VentaProst Versus Conventionally-Administered Aerosolized Epoprostenol in Patients Undergoing Cardiac Surgery With CPB

Inclusion Criteria: 1. Women and Men 18 to 75 years of age 2. Provide written informed consent 3. Willing and able to comply with all aspects of the protocol 4. For patients in Part I: 1. Undergo cardiac surgery on CPB 2. Clinically require treatment with and receive aerosolized epoprostenol 3. Demonstrate a clinically meaningful hemodynamic response to aerosolized epoprostenol 5. For patients in Part II: 1. Undergo cardiac surgery with CPB 2. Have perioperative pulmonary hypertension 3. Clinically require treatment with inhaled epoprostenol Exclusion Criteria: 1. Current smoker (i.e., within the last 30 days) 2. Emergency operative status 3. Upper and/or lower respiratory tract infection within four weeks of screening 4. Contraindication to transesophageal echocardiogram (TEE) including esophageal disease or unstable cervical spine 5. Renal or severe hepatic impairment 6. Thromboembolic disease treated with anticoagulant therapy 7. Bleeding disorders 8. Significant restrictive or obstructive lung disease 9. History of concurrent malignancy or recurrence of malignancy within two years prior to Screening 10. History of a diagnosis of drug or alcohol dependency or abuse within approximately the last three years 11. Recent history of stroke or transient ischemic attack 12. Significantly abnormal laboratory tests at Screening 13. Pregnant or breastfeeding 14. Treatment with an investigational drug, biologic, or device within 30 days 15. Other severe, acute, or chronic medical or psychiatric condition or laboratory abnormality that may increase the risk associated with trial participation or investigational product administration or may interfere with the interpretation of trial results and, in the judgment of the Investigator or Sponsor, would make the patient inappropriate for entry into this trial 16. Any condition where aerosolized epoprostenol is contraindicated 17. Known allergy or sensitivity to epoprostenol, any of its ingredients, or the diluent