Inhaled Nitric Oxide and Inhaled Prostacyclin After Cardiac Surgery for Heart Transplant or LVAD Placement

The study will begin once the participant arrives in the cardiothoracic intensive care unit (CTICU) after heart surgery for either heart transplant or LVAD placement. As is standard of care after these types of surgeries, the participant will arrive in the CTICU with a breathing tube already in place, receiving iNO, and connected to a breathing machine. The participant will be receiving relaxing medication in an intravenous line provided by the cardiac anesthesiologist and the CTICU physicians. The participant will be unaware of the study period while the participant is sedated. Data will be collected from the monitor screen connected to the participant's arterial and venous lines, and if placed, LVAD monitor. These data are:

Central venous pressure (CVP) Mean arterial pressure (MAP) Mean pulmonary artery pressure (MPAP) Cardiac Index (CI) Systemic vascular resistance (SVR) Pulmonary vascular resistance (PVR) Right ventricular stroke work index (RVSWI) LVAD Flow LVAD Pulsatility Index (PI)

These data will be collected at five different time periods during the first eight hours after surgery.

Time zero. Data will be collected after surgery upon your arrival to the CTICU while receiving iNO.
After two hours of iNO treatment data will be collected. iPGI2 will then be combined with the current iNO.
After two hours of combined iNO and iPGI2 treatment, data will be collected. iNO will then be stopped.
After two hours of iPGI2 treatment data will be collected. iNO will be restarted.
After two hours of combined iNO and iPGI2 treatment, data will be collected. The study ends after this data collection time.