Ann Thorac Surg 2007;83:1524-1526
© 2007 The Society of Thoracic Surgeons
Case Reports
Platypnea-Orthodeoxia Syndrome After Pneumonectomy Relieved by Mediastinal Repositioning
Christophoros Kotoulas, PhD, FETCSa,e,*,
Konstantinos Patris, MD, DEAAa,e,
Konstantinos Tsintiris, MDa,b,
Antonios Zoumboulides, MDc,
Kiriakos Lazarides, PhDd,
Georgios Laoutides, MDe
a Cardiothoracic Surgery Department, Manchester Royal Infirmary, Manchester, United Kingdom
b Department of Pneumonology, General Military Hospital of Athens, Athens, Greece
c Department of Nuclear Medicine, General Military Hospital of Athens, Athens, Greece
d Department of Cardiology, General Military Hospital of Athens, Athens, Greece
e Cardiothoracic Surgery Department, General Military Hospital of Athens, Athens, Greece
Accepted for publication November 1, 2006.
* Address correspondence to Dr Kotoulas, 38 Kifissias Ave, Athens, 11526, Greece (Email: chrkotoulas{at}hol.gr).
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Abstract
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Platypnea-orthodeoxia is a rare syndrome characterized by hypoxemia in the upright position after pneumonectomy and relieved by recumbency. This syndrome is often a post-pneumonectomy complication due to intracardiac shunt, usually at the atrial level. We report a case after right pneumonectomy without interatrial shunt. The patient was successfully treated with a silicone prosthesis implant in the post-pneumonectomy space. We believe that correction of this clinical situation has not been previously described.
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Introduction
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Platypnea-orthodeoxia syndrome (POS) is a rare clinical entity consisting of dyspnea and arterial hypoxemia induced by upright posture and relieved by recumbency [1, 2]. Although POS has been described in a variety of clinical contexts, it is a rare complication after pneumonectomy. It is usually due to a right-to-left interatrial shunt (RLIAS) [1, 3]. We report a unique case of POS after a right pneumonectomy without RLIAS. This case report describes the clinical and imaging findings, the therapeutic approach, and the possible pathophysiologic mechanism.
A 46-year-old man underwent mediastinoscopy and right pneumonectomy for a T2N1M0, poorly differentiated squamous-cell carcinoma. He had an uneventful recovery and was discharged home. Two months later he presented with progressive shortness of breath with no evident findings on clinical examination. A chest roentgenogram revealed the typical post-pneumonectomy findings with a deviation of the mediastinum to the right, and hyperinflation of the left lung. The patient was started on chemotherapy. A week later he complained of malaise and dyspnea at rest without signs of impaired venous return. Routine hematology and biochemical blood analysis were unremarkable. Arterial blood gases on room air showed PO2 38 mm Hg in a sitting position. In the erect position and on 4 L/min of oxygen through a nasal cannula, the patient’s arterial blood gases revealed SaO2 of 85%, a PO2 of 46.7 mm Hg, with a heart rate of 130 bpm, and blood pressure of 100/65 mm Hg. While in the supine position, his SaO2 was 94%, his PO2 was 72.1 mm Hg, with a heart rate of 85 bpm, and his blood pressure was 125/85 mm Hg. Chest computed tomographic scan with contrast showed rotation of the heart to the right posterior thorax with external compression of the right chambers. The left lung was herniating across the midline, but without compression of the bronchi. Fiberoptic bronchoscopy under local anesthesia revealed an intact bronchial stump and normal left bronchial tree without evidence of malacia. Transthoracic echocardiography showed a small right atrium. The right atrial diameter was 21.4 mm in the supine position and 7.4 mm in the erect position. There was no tricuspid pathology and no intracardiac shunt (Figs 1A,
1B). Right heart catheterization revealed a right atrial pressure of 9 to 10 mm Hg. It was not possible to advance the catheter into the right ventricle. Right heart angiography confirmed a narrow and rotated right atrium. There was no intracardiac shunt. A pulmonary ventilation-perfusion scan showed homogenous distribution of the radioisotope without defects but with ventilation-perfusion mismatch between the two postures (Fig 2). Magnetic resonance imaging with contrast confirmed dilatation of the superior vena cava, and a deformed and compressed right atrium. The cardiac output was 4 L/min (cine-balanced fast field echo and Q-flow techniques).
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Fig 1. Transthoracic echocardiography: rotation and narrowing of the right atrium, (A) sized 21.4 mm in the supine position and (B) 7.4 mm in the erect, without intracardiac shunt. (Ao = aorta; RA = right atrium; RV = right ventricle.)
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The patient deteriorated with breathlessness, tachycardia, and hypotension. We attributed the hemodynamic instability to compression of the right heart in the absence of an intracardiac shunt. A right thoracotomy was performed. There were no adhesions in the post-pneumonectomy space. When the space was opened, the mediastinum repositioned itself to the midline and the right atrium was decompressed. Silicone breast prosthesis (600 mL) was implanted in the right pleural cavity to maintain mediastinum in the midline position and was stabilized with Prolene mesh (Ethicon, Somerville, NJ) against the mediastinal pleura to prevent right heart compression. The patient had an uneventful recovery and he was asymptomatic. Transthoracic echocardiography demonstrated that the diameter of the right atrium was 29 mm in the supine position, whereas his PO2 was 90.3 mm Hg and his SaO2 was 97% on room air. The patient subsequently received chemotherapy and radiotherapy treatments and died due to recurrent disease 35 months later.
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Comment
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Platypnea was reported by Butchell in 1949 [2]. Platypnea-orthodeoxia syndrome was described for the first time by Robin in 1976 [2]. Nevertheless the cause remains unclear, as fewer than 50 cases have been reported [2].
It seems that POS is associated with three groups of disorders: (1) intracardiac shunts, (2) anatomic pulmonary vascular shunts, and (3) pulmonary parenchymal shunts [4]. Right-to-left interatrial shunt due to an atrial septal defect or patent foramen ovale is the most common cause, particularly after pneumonectomy [1]. POS due to intracardiac shunt is based on altered anatomic relationships between vena cavae and the atrial septum. This causes preferential flow from the inferior vena cava through defect or patent foramen ovale toward the left atrium, even in the absence of a pressure gradient [5]. In our case the detailed work-up did not reveal any RLIAS. We hypothesize that hyperinflation of the left lung, shifting of the mediastinum to the right, and rotation of the heart-reduced blood return to the right heart. Furthermore, hyperinflation of the left lung may have changed ventilation-perfusion relationships due to redistribution of ventilation-perfusion zones, leading to shunting [3]. This extracardiac shunt produced hypoxemia in the upright position due to the drop in the preload. The condition seemed to improve in the supine position as the right atrial diameter increased and the cardiac output almost normalized.
One of the characteristics of POS is a symptom-free period after the initial operation until the development of the clinical syndrome. This ranges from days to months as it was in this case (ie, 2 months) [1].
In any patient presenting with dyspnea and hypoxemia after pneumonectomy, POS should be one of the differential diagnoses. Although transthoracic echocardiography or transesophageal echocardiography may establish the diagnosis, especially in cases of RLIAS, a detailed diagnostic work-up is needed in most cases to exclude other pathologies [6]. In our case, although no transesophageal echocardiography was performed, transthoracic echocardiography and cardiac catheterization showed neither intracardiac shunt nor cardiac dysfunction. Fiberoptic bronchoscopy under local anesthesia excluded the diagnosis of post-pneumonectomy syndrome [7]. A ventilation-perfusion scan and a computed tomographic scan with contrast excluded pulmonary embolism and suggested shunting due to mismatch. A magnetic resonance scan revealed the anatomic anomaly that guided our successful intervention.
Treatment of POS depends on the cause. Closure of the culprit defect is the treatment in RLIAS cases. In non-RLIAS cases management is usually conservative [5]. Unfortunately it failed in our case. When the patient deteriorated we decided to proceed with surgery. By implanting the silicon prosthesis we repositioned the mediastinum toward the midline and decompressed the right atrium. Due to lack of adhesions in the pleural cavity we stabilized the mediastinum by firm application of mesh over the mediastinal pleura. We believe this clinical condition has not been described in the past. Casanova Viudez and colleagues [8] reported a similar therapeutic strategy in a case of post-pneumonectomy syndrome after left pneumonectomy with acute vascular compromise [8]. Our case is different because the symptoms were typical of POS but without evidence of the post-pneumonectomy syndrome.
We report the successful outcome of the surgical treatment in this case without intracardiac shunt. We emphasize the difference in cause and treatment compared with those with intracardiac shunt. Correction of the mediastinal shift with silicone implants has not been described in the past.
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References
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- Acharya SS, Kartan R. A case of orthodeoxia caused by an atrial septal aneurysm Chest 2000;118:871-874.[Medline]
- Mercho N, Stoller JK, White RD, Mehta AC. Right-to-left interatrial shunt causing platypnea after pneumonectomy: a recent experience and diagnostic value of dynamic magnetic resonance imaging Chest 1994;105:931-933.[Medline]
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- Casanova Viudez J, Marinan Gorospe M, Rumbero Sanchez JC. Surgical repair of postpneumonectomy syndrome with vascular compromise Arch Bronconeumol 2002;38:51-54.[Medline]
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Abstract
Introduction
