Chlorhexidine Mouthwash and Oral Nitrate in Adults With Pulmonary Hypertension

This is an open-label, single-center study to examine distinguishing features of the structure and function of the oral and gut microbiome in volunteers with PH in the breakdown of oral nitrate and effect on hemodynamics. The investigators will enroll 40 PH patients over three years. 5 healthy participants will be enrolled as controls. Participants will receive a single dose of the study drug,:14N Sodium Nitrate(1000mg): standard sodium nitrate, and all will receive one dose of CLA 3g. CLA will be obtained from GNC (General Nutrition Corporation) and given once. Participants will be randomized to receive chlorhexidine gluconate 0.12% (15mL) or placebo to rinse their mouth with for 1 minute. Oral samples will be collected pre- and post-chlorhexidine treatments and stool samples will be collected post-chlorhexidine treatment. Right heart catheterization will be performed for clinical or research purposes. The RHC done (in the last 5 years) that establishes inclusion is not the same RHC done as part of the study in most cases. If there is a strong suspicion of PH based on echocardiography in a patient who has not had a clinical RHC, the first hemodynamic measurements obtained in the clinical RHC will establish inclusion and the RHC study procedures will be performed following confirmation of inclusion. Participants for whom the RHC done in the study is considered a clinical RHC will be participants who do have an additional follow up RHC scheduled. Participants for whom the RHC done in the study is considered a research RHC will be those who do not have an additional follow RHC scheduled or who are considered healthy and have not had an RHC before. Catheterization will generally be performed via the right internal jugular vein access with the assistance of fluoroscopy, if needed. Once the pulmonary arterial (PA) catheter has been placed in proper position, measured values will be obtained. The investigators often perform simultaneous measurement of right atrial pressure and distal pressure (PAP/PAWP) using two transducers in order to assess both pressures during vasodilator challenge, or other confrontational testing. An initial hemodynamic profile will be obtained. With the right heart catheter still in place, participants will be randomized to either chlorhexidine mouthwash or placebo, then after 30 minutes, all will receive 14N oral nitrate and CLA. A repeat hemodynamic profile will be performed after two hours. Nitrate metabolites in plasma will be measured at time 0, 2, and 6 hrs after 14N nitrate dose. Urine nitrite and nitrate will be measured at 0 and 6 hours. Participants will be monitored with continuous pulse oximetry and EKG monitoring. Blood pressure measurements will be performed every 15 minutes during the catheterization. Pressure-volume loop and impedance analysis will be performed at the time of the right heart catheterization (RHC) using the micromanometer catheter technique to simultaneously measure RV pressure and pulmonary blood flow.