Endothelial-to-Mesenchymal Transition in an Hereditary Hemorrhagic Telangiectasia-like Pediatric Case of Multiple Pulmonary Arteriovenous Malformations.

Pulmonary arteriovenous malformations (PAVMs) are vascular anomalies resulting in abnormal connections between pulmonary arteries and veins. In 80% of cases, PAVMs are present from birth, but clinical manifestations are rarely seen in childhood. These congenital malformations are typically associated with Hereditary Hemorrhagic Telangiectasia (HHT), a rare disease that affects 1 in 5000/8000 individuals. HHT disease is frequently caused by mutations in genes involved in the TGF-ß pathway. However, approximately 15% of patients do not have a genetic diagnosis and, among the genetically diagnosed, more than 33% do not meet the Curaçao criteria. This makes clinical diagnosis even more challenging in the pediatric age group. Here, we introduce an 8-year-old patient bearing a severe phenotype of multiple diffuse PAVMs caused by an unknown mutation which ended in lung transplantation. Phenotypically, the case under study follows a molecular pattern which is HHT-like. Therefore, molecular- biological and cellular-functional analyses have been performed in primary endothelial cells (ECs) isolated from the explanted lung. The findings revealed a loss of functionality in lung endothelial tissue and a stimulation of endothelial-to-mesenchymal transition. Understanding the molecular basis of this transition could potentially offer new therapeutic strategies to delay lung transplantation in severe cases.

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.

Adult Partial Anomalous Pulmonary Venous Connection: Case Reports (Including a Case of Scimitar Syndrome).

Partial anomalous pulmonary venous connection (PAPVC) is a congenital heart defect in which one or more pulmonary veins drain abnormally into the systemic venous circulation, leading to the development of pulmonary arterial hypertension. It can be supracardiac type, draining into the superior vena cava or right atrium (also called cardiac type) and infracardiac type with drainage into the inferior vena cava (IVC). We present two cases-supracardiac and infracardiac types of PAPVC in this case report.

TAPVR: Molecular Pathways and Animal Models.

The venous pole of the heart where the pulmonary veins will develop encompasses the sinus venosus and the atrium. In the fourth week of development, the sinus venosus consists of a left and a right part receiving blood from the common cardinal vein, the omphalomesenteric and umbilical veins. Asymmetrical expansion of the common atrium corresponds with a rightward shift of the connection of the sinus to the atrium. The right-sided part of the sinus venosus including its tributing cardinal veins enlarges to form the right superior and inferior vena cava that will incorporate into the right atrium. The left-sided part in human development largely obliterates and remodels to form the coronary sinus in adults. In approximately the same time window (4th-fifth weeks), a splanchnic vascular plexus surrounds the developing lung buds (putative lungs) with a twofold connection. Of note, during early developmental stages, the primary route of drainage from the pulmonary plexus is toward the systemic veins and not to the heart. After lumenization of the so-called mid-pharyngeal endothelial strand (MPES), the first anlage of the pulmonary vein, the common pulmonary vein can be observed in the dorsal mesocardium, and the primary route of drainage will gradually change toward a cardiac drainage. The splanchnic pulmonary venous connections with the systemic cardinal veins will gradually disappear during normal development. In case of absence or atresia of the MPES, the pulmonary-to-systemic connections will persist, clinically resulting in total anomalous pulmonary venous return (TAPVR). This chapter describes the developmental processes and molecular pathways underlying anomalous pulmonary venous connections.

Clinical Presentation and Therapy of Total Anomalous Pulmonary Venous Return.

Total anomalous pulmonary venous return (TAPVR) is rare (accounting for about 1% of all CHD) and can occur as a single lesion or in combination with other types of CHD (such as heterotaxy or HLHS). TAPVR is defined as an abnormal connection where all pulmonary veins do not drain into the left atrium but into the right atrium either directly or through a vein that is connected to the right atrium. TAPVR can be divided into four anatomic groups (Fig. 32.1): (1) supracardiac (about 55%), (2) cardiac (about 30%), (3) infracardiac (about 13%), and (4) mixed (very rare). In addition, it can be divided into two physiological types: nonobstructed and obstructed. Embryologically, all pulmonary veins usually connect to a pulmonary venous confluence that connects to the left atrium. If this connection does not occur, the pulmonary venous confluence connects to a systemic vein instead.

Inflow Tract Development.

The development of the inflow tract is undoubtedly one of the most complex remodeling events in the formation of the four-chambered heart. It involves the creation of two separate atrial chambers, the formation of an atrial/atrioventricular (AV) septal complex, the incorporation of the caval veins and coronary sinus into the right atrium, and the remodeling events that result in pulmonary venous return draining into the left atrium. In these processes, the atrioventricular mesenchymal complex, consisting of the major atrioventricular (AV) cushions, the mesenchymal cap on the primary atrial septum (pAS), and the dorsal mesenchymal protrusion (DMP), plays a crucial role.

Total Anomalous Pulmonary Venous Connections, Human Genetics.

Partial anomalous pulmonary venous connections (PAVC) have been found after abnormal gene expressions involving several syndromes. Total anomalous pulmonary venous connection (TAPVC) is found in conjunction with heterotaxia syndrome as well as several other syndromes. It has been reported with an autosomal dominance with variable expression and incomplete penetrance. The occurrence is also related to environmental factors which may superimpose on a familial susceptibility for TAPVC. Many pathways are involved in the normal development of the pulmonary venous connections and as a consequence disturbance of many genetic and epigenetic pathways lead to partial or total pulmonary venous misconnections. In this chapter, an overview of current knowledge regarding human genetics of anomalous venous connections is provided.

Massive hemothorax induced by pulmonary arteriovenous malformation rupture: a case report and literature review.

BACKGROUND: Pulmonary arteriovenous malformation (PAVM), also known as pulmonary arteriovenous fistula, is a rare vascular developmental anomaly. Most cases of PAVM are associated with hereditary hemorrhagic telangiectasia (HHT). Hemothorax associated with PAVM is even rarer, and management concerning this complication still challenges. CASE PRESENTATION: A 55-year-old man with sudden onset of dyspnea and chest pain was admitted to our hospital. He had a medical history of epistaxis, intraperitoneal germ cell tumor and PAVM. Chest unenhanced CT revealed the left-sided pleural effusion together with partial passive atelectasis and gradual increase at the interval of six days. Diagnostic thoracocentesis further revealed hemorrhagic effusion. CT angiography (CTA) showed tortuously dilated lumen of the left lower pulmonary artery and PAVM with the formation of aneurysm. Due to his family's refusal of surgery, the patient underwent transcatheter embolization therapy. However, the left pleural effusion did not significantly reduce and there was a slow drop in hemoglobin value even after interventional treatment, indicating the possibility of ongoing active bleeding. Eventually, the patient received lobectomy of the left lower lobe with a satisfactory outcome. CONCLUSIONS: Massive hemothorax resulting from PAVM rupture into the pleural space can lead to fatal outcomes. CTA can accurately diagnose this pathologic condition. Transcatheter embolization is frequently used in the treatment of PAVM, but it may be challenging to achieve the desirable effect in patients with hemothorax. Combined with our case and literature review, direct radical surgery can lead to a successful outcome when PAVM complicated with hemothorax and a large diameter of the draining vein.

Scimitar syndrome with vein stenosis in an infant.

Scimitar syndrome is characterised by right lung hypoplasia and abnormal pulmonary venous return, known as the 'scimitar vein'. We report the case of an infant girl with scimitar syndrome who developed a severe respiratory distress mimicking asthma. Pulmonary hypertension (PH) was diagnosed, attributed to scimitar vein stenosis and a left-to-right shunt. Scimitar vein stenosis, a rare complication of scimitar syndrome, can lead to severe PH, highlighting the importance of prompt management in specialised care centres.

[Thymoma with Partial Anomalous Pulmonary Venous Drainage from the Left Upper Lobe:Report of a Case].

A 73-year-old woman presented with left anterior chest pain and back pain. Computed tomography (CT) scan showed an anterior mediastinal tumor. It also showed partial anomalous pulmonary venous drainage (left superior pulmonary vein draining into the left brachiocephalic vein), and the tumor was located near the left brachiocephalic vein. The operation was performed through a median sternotomy to resect the thymus and tumor with partial resection of the left upper lobe due to the tumor's adhesion to the left upper lobe. One of the vascular anomalies encountered in adult thoracic surgery is partial anomalous pulmonary venous drainage. It is important to recognize the presence of such an anomaly on imaging and to anticipate the surgical procedure with a preoperative surgical technique.

Factors associated with early postoperative mortality after total anomalous pulmonary venous connection repair: A retrospective cohort study.

Total anomalous pulmonary venous connection (TAPVC) is a rare congenital defect where pulmonary venous plexus fails to connect with the left atrium (LA). Surgical repair is the primary treatment for TAPVC, but factors influencing outcomes are not fully understood. This study investigates the early outcomes of surgical repair for TAPVC and associated factors. A retrospective cohort analysis was conducted on TAPVC patients who underwent surgical repair between 2012 and 2022. Data were collected from medical records and supplemented with phone call validation. Demographic characteristics, surgical data, diagnostic tests, and outcomes were analyzed. Statistical analysis included chi-square, t-tests, and multivariate logistic regression using SPSS. A total of 88 patients underwent surgical repair for TAPVC, resulting in a mortality rate of 21.6%. Weight and bypass time were significantly associated with patient survival. Female patients had a higher likelihood of death. The anatomic type did not significantly influence mortality. Patients with pulmonary venous obstruction (PVO) experienced a higher mortality rate. Notably, ligation of the vertical vein in supracardiac and infracardiac types was associated with lower mortality. In conclusion, our study identifies several key factors contributing to higher mortality rates following TAPVC surgery, including low weight, female gender, prolonged bypass time, and preoperative vein obstruction. Highlighting the significance of surgical technique, particularly the sutureless approach, we advocate for its meticulous consideration to achieve improved outcomes. Furthermore, our findings indicate a potential decrease in mortality associated with vertical vein ligation, which may mitigate the risk of post-repair heart failure. We suggest further rigorous studies to gain comprehensive insights into TAPVC surgical interventions.

A pulmonary artery was embolized in a patient with an occluded pulmonary vein to manage massive hemoptysis.

BACKGROUND: Stenosis and obliteration of the pulmonary vein can be developed by multiple diseases and might cause hemoptysis. Traditional therapy including surgical procedure and conservative treatments might be inappropriate choices to manage massive hemoptysis. CASE PRESENTATION: A 64-year-old man, diagnosed with advanced stage IVA lung squamous cell carcinoma, presented with dyspnea and recurrent, massive hemoptysis. An initial contrast-enhanced computed tomography revealed a giant tumor in the left lung hilus and occlusion of the left superior pulmonary vein. Despite immediate selective bronchial artery embolization and simultaneous embolization of an anomalous branch of the internal thoracic artery, the massive hemoptysis continued. Subsequently, embolization of the left superior pulmonary artery was performed, achieving functional pulmonary lobectomy, which successfully treated the hemoptysis without relapse during a six-month follow-up. The patient continues to undergo cancer therapy and remains stable. CONCLUSIONS: This case successfully managed massive hemoptysis associated with lung cancer invasion into the pulmonary vein through functional pulmonary lobectomy via embolization of the corresponding pulmonary artery.

Total Anomalous Pulmonary Venous Connection in Adults: Should We Offer Surgery?

Background: We aim to determine the surgical outcomes of adult patients with total anomalous pulmonary venous connection (TAPVC) and examine the regression of pulmonary artery (PA) pressures after the procedure. Methods: We reviewed the hospital records from 2003 to 2022 and identified 49 adult patients with TAPVC. We assessed their surgical outcomes and the trend of PA pressures after the procedure. Continuous data are presented as mean ± SD or median (interquartile range) and categorical variables are presented as percentages. Results: The median age of the patients was 23 years (range 18-42) and 31 (63.3%) were male. Thirty-six patients (73.5%) had supracardiac TAPVC. The mean systolic PA pressure was 65.8 ± 16.4 mm Hg and it decreased by 47.9% (34%, 61.8%) after surgery. Moderate or more tricuspid regurgitation was seen in 27 (55.1%) patients before surgery; however, it was present in only 3 (6.1%) patients during early follow-up. There was no intraoperative or 30-day mortality, and the median hospital length of stay was six days. Long-term follow-up data were available for 29 patients with the average duration of follow-up being 5.6 years (range 6 months to 15 years) and the mean systolic PA pressures of this cohort was 29.8±7.9 mm Hg. Forty-six (93.1%) patients were asymptomatic; four women had uneventful pregnancies and delivered healthy children. Conclusion: Surgical repair of the naturally selected group of adult TAPVC patients can be performed safely with good results. Regression in flow-related pulmonary hypertension and an improvement in functional quality of life are seen in nearly all patients.

Isolated Partial Anomalous Pulmonary Veins: A 10-Year Experience at a Single Center.

INTRODUCTION: Isolated partial anomalous pulmonary venous connection (PAPVC) is difficult to diagnose, and surgical indications remain controversial. We reviewed 10 y of isolated PAPVC cases. METHODS: The data of patients with isolated PAPVC admitted to the Anzhen Congenital Heart Disease Department from 2010 to 2019 were reviewed retrospectively. RESULTS: Thirty patients, aged between 4 mo and 32 y, were included in this study. Significant correlations were found between the right ventricle (RV), end-diastolic dimension Z-score (RVED-z) and age (r = 0.398, P = 0.03), and between estimated pulmonary pressure and age (r = 0.423, P = 0.02). However, no significant correlations were found between the RVED-z and the number of anomalous pulmonary veins (r = 0.347, P = 0.061), between estimated pulmonary pressure and the RVED-z (r = 0.218, P = 0.248), and between estimated pulmonary pressure and the number of anomalous veins (r = 0.225, P = 0.232). Transthoracic echocardiography (TTE) confirmed 90% of isolated PAPVC cases. Surgical repair was performed in 29 patients with RV enlargement, persistent low weight, pulmonary hypertension, or respiratory symptoms. Among the surgical patients, nine had elevated pulmonary pressure before surgery, which decreased postoperatively; no mortality or reintervention was observed. The mean duration of echocardiographic follow-up was 1.9 y. CONCLUSIONS: TTE is recommended for routine assessments, and further clarification can be obtained with computed tomography when TTE proves inconclusive for diagnosis. Transesophageal echocardiography and computed tomography are further recommended for adult patients if TTE fails to provide clear results. PAPVC should be considered as an underlying cause when unexplained RV enlargement is observed. Surgery is recommended for patients with RV enlargement, pulmonary hypertension, or respiratory symptoms.

[Ischemic stroke due to paradoxical embolism through pulmonary arteriovenous malformation in a young patient]. / ACV isquémico debido a embolia paradojal a través de malformación arteriovenosa pulmonar en paciente joven.

Paradoxical embolism due to an isolated pulmonary arteriovenous malformation (PAVM) is a rare cause of ischemic stroke. PAVMs are abnormal high-flow connections between pulmonary arteries and veins, diverting deoxygenated blood into the systemic circulation and they represent a less common source of paradoxical embolisms, especially in young individuals. Endovascular embolization is the preferred treatment for clinically significant PAVMs. We present the case of a 34-year-old woman with a left thalamic ischemic stroke. Severe contrast passage was detected in cerebral arteries through transcranial Doppler. Intracardiac ultrasound did not reveal a patent foramen ovale, prompting further investigation with pulmonary CT angiography, confirming the presence of PAVM. The patient underwent successful endovascular treatment. It is essential to consider PAVM in the etiological diagnosis of ischemic stroke, especially in young patients with signs of abnormal right-to-left communication. Periodic follow-up imaging is recommended to assess potential recurrence or changes in PAVM, emphasizing the importance of appropriate management of these malformations.

La embolia paradojal debido a una malformación arteriovenosa pulmonar (MAVP) aislada es una causa infrecuente de accidente cerebrovascular (ACV) isquémico. Las MAVP son conductos anómalos de alta circulación entre arterias y venas pulmonares, desviando sangre desoxigenada hacia la circulación sistémica y representan una fuente menos común de embolias paradojales, especialmente en personas jóvenes. La embolización endovascular es el tratamiento preferido para MAVP clínicamente significativas. Presentamos el caso de una mujer de 34 años con ACV isquémico talámico izquierdo. Se detectó pasaje de burbujas "en cortina" en arterias cerebrales mediante Doppler transcraneal. En ecografía intracardíaca no se encontró foramen oval permeable, motivo por el cual se avanzó con realización de angiotomografía pulmonar, la cual confirmó la presencia de MAVP. La paciente recibió tratamiento endovascular exitoso. Es esencial considerar la MAVP en el diagnóstico etiológico del ACV isquémico, especialmente en pacientes jóvenes con signos de comunicación anormal de derecha a izquierda. Se recomienda un seguimiento periódico mediante imágenes para evaluar la posible recurrencia o cambios en la MAVP, resaltando la importancia del manejo adecuado de estas malformaciones.

Rare and potentially lethal case of a round lesion in the lung.

A pulmonary venous aneurysm (PVA) is extremely rare. A PVA can be either congenital or acquired. Possible symptoms include thoracic pain, dyspnoea, haemoptysis and palpitations but can also occur asymptomatically. Treatment can be conservative or surgical depending on growth and risk of rupture or development of mitral insufficiency, symptoms and thrombus formation. Only a few cases have been described in the literature. A recent case study and a literature review are described below.

Personalised stroke evaluation and management: tailoring individualised patient care for hereditary haemorrhagic telangiectasia.

SummaryHereditary haemorrhagic telangiectasia (HHT) has an estimated prevalence of 1 in 5000-8000 individuals globally with pulmonary arteriovenous malformations (PAVMs) affecting approximately 15%-50% of HHT patients. Ischaemic stroke is a known complication of PAVMs that affects ≤30% of patients with PAVMs. Studies have shown that patients with PAVMs have ischaemic stroke a decade earlier than routine stroke. The predominant mechanism of ischaemic stroke in HHT patients is paradoxical embolism due to PAVMs, but most HHT-related PAVMs are asymptomatic. Additionally, HHT is often underdiagnosed in patients and poses a challenge to physicians due to its rarity. We present a case of a patient with ischaemic stroke who was subsequently diagnosed with HHT and found to have a PAVM on further evaluation. This case highlights the importance of using an individualised patient-centred stroke evaluation and screening for PAVMs in patients who had a stroke with possible or suspected HHT and definite HHT.

Prenatal diagnosis of pulmonary arteriovenous malformations with a postnatal diagnosis of Osler-Weber-Rendu syndrome.

Hereditary Hemorrhagic Telangiectasia (HHT), commonly known as Osler-Weber-Rendu disease, is an autosomal dominant multisystemic vascular disease associated with approximately 70% of cases of pulmonary arteriovenous malformations (PAVMs). Prenatal cases of PAVMs typically present with pulmonary vein dilatation on ultrasonography. This study presents a prenatal diagnosis of PAVMs with enlarged right pulmonary vein, cardiomegaly, cystic-appearing areas in the right lung and subsequent confirmation of Osler-Weber-Rendu syndrome using autopsy and whole exom sequencing.