EDNRB and pulmonary arterial hypertension: To test this hypothesis, we recruited 89 patients (age: 59.0 ± 1.2 years) undergoing unilateral total knee arthroplasty (75 patients) or fracture repair of lower legs (14 patients) under general anesthesia at the Affiliated Hospital of Xuzhou Medical University between September 2017 and March 2019 and treated them with either a placebo or bosentan, a mixed ETAR/ETBR antagonist, which is an available treatment for PAH (Figure7a,b).