Comparison of chronic thromboembolic pulmonary hypertension (CTEPH) and pulmonary arterial hypertension (PAH)
| CTEPH | PAH | |
| Common pathophysiological link | Microvascular arteriopathy resulting in endothelial dysfunction and vascular remodelling | |
| Common symptoms | Dyspnoea, fatigue, weakness and syncope | |
| Aetiology | Unresolved emboli after PE | Abnormal proliferation of endothelium and smooth muscle in vessel walls, small vessel thrombi are possible |
| Unknown aetiology in the absence of previous PE | ||
| Risk factors | Previous PE/VTE and recurrent VTE, infected pacemaker, ventriculoatrial shunt, splenectomy, antiphospholipid antibodies, and lupus anticoagulant | Genetic mutation, certain drugs/toxins, HIV, connective tissue disorders, congenital heart disease |
| Disease phenotype | Primarily affects the elderly of both sexes, episodic course with “honeymoon” periods | Typically affects young women, progressive course |
| Diagnosis | Segmental perfusion defects in V′/Q′ scan, pulmonary angiography, CT | No segmental perfusion defects in V′/Q′ scan, right heart catheterisation |
| Treatment | PEA surgery for suitable patients, balloon pulmonary angioplasty for segmental/subsegmental disease, medical treatment targeting dysfunctional pathways in endothelial cells of inoperable patients | Medical treatment targeting dysfunctional pathways in endothelial cells |
PE: pulmonary embolism; VTE: venous thromboembolism; V′/Q′: ventilation/perfusion; CT: computed tomography; PEA: pulmonary endarterectomy. Information from [8].