Studies of adult patients (more than 18 years) in whom right ventricular systolic pressure (RVSP) was measured by Doppler transthoracic echocardiography and calculated from the maximum tricuspid regurgitation jet velocity by using the modified Bernoulli equation (4v²) and adding right atrial pressure (RAP) were eligible for inclusion. RAP had to be estimated from jugular venous pressure (JVP), given a fixed value from 5mmHg to 10mmHg or estimated by measuring the inferior vena cava size and change with spontaneous respiration using echocardiography. Included studies had to measure systolic pulmonary arterial pressure (sPAP) by right heart catheterisation (reference standard) and perform echocardiography within three months of the right heart catheterisation.
Studies had to report data on the correlation between RVSP measured by echocardiography and sPAP measured by right heart catheterisation or sufficient data to populate 2x2 contingency tables (numbers of true positive, false negative, false positive and true negative test results).
Most of the included studies were published between 2000 and 2009, were performed in USA and were prospective in design. Mean age of study populations was 58 years. Mean percentage of male participants was 58%. Study populations varied and included participants with cardiac disease (various causes), lung disease (various causes), or mixed cardiac and lung disease.
Studies were independently assessed for inclusion by two reviewers. Disagreements were resolved by consensus or consultation with a third reviewer.