Population Covered By The Guidance
This pathway provides guidance on the imaging of adult patients with suspected chronic thromboembolic pulmonary hypertension.
Lead Researcher: Aian Chin
Experts & Contributors: Weng Soon Chin, Ravinder Dhillon, Ashu Gupta, Rachael O’Rourke, Teck Siew, Mark Teh, Yuranga Weerakkody
Date reviewed: November 2018
Date Published: March 2019
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- A diagnosis of CTEPH was previously associated with a poor prognosis, however it is now potentially curable with surgery or balloon pulmonary angioplasty. Improvements in medical and endovascular treatments have led to some improved survival in inoperable or refractory CTEPH
- Lung scintigraphy (V/Q or ventilation/perfusion scan) is the first-imaging modality to investigate suspected CTEPH. A normal V/Q scan rules out a diagnosis of CTEPH with high certainty. CTEPH may still be present with an intermediate scan
- CT pulmonary angiography (CTPA) alone frequently misses the diagnosis of CTEPH so it is not recommended to rule it out
- Possible cases of CTEPH or pulmonary hypertension due to other causes should be referred to a specialist centre for further evaluation
- Transthoracic echocardiogram (TTE) may suggest pulmonary hypertension, but invasive measurement of right heart pressures and pulmonary artery wedge pressures with right heart catheterisation is required to confirm the diagnosis
- The role of CTPA or magnetic resonance pulmonary angiography (MRPA) and cardiac MRI is to assess disease severity, distribution and location to allow planning for surgery or radiological interventions and to assess right ventricular volume and function as a marker for treatment response. The chance of success with surgery is greatest when vascular obstruction is present in the main pulmonary arteries or lobar arteries. Balloon pulmonary angioplasty is successful at treating segmental and subsegmental arteries
- Catheter pulmonary angiography remains the gold standard for diagnosis and treatment work up and all patients require this to plan intervention
References are graded from Level I to V according to the Oxford Centre for Evidence-Based Medicine, Levels of Evidence. Download the document
- Ende-Verhaar YM, Cannegieter SC, Vonk Noordegraaf A, Delcroix M, Pruszczyk P, Mairuhu AT, et al. Incidence of chronic thromboembolic pulmonary hypertension after acute pulmonary embolism: a contemporary view of the published literature. Eur Respir J. 2017;49(2) (Level I evidence). View the reference
- Condliffe R, Kiely DG, Gibbs JS, Corris PA, Peacock AJ, Jenkins DP, et al. Prognostic and aetiological factors in chronic thromboembolic pulmonary hypertension. Eur Respir J. 2009;33(2):332-8. (Level III evidence). View the reference
- Delcroix M, Lang I, Pepke-Zaba J, Jansa P, D'Armini AM, Snijder R, et al. Long-term outcome of patients with chronic thromboembolic pulmonary hypertension: results from an international prospective registry. Circulation. 2016;133(9):859-71. (Level II evidence). View the reference
- Pepke-Zaba J, Delcroix M, Lang I, Mayer E, Jansa P, Ambroz D, et al. Chronic thromboembolic pulmonary hypertension (CTEPH): results from an international prospective registry. Circulation. 2011;124(18):1973-81. (Level II evidence). View the reference
- Galie N, Humbert M, Vachiery JL, Gibbs S, Lang I, Torbicki A, et al. 2015 ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension: the joint task force for the diagnosis and treatment of pulmonary hypertension of the European Society of Cardiology (ESC) and the European Respiratory Society (ERS): endorsed by: Association for European Paediatric and Congenital Cardiology (AEPC), International Society for Heart and Lung Transplantation (ISHLT). Eur Heart J. 2016;37(1):67-119. (Guideline). View the reference
- Konstantinides SV, Torbicki A, Agnelli G, Danchin N, Fitzmaurice D, Galie N, et al. 2014 ESC guidelines on the diagnosis and management of acute pulmonary embolism. Eur Heart J. 2014;35(43):3033-69, 69a-69k. (Guideline). View the reference
- Lang IM, Simonneau G, Pepke-Zaba JW, Mayer E, Ambroz D, Blanco I, et al. Factors associated with diagnosis and operability of chronic thromboembolic pulmonary hypertension. A case-control study. Thromb Haemost. 2013;110(1):83-91. (Level III evidence) View the reference
- Pengo V, Lensing AWA, Prins MH, Marchiori A, Davidson BL, Tiozzo F, et al. Incidence of chronic thromboembolic pulmonary hypertension after pulmonary embolism. N Engl J Med. 2004;350(22):2257-64. (Level II evidence). View the reference
- Tunariu N, Gibbs SJ, Win Z, Gin-Sing W, Graham A, Gishen P, et al. Ventilation-perfusion scintigraphy is more sensitive than multidetector CTPA in detecting chronic thromboembolic pulmonary disease as a treatable cause of pulmonary hypertension. J Nucl Med. 2007;48(5):680-4. (Level II-III evidence). View the reference
- Worsley DF, Palevsky HI, Alavi A. Ventilation-perfusion lung scanning in the evaluation of pulmonary hypertension. J Nucl Med. 1994;35(5):793-6. (Level II-III evidence). View the reference
- Rajaram S, Swift AJ, Telfer A, Hurdman J, Marshall H, Lorenz E, et al. 3D contrast-enhanced lung perfusion MRI is an effective screening tool for chronic thromboembolic pulmonary hypertension: results from the ASPIRE Registry. Thorax. 2013;68(7):677-8. (Level II-III evidence). View the reference
- Donkers-van Rossum AB. Diagnostic strategies for suspected pulmonary embolism. The European respiratory journal. 2001;18(3):589-97. (Review article). View the reference
- Klok FA, Delcroix M, Bogaard HJ. Chronic thromboembolic pulmonary hypertension from the perspective of patients with pulmonary embolism. J Thromb Haemost. 2018 (Review article). View the reference
- Litmanovich D, Tack D, Lin PJ, Boiselle PM, Raptopoulos V, Bankier AA. Female breast, lung, and pelvic organ radiation from dose-reduced 64-MDCT thoracic examination protocols: a phantom study. AJR American journal of roentgenology. 2011;197(4):929-34. (Level III evidence). View the reference
- Szucs-Farkas Z, Schibler F, Cullmann J, Torrente JC, Patak MA, Raible S, et al. Diagnostic accuracy of pulmonary CT angiography at low tube voltage: intraindividual comparison of a normal-dose protocol at 120 kVp and a low-dose protocol at 80 kVp using reduced amount of contrast medium in a simulation study. AJR American journal of roentgenology. 2011;197(5):W852-9. (Level III evidence). View the reference
- Szucs-Farkas Z, Kurmann L, Strautz T, Patak MA, Vock P, Schindera ST. Patient exposure and image quality of low-dose pulmonary computed tomography angiography: comparison of 100- and 80-kVp protocols. Investigative radiology. 2008;43(12):871-6. (Level III evidence). View the reference
- Zamboni GA, Guariglia S, Bonfante A, Martino C, Cavedon C, Mucelli RP. Low voltage CTPA for patients with suspected pulmonary embolism. European journal of radiology. 2012;81(4):e580-4. (Level III evidence). View the reference
- Ruggiero A, Screaton NJ. Imaging of acute and chronic thromboembolic disease: state of the art. Clin Radiol. 2017;72(5):375-88. (Review article). View the reference
- Hoeper MM, Lee SH, Voswinckel R, Palazzini M, Jais X, Marinelli A, et al. Complications of right heart catheterization procedures in patients with pulmonary hypertension in experienced centers. J Am Coll Cardiol. 2006;48(12):2546-52. (Level II evidence). View the reference
- Jenkins D. Pulmonary endarterectomy: the potentially curative treatment for patients with chronic thromboembolic pulmonary hypertension. Eur Respir Rev. 2015;24(136):263-71. (Review article). View the reference
- Tanabe N, Kawakami T, Satoh T, Matsubara H, Nakanishi N, Ogino H, et al. Balloon pulmonary angioplasty for chronic thromboembolic pulmonary hypertension: A systematic review. Respiratory investigation. 2018;56(4):332-41. (Review article) View the reference
- Phan K, Jo HE, Xu J, Lau EM. Medical therapy versus balloon angioplasty for CTEPH: A systematic review and meta-analysis. Heart, lung & circulation. 2018;27(1):89-98. (Level I-II evidence) View the reference
- Tamada N, Nakayama K, Yanaka K, Onishi H, Shinkura Y, Tsuboi Y, et al. Early introduction of pulmonary endarterectomy or balloon pulmonary angioplasty contributes to better health-related quality of life in patients with chronic thromboembolic pulmonary hypertension. JACC Cardiovasc Interv. 2018;11(11):1114-6. (Level III evidence) View the reference
- Gopalan D, Delcroix M, Held M. Diagnosis of chronic thromboembolic pulmonary hypertension. Eur Respir Rev. 2017;26(143). (Review article) View the reference
- Rajaram S, Swift AJ, Capener D, Telfer A, Davies C, Hill C, et al. Diagnostic accuracy of contrast-enhanced MR angiography and unenhanced proton MR imaging compared with CT pulmonary angiography in chronic thromboembolic pulmonary hypertension. Eur Radiol. 2012;22(2):310-7. (Level II-III evidence). View the reference
- Berman M, Gopalan D, Sharples L, Screaton N, Maccan C, Sheares K, et al. Right ventricular reverse remodeling after pulmonary endarterectomy: magnetic resonance imaging and clinical and right heart catheterization assessment. Pulmonary Circulation. 2014;4(1):36-44. (Level III evidence) View the reference
Pathway User Guide
Yellow Boxes Denotes extra information. Some contain single or multiple white sub-boxes, click a white box to reveal detailed information in a pop-up.
White Boxes: Denotes standard pathway steps. (If inside a yellow box, they open a specific pop-up).
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The relative radiation level (RRL) of each imaging investigation is displayed in the pop up box.
| SYMBOL | RRL | EFFECTIVE DOSE RANGE |
|---|---|---|
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None | 0 |
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Minimal | < 1 millisieverts |
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Low | 1-5 mSv |
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Medium | 5-10 mSv |
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High | >10 mSv |
Disclaimer
Status Of Recommendations Each pathway is designed to assist clinicians in situations when faced with a large array of possible diagnostic tests and examinations. However, it is recognised that diagnostic practice may differ from a particular pathway depending on local availability of equipment and expertise, as well as the experience of individual clinicians. Therefore each pathway is neither a rigid set of rules, nor a substitute for clinical assessment, and individual patient circumstances should always be considered.
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Lung Scintigraphy (V/Q or ventilation/perfusion scan)
Lung Scintigraphy (V/Q scan)
Recommended first-line diagnostic investigation for CTEPH, can rule out CTEPH with high certainty
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- Lung scintigraphy (V/Q or ventilation/perfusion scan) is the first-imaging modality for CTEPH and can rule out a diagnosis of CTEPH with high certainty
- Originally found to have a significantly higher sensitivity than CTPA (96-97.4% compared to 51%)
- More recent studies with later CT technology have demonstrated comparable sensitivity for V/Q scan and CTPA for CTEPH, so there may be a growing role for CTPA in the future
- Radiolabelled compounds are inhaled for ventilation scanning, whilst perfusion scintigraphy is performed after intravenous injection of technetium-99m macroaggregated albumin. A PE characteristically appears as a pleural based segmental perfusion defect
- Patients with CTEPH show at least one segmental or larger perfusion defect unmatched by ventilation abnormalities
- Visualisation of the vascular bed with CTPA or MRA (or DSA) is still required for treatment decision making following V/Q scan
- Ventilation perfusion scans, compared to CTPA, are associated with lower radiation exposure but the extreme difference between the effective doses as existed previously has been reduced drastically with the new generation MDCT helical scanners that use low dose (using tube currents of 80kVp or 100kVp)
Transthoracic Echocardiogram
Transthoracic Echocardiogram (TTE)
Non-invasive investigation that may indicate the presence of pulmonary hypertension, as well as demonstrate other causes for symptoms and co-existing cardiac disease
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- In patients presenting with dyspnoea following treated PE, echocardiography is recommended as a first-line on-invasive diagnostic investigation for the assessment of pulmonary artery pressures
- TTE also gives information on the presence of structural cardiac abnormalities, valvular dysfunction and systolic or diastolic cardiac function that may contribute to symptoms. Cardiac MRI is the gold standard for assessment of the right ventricle, however it is not widely available
- If TTE findings are compatible with a high or intermediate probability of pulmonary hypertension, a V/Q scan is recommended to exclude CTEPH. However, a positive TTE is not required for diagnosis
- TTE alone is not sufficient to support a treatment decision or to rule out CTEPH in patients with risk factors. If suspected, a V/Q scan should be performed irrespective of TTE
- TTE relies on tricuspid regurgitation of pulmonary arterial hypertension (PAH) and can miss diagnoses. For example, if right heart failure is present, TTE may not demonstrate tricuspid regurgitation despite elevated pulmonary arterial pressures, resulting in false negatives
- Alternatively, pulmonary artery pressures should still be confirmed with right heart catheter because TTE may over-diagnose pulmonary hypertension by up to three times
- In asymptomatic patients with a high risk of CTEPH, V/Q scan may be the diagnostic test of choice to rule out CTEPH
- Some patients have chronic thromboembolic pulmonary disease without PAH. These patients may warrant monitoring as they may develop PAH, although there have been no studies to demonstrate this
Chest Computed Tomography (CT)
Chest Computed Tomography (CT)
Non-contrast thin slices on multislice CT are preferred for assessing lung parenchyma and small airway disease. May reveal a cause for PAH or separate cause for symptoms
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- Non-contrast CT chest can be useful in the work up of pulmonary hypertension to assess the lung parenchyma, which may reveal a cause for PAH or separate cause for symptoms. Can also rule out extrinsic pulmonary vascular compression from other causes such as neoplasm or fibrosis
- Multislice CT (or multidetector CT, MDCT) can be reconstructed into thin slices to assess parenchymal and bronchial detail, and continuous thick slices to assess for small nodules. Multislice CT has a fast acquisition time and high resolution when reconstructed in different planes
CT Pulmonary Angiography (CTPA)
CT Pulmonary Angiography (CTPA)
Non-invasive investigation that may demonstrate evidence of pulmonary embolism
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- May be useful to demonstrate evidence of acute or chronic thromboembolic disease in patients without known history of PE and an indeterminate V/Q scan
- Role of CTPA is well established for the diagnosis of acute PE
- However, CTPA is not recommended to rule out CTEPH due to the high rate of false negatives. CTPA has a significantly lower sensitivity than V/Q scan (51% compared to 96-97.4%)
- Signs of CTEPH on CTPA include direct vascular signs of chronic PE as well as secondary signs including:
- Eccentric, reorganised thrombus
- Webs in pulmonary arteries
- Pulmonary artery stenosis, which can be loss of normal tapering or focal overt stenosis. This is difficult to perceive via CT but is one of the commonest findings
- Pulmonary artery occlusions
- Paucity of distal vessels despite normal parenchyma. This is the cause for mosaic attenuation
- Dilated systemic collaterals
- Evidence of pulmonary hypertension, i.e. central pulmonary artery dilation, right heart dilation and right ventricular hypertrophy with flattening/bowing of the septum to the left, reflux of contrast into hepatic veins
Magnetic Resonance Imaging: Pulmonary Angiography (MRPA or MRA), Pulmonary Perfusion and Cardiac MRI
MR Pulmonary Angiography (MRPA), Pulmonary Perfusion and Cardiac MRI
Reliable investigation to evaluate pulmonary vasculature and distribution of thrombus, if local expertise available. Cardiac MRI is the gold standard for assessing right ventricular function
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- MRA is an excellent non-invasive test to whether CTEPH may be amenable to surgical or endovascular treatment
- MRA can demonstrate flow artefact caused by webs and stenoses which are not detectable on CT
- MR is also able to demonstrate perfusion deficits which correspond to abnormal vessels and defects seen on V/Q scan
- Cardiac MRI is the gold standard for the assessment of right ventricular function and can also assess the myocardium and valve disease
- Gadolinium contrast-enhanced MRA has shown promise for the diagnosis of CTEPH with one study reporting sensitivity and specificity of 98 and 94% respectively
- MRI is especially useful as a baseline for follow-up and monitoring response to treatment
- Unlike CTPA and V/Q scan, there is no exposure to ionising radiation
- Disadvantages:
- Limited availability. MR can be misleading or non-diagnostic if not performed in a high-volume, experienced cardiothoracic imaging centre
- Cost
- Long acquisition time – dyspnoeic patients may not be able to achieve breath hold
- Claustrophobic
- Contraindicated with some ferromagnetic prostheses
Right Heart Catheterisation
Right Heart Catheterisation
Required to confirm the diagnosis of pulmonary arterial hypertension and to evaluate operability
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- Invasive assessment of pulmonary haemodynamics is still required to confirm the diagnosis and to evaluate operability, as TTE may over- or underestimate pulmonary artery pressures
- There is a low associated risk of adverse events, with 1.1% associated morbidity and 0.05% mortality
- Pulmonary hypertension is defined as mean pulmonary artery pressure ≥25mmHg and pulmonary capillary wedge pressure 8
- Symptomatic patients with imaging findings consistent with CTEPH but normal pressures may be considered to have chronic thromboembolic pulmonary vascular disease (CTED). These patients may warrant monitoring for the development of PAH, although the natural history of CTED is unknown and there have been no studies to show that CTED evolves into CTEPH
Catheter Pulmonary Angiography (Digital Subtraction Angiography)
Catheter Pulmonary Angiography
The gold standard for evaluating pulmonary vasculature in CTEPH
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- Invasive investigation that demonstrates the extent and location of disease; indicated to assess whether CTEPH may be amenable to surgical treatment. Also allows for endovascular intervention
- The chance of success with surgery is greatest when vascular obstruction is present in the main pulmonary arteries or lobar arteries
- Balloon pulmonary angioplasty can be used to treat peripheral obstructions in segmental or subsegmental pulmonary branches, and can be undertaken in conjunction with medical therapy. There is growing evidence for BPA as a promising treatment for patients who are unsuitable for surgery