Sistema de riego de la comunidad “San Rafael de Chuquipogyo” – RED 1

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This study did not establish any significant correlation between NT-proBNP and malnutrition. However, studies which sought to correlate plasma NT-proBNP with nutritional status in paediatric populations with underlying disease conditions which could independently affect NT-proBNP levels such as congenital heart disease, renal failure and HIV found negative correlations suggesting that it may be a marker of myocardial stress.^71,81 Similarly Chazot⁷² et al who examined plasma natriuretic peptide levels in adult patients undergoing haemodialysis for chronic kidney disease found their levels to be significantly negatively correlated with malnutrition. In another study by Fabiensen⁸² and his colleagues in which proANP rather than NT-proBNP was measured in piglets, found markedly elevated proANP levels and cardiac dysfunction in the malnourished group.

The plausible explanation for the finding in the present study may be that the stimulus for natriuretic peptide release is cardiac myocyte stretch and perhaps this stimulus does not occur in PEM where cardiac atrophy with reduced stretch and contractility occurs.⁵¹ In addition, Wunderlich⁸³ et al has suggested that PEM is associated with reduction in synthesis of chorionic mammotropin in rats, a peptide hormone secreted by the placenta in rats, suggesting that protein deficiency is associated with reduced protein synthesis. Findings of insignificant levels of NT-proBNP in this study may also be as a result of inability to initiate synthesis of this hormone in malnourished children.

The preponderance of LV dysfunction in 54.3% of subjects with PEM, which was much higher than the proportion of heart failure diagnosed by the modified Ross score that was only 37.1%, suggests that sub clinical cardiac dysfunction is common in PEM. Similarly Phornphaktul¹⁵ and his colleagues corroborated these findings in

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their subjects who were all severely malnourished, and had no clinical evidence of heart failure, whereas echocardiography demonstrated LV dysfunction in all of them.

Indices of LV systolic dysfunction- ejection fraction and fractional shortening- were significantly decreased in severe PEM in the present study, this finding was corroborated by Singh et al⁸⁴ who in addition measured mean rate of circumferential fibre shortening. This finding can be attributed to the cardiac atrophy and reduced ventricular wall thickness which occurs in severe PEM.

The preponderance of LV diastolic dysfunction observed in 68.4% of subjects with PEM, compared with only 23.7% who had LV systolic dysfunction is in contrast to studies reported by Faddan¹⁶ et al and El-Sayed et al²⁰ who did not find LV diastolic dysfunction in malnourished children. The possible explanation for diastolic dysfunction in malnourished children may be that cardiac atrophy with reduced LV chamber dimension, decreased preload and a resultant impaired ventricular filling occurs in malnutrition.^16,85,86 These changes are mechanisms that lead to diastolic dysfunction; therefore, diastolic dysfunction should not be unusual in PEM. However, it is noteworthy that whereas they measured diastolic dysfunction using only one index, the E/A ratio, the present study applied both E/A and E/E’ ratios as indices of LV diastolic dysfunction. Perhaps the use of two indices may have increased the detection of LV diastolic dysfunction; this will require further studies to corroborate this finding.

Median plasma NT-proBNP were observed to be higher (654.1pg/ml) in subjects with PEM who had LV dysfunction compared with (302.3pg/ml) in those without LV dysfunction, although this was not statistically significant. This finding suggests that NT-proBNP alone may not reliably indicate cardiac dysfunction in PEM patients.

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Also, LV diastolic dysfunction alone and combined LV systolic and diastolic dysfunction, were observed to be associated with higher but not significant levels of NT-proBNP compared with those with LV systolic dysfunction alone. In view of this finding, NT-proBNP alone may not be reliable in identifying cardiac dysfunction, but its utility may be enhanced when used in conjunction with echocardiography.

Correlation between NT-proBNP levels and Ross scores was not significant,( p=

0.937) whereas Lin et al⁸⁷ demonstrated correlation of 95% with modified Ross scores in children with heart failure from varied aetiologies. Ekure et al⁷⁰ also showed a positive correlation of modified Ross scores with NT-proBNP in children with congestive heart failure as a result of congenital heart disease. It is important to note that whereas these two studies had children clinically diagnosed with heart failure as subjects, 62.9% of children with PEM in the present study did not have clinically diagnosed heart failure while only three subjects had severe heart failure.

In comparing laboratory parameters including electrolytes and haemoglobin in children with moderate and severe malnutrition, we found electrolytes and haemoglobin values to be similar in both groups, with only sodium (p= 0.025) being significantly decreased in the severely malnourished group. It is pertinent to note that only five cases of kwashiorkor were recruited in the present study, and this limited number may have accounted for the apparent similarity as electrolyte derangement is known to be more severe in kwashiorkor. This study found a weak correlation between NT-proBNP and sodium levels (p= 0.049) but no correlation with other measured variables including age and gender.

In addition to identifying heart failure and asymptomatic cardiac dysfunction, NT-proBNP has also been useful in prognostication of heart failure.^3,88 It is noteworthy

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that three of the severely malnourished children who died during admission, did not have elevated NT-proBNP levels and were rather within the lower limits of normal.

Additional noteworthy findings in the mortalities were low levels of sodium, potassium and calcium with means of 125.2±26.9, 3.30±2.24 and 1.94±0.34 respectively.