Tricuspid regurgitant jet velocity elevation and its relationship to lung function in pediatric sickle cell disease

Abstract

Concerns about the morbidity and mortality associated with tricuspid regurgitant jet velocity (TRJV) elevation, which may indicate pulmonary hypertension (PHT), in adults with sickle cell disease (SCD) have prompted growing interest in screening the pediatric sickle cell population. The goals of our study were to estimate the prevalence of TRJV elevation and determine its relationship to pulmonary function in children and young adults with SCD at baseline. Seventy-eight subjects (10-24 years old) with SCD underwent prospective screening by Doppler echocardiogram (ECHO), complete lung function evaluation, and laboratory testing as part of standard care at steady state. Tricuspid regurgitation was quantifiable in 68/78 (87%) subjects and peak TRJV was > or =2.5 m/sec in 26/78 (33.3%) evaluated. The frequency of obstruction, restriction, or abnormal gas exchange found on lung function evaluation was not significantly different in subjects with and without TRJV elevation. However, significant inverse correlations were observed between TRJV and both % predicted forced vital capacity (FVC) (r = -0.29, P = 0.022) and oxygen saturation (r = -0.26, P = 0.036). When compared to subjects without TRJV elevation, subjects with TRJV elevation had significantly lower % predicted forced expiratory volume in 1 sec (FEV(1)) (78.9 +/- 14.4 vs. 86.6 +/- 13.0%, P = 0.023), FVC (82.8 +/- 14.1 vs. 90.7 +/- 12.9%, P = 0.017), and oxygen saturation (95.8 +/- 3.2 vs. 97.5 +/- 2.4%, P = 0.016). We found that the combination of low hemoglobin and low % predicted FVC best predicted TRJV elevation (chi(2) = 17.05, P = 0.001) in our cohort, correctly identifying 70% of cases and resulting in positive and negative predictive values of 60 and 74%, respectively. We conclude that in this young population with SCD, TRJV elevation that is not significantly associated with abnormal lung function is common at baseline.