[Decreased Heart Rate Variability in Sickle Cell Anemia as Effect of Pulmonary Arterial Hypertension]

Decreased heart rate variability (HRV) is associated with increased mortality risk in various diseases. The objective of this investigation:to study HRV in patients with sickle cell anemia (SCA) and to assess the effect of pulmonary arterial hypertension (PAH) on HRV in these patients. Materials and methods. HRV registration and Doppler echocardiographic assessment of systolic pulmonary arterial pressure (PAP) was carried out in 61 stable patients with SCA and 24 healthy subjects. Results. Low frequency power (LFP) and high frequency power (HFP) were decreased in SCA patients compared to healthy subjects. Among SCA patients, PAH patients had lower  LFP and HFP than patients without PAH. In SCA patients, systolic PAP showed significant negative correlation with LFP and HFP. Conclusion. HRV is significantly decreased in SCA patients, especially in those with PAH. HRV may be particularly useful in early detection of PAH patients who may have worse prognosis and higher mortality risk.

Renal function in children with sickle cell anemia

BACKGROUND

Patients with sickle cell anemia have various forms of renal dysfunction.

SUBJECTS, MATERIALS AND METHODS

The purpose of this study is to demonstrate the abnormalities of HbSS patients' renal function in childhood. Renal function studies were performed in 55 patients with homozygote sickle cell anemia and compared with 13 healthy children. The blood and timed urine samples were obtained for hematological and biochemical determinations.

RESULTS

Mean serum creatinine, sodium, phosphorus and calcium levels were not statistically different between patients and controls. Mean serum potassium and uric acid levels were significantly higher in patients than in controls. Mean tubular phosphate reabsorption (p < 0.001) and fractional excretion of potassium (p < 0.05) were lower in patients than in the control. There were no significant differences in fractional excretion of sodium and uric acid between patients and controls. Patients had significantly higher urine pH and significantly lower specific gravity and osmolality than controls. Also, there were no significant differences in urinary protein/ creatinine, urinary N-acetyl-beta-D-glucosaminidase/creatinine and urinary malondialdehyde/creatinine between patients and controls.

CONCLUSION

Thus, significant proximal tubular dysfunction is not a common feature but distal tubular abnormality is the most consistent renal functional derangement of patients with SCA in childhood.

Renal function in pediatric patients with beta-thalassemia major

In patients with beta-thalassemia major, the most important cause of mortality and morbidity is organ failure due to deposits of iron. In this study, the nature of the kidney injury and possible pathogenetic factors were investigated. Seventy children with beta-thalassemia major and 14 age and sex-matched healthy children were involved in the study. Blood and timed urine samples were obtained for hematological and biochemical tests. The mean values of blood urea nitrogen (BUN), serum creatinine, creatinine clearance, serum sodium, urine osmolality, fractional excretion of sodium, potassium, and uric acid were not statistically different between the groups. Serum levels of potassium, phosphorus, and uric acid and the urine volume, high urinary protein to creatinine (UP/Cr), urinary N-acetyl-beta-D-glucosaminidase to creatinine (UNAG/Cr), and urinary malondialdehyde to creatinine, (UMDA/Cr) and the tubular phosphate reabsorption (TRP) values were statistically different between two groups (P<0.05). Increased serum levels of potassium, phosphorus, and uric acid in the patient group were attributed to the rapid erythrocyte turnover. The presence of high UP/cr, UNAG/Cr and UMDA/Cr ratios shows that in these patients with proximal renal tubular damage may be secondary to oxidative lipid peroxidation mediated by the iron overload.