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)

• A Practical Approach to Chronic Thromboembolic Pulmonary Hypertension

  Chronic thromboembolic pulmonary hypertension (CTEPH) is a serious but potentially treatable form of pulmonary hypertension caused by persistent organised clot and progressive small-vessel disease. It may develop after an acute pulmonary embolism, although some patients have no recognised history of venous thromboembolism.

  For clinicians in Australia, early recognition matters because definitive assessment often requires referral to a specialist pulmonary hypertension service. Coordinated input from respiratory physicians, cardiologists, radiologists, haematologists, surgeons and interventional teams can determine whether pulmonary endarterectomy, balloon pulmonary angioplasty or medical therapy offers the best outcome.

  Recognise When CTEPH Should Be Suspected

  CTEPH should be considered when breathlessness, reduced exercise tolerance, chest discomfort, dizziness or syncope persists after pulmonary embolism. Symptoms may be attributed to deconditioning, asthma, obesity or cardiac disease, delaying referral. A declining six-minute walk distance, signs of right-heart strain or disproportionate dyspnoea should increase suspicion.

  The diagnosis can also occur without a clearly documented acute embolic event. Risk factors include recurrent venous thromboembolism, splenectomy, inflammatory conditions, malignancy, myeloproliferative disease and antiphospholipid syndrome. Persistent symptoms after at least three months of effective anticoagulation warrant reassessment rather than indefinite observation.

  Initial evaluation includes a careful history, examination, electrocardiography, chest imaging, echocardiography and basic blood tests. Echocardiography may show right ventricular enlargement, reduced right ventricular function or elevated estimated pulmonary artery pressure, but it cannot confirm or exclude CTEPH by itself.

  Confirm the Diagnosis and Map the Disease

  A ventilation–perfusion scan is the preferred screening test for chronic thromboembolic disease. Multiple mismatched perfusion defects support the diagnosis and should prompt referral to a pulmonary hypertension centre. A normal or near-normal scan makes clinically important CTEPH unlikely, although interpretation must account for technical quality and coexisting lung disease.

  Computed tomography pulmonary angiography helps define webs, bands, pouch lesions, ring stenoses and complete vascular obstruction. Conventional pulmonary angiography or advanced catheter-based imaging may be required when disease is subtle or when intervention is being planned. The imaging question is not simply whether clot exists, but whether the obstruction is technically accessible.

  Right-heart catheterisation confirms haemodynamics. Current definitions of pulmonary hypertension use a mean pulmonary artery pressure above 20 mmHg, with pulmonary vascular resistance above 2 Wood units and a pulmonary artery wedge pressure of 15 mmHg or less for precapillary disease. Results must be interpreted alongside left-heart function, lung disease and the quality of the wedge-pressure measurement.

  Assess Operability and Clinical Risk

  Pulmonary endarterectomy is the treatment of choice for suitable patients with surgically accessible disease. It removes organised material from the pulmonary arteries and can substantially improve symptoms, pulmonary pressures, right ventricular function and survival. Operability depends on the distribution of obstruction, haemodynamic burden, comorbidities and the relationship between disease severity and visible vascular lesions.

  A patient may be considered inoperable because disease is too distal, surgical risk is excessive or pulmonary vascular remodelling is disproportionate to the obstructive lesions. This decision should be made by an experienced multidisciplinary team rather than from a single scan or a local surgical opinion.

  Risk assessment includes functional class, exercise capacity, right ventricular performance, biomarkers such as NT-proBNP, renal function, oxygenation and haemodynamic severity. Frailty, obesity, sleep-disordered breathing and coronary disease are particularly relevant when planning major surgery or catheter-based treatment.

  Select Treatment at an Expert Centre

  Patients with operable CTEPH should be referred promptly to a centre with experience in pulmonary endarterectomy. Treatment should not be postponed while symptoms are managed repeatedly with diuretics or general pulmonary hypertension therapy. Diuretics may relieve congestion, but they do not remove the mechanical obstruction.

  Balloon pulmonary angioplasty is an important option for selected patients with inoperable or residual disease, especially when lesions are suitable for staged catheter treatment. Several sessions may be needed, with careful monitoring for reperfusion pulmonary oedema, vascular injury and contrast-related complications.

  Targeted medical therapy may be used for inoperable CTEPH or persistent or recurrent pulmonary hypertension after surgery. Riociguat is an established therapy in these settings, subject to specialist prescribing, regulatory requirements and local access arrangements. In Australia, availability through the Pharmaceutical Benefits Scheme and hospital pathways can vary, so treatment planning should involve the relevant pulmonary hypertension service.

  Manage Anticoagulation and Associated Conditions

  Lifelong therapeutic anticoagulation is generally required because the underlying thromboembolic tendency remains important even after endarterectomy or successful angioplasty. The choice between a vitamin K antagonist and a direct oral anticoagulant depends on renal function, bleeding risk, drug interactions, adherence, pregnancy considerations and the presence of antiphospholipid syndrome.

  A vitamin K antagonist is generally preferred for patients with antiphospholipid syndrome, particularly those with high-risk antibody profiles. Anticoagulation should be reviewed around invasive procedures and coordinated with haematology when thrombosis and bleeding risks are difficult to balance. Patients should receive clear advice about missed doses, over-the-counter medicines and bleeding symptoms.

  Treatable contributors to breathlessness should be addressed in parallel. These include iron deficiency, obstructive sleep apnoea, chronic lung disease, arrhythmia, systemic hypertension and vaccination gaps. Smoking cessation, graded rehabilitation, nutrition and activity advice should reflect the person’s functional capacity rather than impose unrealistic targets.

  Coordinate Long-Term Care in Australia

  Care is often shared between a specialist service and a local general practitioner. Patients in regional or remote areas may need telehealth, coordinated imaging and travel support to reach centres in Sydney, Melbourne, Brisbane, Perth or Adelaide. The distances involved can affect follow-up, rehabilitation attendance and access to repeated balloon procedures.

  Australian prescribing and funding arrangements should be explained early. Medicare supports many consultations and investigations, but out-of-pocket costs, private imaging fees and travel expenses vary. PBS eligibility, hospital formulary rules and access to specialised medicines should be checked by the treating team rather than assumed.

  Patients should be reviewed for symptoms, exercise capacity, right ventricular function, oxygen needs, anticoagulation safety and recurrence of pulmonary hypertension. Care plans should also account for practical routines, such as hot weather in northern Australia, long-distance driving, bushwalking and physically demanding work. Advice about fluid intake, exertion and travel should be individualised, particularly when right-heart failure is present.

  Treatment Choices at a Glance

  Approach	Best suited to	Main purpose	Key considerations
  Pulmonary endarterectomy	Surgically accessible chronic obstruction	Remove organised clot and restore blood flow	Requires expert surgical assessment and perioperative care
  Balloon pulmonary angioplasty	Inoperable or residual lesions suitable for catheter treatment	Dilate obstructed pulmonary arteries	Usually staged; complications require experienced operators
  Targeted medical therapy	Inoperable disease or persistent pulmonary hypertension	Reduce pulmonary vascular resistance and symptoms	Specialist prescribing, monitoring and access requirements
  Anticoagulation	Nearly all confirmed CTEPH patients	Prevent recurrent venous thromboembolism	Usually lifelong; choice depends on comorbidity and bleeding risk
  Rehabilitation and supportive care	Most patients, alongside definitive therapy	Improve conditioning, function and quality of life	Must be paced according to right-heart status and oxygenation

  Practical Priorities for Clinicians

  • Reconsider CTEPH when breathlessness persists after pulmonary embolism.
  • Request a ventilation–perfusion scan when chronic thromboembolic disease is suspected.
  • Refer early to a multidisciplinary pulmonary hypertension centre.
  • Continue and review therapeutic anticoagulation unless a specialist identifies a clear contraindication.
  • Assess operability before relying on long-term medical treatment.
  • Address sleep apnoea, iron deficiency, lung disease, deconditioning and psychosocial barriers.
  • Build a follow-up plan that accounts for Australian travel distances, Medicare and PBS pathways.

  The key point is that persistent symptoms after pulmonary embolism should trigger structured reassessment. CTEPH is defined by more than residual clot on a scan: diagnosis requires compatible symptoms, chronic vascular obstruction, pulmonary haemodynamics and expert interpretation. Early referral creates the best opportunity to match each patient with endarterectomy, balloon angioplasty, medical therapy and lifelong coordinated care.

  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)