Chronic thromboembolic pulmonary hypertension: interventional approaches

### Learning objectives Chronic thromboembolic pulmonary hypertension (CTEPH) occurs due to persistent pulmonary obstruction and vasculopathy after an acute pulmonary embolism and is underdiagnosed. Patients experience breathlessness and symptoms and signs of right heart failure and without treatment the prognosis is poor. Available interventional approaches include pulmonary endarterectomy (PEA) and balloon pulmonary angioplasty (BPA), as well as pulmonary hypertension-targeted drug therapy. The choice of treatment depends on anatomical, haemodynamic and patient factors and is determined multidisciplinary team assessment. This review will cover the assessment and treatment of CTEPH with a particular focus on PEA and BPA, as well as highlighting future therapeutic directions. CTEPH is a condition caused by failure of resolution of acute pulmonary embolism (PE) and results in fibrotic tissue deposition and altered vascular remodelling that occludes the pulmonary arteries.1 It has been estimated that between 0.56% and 3% of acute PE develop CTEPH2 resulting in an incidence of 0.9–5.7 cases per million and a prevalence of 8–40 cases per million, although this is likely to be an underestimate as the condition is often under-reported.3 4 Mechanical obstructions and secondary pulmonary vasculopathy cause pulmonary hypertension (PH), right ventricular remodelling and dilatation culminating in breathlessness, a worsening exercise tolerance, presyncope and fatigue that is progressively fatal due to right heart failure.5 ### Diagnosis of CTEPH CTEPH is diagnosed in patients with persistent symptoms of breathlessness, evidence of PH at rest (newly defined as mean pulmonary artery pressure (mPAP) >20 mm Hg (rather than >25 mm Hg) in combination with pulmonary arterial wedge pressure ≤15 mm Hg and pulmonary vascular resistance (PVR) ≥3 Wood units (WU)) and imaging suggestive of thromboembolic pulmonary obstruction following 3 …