Diagnostic Algorithm for Pulmonary Arterial Hypertension (PAH)

Initial Evaluation for Suspected PAH

The American Thoracic Society recommends performing ECG to screen for cardiac abnormalities and arrhythmias, recognizing it has limited sensitivity but provides prognostic information 1
The American College of Chest Physicians suggests obtaining chest radiograph (CXR) to identify features supportive of PAH diagnosis and potential underlying diseases 1
The European Society of Cardiology recommends conducting Doppler echocardiography as the primary non-invasive screening test to detect elevated pulmonary arterial pressure 1, 3
The American Heart Association recommends evaluating right ventricular systolic pressure and assessing for associated abnormalities including right atrial enlargement, right ventricular enlargement, and pericardial effusion 2

The American College of Rheumatology recommends testing for connective tissue diseases and HIV infection in patients with unexplained PAH 1, 4
The European Respiratory Society suggests performing ventilation-perfusion (V/Q) scanning to rule out chronic thromboembolic pulmonary hypertension (CTEPH); a normal scan effectively excludes CTEPH 2, 4

The American College of Cardiology recommends performing right heart catheterization in all patients with suspected PAH to confirm the diagnosis of PAH, establish the specific diagnosis, determine disease severity, and guide therapy 1, 2, 4, 6
The European Society of Cardiology defines positive acute response as a decrease in mean pulmonary arterial pressure of at least 10 mmHg to ≤40 mmHg with unchanged or increased cardiac output 4

The World Health Organization determines functional class and exercise capacity using the 6-minute walk test to establish disease severity, response to therapy, and progression 2
The European Respiratory Society monitors parameters that predict worse prognosis, including clinical evidence of right ventricular failure, rapid progression of symptoms, presence of syncope, WHO functional class III-IV, short 6-minute walk distance (<300m), elevated BNP/NT-proBNP levels, presence of pericardial effusion on echocardiography, and elevated right atrial pressure or reduced cardiac index 3, 5, 6

The European Respiratory Society recommends performing serial assessments at baseline, every 3-6 months, with initiation or changes in therapy, and in case of clinical worsening 6
The American Thoracic Society includes clinical assessment, WHO functional class determination, ECG, 6-minute walk test, BNP/NT-proBNP measurement, and echocardiography in follow-up evaluations 6

The American College of Chest Physicians recommends avoiding lung biopsy for PAH diagnosis due to significant risks unless specific questions can only be answered by tissue examination 2
The European Society of Cardiology recognizes that Doppler echocardiography may be imprecise in determining actual pressures compared to invasive evaluation 1, 3