assured a safe procedure and better
surgical outcome.
References
1.
Sharifkazemi MB, Aslani A, Zamirian M, Moaref AR. Significance of
aortic atheroma in elderly patients with ischemic stroke. A hospital-
based study and literature review.
Clin Neurol Neurosurg
2007;
109
(4):
311–316.
2.
Tunick PA, Kronzon I. Atheromas of the thoracic aorta: clinical and
therapeutic update.
J Am Coll Cardiol
2000;
35
(3): 545–554.
3.
Barbut D, Lo YW, Hartman GS, Yao FS, Trifiletti RR, Hager DN,
et al
.
Aortic atheroma is related to outcome but not numbers of emboli during
coronary bypass.
Ann Thorac Surg
1997;
64
(2): 454–459.
4.
Tribouilloy C, Peltier M, Colas L, Senni M, Ganry O, Rey JL, Lesbre
JP. Fibrinogen is an independent marker for thoracic aortic atheroscle-
rosis.
Am J Cardiol
1998;
81
(3): 321–326.
5.
Katz ES, Tunick PA, Rusinek H, Ribakove G, Spencer FC, Kronzon
I. Protruding aortic atheromas predict stroke in elderly patients
undergoing cardiopulmonary bypass: experience with intraoperative
transesophageal echocardiography.
J Am Coll Cardiol
1992;
20
(1):
70–77.
6.
Daniel WG, Erbel R, Kasper W, Visser CA, Engberding R, Sutherland
GR,
et al
. Safety of transesophageal echocardiography. A multicenter
survey of 10,419 examinations.
Circulation
1991;
83
(3): 817–821.
7.
Marschall K, Kanchuger M, Kessler K, Grossi E, Yarmush L, Roggen
S,
et al
. Superiority of transesophageal echocardiography in detecting
aortic arch atheromatous disease: identification of patients at increased
risk of stroke during cardiac surgery
. J Cardiothorac Vasc Anesth
1994;
8
: 5–13.
8.
Tribouilloy C, Peltier M, Colas L, Rida Z, Rey JL, Lesbre JP.
Multiplane transoesophageal echocardiographic absence of thoracic
aortic plaque is a powerful predictor for absence of significant coronary
artery disease in valvular patients, even in the elderly. A large prospec-
tive study.
Eur Heart J
1997;
18
(9): 1478–1483.
9.
Weinberger J, Azhar S, Danisi F, Hayes R, Goldman M. A new nonin-
vasive technique for imaging atherosclerotic plaque in the aortic arch:
an initial report of stroke patients by transcutaneous real-time B-mode
ultrasonography.
Stroke
1998;
29
; 673–676.
10. Konstadt SN, Reich DL, Quintana C, Levy M. The ascending aorta:
how much does transesophageal echocardiography see?
Anesth Analg
1994;
78
: 240–244.
11. Krinsky GA, Freedberg R, Lee VS, Rockman C, Tunick PA. Innominate
artery atheroma: a lesion seen with gadolinium-enhanced MR angiog-
raphy and often missed by transesophageal echocardiography.
Clin
Imaging
2001;
25
: 251–257.
