3][4] Early diagnosis requires high index of suspicion.3][4] The incidence of CTEPH confirmed by right heart catheterization (RHC) is around 0.5 to 5% after a symptomatic episode of PE, and it is reported more frequent in history of recurrent PE. 4 Diagnostic Evaluation of Chronic Thromboembolic Pulmonary HypertensionThe diagnosis of CTEPH requires at least 3 months of effective anticoagulation, hemodynamic parameters for PH along with evidence of proximal or distal thromboembolic occlusion of the pulmonary vasculature. 5Diagnostic algorithm of CTEPH is shown in ►Fig. 1. Echocardiography is often used as first modality to detect PH for screening symptomatic patients at Keywords ► chronic thromboembolic pulmonary hypertension ► pulmonary embolism ► balloon pulmonary angioplasty ► ventilation perfusion scan ► pulmonary endarterectomy ► right heart catheterization ► pulmonary artery pressure Abstract Chronic thromboembolic pulmonary hypertension is rare, underdiagnosed form of pulmonary hypertension.It is caused by intravascular obstruction of pulmonary arteries due to fibrotic transformation of thromboembolic material and microvasculopathy.It is important to diagnose this variant as potentially curative treatment in the form of pulmonary endarterectomy is available.Last two decades have seen rapid advances in targeted medical management and refinement in balloon pulmonary angioplasty technique, which have provided a viable therapeutic option for patients who deemed to be inoperable.