Randomized controlled trials in children's heart surgery in the 21st century: a systematic review

Myocardial protection in paediatric cardiac surgery: building an evidence-based strategy

Cardioplegia is fundamental to the surgical repair of congenital heart defects by protecting the heart against ischaemia/reperfusion injury, characterised by low cardiac output and troponin release in the early postoperative period. The immature myocardium exhibits structural, physiological and metabolic differences from the adult heart, with a greater sensitivity to calcium overload-mediated injury during reperfusion. Del Nido cardioplegia was designed specifically to protect the immature heart, is widely used in North America and may provide better myocardial protection in children; however, it has not been commercially available in the UK, where most centres use St Thomas' blood cardioplegia. There are no phase 3 clinical trials in children to support one solution over another and this lack of evidence, combined with variations in practice, suggests the presence of clinical equipoise. The best cardioplegia solution for use in children, and the impact of age and other clinical factors remain unknown. In this Hunterian lecture, I propose an evidence-based strategy to improve myocardial protection during cardiac surgery in children through: (1) conducting multicentre clinical trials of established techniques; (2) improving our knowledge of ischaemia/reperfusion injury in the setting of cardioplegic arrest; (3) applying this to drive innovation, moving beyond current cardioplegia solutions; (4) empowering personalised medicine, through combining clinical and genomic data, including ethnic diversity; and (5) understanding the impact of cardioplegic arrest on the late outcomes that matter to patients and their families.

Implementing early rehabilitation and mobilisation for children in UK paediatric intensive care units: the PERMIT feasibility study

Background

Early rehabilitation and mobilisation encompass patient-tailored interventions, delivered within intensive care, but there are few studies in children and young people within paediatric intensive care units.

Objectives

To explore how healthcare professionals currently practise early rehabilitation and mobilisation using qualitative and quantitative approaches; co-design the Paediatric Early Rehabilitation and Mobilisation during InTensive care manual of early rehabilitation and mobilisation interventions, with primary and secondary patient-centred outcomes; explore feasibility and acceptability of implementing the Paediatric Early Rehabilitation and Mobilisation during InTensive care manual within three paediatric intensive care units.

Design

Mixed-methods feasibility with five interlinked studies (scoping review, survey, observational study, codesign workshops, feasibility study) in three phases.

Setting

United Kingdom paediatric intensive care units.

Participants

Children and young people aged 0-16 years remaining within paediatric intensive care on day 3, their parents/guardians and healthcare professionals.

Interventions

In Phase 3, unit-wide implementation of manualised early rehabilitation and mobilisation.

Main outcome measures

Phase 1 observational study: prevalence of any early rehabilitation and mobilisation on day 3. Phase 3 feasibility study: acceptability of early rehabilitation and mobilisation intervention; adverse events; acceptability of study design; acceptability of outcome measures.

Data sources

Searched Excerpta Medica Database, Cumulative Index to Nursing and Allied Health Literature, MEDLINE, PEDro, Open grey and Cochrane CENTRAL databases.

Review methods

Narrative synthesis.

Results

In the scoping review we identified 36 full-text reports evaluating rehabilitation initiated within 7 days of paediatric intensive care unit admission, outlining non-mobility and mobility early rehabilitation and mobilisation interventions from 24 to 72 hours and delivered twice daily. With the survey, 124/191 (65%) responded from 26/29 (90%) United Kingdom paediatric intensive care units; the majority considered early rehabilitation and mobilisation a priority. The observational study followed 169 patients from 15 units; prevalence of any early rehabilitation and mobilisation on day 3 was 95.3%. We then developed a manualised early rehabilitation and mobilisation intervention informed by current evidence, experience and theory. All three sites implemented the Paediatric Early Rehabilitation and Mobilisation during InTensive care manual successfully, recruited to target (30 patients recruited) and followed up the patients until day 30 or discharge; 21/30 parents consented to complete additional outcome measures.

Limitations

The findings represent the views of National Health Service staff but may not be generalisable. We were unable to conduct workshops and interviews with children, young people and parents to support the Paediatric Early Rehabilitation and Mobilisation during InTensive care manual development due to pandemic restrictions.

Conclusions

A randomised controlled trial is recommended to assess the effectiveness of the manualised early rehabilitation and mobilisation intervention.

Future work

A definitive cluster randomised trial of early rehabilitation and mobilisation in paediatric intensive care requires selection of outcome measure and health economic evaluation.

Study registration

The study is registered as PROSPERO CRD42019151050. The Phase 1 observational study is registered Clinicaltrials.gov NCT04110938 (Phase 1) (registered 1 October 2019) and the Phase 3 feasibility study is registered NCT04909762 (Phase 3) (registered 2 June 2021).

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: 17/21/06) and is published in full in Health Technology Assessment; Vol. 27, No. 27. See the NIHR Funding and Awards website for further award information.

Improving Outcomes for Infants After Cardiopulmonary Bypass Surgery for Congenital Heart Disease: A Commentary on Recent Randomized Controlled Trials

The recent NITRIC and STRESS trials demonstrate opportunities to perform pragmatic large randomized trials in congenital heart disease. We discuss lessons learnt from these trials which can inform future trial design and conduct in the field of pediatric heart surgery.

The paucity of high-level evidence for therapy in pediatric cardiology

Introduction

Clinical practice should be based on the highest quality of evidence available. Therefore, we aimed to classify publications in the field of pediatric cardiology in the year 2021 based on the level of scientific evidence.

Materials and Methods

A PubMed search was performed to identify pediatric cardiology articles published in the calendar year 2021. The abstract or manuscript of each study was reviewed. Each study was categorized as high, medium, or low level of evidence based on the study design. Disease investigated, treatment studied, and country of publication were recorded. Randomized control trials (RCTs) in similar fields of neonatology and adult cardiology were identified for comparison. Descriptive statistics were performed on the level of evidence, type of disease, country of publication, and therapeutic intervention.

Results

In 2021, 731 studies were identified. A decrease in prevalence for the level of evidence as a function of low, medium, and high was found (50.1%, 44.2%, and 5.8%, respectively). A low level of evidence studies was the majority for all types of cardiac disease identified, including acquired heart disease, arrhythmias, congenital heart disease, and heart failure, and for treatment modalities, including circulatory support, defibrillator, percutaneous intervention, medicine, and surgery. In a subgroup analysis, most high-level evidence studies were from the USA (31%), followed by China (26.2%) and India (14.3%). Comparing RCTs, 21 RCTs were identified in pediatric cardiology compared to 178 in neonatology and 413 in adult ischemic heart disease.

Conclusions

There is a great need for the conduct of studies that offer a high level of evidence in the discipline of pediatric cardiology.

Multicenter Clinical Research in Congenital Heart Disease: Leveraging Research Networks to Investigate Important Unanswered Questions

Congenital heart disease (CHD) is the most common birth defect in the United States. Neonates with CHD are often cared for by neonatologists in addition to cardiologists. However, there is a paucity of rigorous evidence and limited clinical trials regarding the management of neonates with CHD. In this review, we will describe some of the challenges of research in this field. The Pediatric Heart Network serves as an example of how a research network can effectively overcome barriers to conduct and execute well-designed multicenter studies.

Surgical-PEARL protocol: a multicentre prospective cohort study exploring aetiology, management and outcomes for patients with congenital anomalies potentially requiring surgical intervention

INTRODUCTION

Congenital anomalies affect over 2% of pregnancies. Surgical advances have reduced mortality and improved survival for patients with congenital anomalies potentially requiring surgical (CAPRS) intervention. However, our understanding of aetiology, diagnostic methods, optimal management, outcomes and prognostication is limited. Existing birth cohorts have low numbers of individual heterogenous CAPRS. The Surgical Paediatric congEnital Anomalies Registry with Long term follow-up (Surgical-PEARL) study aims to establish a multicentre prospective fetal, child and biological parent cohort of CAPRS.

METHODS AND ANALYSIS

From 2022 to 2027, Surgical-PEARL aims to recruit 2500 patients with CAPRS alongside their biological mothers and fathers from up to 15 UK centres. Recruitment will be antenatal or postnatal dependent on diagnosis timing and presentation to a recruitment site. Routine clinical data including antenatal scans and records, neonatal intensive care unit (NICU) records, diagnostic and surgical data and hospital episode statistics will be collected. A detailed biobank of samples will include: parents' blood and urine samples; amniotic fluid if available; children's blood and urine samples on admission to NICU, perioperatively or if the child has care withdrawn or is transferred for extracorporeal membrane oxygenation; stool samples; and surplus surgical tissue. Parents will complete questionnaires including sociodemographic and health data. Follow-up outcome and questionnaire data will be collected for 5 years. Once established we will explore the potential of comparing findings in Surgical-PEARL to general population cohorts born in the same years and centres.

ETHICS AND DISSEMINATION

Ethical and health research authority approvals have been granted (IRAS Project ID: 302251; REC reference number 22/SS/0004). Surgical-PEARL is adopted onto the National Institute for Health Research Clinical Research Network portfolio. Findings will be disseminated widely through peer-reviewed publication, conference presentations and through patient organisations and newsletters.

TRIAL REGISTRATION NUMBER

ISRCTN12557586.

Research priorities in children and adults with congenital heart disease: a James Lind Alliance Priority Setting Partnership

OBJECTIVE

To bring together patients, parents, charities and clinicians in a Priority Setting Partnership to establish national clinical priorities for research in children and adults with congenital heart disease.

METHODS

The established James Lind Alliance methodology was used to identify and prioritise research on the management of congenital heart disease, focusing on diagnosis, treatment and outcomes. An initial open survey was used to gather potential uncertainties which were filtered, categorised, converted into summary questions and checked against current evidence. In a second survey, respondents identified the unanswered questions most important to them. At two final workshops, patients, parents, charities and healthcare professionals agreed the top 10 lists of priorities for child/antenatal and adult congenital heart disease research.

RESULTS

524 respondents submitted 1373 individual questions, from which 313 out of scope or duplicate questions were removed. The remaining 1060 questions were distilled into summary questions and checked against existing literature, with only three questions deemed entirely answered and removed. 250 respondents completed the child/antenatal survey (56 uncertainties) and 252 completed the adult survey (47 uncertainties). The questions ranked the highest by clinicians and non-clinicians were taken forward to consensus workshops, where two sets of top 10 research priorities were agreed.

CONCLUSIONS

Through an established and equitable process, we determined national clinical priorities for congenital heart disease research. These will be taken forward by specific working groups, a national patient and public involvement group, and through the establishment of a UK and Ireland network for collaborative, multicentre clinical trials in congenital heart disease.

A Survey of Resources and Nursing Workforce for Clinical Research Delivery in Paediatric Intensive Care Within the UK / Ireland

Introduction

Clinical research within Paediatric Intensive Care (PICU) is necessary to reduce morbidity and mortality associated within this resource-intensive environment. With UK PICUs encouraged to be research-active there was a drive to understand how centres support research delivery.

Aim

To identify the research workforce available within UK/Ireland PICUs to support clinical research delivery.

Method

An electronic survey, endorsed by the Paediatric Critical Care Society (PCCS), was designed and reported in accordance with CHERRIES guidelines. The survey was distributed by email to all UK/Ireland Nurse Managers and Medical/ Nursing Research leads, aiming for one response per site during the period of April-June 2021. Only one response per site was included in analysis.

Results

44 responses were received, representing 24/30 UK/Ireland sites (80% response rate). Responses from n = 21/30 units are included (three excluded for insufficient data). 90% (n = 19/21) units were research active, although only 52% (n = 11) had permanent research roles funded within their staffing establishment. The majority of units (n = 18, 86%) had less than two WTE research nurses. Resources were felt to be sufficient for current research delivery by 43% of units (n = 9), but this confidence diminished to 19% (n = 4) when considering their ability to support future research. The top barriers to research conduct were insufficiently funded/unfunded studies (52%; n = 11), clinical staff too busy to support research activity (52%; n = 11) and short-term/fixed-term contracts for research staff (38%; n = 8).

Conclusion

Despite the perceived importance of research and 90% of responding UK/Ireland PICUs being research active, the majority have limited resources to support research delivery. This has implications for their ability to participate in future multi-centre trials and opportunities to support the development of future medical/nursing clinical academics. Further work is required to identify optimum models of clinical research delivery.

Medicine-Based Evidence in Congenital Heart Disease: How Artificial Intelligence Can Guide Treatment Decisions for Individual Patients

Built on the foundation of the randomized controlled trial (RCT), Evidence Based Medicine (EBM) is at its best when optimizing outcomes for homogeneous cohorts of patients like those participating in an RCT. Its weakness is a failure to resolve a clinical quandary: patients appear for care individually, each may differ in important ways from an RCT cohort, and the physician will wonder each time if following EBM will provide best guidance for this unique patient. In an effort to overcome this weakness, and promote higher quality care through a more personalized approach, a new framework has been proposed: Medicine-Based Evidence (MBE). In this approach, big data and deep learning techniques are embraced to interrogate treatment responses among patients in real-world clinical practice. Such statistical models are then integrated with mechanistic disease models to construct a “digital twin,” which serves as the real-time digital counterpart of a patient. MBE is thereby capable of dynamically modeling the effects of various treatment decisions in the context of an individual's specific characteristics. In this article, we discuss how MBE could benefit patients with congenital heart disease, a field where RCTs are difficult to conduct and often fail to provide definitive solutions because of a small number of subjects, their clinical complexity, and heterogeneity. We will also highlight the challenges that must be addressed before MBE can be embraced in clinical practice and its full potential can be realized.

Standing on the shoulders of Giants: a citation analysis of the paediatric congenital heart disease literature

OBJECTIVE

The citation history of a published article reflects its impact on the literature over time. We conducted a comprehensive bibliometric analysis to identify the most cited papers on CHD in children.

METHODS

One-hundred and ninety journals listed in Journal Citation Reports were accessed via Web of Science. Publications with 250 or more citations were identified from Science Citation Index Expanded (1900-2020), and those relating to structural CHD in children were reviewed. Articles were ranked by citation count and the 100 most cited were analysed.

RESULTS

The number of citations ranged from 2522 to 309 (median 431, IQR 356-518), with 35 published since 2000. All were written in English, most originated from the United States (74%), and were published in cardiovascular journals, with Circulation (28%) the most frequent. There were 86 original research articles, including 50 case series, 14 cohort studies, and 10 clinical trials. The most cited paper was by Hoffman JI and Kaplan S on the incidence of CHD. Thirteen authors had 4 or more publications in the top 100, all of whom had worked in Boston, Philadelphia, San Francisco, or Dallas, and the most prolific author was Newburger JW (9 articles).

CONCLUSIONS

Citation analysis provides a historical perspective on scientific progress by assessing the impact of individual articles. Our study highlights the dominant position of US-based researchers and journals in this field. Most of the highly cited articles remain case series, with few randomised controlled trials in CHD appearing in recent years.

Unique Challenges of Randomised Controlled Trials in Pediatric Cardiology

Pediatric cardiology has evolved over time with reductions in childhood mortality due to congenital heart disease. Surgical innovation drove early changes in care. Increasingly, the need for more robust evidence provided by randomised controlled trials (RCTs) has been recognised. Although the number of RCTs has increased, there remains a relative paucity of truly impactful trials in the field. However, those trials that have changed practice have demonstrated the potential and importance of this work. Examples include the PRIMACORP trial, which established the safety and efficacy of milrinone after cardiac surgery, and the Single Ventricle Reconstruction trial, which was the first multicentre pediatric cardiac surgical RCT. The successful conduct and important findings emanating from these trials serve as beacons as clinicians strive to improve the evidence base in this field. The establishment of national and international networks such as the Pediatric Heart Network and the Canadian Pediatric Cardiology Research Network provide a strong foundation for future collaborative work. Despite this progress, there remain important challenges to designing and executing RCTs in pediatric cardiology. These include issues of greater disease and patient heterogeneity and increased costs. The use of innovative study designs and analytic methods and the establishment of core outcome measures have the potential to overcome some of the issues related to the smaller patient numbers compared with adult disciplines. As pediatric cardiologists look to the future, it is imperative that we work together to derive the maximum benefit from the considerable efforts directed toward conducting impactful clinical trials in pediatric cardiology.

Understanding parents' decision-making on participation in clinical trials in children's heart surgery: a qualitative study

OBJECTIVES

Few children undergoing heart surgery are recruited to clinical trials and little is known about the views and attitudes of parents towards trials. This study explored parents' perspectives on decision-making about their child's participation in a clinical trial during their elective cardiac surgery.

DESIGN

Qualitative interview study.

SETTING

Single-centre substudy of a multicentre, double-blind, randomised controlled trial to investigate the effects of remote ischaemic preconditioning in children undergoing cardiac surgery.

PARTICIPANTS

Parents of children approached to participate in the trial, both consenters and decliners.

METHODS

Semistructured interviews were conducted face-to-face or by telephone following discharge, digitally audio-recorded, transcribed and thematically analysed.

RESULTS

Of 46 patients approached for the trial, 24 consenting and 2 declining parents agreed to participate in an interview (21 mothers, 5 fathers). Parental decision-making about research was influenced by (1) potential risks or additional procedures; (2) personal benefit and altruism for the 'cardiac community'; (3) information, preparation, timing and approach; and (4) trust in the clinical team and collaboration with researchers. All of these were placed within the context of their understanding of the trial and knowledge of research.

CONCLUSIONS

Parents of children undergoing cardiac surgery attach value to clinical research and are supportive of clinical trials when there is no or minimal perceived additional risk. These findings enhance our understanding of the factors that influence parents' decision-making and should be used to inform the design and conduct of future paediatric surgical trials.

TRIAL REGISTRATION NUMBER

ISRCTN12923441; Pre-results.

Challenges to randomized trials in adult and congenital cardiac and thoracic surgery

Randomized trials in surgery face additional challenges compared to those in medicine. Some of the challenges are intrinsic to the nature of the field (such as issues with blinding, learning curve and surgeons experience and difficulties in defining the appropriate timing for comparative trials). Other issues are due to the surgical culture, the attitude of surgeons toward randomized trials and the lack of support by professional and national bodies. In this review a group with experience in trials in congenital and adult cardiac and thoracic surgery discusses the key issues with surgical trials and suggest potential solutions.

Identification and Evaluation of Controlled Trials in Pediatric Cardiology: Crowdsourced Scoping Review and Creation of Accessible Searchable Database

Cardiac disease in children is associated with significant morbidity and mortality as well as increased health resource utilisation. There is a perception that there is a paucity of high-quality studies, particularly randomized controlled trials (RCTs), in the field of pediatric cardiology. We sought to identify, examine, and map the range of RCTs conducted in children with cardiac conditions, including the development of a searchable open-access database. A literature search was conducted encompassing MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials from inception to 2018. All English-language RCTs enrolling children (age 0-21 years) with cardiac conditions were included. Data extraction and risk of bias assessments were performed in duplicate via crowdsourcing for each eligible study and entered into an online database. A total of 933 RCTs met eligibility criteria. Median trial recruitment was 49 patients (interquartile range 30-86) with 18.9% of studies (n = 176) including > 100 patients. A wide variety of populations and interventions were encompassed with congenital heart disease (79.8% of RCTs) and medications (63.3% of RCTs) often studied. Just over one-half of the trials (53.4%) clearly identified a primary outcome, and fewer than half (46.6%) fully documented a robust randomization process. Trials were summarised in a searchable online database (https://pediatrics.knack.com/cardiology-rct-database#cardiology-rcts/). Contrary to a commonly held perception, there are nearly 1,000 published RCTs in pediatric cardiology. The open-access database created as part of this project provides a resource that facilitates an efficient comprehensive review of the literature for clinicians and researchers caring for children with cardiac issues.

Bilateral Remote Ischaemic Conditioning in Children (BRICC) trial: protocol for a two-centre, double-blind, randomised controlled trial in young children undergoing cardiac surgery

INTRODUCTION

Myocardial protection against ischaemic-reperfusion injury is a key determinant of heart function and outcome following cardiac surgery in children. However, with current strategies, myocardial injury occurs routinely following aortic cross-clamping, as demonstrated by the ubiquitous rise in circulating troponin. Remote ischaemic preconditioning, the application of brief, non-lethal cycles of ischaemia and reperfusion to a distant organ or tissue, is a simple, low-risk and readily available technique which may improve myocardial protection. The Bilateral Remote Ischaemic Conditioning in Children (BRICC) trial will assess whether remote ischaemic preconditioning, applied to both lower limbs immediately prior to surgery, reduces myocardial injury in cyanotic and acyanotic young children.

METHODS AND ANALYSIS

The BRICC trial is a two-centre, double-blind, randomised controlled trial recruiting up to 120 young children (age 3 months to 3 years) undergoing primary repair of tetralogy of Fallot or surgical closure of an isolated ventricular septal defect. Participants will be randomised in a 1:1 ratio to either bilateral remote ischaemic preconditioning (3×5 min cycles) or sham immediately prior to surgery, with follow-up until discharge from hospital or 30 days, whichever is sooner. The primary outcome is reduction in area under the time-concentration curve for high-sensitivity (hs) troponin-T release in the first 24 hours after aortic cross-clamp release. Secondary outcome measures include peak hs-troponin-T, vasoactive inotrope score, arterial lactate and central venous oxygen saturations in the first 12 hours, and lengths of stay in the paediatric intensive care unit and the hospital.

ETHICS AND DISSEMINATION

The trial was approved by the West Midlands-Solihull National Health Service Research Ethics Committee (16/WM/0309) on 5 August 2016. Findings will be disseminated to the academic community through peer-reviewed publications and presentation at national and international meetings. Parents will be informed of the results through a newsletter in conjunction with a local charity.

TRIAL REGISTRATION NUMBER

ISRCTN12923441.

Cardioplegia in paediatric cardiac surgery: a systematic review of randomized controlled trials

OBJECTIVES

Cardioplegia is the primary method for myocardial protection during cardiac surgery. We conducted a systematic review of randomized controlled trials of cardioplegia in children to evaluate the current evidence base.

METHODS

We searched MEDLINE, CENTRAL and LILACS and manually screened retrieved references and systematic reviews to identify all randomized controlled trials comparing cardioplegia solutions or additives in children undergoing cardiac surgery published in any language; secondary publications and those reporting inseparable adult data were excluded. Two or more reviewers independently screened studies for eligibility and extracted data; the Cochrane Risk of Bias tool was used to assess for potential biases.

RESULTS

We identified 26 trials randomizing 1596 children undergoing surgery; all were single-centre, Phase II trials, recruiting few patients (median 48, interquartile range 30-99). The most frequent comparison was blood versus crystalloid in 10 (38.5%) trials, and the most common end points were biomarkers of myocardial injury (17, 65.4%), inotrope requirements (15, 57.7%) and length of stay in the intensive care unit (11, 42.3%). However, the heterogeneity of patients, interventions and reported outcome measures prohibited meta-analysis. Overall risk of bias was high in 3 (11.5%) trials, unclear in 23 (88.5%) and low in none.

CONCLUSIONS

The current literature on cardioplegia in children contains no late phase trials. The small size, inconsistent use of end points and low quality of reported trials provide a limited evidence base to inform practice. A core outcome set of clinically important, standardized, validated end points for assessing myocardial protection in children should be developed to facilitate the conduct of high-quality, multicentre trials.

PROSPERO registration

CRD42017080205.

Critical components for designing and implementing randomized controlled trials

Randomized controlled trials (RCTs) are considered the first level of evidence to assess the efficacy of novel interventions/therapies. Proper design and implementation of an RCT can result in convincing causal inferences. RCTs often represent the gold standard for clinical trials when appropriately designed, conducted and reported. However, there are limitations in implementation of RCTs, including sufficiency of randomized allocation (especial for allocation concealment), implementing standard intervention, maintaining follow-up and statement of conflicting interests. Therefore, the basic principles of RCTs are outlined here so that pediatric investigators can further understand what is the best evidence based on RCTs. More importantly, the quality of pediatric RCTs may be improved by following challenges in pediatric clinical trials outlined here.