Pulmonary arteriovenous malformations

Multimodal ultrasound imaging for patent foramen ovale and pulmonary arteriovenous malformation in patients with cryptogenic stroke or migraine: A prospective diagnostic study

Right-to-left shunt (RLS) caused by patent foramen ovale (PFO) and pulmonary arteriovenous malformations (PAVM) have been associated with a variety of diseases, and reliable techniques for detecting RLS are essential for diagnosis. This study aimed to compare the diagnostic accuracy of multimodal ultrasound imaging, including transthoracic echocardiography (TTE) plus contrast transthoracic echocardiography (CTTE) and transesophageal echocardiography (TEE) plus contrast transesophageal echocardiography (CTEE) for PFO and PAVM in patients with cryptogenic stroke or migraine. This prospective study enrolled patients with cryptogenic stroke or migraine admitted to First Hospital of Shanxi Medical University between July 2018 and April 2023. The TTE + CTTE + TEE + CTEE multimodal ultrasound imaging was defined as the gold standard. A total of 230 patients with cryptogenic stroke (108) or migraine (122) were enrolled. The TEE + CTEE generated a better area under the receiver operator characteristic (ROC) curves (AUC) than TTE + CTTE [0.995 (0.988-1.000) vs 0.975 (0.767-0.984), P < .001], indicating better identification of PFO and PAVM. The sensitivity and specificity of the TTE + CTTE were 89.4% and 85.7%, respectively, whereas the sensitivity and specificity of TEE + CTEE were 99.1% and 100%, respectively. The missed diagnosis rate of TTE + CTTE and TEE + CTEE was 65.7 % and 12.5%, respectively. The combination of TEE + CTEE may be a more reliable and sensitive tool to detect PFO and PAVM than TTE + CTTE in patients with cryptogenic stroke or migraine.

Neurological and cardiopulmonary manifestations of pulmonary arteriovenous malformations

Pulmonary arteriovenous malformations (PAVMs) are direct pulmonary artery-to-vein connections without pulmonary capillaries that result in intrapulmonary right-to-left blood shunts. Although most patients with PAVMs may be entirely asymptomatic, PAVMs can induce a series of complications involving the neurological, cardiovascular, and respiratory systems that can lead to catastrophic and often fatal clinical sequelae. In this study we review the available literature and summarize the reported PAVM-related complications among patients with PAVMs. The reviewed studies included observational studies, case studies, prospective studies, and cohort studies, and we provide an overview of PAVM-related neurological and cardiopulmonary manifestations, including stroke, cerebral abscess, transient ischemic attack, cerebral hemorrhage, migraine, seizure, dizziness, cardiac failure, arrhythmia, myocardial infarction, cough, hypoxemia, dyspnea, respiratory failure, hemoptysis, and hemothorax. Identifying and treating PAVMs before the presentation of major complication is important because this can prevent the occurrence of complications and can result in better outcomes. PAVM patients should thus be better evaluated and managed by a multidisciplinary team because they may be in a treatable phase prior to their condition becoming life-threatening.

Large pulmonary arteriovenous malformation lost to follow-up with 10 years of asymptomatic interval growth: A case report

Pulmonary arteriovenous malformations, previously considered a rare condition, have been increasingly identified in asymptomatic patients over the past 2 decades. Usually congenital and associated with hereditary hemorrhagic telangiectasia, these fistulae result in right-to-left shunting of blood by abnormal communication of pulmonary arteries and veins lacking capillary beds. Clinical findings of right-to-left shunting in the presence of feeding and draining vessels identified on imaging confirm the diagnosis, for which the first-line therapy is embolization. This report highlights the presentation and management of a large asymptomatic PAVM detected incidentally in a patient who was lost to follow-up for 10 years and represented with acute hypoxic respiratory failure secondary to a viral infection with an interval increase of PAVM size.

Efficacy and Safety of Venous Sac Embolization With or Without Feeding Artery Embolization Versus Feeding Artery Embolization Alone in the Management of Pulmonary Arteriovenous Malformations: A Systematic Review and Meta-analysis

PURPOSE

To evaluate by meta-analysis the safety and efficacy of venous sac embolization (VSE) with or without feeding artery embolization versus feeding artery embolization (FAE) alone in the management of pulmonary arteriovenous malformations (PAVMs).

METHODS

This systematic review and meta-analysis was performed and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A systematic literature search was performed in MEDLINE, Embase, and Scopus till August 31, 2021 to identify studies comparing the safety and efficacy of VSE with or without FAE versus FAE alone in PAVMs. The success of treatment was assessed by comparing the number of PAVMs with ≥70% decrease in the size of draining vein/sac between the 2 groups. The pooled odds ratio (OR) and 95% confidence interval (95% CI) were calculated using the random-effects inverse-variance model and were used to compare pooled therapeutic efficacy between the groups.

RESULTS

Three studies were found eligible for the meta-analysis. The included studies had a total of 169 patients (119 females and 50 males). The total number of PAVMs was 298, and hereditary hemorrhagic telangiectasia was present in 119 patients. The success of treatment was higher with VSE as compared to FAE (OR=3.54, 95% CI=1.66-7.56). The minor complications were similar in both groups, and one major complication occurred in the FAE group. More coils were used in the VSE group.

CONCLUSIONS

The present systematic review and meta-analysis has consolidated the evidence that VSE with or without FAE is more efficacious than FAE alone in the management of PAVMs without any increase in the associated risk of sac rupture or coil migration.

CLINICAL IMPACT

Until high-quality data from a prospective, multicentric, randomized controlled trial becomes available, the evidence consolidated by the present systematic review and meta-analysis showing the efficacy of venous sac embolization (with or without feeding artery embolization) over feeding artery embolization alone, can be used for clinical decision-making in the management of pulmonary arterio-venous malformations.

ACR Appropriateness Criteria® Pulmonary Arteriovenous Malformation (PAVM): 2023 Update

Pulmonary arteriovenous malformations (PAVMs) occur in 30% to 50% of patients with hereditary hemorrhagic telangiectasia. Clinical presentations vary from asymptomatic disease to complications resulting from the right to left shunting of blood through the PAVM such as paradoxical stroke, brain abscesses, hypoxemia, and cardiac failure. Radiology plays an important role both in the diagnosis and treatment of PAVM. Based on different clinical scenarios, the appropriate imaging study has been reviewed and is presented in this document. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Impact of Age-Related Change in Caval Flow Ratio on Hepatic Flow Distribution in the Fontan Circulation

BACKGROUND

The Fontan operation is a palliative technique for patients born with single ventricle heart disease. The superior vena cava (SVC), inferior vena cava (IVC), and hepatic veins are connected to the pulmonary arteries in a total cavopulmonary connection by an extracardiac conduit or a lateral tunnel connection. A balanced hepatic flow distribution (HFD) to both lungs is essential to prevent pulmonary arteriovenous malformations and cyanosis. HFD is highly dependent on the local hemodynamics. The effect of age-related changes in caval inflows on HFD was evaluated using cardiac magnetic resonance data and patient-specific computational fluid dynamics modeling.

METHODS

SVC and IVC flow from 414 patients with Fontan were collected to establish a relationship between SVC:IVC flow ratio and age. Computational fluid dynamics modeling was performed in 60 (30 extracardiac and 30 lateral tunnel) patient models to quantify the HFD that corresponded to patient ages of 3, 8, and 15 years, respectively.

RESULTS

SVC:IVC flow ratio inverted at ≈8 years of age, indicating a clear shift to lower body flow predominance. Our data showed that variation of HFD in response to age-related changes in caval inflows (SVC:IVC, 2, 1, and 0.5 corresponded to ages, 3, 8, and 15+, respectively) was not significant for extracardiac but statistically significant for lateral tunnel cohorts. For all 3 caval inflow ratios, a positive correlation existed between the IVC flow distribution to both the lungs and the HFD. However, as the SVC:IVC ratio changed from 2 to 0.5 (age, 3-15+) years, the correlation's strength decreased from 0.87 to 0.64, due to potential flow perturbation as IVC flow momentum increased.

CONCLUSIONS

Our analysis provided quantitative insights into the impact of the changing caval inflows on Fontan's long-term HFD, highlighting the importance of SVC:IVC variations over time on Fontan's long-term hemodynamics. These findings broaden our understanding of Fontan hemodynamics and patient outcomes.

Life-threatening hemothorax due to rupture of pulmonary arteriovenous malformation during pregnancy

Pulmonary arteriovenous malformation (PAVM) can worsen in pregnant women due to pregnancy-related physiological changes. If a PAVM ruptures, it can become life-threatening. A 24-year-old female patient at 22 weeks of gestation presented to the hospital with chest pain and dyspnea. A simple chest radiograph revealed that the right lung was almost completely collapsed due to massive pleural effusion, and the heart was displaced to the opposite side. Closed thoracostomy was performed and 2 l of blood was drained. Chest CT revealed the presence of a PAVM in the right upper lung. Emergency surgery was performed to resect the PAVM through thoracoscopic pulmonary wedge resection. The patient experienced disseminated intravascular coagulation and acute renal insufficiency after the surgery, but eventually recovered and was discharged without any complications on the sixth postoperative day.

Case report: video-assisted thoracoscopic surgery for pulmonary arteriovenous malformation using near-infrared fluorescence with indocyanine green

BACKGROUND

Pulmonary arteriovenous malformation (PAVM) is an abnormal communication between pulmonary vasculatures and has an unclear boundary with surrounding lung tissues. At present, surgeons can only determine its location by preoperative imaging and intraoperative palpation, despite its soft texture. Indocyanine green(ICG), a near-infrared fluorophore, has been demonstrated useful in the accurate identification of vascular tissue. Therefore, we explored its application in PAVM cases.

CASE PRESENTATION

We present two PAVM cases using near-infrared fluorescence (NIF) with 25 mg ICG at 5 mg/ml to achieve intraoperative visualization of the lesion in video-assisted thoracoscopic surgery (VATS). Under the NIF mode, ICG systemic injection led to successive signaling of the anomaly and normal tissues in merely 10 s, which helped us distinguish them efficiently and precisely. A peak signal-to-background ratio of 2.2 confirmed the significant fluorescence difference and excluded interference from carbon dust.

CONCLUSIONS

We are the first to report the use of such an approach in delineating the margin of vascular malformation with high contrast, and this new finding may help minimize the damage to lung function in PAVM treatment. Further exploration and validation are needed to determine its role.

Impact of Age-related change in Caval Flow Ratio on Hepatic Flow Distribution in Fontan

Background

The Fontan operation is a palliative technique for patients born with single ventricle heart disease. The superior vena cava (SVC), inferior vena cava (IVC), and hepatic veins are connected to the pulmonary arteries in a total cavopulmonary connection by an extracardiac (EC) conduit or a lateral tunnel (LT) connection. A balanced hepatic flow distribution (HFD) to both lungs is essential to prevent pulmonary arteriovenous malformations and cyanosis. HFD is highly dependent on the local hemodynamics.

Objective

The effect of age-related changes in caval inflows on HFD was evaluated using cardiac MRI (CMR) data and patient-specific computational fluid dynamics (CFD) modeling.

Methods

SVC and IVC flow from 414 Fontan patients were collected to establish a relationship between SVC:IVC flow ratio and age. CFD modeling was performed in 60 (30 EC and 30 LT) patient models to quantify the HFD that corresponded to patient ages of 3, 8, and 15 years, respectively.

Results

SVC:IVC flow ratio inverted at ∼8 years of age, indicating a clear shift to lower body flow predominance. Our data showed that variation of HFD in response to age-related changes in caval inflows (SVC:IVC = 2,1, and 0.5 corresponded to ages 3, 8, and 15+ respectively) was not significant for EC but statistically significant for LT cohorts. For all three caval inflow ratios, a positive correlation existed between the IVC flow distribution to both the lungs and the HFD. However, as the SVC:IVC ratio changed from 2→0.5 (age 3→15+), the correlation's strength decreased from 0.87→0.64, due to potential flow perturbation as IVC flow momentum increased.

Conclusion

Our analysis provided quantitative insights into the impact of the changing caval inflows on Fontan's long-term HFD, highlighting the importance of including SVC:IVC variations over time to understand Fontan's long-term hemodynamics. These findings broaden our understanding of Fontan hemodynamics and patient outcomes.

Clinical Perspective

With improvement in standard of care and management of single ventricle patients with Fontan physiology, the population of adults with Fontan circulation is increasing. Consequently, there is a clinical need to comprehend the impact of patient growth on Fontan hemodynamics. Using CMR data, we were able to quantify the relationship between changing caval inflows and somatic growth. We then used patient-specific computational flow modeling to quantify how this relationship affected the distribution of long-term hepatic flow in extracardiac and lateral tunnel Fontan types. Our findings demonstrated the significance of including SVC:IVC changes over time in CFD modeling to learn more about the long-term hemodynamics of Fontan. Fontan surgical approaches are increasingly planned and optimized using computational flow modeling. For a patient undergoing a Fontan procedure, the workflow presented in this study that takes into account the variations in Caval inflows over time can aid in predicting the long-term hemodynamics in a planned Fontan pathway.

Vascular Malformations and Tumors: A Review of Classification and Imaging Features for Cardiothoracic Radiologists

The International Society for the Study of Vascular Anomalies (ISSVA) classification is a comprehensive histology-based scheme that was updated in 2018. It is important for cardiothoracic imagers to understand this classification to ensure that accurate terminology is used and that archaic terms are avoided when vascular lesions are described. Knowledge of the various malformations (including common conditions, such as venous malformation, arteriovenous fistula, and arteriovenous malformation) and vascular tumors allows for timely diagnosis and appropriate management. This review describes various vascular anomalies, in accordance with ISSVA classification and terminology; highlights key imaging features associated with each; and discusses the role of different imaging modalities. Keywords: Pulmonary, Soft Tissues/Skin, Vascular, Arteriovenous Malformation © RSNA, 2023.

The Shunt of It

Pulmonary arteriovenous malformations (PAVMs) are rare and most often identified in patients with hereditary hemorrhagic telangiectasia (HHT). We describe a patient with severe hypoxemia and orthodeoxia with imaging findings consistent with PAVMs. Resected lung pathologic findings confirmed the presence of numerous microscopic vascular abnormalities within the right lower lobe that was consistent with diffuse pulmonary arteriovenous shunts. Family history was negative for HHT but was positive for pulmonary arterial hypertension (PAH) in two second-degree relatives. A vascular malformation gene panel was negative for genes that commonly are associated with HHT but identified a pathogenic variant in the gene encoding bone morphogenetic protein receptor-2 (BMPR2 p.Cys123∗). Pathogenic variants in BMPR2 are a well-known cause of hereditary PAH; there have been several reports to date of patients with PAVMs and PAH. However, this is the first patient to be reported with a pathogenic variant in BMPR2 to have PAVMs in isolation.

Neglected intrapulmonary arteriovenous anastomoses: A comparative study of pulmonary right-to-left shunts in patients with patent foramen ovale

Objective

Pulmonary right-to-left shunt (P-RLS) and patent foramen ovale right-to-left shunt (PFO-RLS) often appear in combination, and there are often differences and connections between them. Intrapulmonary arteriovenous anastomoses (IPAVAs), as part of P-RLS, are often overlooked because there are no technologies to detect and identify them. This study aimed to further clarify the incidence and characteristics of P-RLS with the help of contrast transesophageal echocardiography (c-TEE) and contrast transthoracic echocardiography (c-TTE), providing a reference for clinically relevant research and patent foramen ovale (PFO) management disposal decisions.

Methods

We retrospectively investigated 414 subjects who came to our hospital for c-TEE from October 2021 to July 2022, and all subjects completed c-TTE simultaneously. 7 Patients who were newly diagnosed with an atrial septal defect were excluded. Eventually, 407 patients were included in this study. Among them, 157 patients with PFO (58 patients were treated with PFO closure subsequently) and 250 patients without PFO confirmed by c-TEE were finally enrolled. In the process, we observed and analysed the presence of P-RLS.

Results

A total of 407 patients were included in the final analysis and divided into PFO group (N = 157) and non-PFO group (N = 250) according to the results of c-TEE. Whether at rest or after Valsalva maneuver, the incidence of P-RLS was significantly higher under c-TEE than under c-TTE in the two groups (P &lt; 0.001). For both c-TTE and c-TEE, the incidence of P-RLS was slightly higher after Valsalva maneuver than at rest, but the difference was not significant (c-TTE: rest vs. Valsalva maneuver, P = 0.214; c-TEE: rest vs. Valsalva maneuver, P = 0.076). The Valsalva maneuver increased the incidence of P-RLS in the group without PFO, which was more significant in c-TEE (c-TTE: rest vs. Valsalva maneuver, P = 0.591; c-TEE: rest vs. Valsalva maneuver, P = 0.008). In both groups, the P-RLS semiquantitative grading was statistical significance under different states and examinations (P &lt; 0.001).

Conclusion

The vast majority of P-RLS are grade 1–2 and are derived from physiological IPAVAs. Even so, attention should be given to the differentiation between P-RLS and PFO-RLS. c-TEE is an effective method to detect P-RLS; however, the recruitments of c-TEE and Valsalva maneuver to P-RLS should be noted.

A GDF2 missense mutation potentially involved in the pathogenesis of hereditary hemorrhagic telangiectasia: a case report

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant vascular disease. ENG and ACVRL1 gene variants account for up to 96% of all cases, while the remaining cases are caused by SMAD4 or GDF2 variants, or by currently undiscovered mutations in coding or non-coding regions. Here, we report a 47-year-old man who presented with duodenal bulb bleeding and chronic anemia. Physical examination also revealed bleeding from the skin and gingiva. His parents were cousins and one brother and one sister died in infancy from anemia and bleeding. Head computed tomography angiography (CTA) revealed a complete fetal posterior cerebral artery located in the left side, and pulmonary CTA showed pulmonary arterial hypertension. The patient was diagnosed with HHT. Peripheral blood was collected for whole-exome sequencing. Sequencing revealed a mutation in the GDF2 gene, which encodes bone morphogenetic protein-9 (BMP-9). The detected variant, c.352A > T(p.Ile118Phe), was predicted to be a neutral polymorphism; however, the patient's plasma BMP-9 levels were greatly reduced; we predicted that this might be caused by the GDF2 variant and might be involved in the HHT pathogenesis. Further research in cell lines and animal models is needed to verify the correlation between this GDF2 variant and the pathogenesis of HHT.

Computed tomography of the airways and lungs in congenital heart disease

The presence of airway and lung disease in children with congenital heart disease is commonly observed with both cardiac CT angiography and routine chest CT. In this review we discuss abnormalities encountered on CT imaging of the chest beyond the heart and central vasculature, focusing on the airways, lung parenchyma and peripheral vasculature. Preoperative and postoperative findings are reviewed as well.

Spontaneous Hemothorax during pregnancy: A case report

Introduction and importance

Spontaneous hemothorax is a rare but life-threatening condition, which is the main cause of respiratory distress during pregnancy and after delivery without any evidence of post-traumatic injury.

Case presentation

A 34-year-old woman, pregnant at 20 weeks, presented in the emergency department complaining of dyspnea accompanied by epigastric pain, with dominance on the left side. Chest X-ray and CT-scan revealed an opacity by displacing heart to the right side. Considering, there was a probability of bleeding from venous arterial malformation. Inappropriate cervical condition two days after the patient appeared thermodynamically stable a cesarean section was performed.

Clinical discussion

Pregnancy leads to increasing the size of AVM by rising cardiac output and hypoxia. Patients who are predisposed to PAVM and intend to be pregnant should be evaluated a priori.

Conclusion

Although the hemothorax is a rare phenomenon during pregnancy, management of fetus following this critical condition requires multidisciplinary assessment.

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A 34-year-old woman, pregnant at 20 weeks, presented in the emergency department complaining of dyspnea

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A chest tube was inserted in the left hemi thorax at the Emergency department.

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Although the hemothorax is a rare phenomenon during pregnancy, management of fetus following this critical condition requires multidisciplinary assessment.

Noncontrast time-resolved pulmonary magnetic resonance angiography with consecutive beam saturation pulse and variable flip angles using three-dimensional fast spin echo: A preliminary study

To develop and validate a novel noncontrast time-resolved magnetic resonance angiography (NC TR-MRA) using consecutive beam pulses with variable flip angles for visualizing hemodynamics in the pulmonary artery, we performed phantom and volunteer studies and applied the novel NC TR-MRA to a 51-year-old woman with pulmonary arteriovenous malformation (PAVM).The novel NC TR-MRA sequence utilized consecutive multiple-beam saturation pulses with variable flip angles considering venous blood T1 relaxation to alter the visualized blood signal length. The flowing blood signal length is suppressed according to the number of beam saturation pulses. NC TR-MRA in each flow phase was assessed by subtracting the images with and without beam saturation pulses. In the flow phantom study, three flow velocities were used to simulate physiological pulmonary arterial blood flow. Signal profiles along the flow direction were evaluated in each flow phase. In the volunteer study, five healthy volunteers were recruited, and NC TR-MRA was applied to evaluate relationships between the flow-saturated time and signal enhancement rates. Four regions of interest (ROIs) were determined on the proximal and distal portions of the right basal artery. A patient with PAVM was included to validate whether a PAVM lesion could be visualized using NC TR-MRA. The visualized flow signal lengths extended proportionally with the number of beam saturation pulses in the steady-flow phantom at all velocities. In the volunteer study, NC TR-MRA images showed signal enhancement from the proximal to distal portions of the right basal artery with increase in the flow-saturated time. Signal enhancement rates in all ROIs were significantly positively correlated with the flow-saturated time (p < 0.001 in all ROIs). Further, the lesion and its hemodynamics could be explicitly visualized in the patient with PAVM. Hence, NC TR-MRA using beam saturation pulse can visualize the hemodynamics of the pulmonary artery and may be useful for diagnosing and following patients with PAVM.

Significance of transesophageal contrast echocardiography with the agitated saline test for diagnosing pulmonary arteriovenous malformations

Objectives

This study evaluated the diagnostic value of transesophageal contrast echocardiography (TECE) with the agitated saline test for diagnosing pulmonary arteriovenous malformations (PAVMs) in comparison with chest CT or pulmonary angiography.

Background

Although transthoracic contrast echocardiography (TTCE) is the recommended screening test for diagnosing PAVMs, it has low specificity and positive predictive value. TECE is expected to offer improved sensitivity and specificity compared with TTCE, but no studies have reported the diagnostic accuracy and clinical significance of TECE in detecting PAVMs.

Methods and results

In total, 1,809 patients underwent TECE with the agitated saline test to evaluate symptoms of a suspected right to left shunt. Patients with hereditary hemorrhagic telangiectasia (HHT) were excluded. A total of 387 patients showed transpulmonary bubble passage, indicating a PAVM. Among them, 182 patients had additional chest CT or pulmonary angiography. Those patients were divided into two groups according to the presence of a PAVM in the radiologic imaging. A total of 18 patients (9.8%) were confirmed for the PAVM group. Only 13 patients required embolization for their PAVMs. The TECE with saline test results were divided into four grades according to the number of bubbles: grade 1 (n = 91), grade 2 (n = 47), grade 3 (n = 35), and grade 4 (n = 9). None of the patients in the PAVM group had grade 1 shunts in their TECE results. The positive predictive values for the presence of a PAVM according to the TECE grade scale were 10.6% for grade 2, 22.8% for grade 3, and 55.6% for grade 4.

Conclusion

TECE with a grade scale is a useful method for initially diagnosing PAVMs in non-HHT patients with a suspected right to left shunt. The findings of this study also suggest that patients with a small grade (<10 bubbles) shunt in their TECE findings should be spared unnecessary radiation exposure from CT scans or pulmonary angiography.

Uncommon Female-Predominant Etiologies of Cryptogenic Stroke

The etiologies of cryptogenic stroke are complex and heterogeneous. A number of uncommon etiologies are not fully recognized, some of which predominantly affect females. Most of these etiologies are closely related to the hormonal level, reproductive factors, coagulation function, and medications of females. Moreover, once cryptogenic stroke is diagnosed, females tend to have worse outcomes. Therefore, prompt etiological recognition and treatment are crucial for good recovery. The aim of this article is to review advances in exploring uncommon female-predominant etiologies of cryptogenic stroke. These etiologies are categorized into arterial, cardiac, and venous sources. Arterial vasoconstrictive narrowing, intimal injury, and intimal developmental abnormality can cause brain ischemia or artery-to-artery cerebral embolism. Myocardial contraction dysfunction, cardiac wall injury, and developmental abnormality can induce intracardiac thrombosis and lead to cardiac embolism. In addition, cortical venous thrombosis and occult venous thromboembolism via intracardiac or extracardiac channels also account for cryptogenic stroke in females. Due to the lack of knowledge, in clinical practice, the above etiologies are seldom assessed. The low incidence rate of these etiologies can lead to missed diagnosis. This review will provide novel clinical clues for the etiological diagnosis of cryptogenic stroke and will help to improve the management and secondary prevention of stroke in the female population. In the future, more studies are needed to explore the etiology and prevention strategies of cryptogenic stroke.

Traffic Patterns of the Migrating Endothelium: How Force Transmission Regulates Vascular Malformation and Functional Shunting During Angiogenic Remodelling

Angiogenesis occurs in distinct phases: initial spouting is followed by remodelling in which endothelial cells (ECs) composing blood vessels rearrange by migrating against the direction of flow. Abnormal remodelling can result in vascular malformation. Such is the case in mutation of the Alk1 receptor within the mouse retina which disrupts flow-migration coupling, creating mixed populations of ECs polarised with/against flow which aggregate into arteriovenous malformations (AVMs). The lack of live imaging options in vivo means that the collective EC dynamics that drive AVM and the consequences of mixed populations of polarity remain a mystery. Therefore, our goal is to present a novel agent-based model to provide theoretical insight into EC force transmission and collective dynamics during angiogenic remodelling. Force transmission between neighbouring agents consists of extrusive forces which maintain spacing and cohesive forces which maintain the collective. We performed migration simulations within uniformly polarised populations (against flow) and mixed polarity (with/against flow). Within uniformly polarised populations, extrusive forces stabilised the plexus by facilitating EC intercalation which ensures that cells remained evenly distributed. Excess cohesion disrupts intercalation, resulting in aggregations of cells and functional shunting. Excess cohesion between ECs prevents them from resolving diameter balances within the plexus, leading to prolonged flow reversals which exert a critical behaviour change within the system as they switch the direction of cell migration and traffic patterns at bifurcations. Introducing mixtures of cell polarity dramatically changed the role of extrusive forces within the system. At low extrusion, opposing ECs were able to move past each other; however, at high extrusion the pushing between cells resulted in migration speeds close to zero, forming traffic jams and disrupting migration. In our study, we produced vascular malformations and functional shunting with either excess cohesion between ECs or mixtures of cell polarity. At the centre of both these mechanisms are cell-cell adherens junctions, which are involved in flow sensing/polarity and must remodelling dynamically to allow rearrangements of cells during vascular patterning. Thus, our findings implicate junctional dysfunction as a new target in the treatment and prevention of vascular disease and AVMs.

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.

Ischemic stroke due to sporadic and genetic pulmonary arteriovenous malformations: Case report

Pulmonary arteriovenous malformations (PAVMs) encompass congenital and genetic vascular anomalies characterized by complex interlacing of arteries and veins connected by fistulas, which allow rapid and continuous extracardiac right-to-left shunting (RLS). Presenting neurologic manifestations of PAVM include brain abscess and stroke, as the consequence of paradoxical embolism. Although rare, PAVM represents an overlooked cause of cryptogenic ischemic stroke in young adults, being misdiagnosed as patent foramen ovale and a preventable trigger of silent cerebral ischemic changes. In the emergency clinical setting, the recommended ischemic stroke workup in patients with RLS should include the influence of postural changes and the effect of Valsalva maneuver on the entity of the RLS on contrast-enhanced transcranial color Doppler ultrasound and the delay in the right inferior pulmonary vein and left heart opacification on contrast-enhanced transthoracic echocardiography. This is in addition to the evaluation of chest X-rays or thoracic computed tomography. We here describe two patients with ischemic stroke due to sporadic and genetic PAVM-associated paradoxical embolism.

Imaging to intervention: a review of what the Interventionalist needs to Know about Hereditary Hemorrhagic Telangiectasia

Hereditary hemorrhagic telangiectasia (HHT) is a disorder that affects 1 in 5000-10,000 people worldwide and can result in devastating complications such as cerebral abscess, stroke, massive hemorrhage, and even death. HHT is an autosomal dominant disorder that leads to the formation of abnormal communication between the arteries and veins with a resultant spectrum of vascular anomalies. The disorder affects many organ systems and thus requires a dedicated multidisciplinary approach. Interventional radiologists are vital members of this team providing expertise not only in disease management, but in complex embolotherapy, helping to maintain the health of these patients. This article reviews clinical manifestations, screening guidelines, diagnostic criteria, and endovascular management of HHT.

[A case of pulmonary arteriovenous malformation treated surgically]

Pulmonary arteriovenous malformation is a rare abnormality consisting of a direct connection between the arteries and the pulmonary veins. Most of the malformations are related to hereditary hemorrhagic telangiectasia, although 10 to 20% cases are idiopathic. Clinical manifestations are due to right-to-left shunting. Embolization is the treatment of choice, when it is possible and accessible. Surgery continues to be appropriate in certain cases. We report the case of a woman who presented with an isolated complex arteriovenous malformation fed by two afferent arteries, a lingular one and an antero-basal one. Surgical treatment by lingual and antero-basal bisegmentectomy was undertaken with a good outcome.

Predictors of heart failure symptoms in hereditary hemorrhagic telangiectasia patients with hepatic arteriovenous malformations

BACKGROUND

Hepatic arteriovenous malformations (AVMs) in hereditary hemorrhagic telangiectasia (HHT) patients are most commonly hepatic artery to hepatic venous shunts which can result in high-output heart failure. This condition can be debilitating and is a leading cause of liver transplantation in HHT patients. However, it is not known what characteristics can discriminate between asymptomatic patients and those who will develop heart failure symptoms.

RESULTS

176 patients with HHT were evaluated with computed tomography angiography (CTA) between April 2004 and February 2019 at our HHT Center of Excellence. 63/176 (35.8%) patients were found to have hepatic AVMs on CTA. 18 of these patients were excluded because of the presence of another condition which could confound evaluation of heart failure symptoms. In the remaining 45 patients included in our cohort, 25/45 (55.6%) patients were classified as asymptomatic and 20/45 (44.4%) were classified as symptomatic, and these groups were compared. In symptomatic patients, mean common hepatic artery (CHA) diameter was significantly higher (11.1 versus 8.4 mm) and mean hemoglobin levels were significantly lower (10.7 vs 12.6 g/dL). A stepwise multiple logistic regression analysis demonstrated that both CHA diameter and hemoglobin level were independent predictors of heart failure symptoms with ORs of 2.554 (95% CI 1.372-4.754) and 0.489 (95% CI 0.299-0.799), respectively. The receiver operator characteristic (ROC) curve of our analysis demonstrated an AUC of 0.906 (95% CI 0.816-0.996), sensitivity 80.0% (95% CI 55.7-93.4%), and specificity 75.0% (95% CI 52.9-89.4%).

CONCLUSIONS

CTA is an effective and easily reproducible method to evaluate hepatic involvement of HHT. Utilizing CTA, clinical, and laboratory data we determined CHA diameter and hemoglobin level were independent predictors of heart failure symptoms.

Pulmonary arteriovenous malformation as a cause of ischaemic stroke in the elderly

Pulmonary arteriovenous malformation (PAVM) is well recognised as a cause of paradoxical brain embolism. The authors report the case of an older woman with a medical history of arterial hypertension who was found unconscious and was discovered to have pulmonary thromboembolism and ischaemic stroke related to a PAVM.

A novel endoglin mutation in a family with hereditary hemorrhagic telangiectasia: a case report

Hereditary hemorrhagic telangiectasis (HHT) is an autosomal dominant vascular disease, and approximately 80% of all HHT cases are caused by gene mutation. In this report, we analyzed the case of an 11-year-old girl who had intracranial bleeding when she was 7 years old. Her brain computed tomography (CT) scans and craniocerebral angiography results revealed that she had multiple cerebral arteriovenous malformations (CAVMs). Cardiac computed tomography angiography (CTA) revealed a pulmonary arteriovenous malformation (PAVM) located in a segment of the left lung. This patient's primary diagnosis was of CAVMs and PAVMs. Both cerebral vascular embolization therapy and interventional treatment for PAVMs were performed to treat these respective conditions. The operations were successful and the patient's prognosis was good. To confirm the patient's diagnosis and the cause of her conditions, peripheral blood was collected from her and her family for whole-exome sequencing (WES). Sanger sequencing was used to verify these results and STRUM software was used to predict the presence of mutant proteins. We found a new mutation of the endoglin (ENG) gene present in this family; this mutation is known as c.1466del (p.Gln489Argfs*2). The patient's mother was a carrier of this heterozygous mutation. STRUM software confirmed that the configuration of the ENG protein p.Gln489Argfs2 site changed with this mutation. We believe this c.1466del (p.Gln489Argfs*2) mutation affects ENG protein function, and the resultant ENG protein dysfunction leads to HHT. When a child has multiple vascular malformation, HHT should be considered as a primary diagnosis.

Multiple strokes due to pulmonary arteriovenous malformation

We present a case of recurrent strokes in a patient with absent left internal carotid artery (ICA) and pulmonary arteriovenous malformation. Pulmonary arteriovenous malformations (PAVMs) are abnormal communications between pulmonary artery and pulmonary vein, cause extracardiac right to left shunting of blood and are known to significantly increase the risk of stroke primarily due to paradoxical embolization. They are often hereditary and are commonly associated with hereditary hemorrhagic telangiectasias (HHT). Delayed bubbles seen in the left ventricle (after 3 cardiac cycles) on transthoracic echocardiogram with bubble study is often the first clue to the presence of PAVMs. CT scan of the chest can confirm the diagnosis. Percutaneous embolotherapy is the treatment of choice with reduction in stroke risk post embolization.

Massive haemorrhagic complications of ruptured pulmonary arteriovenous malformations: outcomes from a 12 years' retrospective study

Background

The life-threatening haemorrhagic complications of pulmonary arteriovenous malformations (PAVMs) are extremely rare, and only described in isolated cases. This study was designed to comprehensively investigate management of ruptured PAVMs.

Methods

We retrospectively assessed clinical and imaging data of ruptured PAVMs to summarize incidence, clinical characteristics, and outcomes following embolisation between January 2008 and January 2021.

Results

Eighteen of 406 (4.4%) patients with PAVMs developed haemorrhagic complications. Twelve of 18 patients were clinically diagnosed with hereditary haemorrhagic telangiectasia (HHT). Haemorrhagic complications occurred with no clear trigger in all cases. Eight of 18 patients (44.4%) were initially misdiagnosed or had undergone early ineffective treatment. 28 lesions were detected, with 89.3% of them located in peripheral lung. Computed tomography angiography (CTA) showed indirect signs to indicate ruptured PAVMs in all cases. Lower haemoglobin concentrations were associated with the diameter of afferent arteries in the ruptured lesions. Successful embolotherapy was achieved in all cases. After embolotherapy, arterial oxygen saturation improved and bleeding was controlled (P < 0.05). The mean follow-up time was 3.2 ± 2.5 years (range, 7 months to 10 years).

Conclusions

Life threatening haemorrhagic complications of PAVMs are rare, they usually occur without a trigger and can be easily misdiagnosed. HHT and larger size of afferent arteries are major risk factors of these complications. CTA is a useful tool for diagnosis and therapeutic guidance for ruptured PAVMs. Embolotherapy is an effective therapy for this life-threatening complication.

Young stroke due to pulmonary arteriovenous malformation

Young patients presenting with cryptogenic stroke should be investigated for cardiac and extra-cardiac sources of emboli. We present a patient who was investigated for a cardiac source of emboli, following multiple ischaemic strokes and migraine with aura over a period of 17 years. The events were initially thought to be related to a patent foramen ovale (PFO) on bubble contrast echocardiography, however, due to an unusual flow pattern to the left heart, she underwent a CT angiogram to exclude intrapulmonary shunting. This confirmed the presence of a moderate sized congenital pulmonary arteriovenous fistula in the left lung. Transcatheter occlusion of the vascular malformation has resolution of her symptoms. Bubble contrast echocardiography is routinely used to diagnose a PFO in these cases, but extreme caution is required during the procedure to differentiate the pattern of flow seen in patients with a pulmonary arteriovenous malformation.

Learning Tubule-Sensitive CNNs for Pulmonary Airway and Artery-Vein Segmentation in CT

Training convolutional neural networks (CNNs) for segmentation of pulmonary airway, artery, and vein is challenging due to sparse supervisory signals caused by the severe class imbalance between tubular targets and background. We present a CNNs-based method for accurate airway and artery-vein segmentation in non-contrast computed tomography. It enjoys superior sensitivity to tenuous peripheral bronchioles, arterioles, and venules. The method first uses a feature recalibration module to make the best use of features learned from the neural networks. Spatial information of features is properly integrated to retain relative priority of activated regions, which benefits the subsequent channel-wise recalibration. Then, attention distillation module is introduced to reinforce representation learning of tubular objects. Fine-grained details in high-resolution attention maps are passing down from one layer to its previous layer recursively to enrich context. Anatomy prior of lung context map and distance transform map is designed and incorporated for better artery-vein differentiation capacity. Extensive experiments demonstrated considerable performance gains brought by these components. Compared with state-of-the-art methods, our method extracted much more branches while maintaining competitive overall segmentation performance. Codes and models are available at http://www.pami.sjtu.edu.cn/News/56.

Screening in cryptogenic brain abscess: Do not forget pulmonary arteriovenous malformations

Background:

Brain abscess usually occurs secondary to trauma, through contiguous spread (e.g.; dental infections, [paranasal] sinusitis, otitis, and mastoiditis), after intracranial neurosurgical procedures, or through hematogenous spread in case of an arteriovenous (AV) shunt, for example; atrial septum defect. Although uncommon, another possible cause of AV shunt which can facilitate brain abscess is a pulmonary arteriovenous malformation (PAVM). We report a case of brain abscess secondary to a solitary PAVM and review the literature.

Case Description:

A 74-year-old male patient presented with headaches, fatigue, low-grade fever, and homonymous hemianopsia. He was diagnosed with a brain abscess in the left occipital lobe. A chest computed tomography (CT) with intravenous (IV) contrast was performed because of fever and respiratory insufficiency in a period where screening for COVID-19 in suspected patients was important. A solitary PAVM of the left lung was diagnosed. Initial stereotactic burr hole drainage of the abscess was insufficient and resection of the abscess was deemed necessary. Routine workup did not reveal any additional pathology apart from the PAVM. After treatment of the cerebral abscess, the PAVM was treated with embolization using an endovascular plug.

Conclusion:

It is recommended to screen for PAVM by chest CT with IV contrast in patients with brain abscess when no obvious source of infection can be identified.

Pulmonary Vascular Complications in Hereditary Hemorrhagic Telangiectasia and the Underlying Pathophysiology

In this review, we discuss the role of transforming growth factor-beta (TGF-β) in the development of pulmonary vascular disease (PVD), both pulmonary arteriovenous malformations (AVM) and pulmonary hypertension (PH), in hereditary hemorrhagic telangiectasia (HHT). HHT or Rendu-Osler-Weber disease is an autosomal dominant genetic disorder with an estimated prevalence of 1 in 5000 persons and characterized by epistaxis, telangiectasia and AVMs in more than 80% of cases, HHT is caused by a mutation in the ENG gene on chromosome 9 encoding for the protein endoglin or activin receptor-like kinase 1 (ACVRL1) gene on chromosome 12 encoding for the protein ALK-1, resulting in HHT type 1 or HHT type 2, respectively. A third disease-causing mutation has been found in the SMAD-4 gene, causing a combination of HHT and juvenile polyposis coli. All three genes play a role in the TGF-β signaling pathway that is essential in angiogenesis where it plays a pivotal role in neoangiogenesis, vessel maturation and stabilization. PH is characterized by elevated mean pulmonary arterial pressure caused by a variety of different underlying pathologies. HHT carries an additional increased risk of PH because of high cardiac output as a result of anemia and shunting through hepatic AVMs, or development of pulmonary arterial hypertension due to interference of the TGF-β pathway. HHT in combination with PH is associated with a worse prognosis due to right-sided cardiac failure. The treatment of PVD in HHT includes medical or interventional therapy.

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.

Evaluation of percutaneous transcatheter embolization for pulmonary arteriovenous malformations

BACKGROUND

The purpose of this study was to assess the safety and efficacy of percutaneous transcatheter embolization (TCE) for the treatment of pulmonary arteriovenous malformations (PAVMs).

METHODS

Forty-three consecutive patients (n = 17 males; n = 26 females) with 72 untreated PAVMs underwent coil and/or plug embolization between January 2010 and February 2018. The mean patient age was 42 ± 14 years (range 19-71 years). The median size of the feeding artery was 7.9 ± 2.9 mm (range 3.5-14.0 mm). The arterial blood gas level and cardiac function of all patients were analysed. The technical success rate, recanalization rate, and complications were evaluated. Computed tomography angiography (CTA) examinations were scheduled for 12 months after treatment and every 2-4 years thereafter.

RESULTS

Twenty-five PAVMs were treated with coils alone, twenty-one were treated with plugs alone, and twenty-six were treated with both coils and plugs. The technical success rate was 100%. There were no complications during operation. However, one patient (2.3%) had pulmonary thrombosis and embolism post-operation. The patients' pre-operative and post-operative PaO₂ and SaO₂ levels were significantly different (p < 0.01). A comparison of the New York Heart Association (NYHA) grade before and after embolization in all patients showed a significant decrease in the post-operative grade (p < 0.01). The 72 PAVMs were divided into three groups (coils only group [n = 25], plugs only group [n = 21], and coils/plugs combined group [n = 26]). After 12 months of follow-up, there were seven reperfusion PAVMs in the coil group, seven reperfusion PAVMs in the plug group, and 1 reperfusion PAVM in the combined group. There were significant differences between the two groups and the combined group.

CONCLUSION

Percutaneous TCE is safe and effective for the treatment of PAVMs. A combination of coils and vascular plugs may be useful for preventing recanalization after the embolization of PAVMs.

[Sudden convulsion with multiple pulmonary nodules in a girl aged 15 years]

A girl, aged 15 years, was admitted due to sudden convulsion once and multiple pulmonary nodules on lung CT. Acrocyanosis or acropachy/toe deformity was not observed. Laboratory examinations showed an increase in hemoglobin (162 g/L) and a reduction in arterial partial pressure of oxygen (61.5 mm Hg). Lung CT showed irregular slightly high-density nodules in the middle lobe of the right lung, and contrast-enhanced CT scan showed obvious enhancement with thick vascular shadow locally. An investigation of medical history revealed that the girl's mother had a history of epistaxis and resection of pulmonary mass and the girl presented with tongue telangiectasia. The girl was diagnosed with hereditary hemorrhagic telangiectasia and pulmonary arteriovenous malformation. she was given interventional embolization therapy. Transcutaneous oxygen saturation reached 98% without oxygen inhalation on the day after surgery. Pulmonary angiography at 3 months after surgery showed the recurrence of pulmonary vascular malformation, and embolization of pulmonary arterial fistula was not performed since the guide wire could not enter the branch artery. There was still a need for long-term follow-up.

Resection of clustered arteriovenous malformations to avoid lung transplantation

A 54-year-old man with hereditary hemorrhagic telangiectasia and severe hypoxemia was referred for lung transplantation. Embolization had not been performed because of numerous bilateral small pulmonary arteriovenous malformations. Although he appeared to be qualified for lung transplantation, we instead performed bilateral thoracoscopic multiple wide wedge resections because of his age, lifestyle as a farmer, and relatively clustered distribution of arteriovenous malformations. Intermittent bilateral ventilation was needed because of poor oxygenation in the early stages of surgery, but his oxygenation improved as the resection progressed. His postoperative oxygenation improved significantly, and lung transplantation was avoided.

Clinical Analysis of Transcatheter Embolotherapy for Congenital Pulmonary Arteriovenous Fistulas in Children

Objective: To summarize the clinical features and therapeutic effects of transcatheter embolotherapy for congenital pulmonary arteriovenous fistulas (PAVFs) in children, and to explore the method and therapeutic principle of transcatheter embolotherapy for congenital PAVFs in children.Method: We retrospectively reviewed nine patients with PAVF who underwent transcatheter embolotherapy in the Children’s Hospital of Chongqing Medical University from July 2004 to July 2019, including the demographic characteristics, clinical manifestations, efficiency of closure, and follow-up.Results: Transcatheter embolotherapy was successful in all cases, and the symptom remission rate was 100% during the follow-up. No residual shunts or other complications occurred during the follow-up period. Compared with before embolotherapy, there were significant changes in the percentage of saturated oxyhemoglobin and total hemoglobin level at the last follow-up (t=10.06, P=0.000; t=3.055, P=0.0076). No significant difference was observed in pulmonary artery pressure before and after embolotherapy (t=0.13, P=0.90).Conclusions: Transcatheter embolotherapy offers the advantages of safety, with a decreased risk of trauma and a specific effect of treatment, and therefore is recommended as the first-line treatment for congenital PAVFs in children. However, continued research is necessary to understand the full potential of transcatheter embolotherapy.

Pulmonary Arteriovenous Malformations in Non-hereditary Hemorrhagic Telangiectasia Patients: An 18-Year Retrospective Study

PURPOSE

Pulmonary arteriovenous malformations (PAVMs) are most commonly associated with hereditary hemorrhagic telangiectasia (HHT). Patients with PAVMs can present with serious complications including stroke, transient ischemic attack (TIA), and brain abscess. PAVMs are rare in non-HHT patients and little is known about this patient population. The aim of this retrospective study is to better understand clinical presentation and outcomes of PAVMs occurring exclusively in non-HHT patients.

METHODS

Non-HHT patients with PAVMs at the Mayo Clinic-Rochester between 01/01/2000 and 12/31/2018 were reviewed. Patients with Curacao score > 1 were excluded. Demographics, imaging characteristics, neurological complications, and follow-up imaging were analyzed.

RESULTS

Seventy-seven patients with PAVMs were identified. The mean age at diagnosis was 48.2 ± 18.3 years with female preponderance (59.7%). The majority of PAVMs had lower lobe predominance (66.7%) and were simple and single in 75.3% and 89.6% of cases, respectively. Most patients were asymptomatic (46.8%) with dyspnea being the most common symptom (28.6%). Neurologic complications occurred in 19.5% of patients. The majority of PAVMs were idiopathic (61%). Thirty patients (39%) had one or more possible risk factors including previous thoracic surgery (23.4%), congenital heart disease (19.5%), and chest trauma (10.4%). Embolization was performed in 37 (48.1%) patients and only 4 (5.2%) underwent surgical resection.

CONCLUSIONS

Non-HHT PAVMs occur more commonly in females, are most commonly simple and single, and have lower lobe predominance and a high rate of neurologic complications. Potential predisposing risk factors were identified in about 40% of the cases. Clinicians should be aware of the risk of PAVM development in patients with history of chest trauma, congenital heart disease, lung infection/abscess, and thoracic surgery.

Pulmonary arteriovenous fistula ruptured in an adolescent girl 1 week after her mother's rupture: a report of a case

A 14-year-old girl was diagnosed with hemothorax associated with pulmonary arteriovenous fistula rupture, and emergency surgery was performed. One week before her surgery, her mother at 32 weeks of gestation underwent emergency surgery for hemothorax caused by pulmonary arteriovenous fistula rupture. Both were diagnosed with hereditary hemorrhagic telangiectasia. The indications for treatment of pulmonary arteriovenous fistulas in young patients remain controversial because the risk of complications concerning pulmonary arteriovenous fistula is lower in young patients than in adult patients. We recommend that aggressive treatment should be performed for pulmonary arteriovenous fistulas in patients with hereditary hemorrhagic telangiectasis with a family history of pulmonary arteriovenous fistula rupture even if the patient is asymptomatic and young, because such patients may have a high risk of pulmonary arteriovenous fistula rupture.

Postembolotherapy Pulmonary Arteriovenous Malformation Follow-Up: A Role for Graded Transthoracic Contrast Echocardiography Prior to High-Resolution Chest CT Scan

BACKGROUND

High-resolution chest CT (HRCT) scan is recommended after pulmonary arteriovenous malformation (PAVM) embolotherapy to assess for PAVM persistence and untreated PAVM growth. Graded transthoracic contrast echocardiography (TTCE) predicts the need for embolotherapy in PAVM screening. This study sought to determine whether postembolotherapy graded TTCE can similarly predict the need for repeat embolotherapy.

METHODS

Thirty-two patients (8 men and 24 women; mean age, 51.1 ± 12.6 years) with prior PAVM embolotherapy and follow-up HRCT scan were prospectively enrolled. Patients underwent graded TTCE using a validated three-point quantitative grading scale. TTCE grade and HRCT findings were compared.

RESULTS

Median time between most recent HRCT scan and TTCE was 7 days (interquartile range, 0-272 days). Thirty patients (94%) had no PAVMs requiring repeat embolotherapy on HRCT scan. Two patients (6%) had PAVMs requiring repeat embolotherapy (feeding artery [FA] ≥ 3 mm), one with untreated PAVM growth and one with treated PAVM persistence. TTCE was positive in 88% of patients (n = 28). All patients (n = 4, 12%) with negative TTCE had no visible PAVMs on HRCT scan. Nine patients (32%) had grade 1 shunt, 10 (35%) had grade 2 shunt, and nine (32%) had grade 3 shunt. No patients with grade 1 shunt had PAVMs amenable to repeat embolotherapy on HRCT scan. All patients (n = 2) with PAVMs requiring repeat embolotherapy (FA ≥ 3 mm) had grade 3 shunt. TTCE grade was significantly associated with PAVM FA diameter (P < .001).

CONCLUSIONS

Postembolotherapy graded TTCE can predict the need for repeat embolotherapy on HRCT scan. Patients with negative TTCE and grade 1 shunt may not require HRCT follow-up and can potentially be followed with serial graded TTCE.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT02936349; URL: www.clinicaltrials.gov.

Embolisation of pulmonary arteriovenous malformations using high-frequency jet ventilation: benefits of minimising respiratory motion

Background

To evaluate patient radiation dose and procedural duration recorded during pulmonary arteriovenous malformation (PAVM) embolisation performed using high-frequency jet ventilation (HFJV) as compared with conventional intermittent positive pressure ventilation (IPPV)

Methods

Patients undergoing PAVM embolisation with HFJV assistance after April 2017 were retrospectively identified as group A, and those treated with IPPV before April 2017 as group B. Primary outcomes were patient radiation dose and procedural duration between groups A and B. Secondary outcomes were difference in diaphragmatic excursion between groups A and B, in group A with/without HFJ assistance, technical/clinical success, and complications.

Results

Twelve PAVMs were embolised in 5 patients from group A, and 15 PAVMs in 10 patients from group B. Mean patient radiation was significantly lower in group A than in group B (54,307 ± 33,823 mGy cm² [mean ± standard deviation] versus 100,704 ± 43,930 mGy cm²; p = 0.022). Procedural duration was 33.4 ± 16.1 min in group A versus 57.4 ± 14.9 min in group B (p = 0.062). Diaphragmatic excursion was significantly lower in group A (1.3 ± 0.4 mm) than in group B (19.7 ± 5.2 mm; p < 0.001) and lower with near statistical significance in group A with HFJV than without HFJV (1.3 ± 0.4 mm versus 10.9 ± 3.1 mm; p = 0.062). Technical and clinical success was 100% in both groups, without relevant complications.

Conclusion

HFJV-assisted PAVM embolisation is a safe, feasible technique resulting in reduced patient radiation doses and procedural time.