Hellenkamp 2018.

Study characteristics
Patient Sampling	Retrospective
Patient characteristics and setting	Study location: UK and Germany Study periods: between 2011 and 2016 Care setting: the Clinic for Cardiology and Pneumology, University Medical Center Göttingen; King's College Hospital, London; and the Department of Internal Medicine II, University of Regensburg Participants enrolled: 90: 43 males and 47 females Participants included in analysis: 90: 43 males and 47 females Age: mean age 64.8 years (IQR: 55‐79 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: 24 (16%) Number of participants with COPD: not reported Number of intubated participants: 0 Inclusion criteria: patients who underwent echocardiography and right‐heart catheterisation within 24 hours Exclusion criteria: not reported
Index tests	Description of index test: continuous‐wave Doppler ultrasonography of tricuspid regurgitation in apical four‐chamber and parasternal short‐axis views was applied, and the tricuspid regurgitation time‐velocity tracing was determined to obtain the time‐velocity integral, tricuspid regurgitation max velocity, mean tricuspid regurgitation velocity, maximal right atrial–right ventricular gradient, and TRP mean. Description of method to estimate right atrial pressure: Right atrial pressure was estimated by measuring the diameter of the IVC at end expiration and the inspiratory collapsibility in the subcostal view as follows: when the IVC diameter was #21 mm and the collapsibility with a sniff was > 50%, right atrial pressure was estimated to be 3 mmHg; when the IVC diameter was > 21 mm and the collapsibility was < 50%, right atrial pressure was estimated to be 15 mmHg. In all other cases (either IVC diameter > 21 mm and collapse > 50% or IVC diameter #21 mm and collapse < 50%), right atrial pressure was estimated to be 8 mmHg. Cut‐off value to declare PH: 31 mmHg Estimated systolic pulmonary arterial pressure: not reported Sonographer qualification: not reported How to handle the uninterpretable results: not applicable
Target condition and reference standard(s)	Target condition: pulmonary hypertension Description of reference standard: not reported Mean pulmonary arterial pressure: median 35 mmHg (IQR: 24.7‐46.2 mmHg)
Flow and timing	The interval between the index test and reference standard: within 24 hours Number of indeterminates for whom the results of reference standard was available: 0 (0%) Number of patients who were excluded from the analysis: 0 (0%)
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?			Unclear
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?	Unclear
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?	Unclear
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?	Yes
Did all patients receive the same reference standard?	Yes
Were all patients included in the analysis?	Yes
Could the patient flow have introduced bias?		Low risk