Potential Role of Patent Foramen Ovale in Exacerbating Hypoxemia in Chronic Pulmonary Disease

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).

Unexplained hypoxemia in COPD with cardiac shunt

In Chronic Obstructive Pulmonary Disease (COPD), hypoxemia is associated with multiple underlying mechanisms, of which one of the most significant is ventilation-perfusion (V/Q) mismatch, which is correctable with supplemental oxygen (O₂) therapy. Hypoxemia that is refractory to very high concentration of inspired O₂ can be indicative of cardiac defect with shunt, e.g., a patent foramen ovale (PFO) with right-to-left (R-T-L) shunt. In hypoxemic COPD patients, the diagnosis of a PFO requires a heightened sense of clinical suspicion along with careful assessment of other underlying possibilities. Platypnea-orthodeoxia and a non-response to the hyperoxia test, while not diagnostic, increase suspicion. A correct diagnosis of interatrial bypass needs to be confirmed with transthoracic echocardiogram and contrast transesophageal echocardiography. Presently, no data are available supporting the effectiveness of PFO closure in COPD patients to relieve symptoms and correct hypoxemia.

We report a case of hypoxemic COPD with platypnea-orthodeoxia syndrome due to PFO. The decision of its closure with device after echocardiographic evaluation of right ventricular function has completely corrected refractory hypoxemia with improvement of SpO₂ and functional capacity. Thus, in selected COPD with refractory hypoxemia, closure of PFO should be considered as novel therapeutic target with improvement of quality of life and less likelihood of hospitalization.

An unusual case of orthodeoxia

Progressive hypoxia in hospitalized patients can be due to many etiologies, especially in patients with multiple comorbidities. More unusual causes of hypoxia, such as patent foramen ovale (PFO) with a right to left shunting in the absence of elevated right atrial pressures, should be considered when workup does not reveal a specific etiology. <Learning objectives: Hypoxemia due to a right-to-left atrial shunt with normal pulmonary arterial pressures can be seen in the aortic aneurysm patients.>.

Association Between Arterial Oxygen Saturation and Lung Ultrasound B-Lines After Competitive Deep Breath-Hold Diving

Breath-hold diving (freediving) is an underwater sport that is associated with elevated hydrostatic pressure, which has a compressive effect on the lungs that can lead to the development of pulmonary edema. Pulmonary edema reduces oxygen uptake and thereby the recovery from the hypoxia developed during freediving, and increases the risk of hypoxic syncope. We aimed to examine the efficacy of SpO₂, via pulse-oximetry, as a tool to detect pulmonary edema by comparing it to lung ultrasound B-line measurements after deep diving. SpO₂ and B-lines were collected in 40 freedivers participating in an international deep freediving competition. SpO₂ was measured within 17 ± 6 min and lung B-lines using ultrasound within 44 ± 15 min after surfacing. A specific symptoms questionnaire was used during SpO₂ measurements. We found a negative correlation between B-line score and minimum SpO₂ (r_s = −0.491; p = 0.002) and mean SpO₂ (r_s = −0.335; p = 0.046). B-line scores were positively correlated with depth (r_s = 0.408; p = 0.013), confirming that extra-vascular lung water is increased with deeper dives. Compared to dives that were asymptomatic, symptomatic dives had a 27% greater B-line score, and both a lower mean and minimum SpO₂ (all p < 0.05). Indeed, a minimum SpO₂ ≤ 95% after a deep dive has a positive predictive value of 29% and a negative predictive value of 100% regarding symptoms. We concluded that elevated B-line scores are associated with reduced SpO₂ after dives, suggesting that SpO₂ via pulse oximetry could be a useful screening tool to detect increased extra-vascular lung water. The practical application is not to diagnose pulmonary edema based on SpO₂ – as pulse oximetry is inexact – rather, to utilize it as a tool to determine which divers require further evaluation before returning to deep freediving.

Percutaneous Closure of Patent Foramen Ovale in the Setting of Pulmonary Embolism (Right-Left Shunt Causing Severe Hypoxia)

A patent foramen ovale (PFO) is well known to cause paradoxical embolism and stroke, but a less appreciated and life-threatening complication can occur when combined with severe pulmonary embolism (PE). Acutely elevated right-sided pressures from right ventricular strain due to PE can lead to right-to-left (R-L) shunting through the PFO and exacerbate hypoxia. We report a case of a 50-year-old female patient with massive PE with further desaturation from R-L shunting from a PFO that benefitted from percutaneous closure of the interartrial communication. Our patient recovered without any complications and had excellent long-term follow-up.

Catheter-directed therapies for pulmonary embolism: considerations for patients with patent foramen ovale

Pulmonary embolism can be fatal, especially in high-risk patients who have contraindications to systemic thrombolysis or surgical embolectomy. For this population, interventionalists can provide catheter-directed therapies, including catheter-directed thrombolysis and thrombectomy, using a wide array of devices. Endovascular treatment of pulmonary embolism shows great promise through fractionated thrombolytic drug delivery, fragmentation, and aspiration mechanisms with thrombectomy devices. Although successful outcomes have been reported after using these treatments, evidence is especially limited in patients with both a patent foramen ovale (PFO) and acute pulmonary embolism. In patients with PFO, it is important to consider whether catheter-directed therapy is appropriate or whether surgical embolectomy should instead be performed. An increased risk of paradoxical embolus in these patients supports the use of diagnostic echocardiography with possible surgical closure of PFO after one episode of pulmonary embolism. Percutaneous PFO closure, which can be performed at the time of catheter-based therapy, theoretically reduces risk of future paradoxical embolization, although more data are needed before making a recommendation for this specific group of patients.

Platypnea-Orthodeoxia Syndrome: Rare or Under-Diagnosed Syndrome? 3 Case Reports and a Literature Review

Platypnea-Orthodeoxia Syndrome (POS) is dyspnea and hypoxemia in the upright position that improves in the supine position. Cardiac POS is predominantly caused by congenital interatrial communications (CIC) paired with changes in the thoracic anatomy, allowing orthostatic right to left cardiac shunting. High suspicion, especially with hypoxemia without significant pulmonary disease, that does not easily correct with supplemental oxygen, should lead the clinician to obtain echocardiographic imaging, documenting right to left shunting, typically through a patent foramen ovale (PFO). Transcatheter closure of the CIC is highly successful in relieving symptoms of dyspnea and resolving hypoxemia in the majority of patients.

Obstructing Chiari Network Facilitating Blood Flow Across a Patent Foramen Ovale Causing Hypoxia

A 36-year-old man with progressive dyspnea and hypoxia was found to have a large, partially fenestrated Chiari network accelerating blood flow through a patent foramen ovale with preservation of an embryonic right-to-left atrial flow pattern. He underwent successful percutaneous patent foramen ovale closure with resolution of his exertional symptoms. (Level of Difficulty: Beginner.)

Pulmonary arterial hypertension populations of special interest: portopulmonary hypertension and pulmonary arterial hypertension associated with congenital heart disease

Guidelines exist for management of pulmonary arterial hypertension (PAH), but information is limited for certain patient subgroups, including adults with portopulmonary hypertension (PoPH) or with PAH associated with congenital heart disease (PAH-CHD). This article discusses screening, clinical management, and prognosis in PoPH and PAH-CHD and, as such, considers the most recent clinical data and expert advice. A multidisciplinary consultation and follow-up by specialists are crucial for management of both PoPH and PAH-CHD, but each condition presents with unique challenges. Development of PoPH most commonly occurs among patients with liver cirrhosis. Initially, patients may be asymptomatic for PoPH and, if untreated, survival with PoPH is generally worse than with idiopathic PAH (IPAH), so early identification with screening is crucial. PoPH can be managed with PAH-specific pharmacological therapy, and resolution is possible in some patients with liver transplantation. With PAH-CHD, survival rates are typically higher than with IPAH but vary across the four subtypes: Eisenmenger syndrome, systemic-to-pulmonary shunts, small cardiac defects, and corrected defects. Screening is also crucial and, in patients who undergo correction of CHD, the presence of PAH should be assessed immediately after repair and throughout their long-term follow-up, with frequency of assessments determined by the patient’s characteristics at the time of correction. Early screening for PAH in patients with portal hypertension or CHD, and multidisciplinary management of PoPH or PAH-CHD are important for the best patient outcomes.

Patent Foramen Ovale and Hypoxemia

Patent foramen ovale (PFO), an embryonic remnant of the fetal circulation, is present in 20-25% of adults. Although recent observational studies and clinical trials have established the link between PFO-mediated right-to-left shunting with cryptogenic stroke and migraine with aura, the role of a PFO in exacerbating hypoxemic medical conditions (ie, sleep apnea, chronic obstructive pulmonary disease, pulmonary hypertension, platypnea-orthodeoxia, pulmonary arteriovenous malformation, high-altitude pulmonary edema, and exercise desaturation) remains less understood. PFO-mediated hypoxemia occurs when deoxygenated venous blood from the right atrium enters and mixes with oxygenated arterial blood in the left atrium. Patients with an intracardiac right-to-left shunt may have profound hypoxemia out of proportion to underlying primary lung disease, even in the presence of normal right-sided pressures. The presence of right-to-left cardiac shunting can exacerbate the degree of hypoxemia in patients with underlying pulmonary disorders. In a subset of these patients, percutaneous PFO closure may result in marked improvement in dyspnea and hypoxemia. This review discusses the association between PFO-mediated right-to-left shunting with medical conditions associated with hypoxemia and explores the role of percutaneous PFO closure in alleviating the hypoxemia.