Left ventricle myocardial performance in Down Syndrome children with clinically and anatomically normal hearts: Relationship to oxidative stress

Abstract

Oxidative stress is implicated in many organs pathophysiologies in Down syndrome. Scarce data exist concerning left ventricular (LV) performance in DS children with normal hearts. Tissue Doppler derived myocardial performance index (TDI-Tei index) is a reliable method for ventricular performance evaluation. Myeloperoxidase (MPO) enzyme plays a crucial role in oxidants production and is a marker of cardiovascular risk.

Aim: To evaluate LV myocardial performance in DS children with normal hearts using TDI-Tei index and correlate it with plasma MPO as a marker of oxidative stress.

Patients and methods: This cross-sectional study included 120 DS children recruited from Children s Hospital, Ain Shams University. Out patients clinic and echocardiography unit (mean age, 8.35 ± 4.25 years) who were subjected to: history taking, clinical examination, laboratory investigations (Complete blood count, serum Alanine Transaminase, serum creatinine, Thyroid profile, 12 lead Electrocardiogram and conventional Doppler echocardiography). DS children with congenital or acquired heart diseases, dysrhythmias, anaemia, pulmonary hypertension, thyroid, renal disease, diabetes were excluded. The remaining 50 DS children with normal hearts (group I) were compared to 50 age. Sex matched healthy children as control (group II) Studied groups were subjected to: plasma MPO using ELISA technique and TDI LV-Tei index assessment using Vivid E9 Echocardiography machine (GE, Horton, Norway).

Results: LV TDI-Tei was significantly increased in group I compared to group II (0.46 ± 0.02 vs 0.32 ± 0.08, p < 0.001). Plasma MPO was increased in group I than group II (64.4831 ± 0.6 ng/ml vs 50.4 ± 30.2 nglml, p < 0.001). A significant positive correlation was found between plasma MPO and LV TDI-Tei (r = 0.877, p = 0.001) in group I.

Conclusion: Subclinical Left ventricle dysfunction evidenced by increased TDI Tei index was detected in DS children with normal hearts. This dysfunction correlated with plasma MPO level which mandates antioxidants treatment and tissue Doppler myocardial performance regular evaluation for early identification, monitoring and early intervention.

Keywords: Left ventricle, Tissue doppler, Tei index, Oxidants, DS with normal hearts