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Cardiac Surgery: Answers
149
proportion of transfused
patients. However, the ISPOT meta-analysis suggested that patients
taking aspirin may benefit from desmopressin, but this is uncertain.
References
Ozier Y, Schlumberger S. Pharmacological approaches to reducing blood loss and
transfusions in the surgical patient. Can J Anaesth. 2006;53(6 Suppl):S21-9.
Laupacis A, Fergusson D. Drugs to minimize perioperative blood loss in cardiac surgery:
meta-analyses using perioperative blood transfusion as the outcome. The International
Study of Perioperative Transfusion (ISPOT) Investigators. Anesth Analg. 1997;85:1258-
67.
Levi M, Cromheecke ME, de Jonge E, et al. Pharmacological strategies to decrease excessive
blood loss in cardiac surgery: a meta-analysis of clinically relevant endpoints. Lancet.
1999;354:1940-7.
2.5 Answer: D
Antifibrinolytic agents are commonly used during
cardiac surgery to minimize bleeding
and to reduce exposure
to blood products. The BART trial was undertaken to determine
whether aprotinin
was superior to either tranexamic acid or aminocaproic acid
in decreasing
massive postoperative bleeding and other clinically
important consequences.
In this multicenter, blinded trial, 2331 high-risk cardiac surgical patients were randomly
assigned to one of three groups:
781 received aprotinin, 770 received tranexamic acid, and
780
received aminocaproic acid. The primary outcome was massive
postoperative bleeding.
Secondary outcomes included death from
any cause at 30 days.
The trial was terminated early because of a higher rate
of death in patients receiving
aprotinin. A total of 74 patients
(9.5%) in the aprotinin group had massive bleeding, as
compared
with 93 (12.1%) in the tranexamic acid group and 94 (12.1%)
in the aminocaproic
acid group (relative risk in the aprotinin
group for both comparisons, 0.79; 95% confidence
interval [CI],
0.59 to 1.05). At 30 days, the rate of death from any cause
was 6.0% in the
aprotinin group, as compared with 3.9% in the
tranexamic acid group (relative risk, 1.55; 95%
CI, 0.99 to
2.42) and 4.0% in the aminocaproic acid group (relative risk,
1.52; 95% CI, 0.98 to
2.36). The relative risk of death in the
aprotinin group, as compared with that in both groups
receiving
lysine analogues, was 1.53 (95% CI, 1.06 to 2.22).
The authors of the BART trial concluded that despite the possibility of a modest
reduction in
the risk of massive bleeding, the strong and consistent negative
mortality trend
associated with aprotinin, as compared with
the lysine analogues, precludes its use in high-
risk cardiac
surgery.
References
Fergusson DA, Hébert PC, Mazer CD, et al., BART investigators. A comparison of aprotinin
and lysine analogues in high-risk cardiac surgery. N Engl J Med. 2008;358:2319-2331.
2.6 Answer: E
Cardiac papillary fibroelastoma (CPF) is a collection of avascular fronds
of dense
connective tissue lined by endothelium. As with
myxoma, the cause of fibroelastoma is not
clear. Some authors
believe that fibroelastoma is a reactive process, whereas others
believe it
Shahzad G. Raja
150
is a hamartoma. Synonyms include fibroelastic
papilloma, papilloma of valves, giant Lambl
excrescence, myxofibroma,
myxoma of valves, hyaline fibroma, and fibroma of valves.
The reported prevalence of papillary fibroelastoma varies. Because
they are usually
asymptomatic, papillary fibroelastomas are
likely underrepresented in surgical series, and
there have been
several large surgical series in which they did not appear at
all. However, in
surgical series at the Mayo Clinic
and the Armed Forces Institute of Pathology (AFIP), they
represented 10% of all primary cardiac
tumors and were the second most common benign
primary cardiac
neoplasm after myxoma. When symptoms are present, they are usually
related
to embolization from thrombi that collect on the tumours. Right-sided fibroelastomas are
usually asymptomatic.
Fibroelastomas are equally common in men and women, with the
mean
age at presentation being about 60 years.
At gross examination, the tumours are small (usually less than
1 cm in diameter),
although they have been reported as
large as 5 cm. They are composed of delicate, frondlike
excrescences attached to the endocardium by a short pedicle
and are often likened to a sea
anemone. Over 90% occur on
valve surfaces, making them by far the most common primary
cardiac
tumour to occur on valves. They are slightly more common
on the aortic (29%) and
mitral (25%) valves than on the pulmonary
(13%) and tricuspid (17%) valves, although this
reported
predilection may be due to the increased prevalence of symptoms
associated with
left-sided fibroelastomas. About 16% of the
tumours arise from nonvalvular surfaces.
Calcification rarely
occurs, having been reported in only two cases. The tumours
are usually
isolated, although in one series, three of 17 patients
with histologically proved papillary
fibroelastoma had multiple
tumors.
Fibroelastomas are easily detected at echocardiography, where
they appear as small,
mobile masses attached to valves by a
short pedicle. They may appear as elongated strandlike
projections
or may have a well-defined "head". Fibroelastomas have
a stippled edge with a
"shimmer" or "vibration" at the interface
of the tumour with the surrounding blood. This has
been
reported as a characteristic feature of fibroelastomas, helping
distinguish them from the
more amorphous thrombi.
Although fibroelastomas are well visualized at echocardiography,
they are usually not
seen at CT or MR imaging because they are
small and are attached to moving valves. With
current technology,
CT and MR imaging will probably reliably help detect only exceptionally
large fibroelastomas or the atypical fibroelastomas that occur
away from the valves.
Surgical excision of CPF is curative, and in most cases, the tumours can be easily
removed because they are pedunculated. Therefore, the treatment of choice for symptomatic
CPF is surgical excision. The root of the pedicle and the full thickness of endocardium
involved is excised, and any resulting defects is closed by direct suturing or, if too large, with
a pericardial or Dacron patch. Care is taken to avoid intraoperative fragmentation of the
tumour and embolism. All chambers of the heart are inspected to rule out multiple tumours.
Mechanical damage to a heart valve or adhesion of the tumour to valve leaflets may call for
valve repair or replacement. The short- and long-term prognosis after surgical removal is
excellent. Recurrence after surgical resection has not been reported; the longest follow-up
reported is of 11 years. Tumour mobility is an independent predictor of occurrence of death or
nonfatal embolization.
Cardiac Surgery: Answers
151
References
Ngaage DL, Mullany CJ, Daly RC, et al. Surgical treatment of cardiac papillary
fibroelastoma: a single center experience with eighty-eight patients. Ann Thorac Surg.
2001;80:1712-1718.
Gowda RM, Khan IA, Nair CK, et al. Cardiac papillary fibroelastoma: a comprehensive
analysis of 725 cases. Am Heart J. 2003;146:404-410.
Shahian DM. Papillary fibroelastomas. Semin Thorac Cardiovasc Surg. 2000;12:101-110.
Sun JP, Asher CR, Yang XS, et al. Clinical and echocardiographic characteristic of papillary
fibroelastoma: a retrospective and prospective study in 162 patients. Circulation.
2001;103:2687-2693.
Grandmougin D, Fayad G, Moukassa D, et al. Cardiac valve papillary fibroelastomas:
clinical, histological and immunohistochemical studies and a physiopathogenic
hypothesis. J Heart Valve Dis. 2000;9:832-841.
2.7 Answer: D
Cardiac sarcomas are the most common primary malignant tumour
of the heart and
pericardium. They are rare neoplasms, with
a prevalence of 0.001%–0.3% in autopsy series. It
is worth noting that cardiac metastases are 20–40 times
more common than primary cardiac
tumors. Even among primary
cardiac tumors, the majority (approximately 75%) are benign
and most frequently are atrial myxomas.
There are several subtypes of cardiac sarcoma, with angiosarcoma
being the most
common in adults. Other subtypes include
rhabdomyosarcoma, malignant fibrous
histiocytoma, undifferentiated,
and fibrosarcoma.
No more than 300 cases of cardiac angiosarcoma have been reported
in the literature
worldwide. Cardiac angiosarcomas can occur
in patients of any age group but are most
commonly found in
30–50-year-old patients. There is a male-to-female
predominence of
about two to one.
The clinical features of cardiac angiosarcoma
are entirely nonspecific, and the diagnosis
may not be made
until surgery or even autopsy. Presenting complaints include
chest pain,
shortness of breath, malaise, or fever. At physical
examination, the patient may have
hypotension and tachycardia.
Cardiac auscultation may reveal diminished heart sounds or a
friction rub. More than 75% of patients have electrocardiographic
abnormalities, but again
these findings are protean and include
arrhythmias, heart block, and nonspecific ST and T
wave changes.
Cardiac tamponade from a bloody pericardial effusion may lead
to heart
failure. Apparently, this
event commonly leads to patient presentation in cases of cardiac
angiosarcoma.
Nearly 80% of cardiac angiosarcomas arise as mural masses in
the right atrium. They
may invade adjacent structures such as
the superior or inferior venae cavae or the tricuspid
valve.
Echocardiography remains the initial imaging modality of choice
for evaluating cardiac
masses. It accurately depicts cardiac
anatomy in multiple planes as well as involvement of the
tricuspid
valve. However, echocardiography has limited ability to demonstrate
tumor
infiltration and cannot depict mediastinal and extracardiac
involvement.
The most common
chest radiographic finding is cardiomegaly.
Other abnormalities include right-sided heart
enlargement, widened
mediastinum, hilar adenopathy, pulmonary congestion, or pleural
effusion.
At cross-sectional imaging studies, cardiac angiosarcomas demonstrate
two patterns
of growth. The first and more common pattern is
a well-defined mass arising from the free
Shahzad G. Raja
152
wall of the right
atrium. Often, these masses contain areas of hemorrhage
and necrosis, which
appear with a heterogeneous pattern on MR
images. Areas of high signal intensity within the
tumor
are thought to represent subacute blood products. CT usually
shows a low-attenuation
right atrial mass, which may be irregular
or nodular. Enhancement with contrast material is
typically
heterogeneous on both CT and MR images.
The second and less common pattern of
growth involves tumor
infiltration along the pericardium, in which pericardial effusion
and
thickening may be seen on CT scans.
Angiosarcoma is a tumour of endothelial and mesenchymal cells. They are usually
haemorrhagic and often have poorly defined
borders. They are aggressive tumours, often
invading contiguous
structures such as the venae cavae and tricuspid valve. The
vast majority
arise from the right atrium. Cardiac
angiosarcomas can both invade and encase the
myocardium. Characteristic
areas of vascular channels lined by pleomorphic and atypical
cells
are seen. The presence of irregular anastomosing sinusoidal
structures with papillary
intraluminal tufting is diagnostic
of these tumours. Higher mitotic rates and necrosis are
correlated
with poorer outcome. Typically, these tumors stain positive
for a variety of
immunohistochemical markers, including CD34,
CD31, factor VIII–related antigen, and
vimentin. The hallmark
of cardiac angiosarcoma at electron microscopy is Weibel-Palade
bodies, which are characteristic for endothelial cells, but
these structures are often not seen.
No conclusive strategy exists for treating cardiac soft-tissue
tumours. The mainstay of
treatment is surgical resection.
Unfortunately, patient outcome is almost invariably poor
because
of the unfavorable location of these tumours, their rapid growth,
and early metastases.
However, surgical excision can substantially
alleviate symptoms and yield a modest
improvement in survival.
The mean survival time without surgical resection is approximately
4 months, which improves to 10 months following surgery.
The role of chemotherapy and irradiation is evolving, but traditionally
angiosarcomas are
thought to be unresponsive to these treatments. Although heart transplantation has been
attempted, the
results remain disappointing.
References
Best AK, Dobson RL, Ahmad AR. Best cases from the AFIP: cardiac angiosarcoma.
Radiographics. 2003;23 Spec No:S141-5.
Vander Salm TJ. Unusual primary tumors of the heart. Semin Thorac Cardiovasc Surg.
2000;12:89-100.
2.8 Answer: D
The transoesophageal echocardiogram shows a left atrial myxoma. Myxoma constitutes
50% of all benign cardiac tumours in adults. However, it comprises only 15% of such
tumours in children. It rarely occurs during infancy. Myxomas predominantly occur
sporadically and tend to be more common in women than men.
94% of tumours are solitary
with a peak incidence between the third and sixth decades of
life. Left atrium is the usual site
of occurrence in approximately 75% of cases. The deoxyribonucleic acid (DNA) genotype
of
sporadic myxomas is normal in 80% of patients. Tumours have a low recurrence rate and are
rarely associated with other abnormal conditions.
About 5% of myxoma have a familial pattern of tumour
development with autosomal
dominant inheritance. Abnormal
DNA genotype chromosomal pattern is seen in patients with
familial myxoma and 20% of those with sporadic myxoma. Familial myxoma patients
are
Cardiac Surgery: Answers
153
more likely to be younger, equally likely to be male or
female, and more often (22%) have
multicentric tumours arising
from either the atrium or ventricle compared to the "typical"
sporadic myxoma profile of a middle-aged, frequently female
patient with a single left atrial
myxoma. Familial
myxoma has a higher recurrence rate after surgical resection
(21 to 67%)
despite similar histology as sporadic tumours. Conditions such as adrenocortical nodule
hyperplasia,
Sertoli cell tumors of the testes, pituitary tumours, multiple
myxoid breast
fibroadenomas, cutaneous myomas, and facial or
labial pigmented spots are present in
approximately 20% of familial patients. These conditions often are described
as complex
myxomas within the group of familial myxoma. Carney’s complex, a
familial syndrome with
autosomal X-linked inheritance, is characterized
by primary pigmented nodular adrenocortical
disease with hypercortisolism,
cutaneous pigmentous lentigines, and cardiac myxoma.
References
Reynen K. Cardiac myxomas. N Engl J Med. 1995;333:1610-7.
McCarthy PM, Schaff HV, Winkler HZ, et al. Deoxyribonucleic acid ploidy pattern of
cardiac myxomas. J Thorac Cardiovasc Surg. 1989; 98:1083-6.
Carney JA. Differences between nonfamilial and familial cardiac myxoma. Am J Surg Pathol.
1985;64:53-5.
2.9 Answer: E
Myxomas arise from the left atrium in approximately 75%
of cases. The next most
common site is the right atrium,
where 10 to 20% are found. The remaining 6 to 8% are
equally
divided between the left and right ventricles. Both biatrial
and multicentric tumours
are commonly associated with the familial disease.
Bidirectional growth of
a tumour
originating within the atrial septum probably gives rise to biatrial tumours. Atrial myxomas
commonly originate from the interatrial septum at the border of
the fossa ovalis but can arise
anywhere within the atrium,
including the appendage. In addition,
isolated reports confirm
that myxomas arise from the cardiac
valves, pulmonary artery and vein, and vena cava.
Compared to left atrial myxomas right
atrial tumours are more likely to have broad-based
attachments. Right atrial myxomas also are more likely to be calcified
and thus visible on
chest radiographs. Ventricular
myxomas may be multicentric and occur more often in women
and children. Left ventricular tumours tend to originate in the proximity
of the posterior
papillary muscle while right ventricular tumours typically arise from the free wall.
References
Waller BF, Grider L, Rohr TM, et al. Intracardiac thrombi: Frequency, location, etiology and,
complications: A morphologic review, part I. Clin Cardiol. 1995;18:477-9.
Burke AP, Virmani R. Cardiac myxoma: A clinicopathologic study. Am J Clin Pathol.
1993;100:671-80.
Imperio J, Summers D, Krasnow N, et al. The distribution patterns of biatrial myxoma. Ann
Thorac Surg. 1980;29:469-73.
2.10 Answer: D
Histologically, myxomas are composed of polygonalshaped cells
and capillary channels
within an acid mucopolysaccharide matrix. The cells appear singularly or in small clusters
throughout the matrix, and mitoses are rare. The matrix also
contains a smattering of smooth
Shahzad G. Raja
154
muscle cells, reticulocytes,
collagen, elastin fibers, and a few blood cells. Cyst, areas
of
hemorrhage, and foci of extramedullary haematopoiesis are
present throughout the matrix.
Ten percent of the tumours
have microscopic deposits of calcium and metastatic bone
deposits,
as well as sometimes glandular-like structures. The base
of the tumour contains a
large artery and veins that connect
with the subendocardium but do not extend deeply beyond
the
subendocardium in most cases. Myxomas tend to grow into
the overlying cardiac cavity
rather than into the surrounding
myocardium. The tumour surface is covered by a monolayer
of polygonal
cells with interspersed primitive blood vessels.
Myxomas arise from the endocardium and are considered derivative
of the
subendocardial multipotential mesenchymal cell,
although origin from endocardial nervous
tissue also has been
suggested. The multipotential mesenchymal cells are thought
to be
embryonic cells left behind during septation of the heart
and are capable of differentiating into
endothelial cells, smooth
muscle cells, angioblasts, fibroblasts, myoblasts, and cartilage.
This
accounts for the occasional presence of hematopoietic tissue
and bone in these tumours. There
is no evidence that these tumours
are of thrombotic origin, as was speculated formerly.
Interestingly, myxomas have developed after cardiac trauma,
including repair of atrial
septal defects and transseptal puncture
for paracutaneous dilatation of the mitral valve.
References
Burke AP, Virmani R. Cardiac myxoma: A clinicopathologic study. Am J Clin Pathol.
1993;100:671-80.
Lie JT. The identity and histogenesis of cardiac myxomas: A controversy put to rest. Arch
Pathol Lab Med. 1989;113:724-6.
2.11 Answer: B
The classic triad of myxoma clinical presentation is intracardiac
obstruction with
congestive heart failure (67%), signs of embolization
(29%), systemic or constitutional
symptoms of fever (19%) and
weight loss or fatigue (17%), and immunologic manifestations
of myalgia, weakness, and arthralgia (5%), with almost all patients
presenting with one or
more of these symptoms. Cardiac rhythm
disturbances and infection occur less frequently.
Obstruction of blood flow in the heart is the most
common cause of acute presenting
symptoms. The nature of these
symptoms is determined by which of the chambers is involved
and the size of the tumour.
Myxomas in the left atrium tend to mimic mitral valvular heart
disease. They produce
dyspnea, which may be positional, and
other signs and symptoms of heart failure associated
with elevated
left atrial and pulmonary venous pressures. Clinically, mitral
stenosis often is
suspected and leads to echocardiography and
diagnosis of myxoma. On occasion, large
myxomas may interfere
with mitral leaflet closure and produce mitral regurgitation,
but this is
uncommon. Syncopal episodes occur in some patients
and are thought to result from
temporary occlusion of the mitral
orifice. Right atrial myxomas can produce a clinical
picture
of right-sided heart failure with signs and symptoms
of venous hypertension, including
hepatomegaly, ascites, and
dependent oedema. The tumour simulates tricuspid valve stenosis
by partially obstructing the valve orifice. If
a patent foramen ovale is present, right-to-left
atrial shunting
may occur with central cyanosis, and paradoxical embolization
has been
reported.
Cardiac Surgery: Answers
155
Large ventricular myxomas may mimic ventricular outflow obstruction.
The left
ventricular myxoma may produce the equivalent of subaortic
or aortic valvular stenosis,
whereas right ventricular
myxomas can simulate right ventricular outflow track or pulmonic
valve obstruction.
References
Percell RL Jr, Henning RJ, Siddique Patel M. Atrial myxoma: case report and a review of the
literature. Heart Dis. 2003;5:224-30.
Rosenzweig A, Harrigan P, Popvic AD. Left ventricular myxoma simulating aortic stenosis.
Am Heart J. 1989;117:962-3.
2.12 Answer: A
Removal of atrial myxomas carries an operative mortality rate
of 5% or less. A review of
202 resections indicates that operative
mortality is related to advanced age or disability and
comorbid
conditions. Excision of ventricular myxomas carries a higher
risk (approximately
10%), but the experience is small.
Recurrence of nonfamilial sporadic myxoma is approximately 1
to 4%. It probably is
even lower in patients with a
normal DNA genotype. Many large series report no recurrent
tumours.
The 20% of patients with sporadic myxoma and abnormal DNA have
a recurrence
rate estimated at between 12% and 40%. The
recurrence rate is highest in patients with
familial complex
myxomas, all of whom exhibit DNA mutation, and this is estimated
to be
about 22%. Overall, recurrences are more common in younger
patients. The disease-free
interval averages about 4 years and
can be as brief as 6 months. Most recurrent myxomas
occur
within the heart, in the same or different cardiac chambers,
and may be multiple. The
relationship of local
recurrence to the adequacy of the original resection remains
unsettled
because sporadic tumours rarely recur even if full-thickness
excision of the base is not done
and because recurrent tumours
often do not recur at the site of the original tumor.
Extracardiac
recurrence after resection of tumour, presumably
from embolization and subsequent tumour
growth and local invasion,
has been observed. The biology of the tumour,
dictated by gene
expression rather than histology, may be the
only reliable factor predicting recurrence. DNA
testing of all
patients with cardiac myxoma may prove to be the best predictor
of the
likelihood of recurrence.
References
Percell RL Jr, Henning RJ, Siddique Patel M. Atrial myxoma: case report and a review of the
literature. Heart Dis. 2003;5:224-30.
McCarthy PM, Piehler JM, Schaff HV, et al. The significance of multiple, recurrent, and
"complex" cardiac myxoma. J Thorac Cardiovasc Surg. 1986;91:389-96.
Actis Dato GM, De Benedictis M, Actis Dato A Jr, et al. Long-term follow-up of cardiac
myxomas (7–31 years). J Cardiovasc Surg. 1993;34:141-3.
2.13 Answer: E
Lipomas are well-encapsulated tumours consisting of mature fat
cells. These may occur
anywhere in the heart as well as in the pericardium, subendocardium, subepicardium, and
intra-atrial
septum. They have no age or sex predilection.
Lipomas are slow growing tumours.
They may acquire considerable size before
producing obstructive or arrhythmic symptoms.
Shahzad G. Raja
156
Majority produce no symptoms
and are discovered incidentally on routine chest radiographs,
echocardiogram, or at surgery or autopsy. Subepicardial
and parietal lipomas cause cardiac
compression and may be associated
with pericardial effusion. Chamber obstruction may be
produced by subendocardial tumours. The right atrium and left ventricle are
the most
commonly involved sites. Arrhythmias or conduction abnormalities can be produced by
lipomas lying within the myocardium
or septum.
Surgical resection is indicated for large
tumours that produce severe symptoms.
Smaller, asymptomatic tumours confronted
unexpectedly during
cardiac surgery should be resected if excision can be performed
without
adding risk to the primary procedure. These tumours are
not known to recur.
References
Miyai N, Kawasaki T, Taniguchi T, et al. Cardiac lipoma. Intern Med. 2005;44:905-6.
Sirinivas BK, Gopalakrishnan M, Mahadevan R, et al. Lipoma of the left ventricle. Asian
Cardiovasc Thorac Ann. 2002;10:64-5.
Kusano KF, Ohe T. Cardiac tumors that cause arrhythmias. Card Electrophysiol Rev.
2002;6:174-7.
2.14 Answer: A
Rhabdomyoma is the most common cardiac tumour in
children and usually presents
during the first few days after
birth. It is regarded as a myocardial hamartoma rather than
a
true neoplasm. Rhabdomyoma appears sporadically as well as has a strong association with
tuberous sclerosis. Tuberous sclerosis is a hereditary
disorder characterized by hamartomas in
various organs, epilepsy,
mental deficiency, and sebaceous adenomas. Fifty percent of
patients with tuberous sclerosis have rhabdomyoma while more
than 50% of patients with
rhabdomyoma have or will develop tuberous
sclerosis. The exceptional patient is one with a
solitary rhabdomyoma who does not have or develop tuberous sclerosis.
Rhabdomyomas occur with approximately
equal frequency in both ventricles and over
90% are multiple. The atrium is involved
in less than 30% of patients. On gross examination,
these tumours
are firm, gray, and nodular and tend to project into the ventricular
cavity.
Histologically, they are composed of myocytes of twice normal size filled
with glycogen and
containing hyperchromatic nuclei and eosinophilic-staining
cytoplasmic granules. Electron
microscopy shows scattered bundles of myofibrils within cells.
Rhabdomyoma most commonly presents as heart failure due to tumour
obstruction of
cardiac chambers or valvular orifice flow. Clinical
findings are similar to those of valvular or
subvalvular stenosis. Arrhythmias,
particularly ventricular tachycardia and sudden death, may
be
a presenting symptom. Atrial tumours may produce atrial arrhythmias.
The diagnosis is
suggested by clinical features of tuberous
sclerosis and is confirmed by echocardiography.
Rarely, electrophysiologic study may be required to locate the site of rhabdomyoma if no
intramyocardial
tumour is found in a patient with ventricular arrhythmias.
Early operation is recommended in patients who do not have tuberous
sclerosis before 1
year of age. The tumour usually is excised
easily in early infancy, and some can be
enucleated. Unfortunately,
symptomatic tumours often are both multiple and extensive with
dismal long-term prognosis. In such cases, surgery offers
little benefit.
This is particularly
true
for patients with tuberous sclerosis.
Cardiac Surgery: Answers
157
References
Burke A, Virmani R. Pediatric heart tumors. Cardiovasc Pathol. 2008;17:193-8.
Uzun O, Wilson DG, Vujanic GM,et al. Cardiac tumours in children. Orphanet J Rare Dis.
2007;2:11.
2.15 Answer: D
Approximately 10% of metastatic tumours involve the
heart or pericardium, and almost
every type of malignant tumour
has been known to metastasize to these structures. Secondary
tumours are 20
to 40 times more common than primary cardiac neoplasms.
Up to 50% of
patients with leukemia have cardiac involvement.
Other cancers that commonly metastasize to
the heart include breast
and lung cancers, lymphoma, melanoma, and various sarcomas.
Metastases involving the pericardium, epicardium, myocardium,
and endocardium roughly
follow that order of frequency as
well.
Tumours such as melanoma,
sarcoma, and bronchogenic carcinoma spread to the heart by
haematogenous route. Other routes of spread to the heart include lymphatic channels as well
as through direct extension from
adjacent lung, breast, oesophageal, and thymic tumours. In
addition, metastases can involve the heart from
the subdiaphragmatic vena cava. Generally,
the heart
is the target of haematologous and/or retrograde lymphatic metastasis whereas the
pericardium is involved
most often by direct extension of thoracic cancer.
Cardiac metastases
nearly always produce
multiple microscopic nests and discrete nodules of tumour cells. They
are rarely solitary. Only about 10% of patients with cardiac metastases experience clinical
symptoms. The most common
symptom is pericardial effusion or cardiac tamponade.
Occasionally, refractory arrhythmias or congestive heart
failure develop. Chest radiographs
and electrocardiograms tend to show
nonspecific changes. Echocardiography is particularly
beneficial
for identifying pericardial effusion, irregular pericardial
thickening, or intracavity
masses interfering with blood flow.
As these patients have widespread disease with limited life expectancies therefore
surgical therapy is directed at providing symptomatic palliation
with minimal patient
discomfort and hospital stay. Surgical treatment has a limited role usually for providing relief
of recurrent pericardial
effusions or, occasionally, cardiac tamponade. This is most
effectively
achieved via subxiphoid pericardiotomy. Subxiphoid pericardiotomy can
be performed under
local anaesthesia if necessary with reliable
relief of symptoms. It is associated with negligible
mortality and a recurrence rate of about 3%. Other option is thoracoscopic creation of a large
pericardial window in the
left pleural space. However, it is recommended only under unusual
circumstances. This
can be accomplished with minimal patient discomfort but may be poorly
tolerated by patients with hemodynamic deterioration
secondary to large effusions as it
requires general anaesthesia with single-lung ventilation.
References
Al-Mamgani A, Baartman L, Baaijens M, et al. Cardiac metastases. Int J Clin Oncol.
2008;13:369-72.
O'Sullivan PJ, Gladish GW. Cardiac tumors. Semin Roentgenol. 2008;43:223-33.
Shahzad G. Raja
158
2.16 Answer: D
In the 2008 focused update incorporated into the ACC/AHA 2006 guidelines for the
management of patients with valvular heart disease recommendations for aortic valve
selection are as follows:
Class I
1. A mechanical prosthesis is recommended for AVR in patients with
a mechanical valve
in the mitral or tricuspid position. (Level
of Evidence: C)
2. A bioprosthesis is recommended for AVR in
patients of any age
who will not take
warfarin or who have major
medical contraindications
to warfarin therapy. (Level of
Evidence:
C)
Class IIa
1. Patient preference is a reasonable consideration in the selection
of aortic valve
operation and valve prosthesis. A mechanical
prosthesis is reasonable for AVR in patients
under 65 years
of age who do not have a contraindication to anticoagulation.
2. A
bioprosthesis is reasonable for AVR in patients under 65 years
of age who elect to receive this
valve for lifestyle considerations
after detailed discussions of the risks of anticoagulation
versus
the likelihood that a second AVR may be necessary in the future.
(Level of Evidence:
C)
3. A bioprosthesis is reasonable for AVR
in patients aged 65 years
or older without risk
factors for
thromboembolism. (Level of
Evidence: C)
4. Aortic valve re-replacement
with a homograft is reasonable for
patients with active
prosthetic
valve endocarditis. (Level of
Evidence: C)
Class IIb
1. A bioprosthesis might be considered for AVR in a woman of
childbearing age. (Level
of Evidence:
C)
References
Bonow RO, Carabello BA, Chatterjee K, et al. 2008 Focused update incorporated into the
ACC/AHA 2006 guidelines for the management of patients with valvular heart disease: a
report of the American College of Cardiology/American Heart Association Task Force on
Practice Guidelines (Writing Committee to Revise the 1998 Guidelines for the
Management of Patients With Valvular Heart Disease): endorsed by the Society of
Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and
Interventions, and Society of Thoracic Surgeons. Circulation. 2008;118:e523-661.
Lytle BW, Cosgrove DM, Taylor PC, et al. Primary isolated aortic valve replacement: early
and late results. J Thorac Cardiovasc Surg. 1989; 97: 675-94.
2.17 Answer: D
Holosystolic (pansystolic) murmurs are generated when there
is flow between chambers
that have widely different pressures
throughout systole, such as the left ventricle and either
the
left atrium or right ventricle. With an abnormal regurgitant
orifice, the pressure gradient
and regurgitant jet begin early
in contraction and last until relaxation is almost complete.