Platypnea-Orthodeoxia in Patients on Hemodialysis: A New Approach to Its Pathophysiology and Implications for Treatment

Abstract

Platypnea-orthodeoxia is a poorly understood clinical syndrome resulting in dyspnea and hypoxemia in the upright position, which diminishes with recumbency. Recognition of the disease is limited by its low prevalence and decreased awareness among clinicians. However, understanding the disease, its pathophysiology, its clinical presentation, and the possible therapeutic options is vital in the management of these patients. Here, we present 2 cases of platypnea- orthodeoxia where oxygen saturations worsened with hemodialysis. After highlighting the common features in the clinical pattern of each patient, we present a pressure-mediated pathophysiologic mechanism (in contrast to a previously reported morphologically based hypothesis) to explain the characteristic effects of hemodialysis on hypoxia in platypnea-orthodeoxia. We present a novel diagnostic approach using balloon occlusion testing when the diagnosis is unclear and illustrate how treatments can be tailored to the comorbidities of a specific patient.

Platypnea-Orthodeoxia Syndrome: A Case of Chronic Paroxysmal Hypoxemia

“…9,10 In patients where closure cannot be achieved or is medically unsafe, medical therapy can be considered. 7 In summary, this patient's 30-year history of cryptic hypoxemia may be attributable to POS due to an unrecognized PFO. Identification and closure resulted in resolution of a 30-year history with significant impact on his livelihood.…”

“…3 While the pathophysiology of intracardiac POS is not completely elucidated or uniformly endorsed, there appear to be two, slightly differing theories: the dynamic structuralmediated 1, 2 and dynamic pressure-mediated hypotheses. 7 In both hypotheses there is an assumption of a Btwo-hit^process, consisting of both an underlying anatomic defect and an additional acquired cardiac or pulmonary abnormality associated with a variety of anatomic and systemic processes. 7 In the structural hypothesis, intracardiac POS requires the presence of an interatrial communication, which is most typically a PFO, but may also be an atrial septal defect or fenestrated atrial septal aneurysm.…”

“…7 In both hypotheses there is an assumption of a Btwo-hit^process, consisting of both an underlying anatomic defect and an additional acquired cardiac or pulmonary abnormality associated with a variety of anatomic and systemic processes. 7 In the structural hypothesis, intracardiac POS requires the presence of an interatrial communication, which is most typically a PFO, but may also be an atrial septal defect or fenestrated atrial septal aneurysm. 2,3 In healthy individuals with a PFO, left atrial pressure is slightly higher than right atrial pressure, resulting in a pressure gradient sufficient to functionally close the PFO by abutting the flap of tissue against the septal wall.…”

“…dilated aortic root). 7 Notably, this article indicates that medical symptomatic management focused on controlling right atrial pressure may be possible, whereas therapies previously described in the literature were targeted at closure of the atrial communication.…”

Postural nausea due to platypnea orthodeoxia

“…The literature includes two distinct theories: the dynamic structural-mediated3 and dynamic pressure-mediated hypotheses 4. Both require an underlying anatomical defect, plus an additional acquired cardiac or pulmonary abnormality.…”