Hydroxyurea for Children and Young Adults With Sickle Cell Disease and Pulmonary Hypertension

Increasing evidence suggests that pulmonary hypertension, defined by an elevated tricuspid regurgitant jet velocity (TRJV) on echocardiogram, is a major cause of morbidity and mortality in adults with sickle cell disease (SCD). However, both the prevalence and optimal treatment of pulmonary hypertension in children and young adults with SCD are unknown.

We hypothesize that short term therapy with hydroxyurea will decrease TRJV in children and young adults with pulmonary hypertension found on screening. Patients eligible for treatment will have had evidence of pulmonary hypertension on at least 2 screening echocardiograms. Baseline laboratory tests will be obtained and other causes of secondary pulmonary hypertension will be excluded prior to initiation of treatment. Patients will be treated with hydroxyurea according to a standard dose escalation schedule for a total of 12 months. A clinic visit will be required every 2 months and standard screening for toxicity will be performed monthly. There will be an interim analysis of the primary outcome at 6 months following therapy.

Inclusion criteria

• Age between 10 and 25 years old
• Sickle cell disease with hemoglobin SS, SC or S-B^0 thalassemia confirmed on hemoglobin electrophoresis
• Tricuspid regurgitant jet velocity (TRJV) equal to or greater than 2.5 m/sec on 2 baseline Doppler echocardiograms at least 3 months apart

Exclusion criteria

• Patients already being treated with hydroxyurea
• Patients on a chronic transfusion protocol
• Patients with evidence of hepatic (alanine aminotransferase [ALT] equal to or greater than 2 SD above normal) or renal dysfunction (creatinine [Cr] equal to or greater than 2 SD above normal)
• Patients who are pregnant
• Patients with documented causes of severe pulmonary hypertension other than from SCD