Pulmonary arteriovenous malformations: what the interventional radiologist needs to know

Anomalous Left Superior Vena Cava Predisposing to Recurrent Brain Abscesses: A Case Report and Review of the Literature

Brain abscess is a devastating illness, with a high risk of morbidity and mortality. Recurrent brain abscess poses a challenge to diagnosis while treatment options may differ. Right to left shunt is a lesser-explored etiology for recurrent brain abscesses. PubMed literature review was performed to study all published studies with reference to right to left cardiac shunt as a possible etiology for the recurrent brain abscesses. The authors also report a case of a young male who developed recurrent brain abscess after previous resection and treatment. Right to left cardiac shunting of deoxygenated blood is an etiology for recurrent brain abscess formation. Thorough systemic workup and multispecialty treatment is recommended to treat this relatively uncommon presentation.

Sudden pediatric death unveiling pulmonary arteriovenous malformations

Pulmonary arteriovenous malformations (PAVMs) are abnormal vascular connections between pulmonary arteries and veins, often associated with hereditary hemorrhagic telangiectasia (HHT). Most PAVMs are asymptomatic, but life-threatening complications like pulmonary hemorrhage, brain abscesses, and paradoxical emboli can emerge, so prompt diagnosis and treatment are crucial. We report a case of sudden pediatric death in a two-year-old female with no past medical history. Initial vomiting and fast deterioration resulted in a sudden cardiac arrest. The postmortem examination found histological evidence of consistent, extensive lung damage. The absence of the characteristic symptoms made for some challenges when it came to diagnosis, showing precisely that in early life, you could well have many difficulties in catching PAVMs. This case highlights the need to take PAVMs into account as a potential cause of sudden death, particularly when there are no conspicuous symptoms. Awareness among forensic pathologists and consideration of genetic analysis for HHT in such cases is crucial for accurate diagnosis and management.

Pulmonary arteriovenous malformation and a concurrent patent ductus arteriosus in a Doberman

A 7-week-old male Doberman presented with tachypnea, dyspnea and a VI/VI, left cranial, continuous heart murmur. Thoracic radiographs revealed severe left-sided cardiomegaly, presence of a rounded soft tissue opacity in the caudodorsal aspect of the thoracic cavity and signs of left-sided congestive heart failure. Clinical signs of heart failure were medically controlled. Echocardiography and computed tomography demonstrated a left-to-right shunting patent ductus arteriosus (PDA) in combination with a right-to-left shunting pulmonary arteriovenous malformation (PAVM) between the right main pulmonary artery and the right caudal pulmonary vein. Arterial blood gasses revealed mild hypoxemia. Transcatheter occlusion of the PDA using an Amplatz Canine Duct Occluder was performed. Four months post-operatively, echocardiography showed normal cardiac size and function with complete PDA closure. Thoracic radiographs revealed absence of the rounded opacity and resolution of cardiomegaly and vascular congestion. The PAVM was no longer visualized on repeated computed tomography and the arterial blood gasses were within normal limits. A PAVM connecting a pulmonary artery to a pulmonary vein has only rarely been reported in dogs. This report describes the presence of a congenital PAVM in combination with a PDA in a dog, which has not been previously reported in veterinary medicine.

Cine MRI in the Evaluation of Pulmonary Arteriovenous Malformations

We present findings on cine magnetic resonance imaging (MRI) using steady-state free precession (SSFP) pulse sequences in a patient with pulmonary arteriovenous malformation (PAVM). The technique has the advantage of demonstrating the pulsation of lesions during the cardiac cycle on cine images. It may not replace but may complement other MRI sequences in the characterization of pulmonary lesions in selected cases. To our knowledge, no prior video of cine images of PAVM has been provided in the literature.

An Update on Embolization for Pulmonary Arteriovenous Malformations

Pulmonary arteriovenous malformations are abnormal connections between a pulmonary artery and a pulmonary vein that can lead to ischemic stroke and brain abscess due to right-to-left shunting of blood. Embolization is currently considered the first treatment option for pulmonary arteriovenous malformations owing to its minimal invasiveness. This review updates the indications and techniques for the embolization of pulmonary arteriovenous malformations and determines the persistence of pulmonary arteriovenous malformations following embolization based on the most recent literature.

Heart-brain axis: Association of congenital heart abnormality and brain diseases

Brain diseases are a major burden on human health worldwide, and little is known about how most brain diseases develop. It is believed that cardiovascular diseases can affect the function of the brain, and many brain diseases are associated with heart dysfunction, which is called the heart-brain axis. Congenital heart abnormalities with anomalous hemodynamics are common treatable cardiovascular diseases. With the development of cardiovascular surgeries and interventions, the long-term survival of patients with congenital heart abnormalities continues to improve. However, physicians have reported that patients with congenital heart abnormalities have an increased risk of brain diseases in adulthood. To understand the complex association between congenital heart abnormalities and brain diseases, the paper reviews relevant clinical literature. Studies have shown that congenital heart abnormalities are associated with most brain diseases, including stroke, migraine, dementia, infection of the central nervous system, epilepsy, white matter lesions, and affective disorders. However, whether surgeries or other interventions could benefit patients with congenital heart abnormalities and brain diseases remains unclear because of limited evidence.

The role of interventional radiology in treatment of patients with hereditary hemorrhagic telangiectasia

Hereditary hemorrhagic telangiectasia (HHT) also known as Osler-Weber-Rendu disease is a rare autosomal dominant, multi-organ disorder that leads to formation of abnormal vascular connections resulting in devastating and life-threatening complications. Due to its multisystem character, wide range of clinical manifestations and variable expressivity, HHT remains a diagnostic challenge and requires close cooperation of specialists from various medical fields. Interventional radiology plays a key role in the management of this disease, helping maintain the health of HHT patients and minimize the risk of fatal complications. The aim of this article is to review clinical manifestations, diagnostic guidelines and criteria of HHT as well as to present the means of endovascular therapy in the management of HHT patients.

Update on pulmonary arteriovenous malformations

This review aimed to provide an overview of pulmonary arteriovenous malformations, including the major clinical and radiological presentations, investigation, and treatment algorithm of the condition. The primary etiology of pulmonary arteriovenous malformations is hereditary hemorrhagic telangiectasia (HHT), also known as Rendu-Osler-Weber syndrome, with mutations in the ENG gene on chromosome 9 (HHT type 1) or in the ACVRL1/ALK1 complex (HHT type 2). Epistaxis should always be evaluated when repeated, when associated with anemia, and in some cases of hypoxemia. In the investigation, contrast echocardiography and chest CT are essential for evaluating this condition. Embolization is the best treatment choice, especially for correction in cases of hypoxemia or to avoid systemic infections. Finally, disease management was addressed in special conditions such as pregnancy. CT follow-up should be performed every 3-5 years, depending on the size of the afferent and efferent vessels, and antibiotic prophylactic care should always be oriented. Ultimately, knowledge of the disease by health professionals is a crucial point for the early diagnosis of these patients in clinical practice, which can potentially modify the natural course of the disease.

Embolization in Pediatric Patients: A Comprehensive Review of Indications, Procedures, and Clinical Outcomes

Embolization in pediatric patients encompasses a large spectrum of indications, ranging from the elective treatment of congenital diseases of the cardiovascular system to the urgent management of acute hemorrhagic conditions. In particular, the endovascular treatment of central and peripheral vascular malformations and hypervascular tumors represents a wide chapter for both congenital and acquired situations. Thanks to the progressive availability of low-profile endovascular devices and new embolic materials, the mini-invasive approach has gradually overtaken surgery. In this review, the main embolization procedures will be illustrated and discussed, with a focus on clinical indications and expected outcomes. The most recent mini-invasive techniques will be described, with hints on the cutting-edge devices and embolic materials.

Application of three-dimensional computed tomography bronchography and angiography in thoracoscopic anatomical segmentectomy of the right upper lobe: A cohort study

Objective

Three-dimensional computed tomography bronchography and angiography (3D-CTBA) can provide detailed imaging information for pulmonary segmentectomy. This study aimed to investigate the safety and effectiveness of 3D-CTBA guidance of anatomical segmentectomy of the right upper lobe (RUL).

Methods

This was a retrospective analysis of anatomical segmentectomy of the RUL at the Thoracic Surgery Department of the Fourth Hospital of Hebei Medical University from December 9, 2013, to June 2, 2021. Preoperatively, all patients underwent contrast-enhanced CT of the chest (to determine the size of the pulmonary nodule) and a lung function test. 3D-CTBA has been performed since 2018; patients with vs. without 3D-CTBA were compared. Segmentectomy was performed according to nodule location.

Results

Of 139 patients (46 males and 93 females, aged 21–81 years), 93 (66.9%) completed single segmentectomy, 3 (2.2%) completed single subsegmentectomy, 29 had combined subsegmentectomy, 7 had segmentectomy combined with subsegmentectomy, and 6 had combined resection of two segments. Eighty-five (61.2%) patients underwent 3D-CTBA. 3D-CTBA cases had decreased intraoperative blood loss (67.4 ± 17.6 vs. 73.1 ± 11.0, P = 0.021) and shorter operation time (143.0 ± 10.8 vs. 133.4 ± 20.9, P = 0.001). 3D-CTBA (Beta = −7.594, 95% CI: −12.877 to −2.311, P = 0.005) and surgical procedure (Beta = 9.352, 95% CI: 3.551–15.153, P = 0.002) were independently associated with intraoperative blood loss. 3D-CTBA (Beta = −13.027, 95% CI: −18.632 to 17.422, P < 0.001) and surgical procedure (Beta = 7.072, 95% CI: 0.864–13.280, P = 0.026) were also independent factors affecting the operation time.

Conclusion

Preoperative use of 3D-CTBA to evaluate the pulmonary vessels and bronchial branch patterns of the RUL decreased blood loss and procedure time and so would be expected to improve the safety and effectiveness of thoracoscopic segmentectomy.

Imaging More than Skin-Deep: Radiologic and Dermatologic Presentations of Systemic Disorders

Background: Cutaneous manifestations of systemic diseases are diverse and sometimes precede more serious diseases and symptomatology. Similarly, radiologic imaging plays a key role in early diagnosis and determination of the extent of systemic involvement. Simultaneous awareness of skin and imaging manifestations can help the radiologist to narrow down differential diagnosis even if imaging findings are nonspecific. Aims: To improve diagnostic accuracy and patient care, it is important that clinicians and radiologists be familiar with both cutaneous and radiologic features of various systemic disorders. This article reviews cutaneous manifestations and imaging findings of commonly encountered systemic diseases. Conclusions: Familiarity with the most disease-specific skin lesions help the radiologist pinpoint a specific diagnosis and consequently, in preventing unnecessary invasive workups and contributing to improved patient care.

Hemodynamic Assessment of a Large Pulmonary Arteriovenous Malformation in a Neonate: Case Report and Review of Literature

Herein we report the case of a neonate with a prenatally diagnosed large pulmonary arteriovenous malformation, managed with minimally invasive hemodynamic monitoring in our Neonatal Intensive Care Unit. The combination of Near-Infrared Spectroscopy and Pressure Recording Analytical Method could guide neonatal management of critical cases of vascular anomalies: immediate data are offered to clinicians, from which therapeutic decisions such as timing of surgical resection are made to achieve a positive outcome. We also systemically collected and summarized information on patients' characteristics of previous cases reported in literature to data, and we compared them to our case.

Pulmonary Arteriovenous Malformations: What the Interventional Radiologist Should Know

Pulmonary arteriovenous malformations (PAVMs) are abnormal connections between the pulmonary artery and pulmonary vein bypassing the normal capillary bed causing a right-to-left shunt. The majority (80-90%) of PAVMs are associated with hereditary hemorrhagic telangiectasia (HHT). PAVMs may be asymptomatic or present with symptoms of hypoxia, shortness of breath, migraines, sequelae of paradoxical embolization, or rupture. Transcatheter embolization has become the standard of care. This article will review the clinical presentation, workup, genetics, imaging findings, embolization, complications, and follow-up for patients with PAVMs.

Management of pulmonary arteriovenous malformations involves additional factors aside from the diameter of feeding arteries: a 3-year case-case retrospective analysis

Background

Pulmonary arteriovenous malformations (PAVMs) are rare but cause various manifestations. Although the diameter of feeding arteries has been linked to treatment decisions, relationships among the characteristics of PAVMs, clinical symptoms, and treatment effect remain unclear. The present study was performed to investigate how collective characteristics of PAVMs relate to clinical symptoms and to provide proper treatment recommendations for patients with PAVMs.

Methods

We retrospectively analysed 838,447 patients’ radiographic data and medical records from January 2018 to December 2020. Patients were included if a PAVM was radiographically detected for the first time in our hospital. Ordered multivariable logistic regression and hierarchical multiple regression were performed to analyse the relationships between characteristics of PAVMs and various clinical symptoms. We investigated the management of PAVMs in four tertiary university hospitals.

Results

Detection rate of PAVMs was 0.025% (207/838,447), and 37.6% of patients (78/207) also had hereditary haemorrhagic telangiectasia. Eight patients were diagnosed with bilateral diffuse PAVMs. Two hundred thirty-six lesions were detected in 199 patients, and the mean diameter of the feeding artery was 4.13 ± 1.92 mm. Most PAVMs were the simple type and located in the peripheral pulmonary area. In total, 34.3% of patients (71/207) were symptom-free; remaining patients showed various manifestations, and respiratory symptoms were most common (dyspnoea on exertion, 47.8%). The diameter of the feeding artery and the type and the number of PAVMs were correlated with hypoxaemia (P < 0.001, P < 0.001, and P = 0.037, respectively). The collective characteristics of PAVMs were not related to the severity of central nervous system symptoms (largest diameter of feeding artery, P = 0.8; largest diameter of sac, P = 0.42; number of PAVMs, P = 0.35; type of PAVMs, P = 0.99). Various symptoms were greatly relieved after treatment. The hospital investigation showed that management of PAVMs was not generally appreciated in clinical practice.

Conclusions

Our study revealed a low detection rate of PAVMs and a low degree of association with hereditary haemorrhagic telangiectasia in the general population. Considering the connection between collective characteristics of PAVMs and various clinical symptoms, clinicians should consider the type and number of PAVMs, the largest diameter of the feeding artery, and clinical symptoms when managing patients with PAVMs.

OUP accepted manuscript

Pulmonary arteriovenous malformations (PAVMs) are a rare pulmonary arteriovenous direct traffic vascular malformation, which directly connect the pulmonary artery to the pulmonary vein without pulmonary capillary bed. Currently, surgical resection and percutaneous transcatheter embolization are the main mode of treatment. Embolization is gradually becoming the preferred treatment for people with PAVMs, because it is less invasive and easy to repeat. We describe a case of PAVMs with hemoptysis that relapsed again after three times of embolization and then only presented new symptoms of transient ischemic attack. Finally, the patient was treated by Da Vinci robotic-assisted thoracoscopic surgery, and there were no obvious post-operative complications and recurrence. It is the first report of multiple recurrent complex PAVMs and we present our experience with the treatment of recurrent PAVMs.

Dynamic contrast-enhanced (DCE) imaging: state of the art and applications in whole-body imaging

Dynamic contrast-enhanced (DCE) imaging is a non-invasive technique used for the evaluation of tissue vascularity features through imaging series acquisition after contrast medium administration. Over the years, the study technique and protocols have evolved, seeing a growing application of this method across different imaging modalities for the study of almost all body districts. The main and most consolidated current applications concern MRI imaging for the study of tumors, but an increasing number of studies are evaluating the use of this technique also for inflammatory pathologies and functional studies. Furthermore, the recent advent of artificial intelligence techniques is opening up a vast scenario for the analysis of quantitative information deriving from DCE. The purpose of this article is to provide a comprehensive update on the techniques, protocols, and clinical applications - both established and emerging - of DCE in whole-body imaging.

Angiographic features of pulmonary arteriovenous malformations: a new imaging classification system, BRAND, to guide embolisation

AIM

To introduce a new classification system for pulmonary arteriovenous malformations (PAVMs) based on the BRanches, ANgles and Diameter of the feeding artery (BRAND), which is intended provide a better understanding of the vascular structure of PAVMs and facilitate the selection of therapeutic strategies for embolisation.

MATERIALS AND METHODS

Twenty-one patients with PAVMs from 2005 to 2020 were reviewed retrospectively. According to angiographic morphology, classified the PAVMs using the BRAND classification.

RESULTS

A total of 41 PAVMs were treated with transcatheter embolisation. Based on the BRAND classification, there were four branches (9.8%), four acute angles (9.8%), and 32 occlusion sites >4 mm in diameter (78%). A total of 30 PAVMs (73.2%) were treated with occluders and plugs while the rest were embolised with coils (26.8%). Immediate technical success was achieved in all patients. In feeding arteries with acute angles, balloon-assisted tracking and trans-septal puncture techniques were used to facilitate the advancement of delivery systems. All origins of branches were preserved. Mean SaO₂ increased significantly from 79.5 ± 7.5% before embolisation to 92 ± 5.3% after embolisation (p<0.05). During a median follow-up of 5.4 years, two patients (9.5%) developed new PAVMs and required a second procedure. One patient (4.8%) underwent repeat embolisation due to the reperfusion of previously embolised PAVMs with coils.

CONCLUSIONS

BRAND classification is well suited to address the challenging feeding arteries of PAVMs and allow precise placement of the delivery system, leading to minimal procedural risk and high success rates.

Cryptogenic Stroke Caused by Pulmonary Arterial Venous Malformation with Massive Right-to-Left Shunt: A Case Report

Background

Pulmonary arterial venous malformation (PAVM) is an abnormal vascular malformation between pulmonary arteries and veins characterized by varying degrees of right-to-left shunts (RLS). Cryptogenic stroke (CS) due to paradoxical embolism (PE) caused by PAVM is relatively rare in the clinic.

Case Presentation

We report the case of a 54-year-old right-handed woman who presented with sudden-onset left-sided limb weakness for 2 h. A physical examination revealed normal vital signs but weakness in her left upper and lower limbs, graded as 1/5 using the Medical Research Council scale. Her National Institutes of Health Stroke Scale (NIHSS) score was 8, and her modified Rankin scale (mRS) was 4. Brain diffusion-weighted imaging showed acute infarction in the right basal ganglia and the radiation crown but brain magnetic resonance angiography found no obvious abnormality. A transcranial Doppler ultrasound with bubble study (TCD-b) found the rain curtain sign of microbubbles in the left middle cerebral artery, reflecting significant RLS. Transesophageal echocardiography (TEE) and transthoracic echocardiography (TTE) were conducted to distinguish between intra- and extracardiac shunts. A pulmonary computerized tomography angiogram (CTA) demonstrated a PAVM. We considered the patient had CS due to PE caused by PAVM. Thrombolytic therapy within the time window was performed. Then, transcatheter device occlusion of the arteriovenous fistula was successfully undertaken, and the patient carried on with rehabilitation training. At a 15-month follow-up, there were no catheter-related complications or recurrent stroke, and her NIHSS and mRS scores were both 0.

Conclusions

PAVM is an important risk factor for PE and CS and should not be ignored as a possible etiology in stroke patients without any other risk factors. CTA of the pulmonary artery is the recommended gold standard for diagnosing and locating a PAVM. Thrombolytic therapy within the time window combined with transcatheter device occlusion of arteriovenous malformation and rehabilitation training may benefit the recovery of patients with CS caused by PE resulting from PAVM.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40120-021-00275-y.

Assessment of patients with a suspected cardioembolic ischemic stroke. A national consensus statement

OBJECTIVES

Several cardiovascular, structural, and functional abnormalities have been considered as potential causes of cardioembolic ischemic strokes. Beyond atrial fibrillation, other sources of embolism clearly exist and may warrant urgent action, but they are only a minor part of the many stroke mechanisms and strokes that seem to be of embolic origin remain without a determined source. The associations between stroke and findings like atrial fibrillation, valve calcification, or heart failure are confounded by co-existing risk factors for atherosclerosis and vascular disease. In addition, a patent foramen ovale which is a common abnormality in the general population is mostly an innocent bystander in patients with ischemic stroke. For these reasons, experts from the national Danish societies of cardiology, neurology, stroke, and neuroradiology sought to develop a consensus document to provide national recommendations on how to manage patients with a suspected cardioembolic stroke. Design: Comprehensive literature search and analyses were done by a panel of experts and presented at a consensus meeting. Evidence supporting each subject was vetted by open discussion and statements were adjusted thereafter. Results: The most common sources of embolic stroke were identified, and the statement provides advise on how neurologist can identify cases that need referral, and what is expected by the cardiologist. Conclusions: A primary neurological and neuroradiological assessment is mandatory and neurovascular specialists should manage the initiation of secondary prophylactic treatment. If a cardioembolic stroke is suspected, a dedicated cardiologist experienced in the management of cardioembolism should provide a tailored clinical and echocardiographic assessment.

Applicability of Transthoracic Contrast Echocardiography for the Diagnosis and Treatment of Idiopathic Pulmonary Arteriovenous Malformations

Objective: To explore the preferred test to screen for pulmonary arteriovenous malformations (PAVMs) and to predict the probability of interventional embolization. Methods: We performed a retrospective observational study evaluating patients with idiopathic PAVMs from 2009 to 2019. After clinical evaluation, a total of 105 patients were studied, including 71 patients with positive digital subtraction pulmonary angiography (DSPA) findings and 34 with negative DSPA findings. The following patient data were assessed: blood test, chest radiograph, transthoracic contrast echocardiography (TTCE), and DSPA findings. Results: The majority of patients with idiopathic PAVMs were female (66.2% with positive DSPA findings). We found a good κ-coefficient of 0.77 with strong consistency for inter observer agreement concerning the pulmonary right-to-left shunt (RLS) grade on TTCE, which was superior to conventional chest radiographs. The positive predictive value (PPV) of the radiographic features for PAVMs on DSPA was 0.83 (95% CI 0.64-1.0) and 0.44 for the possibility of embolization (95% CI 0.19-0.70). The PPV of the shunt grade of PAVMs on DSPA was 0.14 (95% CI 0.01-0.29) for grade 1, 0.74 (95% CI 0.60-0.88) for grade 2, and 0.97 (95% CI 0.92-1.0) for grade 3. The PPVs of pulmonary shunt grades 2 and 3 on TTCE for the possibility of embolization for PAVMs were 0.21 (95% CI, 0.05-0.36) and 0.87 (95% CI, 0.79-0.99), respectively. Conclusion: TTCE is the preferred screening test for PAVMs. The pulmonary RLS grade on TTCE not only identifies the likelihood of PAVMs but also predicts the probability for embolization.

Pulmonary arteriovenous malformation in a child with multiple brain abscesses: A case report

Pulmonary arteriovenous malformations (PAVMs) are caused by abnormal connections between arteries and veins, which lead to right-to-left shunting of deoxygenated blood. Here, we report an 11-year-old male who presented with signs suggestive of intracranial pathology. The patient displayed signs of a chronic illness, possibly congenital malformation that was complicated by PAVM and multiple brain abscesses. This case illustrates the importance of doing a detailed examination and investigations, especially if the history alone is not helpful in making a diagnosis.

Declarations: management of a pulmonary arteriovenous fistulae by uniportal video-assisted thoracoscopic surgery: a case report

BACKGROUND

A pulmonary arteriovenous fistula (PAVF) is a rare condition that is associated with pulmonary arteriovenous malformation (PAVM). Few reports have described managing PAVMs using uniportal video-assisted thoracoscopic surgery (VATS).

CASE PRESENTATION

A 13-year-old child with PAVF in the left inferior pulmonary artery was treated by uniportal VATS with left lower lobectomy. After surgery, hemoptysis did not recur and there were no postoperative complications. Six months after the operation, postoperative review of computerized tomography showed no recrudescence of PAVF.

CONCLUSIONS

PAVF is a rare case that should be diagnosed and treated early. 3D- computerized tomography (CT) reconstruction is useful for diagnosis and preoperative assessment. The case shows that PAVF can be managed with uniportal VATS.

Case Report: Hemoptysis Caused by Pulmonary Tuberculosis Complicated With Bronchial Artery-Pulmonary Artery Fistula in Children

Bronchial artery-pulmonary artery fistula secondary to pulmonary tuberculosis is an important cause of hemoptysis in adults, but it's relatively rare in children. Bronchial artery-pulmonary artery fistulas are mostly congenital in children and may have no clinical manifestations in the early stage. Congenital bronchial artery-pulmonary fistula with pulmonary tuberculosis can lead to hemoptysis. From 2016 to 2020, two children with pulmonary tuberculosis complicated with bronchial artery and pulmonary artery fistula were admitted and treated in our hospital. We reminded pediatricians to pay attention to a variety of etiology combined with the possibility of children's hemoptysis.

[Pulmonary arteriovenous shunt - a rare cause of recurrent stroke due to paradoxical embolism]

Paradoxical embolism is one of the mechanisms of ischemic stroke in patients younger than 45 years of age, due to opening between the right and left chambers of the heart through a patent foramen ovale, an atrial or ventricular septal defect, pulmonary arteriovenous malformations (PAVMs), etc. The PAVMs are structurally abnormal vessels that provide direct capillary-free communication between the pulmonary and systemic circulations, and hence an anatomic "right-to-left" shunt. Most pulmonary malformations are congenital and associated with hereditary hemorrhagic telangiectasia (Rendu-Osler-Weber disease). This publication highlights the issues of pathogenesis, clinical presentation, diagnosis and treatment of this pathology, and also describes a clinical case in which multiple PAVMs caused repeated ischemic strokes.

Approach to Pulmonary Arteriovenous Malformations: A Comprehensive Update

Pulmonary arteriovenous malformations (PAVMs) are abnormal direct vascular communications between pulmonary arteries and veins which create high-flow right-to-left shunts. They are most frequently congenital, usually in the setting of hereditary hemorrhagic telangiectasia (HHT). PAVMs may be asymptomatic or present with a wide variety of clinical manifestations such as dyspnea, hypoxemia, or chest pain. Even when asymptomatic, presence of PAVMs increases patients' risk of serious, potentially preventable complications including stroke or brain abscess. Transcatheter embolotherapy is considered the gold standard for treatment of PAVMs. Though previous guidelines have been published regarding the management of PAVMs, several aspects of PAVM screening and management remain debated among the experts, suggesting the need for thorough reexamination of the current literature. The authors of this review present an updated approach to the diagnostic workup and management of PAVMs, with an emphasis on areas of controversy, based on the latest literature and our institutional experience.

Precision diagnosis and therapy of a case of brain abscesses associated with asymptomatic pulmonary arteriovenous fistulas

BACKGROUND

Brain abscesses, a severe infectious disease of the CNS, are usually caused by a variety of different pathogens, which include Streptococcus intermedius (S. intermedius). Pulmonary arteriovenous fistulas (PAVFs), characterized by abnormal direct communication between pulmonary artery and vein, are a rare underlying cause of brain abscesses.

CASE PRESENTATION

The patient was a previous healthy 55-year-old man who presented with 5 days of headache and fever. Cerebral magnetic resonance imaging (MRI) suggested a brain abscess. Thoracic CT scan and angiography demonstrated PAVFs. Aiding by metagenomic next-generation sequencing (mNGS) of the cerebrospinal fluid (CSF) sample which identified S. intermedius as the causative pathogen, the patient was switched to the single therapy of large dose of penicillin G and was cured precisely and economically.

CONCLUSIONS

It is an alternative way to perform mNGS to identify causative pathogens in patients with brain abscesses especially when the results of traditional bacterial culture were negative. Further thoracic CT or pulmonary angiography should also be undertaken to rule out PAVFs as the potential cause of brain abscess if the patient without any known premorbid history.