State-of-the-art chronic thromboembolic pulmonary hypertension diagnosis and management

Abstract

Chronic thromboembolic pulmonary hypertension (CTEPH) is a debilitating disease caused by chronic obstruction of pulmonary artery branches following episodes of pulmonary embolism and incomplete thrombus resolution. The prognosis of patients with CTEPH is poor unless an early diagnosis is made and treatment is initiated. Chest radiography and echocardiography are used in the initial assessment of suspected pulmonary hypertension. A diagnosis of CTEPH may be confirmed by the presence of a mismatched wedge-shaped perfusion deficit during ventilation/perfusion scintigraphy or characteristic findings during multi-slice computed tomography (CT) angiography, including a mosaic perfusion pattern, dilatation of proximal pulmonary arteries and right heart chambers, and the presence of vascular stenosis or obstruction. Prior to possible surgery, pulmonary angiography remains the definitive diagnostic technique, indicating the site and accessibility of the obstruction. However, many centres utilise CT and magnetic resonance imaging following recent advances in these noninvasive techniques. Haemodynamic evaluation via right heart catheterisation is also mandatory, as pulmonary vascular resistance is the most important determinant of both prognosis and the risk associated with pulmonary endarterectomy surgery. Accurate CTEPH diagnosis and characterisation of its extent and distribution are imperative to allow the prompt initiation of treatment, particularly surgical pulmonary endarterectomy in eligible patients.

Figure 1.

Perfusion scintigraphy of a patient with chronic thromboembolic pulmonary hypertension showing multiple wedge-shaped perfusion defects. The ventilation study (not shown) was normal. a) Anterior, b) posterior, c) left posterior oblique and d) right posterior oblique.

Figure 2.

a) Maximal intensity projection from a computed tomography pulmonary arteriogram showing amputation of the basal segment of the right lower lobe and web disease in the left lower lobe in keeping with proximal chronic thromboembolic pulmonary hypertension (CTEPH). Enlargement of the bronchial arteries is also visible. b) Wedge-shaped areas of reduced attenuation in the lung parenchyma indicative of mosaic perfusion consistent with CTEPH.

Figure 3.

Pulmonary angiography in the right lung (a, c, e and g) and the left lung (b, d, f and h) of a patient with chronic thromboembolic pulmonary hypertension. The first image (a–d) was taken at a non-specialist centre with suboptimal vascular opacificaiton and the patient was considered inoperable. The second pulmonary angiography (e–h) was undertaken at a specialist surgical centre with selective angiography showing proximal disease, and resulted in the patient receiving successful pulmonary endarterectomy surgery. a, b, e, f) Anterior view and c, d, g, h) lateral views.

Figure 4.

Magnetic resonance angiography from a patient with chronic thromboembolic pulmonary hypertension a) pre- and b) post-endarterectomy. Unlike other forms of imaging, magnetic resonance angiography does not utilise ionising radiation and is useful for follow-up examinations.