Diagnostic testing to guide the management of chronic thromboembolic pulmonary hypertension: state of the art

Abstract

Chronic thromboembolic pulmonary hypertension (CTEPH) is a life-threatening and debilitating disease affecting up to 5% of survivors of pulmonary embolism. Diagnostic testing is important to distinguish it from other forms of pulmonary hypertension and to assess the feasibility of pulmonary endarterectomy. This review provides an up-to-date perspective on the diagnosis and assessment of the disease. Patients with CTEPH often have a history of pulmonary embolism, deep-vein thrombosis, thrombophilia, splenectomy, ventriculo-atrial shunt, inflammatory bowel disease or malignancy. Chest radiography may reveal pulmonary infarcts. CTEPH is often diagnosed as a wedge-shaped perfusion defect with normal ventilation scan during ventilation-perfusion scintigraphy, but multi-slice computed tomography angiography may be needed for differential diagnosis. Right heart catheterisation is required for diagnostic confirmation. Suitability for surgery is assessed by evaluating the number of obstructed vessels which could be disobliterated in the context of the pulmonary vascular resistance. Pulmonary vascular resistance that is out of proportion to evident obstructions is indicative of distal disease. Conventional pulmonary angiography, multi-slice computed tomography angiography and, potentially, magnetic resonance imaging can aid the decision to operate, but risk stratification systems are needed. In conclusion, CTEPH can be cured surgically, providing that patients are diagnosed and assessed using the appropriate techniques.

FIGURE 1.

Diagnostic imaging algorithm for chronic thromboembolic pulmonary hypertension (CTEPH). CT: computed tomography; MR: magnetic resonance. ^#: pulmonary angiography is usually performed in conjunction with right heart catheterisation and should be performed at centres experienced with CTEPH and pulmonary endarterectomy. Reproduced from [1] with permission from the publisher.

FIGURE 2.

a) Ventilation and b) perfusion scintigraphy of the lungs of a patient with chronic thromboembolic pulmonary hypertension. The dark areas indicate regions of the lung with good ventilation or perfusion, respectively.

FIGURE 3.

a) Conventional angiography and b) magnetic resonance angiography of the lungs of a patient with chronic thromboembolic pulmonary hypertension, showing webs and occlusions.

FIGURE 4.

Multi-scan computed tomography showing mosaic perfusion in the lungs of a patient with chronic thromboembolic pulmonary hypertension. The darker areas indicate regions of poor perfusion.