Ann Thorac Surg 2005;80:324-326
© 2005 The Society of Thoracic Surgeons
Case report
Pulmonary and Paradoxical Embolism in Protein C and S Deficient Patient
Sanjay Kumar, MCh, FRCS,
Irfan Khan, MRCS,
Richard Milton, FRCS,
Ayyaz A. Ali, MRCS,
David J. O’Regan, MD, FRCS C-Th*
Department of Cardiothoracic Surgery, Yorkshire Heart Centre, Leeds General Infirmary, Leeds, United Kingdom
Accepted for publication December 29, 2003.
* Address reprint requests to Dr Takano, Department of Surgery E-1, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan (Email: sanjaykr33{at}hotmail.com).
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Abstract
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We document the case of a 67-year-old woman who presented with a history of right upper quadrant anopia, dyspnea, hypoxemia, and a systolic murmur. An intracardiac embolus wedged at a patent foramen ovale was successfully removed by resecting the atrial septum along with a pulmonary embolectomy on cardiopulmonary bypass. We review the literature with specific focus on the pathogenesis and acute treatment options of this life-threatening occurrence.
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Introduction
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The paradoxical embolism is an uncommonly diagnosed but potentially catastrophic phenomenon. According to d’Audiffret and colleagues [1], Meister’s [2] clinical criteria for the elements of diagnosis include the presence of a venous thrombus, an arterial embolus, a communication between the right and left heart, and a transient reversal of the intracardiac shunts. According to Ward and colleagues [3], Johnson [4] categorized paradoxical embolism as "presumptive" in the presence of the first three findings and "proved" thrombus is lodged between an intracardiac septal defect at autopsy. Unfortunately all of these criteria can rarely be demonstrated in each case.
We believe that our patient is the first reported case of a "thrombus-in-transit" across the interatrial septum in a protein C and S deficient patient with a patent foramen ovale (PFO), a deep venous thrombosis, and an embolic cerebrovascular event.
A 67-year-old woman presented with a sudden onset of left sided retro-orbital headache associated with blurred vision in her left eye. Her past medical history indicated hypertension and asthma. Examination revealed a right upper quadrant anopia. She was in sinus rhythm with a heart rate of 95 per minute and blood pressure of 150/94 mm of Hg. Her jugular venous pressure was normal. The precordial auscultation revealed a systolic murmur. An electrocardiogram showed extensive T wave inversion in leads II, III, and V1 to V4. The arterial blood gas analysis showed her to be hypoxic with a partial pressure of oxygen (PaO2) of 6.9 kPa and a mild respiratory alkalosis. With further specific enquiry, the patient volunteered a 2-week history of breathlessness and feeling a right-sided pleuritic pain 3 days previously.
A ventilation-perfusion scan confirmed the presence of a pulmonary embolus. She was subsequently initiated on subcutaneous low molecular weight heparin. A computed tomographic scan of her head revealed a left occipital hemispheric attenuation consistent with an embolic event (Fig 1a). A transthoracic echocardiogram was performed, which raised the suspicion of a mobile mass in the normal sized left atrium with mild tricuspid regurgitation and good left ventricular systolic function (ejection fraction, >60%). This was followed by a transesophageal echocardiogram, which confirmed the presence of a large mobile thrombus straddling a PFO (Fig 1b). A lower limb duplex scan demonstrated thrombus within the left popliteal vein.
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Fig 1. (a) Contrast enhanced computed tomographic scan of the head shows left occipital infarct. (b) Transesophageal echocardiogram shows a thrombus (outlined in dotted lines) wedged in the patent foramen ovale, in the right atrium (RA), and in the left atrium (LA). (A = aortic valve.) (c) Contrast- enhanced computed tomographic scan of the chest shows a large volume of thrombus within both main pulmonary arteries and (d) shows the excised vermiform thrombus that was wedged in the patent foramen ovale.
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The patient was referred for cardiac embolectomy and closure of a PFO to preempt further systemic embolization. A computed tomographic scan of her thorax depicted extensive thrombus in both pulmonary artery beds (Fig 1c). Based on the information from these investigations it was decided to proceed to surgery with a further transesophageal echocardiogram (on table) to confirm embolus still in situ after transportation. A preoperative angiogram showed mild coronary artery disease and no thrombus.
The procedure was performed through a median sternotomy. Cardiopulmonary bypass was established with aorto-bicaval cannulation. The heart was arrested with antegrade cold blood cardioplegia. The right atrium was opened and the atrial septum, including the PFO, was resected to remove the vermiform thrombus that was found to be wedged in the PFO (Fig 1d). The septum was reconstructed with bovine pericardium. The left atrial appendage was ligated. After cross-clamp removal, the air was thoroughly removed from the left heart. The pulmonary artery was opened between stays, and an embolectomy was performed. Eight grams of thrombus was removed. The cardiopulmonary bypass was discontinued easily with a background infusion of dopamine. The cardiopulmonary bypass and total cross-clamp time was 60 and 30 minutes, respectively. The patient was transferred to intensive care and was extubated after 4 hours according to our intensive care guidelines. She was alert and orientated with no focal neurologic deficits. She was anti-coagulated with coumarin with a target international normalized ratio of 2.5 according to the British Committee for Standards in Hematology guidelines. Her preoperative investigations revealed a protein C level of 38.4 (normal reference range, 70 to 120) and a protein S level of 26.8 (normal reference range, 70 to 130). She was discharged on postoperative day 6, having made an uneventful recovery. At her 6-month outpatient follow-up she was asymptomatic and in New York Heart Association’s functional class I.
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Comment
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The foramen ovale remains patent through adulthood in approximately as much as 35% of the general population [1]. A PFO permits interatrial right-to-left shunting during those periods of time when the right atrial pressure exceeds the left atrial pressure. A PFO accounts for 70% of all right-to-left cardiac shunts [3, 5]. This is associated with a 16% incidence of a paradoxical embolism or higher, particularly when associated with an atrial septal aneurysm [6]. Paradoxical embolism was first described by Julius Friedrich Cohnheim, experimental pathologist, in 1877 according to Ward and colleagues [3]. A paradoxical embolism through a PFO can simultaneously involve multiple organs. The most commonly involved sites are the cerebrum and lower extremities, whereas paradoxical embolism to coronary arteries or upper extremities is relatively uncommon. A PFO was found in 45% of those with cryptogenic stroke [6]. The incidence of deep venous thrombosis (apparent on phlebography) in a population with a PFO and stroke is 57% [3, 6]. The source of the clot cannot be established in most cases.
In our patient, we presume that high right atrial pressure resulting from pulmonary embolism led to the reversal of normal intraatrial pressure resulting in a right-to-left shunt through a PFO, allowing a venous thromboembolic access to the arterial circulation and posterior cerebral territory.
The transesophageal echocardiogram remains the preferred investigation test as it offers examination of the atria, the interatrial septum, and morphologic detail of the embolus, especially in the intubated and ventilated patients. A transesophageal echocardiogram should always be repeated just before surgery to confirm the presence of a clot and indication for surgery [6]. A coronary angiogram is essential in elderly patients to exclude coronary artery disease and any paradoxical coronary embolism, especially in patients with electrocardiographic changes [5, 6].
The repair of a PFO is reported as the optimal treatment to prevent recurrent stroke [7]. Similarly, careful inspection of the right atrium for the presence and closure of a PFO is necessary during the surgical intervention for a chronic pulmonary thromboembolism [5]. In this case, the septum had to be resected as the paradoxical embolism was wedged and risked further disruption. Percutaneous transcatheter closure of a PFO is also used as an alternative to surgery, but with a residual shunt rate of 27% [5, 8, 9].
Hypercoagulable states, such as protein C or S deficiency should be considered in those patients who develop venous thromboembolism in the absence of known risk factors. The use of continuous anticoagulant prophylaxis is not warranted in asymptomatic individuals with a deficiency of antithrombin or protein C or S, because the annual incidence of deep venous thrombosis is only 1.5% [10]. A coagulation or hematological disorder is observed in less than 5% of PFO-associated strokes [10].
We conclude that paradoxical embolism should be in the differential diagnoses of patients presenting with an ischemic cerebrovascular event. Extensive investigations to rule out intracardiac abnormalities, deep venous thrombosis, causes of right to left shunting and thrombophilia should be considered. Surgery remains the most appropriate therapeutic option in the acute setting with negligible mortality and morbidity.
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Acknowledgments
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We thank Stuart Powell and Ezenee Kolbaba, Department of Medical Illustration, LGI, Leeds Teaching Hospitals, for their help with the illustration.
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References
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- d’Audiffret A, Pillai L, Dryjski M. Paradoxical embolithe relationship between patent foramen ovale, deep vein thrombosis and ischaemic stroke. Eur J Vasc Endovasc Surg 1999;17(6):468-471.[Medline]
- Meister SG, Grossman W, Dexter L, Dalen JE. Paradoxical embolismdiagnosis during life. Am J Med 1972(53):292-298.
- Ward R, Jones D, Haponik EF. Paradoxical embolisman underrecognized problem. Chest 1995;108(2):549-558.[Abstract/Free Full Text]
- Johnson BJ. Paradoxical embolism J Clin Pathol 1951(4):316-332.
- Meier B, Lock JE. Contemporary management of patent foramen ovale Circulation 2003;107(1):5-9.[Free Full Text]
- Lamy C, Giannesini C, Zuber M, et al. Clinical and imaging findings in cryptogenic stroke patients with and without patent foramen ovalethe PFO-ASA Study. Stroke 2002;33:706-711.[Abstract/Free Full Text]
- Dearani JA, Ugurlu BS, Danielson GK, et al. Surgical patent foramen ovale closure for prevention of paradoxical embolism-related cerebrovascular ischemic events Circulation 1999;100(Suppl II):II-171-II-175.
- Berdat PA, Chatterjee T, Pfammatter JP, et al. Surgical management of complications after transcatheter closure of an atrial septal defect or patent foramen ovale J Thorac Cardiovasc Surg 2000;120(6):1034-1039.[Abstract/Free Full Text]
- Windecker S, Wahl A, Chatterjee T, et al. Percutaneous closure of patent foramen ovale in patients with paradoxical embolismlong-term risk of recurrent thromboembolic events. Circulation 2000;101:893-898.[Abstract/Free Full Text]
- Sanson BJ, Simioni P, Tormene D, et al. The incidence of venous thromboembolism in asymptomatic carriers of a deficiency of antithrombin, protein C, or protein Sa prospective cohort study. Blood 1999;94(11):3702-3706.[Abstract/Free Full Text]
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Abstract
Introduction
