Interatrial Right-to-Left Shunt after Lung Surgery: Diagnostic Value of Perfusion Lung Scanning

Cardiac Platypnea-Orthodeoxia Syndrome: A Rare Case of Flow-Directed, Right-to-Left Shunt via a Patent Foramen Ovale Exacerbated by Aortic Root Enlargement

Cardiac platypnea-orthodeoxia is a unique clinical syndrome characterized by dyspnea and deoxygenation when moving from a supine to an upright position. In this case report, we detail the experience of a 78-year-old male with persistent hypoxemia following a paradoxical embolic ischemic stroke. Despite proper management of his respiratory symptoms, the patient continued to be affected by marked dyspnea and hypoxemia, particularly when upright or in a right-sided decubitus position. Subsequent investigation revealed that his hypoxemia was a result of cardiac platypnea-orthodeoxia syndrome (POS). This condition was attributed to the enlargement of his aortic root and ascending aorta, coupled with a counterclockwise rotation of the heart axis. These factors facilitated a flow-directed, right-to-left interatrial shunt through a patent foramen ovale, even in the absence of elevated right heart pressures.

[Platypnea-orthodeoxia syndrome secondary to pneumonia: Two cases]

INTRODUCTION

The platypnea-orthodeoxia syndrome is a rare situation characterized by the appearance of dyspnea and/or hypoxemia during the transition to orthostatism.

OBSERVATIONS

We report the case of two patients, who presented with a platypnea-orthodeoxia syndrome following pneumocystis pneumonia and COVID-19, revealing an intracardiac communication with a right-left shunt on contrast ultrasound.

CONCLUSION

This syndrome can be detected easily at the bedside with positional maneuvers and the shunt demonstrated by a hyperoxia test. Non-reversible situations may require correction of the anatomical anomaly by transcatheter intervention or surgery.

Patent Foramen Ovale-Induced Platypnea-Orthodeoxia Syndrome: A Case Report and Literature Review

Platypnea-orthodeoxia syndrome (POS) is a rare condition characterized by dyspnea and hypoxia worsening in the upright position and relieved in the recumbent position. POS can result from anatomical or functional conditions that cause interatrial communication or deformity of the atrial septum. Investigations with imaging and cardiac catheterization can aid in the evaluation. In cases where POS is caused by intracardiac shunting without pulmonary hypertension, closure of the intracardiac shunt can be curative. We report a case of POS in a 54-year-old male who was treated successfully with percutaneous closure of a patent foramen ovale (PFO).

Platypnoea-orthodeoxia syndrome due to a right-to-left interatrial shunt following pneumonectomy

A 62-year-old man presents with breathlessness 6 months following right pneumonectomy for lung adenocarcinoma. Previous investigations had not yielded a diagnosis and his symptoms were progressing. The patient described worsened symptoms when stood up (platypnoea), with profound hypoxia until laid supine (orthodeoxia). Platypnoea-orthodeoxia syndrome due to a right-to-left interatrial shunt was diagnosed on contrast-enhanced transoesophageal echocardiography with the patient undergoing successful percutaneous patent foramen ovale closure. Patent foramen ovale is often asymptomatic with a population prevalence of around 20%-30%. Anatomical shifts postpneumonectomy can open, or worsen a previously closed interatrial communication leading to right-to-left shunting of blood. Platypnoea-orthodeoxia is under-recognised, impairing quality of life and patient outcome. Investigations can be falsely reassuring, or poorly sensitive for the causative pathology. Percutaneous closure is safe with high success rates and this case highlights the need for a high index of suspicion for shunts, particularly in postpneumonectomy patients.

Posture Dependent Hypoxia Following Lobectomy: The Achilles Tendon of the Lung Surgeon?

BACKGROUND

Platypnoea-Orthodeoxia Syndrome is an uncommon phenomenon characterized by dyspnea/arterial desaturation in the standing position, resolving in recumbency. Some patients present with Platypnoea-Orthodeoxia Syndrome in the early-or-late post-operative period after major lung resection (lobectomy/pneumonectomy). The main cause of Platypnoea-Orthodeoxia Syndrome is an intracardiac anomaly (Patent Foramen Ovalis/Atrial Septal Defect) leading to right-to-left shunt.

OBJECTIVES

To identify the causes of post-lobectomy Platypnoea-Orthodeoxia Syndrome, and the possible pathophysiologic mechanism.

METHODS

A Pubmed database-EMBASE systematic review was performed in order to find all reports, reporting the occurrence of dyspnea/hypoxemia after lobectomy.

RESULTS

8 studies were found concerning ten patients during the period from 1983-2019.There was 6 male/4 female. The mean age was 62 years. All patients underwent resection of the right lung. The time-interval between the operation and the Platypnoea-Orthodeoxia Syndrome was from 2 days to 3 years. A Patent Foramen Ovalis was present in 90% and in 10% an Atrial Septal Defect was diagnosed. The mean Right Atrial Pressure was 7.5 mmHg, the mean Left Atrial Pressure was 6.6 mmHg and the mean Pulmonary artery pressure was 18.5 mmHg. The mean size of the interatrial communication was 1.62 cm. The inter-atrial communication was closed by open-chest surgical procedure in 3 cases (30%) and in 7 patients (70%) a percutaneous transcatheter device was implanted.

CONCLUSIONS

Platypnoea-Orthodeoxia Syndrome after lobectomy is a rare cause of post-operative dyspnea/hypoxia. It is the result of right-to-left shunt via an interatrial communication. Mediastinal relocation, stretching of the atrial septum and aortic root dilatation are among the functional elements necessary for the Platypnoea-Orthodeoxia Syndrome manifestation.

The multiple dimensions of Platypnea-Orthodeoxia syndrome: A review

Platypnea-Orthodeoxia syndrome (POS) is a rare clinical entity characterized by dyspnea and arterial desaturation while in the upright position. The various pathophysiologic mechanisms leading to POS has puzzled clinicians for years. The hypoxia in POS has been attributed to the mixing of the deoxygenated venous blood with the oxygenated arterial blood via a shunt. The primary mechanisms of POS in these patients can be broadly classified based on intracardiac abnormalities, extracardiac abnormalities and miscellaneous etiologies. A Patent Foramen Ovale (PFO) was the most common reported site of an intracardiac shunt. In addition to PFO, intracardiac shunt leading to POS has been reported from either an Atrial Septal Defect (ASD) or an Atrial Septal Aneurysm (ASA). Most patients with an intracardiac shunt also demonstrated a secondary anatomic or a functional defect. Extracardiac causes of POS included intra-pulmonary arteriovenous malformations and lung parenchymal diseases. A systematic evaluation is necessary to identify the underlying cause and institute an appropriate intervention. We conducted a review of literature and reviewed 239 cases of POS. In this article, we review the etiology and pathophysiology of POS and also summarize the diagnostic algorithms and treatment modalities available for early diagnosis and prompt treatment of patients presenting with symptoms of platypnea and/or orthodeoxia.

Cardiac platypnea-orthodeoxia syndrome: an often unrecognized malady

Platypnea-orthodeoxia syndrome (POS) is a rare but clinically important form of dyspnea. The syndrome is characterized by dyspnea and arterial oxygen desaturation that occurs in the upright position and improves with recumbency. In cardiac POS, an atrial septal defect or patent foramen ovale allows communication between the right- and left-sided circulations. A second defect, such as a dilated aorta, prominent eustachian valve, or pneumonectomy, then contributes to right-to-left shunting through the interatrial connection. Diagnosis is made through pulse oximetry to confirm orthodeoxia and through transesophageal echocardiography with bubble study to visualize the shunt. Although data are limited for this rare syndrome, percutaneous closure has thus far proven safe and effective.