Platypnoea–orthodeoxia syndrome due to deformation of the patent foramen ovale caused by a dilated ascending aorta: a case report

Abstract

Background Platypnoea–orthodeoxia syndrome (POS) is characterized by dyspnoea and arterial desaturation in the sitting position. Although its pathophysiology is complex and still needed to be investigated, the disease is one of the clinical situations which should be immediately and adequately managed by health care workers from the initial presentation. Case summary A 66-year-old woman with a history of systemic lupus erythematosus, deep vein thrombosis, and lumbar compression fracture was admitted for evaluation of the sudden onset of dyspnoea, while in the sitting position that was relieved on placing her in the supine position. Her transoesophageal echocardiogram did reveal a deformity in the patent foramen ovale (PFO) structure with a wide gap due to aortic compression, which was markedly different from that observed in the supine position, along with massive right-to-left shunting caused by redirected venous return due to a persistent Eustachian valve. With the computed tomography and angiograms, POS was diagnosed. Then, the patient received aortic replacement and patch closure of PFO, and her symptoms were completely resolved. Discussion Platypnoea–orthodeoxia syndrome is a condition with quite unique features and needs multiple clinical measures for the diagnosis and medical management. For all health care workers, it is essential to have a high suspicion in order to detect POS in patients with unexplained dyspnoea. Echocardiography plays a major role in establishing the diagnosis and offering the choice of therapeutic options.

Platypnea-orthodeoxia Syndrome Due to Right Ventricular Inflow Tract Obstruction Caused by an Elongated Ascending Aorta: Usefulness of Three-dimensional Cardiac Computed Tomography Imaging in the Sitting Position

“…Regarding the treatment of POS, there are cases in which only shunt closure was performed (6,10), or in which the ascending aorta was surgically treated (7,13). In our case, PFO closure was the only surgical treatment because cardiac catheterization confirmed that PFO closure with a balloon did not have a significant hemodynamic impact.…”

“…Subsequently, right-to-left shunt must be confirmed. TEE is crucial for direct visualization of the shunt flow or structural abnormalities and has been used in some reported cases (4)(5)(6)(7)(8)(9)(10)(11)(12)(13).…”

“…Previous reports have demonstrated different functional components, including elongation or aneurysm of the ascending aorta (5-7, 10, 11, 13), compression by extracardiac structures (3,14), tricuspid regurgitation (4, 9), pericardial disease (8), or pulmonary embolism (12). The most common condition associated with POS is PFO with an elongated ascending aorta, but even in these cases, various mechanisms have been reported, including compression of the right atrium (6,10,13), rotation of the entire heart (11), atrial septum deformation (5,7), or changes in the direction of venous return via the inferior vena cava (7). In our case, 3D cardiac CT and TEE suggested that right-to-left shunt enhancement in the sitting position might have been caused by a restricted blood flow to the right ventricle and deformation of the atrial septum by the elongated ascending aorta.…”

“…It is reportedly caused by right-to-left shunt, which is augmented by anatomical changes in the upright posture (2). A small number of cases of POS have been reported (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14), and their pathogenesis is complex and not uniform.…”

Increased Mobility of the Atrial Septum in Aortic Root Dilation: An Observational Study on Transesophageal Echocardiography

“…The anatomic relation between the aortic root and atrial septum first appeared on case reports of patients with platypnea–orthodeoxia syndrome (Medina et al, 2001 ; Chopard and Meneveau, 2013 ; Hasegawa et al, 2020 ). An enlarged aorta could geometrically impinge a shortening in the anteroposterior atrial septal length, consequently augmenting the atrial septal mobility (ASM) ( Supplementary Video ).…”