Positional cyanosis reveals platypnea-orthodeoxia-syndrome.

Platypnea-orthodeoxia syndrome is a rare cause of dyspnea, which presents upon standing and resolves when supine. Etiology is multifactorial with a functional component and an anatomical shunt. The most commonly reported shunt is an atrial septal defect, however a shunt can occur in advanced hepatic or pulmonary disease. Treatment is dependent on the type and location of the shunt. In atrial septal defects percutaneous repair is preferred. To follow is a case of iatrogenic platypnea-orthodeoxia syndrome secondary to heart failure guideline directed medical therapy in a 79 year-old woman.

Introduction

Shortness of breath or dyspnea is a common symptom accounting for up 25% of ambulatory clinic consultations. Dyspnea has a vast differential diagnosis, with the pulmonary or cardiovascular systems accounting for the majority of cases.

Case report

A 79 year old woman with permanent atrial fibrillation and New York Heart Association class II symptoms presented to our clinic for evaluation. Clinical investigation revealed a largely benign physical exam apart from an irregularly irregular heartbeat, routine laboratory studies were all within reference ranges. Subsequent transthoracic echocardiography (TTE) revealed heart failure with reduced ejection fraction (HFrEF), right ventricular systolic dysfunction, and a severely dilated right atrium. There was evidence of an atrial septal shunt (Fig. 1), however agitated saline or contrast was not preformed. Etiology of HFrEF at this time was believed to be caused by long standing atrial fibrillation, invasive angiography was offered and declined. Following image, review HFrEF guideline directed therapy (GDT) was initiated. Patient underwent repeat evaluations at regular intervals for therapy monitoring and medication titration. Within six weeks of treatment patient's presenting symptoms had resolved. However, she reported a recent change in appearance of her lips. Within 10 minutes of standing her lips would change from flesh colored pink to blue (Fig. 2). Upon closer physical examination, with patient standing, cyanosis was also noted on her fingertips (Fig. 3). While seated the patient's peripheral capillary oxygen saturation (SpO2) was greater than 95%. Within one minute of standing her SpO2 dropped to 88%. On further questioning, the patient endorsed relatively new dyspnea upon standing and with activity preformed while standing which resolved with sitting or lying down. This complaint differed from her original presenting complaint. Prior to GDT initiation patient complained of dyspnea when supine or with extended exertional activity. As, this was a significant change in her clinical exam a repeat TTE was obtained. Repeat TTE imagining further characterized her septal shunt as a patient foramen ovale (PFO) with left-to-right shunting while supine with flow reversed to right-to-left upon standing. To further characterize the shunt, cardiac magnetic resonance image (cMRI) was obtained. Imaging confirmed a large ASD with a Qp/Qs ratio of 1.5 (Fig. 4). Subsequent, right heart catheterization was remarkable for normal cardiac output and normal pulmonary artery pressure, an oximetry run was not preformed. Patient was diagnosed with Platypnea orthodeoxia syndrome (POS). Prior to HFrEF GDT direction of patient's atrial septal shunt was from left to right, and thus patient did not experience symptoms of POS. After therapy initiation, which off loaded a percentage of left ventricular pressure, her shunt reversed flow to right to left. Essentially, iatrogenic POS. In addition to her reported symptoms, the patient's hypoxemia required intervention and she underwent percutaneous PFO repair. Following recovery from her repair procedure, she was closely examined while standing. Observation during this period did not reveal central or peripheral cyanosis, and her SpO2 remained greater than 95%. Upon subsequent follow up, patient's HFrEF symptoms remained controlled and no observed return of cyanosis. Interestingly her repeat TTE preformed after approximately 8 weeks of GDT revealed a significant improvement in her ejection fraction.

Fig. 1

Transthoracic echocardiography demonstrating atrial septal defect by color Doppler.

Fig. 2

79 year old woman with central cyanosis. Lips changed from patient's normal skin color to blue within 10 minutes of standing. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)

Fig. 3

79 year old woman with cyanotic finger tips. A: dorsal surface. B: volar surface.

Fig. 4

Cardiac Magnetic Resonance Imaging (cMRI). Cross sectional section revealing large right atrium and moderate sized atrial septal defect (arrow).

Discussion

POS describes an uncommon condition of positional dyspnea (platypnea) and hypoxemia, (orthodeoxia). This occurs when the patient is standing or even sitting upright and resolves when recumbent. Essentially, opposite of what one might expect with heart failure [1]. True prevalence of POS is unknown a literature review in 2012 found 105 articles with a total of 188 patients with POS [2]. Pathophysiology is incompletely understood, but it appears there is both a functional (pulmonary and/or cardiac pathology) and an anatomic shunting component. The most commonly described shunt is intra-atrial, a PFO or atrial septal defect (ASD), but POS has been observed with pulmonary and portal-systemic shunts in hepatic disease [3]. Upon standing the atrial septum stretches, enlarging the PFO or ASD. This increase alters direction of blood flow returning to the heart via the inferior vena cava. Blood is then directed into the left atrium bypassing pulmonary circulation, resulting in hypoxemia [3]. Diagnosis requires contrast enhanced TTE performed with patient supine and standing [4]. Identifying the hemodynamic consequences of the shunt can aid in shunt repair planning. This is done by calculating Qp/Os ratio, in normal individuals this ratio is around one, in patients with left-right shunts this ratio is > 1, in patients with right-left shunts this ratio is < 1 [5]. The Qp/Qs ratio obtained through cMRI was calculated while the patient was supine. The cause of POS determines the treatment. PFOs and ASDs can be closed with surgery or percutaneous intervention, with the later preferred [4].

Conclusion

Platypnea-orthodeoxia syndrome (POS) is a rare cause of dyspnea in which a sensation of breathlessness is caused by position-dependent hypoxemia; dyspnea is improved in the recumbent position and worsened with sitting or standing [1]. POS should be considered when patients describe this unique context of dyspnea.

Disclosures

The authors have no disclosure information. The views expressed herein are those of the authors and do not reflect the official policy or position of Tripler Army Medical Center, the US Army Medical Department, the US Army Office of the Surgeon General, the Department of the Army, the Department of Defense or the U.S. government.

Declaration of competing interest

The authors do have not any financial conflicts of interest to report.