Speaker's Highlight

• Don Sin University of British Columbia, St. Paul Hospital (Canada)
  Kenneth R. Chapman Toronto General Hospital Research Institute (Canada)
• Parameswaran Nair McMaster University (Canada)
  Carolyn Calfee UCSF (U.S.A.)
• Gregory P. Downey University of Colorado School of Medicine (U.S.A.)
  David A. Schwartz University of Colorado School of Medicine (U.S.A.)
• Neil Schluger Tuberculosis Control Branch, California Department of Public Health (U.S.A.)
  Nick Kim Critical Care & Sleep Medicine, University of California San Diego (U.S.A.)
• Nicola Hananiah Baylor College of Medicine (U.S.A.)
  Jae-Joon Yim Seoul National University College of Medicine (Republic of Korea)
• Koichiro Asano Tokai University School of Medicine (Japan)
  Diahn-Warng Perng Taipei Veterans General Hospital (Taiwan)
• Konstantinos Kostikas University of Ioannina (Greece)
  Karin Klooster University Medical Center Groningen (Kingdom of the Netherlands)

• PAVMs in hereditary hemorrhagic telangiectasia

  Pulmonary arteriovenous malformations in hereditary hemorrhagic telangiectasia (HHT) are abnormal connections between pulmonary arteries and veins. HHT is an autosomal-dominant disorder of vascular formation, commonly associated with ENG or ACVRL1 variants; SMAD4-related disease can have a broader phenotype. The central danger is a right-to-left shunt, which lowers arterial oxygen and allows venous thrombi or bacteria to bypass pulmonary filtering and reach the systemic circulation.

  For respiratory clinicians at APSR 2022, PAVMs matter because they can mimic asthma, explain fatigue that does not improve with bronchodilators, and remain silent until hypoxaemia, embolic events, or cerebral infection occurs. A structured HHT assessment brings respiratory medicine, genetics, radiology, interventional radiology, and neurology together rather than treating each vascular complication in isolation.

  Clinical clues and missed diagnoses

  Recognition begins with a combination of recurrent epistaxis, mucocutaneous telangiectasias, unexplained iron-deficiency anaemia, and a first-degree family history. The Curaçao criteria help clinicians weigh these features, while the absence of obvious skin lesions does not exclude HHT. In an Australian family, a parent may describe only occasional nosebleeds; asking about travel, fatigue, breathlessness, and prior paradoxical emboli can reveal the broader pattern. PAVMs themselves may cause exertional dyspnoea, fatigue, cyanosis, platypnoea, or orthodeoxia, and some people are asymptomatic until a serious event occurs.

  Spirometry can be normal, and neither a positive bronchodilator response nor normal spirometry should outweigh a compatible exposure history. Anaemia from recurrent nosebleeds or gastrointestinal bleeding can worsen fatigue, but it does not explain oxygen desaturation produced by a right-to-left shunt. Conversely, PAVMs are not the only explanation for breathlessness; anaemia, asthma, deconditioning, and cardiac disease should be assessed alongside the vascular findings. Pulse oximetry trends and formal exercise testing can help separate fixed shunting from other causes of exertional limitation.

  Screening, imaging and genetic assessment

  When HHT is diagnosed or strongly suspected, contrast-enhanced CT of the chest is commonly used to identify PAVMs, with contrast-enhanced MRI an alternative when appropriate. Imaging defines the feeding artery, sac, and draining vein, which determine embolisation planning. A ventilation-perfusion scan may be preferred in pregnancy or selected cases, while contrast echocardiography can support screening but does not replace anatomical imaging. Local protocols should also address pregnancy, renal impairment, prior contrast exposure, and the need for serial surveillance.

  Genetic testing helps identify familial disease and guide cascade testing, but a negative result does not exclude HHT when the clinical criteria remain convincing. Common genes include ENG, ACVRL1, and SMAD4, with testing and interpretation coordinated through clinical genetics services. Genetic counsellors can support relatives who need screening but may not have obvious telangiectasias. Delegates seeking a wider view of uncommon vascular disorders can consult the linked vascular anomaly resources, while retaining local protocols as the basis for diagnosis and treatment.

  Treatment decisions and longitudinal care

  PAVM treatment balances shunt physiology, embolic risk, symptoms, anatomy, and procedural burden. Under commonly used international guidance, embolisation is generally considered when a feeding artery is 3 mm or larger, or when hypoxaemia or another clinical indication is present; small asymptomatic lesions may be observed under specialist review. The decision should be made in an interventional radiology service with respiratory input, because vascular plugs, coils, and contrast requirements differ between patients. Oxygen can relieve symptoms but does not remove the risk of paradoxical embolisation.

  Feature	Pulmonary AVM	Cerebral AVM	Hepatic involvement
  Typical burden	Exertional hypoxaemia and fatigue	Seizures, headache or intracranial haemorrhage	High-output cardiac failure or portal hypertension
  First-line assessment	Contrast CT or MRI of the chest; V/Q scan when suitable	MRI of the brain and targeted vascular imaging	Doppler ultrasound, with contrast CT or MRI if needed
  Management focus	Embolise a feeding artery of at least 3 mm or treat hypoxaemia; observe selected small lesions	Neurosurgical and endovascular assessment of bleeding and treatment risk	Observation in many cases; selected embolisation or liver-centre management
  Follow-up priority	New PAVMs, residual shunting and oxygen status	Residual aneurysm, seizures and bleeding risk	Cardiac function, liver function and portal complications

  After embolisation, contrast-enhanced imaging is needed to assess residual shunting and detect new lesions because HHT can continue to produce vascular abnormalities. Care coordination should also include dental hygiene, prompt treatment of infection, exercise advice, and planning for pregnancy, major surgery, and prolonged air travel. These issues are particularly relevant to Australians who may live far from a centre with an HHT multidisciplinary team, making a written escalation plan and direct specialist contact valuable.

  Australian systems, access and daily life

  Patients may be referred to major public teaching hospitals in Melbourne, Sydney, Brisbane, Adelaide, and Perth, while Hobart, regional Victoria, central Australia, and northern NSW may depend on shared care or telehealth. Telehealth is useful for family counselling, imaging review, and medication planning, but it cannot replace in-person imaging or embolisation. People in Alice Springs, Darwin, and rural districts may also need transport, accommodation, and time away from work or family when treatment is scheduled.

  Australia’s mixed public and private health market shapes access. Medicare-funded specialist services and diagnostic imaging can reduce costs when the appropriate referral is in place, yet privately supplied scans and hospital episodes may still create out-of-pocket charges. Private health insurance can change those costs, so an estimate is often needed before elective procedures. In public hospitals, specialist consultations and admitted treatment are generally provided without a fee to eligible Medicare beneficiaries; access and waiting times remain important considerations.

  Australian practice also involves regulatory and privacy requirements. Devices used for PAVM embolisation must meet Australian therapeutic goods requirements, generally through inclusion in the Australian Register of Therapeutic Goods, and local distributors plus hospital formularies affect the sizes and types available. For digital follow-up, private-sector health information is handled under the Privacy Act 1988 and applicable state or territory health-records legislation, with consent and secure transfer especially important when scans are shared between cities. Daily life matters too: Australia’s active outdoor culture makes walking, gardening, sport, and long drives common, and exertional symptoms may be mistaken for poor fitness.

  Building a safe care plan

  A safe long-term plan should record the HHT diagnosis, baseline oxygen status, CT or MRI findings, previous embolisation, relevant genetic results, and the date of the next review. Respiratory physicians, clinical geneticists, radiologists, interventional radiologists, neurologists, and nurses can then share a coherent approach. Family members should be offered the appropriate screening pathway, and patients should know which symptoms require urgent assessment, including new neurological signs, significant breathlessness, or suspected infection.

  An immediate practical step for someone with recurrent nosebleeds, unexplained hypoxaemia, or a first-degree family history of HHT is a GP referral to a respiratory or vascular-anomalies service, with previous scans and a three-generation family history prepared for that review.

  Richard Russell Nuffield Department of Clinical Medicine, University of Oxford (United Kingdom)
• Mona Bafadhel King’s College London (United Kingdom)
  David Jackson Guy’s and St Thomas’ Hospital, King’s College London (United Kingdom)
• James Chalmers University of Dundee (United Kingdom)
  David Price University of Aberdeen (United Kingdom)