Anne-Marie Koop

180 SUPPLEMENTAL MATERIAL Pulmonary artery banding Pulmonary artery banding was performed with a 19-gauge needle by approaching through left thoracotomy, as described previously 6 . Sham surgery was identical to PAB surgery with exception of the banding itself. Surgery took place under anaesthesia (isoflurane/air mixture, 5% induction; 2–3% maintenance; analgesia with buprenorphine 0.01mg/kg s.c.) and ventilation through intubation. Echocardiography Echocardiography was performed at 2, 5 and 12 weeks in all animals according to previous described protocol using a Vivid Dimension 7 and 10S-transducer (GE Healthcare, Waukesha, WI, USA.). 5 Rats were anesthetized with isoflurane (induction 5%; 2-3% maintenance) and warmed at 37°C. Parasternal long axis (PLAX), short axis (at aortic and midpapillary level), apical four chamber and 5 chamber view were derived to measure PAB-gradient, LV cardiac output (LV CO), stroke volume (SV) eccentricity index end diastolic (EI ED), eccentricity index end systolic (EI ES), and tricuspid annular plan systolic excursion (TAPSE). Cardiac output was calculated by systolic aortic diameter ² ∙ 3.14 ∙ velocity time integral x heart rate. Heart rate was determined over ten heart beats. Heart catheterization Invasive pressure measurements were performed in anesthetized and intubated rats at 2, 5 or 12 weeks, using a pressure-admittance catheter (1.9F, 6mm spacing) (Transonic, Ithaca, NY, USA), where after termination took place. The catheter was warmed at 37°C and, after bilateral thoracotomy and percarditomy, introduced in the RV at the apex towards the outflow tract. Pressure, phase and magnitude were recorded by ADVantage PV System (ADV500) processor (Transonic, Ithaca, NY, USA) with Chartlab 5. Analyses were performed with custom made software (Circlab 2012, P. Steendijk). In this study we selectively used volume independent derived parameters. Derived from RV peak pressure (RV peak P) mean pulmonary artery pressure (mPAP) was calculated (RV peak P/1.61) and used to determine the RV workload (mPAP ∙ SV) and power (mPAP ∙ CO). Both maximum and minimum delta pressure/delta time (RV dP/dt max respectively RV dP/dt min ) were corrected for RV peak P.