Hereditary Hemorrhagic Telangiectasia: The Convergence of Genotype, Phenotype, and Imaging in Modern Diagnosis and Management of a Multisystem Disease

De Novo Brain Vascular Malformations in Hereditary Hemorrhagic Telangiectasia

BACKGROUND

Approximately 10% of people with hereditary hemorrhagic telangiectasia (HHT) have brain vascular malformations (VMs). Few reports describe de novo brain VM formation. International HHT Guidelines recommend initial brain VM screening upon HHT diagnosis in children but do not address rescreening. We aimed to confirm whether brain VMs can form de novo in patients with HHT.

METHODS

The Brain Vascular Malformation Consortium HHT project is a 17-center longitudinal study enrolling patients since 2010. We analyzed the database for de novo VMs defined as those detected (1) on follow-up neuroimaging in a patient without previous brain VMs or (2) in a location distinct from previously identified brain VMs and reported those in whom a de novo VM could be confirmed on central neuroimaging review.

RESULTS

Of 1909 patients enrolled, 409 (21%) had brain VMs. Seven patients were recorded as having de novo brain VMs, and imaging was available for central review in four. We confirmed that three (0.7% of individuals with brain VMs) had de novo brain VMs (two capillary malformations, one brain arteriovenous malformation) with intervals of six, nine, and 13 years from initial imaging. Two with de novo brain VMs were <18 years. The fourth patient, a child, did not have a de novo brain VM but had a radiologically confirmed increase in size of an existing brain arteriovenous malformation.

CONCLUSIONS

Brain VMs can, albeit rarely, form de novo in patients with HHT. Given the potential risk of hemorrhage from brain VMs, regular rescreening in patients with HHT may be warranted.

Current Practice: Rationale for Screening Children with Hereditary Hemorrhagic Telangiectasia for Brain Vascular Malformations

BACKGROUND

Hereditary hemorrhagic telangiectasia is an autosomal dominant vascular dysplasia characterized by mucocutaneous telangiectasias, recurrent epistaxis, and organ vascular malformations including in the brain, which occur in about 10% of patients. These brain vascular malformations include high-flow AVMs and AVFs as well as low-flow capillary malformations. High-flow lesions can rupture, causing neurologic morbidity and mortality.

STATE OF PRACTICE

International guidelines for the diagnosis and management of hereditary hemorrhagic telangiectasia recommend screening children for brain vascular malformations with contrast enhanced MR imaging at hereditary hemorrhagic telangiectasia diagnosis. Screening has not been uniformly adopted by some practitioners who contend that screening is not justified. Arguments against screening include application of short-term data from the adult A Randomized Trial of Unruptured Brain Arteriovenous Malformations (ARUBA) trial of unruptured sporadic brain AVMs to children with hereditary hemorrhagic telangiectasia as well as concerns about administration of sedation or IV contrast and causing patients or families increased anxiety.

ANALYSIS

In this article, a multidisciplinary group of experts on hereditary hemorrhagic telangiectasia reviewed data that support screening guidelines and counter arguments against screening. Children with hereditary hemorrhagic telangiectasia have a preponderance of high-flow lesions including AVFs, which have the highest rupture risk. The rupture risk among children is estimated at about 0.7% per lesion per year and is additive across lesions and during a lifetime. ARUBA, an adult clinical trial of expectant medical management versus treatment of unruptured brain AVMs, favored medical management at 5 years but is not applicable to pediatric patients with hereditary hemorrhagic telangiectasia given the life expectancy of a child. Additionally, interventional, radiosurgical, and surgical techniques have improved with time. Experienced neurovascular experts can prospectively determine the best treatment for each child on the basis of local resources. The "watch and wait" approach to imaging means that children with brain vascular malformations will not be identified until a potentially life-threatening and deficit-producing intracerebral hemorrhage occurs. This expert group does not deem this to be an acceptable trade-off.

Monogenic Causes of Cerebrovascular Disease in Childhood: A Case Series

BACKGROUND

Despite an increase in the number of genes associated with pediatric stroke, imaging phenotypes in children have not been well reported. Guidelines are needed to facilitate the identification and treatment of patients with monogenic causes of cerebrovascular disorders.

METHODS

We performed a retrospective review of imaging and medical records of patients aged zero to 21 years with monogenic causes of vascular malformations, small or large vessel disease, transient ischemic attacks, and/or ischemic or hemorrhagic stroke. We classified patients according to their imaging phenotype and reviewed neurological and systemic features and management strategies. We reviewed the literature to identify genes associated with cerebrovascular disorders presenting in childhood.

RESULTS

We identified 18 patients with monogenic causes of cerebrovascular disorders and classified each patient as belonging to one or more of three cerebrovascular phenotypes according to predominant imaging characteristics: small vessel disease, large vessel disease, and/or vascular malformations. Preventative treatments included aspirin, N-acetylcysteine, tocilizumab, therapeutic low-molecular-weight heparin, and resection of vascular malformations.

CONCLUSIONS

Classifying pediatric patients with cerebrovascular disorders by imaging phenotype can aid in determining the next steps in genetic testing and treatment.

Exploring effects of atmospheric conditions in hereditary hemorrhagic telangiectasia

BACKGROUND

Hereditary hemorrhagic telangiectasia (HHT) is a rare autosomal dominant disorder characterized by recurrent epistaxis, telangiectasias, and visceral arteriovenous malformations. Individuals with HHT often identify low humidity and temperature as detrimental to epistaxis severity. We set out to assess the relationship between humidity and temperature on epistaxis severity in patients with HHT.

METHODS

Retrospective cross-sectional study at an academic hospital with an HHT center between July 1, 2014 and January 1, 2022. The primary outcome of this study was ESS. Pearson correlation analyses and multiple linear regression analyses were performed to test the association between weather variables and epistaxis severity scre (ESS). Results were reported as coefficient and 95% confidence interval (CI).

RESULTS

Four hundred twenty-nine patients were included in the analysis. Through a Pearson correlation analysis, neither humidity (regression coefficient = -0.01; 95% CI, -0.006 to 0.003; p = 0.50), daily low temperature (regression coefficient = 0.01; 95% CI, -0.011 to 0.016; p = 0.72), or daily high temperature (regression coefficient = 0.01; 95% CI, -0.004 to 0.013; p = 0.32) were significantly correlated with ESS. In a multiple linear regression analysis, adjusting for both daily low temperature and humidity, medications taken, demographics, and genotype, neither daily low temperature (regression coefficient = -0.02; 95% CI, -0.04 to 0.01; p = 0.14) nor humidity (regression coefficient = 0.01; 95% CI, -0.01 to 0.01; p = 0.64) were significantly associated with ESS.

CONCLUSION

We have shown in a large clinical sample that neither humidity nor temperature were strongly correlated with HHT patient epistaxis severity.

Antiplatelets and antithrombotics in neurointerventional procedures: Guideline update

BACKGROUND

Antiplatelet and antithrombotic medication management before, during, and after neurointerventional procedures has significant practice variation. This document updates and builds upon the 2014 Society of NeuroInterventional Surgery (SNIS) Guideline 'Platelet function inhibitor and platelet function testing in neurointerventional procedures', providing updates based on the treatment of specific pathologies and for patients with specific comorbidities.

METHODS

We performed a structured literature review of studies that have become available since the 2014 SNIS Guideline. We graded the quality of the evidence. Recommendations were arrived at through a consensus conference of the authors, then with additional input from the full SNIS Standards and Guidelines Committee and the SNIS Board of Directors.

RESULTS

The management of antiplatelet and antithrombotic agents before, during, and after endovascular neurointerventional procedures continues to evolve. The following recommendations were agreed on. (1) It is reasonable to resume anticoagulation after a neurointerventional procedure or major bleeding episode as soon as the thrombotic risk exceeds the bleeding risk in an individual patient (Class I, Level C-EO). (2) Platelet testing can be useful to guide local practice, and specific approaches to using the numbers demonstrate marked local variability (Class IIa, Level B-NR). (3) For patients without comorbidities undergoing brain aneurysm treatment, there are no additional considerations for medication choice beyond the thrombotic risks of the catheterization procedure and aneurysm treatment devices (Class IIa, Level B-NR). (4) For patients undergoing neurointerventional brain aneurysm treatment who have had cardiac stents placed within the last 6-12 months, dual antiplatelet therapy (DAPT) is recommended (Class I, Level B-NR). (5) For patients being evaluated for neurointeventional brain aneurysm treatment who had venous thrombosis more than 3 months prior, discontinuation of oral anticoagulation (OAC) or vitamin K antagonists should be considered as weighed against the risk of delaying aneurysm treatment. For venous thrombosis less than 3 months in the past, delay of the neurointerventional procedure should be considered. If this is not possible, see atrial fibrillation recommendations (Class IIb, Level C-LD). (6) For patients with atrial fibrillation receiving OAC and in need of a neurointerventional procedure, the duration of TAT (triple antiplatelet/anticoagulation therapy=OAC plus DAPT) should be kept as short as possible or avoided in favor of OAC plus single antiplatelet therapy (SAPT) based on the individual's ischemic and bleeding risk profile (Class IIa, Level B-NR). (7) For patients with unruptured brain arteriovenous malformations there is no indication to change antiplatelet or anticoagulant management instituted for management of another disease (Class IIb, Level C-LD). (8) Patients with symptomatic intracranial atherosclerotic disease (ICAD) should continue DAPT following neurointerventional treatment for secondary stroke prevention (Class IIa, Level B-NR). (9) Following neurointerventional treatment for ICAD, DAPT should be continued for at least 3 months. In the absence of new stroke or transient ischemic attack symptoms, reversion to SAPT can be considered based on an individual patient's risk of hemorrhage versus ischemia (Class IIb, Level C-LD). (10) Patients undergoing carotid artery stenting (CAS) should receive DAPT before and for at least 3 months following their procedure (Class IIa, Level B-R). (11) In patients undergoing CAS during emergent large vessel occlusion ischemic stroke treatment, it may be reasonable to administer a loading dose of intravenous or oral glycoprotein IIb/IIIa or P2Y12 inhibitor followed by maintenance intravenous infusion or oral dosing to prevent stent thrombosis whether or not the patient has received thrombolytic therapy (Class IIb, C-LD). (12) For patients with cerebral venous sinus thrombosis, anticoagulation with heparin is front-line therapy; endovascular therapy may be considered particularly in cases of clinical deterioration despite medical therapy (Class IIa, Level B-R).

CONCLUSIONS

Although the quality of evidence is lower than for coronary interventions due to a lower number of patients and procedures, neurointerventional antiplatelet and antithrombotic management shares several themes. Prospective and randomized studies are needed to strengthen the data supporting these recommendations.

The Role and Therapeutic Implications of Inflammation in the Pathogenesis of Brain Arteriovenous Malformations

Brain arteriovenous malformations (bAVMs) are focal vascular lesions composed of abnormal vascular channels without an intervening capillary network. As a result, high-pressure arterial blood shunts directly into the venous outflow system. These high-flow, low-resistance shunts are composed of dilated, tortuous, and fragile vessels, which are prone to rupture. BAVMs are a leading cause of hemorrhagic stroke in children and young adults. Current treatments for bAVMs are limited to surgery, embolization, and radiosurgery, although even these options are not viable for ~20% of AVM patients due to excessive risk. Critically, inflammation has been suggested to contribute to lesion progression. Here we summarize the current literature discussing the role of the immune system in bAVM pathogenesis and lesion progression, as well as the potential for targeting inflammation to prevent bAVM rupture and intracranial hemorrhage. We conclude by proposing that a dysfunctional endothelium, which harbors the somatic mutations that have been shown to give rise to sporadic bAVMs, may drive disease development and progression by altering the immune status of the brain.

Identifying racial disparities in hereditary hemorrhagic telangiectasia

BACKGROUND

Hereditary hemorrhagic telangiectasia (HHT) is a rare autosomal dominant disorder characterized by recurrent epistaxis (nose bleeds), mucosal telangiectasias (spider veins), and arteriovenous malformations. Although HHT affects all racial groups, few studies have explored racial disparities among patients with HHT.

METHODS

We performed a retrospective chart review of HHT patients who were seen at a single academic center between July 1, 2014 and January 1, 2022. The primary outcomes of this study were the Epistaxis Severity Score (ESS) and the presence of pulmonary, cerebral, gastrointestinal, spinal, and hepatic arteriovenous malformations (AVMs). We analyzed racial differences using t-tests and analysis of variance (ANOVA) for continuous variables, and chi-squared tests for categorical variables. We then performed multivariable linear and logistic regressions on outcomes.

RESULTS

Our review identified 35 Asian, 6 Black or African American, 72 Hispanic or Latino, and 244 White or Caucasian patients who met the inclusion criteria. Through an analysis of variance model, race/ethnicity was not significantly associated with ESS. Two univariable logistic regression models between race and both pulmonary and brain AVMs showed that race was associated with the incidence of pulmonary AVMs (p<0.01), with Asian patients at a 2.3-fold increased risk of pulmonary AVMs compared with White patients (p=0.03). Race was also associated with the incidence of cerebral AVMs (p<0.01) with Hispanic or Latino patients at a 4.8-fold increased risk compared with White patients (p<0.01).

CONCLUSION

Patients who identified as Asian may have higher rates of pulmonary AVMs while patients identifying as Hispanic or Latino may have more cerebral AVMs. The correlations may be important for identifying risk factors in certain patient populations.

Laparoscopic Double Hepatic Artery Banding/Ligation for Patients With Hepatic Hereditary Haemorrhagic Telangiectasia (HHHT)

Introduction

Hepatic hereditary haemorrhagic telangiectasia (HHHT) is a rare autosomal dominant genetic disease. Some patients may develop cardiac failure, portal hypertension, and biliary ischaemia. To date, there is no standard surgical treatment for HHHT. The present authors propose a move from open to laparoscopic surgery; however, laparoscopic surgery has not been reported previously as a surgical treatment for HHHT.

Report

Two women were admitted with histories of exertional dyspnoea and upper abdominal pain, respectively. Combined with recurrent epistaxis and their positive family history, a diagnosis of clinical HHHT was made based on Curacao criteria after comprehensive evaluation of imaging features. Next generation sequencing (NGS) results also confirmed typical gene mutations responsible for HHT. Both patients underwent laparoscopic double hepatic artery banding and or ligation successfully and were discharged four to six days after operation without severe complications. The symptoms of cardiac insufficiency including exertional dyspnoea and shortness of breath of the first patient improved six months after the operation. The second patient, with epigastric pain, remained pain free without medication three months after the operation.

Discussion

Laparoscopic surgery for HHHT is technically challenging. Clinical data and follow up information showed that laparoscopic double hepatic artery banding and or ligation was a technically feasible surgical approach for HHHT patients with simple hepatic artery dilation.

Hereditary Hemorrhagic Telangiectasia in a Young Adult: Gastrointestinal Arteriovenous Malformations as a Presenting Feature

Hereditary hemorrhagic telangiectasia (HHT) is characterized by the presence of multiple arteriovenous malformations (AVM) in which arteries and venules are connected directly without intervening capillaries. The primary clinical presentation is spontaneous and recurrent nosebleeds (epistaxis), typically starting around 12. Telangiectases, which are small arteriovenous malformations, are commonly found in mucocutaneous areas and gastrointestinal (GI) mucosa. The presentation of epistaxis precedes the occurrence of telangiectases. Larger AVMs most commonly affect the lungs, liver, or brain, and complications from bleeding or shunting can be potentially life-threatening. Here, we discuss the case of a 44-year-old man who presented to the emergency department with a chief complaint of fatigue for three weeks associated with shortness of breath. His eventual labs revealed severe anemia with a hemoglobin of 4.4 g/dL. He denied any history of symptoms of GI bleeding. Computed tomography of the abdomen was done which did not reveal any intra-abdominal bleeding, hematoma, or abnormality. Further history revealed a recent diagnosis of HHT in his mother through genetic testing. During the stay, he also developed spontaneous epistaxis which was treated with topical vasoconstrictors by the ear, nose, and throat (ENT) physician. Given the high likelihood of HHT, he underwent luminal evaluation. Upper and lower endoscopies of the gut revealed multiple AVMs. A diagnosis of HHT was established as he fulfilled the criteria required for the diagnosis of HHT. It is rare for individuals with HHT to experience GI bleeding before the age of 50, making this case unique.

Unsupervised machine learning algorithms identify expected haemorrhage relationships but define unexplained coagulation profiles mapping to thrombotic phenotypes in hereditary haemorrhagic telangiectasia

Hereditary haemorrhagic telangiectasia (HHT) can result in challenging anaemia and thrombosis phenotypes. Clinical presentations of HHT vary for relatives with identical casual mutations, suggesting other factors may modify severity. To examine objectively, we developed unsupervised machine learning algorithms to test whether haematological data at presentation could be categorised into sub-groupings and fitted to known biological factors. With ethical approval, we examined 10 complete blood count (CBC) variables, four iron index variables, four coagulation variables and eight iron/coagulation indices combined from 336 genotyped HHT patients (40% male, 60% female, 86.5% not using iron supplementation) at a single centre. T-SNE unsupervised, dimension reduction, machine learning algorithms assigned each high-dimensional datapoint to a location in a two-dimensional plane. k-Means clustering algorithms grouped into profiles, enabling visualisation and inter-profile comparisons of patients' clinical and genetic features. The unsupervised machine learning algorithms using t-SNE and k-Means identified two distinct CBC profiles, two iron profiles, four clotting profiles and three combined profiles. Validating the methodology, profiles for CBC or iron indices fitted expected patterns for haemorrhage. Distinct coagulation profiles displayed no association with age, sex, C-reactive protein, pulmonary arteriovenous malformations (AVMs), ENG/ACVRL1 genotype or epistaxis severity. The most distinct profiles were from t-SNE/k-Means analyses of combined iron-coagulation indices and mapped to three risk states - for venous thromboembolism in HHT; for ischaemic stroke attributed to paradoxical emboli through pulmonary AVMs in HHT; and for cerebral abscess attributed to odontogenic bacteremias in immunocompetent HHT patients with right-to-left shunting through pulmonary AVMs. In conclusion, unsupervised machine learning algorithms categorise HHT haematological indices into distinct, clinically relevant profiles which are independent of age, sex or HHT genotype. Further evaluation may inform prophylaxis and management for HHT patients' haemorrhagic and thrombotic phenotypes.

A case report of isolated right ventricular noncompaction with mutation of ACVRL1: a new cause of noncompaction of ventricular myocardium?

BACKGROUND

Noncompaction of ventricular myocardium(NVM) is a rare kind of cardiomyopathy associated with genetic mutations and nongenetic factors, among which the isolated right ventricular noncompaction (iRVNC) is the most rare type. ACVRL1 is the pathogenic gene of type 2 hereditary hemorrhagic telangiectasia (HHT2), and there's no NVM reported to be associated with ACVRL1 mutation.

CASE PRESENTATION

This is a rare case diagnosed as iRVNC and pulmonary hypertention with ACVRL1 mutation detected.

CONCLUSION

iRVNC in this case may be due to ACVRL1 mutation, secondary to pulmonary hypertention and right ventricular failure caused by ACVRL1 mutation, or they happened in the same case coincidently.

Application of contrast-enhanced ultrasound in hemothorax of hereditary hemorrhagic telangiectasia: A case report and literature review

Hereditary hemorrhagic telangiectasis (HHT) is an autosomal dominant hereditary disease, which can lead to abnormal angiogenesis. We performed contrast-enhanced ultrasound (CEUS) in a patient with HHT represented with hemothorax. After targeted embolization, the condition of hemothorax improved. In this case, we explore the use of CEUS to locate the responsible vessel of hemothorax, and found that CEUS could be used as a complementary preoperative method of localization with Computed tomography angiography (CTA).

Case report: Diagnosis of hereditary hemorrhagic telangiectasia (Osler Weber Rendu Syndrome) in a 23-year-old male presented with anemia and thrombocytopenia and its response to bevacizumab

Osler Weber Rendu Syndrome (OWS) is characterized by the development of abnormally dilated blood vessels, which manifest as arteriovenous shunts (pulmonary, gastrointestinal, hepatic, and cerebral) and mucocutaneous telangiectasias (lips, tongue, and fingertips). It is an autosomal dominant disease with a defect in transforming growth factor beta superfamily genes. This defect results in increased angiogenesis and disruption of vessel wall integrity. The disease remains underreported, with occasional history of recurrent epistaxis, iron deficiency anemia, and gastrointestinal bleeding in moderate to severe cases. Diagnosis is based on clinical presentation and confirmed by genetic testing. Various local (nasal saline, air humidification, laser ablation, and electric cauterization for epistaxis and endoscopic Argon Plasma Coagulation-APC for active GI bleeding), surgical, and systemic (tranexamic acid and antiangiogenic agents like bevacizumab and thalidomide) treatment options are used depending upon disease severity. Here, we present a case with recurrent gastrointestinal bleeding refractory to endoscopic APC ablation and thalidomide and severe symptomatic anemia requiring multiple packed red cell transfusions. The patient was ultimately started on bevacizumab, to which he had a good response and has remained in remission for 8 months as of now. This case emphasizes the need to have a low threshold of suspicion to diagnose HHT and start targeted therapy like bevacizumab early on in moderate to severe cases of HHT rather than just relying on temporizing palliative measures like ablation, cauterization, and tranexamic acid.

Rendú Osler Weber Syndrome; case report

Hereditary hemorrhagic telangiectasia (HHT), or Rendu-Osler-Weber disease, is a dominant autosomal disease characterized by the presence of multiple telangiectasia in skin and mucus, associated with arteriovenous malformations (AVM) of various organs, including the lungs, gastrointestinal system and brain. HHT is presented most frequently as recurrent, spontaneous epistaxis. Patients may also present digestive, pulmonary and intracranial hemorrhage, as well as secondary anemia.

This article reports the case of a female patient, 62 years old, with multiple episodes of epistaxis and vaginal bleeding, with diagnosis of complex HHT, which was managed with multiple embolizations, which improved symptoms and survival. In this kind of patient, it is possible, with timely diagnosis and treatment, to obtain a greater quality and expectation of life. Due to the fact that the severity and alterations in each patient are so variable, management should be individualized.

Case Report: Clinical characteristics and genetic analysis of two patients with hereditary hemorrhagic telangiectasia

Objective: To analyze the clinical features and genetic characteristics of two patients with hereditary hemorrhagic telangiectasia (HHT) and to review the relevant literature.

Methods: The clinical data of two HHT patients admitted to the author’s hospital between April 2019 and February 2022 were retrospectively analyzed. Meanwhile, the genetic analysis was performed with their consent.

Results: The first patient was a 62-year-old woman who had been complaining of shortness of breath and fever for 20 days. Her previous medical history included brain abscess drainage and video-assisted thoracoscopic surgery for a pulmonary hemangioma. A right heart catheterization revealed no pulmonary arterial hypertension, and an abdominal enhanced magnetic resonance imaging revealed multiple arteriovenous malformations in the liver. Her ACVRL1 heterozygous variants were discovered through whole-exon gene testing. The second case involved a 47-year-old woman who had been experiencing chest tightness for the past 2 years. Several years ago, she underwent brain abscess drainage and embolization of a pulmonary arteriovenous fistula. Ultrasound revealed generalized hepatic vascular dilation, and enhanced computed tomography revealed numerous pulmonary venous fistulas scattered in both lungs as well as multiple arteriovenous malformations in the liver. Her whole-exon gene testing revealed that she, like her son, had heterozygous ENG variants.

Conclusion: HHT patients may experience infection, bleeding, dyspnea, and other symptoms. Imaging is important in disease diagnosis and management because early detection and treatment can prevent major complications and disability or even death.

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.