Guideline sources The following summarized guidelines for the evaluation and management of pulmonary arteriovenous malformations (PAVM) are prepared by our editorial team based on guidelines from the Hereditary Haemorrhagic Telangiectasia Working Group (HHT-WG 2020), the British Thoracic Society (BTS 2017), and the American College of Radiology (ACR 2016). 1 2 3 Guidelines 1. Screening and diagnosis Indications for screening, patients: As per HHT-WG 2020 guidelines, screen all patients with possible or confirmed HHT for pulmonary AVMs. B Show 3 more As per BTS 2017 guidelines, consider screening all > 16 years old patients with known or suspected HHT for pulmonary AVMs. E Show 5 more https://web.pathway.md/diseases/recxiVxG6u69NrmQB 1/5 6/29/23, 11:35 PM Pulmonary arteriovenous malformations Pathway Show 5 more Indications for screening (family relatives): Recognize that first-degree family members (parent, sibling or child) of patients with pulmonary AVMs due to HHT are at ~1 in 4 risk of pulmonary AVMs. Recognize that this risk only falls to general population figures if the relative has a gene test excluding the HHT pathogenic gene variant ('mutation') present in the family. E Obtain clinical screening in first-degree relatives of patients with pulmonary AVMs, unless pulmonary AVM is solitary and there is no suspicion of a hereditary vascular condition, such as HHT. E 2. Diagnostic investigations Diagnostic imaging: As per HHT-WG 2020 guidelines: Consider obtaining contrast TTE as initial screening test for pulmonary AVMs. C Obtain low-dose non-contrast chest CT for diagnostic testing in pregnant patients with HHT and symptoms suggestive of pulmonary AVM (at any gestational age, as clinically indicated). B As per ACR 2016 guidelines, consider obtaining CXR complementary to TTE. C Show 4 more Screening for hereditary hemorrhagic telangiectasia: As per BTS 2017 guidelines, take into account the possibility of HHT in all patients with pulmonary AVMs and sporadic etiology only in patients with single pulmonary AVM. E Show 4 more As per ACR 2016 guidelines, obtain TTE bubble study for initial screening of HHT, followed by thin-section (1-2 mm) CT in positive patients. 3. Respiratory support Supplemental oxygen: Recognize that despite oxygenation parameters that would fulfil requirements for supplementary oxygen in other clinical settings, patients with hypoxemia due to pulmonary AVMs usually display good exercise capacity, flight tolerance and successful pregnancies, assuming normal physiological compensations can operate. E Do not offer supplementary oxygen in asymptomatic, hypoxemic patients with pulmonary AVMs. D 4. Medical management Antiplatelet therapy: Consider initiating antiplatelet agents in patients with pulmonary AVMs, as they are at increased risk of ischemic stroke. E https://web.pathway.md/diseases/recxiVxG6u69NrmQB 2/5 6/29/23, 11:35 PM Pulmonary arteriovenous malformations Pathway Recognize that the safety of thrombolysis is not established in patients with pulmonary AVMs. E Preprocedural antibiotic prophylaxis: offer prophylactic antibiotics before dental, endoscopic, surgical and other interventional procedures that could lead to transient bacteremias in patients with pulmonary AVMs. E 5. Nonpharmacologic interventions Dental hygiene: advise judicious dental hygiene in patients with pulmonary AVMs. E Iron supplementation: consider administering iron supplementation in hypoxemic patients even if the Hgb is in the normal range. Recognize that microcytic and/or hypochromic red cell indices suggest iron deficiency that is not excluded by a normal serum ferritin. E Rest: do not offer bed rest, exercise limitation, or hospitalization in asymptomatic, hypoxemic patients with pulmonary AVMs. D 6. Therapeutic procedures Transcatheter embolotherapy: As per HHT-WG 2020 guidelines, perform transcatheter embolotherapy for the treatment of pulmonary AVMs in patients with HHT. B As per BTS 2017 guidelines, consider referring all patients with radiographically-visible pulmonary AVMs to interventional specialists experienced in pulmonary AVMs embolization. E Show 3 more As per ACR 2016 guidelines, perform pulmonary angiography with concurrent transcatheter embolization for the treatment of patients with pulmonary AVMs. Therapeutic venesection: Do not perform prophylactic venesection in asymptomatic patients with pulmonary AVMs with a high hematocrit. D Consider performing venesection (isovolemic) only if there are symptoms of hyperviscosity as for patients with cyanotic congenital heart disease. E 7. Surgical interventions Lung resection: consider performing limited surgical resection if patients with pulmonary AVMs are unsuitable for embolization. E Lung transplantation: do not perform lung transplantation in patients with uncomplicated pulmonary AVMs. D 8. Specific circumstances https://web.pathway.md/diseases/recxiVxG6u69NrmQB 3/5 6/29/23, 11:35 PM Pulmonary arteriovenous malformations Pathway Pediatric patients: treat large pulmonary ateriovenous malformations and pulmonary ateriovenous malformations associated with reduced oxygen saturation in pediatric patients to avoid serious complications. B Pregnant patients: As per HHT-WG 2020 guidelines: Treat pulmonary AVMs in patients with HHT starting in the second trimester unless otherwise clinically indicated. B Manage pregnant patients with HHT at a tertiary care center by a multidisciplinary team if they have an untreated pulmonary AVM or have not been recently screened for pulmonary AVM. B As per BTS 2017 guidelines: Recognize that the majority of pregnancies in patients with pulmonary AVMs proceed normally even in the setting of significant hypoxemia. E Manage pregnant patients with pulmonary AVMs as high-risk pregnancies involving a multiprofessional approach, as there is a 1% risk of maternal death. E 9. Patient education General counseling: Provide the following long-term advices in patients with documented pulmonary ateriovenous malformations (treated or untreated): take antibiotic prophylaxis for procedures with risks of bacteremia take extra care to avoid IV air when IV access is in place avoid scuba diving. B 10. Follow-up and surveillance Follow-up, general principles: As per HHT-WG 2020 guidelines, provide long-term follow-up in patients with pulmonary ateriovenous malformations in order to detect growth of untreated pulmonary ateriovenous malformations and also reperfusion of treated ateriovenous malformations. B As per BTS 2017 guidelines: Avoid obtaining routine follow-up CT in patients with pulmonary AVMs. D Consider obtaining repeated CT if there is clinical suspicion of the development or increase in size of pulmonary AVMs based on symptoms, pulse oximetry, CXR, right-to-left shunt evaluations by contrast echocardiography or the clinical scenario, for example, after pregnancy. E Follow-up (treated PAVMs): obtain follow-up approximately 6 months after treatment to assess clinical, physiological (SaO , Hgb and CaO2) and radiological responses in patients with pulmonary AVMs that have been recently embolized or resected. E Show 2 more Follow-up (residual or untreated PAVMs): implement a holistic approach for follow-up with a combination of primary or secondary care, depending on specific clinical circumstances and https://web.pathway.md/diseases/recxiVxG6u69NrmQB 4/5 6/29/23, 11:35 PM Pulmonary arteriovenous malformations Pathway local expertise, in patients with residual or untreated pulmonary AVMs. E Show 3 more Clinical findings Symptoms Past medical history Chest pain Brain abscess Cough Cerebral AVMs Exertional dyspnea HHT Fainting Hepatic VMs Headache Migraine-type headache Hemoptysis Stroke Nosebleed TIA Numbness Lab findings Palpitations Paresthesia blood oxygen Vertigo Integument exam Cyanosis Digital clubbing Imaging findings Lung nodule References 1. Marie E Faughnan, Johannes J Mager, Steven W Hetts et al. Second International Guidelines for the Diagnosis and Management of Hereditary Hemorrhagic Telangiectasia. Ann Intern Med. 2020 Dec 15;173 12 989 1001. Open 2. Claire L Shovlin, Robin Condliffe, James W Donaldson et al. British Thoracic Society Clinical Statement on Pulmonary Arteriovenous Malformations. Thorax. 2017 Dec;72 12 1154 1163. Open 3. Michael Hanley, Osmanuddin Ahmed, Ankur Chandra et al. ACR Appropriateness Criteria Clinically Suspected Pulmonary Arteriovenous Malformation. J Am Coll Radiol. 2016 Jul;13 7 796 800. Open https://web.pathway.md/diseases/recxiVxG6u69NrmQB 5/5