Ann Thorac Surg 2005;79:2141-2143
© 2005 The Society of Thoracic Surgeons
Case report
Localized Pericardial Hematoma Presenting With Acute Hypoxemia
Paul C. Saunders, MDa,
Juan B. Grau, MDa,*,
Carol L. Chen, MDb,
Michael Zervos, MDa,
Charles F. Schwartz, MDa,
Stephen B. Colvin, MDa,
Barry P. Rosenzweig, MDb,
Greg H. Ribakove, MDa
a Division of Cardiothoracic Surgery, Department of Surgery, New York University School of Medicine, New York, New York, USA
b Division of Cardiology, Department of Medicine, New York University School of Medicine, New York, New York
Accepted for publication November 25, 2003.
* Address reprint requests to Dr Grau, New York University School of Medicine, 530 First Ave, Suite 9V, New York, NY10016 (E-mail: grau{at}cv.med.nyu.edu).
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Abstract
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Localized pericardial hematomas after cardiac surgery may have atypical clinical presentations due to regional alterations in cardiac function and hemodynamics. We report a case of extravascular thrombus that compressed the main pulmonary artery and produced acute hypoxemia due to right-to-left shunting across a patent foramen ovale. We review the pathophysiology leading to this finding and the echocardiographic studies that established the diagnosis.
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Introduction
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Successful management of acute decompensation after cardiac surgery requires synthesis of clinical, laboratory, and imaging data. One of the most lethal postoperative complications, cardiac tamponade, classically presents with pulsus paradoxus, elevated central venous pressure, and hypotension, along with echocardiographic evidence of compression of right heart structures [1, 2]. However, if cardiac compression is due to a localized pericardial hematoma, the presentation may be atypical, due to the pattern of compression of various cardiac structures [1].
We recently observed a case in which an extravascular thrombus compressing the main pulmonary artery produced marked hypoxemia and hemodynamic collapse after coronary artery bypass grafting. Both transthoracic and transesophageal echocardiography was instrumental in making the diagnosis to understand the complex pathophysiology involved.
A 57-year-old woman who had presented with unstable angina underwent coronary revascularization with saphenous vein grafting of the left anterior descending and obtuse marginal coronary arteries. The intraoperative course was uncomplicated, and she was successfully extubated 8 hours after surgery.
Approximately 16 hours after surgery, the patient became acutely hypoxic with an oxygen saturation of 85%, hypoxemic with a PaO2 of 54 mm Hg on room air, and hypotensive requiring intravenous pressor support. Her heart sounds were normal and an elevated pulsus paradoxus was absent. A Swan-Ganz catheter revealed a right ventricular pressure of 54/6 mm Hg, but it would not advance into the pulmonary artery.
An emergent transthoracic echocardiogram revealed several new findings in comparison with the preoperative study. Although the left ventricular function remained normal, a small pericardial effusion was noted, but there was no evidence of cardiac compression. A high velocity flow of 3.3 m/s was detected by continuous wave Doppler interrogation in the region of the right ventricular outflow tract, the pulmonic valve, and the proximal pulmonary artery. The pulmonic valve could not be imaged. An augmented a-wave was apparent in the Doppler envelope, consistent with elevated right atrial and ventricular diastolic pressures. Severe tricuspid regurgitation with a peak velocity of 3.5 m/s was now present as well. On apical views, bowing of the interventricular septum into the left heart and prominence of the coronary sinus were seen, also consistent with elevated right-sided pressures.
A transesophageal echocardiogram demonstrated compression of the main pulmonary artery by an echo-dense mass several centimeters in diameter (Fig 1). Accelerated flow just distal to the pulmonic valve was consistent with flow obstruction at the level of the mass. The interatrial septum was highly mobile, and color flow Doppler demonstrated a patent foramen ovale with a wide jet of right-to-left shunt across it (Fig 2).
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Fig 1. Transesophageal echocardiogram (50° view) showing obstruction of the pulmonary artery by a solid mass (arrows). (A = aorta; LA = left atrium; PA = pulmonary artery; RV = right ventricle.)
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Fig 2. Transesophageal echocardiogram (40° view) showing a patent foramen ovale with a right-to-left shunt. Note the septum primum (solid arrow), the septum secundum (dotted arrow), and the color flow demonstrating the shunt from the right atrium (red) to the left atrium (mosaic color). (LA = left atrium; RA = right atrium.)
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The patient was returned to the operating room for urgent reexploration. Although there was no significant pericardial effusion, a clot (2 cm x 2 cm) was found compressing the proximal pulmonary artery and the pulmonic valve. A small adventitial tear was identified in the graft to the marginal coronary artery, and it was repaired.
The Swan-Ganz catheter was now easily advanced into the pulmonary artery, demonstrating normal right ventricular and pulmonary artery pressures and a normal cardiac index. With relief of the cardiac compression, the patient’s oxygen saturation returned to 100%, and she was quickly weaned from ventilatory and pressor support. She made an uneventful recovery and was discharged home on postoperative day 4.
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Comment
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Extrinsic compression of cardiac structures after cardiac surgery frequently results in hemodynamic collapse. When compression is produced by localized hematomas, typical symptoms and hemodynamics consistent with the structure affected may be encountered [1]. In a retrospective series of 29 patients with postoperative cardiac tamponade, two-thirds of the patients had a localized posterior pericardial hematoma, and of these, only 16% had hypotension and only 47% had an abnormal pulsus paradoxus [3]. Although transthoracic echo may be more readily available and more expeditious in the postoperative setting, several reports have noted the superiority of transesophageal echocardiography versus transthoracic echocardiography in identifying localized hematomas [2, 4, 5]. In this case, the transthoracic echocardiogram revealed evidence of elevated right-sided pressures, but it did not show the hematoma that was clearly demonstrated by transesophageal echocardiography.
The presentation of acute hypoxemia, as in this patient, is not classically associated with cardiac tamponade, which would suggest alternative diagnoses. In addition, the presence of an interatrial connection with a right-to-left shunt complicated the diagnosis, because it did not produce an elevated pulsus paradoxus [6]. Intracardiac right-to-left shunting has not been frequently described after cardiac surgery [7], although Adolph and colleagues [8] reported a case of reversible right-to-left shunting and hypoxemia produced by a pericardial effusion 2 weeks after coronary artery bypass grafting. In that report, the patient’s symptoms resolved with conservative management.
Factors that may play a role in the opening of a patent foramen ovale include positive pressure ventilation, positive end-expiratory pressure support, changes in right ventricular compliance due to prolonged cardioplegic arrest, and altered right atrial geometry, which causes atrial septal distortion [7]. In this case, obstruction of the right ventricular outflow tract resulted in acute right ventricular and right atrial hypertension and caused the paradoxical atrial shunt with hypoxemia. Echocardiogram confirmed that the right-to-left shunt had disappeared once the compression of the right ventricular outflow tract had been relieved.
This case demonstrates an atypical presentation of hemodynamic instability after cardiac surgery and further highlights the value of transesophageal echocardiography in this setting. It also underscores the degree to which a relatively common and usually benign finding, a patent foramen ovale, can complicate the clinical evaluation of the postoperative patient.
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References
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- Russo AM, O’Connor WH, Waxman HL. Atypical presentations and echocardiographic findings in patients with cardiac tamponade occurring early and late after cardiac surgery Chest 1993;104:71-78.[Abstract/Free Full Text]
- Kochar GS, Jacobs LE, Kotler MN. Right atrial compression in postoperative cardiac patientsdetection by transesophageal echocardiography. J Am Coll Cardiol 1990;16:511-516.[Abstract]
- Chuttani K, Tischler MD, Pandian NG, et al. Diagnosis of cardiac tamponade after cardiac surgeryrelative value of clinical, echocardiographic, and hemodynamic signs. Am Heart J 1994;127:913-918.[Medline]
- Saner HE, Olson JD, Goldenberg IF, et al. Isolated right atrial tamponade after open heart surgeryrole of echocardiography in diagnosis and management. Cardiology 1995;86:464-472.[Medline]
- Ionescu A, Wilde P, Karsch KR. Localized pericardial tamponadedifficult echocardiographic diagnosis of a rare complication after cardiac surgery. J Am Soc Echocardiogr 2001;14:1220-1223.[Medline]
- Winer HE, Kronzon I. Absence of paradoxical pulse in patients with cardiac tamponade and atrial septal defects Am J Cardiol 1979;44:378-380.[Medline]
- Schoevaerdts D, Gonzalez M, Evrard P, et al. Patent foramen ovalea cause of significant post-coronary artery bypass grafting morbidity. Cardiovasc Surg 2002;10:615-617.[Medline]
- Adolph EA, Lacy WO, Hermoni YI, et al. Reversible orthodeoxia and platypnea due to right-to-left intracardiac shunting related to pericardial effusion Ann Intern Med 1992;116:138-139.
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Abstract
Introduction
