Do Pediatric Sickle Cell Disease Patients Develop Diastolic Dysfunction?.

Sickle cell disease (SCD) is a known cause of chronic volume overload. Although systolic dysfunction is rare, as many as 80% of adult patients with SCD have an echocardiographic mitral valve inflow pattern suggestive of abnormal left ventricular (LV) diastolic function (DF). DF has not been studied in pediatric SCD patients. Therefore, the objective of this study was to evaluate DF in pediatric SCD patients using echocardiographic velocities of mitral inflow and tissue Doppler (TDI) indices. Echocardiograms were performed in 79 SCD patients (ages 2 – 18 years), and 84 controls matched for age and race. LV and left atrial (LA) volumes, LV mass, early (E) and late (A) mitral inflow velocities, and TDI velocities at the septal and lateral aspects of the mitral valve were obtained. LV dilatation was defined as LV end-diastolic dimension more then 2 standard deviations above the median (z-value >2). LV hypertrophy was defined as LV mass/volume index>1.15 g/ml. For SCD patients, average hemoglobin (Hb) levels for the year prior to the study were recorded. Data were analyzed using t-test and Spearman correlation analysis.

Of 79 SCD subjects, 32 (43%) had LV dilatation, 11(14.9%) had LV hypertrophy and 3 had both. LV z-scores were inversely related to Hb (r −0.62, p<0.0001) but unrelated to age. The early mitral inflow velocities E were negatively correlated with Hb levels(r − 0.34, p<0.04) and were positively correlated with LV z-scores (r 0.41, p<0.04) reflecting pre-load dependency of mitral inflow indices. DTI diastolic velocities were unrelated to Hg or LV size reflecting pre-load independent nature of these indices. DTI systolic velocities S’ correlated positively with LV mass/volume index (r 0.28, p<0.02).

SCD patients had significantly larger LV and LA volumes than controls (p<0.01). The early E and late A mitral inflow velocities were higher in the SCD group than the control, although the differences were not statistically significant. DTI indices did not differ between SCD patients and the control.

Conclusion: Despite high incidence of left ventricular dilatation, pediatric SCD patients don’t demonstrate diastolic dysfunction when evaluated using pre-load independent echocardiographic tissue Doppler indices.