Elevation of tricuspid regurgitant jet velocity, a marker for pulmonary hypertension in children with sickle cell disease

Background. Pulmonary hypertension (PHTN) is a potentially life-threatening complication, detected by echocardiographic evidence of elevated tricuspid regurgitant velocity (TRV). This condition has been described in adults with sickle cell disease (SCD) and other hemolytic disorders; however, there is little information on the occurrence of this condition in pediatric patients. Methods. Records for pediatric SCD patients were retrospectively reviewed to determine clinical characteristics and co-morbidities of patients with elevated TRV on echocardiograms obtained under steady state conditions as an outpatient. Correlation of TRV ≥2.5 m/sec with age, sex, type of SCD, number of outpatient echocardiograms per patient, episodes of vasoocclusive crisis (VOC) and acute chest syndrome (ACS), mean hemoglobin and reticulocyte count, asthma, obstructive sleep apnea, cerebrovascular disease (CVD), and hydroxyurea therapy was determined. Results. Of 224 SCD patients, 44 had outpatient echocardiographic measurement of TRV. Patients (11 of 44) (26.2%) with TRV ≥2.5 m/sec were compared to 31 patients without elevated TRV. Significant differences were noted for percent with HbSS disease (P=0.041), CVD (P=0.021), hemoglobin (P=0.003), % reticulocytes (P=0.037), and number of echocardiograms performed (P<0.001). No significant differences were observed for gender, age, asthma, or frequency of VOC and ACS. Conclusions. Elevated TRV, a surrogate marker for PHTN, occurs in children with SCD and is associated with low hemoglobin, elevated reticulocyte count, and cerebral vasculopathy. Appropriate screening by echocardiography can lead to detection and treatment that may reduce TRV and potentially reverse the disease process, prevent the increased morbidity and mortality associated with PHTN.