The incidence of patent foramen ovale in 1,000 consecutive patients. A contrast transesophageal echocardiography study

Diagnosis and treatment of 2 cases with cryptogenic stroke due to patent foramen ovale in children: A case report

RATIONALE

Arterial ischemic stroke is a general term for necrosis of brain tissue due to insufficient blood supply to the brain from various causes. About 30% of these cases are of unknown origin and are known as cryptogenic strokes (CS).

PATIENT CONCERNS

We report 2 female patients, one 5 years and 5 months old and the other 6 years old. Both children had clinical manifestations of CS, and after ruling out other possible etiologies, we finally suspected that CS was associated with patent foramen ovale (PFO).

DIAGNOSES

Case 1 was diagnosed with PFO, paradoxical embolism, and third-degree atrioventricular block, and case 2 was diagnosed with PFO, paradoxical embolism, and refractory mycoplasma pneumonia.

INTERVENTIONS

Case 1 underwent permanent pacemaker placement at the same time as PFO closure. Case 2 underwent conservative anticoagulation with poor therapeutic results and subsequently underwent PFO closure.

OUTCOMES

Patient 1 underwent PFO closure, which resulted in relief of neurologic symptoms and no recurrence of neurologic symptoms after 10 months of follow-up. In case 2, the child's neurologic symptoms improved after PFO closure.

LESSONS

Although most children with PFO do not require targeted interventions, a few cases involving PFO and CS may benefit from closure of the foramen ovale.

Prevalence and characteristics of patent foramen ovale in a sample of Egyptian population: a computed tomography study

BACKGROUND

The reported prevalence of patent foramen ovale (PFO) in the general population is variable. It ranges between 8.6 and 42% according to the population studied and the imaging technique used. We aim to prospectively assess the prevalence and characteristics of PFO and interatrial septum (IAS) abnormalities as well as the related clinical manifestations in a sample of Egyptian population.

RESULTS

This study comprised 1000 patients who were referred for CT coronary angiography (CTCA). Mean age was 52.5 ± 10.9 years. The prevalence of PFO among the studied population was 16.3%; closed PFO (grade I) 44.2%, open PFO (grade II) 50.9%, and open PFO with jet (grade III) 4.9%. Anatomical high-risk PFO features-defined as the presence of at least 2 or more of the following (diameter ≥ 2 mm, length ≥ 10 mm, septal aneurysm "ASA", or redundant septum)-were found in 51.5% of PFOs' population. Other IAS abnormalities as redundant septum (8.6%), ASA (5.3%), Bachmann's bundle (4.5%), microaneurysm (2.6%), and atrial septal defect (ASD) (0.4%) were detected. There was a lower rate of coexistence of ASA with PFO (p = 0.031). Syncope was significantly higher in patients with PFO compared to those without PFO (6.7% vs. 1.6%, p = 0.001). Stroke, transient ischaemic attacks (TIA), and dizziness were similar in both groups. TIA, dizziness, and syncope were significantly higher in patients with IAS abnormalities including PFO compared to those without IAS abnormalities. Syncope was also significantly higher in PFO with high-risk anatomical features compared to those with non-high-risk PFO population (p = 0.02).

CONCLUSION

The prevalence of PFO in our study was approximately 16.3%, almost half of them showed anatomical high-risk features for stroke. Dizziness, syncope and TIA were significantly higher in patients with IAS abnormalities including PFO.

Study design and rationale of COMPETE: Comparison of the effect of medication therapy in alleviating migraine with patent foramen ovale

BACKGROUND

Previous studies have examined the impact of antithrombotic agents on Patent Foramen Ovale (PFO) in relation to migraine. However, differences in effectiveness of different antithrombotic agents and traditional migraine medications are not known.

METHODS/DESIGN

This study is an investigator-initiated, randomized, multicenter, single-masked (outcomes assessor), and active-controlled parallel-group trial (ClinicalTrials.gov Identifier: NCT05546320), with the objective of evaluating the prevention efficacy of antithrombotic agents compared to first-line migraine medication in PFO patients. The trial involves 1,000 migraine patients with a right-to-left shunt at the atrial level, randomized in a 1:1:1:1 fashion to receive either aspirin 300 mg QD, clopidogrel 75 mg QD, rivaroxaban 20 mg QD, or the active-control metoprolol 25 mg BID. The primary efficacy end point is the response rate, defined as a 50% or greater reduction in the average migraine attack days per month or in the average number of migraine attacks per month at 12-week visit compared to baseline.

CONCLUSIONS

The COMPETE trial aims to provide valuable insights into the comparative effectiveness of antithrombotic agents and standard migraine therapies in patients with PFO. This study holds the promise of advancing treatment approaches for individuals having migraines associated with PFO, thus addressing an important gap in current migraine management strategies.

Ignored Role of Paroxysmal Atrial Fibrillation in the Pathophysiology of Cryptogenic Stroke in Patients with Patent Foramen Ovale and Atrial Septal Aneurysm

The association between cryptogenic stroke (CS) and patent foramen ovale (PFO) with or without atrial septal aneurysm (ASA) has been a debate for decades in terms of pathophysiologic processes and clinical courses. This issue has become more interesting and complex, because of the concerns associating the CS with so-called normal variant pathologies of interatrial septum, namely ASA and PFO. While there is an anatomical pathology in the interatrial septum, namely PFO and ASA, the embolic source of stroke is not clearly defined. Moreover, in patients with PFO and CS, the risk of recurrent stroke has also been associated with other PFOunrelated factors, such as hyperlipidemia, body mass index, diabetes mellitus, and hypertension, leading to the difficulty in understanding the pathophysiologic mechanism of CS in patients with PFO and/or ASA. Theoretically, the embolic source of cryptogenic stroke in which PFO and/or ASA has been involved can be categorized into three different anatomical locations, namely PFO tissue and/or ASA tissue itself, right or left atrial chambers, and venous vascular territory distal to the right atrium, i.e., inferior vena cava and lower extremity venous system. However, the possible role of paroxysmal atrial fibrillation associated with PFO and/or ASA as a source of cryptogenic stroke has never been mentioned clearly in the literature. This review aims to explain the association of cryptogenic stroke with PFO and/or ASA in a comprehensive manner, including anatomical, clinical, and mechanistic aspects. The potential role of paroxysmal atrial fibrillation and its contribution to clinical course have been also discussed in a hypothetical manner to elucidate the pathophysiology of CS and support further treatment modalities.

Disappearance of aura symptoms in patients with hemiplegic migraine after patent foramen ovale closure: a case report and literature review

Hemiplegic migraine (HM) can cause significant functional impairment and negatively affect the quality of life of affected individuals. Emerging evidence suggests an association between migraines and congenital patent foramen ovale (PFO), which is a small opening between the atria of the heart that normally closes shortly after birth. This report describes a 34 years-old woman with sporadic hemiplegic migraine (SHM) who was diagnosed with PFO. Following percutaneous PFO closure, her hemiplegic symptoms disappeared, but her headache exacerbated. After 3 years of follow-up, her headache severity gradually reduced, and the frequency remained consistent at 2-3 times per year with no aura symptoms. This case highlights the dissociation between the resolution of hemiplegic symptoms and the persistence of headaches after PFO closure in sporadic HM. Patients with HM may experience changes in aura symptoms and headache severity after PFO closure. Before performing PFO closure in patients with hemiplegic migraine, the indications should be thoroughly understood.

Iatrogenic air embolism: pathoanatomy, thromboinflammation, endotheliopathy, and therapies

Iatrogenic vascular air embolism is a relatively infrequent event but is associated with significant morbidity and mortality. These emboli can arise in many clinical settings such as neurosurgery, cardiac surgery, and liver transplantation, but more recently, endoscopy, hemodialysis, thoracentesis, tissue biopsy, angiography, and central and peripheral venous access and removal have overtaken surgery and trauma as significant causes of vascular air embolism. The true incidence may be greater since many of these air emboli are asymptomatic and frequently go undiagnosed or unreported. Due to the rarity of vascular air embolism and because of the many manifestations, diagnoses can be difficult and require immediate therapeutic intervention. An iatrogenic air embolism can result in both venous and arterial emboli whose anatomic locations dictate the clinical course. Most clinically significant iatrogenic air emboli are caused by arterial obstruction of small vessels because the pulmonary gas exchange filters the more frequent, smaller volume bubbles that gain access to the venous circulation. However, there is a subset of patients with venous air emboli caused by larger volumes of air who present with more protean manifestations. There have been significant gains in the understanding of the interactions of fluid dynamics, hemostasis, and inflammation caused by air emboli due to in vitro and in vivo studies on flow dynamics of bubbles in small vessels. Intensive research regarding the thromboinflammatory changes at the level of the endothelium has been described recently. The obstruction of vessels by air emboli causes immediate pathoanatomic and immunologic and thromboinflammatory responses at the level of the endothelium. In this review, we describe those immunologic and thromboinflammatory responses at the level of the endothelium as well as evaluate traditional and novel forms of therapy for this rare and often unrecognized clinical condition.

Neurologic Complications of Cardiac and Pulmonary Disease

OBJECTIVE

The heart and lungs work as a functional unit through a complex interplay. The cardiorespiratory system is responsible for the delivery of oxygen and energy substrates to the brain. Therefore, diseases of the heart and lungs can lead to various neurologic illnesses. This article reviews various cardiac and pulmonary pathologies that can lead to neurologic injury and discusses the relevant pathophysiologic mechanisms.

LATEST DEVELOPMENTS

We have lived through unprecedented times over the past 3 years with the emergence and rapid spread of the COVID-19 pandemic. Given the effects of COVID-19 on the lungs and heart, an increased incidence of hypoxic-ischemic brain injury and stroke associated with cardiorespiratory pathologies has been observed. Newer evidence has questioned the benefit of induced hypothermia in patients with out-of-hospital cardiac arrest. Further, global collaborative initiatives such as the Curing Coma Campaign are underway with the goal of improving the care of patients with coma and disorders of consciousness, including those resulting from cardiac and pulmonary pathologies.

ESSENTIAL POINTS

The neurologic complications of cardiorespiratory disorders are common and present in various forms such as stroke or hypoxic and anoxic injury related to cardiac or respiratory failure. With the emergence of the COVID-19 pandemic, neurologic complications have increased in recent years. Given the intimate and interdependent dynamics of the heart, lungs, and brain, it is crucial for neurologists to be aware of the interplay between these organs.

Effect of sex, age and body measurements on heart weight, atrial, ventricular, valvular and sub-epicardial fat measurements of the normal heart

AIMS

Descriptive morphological studies of the normal heart are lacking. Previous autopsy studies have focused mainly on heart weight. We characterize the normal heart by providing normal dimensions of the atria, ventricles, valves and sub-epicardial fat, comparing the findings in terms of sex, age and body measurements.

METHODS

From 3602 referrals to our cardiovascular pathology unit, pathological criteria used for the classification of a morphologically normal heart were a weight of below 500 grams in males, and below 400 grams in females. Diseased hearts were excluded on anatomical and histological evaluation.

RESULTS

We diagnosed 1062 morphologically normal hearts. Mean age at death was 34±12, with a male predominance (701, 66%). Age was similar in females and males (35±13 vs 34±12). Females had a significantly lower heart weight (285±55 vs 374±64). Sex was an independent predictor of most measurements. The atrial and ventricular cavities were significantly larger in males. All ventricular measurements of muscle thickness were larger in males. All valvular circumferences were larger in males. In contrast, sub-epicardial fat was significantly thicker in females in 6 of 7 regions. This is the first study to provide a calculator to give expected values according to sex, age, height and weight.

CONCLUSIONS

Major differences between the sexes exist in the morphologically normal heart. These variations should be considered when assessing cardiac structure in imaging for risk stratification and diagnosis in the cardiomyopathies, as well as in treatment outcomes.

Tricuspid-regurgitation-mediated flow-driven right-to-left cardiac shunting caused systemic hypoxemia in a patient with patent foramen ovale without elevated right atrial pressure

The prevalence of patent foramen ovale (PFO) is 20-25% among adults. The role of right-to-left shunting through the PFO in systemic hypoxemia remains poorly understood. Right-to-left shunting through the PFO can occur either due to elevated right atrial pressure (pressure-driven) or directed venous flow toward the PFO (flow-driven). Herein, we report a rare case of flow-driven right-to-left shunting via the PFO in a patient with traumatic tricuspid regurgitation. A 45-year-old Chinese woman was admitted due to progressive dyspnea for 3 years, presenting with cyanosis and digital clubbing. She was hypoxic, with an oxygen saturation of 83% on room air, and arterial blood gas showed an oxygen tension of 53 mmHg. Echocardiography showed severe tricuspid regurgitation with ruptured chordae tendinea, causing regurgitant jet flow directed toward the interatrial septum, leading to intermittent right-to-left shunting between the septa primum and secundum. Swan-Ganz catheterization revealed normal-high right atrial pressure and excluded pulmonary hypertension. The patient underwent tricuspid valve repair and PFO closure. Her oxygen saturation returned to 95% and her symptoms resolved. Right-to-left shunting through the PFO could cause systemic hypoxemia via a flow-driven mechanism, occasionally manifesting as cyanosis and clubbing digits. PFO closure and treatment of underlying disease are effective in improving hypoxemia.

Increased incidence of mitral valve prolapse in children with pectus chest wall deformity

BACKGROUND

Pectus anomalies constitute 95% of chest anomalies. Pectus carinatum (PC) and excavatum (PE) are often asymptomatic in childhood. However, symptoms and signs such as chest pain, dyspnea, and mitral valve prolapse (MVP) can be seen in pectus anomalies. Demographic characteristics and accompanying cardiac signs in children with pectus deformity were investigated.

METHODS

In this study, the clinical findings for children with pectus deformity, and the incidence of MVP and other concomitant heart diseases detected in echocardiographic examinations were evaluated.

RESULTS

Eighty-two children with PE, 27 with PC, and 107 healthy children were included in this study. In the echocardiographic examination of PE, PC patients, and healthy children, MVP was detected with frequencies of 25%, 33%, and 2% respectively.

CONCLUSIONS

The study showed that pectus anomalies were associated with an increased incidence of MVP. All patients with pectus deformity should therefore undergo a screening echocardiogram in adolescence to assess for the presence of MVP.

Left atrial septal pouch in a six-year-old child: echocardiographic and magnetic resonance view

In a 6-year-old child patient, transthoracic echocardiography revealed a large saccular structure (with anechogenic content) in the left atrium, near the fossa ovalis, and diagnosis of the left atrial septal pouch was made. The left atrial septal pouch is a kangaroo pouch-like structure on the left side of the interatrial septum, opened into the left atrial cavity without a connection between the left and right atria. It occurs when the foramen ovale is absent but the septum primum and septum secundum are only partially fused. The left atrial septal pouch is believed to be present in 47% of population. In many cases, the pocket on the atrial septum is small and it could not be detected by transthoracic echocardiography. Our description is uncommon because we diagnosed a very large septal pouch. Based on our knowledge, this is the youngest reported case of the left atrial septal pouch and the longest follow-up described in this type of congenital heart malformation.

The presence of a large patent foramen ovale reduces acute and chronic success in atrial fibrillation ablation

PURPOSE

In this study, we analyzed PFO implications in atrial fibrillation (AF) ablation.

METHODS

Six hundred and twenty-five consecutive patients with AF undergoing PV isolation were included. We considered that a large and/or compliant PFO was present if the catheters advanced gently into the LA without puncturing the septum. Atrial tachyarrhythmias after the 3-month blanking period were classified as a recurrence.

RESULTS

Out of the 625 patients included, 36 (5.8%) were found to have PFO. No significant differences were observed in the clinical characteristics of patients with PFO compared with patients without PFO. Nevertheless, patients with PFO had lower acute success in PV isolation compared with patients without PFO (98.2% vs. 88.5%; p = 0.006) even after adjusting for age, sex, type of AF, LA area, cardiomyopathy, time from AF diagnosis to the ablation, and ablation technique (odds ratio: 0.1; 95% confidence interval (CI): 0.02-0.9; p = 0.039). In 546 patients followed more than 6 months, the recurrence rate of any atrial tachyarrhythmia after 18.6 ± 11.9 months was significantly higher in patients with PFO compared with patients without PFO (41.9 vs. 70%; p = 0.012). This difference remained significant after adjusting for age, sex, type of AF, LA area, cardiomyopathy, time from AF diagnosis to the ablation, and ablation technique (hazard ratio: 1.9; 95% CI: 1.1-3.3; p = 0.015).

CONCLUSIONS

The presence of a large and/or compliant PFO is an independent factor for PV isolation failure and arrhythmia recurrence rate after the ablation.

[Intraoperative transesophageal echocardiography for emergency diagnostics in noncardiac surgery patients]

Due to the development of compact and mobile devices, transesophageal echocardiography (TEE) is now being used as one important point-of-care diagnostic method in emergency rooms, intensive care units and operating rooms. In the first part of this advanced training series, general aspects of the examination method and the procedure as well as indications and contraindications were outlined. In addition, an overview of application areas beyond cardiac surgery in which TEE can be used to monitor the patient or to assist with the operative procedure was provided. In the second part, the main findings during intraoperative TEE in the event of hemodynamic instability or unexplained hypoxemia are presented. A shortened emergency examination as proposed by Reeves et al. is outlined. The article concludes with an outlook on semiautomatic interpretation software and computer-aided image acquisition.

Indirect measurement of absolute cardiac output during exercise in simulated altered gravity is highly dependent on the method

PURPOSE

Altered gravity environments introduce cardiovascular changes that may require continuous hemodynamic monitoring in both spaceflight and terrestrial analogs. Conditions in such environments are often prohibitive to direct/invasive methods and therefore, indirect measurement techniques must be used. This study compares two common cardiac measurement techniques used in the human spaceflight domain, pulse contour analysis (PCA-Nexfin) and inert gas rebreathing (IGR-Innocor), in subjects completing ergometer exercise under altered gravity conditions simulated using a tilt paradigm.

METHODS

Seven subjects were tilted to three different angles representing Martian, Lunar, and microgravity conditions in the rostrocaudal direction. They completed a 36-min submaximal cardiovascular exercise protocol in each condition. Hemodynamics were continuously monitored using Nexfin and Innocor.

RESULTS

Linear mixed-effects models revealed a significant bias of [Formula: see text] ml ([Formula: see text]) in stroke volume and [Formula: see text] l/min ([Formula: see text]) in cardiac output, with Nexfin measuring greater than Innocor in both variables. These values are in agreement with a Bland-Altman analysis. The correlation of stroke volume and cardiac output measurements between Nexfin and Innocor were [Formula: see text] ([Formula: see text]) and [Formula: see text] ([Formula: see text]) respectively.

CONCLUSION

There is a poor agreement in absolute stroke volume and cardiac output values between measurement via PCA (Nexfin) and IGR (Innocor) in subjects who are exercising in simulated altered gravity environments. These results suggest that the chosen measurement method and device greatly impacts absolute measurements of cardiac output. However, there is a good level of agreement between the two devices when measuring relative changes. Either of these devices seem adequate to capture cardiac changes, but should not be solely relied upon for accurate measurement of absolute cardiac output.

Multiple simultaneous embolic cerebral infarctions 11 months after COVID-19

BACKGROUND

The coronavirus disease (COVID-19) pandemic has led to an unprecedented worldwide burden of disease. However, little is known of the longer-term implications and consequences of COVID-19. One of these may be a COVID-19 associated coagulopathy that can present as a venous thromboembolism (VTE) and further, as multiple paradoxical cerebral emboli.

CASE PRESENTATION

A 51 year old man presented to the emergency department with multiple simultaneous embolic cerebral infarctions 11 months after mild COVID-19. In the subacute phase of the COVID-19 illness the patient developed increasing shortness of breath and was found to have an elevated D-dimer and multiple bilateral segmental pulmonary emboli. He was subsequently treated with 3 months of anticoagulation for a provoked VTE. The patient then presented 11 months after the initial COVID-19 diagnosis with multiple simultaneous cerebral infarctions where no traditional underlying stroke etiology was determined. A patent foramen ovale (PFO) and an elevated D-dimer were found suggesting a paradoxical thromboembolic event due to an underlying coagulopathy.

CONCLUSIONS

This case report highlights the one of the potentially more serious complications of long-term COVID-19 where VTE due to a persistent coagulopathy is seen almost a year after the initial illness. Due to the highly prevalent nature of PFO in the general population, VTE due to COVID-19 associated coagulopathy could lead to ischemic stroke. This case report highlights the possibility for an underlying COVID-19 associated coagulopathy which may persist for many months and beyond the initial illness.

In Vivo and In Vitro Genetic Models of Congenital Heart Disease

Congenital cardiovascular malformations represent the most common type of birth defect and encompass a spectrum of anomalies that range from mild to severe. The etiology of congenital heart disease (CHD) is becoming increasingly defined based on prior epidemiologic studies that supported the importance of genetic contributors and technological advances in human genome analysis. These have led to the discovery of a growing number of disease-contributing genetic abnormalities in individuals affected by CHD. The ever-growing population of adult CHD survivors, which are the result of reductions in mortality from CHD during childhood, and this newfound genetic knowledge have led to important questions regarding recurrence risks, the mechanisms by which these defects occur, the potential for novel approaches for prevention, and the prediction of long-term cardiovascular morbidity in adult CHD survivors. Here, we will review the current status of genetic models that accurately model human CHD as they provide an important tool to answer these questions and test novel therapeutic strategies.

Heart failure and atrial fibrillation in patients with an interatrial shunt

OBJECTIVE

Congenital interatrial shunt can unload the left atrium (LA) and may lower the risk of new-onset heart failure (HF) or atrial fibrillation (AF). We evaluated the risk of new-onset HF or AF in patients with and without interatrial shunt.

METHODS

We enrolled 2660 consecutive patients with acute stroke or transient ischemic attack (TIA) who underwent transesophageal echocardiography at Seoul National University Bundang Hospital from January 1, 2006 to December 31, 2018. The primary outcomes were 10-year new-onset HF, new-onset AF, and new-onset HF or AF composite.

RESULTS

Overall, 466 (17.5%) patients with an interatrial shunt had smaller E velocity (0.66 ± 0.21 vs. 0.69 ± 0.22 m/s, P = 0.037) and smaller E/e' (9.1 ± 4.0 vs. 10.0 ± 5.0, P = 0.001) than 2194 (82.5%) patients without an interatrial shunt. The 10-year incidence of AF, HF, and AF or HF composite was lower in patients with an interatrial shunt (10-year AF, 11.2 vs. 17.8%, P < 0.001; 10-year HF, 6.2 vs. 10.4%, P = 0.005; 10-year AF or HF composite, 16.5 vs. 23.4%, P = 0.001). In multivariable analysis, the presence of an interatrial shunt was associated with a 38% (HR 0.62, 95% CI 0.40-0.96), 40% (HR 0.60; 95% CI 0.39-0.93), and 26% (HR 0.74; 95% CI 0.57-0.96) reduced risk for new-onset HF, AF, and new-onset HF or AF composite, respectively.

CONCLUSION

In patients with interatrial shunt, the risk of AF and HF was lower. Interatrial shunt may be beneficial, and the closure of an interatrial shunt should be performed only in carefully selected patients. An interatrial shunt can unload the left atrium. In patients with stroke or TIA, the presence of an interatrial shunt was associated with a reduced risk for new-onset HF and AF. AF atrial fibrillation, HF heart failure, HR hazard ratio, LA left atrium.

The Correlation Between Migraine and Patent Foramen Ovale

Background: Migraine is a widespread neurological disorder. The patent foramen ovale (PFO) is a remnant of the fetal circulation. Multiple studies suggest that migraine is more prevalent in subjects with PFO and vice versa. It is unclear if there is a causal relationship or simply a co-existence of these two conditions. Furthermore, the treatment of migraine with percutaneous closure PFO remains controversial.

Methods: We reviewed studies pertaining to the relationship between PFO and migraine as well as the effects of treatments on migraine attacks.

Results: We briefly summarized potential pathophysiological mechanisms of migraine, and elaborated on migraine type, frequency, and clinical symptoms of migraine with PFO and the clinical features of PFO with migraine. We also addressed the effects of PFO closure on migraine attacks.

Conclusion: The evidence supports a “dose-response” relationship between migraine and PFO although more work needs to be done in terms of patient selection as well as the inclusion of an antiplatelet control group for PFO closure interventions to uncover possible beneficial results in clinical trials.

A New Era in Zero X-ray Ablation

In this article, the authors focus on the importance of the zero X-ray ablation approach in electrophysiology. Radiation exposure related to conventional transcatheter ablation carries small but non-negligible stochastic and deterministic effects on health. Non-fluoroscopic mapping systems can significantly reduce, or even completely avoid, radiological exposure. The zero X-ray approach determines potential clinical benefits in terms of reduction of ionising radiation exposure, as well as safe technical advantages. The use of this method can result in similar outcomes when compared to the conventional fluoroscopic technique. These results are achieved without altering the duration, or compromising the effectiveness and safety, of the procedure. The zero X-ray ablation approach is a feasible and safe alternative to fluoroscopy, which is often only used in selected cases for troubleshooting. The non-fluoroscopic approach is considered a milestone for cancer prevention in ablation procedures.

Severe hypoxia caused by ascending aorta elongation due to aortic arch aneurysm

Patent foramen ovale, sometimes associated with clinical manifestation, is frequently detected during adulthood. Platypnea-orthodeoxia syndrome, a rare condition characterized by dyspnea and hypoxia aggravated in the upright position, is caused by a right-to-left shunt across a patent foramen ovale. We present a case of a 73-year-old man with severe hypoxia caused by an aortic arch aneurysm that distorted the atrial septal geometry and worsened the right-to-left shunt. Clinicians should consider a right-to-left shunt via a patent foramen ovale when an aortic arch aneurysm causes counterclockwise cardiac rotation. Furthermore, the alveolar-arterial oxygen difference can be used to diagnose platypnea-orthodeoxia syndrome.

Cardiovascular shunting in vertebrates: a practical integration of competing hypotheses

This review explores the long-standing question: 'Why do cardiovascular shunts occur?' An historical perspective is provided on previous research into cardiac shunts in vertebrates that continues to shape current views. Cardiac shunts and when they occur is then described for vertebrates. Nearly 20 different functional reasons have been proposed as specific causes of shunts, ranging from energy conservation to improved gas exchange, and including a plethora of functions related to thermoregulation, digestion and haemodynamics. It has even been suggested that shunts are merely an evolutionary or developmental relic. Having considered the various hypotheses involving cardiovascular shunting in vertebrates, this review then takes a non-traditional approach. Rather than attempting to identify the single 'correct' reason for the occurrence of shunts, we advance a more holistic, integrative approach that embraces multiple, non-exclusive suites of proposed causes for shunts, and indicates how these varied functions might at least co-exist, if not actually support each other as shunts serve multiple, concurrent physiological functions. It is argued that deposing the 'monolithic' view of shunting leads to a more nuanced view of vertebrate cardiovascular systems. This review concludes by suggesting new paradigms for testing the function(s) of shunts, including experimentally placing organ systems into conflict in terms of their perfusion needs, reducing sources of variation in physiological experiments, measuring possible compensatory responses to shunt ablation, moving experiments from the laboratory to the field, and using cladistics-related approaches in the choice of experimental animals.

Right-to-left shunts in lowlanders with COPD traveling to altitude: a randomized controlled trial with dexamethasone

Right-to-left shunts (RLS) are prevalent in patients with chronic obstructive pulmonary disease (COPD) and might exaggerate oxygen desaturation, especially at altitude. The aim of this study was to describe the prevalence of RLS in patients with COPD traveling to altitude and the effect of preventive dexamethasone. Lowlanders with COPD [Global Initiative for Chronic Obstructive Lung Disease (GOLD) grades 1-2, oxygen saturation assessed by pulse oximetry (SpO2) >92%] were randomized to dexamethasone (4 mg bid) or placebo starting 24 h before ascent from 760 m and while staying at 3,100 m for 48 h. Saline-contrast echocardiography was performed at 760 m and after the first night at altitude. Of 87 patients (81 men, 6 women; mean ± SD age 57 ± 9 yr, forced expiratory volume in 1 s 89 ± 22% pred, SpO2 95 ± 2%), 39 were assigned to placebo and 48 to dexamethasone. In the placebo group, 19 patients (49%) had RLS, of which 13 were intracardiac. In the dexamethasone group 23 patients (48%) had RLS, of which 11 were intracardiac (P = 1.0 vs. dexamethasone). Eleven patients receiving placebo and 13 receiving dexamethasone developed new RLS at altitude (P = 0.011 for both changes, P = 0.411 between groups). RLS prevalence at 3,100 m was 30 (77%) in the placebo and 36 (75%) in the dexamethasone group (P = not significant). Development of RLS at altitude could be predicted at lowland by a higher resting pulmonary artery pressure, a lower arterial partial pressure of oxygen, and a greater oxygen desaturation during exercise but not by treatment allocation. Almost half of lowlanders with COPD revealed RLS near sea level, and this proportion significantly increased to about three-fourths when traveling to 3,100 m irrespective of dexamethasone prophylaxis.NEW & NOTEWORTHY The prevalence of intracardiac and intrapulmonary right-to-left shunts (RLS) at altitude in patients with chronic obstructive pulmonary disease (COPD) has not been studied so far. In a large cohort of patients with moderate COPD, our randomized trial showed that the prevalence of RLS increased from 48% at 760 m to 75% at 3,100 m in patients taking placebo. Preventive treatment with dexamethasone did not significantly reduce the altitude-induced recruitment of RLS. Development of RLS at 3,100 m could be predicted at 760 m by a higher resting pulmonary artery pressure and arterial partial pressure of oxygen and a more pronounced oxygen desaturation during exercise. Dexamethasone did not modify the RLS prevalence at 3,100 m.

High Altitude Pulmonary Edema in Children: A Single Referral Center Evaluation

OBJECTIVE

To describe the clinical features of children who presented to Children's Hospital Colorado (CHCO) with high-altitude pulmonary edema (HAPE).

STUDY DESIGN

We performed a retrospective chart review in children discharged from CHCO (an elevation of 1668 m) with a clinical diagnosis of HAPE and a chest radiograph consistent with noncardiogenic pulmonary edema. Descriptive statistics were used to describe the demographics, presentations, and treatment strategies.

RESULTS

From 2004 to 2014, 50 children presented to CHCO who were found to have a clinical diagnosis of HAPE and a chest radiograph consistent with noncardiogenic pulmonary edema. Most (72%) patients were male, and most (60%) of the children in the study were diagnosed with classic HAPE, 38% with re-entry HAPE, and 2% with high altitude resident pulmonary edema. Elevation at symptom presentation ranged from 1840 to 3536 m. Patients were treated with a variety of medications, including diuretics, steroids, and antibiotics. Four patients were newly diagnosed with structural heart findings: 2 patients with patent foramen ovale and 2 with atrial septal defects. Eleven patients had findings consistent with pulmonary hypertension at the time of echocardiography.

CONCLUSIONS

HAPE symptoms may develop below 2500 m, so providers should not rule out HAPE based on elevation alone. Structural heart findings and pulmonary hypertension are associated with HAPE susceptibility and their presence may inform treatment. Inappropriate use of antibiotics and diuretics in children with HAPE suggest that further education of providers is warranted.

Interaction of cardiac implantable electronic device and patent foramen ovale in ischemic stroke: A case-only study

BACKGROUND

Cardiovascular implantable electronic device (CIED) leads are a nidus for right atrial thrombi. Right-to-left thromboembolism across a patent foramen ovale (PFO) is a putative mechanism for ischemic stroke and PFO has been associated with stroke. We used a novel unbiased case-only study design to assess the effect modification of PFO-associated ischemic stroke risk by presence of CIED. We hypothesized that presence of CIED, as a nidus for right atrial thrombus formation, magnifies the PFO-ischemic stroke relationship; therefore, among hospitalized ischemic stroke patients we would find a higher prevalence of CIED in patients with PFO.

METHODS

We included consecutive first ischemic stroke patients admitted to our hospital from 2006 to 2015, who were enrolled in a prospectively maintained stroke registry. PFO was ascertained from documentation on echocardiography, and presence of CIED at time of stroke was determined from chest radiography reports at or prior to hospitalization. We measured distributions of CIED within PFO and control groups and used Fisher's exact test to evaluate the PFO-CIED association among ischemic stroke patients.

RESULTS

We included 7089 patients (age: 64.5 ± 14.9 years, 51% female). Echocardiography diagnosed PFO in 760 (10.7%) patients and CIED was reported on chest radiography in 752 (10.6%) patients. Prevalence of CIED was lower in the PFO (61/760, 8.0%) compared to control group (691/6329, 10.9%), P = 0.015.

CONCLUSION

Among admitted ischemic stroke patients, we did not find a higher prevalence of CIED in patients with PFO compared to controls. Therefore, in the underlying source population, the presence of CIED did not increase the PFO-associated ischemic stroke risk.

Tilting the balance: hemidiaphragm paralysis leading to right to left cardiac shunt

Patent foramen ovale (PFO) is a congenital abnormality present in 25%-30% of healthy adults and rarely leads to any sequelae. ^{1 2} It is associated with a left-to-right shunt which usually does not lead to any haemodynamic compromise. Occasionally, the shunt can get reversed; that is, right-to-left shunt occurs due to worsening pulmonary hypertension and can lead to persistent hypoxia. It is rare for the shunt reversal to happen in the absence of pulmonary hypertension. Here, we present an exceedingly rare case in a 61-year-old man presenting with hypoxia, was found to have shunt reversal due to unilateral diaphragmatic paralysis. He was successfully treated with PFO closure. The purpose of this report is to consider rare possibilities of PFO shunt reversal when the right-sided heart pressure is normal and to highlight that a simple chest X-ray can be a clue to the diagnosis.

Contrast Transthoracic Echocardiography Using 50% Glucose as a Contrast Agent for Screening of a Patent Foramen Ovale

A patent foramen ovale (PFO) is considered a risk factor for neurologic events. The goal of the study described here was to assess the feasibility, advantages, diagnostic sensitivity and accuracy of contrast transthoracic echocardiography examination (cTTE) using 50% glucose as a contrast agent in comparison with the use of agitated saline as contrast to screen for PFO. In our study, we found that the peak time, effective duration and duration of microbubbles produced by 50% glucose were all longer than those produced by the physiologic saline. The sensitivities for detection of PFO with cTTE using physiologic saline and 50% glucose as contrast were 83% (20/24) and 100% (24/24), respectively. TEE suggested a PFO in 24 patients in two groups. Use of 50% glucose as a contrast agent in cTTE examination enables ultrasound technicians to easily observe the right-to-left shunt across the PFO. However, the sensitivities for detection of PFO with cTTE using 50% glucose did not statistically significantly differ from those for physiologic saline.

Patent foramen ovale and atrial fibrillation as causes of cryptogenic stroke: is treatment with surgery superior to device closure and anticoagulation? A review of the literature

Closure of persistent foramen ovale (PFO) to avoid cryptogenic strokes is performed globally with enthusiasm but lacks prove of efficacy. We present a 79-year-old man who had had a PFO device introduced nine years previously because of cryptogenic strokes presenting as syncopes. The patient was referred from his general practitioner with two new syncopes. Transthoracic echocardiography revealed no cardiac causes of embolism. Transesophageal echocardiography (TEE) revealed a misplaced device like an umbrella in a storm, but no septum defects. Holter revealed seconds-long episodes of atrial fibrillation (AF). The patient was successfully treated with anticoagulation.

A literature review showed that: (i) the efficacy of PFO closure devices has not been proven in any trial, but was demonstrated in a meta-analysis comparing three different devices; (ii) PFO devices are rarely controlled by TEE during or after insertion; (iii) residual shunts are detected in up to 45% of cases; (iv) there is an increased rate of post-arrhythmic complications; (v) the risk of AF in congenital heart disease increases with increasing age, with a 13% risk of transient ischemic attacks and stroke; and (vi) surgical treatment of PFO was found to have a 4.1% risk of complications including stroke.

The question to be asked is whether device closure of PFO should be avoided, considering that PFO is a congenital heart defect with risks of AF and (cryptogenic) stroke? Heart surgery should be a treatment option for symptomatic PFO.

Effect of Patent Foramen Ovale in Patients With Pulmonary Hypertension

Septostomy reduces right ventricular (RV) workload at the expense of hypoxemia in patients with advanced pulmonary hypertension (PH). A patent foramen ovale (PFO) may serve as a "natural" septostomy, but the incidence and impact of a PFO in PH remains uncertain. We prospectively examined echocardiograms in 404 PH patients referred for initial hemodynamic assessment. Patients included had saline bubble injection and if negative repeatinjection after Valsalva maneuver. Echocardiographic and hemodynamic data were examined. Survival was modeled using Kaplan-Meier method. Eisenmenger syndrome or known atrial shunts other than PFO were excluded: 292 patients met entry criteria. A PFO was identified in 16.8% of the entire cohort, 22.9% of pulmonary arterial hypertension (PAH) patients, and 8.6% of Dana Point group 2 PH patients. Right atrial to pulmonary capillary wedge pressure difference was lowest in the latter group (-7.9 ± 7.1 vs -1.7 ± 5.5 mm Hg for all others, p <0.01). Patients with a PFO were younger (53.9 vs 58.6 years, p = 0.02). A PFO was more often present with moderately or severely dilated (p = 0.01) or dysfunctional (p = 0.03) RVs. Six year survival was unchanged by PFO presence for all patients, including those with PAH. Proportional hazards analysis found only age and functional class independently predicted survival (p <0.01). A PFO is identified less often in Dana Point group 2 PH, likely due to inability of Valsalva maneuver to overcome right atrial to pulmonary capillary wedge pressure difference. In conclusion, the incidence of a PFO in the PH population increases with more dilated and dysfunctional RVs, suggesting that the PFO may be stretched open rather than congenital. The presence of a PFO does not impact survival in PH or PAH.

Inspiratory and expiratory resistance cause right-to-left bubble passage through the foramen ovale

A patent foramen ovale (PFO) is linked to increased risk of decompression illness in divers. One theory is that venous gas emboli crossing the PFO can be minimized by avoiding lifting, straining and Valsalva maneuvers. Alternatively, we hypothesized that mild increases in external inspiratory and expiratory resistance, similar to that provided by a SCUBA regulator, recruit the PFO. Nine healthy adults with a Valsalva-proven PFO completed three randomized trials (inspiratory, expiratory, and combined external loading) with six levels of increasing external resistance (2-20 cmH2 O/L/sec). An agitated saline contrast echocardiogram was performed at each level to determine foramen ovale patency. Contrary to our hypothesis, there was no relationship between the number of subjects recruiting their PFO and the level of external resistance. In fact, at least 50% of participants recruited their PFO during 14 of 18 trials and there was no difference between the combined inspiratory, expiratory, or combined external resistance trials (P > 0.05). We further examined the relationship between PFO recruitment and intrathoracic pressure, estimated from esophageal pressure. Esophageal pressure was not different between participants with and without a recruited PFO. Intrasubject variability was the most important predictor of PFO patency, suggesting that some individuals are more likely to recruit their PFO in the face of even mild external resistance. Right-to-left bubble passage through the PFO occurs in conditions that are physiologically relevant to divers. Transthoracic echocardiography with mild external breathing resistance may be a tool to identify divers that are at risk of PFO-related decompression illness.

Recognizing and reacting to complications of trans-septal puncture

INTRODUCTION

The transseptal puncture (TSP) enables access to the left heart, through the fossa ovalis (FO), both in electrophysiology and in cardiac interventional procedures. TSP is usually safe in experienced hands. Sometimes TSP can be technically demanding and carries the risk of severe complications in approximately 1%. While performing a TSP, every effort should be taken in order to avoid complications. In the event of complications, prompt recognition and reaction are essential and a combined 'heart-team' management may be the most effective approach. Areas covered: Main TSP-related complications are cardiac tamponade, aortic root puncture, embolic stroke, transient ST elevation of inferior leads and iatrogenic atrial septal defect. A challenging TSP may be expected in presence of difficult IAS-FO anatomies, previous TSP, IAS occluder device and previous IAS surgical repair. Use of echo imaging and special needles (ie., radiofrequency needle and J-shaped guidewire) may avoid TSP-related complications in difficult settings. Expert commentary: Some tools are available to help minimize the risks of TSP. However, their availability might be limited. To increase safety of TSP, an adequate training of physicians, identification of patients in whom it might be difficult and a prompt recognition of complications seem to be the most important background.

Symptomatic Patent Foramen Ovale with Hemidiaphragm Paralysis

Dyspnea accounts for more than one-fourth of the hospital admissions from Emergency Department. Chronic conditions such as Chronic Obstructive Pulmonary Disease, Congestive Heart Failure, and Asthma are being common etiologies. Less common etiologies include conditions such as valvular heart disease, pulmonary embolism, and right-to-left shunt (RLS) from patent foramen ovale (PFO). PFO is present in estimated 20–30% of the population, mostly a benign condition. RLS via PFO usually occurs when right atrium pressure exceeds left atrium pressure. RLS can also occur in absence of higher right atrium pressure. We report one such case that highlights the importance of high clinical suspicion, thorough evaluation, and percutaneous closure of the PFO leading to significant improvement in the symptoms.

Diving with pre-existing medical conditions

INTRODUCTION

This is the second report based on a survey of Divers Alert Network Asia-Pacific (DAN AP) members who dive with cardiovascular and respiratory conditions and diabetes. It examines the medical management of the divers' conditions, any diving modifications used to mitigate the risk and outcomes.

METHODOLOGY

An online cross-sectional survey was sent to 833 divers who had declared a targeted medical condition when applying for DAN AP membership between July 2009 and August 2013.

RESULTS

Two-hundred-and-sixty-eight respondents (32%) provided sufficient information on their conditions to be included in the analyses. These included ischaemic heart disease (31), arrhythmias (20), cardiac septal defects (31), other cardiac conditions (10), hypertension (127), diabetes (25), asthma (40) and pneumothorax (5). Forty-nine per cent had sought specialist diving medical advice about their condition and 23% reported modifying their diving practices to mitigate their risk. The cohort had completed 183,069 career dives, 57,822 of these since being diagnosed with their medical condition. There were 27 individuals who reported having decompression illness (25 of whom were subsequently diagnosed with a persistent foramen ovale), and two individuals who experienced an arrhythmia during diving.

CONCLUSIONS

Some DAN AP members are diving with medical conditions which could potentially impact the safety of their diving. A minority modified their diving practices to mitigate the risk of their condition and approximately half sought specialist diving medical advice. The incidence of diving-related problems precipitated by known and managed pre-existing health conditions seems low but further studies of larger cohorts and incorporating fatality data would be necessary to confirm this. These results are limited by the 32% response rate and potential for bias towards selection of those most careful with their health.

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

Patent foramen ovale has been associated with multiple pulmonary diseases, such as pulmonary hypertension, platypnea-orthodeoxia syndrome, and chronic obstructive pulmonary disease. A connection between patent foramen ovale and chronic pulmonary disease was first described more than 2 decades ago in case reports associating patent foramen ovale with more severe hypoxemia than that expected based on the severity of the primary pulmonary disease. It has been suggested that patients with both chronic pulmonary disease and patent foramen ovale are subject to severe hypoxemia because of the right-to-left shunt. Furthermore, investigators have reported improved systemic oxygenation after patent foramen ovale closure in some patients with chronic pulmonary disease. This review focuses on the association between chronic pulmonary disease and patent foramen ovale and on the dynamics of a right-to-left shunt, and it considers the potential benefit of patent foramen ovale closure in patients who have hypoxemia that is excessive in relation to the degree of their pulmonary disease.

Intracardiac Right-to-Left Shunt Impeding Liberation From Veno-Venous Extracorporeal Membrane Oxygenation: Two Case Studies

OBJECTIVES

Veno-venous extracorporeal membrane oxygenation is an increasingly used form of advanced respiratory support, but its effects on the physiology of the right heart are incompletely understood. We seek to illustrate the impact of veno-venous extracorporeal membrane oxygenation return blood flow upon the right atrium by considering the physiologic effects during interatrial shunting.

PATIENTS

Two veno-venous extracorporeal membrane oxygenation patients in whom an extracorporeal membrane oxygenation induced right-to-left interatrial shunt appears to have created a barrier to liberation from extracorporeal support.

CONCLUSIONS

Veno-venous extracorporeal membrane oxygenation return flow generates a high-pressure jet that has potential to exert focal pressure upon the intra-atrial septum. In patients with potential for interatrial flow, this may lead to a right-to-left shunt, which becomes physiologically apparent only when sweep gas flow is ceased.

Shape memory polymers with enhanced visibility for magnetic resonance- and X-ray imaging modalities

Currently, monitoring of minimally invasive medical devices is performed using fluoroscopy. The risks associated with fluoroscopy, including increased risk of cancer, make this method especially unsuitable for pediatric device delivery and follow-up procedures. A more suitable method is magnetic resonance (MR) imaging, which makes use of harmless magnetic fields rather than ionizing radiation when imaging the patient; this method is safer for both the patient and the performing technicians. Unfortunately, there is a lack of research available on bulk polymeric materials to enhance MR-visibility for use in medical devices. Here we show the incorporation of both physical and chemical modifying agents for the enhancement of both MR and X-ray visibility. Through the incorporation of these additives, we are able to control shape recovery of the polymer without sacrificing the thermal transition temperatures or the mechanical properties. For long-term implantation, these MR-visible materials do not have altered degradation profiles, and the release of additives is well below significant thresholds for daily dosages of MR-visible compounds. We anticipate our materials to be a starting point for safer, MR-visible medical devices incorporating polymeric components.

STATEMENT OF SIGNIFICANCE

Shape memory polymers (SMPs) are polymeric materials with unique shape recovery abilities that are being considered for use in biomedical and medical device applications. This paper presents a methodology for the development of MR and X-ray visible SMPs using either a chemically loaded or physical loaded method during polymer synthesis. Such knowledge is imperative for the development and clinical application of SMPs for biomedical devices, specifically for minimally-invasive vascular occlusion treatments, and while there are studies pertaining to the visibility of polymeric particles, little work has been performed on the utility of biomaterials intended for medical devices and the impact of how adding multiple functionalities, such as imaging, may impact material safety and degradation.

Air Embolism: Diagnosis, Clinical Management and Outcomes

Air embolism is a rare but potentially fatal complication of surgical procedures. Rapid recognition and intervention is critical for reducing morbidity and mortality. We retrospectively characterized our experience with air embolism during medical procedures at a tertiary medical center. Electronic medical records were searched for all cases of air embolism over a 25-year period; relevant medical and imaging records were reviewed. Sixty-seven air embolism cases were identified; the mean age was 59 years (range, 3–89 years). Ninety-four percent occurred in-hospital, of which 77.8% were during an operation/invasive procedure. Vascular access-related procedures (33%) were the most commonly associated with air embolism. Clinical signs and symptoms were related to the location the air embolus; 36 cases to the right heart/pulmonary artery, 21 to the cerebrum, and 10 were attributed to patent foramen ovale (PFO). Twenty-one percent of patients underwent hyperbaric oxygen therapy (HBOT), 7.5% aspiration of the air, and 63% had no sequelae. Mortality rate was 21%; 69% died within 48 hours. Thirteen patients had immediate cardiac arrest where mortality rate was 53.8%, compared to 13.5% (p = 0.0035) in those without. Air emboli were mainly iatrogenic, primarily associated with endovascular procedures. High clinical suspicion and early treatment are critical for survival.

Valsalva maneuver in phlebologic practice

Forced expiration against an airway obstruction was originally described as a method for inflating the Eustachian tubes and is accredited to Antonio Maria Valsalva (1666-1723). The Valsalva maneuver is commonly applied for different diagnostic purposes. Its use for phlebologic diagnosis is the object this review. Venous reflux is the most frequent pathophysiologic mechanism in chronic venous disease. Reflux is easily visualized by duplex ultrasound when properly elicited, in standing position. A simple way to elicit reflux is the so-called "compression-release maneuver": by emptying the muscle reservoir, it determines a centrifugal gradient, dependent on hydrostatic pressure, creating an aspiration system from the superficial to the deep system. The same results are obtained with dynamics tests activating calf muscles. The Valsalva maneuver elicits reflux by a different mechanism, increasing the downstream pressure and, thus, highlighting any connection between the source of reflux and the refluxing vessel. The Valsalva maneuver is typically used to investigate the saphenofemoral junction. When the maneuver is performed correctly, it is very useful to analyse several conditions and different hemodynamic behaviours of the valvular system at the saphenofemoral junction. Negative Valsalva maneuver always indicates valvular competence at the saphenofemoral junction. Reverse flow lasting during the whole strain (positive Valsalva maneuver) indicates incompetence or absence of proximal valves. Coupling Valsalva maneuver to compression-release maneuver, with the sample volume in different saphenofemoral junction sections, may reveal different hemodynamic situations at the saphenofemoral junction, which can be analysed in detail.

Injection of agitated saline to detect recirculation with transthoracic echocardiography during venovenous extracorporeal oxygenation: A pilot study

PURPOSE

We assessed the security and efficiency of intravenously injected agitated saline in conjunction with transthoracic echocardiography to identify recirculation in patients supported with a venovenous extracorporeal membrane oxygenation (VV ECMO) device.

MATERIALS AND METHODS

We injected agitated saline 4 consecutive times separated by an interval of 5 minutes in 2 patients supported by VV ECMO. In both patients, the drainage cannula was placed in the left femoral vein, and the return cannula was placed in the right internal jugular vein. Echocardiography was performed during the injection and until the bubbles disappeared. The security of the method was assessed by evaluating the mechanical function of the ECMO and the efficiency of the oxygenator. The value of this method was assessed by visualizing the increase of inferior vena cava's echogenicity as well as by measuring the time required for this change to occur after the injection of agitated saline at different ECMO output levels.

RESULTS

We did not observe any change in ECMO, oxygenation function, or the hemodynamic status of patients after the 4 injections of agitated saline. The echogenicity of the inferior vena cava increased more rapidly as the ECMO's output increased. The recirculation phenomenon was noted even with low levels of ECMO output (<2 L/min).

CONCLUSIONS

Transthoracic echocardiography in conjunction with agitated saline administration may be a safe and easily applicable method to evaluate a recirculation phenomenon in patients supported with VV ECMO.

Artificial blood circulatory and special Ultrasound Doppler probes for detecting and sizing gaseous embolism

This paper presents a special designed artificial blood circulatory (ABC) for studying gaseous embolism based on detection of gaseous emboli and their sizing using ultrasound (US) spectral Doppler. Blood mimicking fluid (BMF) was used in the circulatory to get valid results without using human blood. The additional necessary degassing circulatory shows a promising effect of decontaminating the BMF from air bubbles. This offers the base for detecting and sizing microemboli using special algorithms and finally leads to reliable calculations of dangerous embolism and its air volume. Standard US probes at an integrated tissue model and a new 8-MHz central catheter ultrasound (CCUS) probe inside a superior vena cava model (SVCM) are used and deliver the Doppler spectrogram as input for automatic emboli detection and further signal analysis. First results using the newly developed 8-MHz CCUS probe inside the SVCM and its Doppler spectrogram characteristics show promising results but need more detailed studies.

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.