Foramen ovale perméable et hypoxémie avec ou sans élévation des pressions droites

Case report: Unusual cause of refractory hypoxemia after pacemaker lead extraction

A 59-year-old woman with a history of a pacemaker implanted for III-degree atrioventricular block was admitted due to pocket infection. The atrial and ventricular leads were removed via the right femoral vein using a needle's eye snare. Hypoxemia was observed immediately after the removal of the lead. It was refractory to oxygen therapy. The pulse oxygen saturation (SpO2) showed 89% in the supine position and 77% in the upright position. However, the CTPA and pulmonary perfusion SPECT/CT imaging did not reveal any signs of pulmonary embolism. Pulmonary function tests and chest CT showed normal results. Transthoracic contrast echocardiography revealed a patent foramen ovale (PFO) and a right-to-left intracardiac shunt, no significant tricuspid regurgitation, without any signs of elevated right heart pressure or pulmonary hypertension. Hypoxemia was considered to be associated with the right-to-left shunt through PFO. The condition was relieved by percutaneous closure of the PFO. Refractory hypoxemia resulting from an intracardiac right-to-left shunt following pacemaker lead extraction is a rare but serious complication. Transthoracic contrast echocardiography helps in diagnosis. If the right-to-left intracardiac shunt through PFO persists irreversibly and the associated hypoxemic symptoms are significant, closure of the PFO is necessary. Transesophageal echocardiography also revealed the presence of a left-to-right shunt through PFO during cardiac systole. The closure of the PFO is also necessary to avoid long-term complications, such as chronic pulmonary hypertension and right heart failure.

Risk factors and complications associated with intra-operative or post-operative identification of a PFO in cardiac surgery patients: A cohort study

Introduction

It is unknown whether patent foramen ovale (PFO) reopening in the peri-operative setting of cardiac surgery affects the risk for stroke and post-operative outcomes.

Methods

We performed a single-center, retrospective study based on a prospectively collected database in a tertiary cardiac surgery center. Using logistic regression, we assessed risk factors of PFO finding around surgery and subsequent clinical complications.

Results

Between January 2007 and July 2019, 11034 patients who underwent cardiac surgery in our center were included. A total of 233 patients (2.1%) presented a finding of PFO including 138 per-operative disclosures and 95 post-operative finding for hypoxemia. In the whole cohort, the mean age was 68.4 ± 11.5 years including 73.9% of men. Post-operative PFO finding was associated with more ischemic strokes compared with per-operative finding and control group [7(7.4%) vs. 3(2.2%) vs. 236(2.2), respectively; p = 0.003]. Moreover, patients with post-operative PFO reopening experienced a higher rate of pneumonia, reintubation, and longer length of stay in the ICU. Post-operative reopening of PFO, but not per-operative finding, was independently associated with ischemic strokes {adjusted odds-ratio = 3.5, 95% confidence interval (CI) [1.6-7.8]; p = 0.002}. Other variables associated with stroke incidence included age, mitral valve surgery, and ascending aorta surgery. Per- or post-operative PFO closure was associated with reduced adverse respiratory outcomes and a trend of the lower cerebral ischemic event.

Conclusion

Patent foramen ovale finding incidence in peri-operative cardiac surgery care was rare (2%) but post-operative finding of PFO was associated with a increased risk of ischemic strokes, worsened respiratory outcomes, and prolonged hospitalization.

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.

Flow-driven right-to-left cardiac shunting in a patient with carcinoid heart disease and patent foramen ovale without elevated right atrial pressure: a case report and literature review

Background

Carcinoid heart disease is present in approximately 20% of the patients with carcinoid syndrome and is associated with poor prognosis. It usually manifests with right-sided valvular involvement including tricuspid insufficiency and pulmonary stenosis. Patent foramen ovale (PFO) is present in approximately 50% of the patients with carcinoid heart disease which is twice higher than the general population. Right-to-left shunting through a PFO can occur either due to higher right atrial pressure than left (pressure-driven) or when the venous flow is directed towards the PFO (flow-driven) in the setting of normal intracardiac pressures. We report a rare case of flow-driven right-to-left atrial shunting via PFO in a patient with carcinoid heart disease.

Case summary

A 54-year-old male with a metastatic neuroendocrine tumour to liver presented with progressive shortness of breath for 5 months. Patient was found to be hypoxic with oxygen saturation of 78% and examination revealed a holosystolic murmur. Arterial blood gas showed oxygen tension of 43 mmHg. A transthoracic and transoesophageal echocardiogram showed aneurysmal inter-atrial septum with a PFO, severe tricuspid regurgitation directed anteriorly towards the inter-atrial septum leading to a marked right-to-left shunt. Right heart catheterization showed right atrial pressure of 8 mmHg, mean pulmonary artery pressure of 12 mmHg, and normal oxygen saturations in the right atrium, right ventricle, and pulmonary arteries. The patient then underwent closure of the PFO along with tricuspid valve and pulmonary valve replacement at an experienced cardiovascular surgical centre and has been asymptomatic since.

Conclusion

Right-to-left shunting through a PFO in patients with normal right atrial pressure can be successfully treated with closure of the PFO. Thus, understanding the mechanism of intracardiac shunts is important to accurately diagnose and treat this rare and fatal condition.

Paradoxical worsening of hypoxemia in a patient treated by noninvasive positive pressure ventilation for obesity hypoventilation syndrome with concomitant obstructive sleep apnea: a case report

BACKGROUND

Noninvasive positive pressure ventilation is frequently prescribed to obese patients with obstructive sleep apnea syndrome and obesity hypoventilation syndrome. However, mechanical ventilation with a positive end-expiratory pressure can induce or worsen a right-to-left shunt through a patent foramen ovale associated with systemic hypoxemia. Thus, in obese patients treated with noninvasive positive pressure ventilation, a paradoxical worsening of hypoxemia may reveal the existence of a patent foramen ovale.

CASE PRESENTATION

A 50-year-old African woman was referred to our sleep center for severe obstructive sleep apnea syndrome and obesity hypoventilation syndrome. Because she had alveolar hypoventilation and had failed previous obstructive sleep apnea syndrome therapy, noninvasive positive pressure ventilation was started. In May 2015, she had a normal residual apnea/hypopnea index calculated by the ventilator software with no hypoventilation. Six months later, severe hypoxemia without hypercapnia was noted. Contrast transthoracic echocardiography showed right-to-left shunt through a patent foramen ovale. This finding prompted a decrease in expiratory and inspiratory positive airway pressures, after which the ventilator software recorded a normal residual apnea/hypopnea index and the blood gas values improved.

CONCLUSION

Noninvasive positive pressure ventilation therapy for combined obstructive sleep apnea syndrome and obesity hypoventilation syndrome must be monitored by arterial blood gas measurements, both to reassess the hypercapnia and to look for worsening hypoxemia due to a patent foramen ovale.

[Platypnea, orthodeoxia… A report of two cases]

The plathypnea orthodeoxia syndrome is a rare condition that is characterized by dyspnea and hypoxia that occurs in the upright position and improves with recumbency. The diagnostic is often made tardively and requires the combination of two components: a mechanical one (for example a patent foramen ovale) and a kinetic one (for example COPD). This combination contributes to the blood flow through the communication. The treatment consists of closing the veno-arterial communication (in the case of a patent foramen ovale, the closing of the inter-atrial septum) (Knapper et al, 2014). In the present article, we describe two severe hypoxemic patients suffering from this syndrome. Both cases were associated with an acute pulmonary disease. A review of the literature is performed.

Patent foramen ovale in idiopathic pulmonary arterial hypertension: Long-term risk and morbidity

INTRODUCTION

Little is known about the presence of patent foramen ovale in idiopathic pulmonary arterial hypertension. While there is suspected worsening of hypoxemia confounding assessment and management of pulmonary hypertension, as well as possible increased morbidity from paradoxical emboli, there may be theoretical relief of worsening right-sided pressures by the same mechanism of right-to-left shunting.

METHODS

Retrospective review of consecutive patients diagnosed with idiopathic pulmonary arterial hypertension (WHO Group 1) via right heart catheterization, from 1998 to 2010. All patients also underwent a four chamber transthoracic echocardiogram with agitated saline contrast for the evaluation of patent foramen ovale. Primary clinical data was collected and compared between patients with and without patent foramen ovale along with univariable and multivariable predictors of long term survival.

RESULTS

One hundred and fifty five patients were included in the study, 42 with patent foramen ovale (27%). Patients with patent foramen ovale were younger at pulmonary arterial hypertension diagnosis and trended towards higher right ventricular systolic pressures on echocardiography and mean pulmonary arterial pressures by right heart catheterization. Predictors of mortality included age, diffusing capacity for carbon monoxide, and severe hypoxemia. Only diffusing capacity and age were predictive of mortality after adjustment for a priori covariables.

CONCLUSION

Patent foramen ovale is seen in a quarter of patients with idiopathic pulmonary arterial hypertension and associated with increased prevalence of severe hypoxemia but had no effect on long term survival.

[Practical conduct for patients with a lonely hypoxemia at rest or during exercise]

INTRODUCTION

Hypoxemia is a decrease in blood oxygen partial pressure. This work aims at presenting a practical conduct for patients with a lonely hypoxemia at rest or during exercise, defined by the absence of dyspnea at rest, obvious clinical or radiographic abnormality.

STATE OF THE ART

Diagnostic tools available to the clinician are clinical examination, CT scan, echocardiography, hyperoxia test, trans cranial ultrasound and lung scintigraphy. This work proposes a practical diagnostic approach, with a main role of chest CT.

PERSPECTIVES

Work is underway to determine more precisely the place of echocardiography for the diagnosis of intra or extra cardiac shunts.

CONCLUSIONS

The finding of a lonely hypoxemia requires careful diagnostic approach to quickly rule out potentially serious causes and not to disregard the rare causes.