Comparison of High and Low Doses of Captopril in the Treatment of Neonates with Left-to-Right Shunt

Introduction: Due to the significant differences between the physiology and pathology of adults and neonates, clinical guidelines for adults are not directly applicable to children. This study was performed to evaluate the effects of high- and low- dose captopril on the neonates with large left-to-right shunts. Methods: The study was conducted on 20 neonates with congenital heart disease, left-to-right shunt, and cardiac failure. Based on the Ross scoring system, the neonates were clinically evaluated by measuring renin, aldosterone, and B-type natriuretic peptide, and performing echocardiography. For each neonate, the treatment of heart failure started with digoxin and frusemide, and reevaluation was conducted 3 days after the treatment. Afterwards, the neonates were randomly divided into 2 groups; low- (0.03mg/kg) and high-doses (0.5mg/kg) of captopril were administered, and the reevaluation was carried out, after one week of therapy. Results: The study revealed higher reduction of the Ross score in the high-dose group; however, the change was not statistically significant (P=0.56). B-type natriuretic peptide and aldosterone reduced further in the high-dose group; again the changes were not statistically significant (P=0.4). Moreover, the treatment with captopril increased the pulmonary blood flow (QP), and pulmonary-to-systemic blood flow (QP/QS) in both groups; though the changes were not significant. Conclusion: According to the present study, although high-dose captopril can decrease B-type natriuretic peptide and the neonates clinical symptoms, the resultant changes are not statistically significant. Therefore, clinical decision making should follow a case-by-case basis for each neonate, in order to select the effective dose of captopril.

Keywords:

Angiotensin-converting enzyme inhibitors , congenital heart disease , heart failure , Left-to-right shunt , Neurohormones