Amsallem 2016.

Study characteristics
Patient Sampling	Retrospective
Patient characteristics and setting	Study location: USA Study periods: between 2001 and 2012 Care setting: the Stanford University Advanced Lung Disease centre, Kosuyolu Training Hospital Participants enrolled: 307: 125 males and 182 females Participants included in analysis: 199: gender not reported Age: mean age 50 ± 13 years BMI: not reported Classification of PH defined by WHO (diagnosis from right‐heart catheterisation): not reported Number of patients with asymptomatic or mild symptom: not reported Number of participants with COPD: not reported Number of intubated participants: 0 Inclusion criteria: All participants aged > 18 years referred to the Stanford University Advanced lung disease centre for right‐heart catheterisation and with right‐heart catheterisation and complete echocardiography within 5 days Exclusion criteria: not reported
Index tests	Description of index test: Resting trans‐thoracic echocardiography was performed using the Philips 7500 or iE33 system (Philips Medical Systems, Andover, MA) with 5‐MHz transducers by experienced, credentialed cardiac sonographers. Right ventricular systolic pressure was estimated from the maximal right ventricular–right atrial pressure gradient, using the modified Bernoulli equation 5: right ventricular systolic pressure = 4 (maximal tricuspid regurgitation velocity)2 + right atrial pressure, where maximal tricuspid regurgitation velocity was measured using continuous wave Doppler Description of method to estimate right atrial pressure: Right atrial pressure was estimated in the subcostal view according to the inferior vena cava size and collapsibility following a normal sniff: 3 mmHg if IVC < 15 mm and collapse > 50%, 5 mmHg if IVC between 15 and 21 mm and collapse > 50%, 15 mmHg if IVC > 21 mm and collapse between 10% and 50%, 20 mmHg if IVC > 21 mm and collapse < 10%, and 10 mmHg in all other cases. Cut‐off value to declare PH: 40 mmHg Estimated systolic pulmonary arterial pressure: not reported Sonographer qualification: performed by experienced, credentialed cardiac sonographers How to handle the uninterpretable results: excluded from analysis
Target condition and reference standard(s)	Target condition: pulmonary hypertension Description of reference standard: A balloon catheter was introduced through the right femoral vein or internal jugular vein after local anaesthesia. Patients could be premedicated with 1 to 3 mg of diazepam 30 min before the procedure. Mean pulmonary arterial pressure: mean 36.5 ± 17.8 mmHg
Flow and timing	The interval between the index test and reference standard: within 48 hours Number of indeterminates for whom the results of reference standard was available: 0 (0%) Number of patients who were excluded from the analysis: not stated
Comparative
Notes
Methodological quality
Item	Authors' judgement	Risk of bias	Applicability concerns
DOMAIN 1: Patient Selection
Was a consecutive or random sample of patients enrolled?	Yes
Did the study avoid inappropriate exclusions?	Yes
Could the selection of patients have introduced bias?		Low risk
Are there concerns that the included patients and setting do not match the review question?			High
DOMAIN 2: Index Test (All tests)
Were the index test results interpreted without knowledge of the results of the reference standard?	Yes
If a threshold was used, was it pre‐specified?	Yes
Could the conduct or interpretation of the index test have introduced bias?		Low risk
Are there concerns that the index test, its conduct, or interpretation differ from the review question?			Low concern
DOMAIN 3: Reference Standard
Were the reference standard results interpreted without knowledge of the results of the index tests?	Yes
Were the criteria of reference standard for target condition prespecified?	Yes
Could the reference standard, its conduct, or its interpretation have introduced bias?		Low risk
Are there concerns that the target condition as defined by the reference standard does not match the question?			Low concern
DOMAIN 4: Flow and Timing
Was the interval between the index test and reference standard less than one day?	No
Did all patients receive the same reference standard?	Yes
Were all patients included in the analysis?	No
Could the patient flow have introduced bias?		High risk