Trends in Discharge Prescription of Digoxin After Norwood Operation: An Analysis of Data from the Pediatric Health Information System (PHIS) Database

Effect of patient factors, center, and era on Fontan timing: An observational study using the Pediatric Health Information Systems Database

BACKGROUND

There are no consensus guidelines defining optimal timing for the Fontan operation, the last planned surgery in staged palliation for single-ventricle heart disease.

OBJECTIVES

Identify patient-level characteristics, center-level variation, and secular trends driving Fontan timing.

METHODS

A retrospective observational study of subjects who underwent Fontan from 2007 to 2021 at centers in the Pediatric Health Information Systems database was performed using linear mixed-effects modeling in which age at Fontan was regressed on patient characteristics and date of operation with center as random effect.

RESULTS

We included 10,305 subjects (40.4% female, 44% non-white) at 47 centers. Median age at Fontan was 3.4 years (IQR 2.6-4.4). Hypoplastic left heart syndrome (-4.4 months, 95%CI -5.5 to -3.3) and concomitant conditions (-2.6 months, 95%CI -4.1 to -1.1) were associated with younger age at Fontan. Subjects with technology-dependence (+4.6 months, 95%CI 3.1-6.1) were older at Fontan. Black (+4.1 months, 95%CI 2.5-5.7) and Asian (+8.3 months, 95%CI 5.4-11.2) race were associated with older age at Fontan. There was significant variation in Fontan timing between centers. Center accounted for 10% of variation (ICC 0.10, 95%CI 0.07-0.14). Center surgical volume was not associated with Fontan timing (P = .21). Operation year was associated with age at Fontan, with a 3.1 month increase in age for every 5 years (+0.61 months, 95%CI 0.48-0.75).

CONCLUSIONS

After adjusting for patient-level characteristics there remains significant inter-center variation in Fontan timing. Age at Fontan has increased. Future studies addressing optimal Fontan timing are warranted.

Trends in Ductus Arteriosus Stent Versus Blalock-Taussig-Thomas Shunt Use and Comparison of Cost, Length of Stay, and Short-Term Outcomes in Neonates With Ductal-Dependent Pulmonary Blood Flow: An Observational Study Using the Pediatric Health Information Systems Database

BACKGROUND

The modified Blalock-Taussig-Thomas shunt is the gold standard palliation for securing pulmonary blood flow in infants with ductal-dependent pulmonary blood flow. Recently, the ductus arteriosus stent (DAS) has become a viable alternative.

METHODS AND RESULTS

This was a retrospective multicenter study of neonates ≤30 days undergoing DAS or Blalock-Taussig-Thomas shunt placement between January 1, 2017 and December 31, 2020 at hospitals reporting to the Pediatric Health Information Systems database. We performed generalized linear mixed-effects modeling to evaluate trends in intervention and intercenter variation, propensity score adjustment and inverse probability weighting with linear mixed-effects modeling to analyze length of stay and cost of hospitalization, and generalized linear mixed modeling to analyze differences in 30-day outcomes. There were 1874 subjects (58% male, 61% White) from 45 centers (29% DAS). Odds of DAS increased with time (odds ratio [OR] 1.23, annually, P<0.01 [95% CI, 1.10-1.38]) with significant intercenter variation (median OR, 3.81 [95% CI, 2.74-5.91]). DAS was associated with shorter hospital length of stay (ratio of geometric means, 0.76 [95% CI, 0.63-0.91]), shorter intensive care unit length of stay (ratio of geometric means, 0.77 [95% CI, 0.61-0.97]), and less expensive hospitalization (ratio of geometric means, 0.70 [95% CI, 0.56-0.87]). Intervention was not significantly associated with odds of 30-day transplant-free survival (OR,1.18 [95% CI, 0.70-1.99]) or freedom from catheter reintervention (OR, 1.02 [95% CI, 0.65-1.58]), but DAS was associated with 30-day freedom from composite adverse outcome (OR, 1.51 [95% CI, 1.11-2.05]).

CONCLUSIONS

Use of DAS is increasing, but there is variability across centers. Though odds of transplant-free survival and reintervention were not significantly different after DAS, and DAS was associated with shorter length of stay and lower in-hospital costs.

The NEONATE score predicts freedom from interstage mortality or transplant in a modern cohort

BACKGROUND

Derived from the National Pediatric Cardiology Quality Improvement Collaborative registry, the NEONATE risk score predicted freedom from interstage mortality or heart transplant for patients with single ventricle CHD and aortic arch hypoplasia discharged home following Stage 1 palliation.

OBJECTIVES

We sought to validate the score in an external, modern cohort.

METHODS

This was a retrospective cohort analysis of single ventricle CHD and aortic arch hypoplasia patients enrolled in the National Pediatric Cardiology Quality Improvement Collaborative Phase II registry from 2016 to 2020, who were discharged home after Stage 1 palliation. Points were allocated per the NEONATE score (Norwood type-Norwood/Blalock-Taussig shunt: 3, Hybrid: 12; extracorporeal membrane oxygenation post-op: 9, Opiates at discharge: 6, No Digoxin at discharge: 9, Arch Obstruction on discharge echo: 9, Tricuspid regurgitation ≥ moderate on discharge echo: 12; Extra oxygen plus ≥ moderate tricuspid regurgitation: 28). The composite primary endpoint was interstage mortality or heart transplant.

RESULTS

In total, 1026 patients met inclusion criteria; 61 (6%) met the primary outcome. Interstage mortality occurred in 44 (4.3%) patients at a median of 129 (IQR 62,195) days, and 17 (1.7%) were referred for heart transplant at a 167 (114,199) days of life. The median NEONATE score was 0(0,9) in those who survived to Stage 2 palliation compared to 9(0,15) in those who experienced interstage mortality or heart transplant (p < 0.001). Applying a NEONATE score cut-off of 17 points that separated patients into low- and high-risk groups in the learning cohort provided 91% specificity, negative predictive value of 95%, and overall accuracy of 87% (85.4-89.5%).

CONCLUSION

In a modern cohort of patients with single ventricle CHD and aortic arch hypoplasia, the NEONATE score remains useful at discharge post-Stage 1 palliation to predict freedom from interstage mortality or heart transplant.

Association of Digoxin Use With Transplant-Free Interstage Survival in Infants Palliated With a Stage 1 Hybrid Procedure

Background Digoxin prescription in patients with single-ventricle physiology after stage 1 palliation is associated with reduced interstage death. Prior literature has primarily included patients having undergone the Norwood procedure. We sought to determine if digoxin prescription at discharge in infants following hybrid stage 1 palliation was associated with improved transplant-free interstage survival. Methods and Results A retrospective multicenter cohort analysis was conducted using data from the National Pediatric Cardiology Quality Improvement Collaborative registry data from 2008 to 2021. Infants with functional single ventricles and aortic arch obstruction discharged home after the hybrid stage 1 palliation hospitalization were included. Patients were excluded if they had supraventricular tachycardia or conversion to Norwood operation. The primary outcome was transplant-free survival. Multivariable logistic regression analysis including a propensity score for digoxin use identified associations between digoxin use and interstage death or transplant. Of 259 included infants from 45 sites, 158 (61%) had hypoplastic left heart syndrome. Forty-nine percent had a gestational age ≤38 weeks, 18% had a birth weight <2.5 kg, and 58% had a preoperative risk factor. Of the 259 subjects, 129 (50%) were discharged on digoxin. Interstage death or transplant occurred in 30 (23%) patients in the no-digoxin group compared with 18 (14%) in the digoxin group (P=0.06). With multivariate analysis, discharge digoxin prescription was associated with a lower risk of interstage death or transplant (adjusted odds ratio, 0.48 [95% CI, 0.24-0.93]; P=0.03). Conclusions In infants with single-ventricle physiology who underwent hybrid stage 1 palliation, digoxin prescription at hospital discharge was associated with improved interstage transplant-free survival.

Attributable mortality benefit of digoxin treatment in hypoplastic left heart syndrome after the Norwood operation: An instrumental variable-based analysis using data from the Pediatric Health Information Systems Database

BACKGROUND

Observational studies have demonstrated an association between the use of digoxin and reduced interstage mortality after Norwood operation for hypoplastic left heart syndrome (HLHS). Digoxin use has increased significantly but remains variable between different hospitals, independent of case-mix. Instrumental variable analyses have the potential to overcome unmeasured confounding, the major limitation of previous observational studies and to generate an estimate of the attributable benefit of treatment with digoxin.

METHODS

A cohort of neonates with HLHS born from January 1, 2007 to December 31, 2021 who underwent Norwood operation at Pediatric Health Information Systems Database hospitals and survived >14 days after operation were studied. Using hospital-specific, 6-month likelihood of administering digoxin as an instrumental variable, analyses adjusting for both unmeasured confounding (using the instrumental variable) and measured confounders with multivariable logistic regression were performed.

RESULTS

The study population included 5,148 subjects treated at 47 hospitals of which 63% were male and 46% non-Hispanic white. Of these, 44% (n = 2,184) were prescribed digoxin. Treatment with digoxin was associated with superior 1-year transplant-free survival in unadjusted analyses (85% vs 82%, P = .02). This survival benefit persisted in an instrumental-variable analysis (OR: 0.71, 95% CI: 0.54-0.94, P = .01), which can be converted to an absolute risk reduction of 5% (number needed to treat of 20).

CONCLUSIONS

In this observational study of patients with HLHS after Norwood using instrumental variable techniques, a significant benefit in 1-year transplant-free survival attributable to digoxin was demonstrated. In the absence of clinical trial data, this should encourage the use of digoxin in this vulnerable population.

Impact of Device Miniaturization on Insertable Cardiac Monitor Use in the Pediatric Population: An Analysis of the MarketScan Commercial and Medicaid Databases

Background

Insertable cardiac monitors (ICMs) are effective in the detection of paroxysmal arrhythmias. In 2014, the first miniaturized ICM was introduced with a less invasive implant technique. The impact of this technology on ICM use in pediatric patients has not been evaluated. We hypothesized an increase in annual pediatric ICM implants starting in 2014 attributable to device miniaturization.

Methods and Results

A retrospective observational study was conducted using administrative claims from MarketScan Medicaid and commercial insurance claims databases. Use of ICM between January 2013 and December 2018 was measured (normalized to the total enrolled population ≤18 years) and compared with balancing measures (Holter ambulatory monitors, cardiac event monitors, encounters with syncope diagnosis, implantation of implantable cardioverter‐defibrillator/pacemaker). Secondary analyses included evaluations of subsequent interventions and complications. The study cohort included 33 532 185 individual subjects, of which 769 (0.002%) underwent ICM implantation. Subjects who underwent ICM implantation were 52% male sex, with a median age of 16 years (interquartile range, 10–17 years). A history of syncope was present in 71%, palpitations in 43%, and congenital heart disease in 28%. Following release of the miniaturized ICM, use of ICMs increased from 5 procedures per million enrollees in 2013 to 11 per million between 2015 and 2018 (P<0.001), while balancing measures remained static. Of 394 subjects with ≥1 year of follow‐up after implantation, interventions included catheter ablation in 24 (6%), pacemaker implantation in 15 (4%), and implantable cardioverter‐defibrillator implantation in 7 (2%).

Conclusions

Introduction of the miniaturized ICM was followed by a rapid increase in pediatric use. The effects on outcomes and value deserve further attention.

Current evidence for pharmacologic therapy following stage 1 palliation for single ventricle congenital heart disease

INTRODUCTION

Infants with single ventricle congenital heart disease are vulnerable to complications between stage 1 and stage 2 of palliation. Pharmaceutical treatment during this period is varied and often dependent on institutional practices as there is little evidence supporting a particular treatment path.

AREAS COVERED

This review focuses on medical management of patients following stage I palliation. We performed a scoping review of the current literature regarding angiotensin converting enzyme inhibitors and digoxin treatment in the interstage period. In addition, we discuss other medication classes frequently used in these patients.

EXPERT OPINION

Due to significant heterogeneity of anatomy, rarity of disease, and other confounding factors, there is limited evidence to support most commonly used medications within the interstage period. Digoxin is associated with improved mortality within the interstage period and should be considered; however, no large randomized controlled trial exists supporting its use. Prevention of thrombotic complication with aspirin is also associated with improved outcomes and should be considered unless a contraindication exists. The addition of other prescriptions in this patient population should be considered only after an evaluation of the risks and benefits of each medication, recognizing the burden and risk of polypharmacy in this fragile patient population.

Prevalent pharmacotherapy of US Fontan survivors: A study utilizing data from the MarketScan Commercial and Medicaid claims databases

BACKGROUND

Survivors of Fontan palliation are at life-long risk of thrombosis, arrhythmia, and circulatory failure. To our knowledge, no studies have evaluated current United States pharmaceutical prescription practice in this population.

METHODS

A retrospective observational study evaluating the prevalent use of prescription medications in children and adolescents with hypoplastic left heart syndrome or tricuspid atresia after Fontan completion (identified using ICD9/10 codes) was performed using data contained in the MarketScan Commercial and Medicaid databases for the years 2013 through 2018. Cardiac pharmaceuticals were divided by class. Anticoagulant agents other than platelet inhibitors, which are not uniformly a prescription medication, were also studied. Associations between increasing age and the likelihood of a filled prescription for each class of drug were evaluated. Annualized retail costs of pharmaceutical regimens were calculated.

RESULTS

A cohort of 4,056 subjects (median age 12 years [interquartile range: 8-16], 61% male, 60% commercial insurance) was identified. Of the cohort, 50% received no prescription medications. Angiotensin converting enzyme inhibitors/angiotensin receptor blockers (ACEi/ARB) (38%), diuretics (15%), and mineralocorticoid receptor antagonists (8%) were prescribed with the highest frequency. Pulmonary vasodilators were received by 6% of subjects. Older age was associated with increased likelihood of filled prescriptions for anticoagulants (P = .008), antiarrhythmic agents, digoxin, ACEi/ARB, and beta blockers (each P < .0001), but also lower likelihood of filled prescriptions for pulmonary vasodilators, conventional diuretics (both P < .0001), and mineralocorticoid receptor antagonists (P = .02).

CONCLUSIONS

Pharmaceuticals typically used to treat heart failure and pulmonary hypertension are the most commonly prescribed medications following Fontan palliation. While the likelihood of treatment with a particular class of medication is associated with the age of the patient, determining the optimal regimen for individual patients and the population at large is an important knowledge gap for future research.

Impact of Digoxin Use on Interstage Outcomes of Single Ventricle Heart Disease (From a NPC-QIC Registry Analysis)

Digoxin has been associated with lower interstage mortality (ISM) following stage 1 palliation (S1P). Despite a substantial increase in digoxin use nationally, ISM has not declined. We aimed to determine the impact of digoxin on ISM in the current era. This study analyzed data from the National Pediatric Cardiology Quality Improvement Collaborative (NPC-QIC) registry. All patients who survived to hospital discharge following S1P were included. Comparisons were made between pre-specified eras (1: 2010-2015, 2: 2016-2019) based on digoxin use. ISM risk was estimated using the previously published NEONATE score (excluding digoxin). Multivariable Cox proportional hazard models assessed the impact of digoxin on ISM and freedom from unplanned readmission in era 2. A total of 1400 (46.8%) patients were included from era 1 and 1589 (53.2%) from era 2. Digoxin use (22.4% vs 61.7%, p < 0.001) and the proportion of high-risk patients (9.1% vs 20.3%, p < 0.001) increased across eras. There was no difference in predicted ISM risk between those who did vs did not receive digoxin in era 2 (p = 0.82). In era 2, digoxin use was independently associated with lower ISM (AHR 0.60, 95%CI 0.36 to 0.98, p = 0.043) and greater freedom from unplanned readmission (AHR 0.44, 95%CI 0.32 - 0.59, p < 0.001). In conclusion, digoxin is independently associated with lower ISM and greater freedom from interstage readmission. The lack of improvement in overall ISM in the current era may be secondary to a greater proportion of high-risk patients and/or disproportionately higher digoxin use in lower risk patients, who may not derive the same benefit.