Provoked exercise desaturation in patent foramen ovale and impact of percutaneous closure

Techniques for Identifying a Patent Foramen Ovale: Transthoracic Echocardiography, Transesophageal Echocardiography, Transcranial Doppler, Right Heart Catheterization

Noninvasive and invasive imaging modalities play important roles for the detection of patent foramen ovale (PFO). Transthoracic echocardiography or transcranial Doppler bubble study can be used for initial noninvasive PFO screening. For diagnostic confirmation, transesophageal echocardiography bubble study can be utilized, a semiinvasive confirmatory test that can directly visualize a PFO. In selective cases when the diagnosis is in doubt, PFO can be accurately diagnosed invasively with right heart catheterization. Understanding the advantages and limitations of each diagnostic option will help clinicians choose the appropriate test for patients presenting with a PFO-associated condition who may benefit from percutaneous device closure.

The pathophysiology of patent foramen ovale and its related complications

The foramen ovale plays a vital role in sustaining life in-utero; however, a patent foramen ovale (PFO) after birth has been associated with pathologic sequelae in the systemic circulation including stroke/transient ischemic attack (TIA), migraine, high altitude pulmonary edema, decompression illness, platypnea-orthodeoxia syndrome (POS) and worsened severity of obstructive sleep apnea. Importantly, each of these conditions is most commonly observed among specific age groups: migraine in the 20 to 40s, stroke/TIA in the 30-50s and POS in patients >50 years of age. The common and central pathophysiologic mechanism in each of these conditions is PFO-mediated shunting of blood and its contents from the right to the left atrium. PFO-associated pathologies can therefore be divided into (1) paradoxical systemic embolization and (2) right to left shunting (RLS) of blood through the PFO. Missing in the extensive literature on these clinical syndromes are mechanistic explanations for the occurrence of RLS, including timing and the volume of blood shunted, the impact of age on RLS, and the specific anatomical pathway that blood takes from the venous system to the left atrium. Visualization of the flow pattern graphically illustrates the underlying RLS and provides a greater understanding of the critical flow dynamics that determine the frequency, volume, and pathway of flow. In the present review, we describe the important role of foramen ovale in in-utero physiology, flow visualization in patients with PFO, as well as contributing factors that work in concert with PFO to result in the diverse pathophysiological sequelae.

A Cardiologist's Perspective on Patent Foramen Ovale-Associated Conditions

The patent foramen ovale (PFO) jeopardizes health and its problems may be major. A nineteenth century case report was the first description of a PFO as cause of death. To the present day, the PFO does not get the deserved attention. A PFO is found in roughly 25% of people, its particularly dangerous forms in about 5%. Those have a high enough risk for harm by the PFO to justify screening for it for closure, even as primary prevention. After all, closing a PFO is as simple as fixing a tooth and can be considered a mechanical vaccination.

Every Patent Foramen Ovale Should Be Closed

At present, the patent foramen ovale (PFO) does not receive the deserved medical attention. The PFO poses a serious threat to health and even the life of mankind. The first respective case report in the medical literature dates back to the 19th century. It led to death. The fact that a PFO is present in roughly 25% of people underscores its overall potential to cause harm. Yet at the same time, the sheer number discourages the medical community from screening for it and from treating it. About 5% of the population have particularly dangerous forms of PFOs. Such PFOs portray a high enough risk for clinical events, the likes of death, stroke, myocardial infarction, or ocular, visceral, and peripheral embolism, to justify screening for them. Highly significant health incidents being at stake, it appears obvious that PFO closure should be used for primary prevention. This is supported by the fact that closing a PFO is the simplest intervention in cardiology, with presumably the highest clinical yield. Being mainly a preventive measure, PFO closure represents a mechanical vaccination. When closing PFOs for one of the rarer therapeutic indications (migraine, platypnea orthodeoxia, etc.), patients automatically profit from the collateral benefit of getting, at the same time, mechanically vaccinated for life against paradoxical embolism. Vice versa, closing a PFO for the prevention of paradoxical embolism betters or cures migraine or exercise dyspnea not infrequently, thereby improving quality of life as a collateral benefit.

Step by Step: Evaluation of Cardiorespiratory Fitness in Healthy Children, Young Adults, and Patients with Congenital Heart Disease Using a Simple Standardized Stair Climbing Test

(1) Background: Cardiorespiratory fitness (CRF) is known to be a prognostic factor regarding long-term morbidity and mortality. This study aimed to develop a standardized Stair Climbing Test (SCT) with a reliable correlation to spiroergometry and the 6MWT which can be used in healthy children as well as patients with congenital heart disease (CHD) and a restricted exercise capacity. (2) Methods: A total of 28 healthy participants aged 10-18 years were included. We tested the individuals' CRF by cardiopulmonary exercise testing (CPET) on a treadmill, the 6MWT, and a newly developed Stair Climbing Test (SCT). For the SCT, we defined a standardized SCT protocol with a total height of 13.14 m to achieve maximal exercise effects while recording time and vital parameters. To compare the SCT, the 6 Min Walking Test, and CPET, we introduced an SCT-Index that included patient data (weight, height) and time. To assess the SCT's feasibility for clinical practice, we also tested our protocol with five adolescents with complex congenital heart disease (i.e., Fontan circulation). (3) Results: A strong correlation was observed between SCT-Index and O2 pulse (r = 0.921; p < 0.001). In addition, when comparing the time achieved during SCT (tSCT) with VO2max (mL/min/kg) and VO2max (mL/min), strong correlations were found (r = -0.672; p < 0.001 and r = -0.764; p < 0.001). Finally, we determined a very strong correlation between SCT-Index and VO2max (mL/min) (r = 0.927; p = <0.001). When comparing the 6MWD to tSCT, there was a moderate correlation (r = -0.544; p = 0.003). It appears to be feasible in patients with Fontan circulation. (4) Conclusions: We were able to demonstrate that there is a significant correlation between our standardized SCT and treadmill CPET. Therefore, we can say that the SCT can be used as an easy supplement to CPET and in certain contexts, it can also be used as a screening tool when CPET is not available. The advantages would be that the SCT is a simple, quick, cost-effective, and reliable standardized (sub)maximal exercise test to evaluate CRF in healthy children on a routine basis. We can even assume that it can be used in patients with congenital heart disease.

The association between patent foramen ovale and unexplained syncope in pediatric patients

BACKGROUND

Patent foramen ovale (PFO) is associated with transient ischemia attack (TIA) or stroke, paradoxical embolism, and migraines. PFO closure decreases the recurrent incidence of cerebral ischemic events and reduces the incidence of syncope in adults. However, whether PFO is associated with syncope in pediatric patients has not been investigated.

METHODS

1001 pediatric patients (aged 4 to 17 years, mean age 10.31 ± 2.61 years, 519 males) who complained of unexplained syncope, palpitation, headache, dizziness and chest pain and were hospitalized in the Syncope Ward, The Second Xiangya Hospital, Central South University between January 2013 and April 2022 were recruited. Children with definite etiology of syncope, neurological, cardiogenic, psychological and other system diseases were excluded. PFO was measured by transthoracic echocardiography and right-heart contrast echocardiography was performed to identify the presence of right-to-left shunting. The demographic data and medical records were retrospectively reviewed and analyzed.

RESULTS

276 cases were included in the simple syncope group, 379 cases in the headache/dizziness group, 265 cases in the chest pain group, and 81 cases in the palpitation group. The incidence of PFO between the four groups was insignificant (4.71%, 4.74%, 4.15%, 6.17%, respectively, P = 0.903). Multivariate Logistic regression demonstrated that PFO is not associated with the increased risk of syncope (P = 0.081).

CONCLUSION

PFO may not increase the risk of syncope in pediatric patients. Further study may include a large and multicenter sample to investigate the association between PFO and unexplained syncope.

Patent Foramen Ovale Percutaneous Closure: Evolution and Ongoing Challenges

Patent foramen ovale (PFO) concerns nearly a quarter of the general population and incidence may reach up to 50% in patients with cryptogenic stroke. Recent randomized clinical trials confirmed that percutaneous closure of PFO-related stroke reduces the risk of embolic event recurrence. PFO also comes into play in other pathogenic conditions, such as migraine, decompression sickness or platypnea-orthodeoxia syndrome, where the heterogeneity of patients is high and evidence for closure is less well-documented. In this review, we describe the current indications for PFO percutaneous closure and the remaining challenges, and try to provide future directions regarding the technique and its indications.

Correlation between percutaneous patent foramen ovale closure and recurrence of unexplained syncope

Background

The relationship between patent foramen ovale (PFO) and unexplained syncope remains to be illustrated. Therefore, this study aimed to explore the outcomes and prognostic factors for syncope recurrence after PFO closure.

Methods

Patients with both large right-to-left shunting (RLS) PFO and unexplained syncope who visited the cardiovascular department of Xiangya Hospital Central South University from 1 January 2017 to 31 December 2021 were consecutively enrolled in our study. The recurrence rate of syncope was compared between the non-closure group (n = 20) and the closure group (n = 91).

Results

A total of 111 patients were finally included. After 31.11 ± 14.30 months of follow-up, only 11% of patients in the closure group had recurrent syncope, which was much lower than that of the non-closure group (11.0 vs. 35%, P = 0.018). We further investigated the possible prognostic factors for syncope recurrence in the closure group and found syncope occurring more than five times preoperatively, hypertension, and residual RLS at 12-month follow-up were significantly correlated with a higher number of recurrences.

Conclusions

PFO closure reduced the recurrence rate of unexplained syncope. The efficacy of prevention was prognosticated by factors including the presence or absence of syncope induction, the frequency of syncope episodes, and the presence or absence of hypertension. Syncope recurrence was also related to residual shunts post closure.

Effect of Interventional Therapy Unexplained Dizziness and Relationship Between Dizziness Handicap Inventory and Right-to-Left Shunt Grading

Objective

Unexplained dizziness remains a clinical challenge. Our previous studies have shown that unexplained dizziness may be related to patent foramen ovale (PFO). This study aims to explore whether the degree of shunt is correlated with the degree of unexplained dizziness and looking for the possible clinical intervention for patients with unexplained dizziness.

Methods

This study was a large single-center, prospective, controlled study. From March 2019 to March 2022, patients with unexplained dizziness and explained dizziness and healthy controls were recruited. Contrast-enhanced transcranial Doppler sonography (c-TCD) was performed to detect the existence of right-to-left shunt (RLS) and shunt grading. The dizziness handicap inventory (DHI) was completed to evaluate the dizziness. Unexplained dizziness patients with large amount of PFO were volunteered to receive medication treatment and transcatheter PFO closure and followed up six months.

Results

A total of 387 patients (132 unexplained, 123 explained and 132 controls) were enrolled. There was a statistical difference in the RLS grading with three groups (p < 0.001). The Spearman correlation coefficient of RLS grading and DHI scores in unexplained dizziness patients (r=0.122, p=0.163) and explained dizziness patients (r=0.067, p=0.460). In the unexplained group, there were 49 cases with massive grading RLS. Of which 25 patients received percutaneous PFO closure treatment and 24 cases received medication treatment. Followed up six months after treatment, the amount of DHI scores change in patients who received the percutaneous PFO closure was significantly higher than that in the medication treatment group (p < 0.001).

Conclusion

RLS may play an important role in unexplained dizziness. For unexplained dizziness patients, PFO closure may contribute to better outcomes. In the future, large-scale randomized controlled studies are still needed.

Exertional desaturations after COVID-19: A case for PFO closure

We present a case of a woman with past medical history notable for mild COVID-19 infection who presented with dyspnea on exertion, then developed progressively worsening exertional desaturations and was found to have a patent foramen ovale (PFO). Extensive cardiopulmonary testing revealed no clear alternate etiology for her symptoms. After much discussion, she underwent successful closure of the PFO with complete resolution of her symptoms and significantly improved exertional desaturation.

European position paper on the management of patients with patent foramen ovale. Part II - Decompression sickness, migraine, arterial deoxygenation syndromes and select high-risk clinical conditions

Patent foramen ovale (PFO) is implicated in the pathogenesis of a number of medical conditions but to date only one official position paper related to left circulation thromboembolism has been published. This interdisciplinary paper, prepared with the involvement of eight European scientific societies, reviews the available evidence and proposes a rationale for decision making for other PFO-related clinical conditions. In order to guarantee a strict evidence-based process, we used a modified grading of recommendations, assessment, development, and evaluation (GRADE) methodology. A critical qualitative and quantitative evaluation of diagnostic and therapeutic procedures was performed, including assessment of the risk/benefit ratio. The level of evidence and the strength of the position statements were weighed and graded according to predefined scales. Despite being based on limited and observational or low-certainty randomised data, a number of position statements were made to frame PFO management in different clinical settings, along with suggestions for new research avenues. This interdisciplinary position paper, recognising the low or very low certainty of existing evidence, provides the first approach to several PFO-related clinical scenarios beyond left circulation thromboembolism and strongly stresses the need for fresh high-quality evidence on these topics.

Percutaneous closure of a patent foramen ovale causing exercise hypoxemia: Case report and a review of the literature

Provoked exercise desaturation is a rare presentation of patent foramen ovale (PFO), when vigorous exercise leads to desaturation of arterial blood and subsequent dyspnea. We present a case of provoked exercise desaturation and curative percutaneous closure and review the literature. A 54-year-old male patient presented with shortness of breath during exercise in the pneumology outpatient department. During exercise spirometry, a relevant drop in arterial oxygen saturation and partial pressure of oxygen was observed and a right-left shunt suspected. In a transesophageal echocardiogram, a PFO was observed. Cardiac catheterization documented a right-left-shunt causing desaturation during exercise. Following percutaneous closure of the PFO, exercise induced desaturation was no longer detectable during exercise spirometry and there was considerable improvement in exercise capacity and subjective dyspnea. To sum up, provoked exercise desaturation is a rare but curable presentation of PFO. Percutaneous closure is a safe and effective way to treat this entity.

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.

[Patent foramen ovale with a license to kill]

A patent foramen ovale (PFO) is present in about one of four, and one of its dangerous forms (large or associated with atrial septal aneurysm, Eustachian valve, or Chiari network) in one of twenty people. About 140 years ago, the PFO was shown to have the potential to result in death due to stroke and also myocardial infarction. The described decrease of the prevalence of a PFO with age may be a consequence of this. Therefore, it comes somewhat as a surprise that the PFO is taken rather lightly by the medical community. Percutaneous PFO closure with implantable devices has been around for over two decades and since then has proven to be the simplest and safest technique in interventional cardiology. Nonetheless, it is rarely applied and not recommended in current guidelines except for a few situations. Countless nonrandomised comparisons have invariably pointed to a clinical benefit of PFO closure in the secondary prevention of paradoxical cerebral events in patients with or without competitive reasons for stroke. Even a survival benefit of PFO closure was shown in a comparison over 10 years. However, the first three publications of randomised trials were not significant in the protocolled sense. PFO closure did reduce recurrent events compared to medical therapy by up to 80% but the statistical significance postulated was only reached in one of the three trials when the results were analyzed as treated or per predefined subgroups, like patients with atrial septal aneurysm, large PFO, or all PFO closure patients compared to treatment with acetylsalicylic acid only. Recently, a preplanned longer-term analysis of this trial and two additional randomised trials including higher risk PFOs reached the hypothesised statistical significance. This may be a turning point in the attitude towards PFO closure. In addition, PFO closure improves migraine and dyspnoea in certain patients. It appears, though, that it will take time until the full potential of PFO closure will be reflected in respective guidelines and reimbursement algorithms and adequately exploited by referring physicians (mostly neurologists) and interventional cardiologists. This reluctance will continue to cost innumerable preventable strokes, myocardial infarctions, and deaths around the world. The low risk of PFO closure must be weighed against even death if a PFO is left open; it is much more likely that one regrets not having closed a PFO than having closed it.

Patent foramen ovale closure to prevent secondary neurologic events

In October of 2016 the United States Food and Drug Administration approved the Amplatzer Patent Foramen Ovale (PFO) occluder device for use in patients with cryptogenic stroke, to reduce the risk of recurrent stroke. This event followed 15years of off-label use of atrial septal occluder devices, 3 randomized trials, and enormous controversy over the efficacy of this procedure. While none of the trials reached the primary endpoint needed to prove the efficacy of PFO closure in preventing recurrent stroke, meta-analyses and 5-year follow-up of 1 trial suggest that PFO closure decreases the risk of recurrent stroke, especially in sub-groups with large shunts and atrial septal aneurysms, and especially when the Amplatzer device (rather than other devices) is used. While the relative reduction in stroke associated with PFO closure is large (about 50%), the absolute reduction is low (1-2%) and must be balanced against complications of the procedure (about 3%). Thus, PFO closure is restricted to patients with cryptogenic stroke, and depends heavily on patients' personal preferences. Uncertainties about the etiology of stroke in patients with PFO and the efficacy of PFO closure cause a difficult problem for the internal medicine specialist. At one extreme the internist may wonder if every patient with a documented PFO should be referred to a cardiologist. At the other extreme, supported by specialty society guidelines, internists may conclude that PFO closure is rarely necessary. In this paper we review the current status of PFO closure and suggest a rational strategy for this procedure.

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.

Physiological impact of patent foramen ovale on pulmonary gas exchange, ventilatory acclimatization, and thermoregulation

The foramen ovale, which is part of the normal fetal cardiopulmonary circulation, fails to close after birth in ∼35% of the population and represents a potential source of right-to-left shunt. Despite the prevalence of patent foramen ovale (PFO) in the general population, cardiopulmonary, exercise, thermoregulatory, and altitude physiologists may have underestimated the potential effect of this shunted blood flow on normal physiological processes in otherwise healthy humans. Because this shunted blood bypasses the respiratory system, it would not participate in either gas exchange or respiratory system cooling and may have impacts on other physiological processes that remain undetermined. The consequences of this shunted blood flow in PFO-positive (PFO+) subjects can potentially have a significant, and negative, impact on the alveolar-to-arterial oxygen difference (AaDO2), ventilatory acclimatization to high altitude and respiratory system cooling with PFO+ subjects having a wider AaDO2 at rest, during exercise after acclimatization, blunted ventilatory acclimatization, and a higher core body temperature (∼0.4(°)C) at rest and during exercise. There is also an association of PFO with high-altitude pulmonary edema and acute mountain sickness. These effects on physiological processes are likely dependent on both the presence and size of the PFO, with small PFOs not likely to have significant/measureable effects. The PFO can be an important determinant of normal physiological processes and should be considered a potential confounder to the interpretation of former and future data, particularly in small data sets where a significant number of PFO+ subjects could be present and significantly impact the measured outcomes.

Long-term follow-up after percutaneous closure of patent foramen ovale with Amplatzer PFO Occluder: a single center experience

Introduction

Patent foramen ovale (PFO) is associated with the occurrence of cryptogenic strokes, transient neurological ischemic attacks (TIA) and migraine. Therefore despite the recent ambiguous results of prospective controlled trials, percutaneous closure of PFO is still performed in many centers.

Aim

To evaluate the safety and effectiveness of percutaneous PFO closure in the prevention of recurrence of neurologic events and migraine symptoms in long-term observation.

Material and methods

In 70 patients (31 male, age: 38 ±18 years) percutaneous PFO closure was successfully performed with the Amplatzer PFO Occluder. An interview in conjunction with neurological follow-up was performed in all patients to reveal recurrence of embolism such as TIA or stroke and the presence of migraine symptoms before and after the procedure.

Results

The mean follow-up period was 857 ±363 days (median: 571 days). No serious complications of the procedure and no death were observed. Neurological events recurred in 5 (7.1%) patients – stroke in 1 patient, TIA in 3 patients, ocular embolism in 1 patient. All of these patients were over 40 years old or had other cardiovascular risk factors. Migraine was observed in 21 (30%) patients before the procedure and in 11 (15.7%) after the procedure (p = 0.04).

Conclusions

The complication rate and recurrence of neurological events in young patients after PFO closure are low. However, careful qualification and postprocedural monitoring of the patients are necessary. Patent foramen ovale closure seems to result in attenuation of migraine symptoms.

ETORPHINE-KETAMINE-MEDETOMIDINE TOTAL INTRAVENOUS ANESTHESIA IN WILD IMPALA (AEPYCEROS MELAMPUS) OF 120-MINUTE DURATION

There is a growing necessity to perform long-term anesthesia in wildlife, especially antelope. The costs and logistics of transporting wildlife to veterinary practices make surgical intervention a high-stakes operation. Thus there is a need for a field-ready total intravenous anesthesia (TIVA) infusion to maintain anesthesia in antelope. This study explored the feasibility of an etorphine-ketamine-medetomidine TIVA for field anesthesia. Ten wild-caught, adult impala ( Aepyceros melampus ) were enrolled in the study. Impala were immobilized with a standardized combination of etorphine (2 mg) and medetomidine (2.2 mg), which equated to a median (interquartile range [IQR]) etorphine and medetomidine dose of 50.1 (46.2-50.3) and 55.1 (50.8-55.4) μg/kg, respectively. Recumbency was attained in a median (IQR) time of 13.9 (12.0-16.5) min. Respiratory gas tensions, spirometry, and arterial blood gas were analyzed over a 120-min infusion. Once instrumented, the TIVA was infused as follows: etorphine at a variable rate initiated at 40 μg/kg per hour (adjusted according to intermittent deep-pain testing); ketamine and medetomidine at a fixed rate of 1.5 mg/kg per hour and 5 μg/kg per hour, respectively. The etorphine had an erratic titration to clinical effect in four impala. Arterial blood pressure and respiratory and heart rates were all within normal physiological ranges. However, arterial blood gas analysis revealed severe hypoxemia, hypercapnia, and acidosis. Oxygenation and ventilation indices were calculated and highlighted possible co-etiologies to the suspected etorphine-induced respiratory depression as the cause of the blood gas derangements. Impala recovered in the boma post atipamezole (13 mg) and naltrexone (42 mg) antagonism of medetomidine and etorphine, respectively. The etorphine-ketamine-medetomidine TIVA protocol for impala may be sufficient for field procedures of up to 120-min duration. However, hypoxemia and hypercapnia are of paramount concern and thus oxygen supplementation should be considered mandatory. Other TIVA combinations may be superior and warrant further investigation.

A 58-year-old woman with hypoxia, hypoxaemia, a hole in the heart and a … herring! Intracardiac or extracardiac shunt? That is the question!

We describe a case of a previously healthy 58-year-old woman who presented with gradual onset shortness of breath on exertion, erythrocytosis, hypoxia and hypoxaemia. Initial investigations revealed a normal chest radiography and pulmonary function test, however, there was an isolated reduction in diffusion capacity. She was subsequently found to have a patent foramen ovale (PFO) with intermittent shunting. A contrast echocardiography study hinted towards an extracardiac shunt. No shunt was detected in spite of using advanced imaging techniques. A lung biopsy was ultimately performed and histopathology revealed diffuse microvascular pulmonary arteriovenous malformations. This is one of few cases reported of this rare vascular abnormality and highlights its strong genetic association with hereditary haemorrhagic telangiectasia. The diagnostic challenges and management of this unique condition are reviewed in detail.

Imaging pitfalls, normal anatomy, and anatomical variants that can simulate disease on cardiac imaging as demonstrated on multidetector computed tomography

Advances in computed tomography have led to continuous improvement in cardiac imaging. Dedicated postprocessing capabilities, faster scan times, and cardiac gating methods reveal details of normal cardiac anatomy and anatomic variants that can mimic pathologic conditions. This article will review normal cardiac anatomy and variants that can mimic disease. Radiologists should be familiar with normal cardiac anatomy and anatomic variants to avoid misinterpretation of normal findings for pathologic processes.

Effectiveness of percutaneous closure of patent foramen ovale for hypoxemia

The aim of this study was to evaluate the ability of percutaneous patent foramen ovale (PFO) closure to improve systemic hypoxemia. Although PFO-mediated right-to-left shunt (RTLS) is associated with hypoxemia, the ability of percutaneous closure to ameliorate hypoxemia is unknown. Between 2004 and 2009, 97 patients who underwent PFO closure for systemic hypoxemia and dyspnea that was disproportionate to underlying lung disease were included for evaluation. All patients exhibited PFO-mediated RTLS as determined by agitated saline echocardiography. Procedural success was defined as implantation of a device without major complications and mild or no residual shunt at 6 months. Clinical success was defined as a composite of an improvement in New York Heart Association (NYHA) functional class, reduction of dyspnea symptoms, or decreased oxygen requirement. Procedural success was achieved in 96 of 97 (99%), and clinical success was achieved in 68 of 97 (70%). The presence of any moderate or severe interatrial shunt by agitated saline study (odds ratio [OR] = 4.7; p <0.024), NYHA class at referral (OR = 2.9; p <0.0087), and 10-year increase in age (OR = 1.8; p <0.0017) increased likelihood of clinical success. In contrast, a pulmonary comorbidity (OR = 0.18; p <0.005) and male gender (OR = 0.30; p <0.017) decreased the likelihood of success. In conclusion, based on the largest single-center experience of patients referred for PFO closure for systemic hypoxemia, PFO closure was a mechanically effective procedure with an associated improvement in echocardiographic evidence of RTLS, NYHA functional class, and oxygen requirement.

The brain's heart - therapeutic opportunities for patent foramen ovale (PFO) and neurovascular disease

Patent foramen ovale (PFO), a common congenital cardiac abnormality, is a connection between the right and left atria in the heart. As a "back door to the brain", PFO can serve as a conduit for paradoxical embolism, allowing venous thrombi to enter the arterial circulation, avoiding filtration by the lungs, and causing ischemic stroke. PFO-related strokes affect more than 150,000 people per year in the US, and PFO is present in up to 60% of migraine patients with aura, and in one out of four normal individuals. So, in such a highly prevalent condition, what are the best treatment and prevention strategies? Emerging studies show PFO-related neurovascular disease to be a multi-organ condition with varying individual risk factors that may require individualized therapeutic approaches - opening the field for new pharmacologic and therapeutic targets. The anatomy of PFO suggests that, in addition to thrombi, it can also allow harmful circulatory factors to travel directly from the venous to the arterial circulation, a concept important in finding novel therapeutic targets for PFO-related neurovascular injury. Here, we: 1) review emerging data on PFO-related injuries and clinical trials; 2) discuss potential mechanisms of PFO-related neurovascular disease in the context of multi-organ interaction and heart-brain signaling; and 3) discuss novel therapeutic targets and research frontiers. Clinical studies and molecular mapping of the circulatory landscape of this multi-organ disease will both be necessary in order to better individualize clinical treatment for a condition affecting more than a quarter of the world's population.