Chronic thromboembolic pulmonary hypertension (CTEPH), which has been recognised in the
past in no more than 0.1% patients who had undergone acute pulmonary embolism (APE), is
currently being found in as many as 3–8% of these patients.
The pathophysiology of CTEPH is not fully understood, although the relationship with venous
thromboembolism has a firm basis. The potential causes of the disease include symptomatic
but unrecognised episodes of APE, repetitive episodes of silent pulmonary microemboli and
recurrence of symptomatic APE in the course of initial treatment during and after the cessation
of secondary antithrombotic prophylaxis. The pathomechanisms postulated are failure to
lyse the initial emboli, coagulopathy, thrombosis in situ and peripheral propagation of the
residual emboli. The role of arteriopathy in the initial stage of CTEPH is controversial.
CTEPH should be expected in all patients with chronic exertional dyspnoea and exercise
intolerance in whom other causes can be excluded. The role of medical history, physical
examination, electrocardiography and echocardiography in recognition is under discussion.
Early diagnosis, before the development of pulmonary hypertension, is likely to ensure a good
prognosis in continuously anticoagulated patients. Most patients, however, are diagnosed late
and pulmonary hypertension is already marked. At this stage of CTEPH pulmonary endarterectomy
is the treatment of choice for suitable patients with proximal emboli. Diagnosis of
CTEPH at the stage of decompensated cor pulmonale considerably worsens the prognosis in
solely anticoagulated patients and decreases the benefits of pulmonary endarterectomy