Embolus Entrapped in Patent
Foramen Ovale: Impending
Paradoxical Embolism
Helena Podrouzkov
a, MD, PhD,
Vladimír Horv
ath, MD, PhD, Ota Hlinomaz, MD, PhD,
Jan Bedan, MS, Miroslav Bambuch, MD, PhD,
Petr N
emec, MD, PhD, and Marek Orban, MD
International Clinical Research Center, Brno; Center of
Cardiovascular Surgery and Organ Transplantation, Brno; VUT
Brno, Brno; Tomas Bata Regional Hospital, Zlin, Czech Republic
An impending paradoxical embolism is a rare finding,
with fewer than 200 cases being documented so far. A
68-year-old woman, who presented with 3 weeks of
increasing exertional dyspnea and exercise intolerance,
underwent transesophageal echocardiography with a
finding of an embolus in both right and left atria. At an
emergent cardiac surgery, a worm-shaped, 5-cm-long
thrombus was found in the right atrium, it was protruding to left atrium through the foramen ovale. The
thrombus was removed intact, and the foramen ovale was
closed. By our experience, an emergent cardiac surgery
should always be considered as a treatment option for
impending paradoxical embolism.
(Ann Thorac Surg 2014;98:e151–2)
Ó 2014 by The Society of Thoracic Surgeons
P
aradoxical embolization defined as passage of
thrombotic masses through intracardiac or other
shunts. It is usually a dangerous clinical situation associated with symptoms of systemic and pulmonary embolism. Relatively rarely, a moment when migrating
thrombus entrapped in the shunt (typically patent
foramen ovale) is seen and recorded during clinical examinations (including three-dimensional [3D] transesophageal echocardiography [TEE]) and consequently
removed intact from cardiac chambers as it was in the
presented case.
Fig 1. Transesophageal two-dimensional echocardiography in high
esophageal position (horizontal plane) showing a large thrombus
(arrow) entrapped in patent foramen ovale. (LA ¼ left atrium;
RA ¼ right atrium.)
pressure in the pulmonary artery of 50 mm Hg. There was
no regional wall motion abnormality in the left ventricle.
Because of echo-dense structure in the right atrium,
intracardiac thrombus was suggested and a TEE examination was recommended. TEE including 3D imaging
revealed an embolus in the right and left atria, entrapped
in patent foramen ovale (PFO; Fig 1). 3D transesophageal
echocardiography confirmed the finding of impending
paradoxical embolism in a relatively large PFO (Fig 2).
Massive pulmonary embolism was shown by computed
tomography, and emergent surgery was indicated. The
results of a neurologic examination before surgery were
negative with no signs of cerebral embolism. At an
emergent cardiac surgery, a worm-shaped, 5-cm-long
thrombus was found in the right atrium. It was attached
to the interatrial septum, and it protruded to left atrium
through foramen ovale. The thrombus was removed
intact, and the foramen ovale was closed (Fig 3). Several
thrombi were also removed from the left and right main
branches of pulmonary artery. Two weeks after the
An obese 68-year-old white woman presented with 3
weeks of increasing exertional dyspnea and exercise
intolerance. Her cardiovascular history was unremarkable except for well-controlled hypertension. Two months
before admission, the patient underwent umbilical hernia
resection. In addition, the patient received a diagnosis
and treatment for breast cancer 1 year before admission.
On admission, the vital signs were normal, and the
patient suffered no resting dyspnea. The physical examination revealed only minor varices in both lower
extremities. TEE showed dilatation of the right ventricle
with moderate tricuspid regurgitation and signs of moderate pulmonary hypertension, with an estimated systolic
Accepted for publication Aug 29, 2014.
Address correspondence to Dr Orban, Center of Cardiovascular Surgery
and Organ Transplantation, Pekarska 53, 65691 Brno, Czech Republic; email: maor@post.cz.
Ó 2014 by The Society of Thoracic Surgeons
Published by Elsevier
Fig 2. Three-dimensional echocardiographic image of the entrapped
thrombus.
0003-4975/$36.00
http://dx.doi.org/10.1016/j.athoracsur.2014.08.072
e152
ET AL
CASE REPORT
PODROUZKOV
A
IMPENDING PARADOXICAL EMBOLISM
Fig 3. Intraoperative image of intact wormlike thrombus removed
from the patent foramen ovale.
operation, the patient was discharged with oral vitamin K
antagonist therapy. At 6-month’s follow-up, the patient
was doing fine and had no complaints except for mild
exertional dyspnea. Paradoxical embolism is defined by a
transit of thrombi from the venous system into the systemic circulation. Typically, paradoxical embolism is
associated with several underlying conditions. First,
venous thrombosis usually presents with at least one
thrombotic risk factor, such as hypercoagulable state,
postoperative status, malignancy, or long-term bed rest.
Second, the inevitable condition for paradoxical embolism is a communication between venous and systemic
circulation. Most frequently, it is PFO or atrial septal
defect. The third condition is a right-to-left pressure
gradient, typically in the massive pulmonary embolism or
intermittently during the Valsalva maneuver, allowing
the thrombus to migrate from right to the left atrium.
Paradoxical embolism presents as a coincidence of
venous thrombosis with pulmonary embolism and systemic embolism. The most common manifestation of
systemic embolism is a cerebrovascular event, such as
stroke or transient ischemic attack. Other possible presentations of systemic embolism are peripheral vascular
ischemia of embolic origin, acute myocardial infarction,
and renal or abdominal ischemia. When the thrombus is
large and the orifice of the venous to arterial shunt is
Ann Thorac Surg
2014;98:e151–2
relatively small, the thrombus becomes stuck in the
aperture and threatens with systemic embolism. This
state is referred to as impending paradoxical embolism.
Impending paradoxical embolism is a rare finding, with
fewer than 200 cases being documented. It is also an
extremely dangerous clinical setting, with an estimated
mortality of 18% at 30 days. At the time of diagnosis, the
systemic embolism is already present in 25% of cases [1].
Besides cerebral embolism, cases of coronary embolism
[2], embolism into abdominal aorta and its branches
[3, 4], or embolism into peripheral arteries of limbs [4]
have been documented. The main cause of death in
impending paradoxical embolism is cardiogenic shock
with right heart failure owing to massive pulmonary
embolism or a stroke [1]. Treatment options for
impending paradoxical embolism include anticoagulation, thrombolysis, and surgery. According to an
analysis of 174 cases with impending paradoxical embolism, surgical thrombectomy showed a nonsignificant
trend toward improved survival and significantly reduced
systemic embolism compared with anticoagulation alone.
Thrombolysis and anticoagulation showed an increased
prevalence of embolism after treatment initiation
compared with surgery [1]. By our experience, an emergent cardiac surgery should always be considered as a
treatment option.
This study was supported by the European Regional Development Fund, Project FNUSA-ICRC (No. CZ.1.05/1.1.00/02.0123).
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