Screening For Pulmonary Arteriovenous Malformations Research Articles

MRI as screening for pulmonary arteriovenous malformations in hereditary hemorrhagic telangiectasia.

A four-year-old boy was newly diagnosed with Hereditary Haemorrhagic Telangiectasia (HHT) based on cascade genetic testing This article is protected by copyright. All rights reserved.

Evolution of Pulmonary Arteriovenous Malformations: The Role of Contrast Echocardiography

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

Cyanosis in a Previously Well Child.

Cyanosis in a Previously Well Child.

Approach to Pulmonary Arteriovenous Malformations: A Comprehensive Update.

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

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

High-resolution chest CT (HRCT) scan is recommended after pulmonary arteriovenous malformation (PAVM) embolotherapy to assess for PAVM persistence and untreated PAVM growth. Graded transthoracic contrast echocardiography (TTCE) predicts the need for embolotherapy in PAVM screening. This study sought to determine whether postembolotherapy graded TTCE can similarly predict the need for repeat embolotherapy. Thirty-two patients (8 men and 24 women; mean age, 51.1 ± 12.6 years) with prior PAVM embolotherapy and follow-up HRCT scan were prospectively enrolled. Patients underwent graded TTCE using a validated three-point quantitative grading scale. TTCE grade and HRCT findings were compared. Median time between most recent HRCT scan and TTCE was 7days (interquartile range, 0-272days). Thirty patients (94%) had no PAVMs requiring repeat embolotherapy on HRCT scan. Two patients (6%) had PAVMs requiring repeat embolotherapy (feeding artery [FA]≥ 3mm), one with untreated PAVM growth and one with treated PAVM persistence. TTCE was positive in 88%of patients (n= 28). All patients (n= 4, 12%) with negative TTCE had no visible PAVMs on HRCT scan. Nine patients (32%) had grade 1 shunt, 10 (35%) had grade 2 shunt, and nine (32%) had grade 3 shunt. No patients with grade 1 shunt had PAVMs amenable to repeat embolotherapy on HRCT scan. All patients (n= 2) with PAVMs requiring repeat embolotherapy (FA≥ 3mm) had grade 3 shunt. TTCE grade was significantly associated with PAVM FA diameter (P< .001). Postembolotherapy graded TTCE can predict the need for repeat embolotherapy on HRCT scan. Patients with negative TTCE and grade 1 shunt may not require HRCT follow-up and can potentially be followed with serial graded TTCE. ClinicalTrials.gov; No.: NCT02936349; URL: www.clinicaltrials.gov.

Diagnostic Yield of Rescreening Adults for Pulmonary Arteriovenous Malformations.

To determine the yield of rescreening adult hereditary hemorrhagic telangiectasia (HHT) patients with initial negative screening CT for pulmonary arteriovenous malformations (PAVMs). Patients with a definite diagnosis of HHT were identified in the University of Toronto, Université de Montréal, and Mayo Clinic HHT databases. Inclusion criteria were: (i) definite diagnosis of HHT; (ii) initial negative PAVM screening based on bubble echocardiography and/or chest CT; and (iii) minimum 2-year imaging follow-up. A positive rescreen was defined as a newly detected PAVM on follow-up CT. Frequency of new PAVMs was calculated at 3 ± 1 years, 5 ± 1 years, 7-9 years, and ≥10 years. The primary endpoint was the rate of new PAVMs at 5 ± 1 years. One hundred seventy-two patients (mean age, 49.6 ± 16.7 years; 59% female) were followed for a median of 7 years. Nine patients (5.2%) had newly detected PAVMs. At the 3-, 5-, 7-, and ≥10-year time points, the cumulative rate of newly detected PAVMs was 1.8% (3/166), 5.0% (7/140), 8.8% (8/91), and 13.8% (9/65), respectively. Median feeding artery diameter was 1.3 mm. One patient had a feeding artery larger than 3 mm discovered after 6 years and was treated with embolization. The overall rate of newly detected PAVMs was 0.7%/patient-year. There is a definite but low rate of newly detected PAVMs in HHT patients with initial negative screening studies. No new treatable PAVMs were identified at the 5-year mark, although 1 treatable case was identified after 6 years. These findings suggest that a longer screening interval may be warranted.

European Reference Network For Rare Vascular Diseases (VASCERN) Outcome Measures For Hereditary Haemorrhagic Telangiectasia (HHT)

Hereditary haemorrhagic telangiectasia (HHT) is a multisystemic vascular dysplasia that leads to nosebleeds, anaemia due to blood loss, and arteriovenous malformations (AVMs) in organs such as the lungs, liver and brain. HHT is estimated to affect 85,000 European citizens, but most health care providers have limited prior HHT exposure or training.Outcome Measures were developed and implemented by the HHT Working Group of the European Reference Network for Rare Vascular Diseases (VASCERN), in order to maximise the number of patients receiving good care. The measures specifically target areas where optimal management reduces morbidity and mortality in HHT patients, and were designed to be robust to emerging new evidence. Thresholds are the percentage of patients in particular settings who have been recommended screening, or provided with written advice. The 5 Outcome Measures cover (1) pulmonary AVM screening; (2) written nosebleed advice, (3) assessment of iron deficiency; (4) antibiotic prophylaxis prior to dental and surgical procedures for patients with pulmonary AVMs, and (5) written advice on pregnancy. They are not a blueprint for detailed HHT management, but are suitable for all clinicians to be aware of and implement.In summary, these 5 Outcome Measures provide metrics to identify healthcare providers of good care, and encourage care improvement by all healthcare providers.

Mutations in the ENG, ACVRL1, and SMAD4 genes and clinical manifestations of hereditary haemorrhagic telangiectasia: experience from the Center for Osler’s Disease, Uppsala University Hospital

Aim: The aim of this retrospective single-centre study was to evaluate whether mutations in the ENG, ACVRL1, and SMAD4 genes were associated with different phenotypes in hereditary haemorrhagic telangiectasia (HHT).Methods: The case records of 21 HHT patients with verified mutations in ENG, ACVRL1, or SMAD4 genes were reviewed. The numbers of HHT diagnostic criteria fulfilled for the three genotypes were compared, as was the prevalence of complications such as iron deficiency anaemia, gastrointestinal haemorrhage, stroke, and cerebral abscess.Results: Our results indicate that mutations in the ENG (HHT1), ACVRL1 (HHT2), and SMAD4 genes result in different HHT phenotypes. Epistaxis debuts earlier and may be more severe in HHT1 than in HHT2. The prevalence of pulmonary arteriovenous malformations (AVM) is higher in HHT type 1, whereas hepatic AVMs are more common in HHT2. One patient with mutations in both ENG and ACVRL1 genes was identified, as were two SMAD4-mutated patients suffering from the overlapping juvenile polyposis-HHT syndrome. Nearly one in five patients in our HHT population has been diagnosed with stroke or cerebral abscess, indicating a high prevalence of cerebral complications.Conclusion: Our results showing that ENG and ACVRL1 gene mutations result in different HHT phenotypes confirm the results from other HHT centres worldwide. Cerebral complications of HHT are common, underscoring the importance of regular screening for pulmonary AVMs and early intervention against such AVMs. We have identified an HHT patient with simultaneous mutations in the ENG and ACVRL1 genes. Surprisingly, this patient has had a mild course of the disease.

Pulmonary Arteriovenous Malformations: A Rare Cause of Recurrent Stroke

SESSION TITLE: Lung Pathology 2 SESSION TYPE: Affiliate Case Report Poster PRESENTED ON: Tuesday, October 31, 2017 at 01:30 PM - 02:30 PM INTRODUCTION: Pulmonary arteriovenous malformations (PAVMs) are exceedingly rare, with an estimated prevalence of 38/10,000.1 Like intra-cardiac shunts, PAVMs can lead to paradoxical emboli and stroke, and their detection and management is therefore critical.2 We present a case of recurrent stroke secondary to a large AVM, discovered via saline-contrast echocardiography (SCE), with particular attention to bubble transit time. CASE PRESENTATION: A 77 year old female presented to the Emergency Room with dysarthria, right-sided weakness, and gait imbalance. MRI/MRA brain revealed sub-acute infarcts in the left pons, left superior cerebral peduncle, and right posterior cerebellum. Intra-cranial and intra-cervical arteries were patent. Telemetry monitoring did not reveal atrial fibrillation, and prior Holter monitoring did not reveal significant arrhythmia. Transthoracic echocardiogram (TTE) did not reveal any shunt. Aspirin was switched to clopidogrel and high-intensity statin was added. Two months later, she developed acute left-sided weakness. MRI brain revealed an acute infarct in the posterior right parietal lobe. SCE was positive for right to left shunt with delayed transit time. Chest X-ray showed an irregular opacity within the right middle lobe (RML). This appeared to be in the same location as a previously known PAVM on comparison to old imaging done 6 years prior. CT chest then revealed an enlarging PAVM in the RML, now with a diameter of >6 mm. She subsequently underwent coil embolization and is doing well. DISCUSSION: In a normal individual, peripherally injected saline bubbles are not observed in the left heart as lung capillaries act as filters.2 Their presence therefore indicates a right-to-left shunt, and transit time can help differentiate between intra-cardiac and intra-pulmonary shunts, both of which can lead to recurrent stroke.3 Delayed transit time of >6 beats is highly suggestive of intra-pulmonary shunting.3 Our case illustrates the need to differentiate between these two shunts, as PAVMs are indeed a rare cause of recurrent stroke. CONCLUSIONS: Though there is currently no role for PAVM screening in the work-up of stroke, routine SCE should be done for intra-cardiac shunt evaluation. As SCE also has a sensitivity of around 1.00 in the detection of PAVMs, one can therefore pick up more rare etiologies of stroke using this modality.3 Reference #1: Nakayama M, Nawa T, Chonan T, et al. Prevalence of pulmonary arteriovenous malformations as estimated by low-dose thoracic CT screening. Internal Medicine. 2012; 51(13): 1677-1681. Reference #2: Attaran, RR, Ata I, Kudithipudi V, et al. Protocol for optimal detection and exclusion of a patent foramen ovale using transthoracic echocardiography with agitated saline microbubbles. Echocardiography. 2006; 23(7): 616-622. Reference #3: Gazzaniga P, Buscarini E, Leandro G, et al. Contrast echocardiography for pulmonary arteriovenous malformations screening: does any bubble matter? European Journal of Echocardiography. 2009; 10: 513-518. DISCLOSURE: The following authors have nothing to disclose: Lydia Winnicka, Charumathi Raghu Subramanian, Amirahwaty Abdullah, Amirtha Dileepan, James Walsh No Product/Research Disclosure Information

Screening children for pulmonary arteriovenous malformations: Evaluation of 18 years of experience.

Hereditary Hemorrhagic Telangiectasia (HHT) is an autosomal dominant disease with multi-systemic vascular dysplasia. Early diagnosis through screening is important to prevent serious complications. How best to screen children of affected parents for pulmonary arteriovenous malformations (PAVMs) is often subject to debate. Transthoracic contrast echocardiogram (TTCE) is considered optimal in screening for PAVMs in adults. Guidelines for the screening of children are not specific, reflecting the lack of scientific evidence on the best method to use. Aims of this study are (i) to evaluate our current screening method, consisting of history, physical examination, pulse oximetry, and chest radiography and (ii) to assess whether postponing more invasive screening for PAVMs until adulthood is safe. This is a prospective observational cohort study using a patient database. Over a period of 18 years (mean follow-up 9.21 years, SD 4.72 years), 436 children from HHT families were screened consecutively. A total of 175/436 (40%) children had a diagnosis of HHT. PAVMs were detected in 39/175 (22%) children, 33/39 requiring treatment by embolotherapy. None of the screened children suffered any PAVM-associated complications with this screening method. This study shows that a conservative screening method during childhood is sufficient to detect large PAVMs and protect children with HHT for PAVM-related complications. Postponing TTCE and subsequent chest CT scanning until adulthood to detect any smaller PAVMs does not appear to be associated with major risk.

A Survey of Pulmonary Arteriovenous Malformation Screening, Management, and Follow-Up in Hereditary Hemorrhagic Telangiectasia Centers of Excellence.

To determine current practice regarding screening, management, and follow-up of pulmonary arteriovenous malformations (PAVMs), particularly those with feeding arteries <3mm in diameter, in those patients with hereditary hemorrhagic telangiectasia (HHT) at HHT Centers of Excellence. A 32-question survey focusing on PAVM screening, management, and follow-up was sent to 147 participants at HHT Centers worldwide. Thirty-three responses were received (22%); 60% from interventional radiologists and 20% from pulmonologists; 67% from the USA, 21% European, and 6% Asian. In HHT patients with initial negative screening echocardiogram, 60% recommended repeat screening contrast echocardiogram in 5years, while 15% felt that no additional screening was necessary in these patients. Fifty-nine percentage reported never having seen a patient with initial negative contrast echocardiogram become positive. In patients with grade 1 echocardiograms, 41% recommended contrast-enhanced CT as the next step in management, 22% recommended non-contrast CT, and 22 and 3% recommended repeat echocardiogram in 5 and 10years, respectively. In patients with grade 1 echocardiograms but no visible PAVMs, opinions regarding the use of bubble filters were evenly divided, while 79% recommended prophylactic antibiotics prior to invasive procedures. Eighty percentages of respondents treat PAVMs with feeding artery less than 3mm, and 52% treat feeders less than 2mm. Regarding follow-up, 71% reported seeing PAVM recurrence at the site of a previously completely treated PAVM. There is inconsistency in practice regarding PAVM screening, management, and follow-up, suggesting a need for further research and guideline development.

Non-invasive CT screening for pulmonary arteriovenous malformations in children with confirmed hereditary hemorrhagic telangiectasia: Results from two pediatric centers.

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant genetic disorder that is caused by mutations in mainly two genes, that is ENG, encoding endoglin (HHT1), or ACVRL1, encoding activin receptor-like kinase 1 (ALK-1/HHT2). HHT is characterized by recurrent epistaxis, mucocutaneous telangiectasia, and vascular visceral dysplasia responsible for visceral arteriovenous malformations (AVM). to report the experience of two university hospitals (Trousseau, Paris, and CHIC, Creteil) with screening children for HHT and pulmonary AVM (PAVM) using high resolution computed tomography (HRCT). parents with confirmed HHT were offered to have their children screened for the mutation identified in their family, and informed consent was obtained. Children carrying the same mutation as their parents underwent HRCT of the chest without contrast. between 2008 and 2015, 99 children were screened for HHT mutations. Mutations were identified in 59 patients, that is 24 HHT1 and 35 HHT2. Radiologic and clinical screening was possible in 52 patients (21 HHT-1 and 31 HHT-2). Among those, PAVM was identified in 13 patients (25%; n = 8 HHT1; n = 5 HHT2), and four of them required embolization therapy. This study highlights the usefulness of genetic screening in children with known HHT family. It also suggests that a non-invasive protocol such as HRTC is an efficient approach to detect non-symptomatic lesions that are present early on in children carrying the ENG (HHT1), but also the ACVRL1 mutations (HHT2). Pediatr Pulmonol. 2017;52:642-649. © 2017 Wiley Periodicals, Inc.

Screening for arteriovenous malformations in hereditary haemorrhagic telangiectasia.

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. 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. 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. 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.

ACR Appropriateness Criteria Clinically Suspected Pulmonary Arteriovenous Malformation

Pulmonary arteriovenous malformations are often included in the differential diagnosis of common clinical presentations, including hypoxemia, hemoptysis, brain abscesses, and paradoxical stroke, as well as affecting 30% to 50% of patients with hereditary hemorrhagic telangiectasia (HHT). Various imaging studies are used in the diagnostic and screening settings, which have been reviewed by the ACR Appropriateness Criteria Vascular Imaging Panel. Pulmonary arteriovenous malformation screening in patients with HHT is commonly performed with transthoracic echocardiographic bubble study, followed by CT for positive cases. Although transthoracic echocardiographic bubble studies and radionuclide perfusion detect right-to-left shunts, they do not provide all of the information needed for treatment planning and may remain positive after embolization. Pulmonary angiography is appropriate for preintervention planning but not as an initial test. MR angiography has a potential role in younger patients with HHT who may require lifelong surveillance, despite lower spatial resolution compared with CT.The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every three years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Screening pulmonary arteriovenous malformations in a large cohort of Spanish patients with hemorrhagic hereditary telangiectasia

Background and objectivesBecause of the serious nature of potential complications, screening for pulmonary arteriovenous malformations is required in patients with hereditary hemorrhagic telangiectasia. The aim of this study was to evaluate the utility of contrast echocardiography and compare the performance of two contrast agents: agitated saline and Gelofusine. Material and methodsTwo hundred and five patients screened for PAVMs using TTCE and computed tomography (CT) performed with an interval of less than 180days. Contrast echocardiography studies were graded on a 4-point semiquantitative scale based on the amount of microbubbles seen in left heart chambers. ResultsPositive TTCE findings were seen in 137 (66.8%) patients, whereas CT confirmed PAVMs in 59 (43.1%). Two of 67 grade 1 patients; 18 of 42 grade 2; 17 of 22 grade 3 and all grade 4 had PAVMs on CT. Embolotherapy was feasible in 38.9% patients in grade 2 and 82.3% and 95.2% in grades 3–4. No patients in grade 1 were embolized. The mean cardiac cycle in which bubbles were first seen in the left heart in patients without and with PAVMs on CT was 6.1 and 3.9 (p<0.0001). Compared to saline, Gelofusine produced an overall increase in grade. ConclusionsNo grade 1 patients had treatable PAVMs. There is a need for improvement in the selection of patients for CT in grade 2, where less than half have PAVMs on CT. The cardiac cycle may help to differentiate between patients with and without PAVMs. Gelofusine was not better than saline for PAVM screening.

How to manage patients with hereditary haemorrhagic telangiectasia.

Hereditary haemorrhagic telangiectasia is a rare systemic autosomal dominantly inherited disorder of the fibrovascular tissue with a wide variety of clinical manifestations. Diagnosis is based on the clinical Curaçao criteria or molecular genetic testing. Dilated vessels can develop into telangiectases or larger vascular malformations in various organs, calling for an interdisciplinary approach. Epistaxis and gastrointestinal bleeding can result from these vascular defects. Various conservative and interventional treatments have been described for these conditions. However, no optimal therapy exists. Treatment can become especially difficult due to progressive anaemia or when anticoagulant or anti-thrombotic therapy becomes necessary. Screening for pulmonary arteriovenous malformations (PAVM) should be performed in all confirmed and suspected patients. Treatment by percutaneous transcatheter embolotherapy and antibiotic prophylaxis is normally effective for PAVM. Cerebral or hepatic vascular malformations and rare manifestations need to be evaluated on a case-by-case basis to determine the best course of action for treatment.

Carotid ultrasound for pulmonary arteriovenous malformation screening

ObjectiveIn patients with hereditary hemorrhagic telangiectasia (HHT), pulmonary arteriovenous malformations (PAVMs) can cause serious neurological complications. Our aim was to evaluate the potential of contrast-enhanced Doppler ultrasound (CE-US) of the common carotid artery as a screening test for detection of PAVMs.MethodsA total of 124 consecutive patients with HHT or a positive family history underwent screening for PAVMs with CE-US and thoracic contrast-enhanced magnetic resonance angiography (CE-MRA). CE-US was performed after receiving (D)-galactose microparticulate, and CE-MRA with gadobenate dimeglumine. Twenty-five patients with confirmed PAVMs were referred to conventional pulmonary catheter angiography (PA). Findings on CE-US and CE-MRA were evaluated using contingency tables and McNemar’s test.ResultsUsing CE-MRA as the reference test, CE-US had a sensitivity of 100%, a specificity of 87%, and a negative predictive value of 100%. In 25 patients who underwent PA, PAVMs that had been diagnosed on CE-US and CE-MRA were confirmed. Of the PAVMs detected by CE-MRA, 24% were not identified on PA.ConclusionCE-US is a simple, minimally invasive screening method that can easily be performed in different settings. CE-US can predict PAVMs with high probability of success. CE-US may be a simple alternative to transthoracic echocardiography in the assessment of PAVMs in certain HHT-patients.

Transthoracic contrast echocardiography for detection of pulmonary arteriovenous malformations in hereditary hemorrhagic telangiectasia: How can the process be improved for patient safety?

Introduction: Patients with hereditary hemorrhagic telangiectasia (HHT) are at risk for pulmonary arteriovenous malformations (PAVMs). Extracardiac right-to-left shunts due to PAVMs can lead to systemic emboli; clinical sequelae including strokes and brain abscesses. Regular screening is required, with appropriate medical/interventional management to alleviate morbidity and mortality from PAVMs. International HHT guidelines recommend standardized transthoracic contrast echocardiogram (TTCE) with agitated saline (in an HHT Foundation-accredited laboratory) as the initial screening test, and, when needed, non-contrast computerized tomography of the chest (CT Chest) to follow up on a positive TTCE. Case presentation: A 40-year-old woman was seen for evaluation of HHT and referred for TTCE as part of her PAVM screen. Following administration of agitated saline, she developed a headache, visual changes in her right eye, and right arm weakness, followed by posturing and stiffness in her right arm. Her symptoms resolved after five minutes, consistent with a transient ischemic attack (TIA). Clinical impact: Protocols at our institution were amended following this index case and echocardiography laboratory protocols were adjusted to use a maximum of 0.1 cc air to 9.9 cc saline for TTCE studies in the HHT population. Only the attending echocardiologist who is familiar with possible systemic air embolism during bubble contrast echocardiography in patients with HHT should perform agitation and infusion of contrast and should directly review the images for appropriate visualization during the exam for this test to be appropriately interpreted. Paradoxical emboli due to right-to-left shunt are important to recognize. Best practice for PAVM screening in HHT patients includes use of standardized protocols for the performance and reporting of TTCE in the evaluation of pulmonary shunts.

P83 Should children from HHT families undergo screening thoracic CT scans for the diagnosis of pulmonary arteriovenous malformations? Survey data on breast cancer incidence

BackgroundLimiting thoracic radiation burden is a driving force for development of diagnostics, with the use of childhood CT scans particularly linked to increased cancer incidence [1]. Imaging of children with...

Pulmonary Arteriovenous Malformations

Pulmonary arteriovenous malformations (PAVMs) are abnormal vascular structures that most often connect a pulmonary artery to a pulmonary vein, bypassing the normal pulmonary capillary bed and resulting in an intrapulmonary right-to-left shunt. As a consequence, patients with PAVM can have hypoxemia and paradoxical embolization complications, including stroke and brain abscess. PAVMs may be single or multiple, unilateral or bilateral, and simple or complex. Most PAVMs are hereditary and occur in hereditary hemorrhagic telangiectasia, an autosomal dominant vascular disorder, and screening for PAVM is indicated in this subgroup. PAVMs may also be idiopathic, occur as a result of trauma and infection, or be secondary to hepatopulmonary syndrome and bidirectional cavopulmonary shunting. Diagnostic testing involves identifying an intrapulmonary shunt, with the most sensitive test being transthoracic contrast echocardiography. Chest CT scan is useful in characterizing PAVM in patients with positive intrapulmonary shunting. Transcatheter embolotherapy is the treatment of choice for PAVM. Lifelong follow-up is important because recanalization and collateralization may occur after embolization therapy. Surgical resection is rarely necessary and reserved for patients who are not candidates for embolization. Antibiotic prophylaxis for procedures with a risk of bacteremia (eg, dental procedures) is recommended in all patients with PAVM because of the risk of cerebral abscess.