Nitric Oxide and Transfusion Therapy for Sickle Cell Patients With Pulmonary Hypertension
Status:
Completed
Trial end date:
2015-11-09
Target enrollment:
Participant gender:
Summary
This study will test whether inhaling nitric oxide (NO) gas mixed with room air can improve
pulmonary hypertension (high blood pressure in the lungs) in patients with sickle cell
anemia.
Patients with sickle cell disease 18 years of age or older may be eligible to participate in
one or more parts of this three-stage study, as follows:
Stage 1
Patients undergo the following tests to determine the cause of their pulmonary hypertension:
blood tests; echocardiogram (heart ultrasound); asthma test; oxygen breathing study with
measurement of arterial blood oxygen levels; chest X-ray; lung scans; MRI of the heart;
6-minute walk test; night-time oxygen measurement while sleeping; and exercise studies.
Stage 2
Patients have a detailed MRI evaluation of the heart and are admitted to the NIH Clinical
Center intensive care unit (ICU) for the following test: A plastic tube is placed in a vein
in the patient's arm and another tube is placed in a deeper neck or leg vein. A third tube is
inserted through the vein into the heart and the lung artery to measure blood pressures in
the heart and lungs directly. Following baseline measurements, three medications (inhaled
oxygen, infused prostaglandin, and inhaled NO) are delivered for 2 hours each, separated by a
30-minute washout period. A small blood sample is drawn during the NO administration.
Patients who cannot be treated with nitric oxide or for whom the treatment does not work may
receive monthly exchange transfusions for 3 months. For this procedure, 3 to 5 five units of
the patient's blood is removed and replaced with 3 to 5 units that do not have sickle
hemoglobin. Some patients who do not respond to NO or exchange transfusions may receive an
alternative therapy, such as oxygen, prostacyclin, L-arginine, bosentan or sidenafil.
Stage 3
Patients remain in the ICU with catheters in place for another 24 hours. During this time
they breathe NO. Lung pressures are measured every 4 hours and blood is drawn every 8 hours.
They then stay in the hospital 1 more day for observation. Patients then breathe nitric oxide
continuously for 2 months using a tank of gas that delivers the NO through tubes placed in
the nose. They may do this at home on an outpatient basis or may remain in the hospital for
the 2 months.
Patients have an echocardiogram and blood tests every week and do a 6-minute walk test every
2 weeks....