Ann Thorac Surg 2007;84:2086-2088. doi:10.1016/j.athoracsur.2007.07.008
© 2007 The Society of Thoracic Surgeons
Case Reports
Unilateral Pulmonary Edema After Pulmonary Embolism in a Bilateral Lung Transplant Patient
Rachid Zegdi, MD, PhDa,b,*,
Nicolas Dürrleman, MDa,b,
Paul Achouh, MDa,b,
Véronique Boussaud, MDa,
Romain Guillemain, MDa,
Catherine Amrein, MDa,
Alain Deloche, MDa,b,
Jean-Noël Fabiani, MDa,b
a Assistance-Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Department of Cardiovascular Surgery, Paris, France
b René Descartes University, Paris, France
Accepted for publication July 5, 2007.
* Address correspondence to Dr Zegdi, Hôpital Européen Georges Pompidou, Service de Chirurgie Cardiovasculaire, 20, rue Leblanc, Paris, 75908, France (Email: rzegdi{at}hotmail.com).
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Abstract
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We report a case of unilateral pulmonary edema due to the decompensation of an asymptomatic ipsilateral pulmonary venous stenosis by a contralateral pulmonary embolism. Emergency surgery included pulmonary embolectomy and refashioning of the stenotic pulmonary venous anastomosis.
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Introduction
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Occurrence of pulmonary embolism after lung transplantation is underestimated [1]. Only one case of surgical pulmonary embolectomy has been reported in this context so far [2]. We report a case of severe pulmonary embolism with an atypical clinical presentation that required an emergency operation.
A 15-year-old girl underwent double-lung transplantation for end-stage cystic fibrosis. The procedure was sequentially performed through a bilateral anterolateral thoracotomy with a femorofemoral extracorporeal circulation. Ischemic times were 4 hours for the right lung and 5 hours for the left lung. Mild graft dysfunction was present on postoperative chest roentgenogram, but weaning from ventilation was possible on postoperative day 1. Postoperative thromboembolic prophylaxis consisted of subcutaneous low-molecular-weight heparin.
On day 15, the patient required emergency tracheal intubation and mechanical ventilation for acute respiratory failure. Right pulmonary edema was present on the chest roentgenogram. Transesophageal echocardiography (TEE) showed an increased blood flow velocity (aliasing) in the right pulmonary veins suggesting severe stenosis. A spiral chest computed tomography (CT) scan confirmed the right pulmonary vein anastomotic stenosis (Fig 1). Severe bilateral pulmonary emboli were also diagnosed, with occlusion of the proximal left pulmonary artery (Fig 2). The CT scan did not reveal any thrombus in the inferior vena cava. Venous Doppler imaging of the lower limbs did not show any deep venous thrombosis.
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Fig 1. Spiral chest computed tomography scan shows right pulmonary venous anastomotic stenosis (arrow) and ipsilateral lung edema.
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Fig 2. Spiral chest computed tomography scan reveals occlusion of the left pulmonary artery (the dashed line represents 1.96 cm).
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The patient underwent emergency operation through bilateral thoracotomies associated with a transverse sternotomy. Cardiopulmonary bypass was initiated between the vena cava and the ascending aorta, and pulmonary embolectomy was first performed. The left pulmonary artery was occluded by a nonadherent thrombus at the level of the arterial pulmonary anastomosis. The thrombus was removed using a special forceps, then a suction device. The proximal right pulmonary artery was free of thrombus. The right pulmonary vein anastomosis was refashioned. After thromboembolectomy, the patient was anticoagulated with intravenous heparin and subsequently with oral anticoagulant.
Postoperatively, a pulmonary infarction developed in the left inferior lobe, which required lobectomy for infection 3 weeks later. The patient was afterwards discharged into a rehabilitation facility. At 6 months, she was doing well.
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Comment
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Unilateral pulmonary edema can be caused by contralateral pulmonary embolism, reexpansion edema, acute mitral regurgitation, bronchial stenosis, or pulmonary venous obstruction. After lung transplantation, ischemia–reperfusion injury as well as pulmonary veins stenosis (PVS) can be causes of unilateral pulmonary edema.
Severe PVS is a rather rare complication after lung transplantation. It was reported by Griffith and colleagues [3] in 1 of 60 single-lung recipients and in 1 of 74 double-lung recipients. TEE is considered the gold standard for the diagnosis of PVS in lung transplant patients, although its diagnostic value has not been assessed in large series [3]. TEE has the advantage of detecting PVS in the operating room, thus allowing adequate revision without delay and preventing severe lung damage.
PVS is considered severe and can lead to graft failure when the anastomotic diameter is less than 2.5 mm [4, 5]; at between 2.5 and 5 mm, the PVS is considered moderate. In a series reported by Cherqui and colleagues [4], 4 patients with moderate PVS had an uneventful course after lung transplantation.
Our patient had an infraclinical right PVS, with a 6-mm anastomotic diameter on CT scan. The embolic occlusion of the left pulmonary artery redirected most of the cardiac output to the right lung, rendering this right pulmonary vein functionally critical and causing a rapidly aggravating unilateral lung edema. With this case, we report acute decompensation of asymptomatic PVS by contralateral pulmonary embolism in a lung transplant patient. Although TEE was suggestive of severe PVS (increased blood flow velocity), the acute onset of respiratory failure 2 weeks after an uneventful postoperative course led us to consider the diagnosis of pulmonary embolism. The latter was confirmed by CT scan performed before surgery.
An undetected pulmonary embolism would have had serious intraoperative consequences:
- 1 Trying to refashion the venous anastomosis without cardiopulmonary bypass would have been impossible because of the presence of pulmonary embolism.
- 2 Weaning from bypass would have been difficult, the sole functioning lung being still severely edematous.
- 3 The risk of pulmonary infarction after pulmonary embolism is high in lung transplant patients owing to the absence of bronchial circulation. Therefore, a surgically untreated pulmonary embolism would have led to left lung infarction and subsequent left pneumonectomy.
PVS after lung transplantation usually reflects a technical error. Typically, venous anastomotic stenosis is observed when the donor’s pulmonary vein cuff has not been trimmed enough. This was not the case in our patient, where the anastomotic stenosis was related to a major size mismatch between the large donor and the small recipient’s pulmonary veins (Fig 3). From a technical standpoint, two surgical strategies are possible to avoid anastomotic stenosis in this setting.
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Fig 3. (A) Severe size mismatch between the large donor and the small recipient’s pulmonary veins. (B) Venous anastomotic stenosis as a consequence of size mismatch. (C) The venous anastomosis was refashioned using an open technique. The left atrial incision was extended superiorly and inferiorly to accommodate the large donor’s pulmonary veins.
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The first is performing the anastomosis under cardioplegic heart arrest. No lateral clamping of the left atrium is then necessary, allowing a larger and more appropriate venous anastomosis.
The second surgical strategy is more complex and consists of anastomosing the right superior pulmonary vein to the left atrium (under lateral cross-clamping), followed by reimplantation of the inferior pulmonary vein into the superior pulmonary vein. This is possible when the donor’s pulmonary veins are larger than the recipient’s.
In conclusion, our patient had a secondary decompensation after lung transplantation. In such a case, even in the presence of a well-documented PVS, other decompensating factors that might need specific treatment should be ruled out.
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References
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- Burns KE, Iacono AT. The prevalence of clinically unsuspected pulmonary embolism in mechanically ventilated lung transplant recipients Transplantation 2004;77:692-698.[Medline]
- Noda S, Sundt TM, Lynch JP, Trulock EP, Sundaresan S, Patterson GA. Pulmonary embolectomy after single-lung transplantation Ann Thorac Surg 1997;64:1459-1461.[Abstract/Free Full Text]
- Griffith BP, Magee MJ, Gonzales IF, et al. Anastomotic pitfalls in lung transplantation J Thorac Cardiovasc Surg 1994;107:743-754.[Abstract/Free Full Text]
- Michel-Cherqui M, Brusset A, Liu N, et al. Intraoperative transesophageal echocardiographic assessment of vascular anastomoses in lung transplantationA report on 18 cases. Chest 1997;111:1229-1235.[Medline]
- Huang YC, Cheng YJ, Lin YH, Wang MJ, Tsai SK. Graft failure caused by pulmonary venous obstruction diagnosed by intraoperative transesophageal echocardiography during lung transplantation Anesth Analg 2000;91:558-560.[Abstract/Free Full Text]
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Abstract
Introduction
