Prevalence of pulmonary arteriovenous malformations (PAVMs) and occurrence of neurological symptoms in patients with hereditary haemorrhagic telangiectasia (HHT)

High risk of ischaemic stroke amongst patients with hereditary haemorrhagic telangiectasia

BACKGROUND AND PURPOSE

Hereditary haemorrhagic telangiectasia (HHT) is a genetic disease with fragile blood vessels and vascular malformations, potentially causing neurological manifestations, including stroke and cerebral abscesses. The study aimed to investigate neurological manifestations in the Danish HHT database, focusing on pulmonary arteriovenous malformations (PAVMs) as a risk factor for cerebral events.

METHODS

Retrospective analysis of the Danish HHT database was conducted, cross-referencing neurological outcomes with the Danish Apoplexy Register for accuracy. Patients were stratified by HHT type. Primary outcomes included ischaemic stroke, transient ischaemic attack and cerebral haemorrhage. Secondary outcomes comprised age, age at HHT diagnosis, age at cerebral ischaemic event, and PAVM and cerebral arteriovenous malformation status.

RESULTS

Six hundred and sixty-four HHT patients were included. PAVM was diagnosed in 54% of patients, with higher prevalence in HHT type 1 (70%) compared to HHT type 2 (34%) and juvenile polyposis HHT (66%). Ischaemic stroke or transient ischaemic attack occurred in 12.5%, with a higher risk associated with macroscopic PAVM. Logistic regression showed a nearly 10 times increased risk of ischaemic stroke with macroscopic PAVM. Cerebral abscesses occurred in 3.2% of patients, all with macroscopic PAVM. Incomplete PAVM closure increased cerebral abscess risk.

CONCLUSION

This study provides valuable insights into the prevalence of neurological manifestations and vascular events in HHT patients. The presence of PAVM was associated with an increased risk of ischaemic stroke, highlighting the importance of early screening and intervention. The findings emphasize the need for comprehensive management strategies targeting both vascular and neurological complications in HHT patients, especially regarding secondary stroke prevention.

Kidney Transplant Recipient With Cerebral Paradoxical Embolism Following Recurrent Idiopathic Deep Vein Thrombosis and Pulmonary Embolism: Case Report and Review of the Literature

Paradoxical embolism occurs when a thrombus crosses an intracardiac defect into the systemic circulation. Here, we present the case of a 35-yearold male kidney transplant recipient with a cerebral paradoxical embolism associated with a spontaneous venous thromboembolism. This patient had recurrent deep venous thrombosis and showering emboli to the lung and paradoxically to the brain through patent foramen ovale, and we treated him successfully. The role of bubble echocardiography was essential in diagnosis to avoid contrast-induced nephropathy. This is the first successfully managed case of a kidney transplant recipient with recurrent idiopathic deep vein thrombosis, pulmonary embolism, and cerebral paradoxical embolism. Bubble echocardiography was an excellent alternative to contrast angiography to avoid nephrotoxicity. Vitamin K antagonists are superior to direct oral anticoagulants, especially among nonadherent/noncompliant patients.

Oral manifestations and dental considerations of patients with hereditary hemorrhagic telangiectasia: a scoping review

OBJECTIVE

We examined the range, nature, and extent of research conducted regarding the oral and dental implications of hereditary hemorrhagic telangiectasia (HHT) to identify gaps in the research and knowledge of the field.

STUDY DESIGN

We performed a scoping review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews and 2017 Guidance for the Conduct of Joanna Briggs Institute Scoping Reviews. We searched the MEDLINE and Web of Science databases for all full-text articles published in English from December 1946 to October 2022.

RESULTS

We identified 103 articles describing oral and dental considerations of patients with HHT, primarily case reports. Most reported oral telangiectasias of the tongue, lips, and palate. Many reported management of bleeding and the use or recommendation of prophylactic antibiotics before dental procedures.

CONCLUSIONS

Oral telangiectasias are commonly found in patients with hereditary hemorrhagic telangiectasia, and dental professionals may be the first to diagnose it in their patients. Early detection and diagnosis are important to prevent potentially fatal outcomes, and prophylactic antibiotics before procedures may be warranted.

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.

Evolution of Pulmonary Arteriovenous Malformations: The Role of Contrast Echocardiography

BACKGROUND

Pulmonary arteriovenous malformations (PAVMs) are direct connections between the pulmonary artery and the pulmonary vein, mostly associated with hereditary hemorrhagic telangiectasia (HHT). PAVMs can lead to severe neurologic complications such as stroke and brain abscess. The risk of complications decreases after embolization. Therefore, screening for PAVMs using transthoracic contrast echocardiography (TTCE) is recommended, including a rescreening interval of 5 years.

RESEARCH QUESTION

Is extension of the interval for rescreening patients without a pulmonary right-to-left shunt (RLS) of up to 10 years appropriate?

STUDY DESIGN AND METHODS

Adult patients with HHT with 5- or 10-year follow-up TTCE, or both, were included. Patients who underwent PAVM embolization in the past or at baseline were excluded. The RLS grades and presence of a treatable PAVM were compared with baseline.

RESULTS

In total, 387 patients (median age, 45 years [interquartile range, 33-54 years]; 56% women) involving 5- and 10-year follow-up data in 363 and 166 patients, respectively, were included. None of the patients (n = 148) without a pulmonary RLS at baseline demonstrated a treatable PAVM after 5 and 10 years. Of the patients with a pulmonary RLS at baseline, 20 patients (9%) and three patients (3%) demonstrated a treatable PAVM at the 5- and 10-year follow-up, respectively. In most patients, the RLS grade remained stable over time.

INTERPRETATION

On the basis of the results of this retrospective study, we believe that the rescreening interval for patients with HHT without a pulmonary RLS at initial screening may be extended to 10 years. Those with a pulmonary RLS should be rescreened every 5 years because treatable PAVMs can evolve.

Endovascular management of pulmonary arteriovenous malformations presenting as multiple brain abscesses

Pulmonary arteriovenous malformations (PAVMs) are rare vascular lesions characterised by abnormal connections between the pulmonary artery and vein bypassing the pulmonary capillary bed and causing right-to-left shunt. Paradoxical embolism is known to occur in these cases, leading to inoculation of septic focus in the systemic circulation. We report a case of multiple PAVMs who presented clinically with seizures and altered sensorium. On radiological work-up, multiple brain abscesses and large PAVMs were evident. The patient was successfully treated by endovascular embolisation of the PAVMs using a vascular plug and multiple coils. The patient showed complete clinical recovery and resolution of brain abscesses on follow-up.

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.

Wide-ranging clinical spectrum of paradoxical embolism

The purpose of this review is to raise the index of suspicion for paradoxical embolism among generalists. The review is based solely on anecdotal reports compiled from EMBASE, MEDLINE, Googlescholar and Pubmed. Search terms were 'paradoxical embolism', 'pulmonary embolism' and 'pulmonary arteriovenous malformations'. What emerged was that right-to-left paradoxical embolism could occur with or without concurrent pulmonary embolism, and also with and without proof of the presence of an 'embolus-in-transit'. Potential sites of single or multiple systemic involvement included the central nervous system, the coronary circulation, renal arterial circulation, splenic circulation, the mesenteric circulation and the limbs. In many cases, the deep veins of the lower limbs were the source of thromboembolism. In other cases, thrombi originated from an atrial septal aneurysm, from a central venous line, from a haemodialysis-related arterio-venous shunt, from a popliteal vein aneurysm, internal jugular vein, superior vena cava, from a pulmonary arteriovenous malformation, from tricuspid valve endocarditis (with and without pulmonary embolism) and from the right atrium, respectively. Stroke was by far the commonest systemic manifestation of paradoxical embolism. Some strokes were attributable to pulmonary arteriovenous malformations with or without coexistence of intracardiac shunts. Clinicians should have a high index of suspicion for paradoxical embolism because of its time-sensitive dimension when it occurs in the context of involvement of the intracranial circulation, coronary circulation, mesenteric circulation, and peripheral limb circulation.

Genetic variants and clinical phenotypes in Korean patients with hereditary hemorrhagic telangiectasia

Objectives

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant vascular disorder characterized by recurrent epistaxis, telangiectasia, and visceral arteriovenous malformations (AVMs). Activin A receptor-like type 1 (ACVRL1/ALK1) and endoglin (ENG) are the principal genes whose mutations cause HHT. No multicenter study has yet investigated correlations between genetic variations and clinical outcomes in Korean HHT patients.

Methods

Seventy-two members from 40 families suspected to have HHT based on symptoms were genetically screened for pathogenic variants of ACVRL1 and ENG. Patients with genetically diagnosed HHT were also evaluated.

Results

In the HHT genetic screening, 42 patients from 24 of the 40 families had genetic variants that met the pathogenic criteria (pathogenic very strong, pathogenic strong, pathogenic moderate, or pathogenic supporting) based on the American College of Medical Genetics and Genomics Standards and Guidelines for either ENG or ACVRL1: 26 from 12 families (50%) for ENG, and 16 from 12 families (50%) for ACVRL1. Diagnostic screening of 42 genetically positive HHT patients based on the Curaçao criteria revealed that 24 patients (57%) were classified as having definite HHT, 17 (41%) as having probable HHT, and 1 (2%) as unlikely to have HHT. Epistaxis was the most common clinical presentation (38/42, 90%), followed by visceral AVMs (24/42, 57%) and telangiectasia (21/42, 50%). Five patients (12%) did not have a family history of HHT clinical symptoms.

Conclusion

Only approximately half of patients with ACVRL1 or ENG genetic variants could be clinically diagnosed as having definite HHT, suggesting that genetic screening is important to confirm the diagnosis.

High output cardiac failure in 3 patients with hereditary hemorrhagic telangiectasia and hepatic vascular malformations, evaluation of treatment

BACKGROUND

This report addresses how patients with hereditary hemorrhagic telangiectasia (HHT) and high output cardiac failure (HOCF) due to hepatic vascular malformations, should be evaluated and could be treated. HHT is a genetic disorder, leading to vascular abnormalities with potentially serious clinical implications. In the liver, arteriovenous malformations occur in more than 70% of patients, but only about 8% present clinical symptoms such as HOCF with pulmonary hypertension and less commonly portal hypertension, biliary ischemia and hepatic encephalopathy.

RESULTS

Three female patients with HHT type 2 and HOCF caused by severe arteriovenous malformations in the liver are presented in this case series. The patients were seen at the HHT-Centre at Odense University Hospital. Treatment with either orthotopic liver transplantation (one patient) or bevacizumab (two patients) was initiated. All patients experienced marked symptom relief and objective improvement. New York Heart Association-class were improved, ascites, peripheral edema and hence diuretic treatment was markedly reduced or discontinued in all three patients. Bevacizumab also resulted in notable effects on epistaxis and anemia.

CONCLUSION

Our findings substantiate the importance of identification of symptomatic arteriovenous malformations in the liver in patients with HHT. Bevacizumab may possibly, as suggested in this case series and supported by previous case studies, postpone the time to orthotopic liver transplantation or even make it unnecessary. Bevacizumab represents a promising new treatment option, which should be investigated further in clinical trials.

Autologous correction in patient induced pluripotent stem cell-endothelial cells to identify a novel pathogenic mutation of hereditary hemorrhagic telangiectasia

Hereditary hemorrhagic telangiectasia is a rare disease with autosomal dominant inheritance. More than 80% hereditary hemorrhagic telangiectasia patients carry heterozygous mutations of Endoglin or Activin receptor-like kinase-1 genes. Endoglin plays important roles in vasculogenesis and human vascular disease. In this report, we found a novel missense mutation (c.88T > C) of Endoglin gene in a hereditary hemorrhagic telangiectasia 1 patient. Induced pluripotent stem cells of the patient were generated and differentiated into endothelial cells. The hereditary hemorrhagic telangiectasia-induced pluripotent stem cells have reduced differentiation potential toward vascular endothelial cells and defective angiogenesis with impaired tube formation. Endoplasmic reticulum retention of the mutant Endoglin (Cys30Arg, C30R) causes less functional protein trafficking to cell surface, which contributes to the pathogenesis of hereditary hemorrhagic telangiectasia. Clustered Regularly Interspaced Short Palindromic Repeats/Cas9 genetic correction of the c.88T > C mutation in induced pluripotent stem cells revealed that C30R mutation of Endoglin affects bone morphogenetic protein 9 downstream signaling. By establishing a human induced pluripotent stem cell from hereditary hemorrhagic telangiectasia patient peripheral blood mononuclear cells and autologous correction on mutant hereditary hemorrhagic telangiectasia-induced pluripotent stem cells, we were able to identify a new disease-causing mutation, which facilitates us to understand the roles of Endoglin in vascular development and pathogenesis of related vascular diseases.

Chromosomal translocation disrupting the SMAD4 gene resulting in the combined phenotype of Juvenile polyposis syndrome and Hereditary Hemorrhagic Telangiectasia

Background

Patients with germline variants in SMAD4 can present symptoms of both juvenile polyposis syndrome (JPS) and Hereditary Hemorrhagic Telangiectasia (HHT): JP‐HHT syndrome. Next‐Generation Sequencing (NGS) techniques disclose causative sequence variants in around 90% of HHT patients fulfilling the Curaçao criteria. Here we report a translocation event involving SMAD4 resulting in JP‐HHT.

Methods

A patient fulfilling the Curaçao criteria was analyzed for variants in ENG, ACVRL1, and SMAD4 using standard techniques. Whole‐genome sequencing (WGS) using both short‐read NGS technology and long‐read Oxford Nanopore technology was performed to define the structural variant and exact breakpoints.

Results

No pathogenic variant was detected in ENG, ACVRL1, or SMAD4 in DNA extracted from blood. Due to abortus habitualis, the proband´s daughter was submitted for chromosomal analysis, and a cytogenetically balanced chromosomal reciprocal translocation t(1;18)(p36.1;q21.1) was detected in the daughter and the patient. The balanced translocation segregated with both gastrointestinal cancer and HHT in the family. WGS provided the exact breakpoints of the reciprocal translocation proving disruption of the SMAD4 gene.

Discussion

A disease‐causing reciprocal translocation between chromosome 1 and 18 with a breakpoint in the SMAD4 locus co‐segregated with JP‐HHT in an extended family. This observation warrants further analysis for chromosomal rearrangements in individuals with clinical HHT or JP‐HHT of unknown cause.

Hereditary Hemorrhagic Telangiectasia and Refractory Ascites

Hereditary hemorrhagic telangiectasia is a rare autosomal dominant disease that can involve the liver. The presence of arteriohepatic venous shunts can lead to high output cardiac failure and biliary ischemia, whereas arterioportal venous shunts can result in portal hypertension. Cirrhosis and nodular regenerative hyperplasia are also reported in these patients. Management of these patients in the setting of symptomatic liver disease is challenging. Transarterial embolization and hepatic artery ligation are usually considered palliative options. In selected cases, orthotopic liver transplantation can cure both liver disease and heart failure.

Hereditary hemorrhagic telangiectasia associated with cortical development malformation due to a start loss mutation in ENG

BACKGROUND

Hereditary hemorrhagic telangiectasia (HHT), also known as Rendu-Osler-Weber syndrome, is a rare disorder characterized by recurrent epistaxis, telangiectasias and systemic arteriovenous malformations (AVMs). HHT is associated with mutations in genes encoding for proteins involved in endothelial homeostasis such as ENG (endoglin) and ACVRL1 (activin receptor-like kinase-1).

CASE PRESENTATION

Here we describe a 22-year-old male presenting with a transient episode of slurred speech and left arm paresis. Brain MRI displayed polymicrogyria. A right-to-left shunt in absence of an atrial septum defect was noted. Chest CT revealed multiple pulmonary AVMs, likely causing paradoxical embolism manifesting as a transient ischemic attack. The heterozygous ENG variant, c.3G > A (p.Met1lle), was detected in the patient. This variant was also found in patient's mother and in his younger brother who displayed cortical dysplasia type 2.

CONCLUSIONS

The detection of cortical development malformations in multiple subjects from the same pedigree may expand the phenotypic features of ENG-related HHT patients. We suggest considering HHT in young patients presenting with acute cerebral ischemic events of unknown origin.

Impaired Release of Neutrophil Extracellular Traps and Anemia-Associated T Cell Deficiency in Hereditary Hemorrhagic Telangiectasia

Hereditary hemorrhagic telangiectasia (HHT) is characterized by mucocutaneous telangiectases and visceral vascular malformations. Individuals suffering from HHT have a significantly increased risk of bacterial infections, but the mechanisms involved in this are not clear. White blood cell subpopulations were estimated with flow cytometry in 79 patients with HHT and 45 healthy individuals, and association with clinicopathological status was assessed. A prominent decrease in absolute numbers of T cells in HHT was revealed (0.7 (0.5-1.1) vs. 1.3 (0.8-1.6), 10⁶/mL, p < 0.05), and in multivariate regression analysis, hemoglobin level was associated with lymphopenia (OR = 0.625, 95% CI: 0.417-0.937, p < 0.05). Although no changes in absolute numbers of neutrophils and monocytes were observed, we revealed a significant impairment of neutrophil antibacterial functions in HHT (n = 9), compared to healthy individuals (n = 7), in vitro. The release of neutrophil extracellular traps (NETs) against Pseudomonas aeruginosa MOI10 was significantly suppressed in HHT (mean area per cell, mm²: 76 (70-92) vs. 121 (97-128), p < 0.05), due to impaired filamentous actin organization (% of positive cells: 69 (59-77) vs. 92 (88-94), p < 0.05). To conclude, this study reveals the categories of patients with HHT that are prone to immunosuppression and require careful monitoring, and suggests a potential therapeutic strategy based on the functional activation of neutrophils.

Pulmonary arteries: imaging of pulmonary embolism and beyond

The pulmonary arteries are not just affected by thrombus. Various acquired and congenital conditions can also affect the pulmonary arteries. In this review we discuss cross sectional imaging modalities utilized for the imaging of the pulmonary arteries. Acquired pulmonary artery entities, including pulmonary artery sarcoma (PAS), vasculitis, aneurysm, and arteriovenous malformations, and congenital anomalies in adults, including proximal interruption of the pulmonary artery, pulmonary sling, pulmonary artery stenosis, and idiopathic dilatation of the pulmonary trunk, are also discussed. An awareness of these entities and their imaging findings is important for radiologists interpreting chest imaging.

Lack of Growth of Small (≤2 mm Feeding Artery) Untreated Pulmonary Arteriovenous Malformations in Patients with Hereditary Hemorrhagic Telangiectasia

PURPOSE

To assess pulmonary arteriovenous malformation (PAVM) growth among patients with untreated PAVMs using imaging from long-term follow-up per hereditary hemorrhagic telangiectasia international guidelines.

MATERIALS AND METHODS

Analysis included 88 untreated PAVMs from 21 patients (6 male;15 female; mean age at presentation 47 y; range, 12-68 y). Two CT studies with the longest interval between were evaluated (mean 8.4 y; median 8.8 y; range, 3.1-14.1 y). Measurement of feeding artery diameter and anteroposterior (AP) and mediolateral (ML) sac dimensions for each PAVM was performed separately by 2 radiologists blinded to patient and CT order. Statistical analysis was performed to determine change in size between earliest and follow-up imaging.

RESULTS

Mean feeding artery diameter, AP sac dimension, and ML sac dimension were 1.4 mm (range, 0.8-3.7 mm), 4.3 mm (range, 2.1-11.1 mm), and 4.1 mm (range, 1.8-9.2 mm) on earliest imaging and 1.4 mm (range, 0.9-2.6 mm), 4.5 mm (range, 2.2-12.2 mm), and 4.3 mm (range, 2.0-9.6 mm) on follow-up. Model-based mean analysis showed no statistically significant change in dimension of any variable between earliest and follow-up imaging. Secondary analysis including age also found no statistically significant difference (feeding diameter, P = .09; AP sac dimension, P = .9; ML sac dimension, P = .1). Analysis including time between measurements found no significant relationship between change in variables and time (feeding artery diameter, P = .4; AP sac dimension, P = .3; ML sac dimension, P = .06).

CONCLUSIONS

Untreated PAVMs grew slowly, if at all, in a near-decade span, and any demonstrated growth was minimal. These findings challenge the current recommendation of 3- to 5-year CT follow-up.

Comorbidity among HHT patients and their controls in a 20 years follow-up period

Background

Hereditary Haemorrhagic Telangiectasia (HHT) is an autosomal dominant genetic disorder with a wide variety of clinical manifestations due to the presence of multiple arteriovenous malformations in various tissues and organs.

Objective

To study the need for hospital admittance in a group of HHT patients and matched controls during a 20 years follow-up period commencing in 1995.

Methods

All HHT patients in the County of Funen, Denmark, were included. For each patient, three age and sex matched controls were identified at the time of enrolment. Data on all hospitalisations were extracted from the national health registers and compared with clinical records. The hospitalisations were grouped as HHT relevant or not HHT relevant based on the discharge diagnosis (International Classification of Diseases, ICD10) and with particular focus on infections, bleedings and thromboembolic events.

Patients with HHT were compared with controls concerning the first time incidence of each discharge diagnosis.

Results

We included 73 HHT patients and 219 controls of which one control was lost to follow-up. HHT-patients had significantly more hospitalisations per person caused by infections in joints and bones, but not caused by infections in general. Bleeding episodes were, as expected, more frequent among the HHT-patients. The study revealed a similar incidence of abscesses and thromboembolisms, including in the central nervous system, among the HHT patients and controls.

Conclusions

Based on this study Danish HHT patients had an increased comorbidity of infections in joints and bones and of bleeding episodes. However, the incidence of thromboembolisms, cerebral abscesses and other conditions commonly considered related to HHT was comparable between the patients and the controls. The patients included in this study were closely monitored at a highly specialised HHT Centre where they received relevant diagnostic evaluation, treatment and counselling. Since this is assumed to benefit the overall health of the patients, it may explain why these patients were less prone to comorbidity than other studies have suggested.

Electronic supplementary material

The online version of this article (10.1186/s13023-018-0962-8) contains supplementary material, which is available to authorized users.

Links Between Strokes and Hereditary Hemorrhagic Telangiectasia: A Population-Based Study

BACKGROUND

Hereditary hemorrhagic telangiectasia (HHT) is a disease of abnormal vasculature where patients are predisposed to strokes of multiple etiologies. We assessed yearly stroke incidence among Albertans with HHT and compared with the general population. Given the tendency for stroke in HHT patients, we expected HHT patients to have higher stroke incidence, in particular at younger ages.

METHODS

Population-based administrative health data on inpatient and ambulatory admissions were extracted over a 16-year period using International Classification of Diseases (ICD)-9 and ICD-10, Canada codes. We analyzed overall occurrence of strokes in Alberta by age, gender, stroke subtype, and diagnosis of HHT.

RESULTS

The age-standardized incidence rate of stroke in HHT was 450 per 100,000 compared with 260 per 100,000 in the general population with a rate ratio of 1.73 (95% confidence interval (CI) [1.046-2.842]). This study found a higher HHT prevalence in Alberta (1 in 3800) compared to the world average of 1 in 5000. Women were also more likely to be diagnosed with HHT, with a 3.25:1 female gender preponderance in the yearly incidence.InterpretationThis study not only shows that HHT patients are at higher risk of having a stroke but also quantifies that risk using an age-adjusted metric in Alberta. This province has a higher than expected disease burden of HHT, with the majority of cases affecting women. Our study found that acute ischemic strokes and transient ischemic attacks are far more common than hemorrhage in HHT. As HHT is a rare, multi-system, chronic disease, these patients should be referred to an HHT Centre of Excellence.

Preliminary experience with the micro vascular plug for the treatment of pulmonary arteriovenous malformation: case series of four patients

Background

To describe the preliminary experience using Micro Vascular Plug (MVP) for treatment of pulmonary arteriovenous malformations (PAVMs) with small feeding arteries (3 -5 mm) in four patients with Hereditary Haemorrhagic Telangiectasia (HHT).

Material and methods

One female and three male patients with PAVMs have been treated during 2017. The mean age was 32.5 years; (range: 20-53). All patients underwent contrast echocardiography and computed tomography of the chest to establish the diagnosis.

Results

Four patients with PAVMs were treated with embolisation using the MVP-3Q and MVP-5Q micro plugs. All MVP were placed without complications and with following immediate occlusion of the PAVMs in all three cases. In one case MVP was placed semi selectively. All cases were with the good clinical outcomes.

Conclusion

MVP is a new detachable embolisation material which is easy to use. Maximal control during the deployment and immediate occlusion of the target vessels can be achieved.

Embolisation of pulmonary arteriovenous malformations - case series

Purpose

Pulmonary arteriovenous malformations (PAVM) are the direct communications between the pulmonary arteries and veins. These malformations can cause serious complications, and most of these patients should be treated. Herein we present our experience in the treatment of 18 cases of PAVM, treated with endovascular embolisation.

Material and methods

Eighteen patients with PAVMs underwent endovascular embolisation during a five-year period. Eight were male and 10 were female, with ages ranging from 16 to 65 years. Standard steel coils and vascular plug were used for embolisation.

Results

Embolisation was successful in 17 of 18 patients. Coiling was used in 10 patients, vascular plug in five, and both materials in two patients. All symptomatic patients with successful embolisation lost all their symptoms after treatment. Control angiography after embolisation showed a closure of AV shunt without migration of embolic material in all patients. Post-embolisation syndrome developed in four patients and late onset of pleural pain in three patients. There was no connection between pleural reaction and type of PAVM and embolic material.

Conclusions

Endovascular PAVM treatment is a minimally invasive, highly successful method with a low rate of only transitory complications.

ENG mutational mosaicism in a family with hereditary hemorrhagic telangiectasia

Background

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant genetic disorder caused by mutations in ENG,ACVRL1, or SMAD4. Around 90% of HHT patients present with a heterozygous pathogenic genetic variation. Almost all cases of HHT have a family history. Very few cases are de novo or mosaicism. We describe a case with mutational mosaicism that would not be observed in the clinical routine when using Sanger sequencing or a NGS read coverage below app. 100.

Methods

DNA was extracted from peripheral blood leukocytes, and buccal swabs. The coding region, exon–intron boundaries, and the flanking sequences of the genes were sequenced by NGS.

Results

The proband had clinical HHT fulfilling the Curaçao criteria and genetic testing identified a frameshift mutation in ENG. The mother of the proband, also with clinical HHT, was found negative when analyzing DNA from blood for the familial mutation using Sanger sequencing. Analyzing her DNA by NGS HHT panel sequencing when extracted from both peripheral blood leukocytes, and cheek swabs, identified the familial ENG mutation at low levels.

Conclusion

We provide evidence of ENG mutational mosaicism in an individual presenting with clinical HHT. These findings illustrate the importance of considering mutational mosaicism.

Familial cerebral abscesses caused by hereditary hemorrhagic telangiectasia

In case of a cerebral abscess without known cause, Pulmonary arteriovenous malformations (PAVM) screening should be performed. If PAVM(s) is identified, Hereditary hemorrhagic telangiectasia (HHT) is very likely and should always be considered. This case shows the benefit of familial screening for HHT and PAVM.

Effect of pulmonary arteriovenous malformations on the mechanical properties of the lungs

BACKGROUND

Pulmonary arteriovenous malformations (PAVMs) are present in approximately 15-50% individuals with hereditary hemorrhagic telangiectasia (HHT). They may be isolated but more often are multiple. The goal of this study was to evaluate the influence of PAVMs on lung mechanical properties.

METHODS

We reviewed the files of all adult patients (age ≥ 18 years) referred to our Center for evaluation of HHT between 2005 and 2013. The diagnosis of HHT was based on the Curacao criteria and/or the presence of a pathogenic mutation. Exclusion criteria included: chronic cardiac or lung disease (i.e. asthma or COPD), suspicion of pulmonary hypertension on echocardiography, current or past smoking (>10 pack-years), history of thoracic surgery, previous treatment of PAVMs by embolotherapy, lung infection or thromboembolic disease in the past 3 months, pregnancy and obesity (BMI > 30 kg/m²). Chest high resolution CT-scan and pulmonary function tests were performed the same day in all patients as part of our routine work-up.

RESULTS

One hundred and fifty five patients with HHT were included (age: 44.4 ± 16.7 yrs - mean ± SD -; males: 39%). Eighty eight patients had no PAVM, 45 had 1-3 PAVMS and 22 had at least 4 PAVMs. Thirty eight patients had unilateral PAVMs and 29 bilateral PAVMs. We found no statistical relationship between the number, the size and the laterality of PAVMs and results of lung flows and volumes.

CONCLUSION

We found no evidence that PAVMs have a significant influence on lung mechanical properties as measured using routine pulmonary function tests in adult patients with HHT, even in case of numerous, macroscopic or bilateral malformations.

20-year follow-up study of Danish HHT patients-survival and causes of death

Background

Hereditary Haemorrhagic Telangiectasia (HHT) is a dominantly inheritable disorder, with a wide variety of clinical manifestations due to presence of multiple arteriovenous manifestations. The most common mutations are found in HHT1 (ENG) and HHT2 (ACVRL1) patients, causing alterations in the TGF-β pathway which is responsible for angiogenesis. Modulations of angiogenesis may influence cancer rates. The objective of the study was to evaluate 20-year survival according to HHT subtype, as well as to evaluate differences in causes of death comparing HHT patients and controls. We also wanted to investigate whether cancer morbidity among HHT patients differs from that among controls.

Results

We included all HHT patients in the County of Fyn, Denmark, prevalent as of January 1st 1995 in total 73 HHT patients. In addition three age- and sex- matched controls per HHT patient were evaluated, in total 218 controls (one was lost due to registration failure). The controls were defined at start of follow-up in 1995. Information on lifestyle factors was not available. A total of 32 (44%) HHT patients and 97 (44%) controls passed away during follow-up. The survival curves were evenly distributed showing similar survival rates in the two groups. Cancer diagnoses had been registered in the follow-up period in 4 (5%) HHT patients and in 38 (17%) controls.

Conclusion

The mortality was not increased among Danish HHT patients compared to controls. This study is based on a clinical unselected series of HHT patients with the whole spectrum of severity, independent of need for medical care. Our data also suggest that HHT patients to a lesser degree than the background population are affected by cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/s13023-016-0533-9) contains supplementary material, which is available to authorized users.

Executive summary of the 11th HHT international scientific conference

Hereditary hemorrhagic telangiectasia (HHT) is a hereditary condition that results in vascular malformations throughout the body, which have a proclivity to rupture and bleed. HHT has a worldwide incidence of about 1:5000 and approximately 80 % of cases are due to mutations in ENG, ALK1 (aka activin receptor-like kinase 1 or ACVRL1) and SMAD4. Over 200 international clinicians and scientists met at Captiva Island, Florida from June 11-June 14, 2015 to present and discuss the latest research on HHT. 156 abstracts were accepted to the meeting and 60 were selected for oral presentations. The first two sections of this article present summaries of the basic science and clinical talks. Here we have summarized talks covering key themes, focusing on areas of agreement, disagreement, and unanswered questions. The final four sections summarize discussions in the Workshops, which were theme-based topical discussions led by two moderators. We hope this overview will educate as well as inspire those within the field and from outside, who have an interest in the science and treatment of HHT.

Screening for arteriovenous malformations in hereditary haemorrhagic telangiectasia

OBJECTIVE

To determine whether patients with hereditary haemorrhagic telangiectasia were being screened according to international guidelines, and to review recent evidence in order to provide up-to-date guidelines for the initial systemic management of hereditary haemorrhagic telangiectasia.

METHODS

A retrospective case note analysis was conducted, assessing patients in terms of screening for: genetics, cerebral arteriovenous malformations, pulmonary and hepatic arteriovenous malformations, and gastrointestinal telangiectasia. Databases searched included Medline, the Cumulative Index to Nursing and Allied Health Literature, and Embase.

RESULTS

Screening investigations were most frequently performed for hepatic arteriovenous malformations and least frequently for genetics. Recent data suggest avoiding routine genetic and cerebral arteriovenous malformation screening because of treatment morbidities; performing high-resolution chest computed tomography for pulmonary arteriovenous malformation screening; using capsule endoscopy (if possible) to reduce complications from upper gastrointestinal endoscopy; and omitting routine liver enzyme testing in favour of Doppler ultrasound.

CONCLUSION

Opportunities for systemic arteriovenous malformation screening are frequently overlooked. This review highlights the need for screening and considers the form in which it should be undertaken.

Global gene expression profiling of telangiectasial tissue from patients with hereditary hemorrhagic telangiectasia

Hereditary hemorrhagic telangiectasia (HHT), the most common inherited vascular disorder, is predominantly caused by mutations in ENG and ACVRL1, which are part of the transforming growth factor beta (TGF-β) signaling pathway. HHT is characterized by the presence of mucocutaneous telangiectases and arteriovenous malformations in visceral organs, primarily the lungs, brain and liver. The most common symptom in HHT is epistaxis originating from nasal telangiectasia, which can be difficult to prevent and can lead to severe anemia. The clinical manifestations of HHT are extremely variable, even within family members, and the exact mechanism of how endoglin and ALK1 haploinsufficiency leads to HHT manifestations remains to be identified.

OBJECTIVES

The purpose of this study was to detect significantly differentially regulated genes in HHT, and try to elucidate the pathways and regulatory mechanisms occurring in the affected tissue of HHT patients, in order to further characterize this disorder and hypothesize on how telangiectases develop. By microarray technology (Agilent G3 Human GE 8x60), we performed global gene expression profiling of mRNA transcripts from HHT nasal telangiectasial (n = 40) and non-telangiectasial (n = 40) tissue using a paired design. Comparing HHT telangiectasial and non-telangiectasial tissue, significantly differentially expressed genes were detected using a paired t-test. Gene set analysis was performed using GSA-SNP. In the group of ENG mutation carriers, we detected 67 differentially expressed mRNAs, of which 62 were down-regulated in the telangiectasial tissue. Gene set analysis identified the gene ontology (GO) terms vasculogenesis, TGF-β signaling, and Wnt signaling as differentially expressed in HHT1. Altered Wnt signaling might be related to HHT pathogenesis and a greater understanding of this may lead to the discovery of therapeutic targets in HHT.

Complications and mortality in hereditary hemorrhagic telangiectasia: A population-based study

OBJECTIVES

Studies report that the risks of significant neurologic complications (including stroke, cerebral abscess, and migraine) and hemorrhagic sequelae are high in patients with hereditary hemorrhagic telangiectasia (HHT), and that life expectancy in this cohort is reduced. However, most published cohorts derive from specialist centers, which may be susceptible to bias.

METHODS

We used a population-based approach to estimate the risks of developing neurologic and hemorrhagic complications of HHT, the association of a diagnosis of HHT with common cardiovascular and malignant comorbidities, and also long-term survival of those with the disease.

RESULTS

From a UK primary care database of 3.5 million patients (The Health Improvement Network), we identified 675 cases with a diagnosis of HHT and compared them with 6,696 controls matched by age, sex, and primary care practice. Risks of stroke (odds ratio [OR] 1.8, 95% confidence interval [CI] 1.2-2.6), cerebral abscess (OR 30.0, CI 3.1-288), and migraine (OR 1.7, CI 1.3-2.2) were elevated over controls. Bleeding complications including epistaxis (OR 11.6, CI 9.1-14.7) and gastrointestinal hemorrhage (OR 6.1, CI 2.8-13.4) were more common in cases with HHT. Survival of cases with HHT was poorer than controls with a hazard ratio for death of 2.0 (CI 1.6-2.6) and a median age at death 3 years younger.

CONCLUSIONS

Patients with HHT are at substantially increased risk of serious neurologic and hemorrhagic complications of the disease. Because a diagnosis of HHT is associated with a significantly poorer survival compared with those who have no disease, evaluation of new strategies to improve clinical management is required.

Clinical implications of pulmonary shunting on saline contrast echocardiography

Pulmonary right-to-left shunting can be encountered using transthoracic contrast echocardiography (TTCE) with agitated saline. Diseases associated with pulmonary shunting on saline TTCE include hereditary hemorrhagic telangiectasia (HHT), hepatopulmonary syndrome, and some congenital heart defects after partial or complete cavopulmonary anastomosis. Furthermore, small pulmonary shunts on saline TTCE are also documented in a proportion of healthy individuals. Pulmonary shunting carries the risk for severe neurologic complications due to paradoxical embolization. In HHT, additional chest computed tomography is recommended in case of any pulmonary shunt detected on saline TTCE, to evaluate the feasibility for transcatheter embolotherapy of pulmonary arteriovenous malformations. Furthermore, antibiotic prophylaxis is advised in case of any pulmonary shunt on saline TTCE to prevent brain abscesses after procedures with risk for bacteremia. The present review provides an overview of important aspects of pulmonary shunting and its detection using saline TTCE. Furthermore, advances in understanding the clinical implications of different pulmonary shunt grades on saline TTCE are described. It appears that small pulmonary shunts on saline TTCE (grade 1) lack any clinical implication, as these shunts cannot be used as a diagnostic criterion for HHT, are not associated with an increased risk for neurologic complications, and represent pulmonary arteriovenous malformations too small for subsequent endovascular treatment. This implies that additional chest computed tomography could be safely withheld in all persons with only small pulmonary shunts on saline TTCE and sets the stage for further discussion about the need for antibiotic prophylaxis in these subjects. Besides further optimization of the current screening algorithm for the detection of pulmonary arteriovenous malformations in HHT, these observations can be of additional clinical importance in other diseases associated with pulmonary shunting and in those healthy individuals with documented small pulmonary shunts on saline TTCE.

Clinical characteristics of pulmonary arteriovenous malformations in Koreans

BACKGROUND AND OBJECTIVE

Although pulmonary arteriovenous malformations (PAVMs) are rare, they are important in clinical practice because they are associated with life-threatening complications such as brain abscess, stroke and lung haemorrhage. The aims of the present study were to characterize PAVMs in a Korean population and to examine the incidence and factors associated with cerebral complications, which are a major cause of mortality.

METHODS

The medical records of patients with PAVMs between 2000 and 2013 were retrospectively reviewed. PAVMs were confirmed by enhanced chest computed tomography or by pulmonary angiography.

RESULTS

Ninety patients (median age, 47.5 years; 81.8% female) with PAVMs were included. Twelve patients (13.3%) were clinically diagnosed with hereditary haemorrhagic telangiectasia (HHT) according to the Curacao criteria. Sixty-three patients underwent transcatheter embolization with no severe adverse events. Three patients required retreatment during a mean follow-up period of 3.3 years. Six and 14 patients suffered brain abscess or stroke, respectively, as a complication of PAVMs. These complications were not associated with the diameter of the arteries feeding the PAVMs (odds ratio, 1.106; 95% confidence interval, 0.895-1.366; P = 0.352) CONCLUSIONS: PAVMs are less associated with HHT in Koreans than in Western populations. Transcatheter embolization of PAVMs is safe and effective, and physicians need to consider treating the small arteries feeding PAVMs to prevent cerebral complications.

Long non-coding RNA expression profiles in hereditary haemorrhagic telangiectasia

Hereditary Haemorrhagic Telangiectasia (HHT) is an autosomal dominantly inherited vascular disease characterized by the presence of mucocutaneous telangiectasia and arteriovenous malformations in visceral organs. HHT is predominantly caused by mutations in ENG and ACVRL1, which both belong to the TGF-β signalling pathway. The exact mechanism of how haploinsufficiency of ENG and ACVRL1 leads to HHT manifestations remains to be identified. As long non-coding RNAs (lncRNAs) are increasingly recognized as key regulators of gene expression and constitute a sizable fraction of the human transcriptome, we wanted to assess whether lncRNAs play a role in the molecular pathogenesis of HHT manifestations. By microarray technology, we profiled lncRNA transcripts from HHT nasal telangiectasial and non-telangiectasial tissue using a paired design. The microarray probes were annotated using the GENCODE v.16 dataset, identifying 4,810 probes mapping to 2,811 lncRNAs. Comparing HHT telangiectasial tissue with HHT non-telangiectasial tissue, we identified 42 lncRNAs that are differentially expressed (q<0.001). Using GREAT, a tool that assumes cis-regulation, we showed that differently expressed lncRNAs are enriched for genomic loci involved in key pathways concerning HHT. Our study identified lncRNAs that are aberrantly expressed in HHT telangiectasia and indicates that lncRNAs may contribute to regulate protein-coding loci in HHT. These results suggest that the lncRNA component of the transcriptome deserves more attention in HHT. A deeper understanding of lncRNAs and their role in telangiectasia formation possesses potential for discovering therapeutic targets in HHT.

Cerebral abscesses among Danish patients with hereditary haemorrhagic telangiectasia

BACKGROUND

Hereditary haemorrhagic telangiectasia (HHT) is a dominantly inherited disease characterized by a wide variety of clinical manifestations, including pulmonary arteriovenous malformations (PAVMs), which due to paradoxical embolization may cause cerebral abscess.

OBJECTIVE

To estimate the risk of cerebral abscess among patients with HHT.

METHODS

All patients with HHT included in the Danish HHT data base, between January 1995 and October 2012, have been clinically evaluated for the presence of neurological symptoms and history of previous cerebral abscess.

RESULTS

A total of 337 patients with HHT have been included in the Danish database. Of these, 264 were screened for the presence of PAVM. In 117 patients, a PAVM was diagnosed; among these, we identified nine patients with a history of cerebral abscess. The prevalence of cerebral abscess among patients with HHT and PAVM was therefore 7.8%. The patients with a history of cerebral abscess were genetically evaluated, and seven had ENG mutations, one had an ALK1 mutation, and in one case, a mutation could not be identified.

CONCLUSION

Patients with untreated PAVM have a considerable risk of sustaining cerebral abscesses. A cerebral abscess may be the first symptom leading to an HHT diagnosis. Patients with unexplained cerebral abscess should be evaluated for HHT and PAVM.

Grade of pulmonary right-to-left shunt on contrast echocardiography and cerebral complications: a striking association

BACKGROUND

A pulmonary right-to-left shunt (RLS) carries the risk of cerebral paradoxical embolization and severe neurologic complications. Recognizing patients at risk is important to facilitate appropriate management strategies, but a direct relation between pulmonary shunt size and risk of complications remains controversial. This study evaluated the potential relation between pulmonary shunt grade on transthoracic contrast echocardiography (TTCE) and prevalence of cerebral manifestations in patients screened for hereditary hemorrhagic telangiectasia (HHT).

METHODS

We conducted a two-center, cross-sectional study of all consecutive patients screened for HHT between 2004 and 2011. Pulmonary shunt grading on TTCE (grade 0, no microbubbles; grade 1, &lt; 30 microbubbles; grade 2, 30-100 microbubbles; grade 3, &gt; 100 microbubbles) was performed according to contrast opacification of the left ventricle. Cerebral complications were defined as ischemic stroke, transient ischemic attack, or brain abscess diagnosed by a neurologist and confirmed by appropriate imaging techniques.

RESULTS

A pulmonary RLS was present in 530 out of 1,038 patients (51.1%; mean age, 44.3 ± 15.6 years; 58.6% women). The presence of a cerebral manifestation (n = 51) differed significantly among pulmonary shunt grades on TTCE: 1.4%, 0.4%, 6.5%, and 20.9% for grades 0, 1, 2 and 3, respectively. A pulmonary shunt grade 1 was not associated with an increased prevalence of cerebral manifestations (OR, 0.44; 95% CI, 0.05-4.13; P = .47), whereas pulmonary shunt grade 2 (OR, 4.78; 95% CI, 1.14-20.0; P = .03) and grade 3 (OR, 10.4; 95% CI, 2.4-45.3; P = .002) were both independent predictors for the prevalence of a cerebral ischemic event or brain abscess.

CONCLUSIONS

The pulmonary RLS grade on TTCE is strongly associated with the prevalence of cerebral complications in patients screened for HHT.

Angina pectoris or myocardial infarctions, pulmonary arteriovenous malformations, hereditary hemorrhagic telangiectasia, and paradoxical emboli

Hereditary hemorrhagic telangiectasia is an autosomal dominant disorder characterized by vascular malformations, and many clinical complications are related to pulmonary arteriovenous malformations (PAVMs) because they provide direct right-to-left shunts. Paradoxical emboli through these shunts are a well-recognized cause of transient ischemic attack, stroke, and cerebral abscess. The aim of this study was to determine whether paradoxical emboli through PAVMs could manifest as cardiac ischemic events. The study included a single-center population of 98 patients with PAVMs. Eighty-four had undergone PAVM embolotherapy, and the remaining 14 patients had PAVMs too small to require embolization. Patients were interviewed by telephone and surveyed regarding their cardiopulmonary symptoms and histories of cardiac diagnoses. We found that 6 patients (which is 18% of patients with symptomatic PAVMs, n = 33, and 6% of the total cohort, n = 98) reported that they had experienced typical angina pectoris-like chest pain or had a myocardial infarction before PAVM embolotherapy. Five patients had had a cardiac catheterization, 4 had normal coronary arteries, and 1 had a single artery occlusion. In conclusion, we suggest that in patients with untreated PAVMs, cardiac ischemia can occur because of a paradoxical embolus through PAVMs to a coronary artery.

Fatal Systemic Embolism following Revision of Hip Arthroplasty: A Complication of Pulmonary Arteriovenous Malformation

A 72-year-old female patient who had a pulmonary arteriovenous malformation (PAVM) suffered systemic emboli causing pulmonary and cerebral infarction following the revision of an infected total hip replacement. Although not ultimately successful in this case, we detail the management of maintaining oxygenation and adequate cardiac output in a critically ill patient with a PAVM. We also discuss techniques that may be employed to minimise the shunt associated with the PAVM, with the aim of reducing the risk of systemic emboli.

Juvenile polyposis, hereditary hemorrhagic telangiectasia, and early onset colorectal cancer in patients with SMAD4 mutation

BACKGROUND

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant disorder most often caused by mutation in the endoglin or ALK1 genes. A distinct syndrome combines the clinical features of HHT and juvenile polyposis (JP) and has been associated with SMAD4 mutation. The aim of this study was to describe the phenotype of patients with JP-HHT and SMAD4 mutations and to compare this phenotype with HHT or JP patients with mutations other than SMAD4.

METHODS

Patients prospectively enrolled in the Toronto HHT and JP databases who underwent genotyping were included. The phenotypic characteristics of JP-HHT patients with SMAD4 mutations and patients with mutations other than SMAD4 were analyzed and compared.

RESULTS

Three hundred and fifty-eight patients underwent genetic testing (HHT, n = 332; JP, n = 26). Among fourteen patients identified with SMAD4 mutations, ten met the clinical diagnostic criteria for both JP and HHT (71%). Patients with SMAD4 mutations had 100% penetrance of the polyposis phenotype. All patients with JP and SMAD4 mutation had features of HHT. Three JP-HHT patients developed early onset colorectal cancer (CRC) (mean age 28 years). JP-HHT patients with SMAD4 mutation had a significantly higher rate of anemia than HHT patients with mutations other than SMAD4.

CONCLUSIONS

Patients with HHT and SMAD4 mutations are at significant risk of JP and CRC. The gastrointestinal phenotype is similar to JP patients without SMAD4 mutation. It is essential for HHT patients to undergo genetic testing to determine if they have SMAD4 mutations so that appropriate gastrointestinal screening and surveillance for JP and CRC can be completed.

Embolization of pulmonary AVMs of feeding arteries less than 3 mm: reports of two cases and an 8-year follow-up without embolization

Pulmonary arteriovenous malformations (PAVMs) with feeding arteries of 3 mm or more have been shown to be associated with paradoxical embolization and serious neurologic complications. Therefore it is generally recommended to occlude feeding arteries of this size, while smaller feeding arteries often are left untreated. However, neurologic complications have also been described in patients with small PAVMs, and it has not been possible to stratify risk by size of feeding artery and thus there is no evidence that 3 mm is the critical size of the feeding artery potentially giving complications. Further, it is well-known that with time PAVMs and their feeding arteries may enlarge. Also, embolization of small feeding arteries will minimize the risk of paradoxical emboli and reduce the need for CT follow-up controls in these patients. Two cases demonstrate the possibility to embolize small feeding arteries.