|Year : 2021 | Volume
| Issue : 2 | Page : 85-88
Platypnea-orthodeoxia syndrome years after acute pulmonary embolism: Two consecutive cases
Luca Allievi1, Amedeo Bongarzoni2, Barbara Conconi2, Gabriele Tumminello2, Lucia Barbieri3, Stefano Carugo4
1 Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
2 Department of Cardiology, ASST Santi Paolo e Carlo, University of Milan, Milan, Italy
3 Department of Cardiology, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
4 Department of Clinical Sciences and Community Health, University of Milan; Department of Cardiology, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
|Date of Submission||14-Jun-2021|
|Date of Decision||11-Oct-2021|
|Date of Acceptance||13-Oct-2021|
|Date of Web Publication||08-Dec-2021|
Dr. Luca Allievi
Department of Clinical Sciences and Community Health, University of Milan, Via Festa del Perdono 7, 20122 Milan
Source of Support: None, Conflict of Interest: None
Platypnea-Orthodeoxia syndrome (POS) is a rare condition in which dyspnoea and arterial oxygen desaturation are present in the upright position, while in the supine position, they are alleviated. It is observed in the presence of an anatomical (intra- or extracardiac) communication between the right and left heart causing a right-to-left shunt. POS is most frequently caused by a patent foramen ovale (PFO) and usually, the clinical assessment and a transthoracic echocardiograms with bubble study are enough to reach the diagnosis. The only possible treatment of POS is the percutaneous closure of the defect. We describe two cases of POS due to a PFO which manifested itself years after an episode of acute pulmonary embolism (PE), a finding never reported to date in the literature. Few cases describe the relationship between PE and POS, but these conditions may be more closely related than we currently think.
Keywords: Acute respiratory failure, arterial oxygen desaturation, case report, Platypnea-Orthodeoxia syndrome, pulmonary embolism
|How to cite this article:|
Allievi L, Bongarzoni A, Conconi B, Tumminello G, Barbieri L, Carugo S. Platypnea-orthodeoxia syndrome years after acute pulmonary embolism: Two consecutive cases. Ann Clin Cardiol 2021;3:85-8
|How to cite this URL:|
Allievi L, Bongarzoni A, Conconi B, Tumminello G, Barbieri L, Carugo S. Platypnea-orthodeoxia syndrome years after acute pulmonary embolism: Two consecutive cases. Ann Clin Cardiol [serial online] 2021 [cited 2023 May 29];3:85-8. Available from: http://www.onlineacc.org/text.asp?2021/3/2/85/336217
| Introduction|| |
Platypnea-Orthodeoxia syndrome (POS) is a rare finding during clinical practice, in which dyspnoea and arterial oxygen desaturation are present in a sitting or standing position, while they are alleviated in the supine position. POS is caused by intra- or extracardiac shunts between the right and left heart with the mixing of deoxygenated venous blood into the oxygenated arterial blood; both anatomical and functional components are involved in its development. Patent foramen ovale (PFO) is the most frequent cause of POS; it may remain silent for a long time, but in the elderly, several trigger factors may favor the development of a significant right-left shunt leading to POS (e.g., pulmonary embolism [PE]). We describe below two cases of POS due to a PFO, which manifested itself years after an episode of acute PE, a finding never reported to date in the literature.
| Case Series|| |
A 78-year-old woman with arterial hypertension came to the emergency room of our hospital on September 12, 2020, for dyspnea and epigastric pain.
In 2012, she had had a deep vein thrombosis and PE following knee surgery. Since then, she had continued to feel tired with shortness of breath, but no pulmonary hypertension (PH) was found on transthoracic echocardiograms (TTE). In May 2020, she had experienced an episode of acute respiratory failure (ARF): A transcranial Doppler ultrasound detected the presence of a shunt, but its site had not been identified (negative TTE with bubble study and computed tomography angiography [CTA]). After the discharge, fatigue and dyspnea had continued to worsen until the current new episode of ARF.
On blood tests, electrocardiogram, chest X-ray and CTA no pathological features were found, excluding pneumonia or PE. Furthermore, the SARS-CoV-2 nasopharyngeal reverse transcriptase-polymerase chain reaction (RT-PCR) swab test was negative. The arterial blood gas (ABG) test showed hypoxemia and hypocapnia (pH 7.47, pO2 72 mmHg, pCO2 29 mmHg, HCO3-21 mmol/L, SpO2 95% in Venturi Mask [VM] FiO2 50%). She was admitted to the pneumology department with the diagnosis of ARF due to a probable POS by an intrapulmonary shunt. Continuous positive airway pressure (CPAP) was not necessary in this case, but the clinical situation did not improve significantly with the high-flow oxygen therapy with VM. The arterial oxygen saturation was markedly lower in the upright position (SpO2 89%, FiO2 50%) than in the supine position (SpO2 95%, FiO2 50%). The CTA images did not show definite intrapulmonary shunts. The TTE alone did not detect pathological findings except a mild dilatation of the aortic root and aortic regurgitation; conversely, the TTE with bubble study showed a massive presence of microbubbles into the left heart within three cardiac cycles after the opacification of the right heart, but it was not possible to confirm the intracardiac origin of the shunt.
Before moving on to more invasive methods, an abdominal ultrasound excluded liver disease and portal hypertension, ruling out hepatopulmonary syndrome; furthermore, a magnetic resonance angiography did not detect intrapulmonary shunts. A pulmonary angiography with superior and inferior cavography definitely excluded intrapulmonary shunts. Finally, the transoesophageal echocardiogram (TOE) confirmed the presence of an intracardiac shunt through a PFO with an atrial septal aneurysm (ASA) and a deficient aortic rim [Figure 1]. The patient was transferred to the cardiology department and she underwent percutaneous PFO closure on October 15, 2020: A Gore Cardioform Septal Occluder (25 mm) was placed into the interatrial septum (IAS) [Figure 2]. The arterial oxygen saturation in the upright position returned to normal values almost immediately (SpO2 98% without oxygen therapy), and she no longer reported shortness of breath. She was then discharged after 4 days from the intervention (October 19, 2020), and during the subsequent cardiological follow-up, no more symptoms were reported.
|Figure 1: The sequence of a TOE with bubble study during Valsalva maneuver confirming the presence of a significant PFO (patient number 1), modified bicaval view. (a) Bubbles are still not visible in the RA, the large PFO is well visible, (b) crossing of bubbles through the PFO toward the LA, (c) within few cardiac cycles, the LA is filled with bubbles. LA: Left atrium, PFO: Patent foramen ovale, RA: Right atrium, TOE: Transoesophageal echocardiogram|
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|Figure 2: PFO closure (patient number 1). (a) Fluoroscopic image (patient number 1) showing the placement of the Gore Cardioform Septal Occluder (25 mm) in the IAS, (b) 3D-TOE showing the Gore Cardioform Septal Occluder (25 mm) correctly placed in the IAS. IAS: Interatrial septum, TOE: Transoesophageal echocardiogram, PFO: Patent foramen ovale, AO: Ao, aorta (in Figure 1)|
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An 82-year-old woman with arterial hypertension and dyslipidemia came to the emergency room of our hospital on January 16, 2021, for worsening dyspnea.
She had a history of pulmonary tuberculosis, PE in 2014 and, since then, chronic respiratory failure in-home oxygen therapy (3–5 ml/min) without echocardiographic signs of PH.
On blood tests, kidney failure (creatinine 3.86 mg/dL, estimated glomerular filtration rate 10.24 mL/min) and mild systemic inflammation (C-reactive protein 5.6 mg/dL) were found, while the ABG test showed hypoxemia and hypocapnia (pH 7.46, pO2 47 mmHg, pCO2 28 mmHg, lactate 2 mmol/L). The SARS-CoV-2 nasopharyngeal RT-PCR swab test was negative, and the chest X-ray did not detect pathological processes. She was then admitted to the emergency medicine department with the diagnosis of ARF. During hospitalization, the patient's clinical situation did not improve despite the high-flow oxygen therapy (VM and CPAP). A chest computed tomography (CT) scan with contrast excluded PE. A bedside TTE showed only a hyperkinetic left ventricle and a moderate dilatation of the ascending aorta (46 mm), but it was not possible to assess the right heart completely because of the poor echo signal. The ABG test in the sitting position showed oxygen desaturation (pO2 61 mmHg, SpO2 93.5%, FiO2 40%) compared to the test in the supine position (pO2 89 mmHg, SpO2 99%, FiO2 40%), leading us to suspect an intra-or extracardiac shunt. The CT images excluded an extracardiac shunt, while a TTE with bubble study showed a massive presence of microbubbles into the left heart immediately after the opacification of the right heart. Finally, the TOE confirmed the presence of the PFO (tunnel length 12 mm) with an ASA [Figure 3], leading to the diagnosis of POS. Once stability was achieved, she was discharged on January 26, 2021, with the indication of a subsequent percutaneous PFO closure. The procedure was scheduled for February 22, 2021; in the morning before the procedure, the SpO2 was 97% in the supine position and 88% in the sitting position on 3 l/min O2 flow. A Gore Cardioform Septal Occluder (30 mm) was placed successfully into the IAS under TOE guidance [Figure 4]. After the procedure, SpO2 and symptoms gradually improved and no more difference in SpO2 was found between supine and sitting position (94% and 96% on room air, respectively). The patient was discharged without an oxygen supply on February 24, 2021.
|Figure 3: The sequence of a TOE with bubble study during Valsalva maneuver confirming the presence of a significant PFO (patient number 2), modified bicaval view. (a) Bubbles arriving in the right atrium, the large PFO is well visible, (b) crossing of bubbles through the PFO toward the LA, (c) within few cardiac cycles, the LA is filled with bubbles. LA: Left atrium, PFO: Patent foramen ovale, RA: Right atrium, TOE: Transoesophageal echocardiogram|
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|Figure 4: PFO closure (patient number 2). (a) Fluoroscopic image (patient number 2) showing the placement of the Gore Cardioform Septal Occluder (30 mm) in the IAS, (b) 3D-TOE showing the Gore Cardioform Septal Occluder (30 mm) correctly placed in the IAS. IAS: Interatrial septum, TOE: Transoesophageal echocardiogram, PFO: Patent foramen ovale|
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| Discussion|| |
POS is a rare condition, but also underdiagnosed and undertreated, owing to the difficulty to clinically recognize it. The causes of POS may be classified into three categories: intracardiac (most frequent), extracardiac, and miscellaneous; PFO is the most frequent anatomical component involved. Ascending aortic dilatation is the most frequent functional component associated with the development of an intracardiac shunt. The extracardiac shunt is less frequent and may be caused by an intrapulmonary shunt or a ventilation-perfusion mismatch. Other miscellaneous conditions are associated with POS, but the mechanism involved has not been yet understood (e.g., amiodarone lung toxicity, Parkinson's disease, diabetic autonomic neuropathy).
The first step toward the diagnosis is to think about POS: When respiratory symptoms and signs do not respond to the high-flow oxygen therapy, a shunt should be suspected after having excluded any other causative condition. A drop in pO2 >4 mmHg or SpO2 >5% from a supine to an upright position is observed in this condition.
Usually, a TTE with bubble study confirms an intracardiac shunt if microbubbles appear into the left heart within 3–6 cardiac cycles; if they appear later, an intrapulmonary shunt is more likely and a CT pulmonary angiography should be performed to confirm it.
The percutaneous closure of the septal defect is the only possible treatment to reduce symptoms, but it is a safe and effective procedure: After the closure, the improvement in symptoms is seen in more than 95% of patients and usually, the patient can return to his normal activities. Probably, patients with POS could be at a higher risk of paradoxical embolism (few cases are described in the literature, because of the low prevalence of POS), due to the relevant right-to-left shunting through the PFO: This may represent one more reason to proceed to the PFO closure besides the improvement in symptoms.
Unfortunately, symptoms can persist after the PFO closure, due to a residual shunt or a misdiagnosis; hence, the importance of carefully excluding any possible cause of persistent hypoxemia before the shunt closure.
Platypnea-Orthodeoxia syndrome and pulmonary embolism
PE is a differential diagnosis for POS, but it also may be a trigger factor, even if not so many cases are reported in the literature. The hypothesized mechanism is related to an acute increase in the right atrial pressure, leading to the development of a significant right-to-left shunt. Usually, POS develops immediately after an episode of acute PE, and dyspnoea continues despite the correct use of anticoagulants. However, as seen, the development of POS years after an episode of PE is possible, but it had never been reported to date. In addition to the presence of previous PE, a large PFO was found in both patients with a massive right-to-left shunt during the Valsalva maneuver. We think that the acute PE and raise in the right atrial pressure led to a significant PFO widening, but the hemodynamic compensation together with the decrease in the right atrial pressure probably made POS not evident immediately after the acute episode. Conversely, a subsequent episode of hemodynamic decompensation or volume overload could have led to the manifestation of POS, hidden so far. Both patients never experienced PH, excluding this possibility.
However, it must be taken into account that if patients had had low or low-intermediate risk PE with low right ventricular systolic pressure during the acute period (unfortunately not derivable from the history), it is unlikely that the described mechanism would apply and the association of PE and PFO in these cases could be coincidental. Furthermore, another possible cause of POS is a pulmonary disease with ventilation/perfusion mismatch, which could have led to POS in the second patient (having a history of pulmonary tuberculosis and long-term oxygen therapy).
In any case, the development of POS in two patients with a very similar history and having PE as the most important event must make us suspect the existence of a relationship between these two conditions.
| Conclusion|| |
POS is rare, but it should be recognized before the onset of an ARF, even if many times it is difficult to do. Intracardiac shunts through a PFO are the most frequent causes of POS. Usually, the clinical assessment and a TTE with bubble study are enough to reach the diagnosis; the only possible treatment of POS is the shunt closure. Acute PE can be a trigger factor for POS development, but it may also manifest years after an acute episode of PE. Therefore, especially with a history of PE, it is important to suspect POS when high-flow oxygen therapy does not improve hypoxemia and arterial oxygen saturation after having excluded any other possible disease involved. In the literature, few cases describe the relationship between PE and POS, but these conditions may be more closely related than we currently think.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]