Comparison of chronic thromboembolic pulmonary hypertension (CTEPH) and pulmonary arterial hypertension (PAH)

Common pathophysiological linkMicrovascular arteriopathy resulting in endothelial dysfunction and vascular remodelling
Common symptomsDyspnoea, fatigue, weakness and syncope
AetiologyUnresolved emboli after PEAbnormal proliferation of endothelium and smooth muscle in vessel walls, small vessel thrombi are possible
Unknown aetiology in the absence of previous PE
Risk factorsPrevious PE/VTE and recurrent VTE, infected pacemaker, ventriculoatrial shunt, splenectomy, antiphospholipid antibodies, and lupus anticoagulantGenetic mutation, certain drugs/toxins, HIV, connective tissue disorders, congenital heart disease
Disease phenotypePrimarily affects the elderly of both sexes, episodic course with “honeymoon” periodsTypically affects young women, progressive course
DiagnosisSegmental perfusion defects in V′/Q′ scan, pulmonary angiography, CTNo segmental perfusion defects in V′/Q′ scan, right heart catheterisation
TreatmentPEA surgery for suitable patients, balloon pulmonary angioplasty for segmental/subsegmental disease, medical treatment targeting dysfunctional pathways in endothelial cells of inoperable patientsMedical 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].