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Prolonged treatment with hydroxyurea may improve -- and possibly even reverse -- cardiac complications in pediatric patients with sickle cell anemia, a retrospective study found.

Those on hydroxyurea for less than 1 year had a significantly greater prevalence of left ventricle (LV) dilation compared with those on the treatment for more than a year, reported Arushi Dhar, MD, of Cohen Children's Heart Center in New Hyde Park, New York, and colleagues.

The mean LV end-diastolic diameter (LVEDd) z-score was 2.24 for kids on hydroxyurea for less than 1 year compared with 1.57 for those taking the treatment for more than a year (P=0.04), while the mean LV end-diastolic volume (LVEDv) z-scores were 2.62 versus 1.72, respectively (P=0.02), the authors noted in .

Moreover, they found that LV dilation and hypertrophy significantly improved with longer hydroxyurea treatment.

Considering that heart abnormalities are a common complication of sickle cell anemia, the study highlights the need for early screening and treatment initiation in this population, said Dhar in a press release. "We need very close cardiac monitoring of children and young adults with sickle cell anemia. Even for asymptomatic individuals, screening should start at a young age so we can catch any abnormalities early and start treatment with hydroxyurea as soon as possible."

Children and adults with sickle cell anemia have been shown to have a higher incidence of pulmonary hypertension, LV hypertrophy, LV dilation, and diastolic dysfunction. Dhar and team aimed to longitudinally examine the incidence of echocardiographic abnormalities in children and young adults with sickle cell anemia, as well as the effectiveness of hydroxyurea in improving these complications or preventing them from progressing.

Their single-center retrospective chart review included 100 patients (mean age 12, 58% male) with sickle cell anemia (HbSS or HbS beta-zero thalassemia genotypes) who underwent routine cardiac screening from 2010 to 2017.

Overall, 50 patients had LV dilation based on LVEDd and/or LVEDv z-score ≥2, while 32% had abnormal tricuspid valve regurgitation velocity of ≥2.5 m/s.

Sixty patients were taking hydroxyurea, 41% of whom had been treated for less than 1 year. There were no differences in LV size, LV mass, and tricuspid valve regurgitation velocity between those on the treatment and those who were not in a comparison of their most recent echocardiograms. Among this group, the age at treatment initiation was positively associated with LV mass (P=0.04) and tricuspid valve regurgitation velocity (P=0.02), noted Dhar and colleagues.

In a treatment effect analysis of 169 serial echocardiograms performed on the 60 kids who were on hydroxyurea (67% male, mean age at the start of treatment 10.3), 72% had an echocardiographic abnormality (abnormal LV size, LV mass, LV systolic function, or elevated tricuspid valve regurgitation velocity) at baseline compared with 38% with an abnormality on their most recent echocardiogram (P=0.01). LV size and mass were the most commonly noted abnormalities.

Patients with LV dilation were more likely to have LV hypertrophy (31 of 38). Of these 38 patients with LV dilation at baseline, 22 (58%) had a normal reading at their most recent visit. "The measures of LV size consistently showed a negative association with the duration of hydroxyurea treatment with the association between LVEDv and duration of treatment being statistically significant (P=0.02)," the authors observed.

Of the 34 patients with abnormal LV mass at baseline, 16 had a normal LV mass measurement at their most recent visit, with the association between LV mass and duration of hydroxyurea treatment statistically significant (P=0.02).

"Despite limitations such as our inability to discern if poor patient medication adherence contributed to the lack of significant difference found in change in certain echocardiographic parameters among patients taking hydroxyurea, our study suggests that the use of sickle cell disease-modifying therapies such as hydroxyurea may limit the progression of, and potentially improve cardiac abnormalities over time, including dilation, hypertrophy and elevated [tricuspid valve regurgitation velocity]," Dhar and colleagues concluded.

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