A prospective appraisal of pulmonary hypertension in children with sickle cell disease

Pulmonary hypertension (PHT) is a life-threatening complication of sickle cell disease that occurs in 20% to 40% of adults. Measurement of maximal tricuspid regurgitant jet velocity (TRV) by echocardiography provides a noninvasive screening tool; TRV values > or =2.5 m/s are correlated with PHT and increased mortality. Our objective was to estimate the prevalence of PHT in our pediatric sickle cell population and its possible association with various clinical and laboratory findings, including obstructive sleep apnea and/or pulmonary dysfunction. Eligible children had measurement of the TRV. Clinical data were collected, including detailed history with a standardized sleep apnea questionnaire; those with suggestive histories had polysomonography. Pulmonary function was assessed using whole body plethysmography. Of 48 subjects (79% homozygous sickle cell anemia; median age 12 y; 11 receiving chronic transfusion) enrolled in the study, 4 (8.3%) had TRV >2.5 m/s; all had homozygous sickle cell anemia and 1 was receiving hydroxyurea after 3 years of transfusion for secondary stroke prevention. Subjects with elevated TRV had higher indirect bilirubin levels; we found no association between elevated TRV and obstructive apnea or pulmonary function abnormalities. Elevation of TRV was relatively uncommon in our pediatric patients as compared with prevalence reported in adults and may be associated with increased hemolysis. There was no association with obstructive sleep apnea or abnormal pulmonary function.