<qa>  What was the tricuspid regurgitant jet velocity present in 13 of HbSS3. The epidemiology of PH in SCD has been evolving over the past 10-15 years. Numerous studies demonstrated an elevated pulmonary artery systolic pressure PASP by echocardiography reflected by an elevated tricuspid regurgitant jet velocity TRV was present in 13 of HbSS and 10-28 of HbSC adults9-11. However, an elevated TRV only has approximately a 25 positive predictive value for PH in SCD 1. The need for a right heart catheterization to confirm a diagnosis of PH in SCD has only been gaining clinical acceptance over the past few years and when the prior clinical trials were conducted, this was not a standard part of the PH workup in these patients. 