Geert Kleinnibbelink

RV Strain-Area Loop following Selexipag 8 173 hepatic impairment, significant left-sided heart disease, severe renal insufficiency, BMI < 18.5 kg/m 2 or had a life expectancy less than 12 months. Inclusion and exclusion criteria were according to phase II and III Selexipag trials. 3, 4 The procedures were performed in accordance with institutional guidelines and conformed to the declaration of Helsinki. The study was approved by the Ethics Research Committee of the Radboud University Medical Center (2018-4036). Participants gave full written and verbal informed consent before participation. In this prospective exploratory study, participants attended the laboratory on two separate occasions. During visit 1, after signing informed consent, baseline echocardiographic assessment, 6-minute walk test (6MWT), functional New York Heart Association (NYHA) classification and a venous blood sampling were performed. After visit 1, the participant was prescribed Selexipag. Clinical PAH nurses (NC, EdG) contacted participants for titration of Selexipag doses weekly. 17 weeks after start with Selexipag, the participant was invited for follow-up measurements (visit 2), during which all measurements were repeated. Echocardiographic assessments, prior to and 17 weeks after start with Selexipag, were performed at rest. All examinations were performed by one highly experienced cardiologist (AvD) using a Vivid E9 ultrasound machine (GE Medical, Horton, Norway), equipped with a 1.5-4.5 MHz transducer. Images were stored in raw digital imaging and communication in medicine (DICOM) format and were exported to an offline workstation (EchoPAC, version 203, GE Medical, Horton, Norway). Data analysis was performed by a single observer with experience in echocardiography (GK). The observer was blinded for the timing (baseline vs. follow-up) under which echocardiography was performed. Cardiac structural and functional measurements were made according to the current guidelines for cardiac chamber quantification. 11 We examined the following structural and functional indices: RV basal and mid-cavity end-diastolic diameters, RV end-diastolic area (RVEDA), RV end-systolic area (RVESA), RV outflow tract (RVOT) diameter at the proximal level in the parasternal long-axis (PLAX) and parasternal short-axis (PSAX) view, right atrial (RA) area, RV fractional area change (RVFAC), tricuspid annular plane systolic excursion (TAPSE), tissue Doppler imaging (TDI) of the tricuspid annulus (RV ‘s, e’, a’), pulmonary artery Doppler acceleration time (PAT) and maximum tricuspid regurgitation velocity (TR Vmax). The pressure gradient between the RV and RA at peak systole (TR maxPG) was estimated