Effectiveness of low dose captopril versus propranolol therapy in infants with severe congestive failure due to left-to-right shunts

Application of a physiologically based pharmacokinetic model in predicting captopril disposition in children with chronic kidney disease

Over the last several decades, angiotensin-converting enzyme inhibitors (ACEIs) have been a staple in the treatment of hypertension and renovascular disorders in children. One of the ACEIs, captopril, is projected to have all the benefits of traditional vasodilators. However, conducting clinical trials for determining the pharmacokinetics (PK) of a drug is challenging, particularly in pediatrics. As a result, modeling and simulation methods have been developed to identify the safe and effective dosages of drugs. The physiologically based pharmacokinetic (PBPK) modeling is a well-established method that permits extrapolation from adult to juvenile populations. By using SIMCYP simulator, as a modeling platform, a previously developed PBPK drug-disease model of captopril was scaled to renally impaired pediatrics population for predicting captopril PK. The visual predictive checks, predicted/observed ratios (ratio_pred/obs), and the average fold error of PK parameters were used for model evaluation. The model predictions were comparable with the reported PK data of captopril in mild and severe chronic kidney disease (CKD) patients, as the mean ratio_pred/obs C_max and AUC_0-t were 1.44 (95% CI 1.07 - 1.80) and 1.26 (95% CI 0.93 - 1.59), respectively. The successfully developed captopril-CKD pediatric model can be used in suggesting drug dosing in children diagnosed with different stages of CKD.

Can Pediatric Heart Failure Therapy Be Improved? Yes It Can, But…

Given the heterogenous etiology of pediatric heart failure (pHF), evidence-based studies improving pHF are unlikely. A paradigm shift towards updated medicine-based evidence is therefore necessary. In view of the life expectancy of children, cardiac regeneration strategies are required. Therefore, age- and disease-related differences in myocardial (receptor) physiology require individualized precision medicine. First-line diuretic therapy, adopted from the treatment of adults with HF with no chance for recovery, should be questioned in the treatment of pHF with potential for recovery. Inadequate use of diuretics is a common reason for additional stimulation of the neurohumoral axis. Consecutive intravascular volume depletion led to an inadequate treatment with β-blocker and renin-angiotensin-aldosterone antagonists. Given the age-related catecholamine-driven cardiovascular (patho-) physiology, highly selective β1-blockers (bisoprolol) protect against β1-(noradrenaline)-related myocytic apoptosis and necrosis, but allow β2-receptor-mediated myocardial regeneration. Based on its high safety-efficacy profile with rarely seen adverse effects but easily monitorable efficacy by the surrogate of heart rate (reduction), bisoprolol is our first-line drug in infancy. Reduced heart rate economizes the heart and full body oxygen consumption and extends the diastolic filling and coronary perfusion time. Based on our many years of institutional experience, physicians should be encouraged to use β1-selected blockers in infants with dilated cardiomyopathy and hypoplastic left heart syndrome after stage-1 procedure, but also to treat ventricular septal defects with a significant left-to-right shunt. In summary, individualized pHF therapy is the prerequisite for a causal treatment to improve HF symptoms, but above all for the most functional regeneration possible.

A word on netting of angiotensin-converting enzyme inhibitor therapy in hypoplastic left heart syndrome following stage-I

NPC-QIC Registry data showed that angiotensin-converting enzyme inhibitors were described in almost 38% for patients with single ventricle physiology after stage-I Norwood palliation. However, mortality and ventricular dysfunction or atrioventricular valve insufficiency seems to be not improved by oral application of angiotensin-converting enzyme inhibitors. The final conclusion was that despite limited evidence of benefit for patients with hypoplastic left heart syndrome, prescription of angiotensin-converting enzyme inhibitors during interstage is still common. Taking into account of the predominant cardiovascular regulation in newborns and young infants by circulating catecholamines, no real improvement is to be expected from angiotensin-converting enzyme inhibitor monotherapy. The goals of drug therapy after stage-I Norwood palliation in hypoplastic left heart syndrome are prevention of systemic right ventricle failure, balancing pulmonary and systemic blood flow, and reduction of oxygen consumption with regard to limitations of oxygen supply by the single ventricle, furthermore, avoiding harmful effects of endogenous catecholamine production in the long term on somatic and cognitive development. In this light of knowledge, we want to recommend the use of a long-acting and highly specific ß1-adrenoreceptor blocker for almost all patients after stage-I Norwood palliation and a combination with angiotensin-converting enzyme inhibitors only by indication after exclusion of potential side effects.

Efficacy and safety of propranolol in infants with heart failure due to moderate-to-large ventricular septal defect (VSD-PHF study) - A prospective randomized trial

AIMS

The utility of beta-blocker therapy in infants with heart failure (HF) due to significant left-to-right shunt lesions is not known. The study aimed to assess the efficacy and safety of propranolol in infants with HF due to moderate-to-large ventricular septal defect (VSD).

METHODS

The prospective randomized trial included 80 infants with HF and moderate-to-large VSD, randomly allocated to receive either conventional therapy alone (n = 40) or propranolol plus conventional therapy (n = 40). The primary endpoint was a composite of all-cause mortality, hospitalization for HF and/or chest infection, and referral for surgery. The secondary clinical outcomes were the individual components of the composite endpoint. In addition, the patients were followed up to detect safety outcomes, for example, bronchospasm, bradyarrhythmia, and worsening HF symptoms.

RESULTS

The addition of propranolol therapy to the conventional medications did not result in significant improvement in the primary composite endpoint (32.50% vs. 52.50%; P = 0.07). There was a trend toward improvement, but the study is underpowered for this important question. However, propranolol therapy significantly decreased the risk of hospitalization (12.50% vs. 32.50%; P = 0.03) and worsening of Ross HF class (5.41% vs. 28.21%; P = 0.01) as compared to conventional therapy (estimated number needed to treat = 5). Propranolol did not result in any significant safety concerns in these infants except bronchospasm in an infant.

CONCLUSIONS

Propranolol therapy in infants with significant left-to-right shunt may prevent worsening in HF symptoms and hospitalization and is well tolerated. However, it does not reduce mortality or need for surgery.

Cardiovascular Drug Therapy during Interstage After Hybrid Approach: A Single-Center Experience in 51 Newborns with Hypoplastic Left Heart

BACKGROUND

Newborns with hypoplastic left heart (HLH) are usually palliated with the Norwood procedure or a hybrid stage I procedure. Hybrid is our preferred approach. Given the critical relationship between stage I, interstage, and comprehensive stage II or advanced biventricular repair, we hypothesized that appropriate drug treatment is a significant therapeutic cornerstone, especially for the management of the high-risk interstage.

METHODS

We report a single-center observational study addressing the cardiovascular effects of, in particular, oral β-blockers and the additional use of angiotensin-converting enzyme (ACE) and mineralocorticoid inhibitors.

RESULTS

In total, 51 newborns-30 with HLH syndrome (HLHS) and 21 with HLH complex (HLHC)-with a median bodyweight of 3.0 kg (range 1.9-4.4; nine with bodyweight ≤ 2500 g) underwent an uneventful "Giessen hybrid approach" using a newly approved duct stent. All patients were discharged home with a single, double or triple therapy consisting of ß-blockers, ACE and mineralocorticoid inhibitors; 90% of the patients received bisoprolol, 10% received propranolol, 72% received lisinopril, and 78% received spironolactone. Resting heart rate decreased from 138 bpm (range 112-172; n = 51) at admission to 123 bpm (range 99-139; n = 51) at discharge and 110 bpm before stage II/biventricular repair/heart transplantation (range 90-140; n = 37) accompanied by favorable bodyweight gain. No side effects were evident.

CONCLUSION

In view of drug risk/benefit profiles, as well as the variable morphology and hemodynamics, the highly selective β1-adrenoceptor blocker bisoprolol is our preferred drug for treatment of HLHS/HLHC in the interstage. We avoid using ACE inhibitor monotherapy and exclude potential risks for coronary and cerebral perfusion pressure beforehand.

Biomarkers in congenital heart disease: do natriuretic peptides hold the key?

Congenital heart disease is the most common congenital abnormality. The long-term prognosis of these patients has changed significantly over the last half century, thanks to improvements in cardiovascular diagnosis, surgery and postoperative care. However, residual lesions are not uncommon and many of the interventions performed remain palliative rather than reparative, leading to the development of ventricular dysfunction and heart failure. Natriuretic peptides are well-established markers of disease severity and prognosis in patients with heart failure due to noncongenital (acquired) heart disease. However, the role of biomarkers in congenital heart disease is unclear. This review highlights the impact of neurohormonal activation in patients with congenital heart disease, as well as the usefulness of assessing natriuretic peptide levels in specific clinical situations.

Anaesthetic and post-operative management of a modified Norwood operation for hypoplastic left heart syndrome: a retrospective series of 11 cases

OBJECTIVE

This study aimed to describe the pre-operative and operative findings, as well as the post-operative haemodynamics of patients operated on for hypoplastic left heart. The findings of patients who survived or did not survive were also compared to anticipate the risk factors for mortality.

METHODS

We retrospectively reviewed the anaesthetic and intensive care records of 11 (seven male and four female) patients who underwent a modified Norwood operation as neonates. There were eight patients who survived, while three did not survive after the operation. Haemodynamics, oxygenation, and medications of patients were recorded for the pre-operative and post-operative conditions for 2 days, and compared between groups of patients who survived and those who did not.

RESULTS

The normalised modified Blalock-Taussig shunt area was 3.28, 0.57 square millimetres per kilogram (mean, standard deviation) for the group of patients who survived and 3.55, 1.4 square millimetres per kilogram for the group of patients who did not survive (p = 0.51). The group of patients who survived had a significantly larger normalised aortic annulus area (3.3, 0.89 square millimetres per kilogram versus 1.68, 0.21 square millimetres per kilogram, p = 0.01), lower median age (5.57 (3-8) days versus 46.67 (4-90) days, p = 0.02), and lower weight (2.95, 0.46 kilograms versus 3.85, 0.56 kilograms, p = 0.03) than the group of patients who did not survive. Furthermore, the group of patients who did not survive had a significantly worse pre-operative condition, lower systemic venous and arterial oxygen saturation, and need for a high dose of drugs in the pre-operative and post-operative periods (p was less than 0.05 for each variable).

CONCLUSION

The pre-operative, operative, and post-operative findings may be related to mortality early after the modified Norwood operation for hypoplastic left heart syndrome.

Side effects of angiotensin converting enzyme inhibitor (captopril) in newborns and young infants

AIM

To analyze the side effects of captopril, an angiotensin converting enzyme inhibitor (ACEI) in newborn and young infants.

METHODS

Retrospective analysis of side effects in 43 patients with congenital heart disease after cardiac surgery treated with captopril for heart failure during a two-year period.

RESULTS

Median age of the patients was 26 days (range 6-310 days), median weight 3.5 kg (range 1.9-7.9 kg). Initial median dose of captopril was 0.17 mg/kg/day (range 0.05-0.55 mg/kg/day), slowly increased over 3-33 days to a maximal median dose of 1.86 mg/kg/day (range 0.2-2.3 mg/kg/day). All patients were additionally treated with diuretics. Side effects occurred in 17 patients (renal impairment or failure in 6, low blood pressure in 8, and oxygen saturation deficit in 3) requiring cessation or interruption in seven patients with renal impairment/failure (n=4), hypotension (n=1) and aorto-pulmonary shunting with low pulmonary perfusion (n=2). The six children who developed renal impairment or failure did so following a median delay of nine days after reaching the final dose and weighed on average 500 g less than the other patients (P=0.046). All side effects were fully reversible.

CONCLUSION

Side effects due to captopril were not dose-related in newborns and infants in this study. However, renal side effects occurred more often in smaller infants. Routine monitoring of infants on ACEI should include renal function tests, blood pressure and transcutaneous oxygen saturation measurements.

Exercise Intolerance in Adults with Congenital Heart Disease

This article describes the ways to assess exercise capacity in adults with congenital heart disease (ACHD) and the impact of exercise intolerance in the population. It also discusses the likely pathogenesis of exercise intolerance in ACHD, the similarities between ACHD and acquired heart failure, and potential therapeutic options.

Direction, location, and size of shunt flow in congenital heart disease evaluated by ECG-gated multislice computed tomography

OBJECTIVE

To demonstrate the utility of multislice computed tomography (MSCT) in the evaluation of direction, location, and size of shunt flow in congenital heart disease.

BACKGROUND

Transthoracic and transesophageal echocardiography, magnetic resonance imaging, and conventional angiography has been used to evaluate congenital heart disease; however, some are invasive and some do not provide accurate information about the spatial relationship to other organs.

METHODS

Three patients with typical presentation of ventricular septal defect, atrial septal defect, and patent ductus arteriosus were recruited. Enhanced MSCT (Light Speed Ultra 16, General Electric) was performed with a 1.25-mm slice thickness, helical pitch 3.25. Following intravenous injection of 100 ml of iodinated contrast material (350 mg I/ml) at a rate of 3 ml/s, CT scanning was performed with retrospective ECG-gated reconstruction at 5 s and 30 s after injection.

RESULTS

In all cases the information of direction, location, and size of shunt flow including left-to-right and right-to-left shunt with spatial relationship to other organs could be obtained non-invasively.

CONCLUSION

ECG-gated MSCT is a useful tool to evaluate congenital heart diseases with shunts.

Applying standard therapies to new targets: the use of ACE inhibitors and B-blockers for heart failure in adults with congenital heart disease

Increasingly, patients and clinicians are being confronted with congestive heart failure (CHF) as a late complication of congenital heart disease. However, medical management of heart failure in this patient group represents a challenge because of complex hemodynamics and a lack of evidence from large randomized controlled trials to guide therapy. This article will review the evidence of the use angiotensin converting enzyme inhibitors (ACEIs) and beta-blockers (BBs) in left heart failure, discuss the mechanisms of heart failure as they pertain to congenital heart disease and review the limited literature of the use of neurohormonal antagonists in congenital heart disease. Some recommendations for use of angiotensin converting enzyme inhibitors and beta-blockers in heart failure due various congenital heart lesions are offered. Well-designed clinical trials are urgently needed to extend the impressive reductions in morbidity and mortality achieved with neurohormonal blockade in left ventricular (LV) heart failure to adults with congenital heart disease.

CAPRICORN: a story of alpha allocation and beta-blockers in left ventricular dysfunction post-MI

Beta-blocker therapy is beneficial both after myocardial infarction and in mild, moderate and severe chronic heart failure. Recent sub-group analysis of the Goteborg Metoprolol Trial and the AIRE study confirm that patients receiving beta-blockers in the setting of post-MI heart failure fare better than patients not receiving this therapy. For all these reasons the CAPRICORN trial of carvedilol in post-MI LV dysfunction was an important and eagerly awaited trial. The results were presented for the first time at The American College of Cardiology on March 20 2001. CAPRICORN randomised 984 patients to placebo and 975 to carvedilol between 3 and 21 days (mean 10) after a confirmed MI. Patients had to have evidence of a left ventricular ejection fraction 40% or less. All patients had received ACEI therapy for at least 48 hours prior to randomisation. The mean ejection fraction of the patients recruited was 32.7% in the placebo group and 32.9% in the carvedilol group. Follow-up was for a mean of 15 months (maximum 2.7 years). All cause mortality was 15.3% (151 deaths) in the placebo group and 11.9% (116 deaths) in the carvedilol group, giving a hazard ratio of 0.77 (0.60-0.98) and a significance of p = 0.031. And yet this agent will probably not be given a licence for this indication in the European Union and the USA. The reason is one of trial design and statistical declarations. Some way into the trial the Steering Committee decided to change the primary end-point form all-cause mortality to two co-primary end-points and to allocate their alpha power of 0.05 unevenly between the combined end-points of all cause mortality and cardiovascular hospitalisation (alpha 0.045) and all cause mortality (alpha 0.005). In the end neither was achieved, one because of the large number of non-specific hospitalisations for chest pain and the mortality effect because it was allocated a punitive and unachievable target of p < 0.005. The trial is thus officially neutral despite showing convincing clinical benefit. Clearly arcane matters of statistical plans do matter and steering committees should think very carefully before changing the primary end-points of major trials.