The importance of echocardiography as a screening method in cases of clinical suspicion of PAH is undisputed. However, it is not possible to use it to distinguish between pre- and post-capillary pulmonary hypertension. A further limitation is the fact that the pressure in the small circulation system estimated using echocardiography is under- or overestimated by over 20% in more than 50% of cases. If the systolic pulmonary pressure estimated with echocardiography is between 37 and 50 mmHg, PAH is a possibility and the European guidelines currently in force provide for a Class IIa indication for carrying out right heart catheterisation (RHC). If the systolic pulmonary pressure in the echocardiogram is more than 50 mmHg, PAH is likely and RHC should always be performed (Class I indication).
Parameters for assessment of the pulmonary circulation are: systolic pulmonary arterial pressure, right heart dimensions, right ventricular function, right ventricular mass and tricuspid regurgitation. Prognostic parameters that can be ascertained using echocardiography are pericardial effusion, the size of the right atrium and the size ratio between right and left end-diastolic diameter. TAPSE (Tricuspid Annular Plane Systolic Excursion) can also be used to draw conclusions about mean survival. A TAPSE <1.8cm is linked to greater right ventricular systolic dysfunction. In addition, TTE allows the diagnosis of a potential underlying cause (e.g. shunt defect, valvular or myocardial disease).