Does digoxin have a place in the treatment of the child with congenital heart disease?

Digoxin Associated With Greater Transplant-Free Survival in High- vs Low-Risk Interstage Patients

BACKGROUND

Digoxin has been associated with reduced interstage mortality for patients with functional single ventricles with aortic hypoplasia or ductal-dependent systemic circulation. The NEONATE (type of stage 1 palliation operation, postoperative extracorporeal membrane oxygenation, discharge with opiates, no digoxin at discharge, postoperative arch obstruction, moderate to severe tricuspid regurgitation without an oxygen requirement, and extra oxygen required at discharge in patients with moderate to severe tricuspid regurgitation) score can stratify patients by risk of death or transplantation (DTx) on the basis of clinical factors. The study investigators suspected a variable transplant-free survival benefit of digoxin in high-risk vs low-risk patients.

METHODS

National Pediatric Cardiology Quality Improvement Collaborative patients discharged after stage 1 palliation with complete data were categorized as high- or low-risk on the basis of a modified NEONATE score. The primary outcome of DTx was evaluated. A mixed-effect regression evaluated associations between digoxin prescription and risk factors.

RESULTS

A total of 1199 patients were included; 399 (33%) were high risk. Baseline demographics were similar between the cohorts. Blalock-Taussig shunt or a hybrid operation, postoperative extracorporeal membrane oxygenation, opiate prescription, and significant tricuspid regurgitation or arch obstruction were more common in high-risk patients. The odds of DTx were 65% lower in high-risk patients prescribed digoxin compared with patients who were not (P = .001). Digoxin prescription was associated with 60.8% lower DTx in the high-risk cohort (7.8% vs 19.9%; P = .001). There was no significant difference in the DTx rate according to digoxin prescription in the low-risk cohort (4.7% vs 5.7%; P = .46). Blalock-Taussig shunt, aortic arch obstruction, and significant tricuspid regurgitation were most strongly associated with deriving a benefit from digoxin.

CONCLUSIONS

Digoxin use is associated with significant improvement in transplant-free survival in high-risk but not in low-risk interstage patients. A tailored approach to the use of digoxin in interstage patients may be warranted.

Association of Digoxin With Interstage Mortality: Results From the Pediatric Heart Network Single Ventricle Reconstruction Trial Public Use Dataset

BACKGROUND

Mortality for infants with single ventricle congenital heart disease remains as high as 8% to 12% during the interstage period, the time between discharge after the Norwood procedure and before the stage II palliation. The objective of our study was to determine the association between digoxin use and interstage mortality in these infants.

METHODS AND RESULTS

We conducted a retrospective cohort study using the Pediatric Heart Network Single Ventricle Reconstruction Trial public use dataset, which includes data on infants with single right ventricle congenital heart disease randomized to receive either a Blalock-Taussig shunt or right ventricle-to-pulmonary artery shunt during the Norwood procedure at 15 institutions in North America from 2005 to 2008. Parametric survival models were used to compare the risk of interstage mortality between those discharged to home on digoxin versus those discharged to home not on digoxin, adjusting for center volume, ascending aorta diameter, shunt type, and socioeconomic status. Of the 330 infants eligible for this study, 102 (31%) were discharged home on digoxin. Interstage mortality for those not on digoxin was 12.3%, compared to 2.9% among those on digoxin, with an adjusted hazard ratio of 3.5 (95% CI, 1.1-11.7; P=0.04). The number needed to treat to prevent 1 death was 11 patients. There were no differences in complications between the 2 groups during the interstage period.

CONCLUSIONS

Digoxin use in infants with single ventricle congenital heart disease is associated with significantly reduced interstage mortality.

Evaluation by N-terminal prohormone of brain natriuretic peptide concentrations and ross scoring of the efficacy of digoxin in the treatment of heart failure secondary to congenital heart disease with left-to-right shunts

This study aimed to evaluate the effectiveness of digoxin in children with heart failure secondary to left-to-right shunt lesions and normal left ventricular systolic function. The study registered 37 such patients (ages 10 days to 24 months, groups 1 and 2) and used 20 healthy children as a control group (group 3). Left ventricular systolic function, as assessed by conventional echocardiography, was normal in all the subjects. Congestive heart failure was diagnosed by clinical evaluation and modified Ross scoring. Plasma N-terminal prohormone of brain natriuretic peptide (NT-proBNP) concentrations and complete blood counts were assessed in all the children. Group 1 was treated with digoxin, enalapril, and furosemide and group 2 with enalapril and furosemide. Approximately 1 month after starting treatment, the patients were reevaluated by physical and echocardiographic examinations, modified Ross scoring, plasma NT-proBNP concentrations, and complete blood counts. The pre- and posttreatment Ross scores of group 1 (p = 0.377) and group 2 (p = 0.616) did not differ significantly. The NT-proBNP values in both groups decreased after treatment (p = 0.0001). The pre- and posttreatment NT-proBNP values did not differ significantly in group 1 (p = 0.094)) and group 2 (p = 0.372). The pretreatment NT-proBNP values in groups 1 and 2 (p = 0.0001) were significantly higher than in the control group (p = 0.003). A smaller difference was observed between posttreatment NT-proBNP values in group 1 and the control group (p = 0.045). We found no significant difference between the posttreatment NT-proBNP values of group 2 and those of the control group (p = 0.271). The study showed that both treatments currently used to treat heart failure secondary to congenital heart disease with left-to-right shunts and preserved left ventricular systolic function are effective and do not differ significantly. Thus, digoxin does not provide any extra benefit in the treatment of such patients.

Digitalis use in children: an uncertain future

The therapeutic indications for digoxin in the treatment of children with large left-to-right shunts continue to be reassessed. New insights into the alterations in cardiac function imposed by this hemodynamic burden have shown preserved systolic performance. Pharmacological interventions that improve cardiac output by afterload reduction or other modalities have proven useful and potentially have low risk for serious toxicity. Early and successful surgical treatment of most conditions causing pulmonary overcirculation has shortened the duration of medical management and prevented many of the untoward complications of this pathology. As new agents are forthcoming to treat various cardiac conditions, use-by-tradition of cardiac glycosides has appropriately diminished. While the understanding of complicated molecular aspects of cation transport have been enhanced by the unique actions of cardiac glycosides, their clinical utility has decreased. This report summarizes studies on the use of cardiac glycosides in the treatment of large left-to-right shunts in children.

Further evidence suggesting a limited role of digitalis in infants with circulatory congestion secondary to large ventricular septal defect

In infants with a large ventricular septal defect, the acute hemodynamic effect of intravenous digitalis varies depending on baseline systemic and pulmonary resistance. Digitalis may act adversely by increasing pulmonary blood flow with an elevation in left atrial pressure in severely congested infants with ventricular septal defects.