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Participant flowchart. (A) Study sample from FDA clinical trials (derivation sample). (B) Study sample from the Pulmonary Hypertension Association Registry (validation sample). 6MWD = 6-minute-walk distance; CTEPH = chronic thromboembolic pulmonary hypertension; FDA = U.S. Food and Drug Administration; PAH = pulmonary arterial hypertension; SF = Short Form.
