**9. Conclusion**

We believe that over the past decade, a paradigm shift has occurred in CTEPH. The disease is much more common than anticipated and it is imperative that patients with this condition be adequately diagnosed to have access to surgery and well designed clinical trials. Although CTEPH is one of the leading causes of severe PH, it remains underdiagnosed. These delays in diagnosis contribute to the poor prognosis associated with the disease. Diagnosis of CTEPH requires input from various imaging techniques. Echocardiography, V/Q scintigraphy and possibly CT angiography are all essential in the initial diagnosis of CTEPH. Pulmonary angiography remains the gold standard diagnostic technique for assessing operability but recent advances in CT and MRI angiography show great promise. Furthermore, haemody‐ namic evaluation by right heart catheterisation provides vital prognostic information and an estimate of the relative risk of PEA surgery. CTEPH should be considered in all patients with PH as early diagnosis helps to identify those patients suitable for PEA, a potentially curative treatment. All patients with suspected CTEPH should be referred to an expert centre for a proper diagnostic evaluation to exclude or confirm the diagnosis and assess operability.
