Download Left Atrial Myxoma Associated with Mitral Valve Pathology

Hellenic J Cardiol 2013; 54: 138-142
Case Report
Left Atrial Myxoma Associated with Mitral Valve
Pathology in Pregnancy
Ioannis Koukis, Theodore Velissaris, Alex Pandian
Cardiothoracic Department, Manchester Heart Centre, Central Manchester University Hospitals NHS Foundation
Trust, UK
Key words: Atrial
myxoma, pregnancy,
transthoracic
echocardiography.
We report a case of a left atrial myxoma associated with mitral valve regurgitation in a pregnant patient, describing the importance of transoesophageal or transthoracic echocardiography, preoperatively and during
the operation, as a useful tool to rule out any associated valvular damage or mitral annular dilatation as an
underlying cause of mitral regurgitation.
I
Manuscript received:
January 13, 2011;
Accepted:
July 20, 2011.
Address:
Ioannis Koukis
10 Verginas St.
151 21 Pefki
Athens, Greece
e-mail: [email protected]
ntracardiac myxomas comprise 50%
of all benign cardiac tumours and
have an estimated incidence of 0.5
per million population per year. Although
the vast majority of myxomas (75%) occur in the left atrium, they are infrequently associated with mitral valve pathology.
There have been very few case reports of
left atrial myxoma associated with mitral
valve pathology,1,2 and, to our knowledge,
no such case has been reported in a pregnant patient.
Here we describe the case of a left
atrial myxoma associated with mitral valve
regurgitation in a pregnant patient, stressing the importance of transoesophageal
echocardiography (TOE) or transthoracic
echocardiography (TTE) as a useful tool
to rule out preoperatively and during the
operation any associated valvular damage
or mitral annular dilatation as an underlying cause of mitral regurgitation.
Case presentation
A 29-year-old Ghanaian lady presented
with a 6-month history of palpitations, fatigue and increasing exertional dyspnoea.
She was confirmed 6 weeks pregnant on
ultrasound scan and routine blood inves-
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tigations were all within normal limits.
TTE showed a large pedunculated mass in
the left atrium, attached to the interatrial
septum, with an appearance suggestive of
atrial myxoma. Mild mitral regurgitation
(MR) was noted, which was thought to be
due to the tumour prolapsing through the
mitral valve. Left ventricular and left atrial dimensions were normal and left ventricular systolic function was good, with an
ejection fraction of 60%. The patient was
transferred to our cardiothoracic surgical
centre for urgent surgery.
Intraoperative TOE confirmed the
presence of a mass in the left atrium measuring 3.6 cm × 5.7 cm. The mass was attached to the interatrial septum, slightly
inferior to the fossa ovalis and approximately 1.2 cm from the mitral annulus.
The echocardiographic appearance of the
large mass was typical of atrial myxoma.
(Figure 1). There was mild MR associated
with the prolapse of the tumour through
the mitral valve causing a coaptation defect of the leaflets (Figure 2). There was
thickening and possible calcification of the
anterior (A2, A3) mitral leaflet. There was
no prolapse of the mitral leaflets and the
mitral annulus diameter was measured at
4.1 cm.
Left Atrial Myxoma in Pregnancy
Figure 1. Transoesophageal echocardiogram, four-chamber view,
showing the interatrial mass.
Through a median sternotomy, cardiopulmonary
bypass was established using bicaval cannulation. The
heart was arrested using antegrade cold-blood cardioplegia and the tumour was approached through
a transseptal incision. A large smooth pedunculated
mass with typical external appearances of a myxoma
was encountered and was excised with its stalk from
the interatrial septum (Figure 3). The interatrial septum and the roof of the left atrium were closed with
3-0 prolene and the right atrium was closed with 5-0
prolene. The patient was weaned from cardiopulmonary bypass without any difficulties. Intraoperative
TOE demonstrated no residual left atrial mass and an
intact interatrial septum with no shunting. However
there was severe mitral regurgitation with a posteriorly directed jet (Figures 4 & 5) and a central jet. Thickening of the anterior leaflet and poor coaptation of
the leaflets were noted. There was no mitral valve
prolapse. Mitral annular dilatation was measured at
4.1 cm. The left ventricular function remained good
and the patient maintained excellent haemodynamic
stability.
Given the complex issue of valve choice (mechanical vs. bioprosthetic) in a pregnant woman should a
valve replacement be necessary, and the patient’s excellent haemodynamic stability, it was decided that
the best course of action was to transfer the patient
to the intensive care unit. She was extubated the same
evening and her condition and possible treatment options were discussed with her the next day, when she
had regained complete consciousness. She agreed to
undergo mitral valve repair and receive a bioprosthesis if required. Repeat surgery was performed the following day and the valve was approached using the
Figure 2. Transoesophageal echocardiogram, showing the mass
with mild mitral regurgitation.
Figure 3. Macroscopic view of the left atrial myxoma.
previously performed transseptal incision. The anterior leaflet appeared thickened, with no palpable calcification, and the posterior annulus was dilated. The
left atrium was not enlarged. A 32 mm Cosgrove annuloplasty band was implanted to reduce the size of
the posterior mitral valve annulus. The patient was
weaned from cardiopulmonary bypass easily and repeat TOE showed only mild residual MR (Figure 6).
The patient made an excellent recovery and there
were no complications other than intermittent episodes of complete heart block, for which a permanent pacemaker was implanted three weeks postoperatively. Following that, she was discharged home.
Due to her pregnancy she was not started on warfarin or aspirin and she remained free of thromboembolic incidents throughout her pregnancy. Histology
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I. Koukis et al
Figure 4. Transoesophageal echocardiogram, showing severe mitral regurgitation after tumour removal
Figure 5. Direct trans-gastric basal view of regurgitation.
confirmed an atrial myxoma measuring 5.5 × 2.5 × 4.0
cm. Her pregnancy remained viable and she delivered
a healthy female infant in the 37th week via a caesarean incision. At one-year follow up she remains with
excellent cardiac function and mild MR.
Discussion
The first case of successful surgical excision of left
atrial myxoma was described by Crafoord in 1955.
There are four case reports in the literature of left
atrial myxoma removal during pregnancy.3-6 To our
knowledge, there has been no previous case report of
left atrial myxoma associated with mitral valve pathology in a pregnant patient requiring mitral valve repair.
Primary tumours of the heart are uncommon,
with an estimated incidence of 0.17% to 0.19% in selected autopsy series. Of these tumours, 75% are benign and approximately 50% of these are myxomas.
Myxoma is a neoplasm of unknown histogenesis, occurring most often in middle-aged, usually female
patients, readily amenable to treatment, and with an
excellent postoperative prognosis. Prompt diagnosis
and intervention are important, as potentially fatal
obstructive and embolic complications may occur.
Most myxomas (75%) arise inside the left atrium
from the interatrial septum at the border of the fossa
ovalis. Grossly, about two-thirds of myxomas are round
or oval shaped with a smooth or slightly lobulated surface. Pinede et al, in their case series, reported that the
average size of the myxomas varied from 1 to 15 cm.7
Most patients with myxoma present with symptoms of obstructive mitral valvular disease (mitral stenosis), congestive heart failure, signs of embolisation,
140 • HJC (Hellenic Journal of Cardiology)
Figure 6. Repeat transoesophageal echocardiogram after mitral
annuloplasty, showing mild thickening of the leaflets
systemic or constitutional symptoms of fever, weight
loss or fatigue, and immunological manifestations of
myalgia, weakness, and arthralgia. Central nervous
system symptoms usually call for CT or MRI of the
brain to exclude embolisation or aneurysm formation,
which is sometimes associated with myxomas. It has
been suggested that it is prudent to perform MRI of
the brain in all cardiac myxoma cases to exclude central nervous system manifestations.8
In our case, the patient was a 29-year-old pregnant female who presented with dyspnoea, orthopnoea, paroxysmal nocturnal dyspnoea, fatigue, and
pain in her left arm. The actual dimensions of the tumour were 3.6 cm × 5.7 cm, in accordance with the
usual dimensions described in large series (mean 5
cm). In these aspects, our patient fit within the classic
picture of atrial myxoma.
Left Atrial Myxoma in Pregnancy
There have been two case reports of left atrial
myxoma with annular dilatation in the presence of
left atrial and left ventricular enlargement.1,9 But the
rare feature in our patient was the presence of mitral
annular dilatation without left atrial and left ventricular enlargement. This is an unusual finding and has
rarely been reported previously in the literature.10,11
To our knowledge, this is the first of its kind to be reported in a pregnant patient.
Though mitral regurgitation is a frequent occurrence preoperatively, damage to the mitral valvular
apparatus requiring mitral valve repair or replacement is rare.9-11 The striking feature in our patient
was the acquired structural anomaly of the mitral
valve, namely the posterior annular dilatation without
chamber enlargement. From the TOE after tumour
removal, the mitral regurgitation—which was initially
thought to be due to tumour prolapse into the mitral
valve—was actually mainly due to a coaptation defect
secondary to posterior annular dilatation (Figure 4).
The possible causes of mitral regurgitation in a
patient with left atrial myxoma are tumour prolapse
causing volume overload, leading to left atrial and left
ventricular dilatation and annular dilatation, and possible mechanical trauma to the mitral valve leaflets.7
In our patient the mitral valve looked absolutely normal, apart from mild thickening of the anterior leaflet, and there was no prolapse. The most likely explanation for the annular dilatation in this case might be
the repeated mechanical stretch of the mitral annulus
by tumour prolapse into the mitral valve during systole and diastole (Figures 1 & 2). This patient had worsening dyspnoea with repeated episodes of paroxysmal
nocturnal dyspnoea prior to admission. This could be
due to an increase in cardiac output and blood volume expansion secondary to pregnancy in the presence of severe mitral regurgitation and the tumour
obstruction.
In this patient, TOE played a significant role in
diagnosing the annular dilatation as a cause of mitral
regurgitation. Classical teaching suggests that simple
excision of the left atrial myxoma resolves the symptoms and is usually the only treatment needed. In our
experience this was not the case. It may be prudent
to examine the mitral valve apparatus, irrespective of
the chamber size, and discuss all the possible options
for treatment in relation to the patient’s clinical condition before proceeding with surgical removal. This
examination should be performed either with TTE,
or if need be with TOE, in order to identify the occasional valvular pathology. Thus, the subsequent op-
eration can be planned more accurately. In our case,
despite the definite secondary mitral valve pathology, both chambers were of nearly normal size. To our
knowledge, this is very uncommon.
The patient was not started on either warfarin or
aspirin postoperatively. The decision was based on
her pregnancy status. The current European Society
of Cardiology guidelines support the use of warfarin
for 3 months post-mitral repair, citing an absence of
studies supporting the safety of omitting warfarin.10
Thus the decision was not fully justified, but the patient remained free of thromboembolic incidents and
the infant was a healthy one.
The authors conclude that TOE is an invaluable
tool in the diagnosis and understanding of the exact
location of the neoplasm, associated mitral valve pathology, and the diagnosis and mechanism of mitral
regurgitation after excision of a myxoma. Prompt understanding of the integrity of the mitral valve apparatus should be acquired before the operation, using
either TOE or TTE, so that the surgical procedure
may be planned accordingly. With hindsight, the other lesson to learn is that it may be prudent to examine
the mitral valve apparatus as a routine procedure after tumour excision and discuss with the patient the
possibility of mitral valve repair, with or without valve
replacement, before proceeding with left atrial myxoma excision.
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