Twelve Years of Drug Prioritization to Help Accelerate Disease Modification Trials in Parkinson's Disease: The International Linked Clinical Trials initiative

In 2011, the UK medical research charity Cure Parkinson's set up the international Linked Clinical Trials (iLCT) committee to help expedite the clinical testing of potentially disease modifying therapies for Parkinson's disease (PD). The first committee meeting was held at the Van Andel Institute in Grand Rapids, Michigan in 2012. This group of PD experts has subsequently met annually to assess and prioritize agents that may slow the progression of this neurodegenerative condition, using a systematic approach based on preclinical, epidemiological and, where possible, clinical data. Over the last 12 years, 171 unique agents have been evaluated by the iLCT committee, and there have been 21 completed clinical studies and 20 ongoing trials associated with the initiative. In this review, we briefly outline the iLCT process as well as the clinical development and outcomes of some of the top prioritized agents. We also discuss a few of the lessons that have been learnt, and we conclude with a perspective on what the next decade may bring, including the introduction of multi-arm, multi-stage clinical trial platforms and the possibility of combination therapies for PD.

Trial of Lixisenatide in Early Parkinson's Disease

BACKGROUND

Lixisenatide, a glucagon-like peptide-1 receptor agonist used for the treatment of diabetes, has shown neuroprotective properties in a mouse model of Parkinson's disease.

METHODS

In this phase 2, double-blind, randomized, placebo-controlled trial, we assessed the effect of lixisenatide on the progression of motor disability in persons with Parkinson's disease. Participants in whom Parkinson's disease was diagnosed less than 3 years earlier, who were receiving a stable dose of medications to treat symptoms, and who did not have motor complications were randomly assigned in a 1:1 ratio to daily subcutaneous lixisenatide or placebo for 12 months, followed by a 2-month washout period. The primary end point was the change from baseline in scores on the Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) part III (range, 0 to 132, with higher scores indicating greater motor disability), which was assessed in patients in the on-medication state at 12 months. Secondary end points included other MDS-UPDRS subscores at 6, 12, and 14 months and doses of levodopa equivalent.

RESULTS

A total of 156 persons were enrolled, with 78 assigned to each group. MDS-UPDRS part III scores at baseline were approximately 15 in both groups. At 12 months, scores on the MDS-UPDRS part III had changed by -0.04 points (indicating improvement) in the lixisenatide group and 3.04 points (indicating worsening disability) in the placebo group (difference, 3.08; 95% confidence interval, 0.86 to 5.30; P = 0.007). At 14 months, after a 2-month washout period, the mean MDS-UPDRS motor scores in the off-medication state were 17.7 (95% CI, 15.7 to 19.7) with lixisenatide and 20.6 (95% CI, 18.5 to 22.8) with placebo. Other results relative to the secondary end points did not differ substantially between the groups. Nausea occurred in 46% of participants receiving lixisenatide, and vomiting occurred in 13%.

CONCLUSIONS

In participants with early Parkinson's disease, lixisenatide therapy resulted in less progression of motor disability than placebo at 12 months in a phase 2 trial but was associated with gastrointestinal side effects. Longer and larger trials are needed to determine the effects and safety of lixisenatide in persons with Parkinson's disease. (Funded by the French Ministry of Health and others; LIXIPARK ClinicalTrials.gov number, NCT03439943.).

Protocol for a randomized, placebo-controlled, double-blind phase IIa study of the safety, tolerability, and symptomatic efficacy of the ROCK-inhibitor Fasudil in patients with Parkinson's disease (ROCK-PD)

Background

The Rho-kinase (ROCK) inhibitor Fasudil has shown symptomatic and disease-modifying effects in Parkinson's disease (PD) models in vitro and in vivo. In Japan, Fasudil has been approved for the treatment of subarachnoid haemorrhage since 1995 and shows a favourable safety profile.

Objectives/design

To investigate the safety, tolerability, and symptomatic efficacy of ROCK-inhibitor Fasudil in comparison to placebo in a randomized, national, multicenter, double-blind phase IIa study in patients with PD.

Methods/analysis

We plan to include 75 patients with at least 'probable' PD (MDS criteria), Hoehn and Yahr stages 1-3, and age 30-80 years in 13 German study sites. Patients must be non-fluctuating and their response to PD medication must have been stable for 6 weeks. Patients will be randomly allocated to treatment with the oral investigational medicinal product (IMP) containing either Fasudil in two dosages, or placebo, for a total of 22 days. As primary analysis, non-inferiority of low/high dose of Fasudil on the combined endpoint consisting of occurrence of intolerance and/or treatment-related serious adverse events (SAEs) over 22 days will be assessed in a sequential order, starting with the lower dose. Secondary endpoints will include tolerability alone over 22 days and occurrence of treatment-related SAEs (SARs) over 22 and 50 days and will be compared on group level. Additional secondary endpoints include efficacy on motor and non-motor symptoms, measured on established scales, and will be assessed at several timepoints. Biomaterial will be collected to determine pharmacokinetics of Fasudil and its active metabolite, and to evaluate biomarkers of neurodegeneration.

Ethics/registration/discussion

After positive evaluation by the competent authority and the ethics committee, patient recruitment started in the 3rd quarter of 2023. ROCK-PD is registered with Eudra-CT (2021-003879-34) and clinicaltrials.gov (NCT05931575). Results of this trial can pave way for conducting extended-duration studies assessing both symptomatic efficacy and disease-modifying properties of Fasudil.

Parkinson's Disease Drug Therapies in the Clinical Trial Pipeline: 2023 Update

BACKGROUND

Since 2020, annual reports on the clinical development of new drug-based therapies for the neurodegenerative condition of Parkinson's disease (PD) have been generated. These reviews have followed the progress of both "symptomatic treatments" (ST - improves/reduces symptoms of the condition) and "disease modifying treatments" (DMT - attempts to delay/slow progression by addressing the underlying biology of PD). Additional efforts have been made to further categorize these experimental treatments based on their mechanisms of action and class of drug.

METHODS

A dataset of clinical trials for drug therapies in PD was obtained using trial data downloaded from the ClinicalTrials.gov online registry. A breakdown analysis of all the studies that were active as of January 31st, 2023, was conducted.

RESULTS

There was a total of 139 clinical trials registered on the ClinicalTrials.gov website as active (with 35 trials newly registered since our last report). Of these trials, 76 (55%) were considered ST and 63 (45%) were designated DMT. Similar to previous years, approximately a third of the studies were in Phase 1 (n = 47; 34%), half (n = 72, 52%) were in Phase 2 and there were 20 (14%) studies in Phase 3. Novel therapies again represented the most dominant group of experimental treatments in this year's report with 58 (42%) trials testing new agents. Repurposed drugs are present in a third (n = 49, 35%) of trials, with reformulations and new claims representing 19% and 4% of studies, respectively.

CONCLUSIONS

Our fourth annual review of active clinical trials evaluating ST and DMT therapeutics for PD demonstrates that the drug development pipeline is dynamic and evolving. The slow progress and lack of agents transitioning from Phase 2 to Phase 3 is concerning, but collective efforts by various stakeholders are being made to accelerate the clinical trial process, with the aim of bringing new therapies to the PD community sooner.

Parkinson's Disease Drug Therapies in the Clinical Trial Pipeline: 2022 Update

Background:

As the international community dealt with the ongoing COVID-19 pandemic, important progress continued to be made in the development of new drug-based therapies for the neurodegenerative condition of Parkinson’s disease (PD) in 2021. This progress included both “symptomatic treatments” (ST – improves/reduces symptoms of the condition) and “disease modifying treatments” (DMT - attempts to delay/slow progression by addressing the underlying biology of PD), which can be categorised further based on their mechanisms of action and class of drug.

Objective:

This report continues previous efforts to provide an overview of the pharmacological therapies - both ST and DMT - in clinical trials for PD during 2021– 2022, with the aim of creating greater awareness and involvement in the clinical trial process. We also hope to stimulate collaboration amongst all stakeholders, including industry, academia, advocacy organizations, and most importantly patient community.

Methods:

We conducted a review of clinical trials of drug therapies for PD using trial data obtained from the ClinicalTrials.gov and World Health Organisation (WHO) registries, and performed a breakdown analysis of studies that were active as of January 31st 2022. We also assessed active drug development projects that had completed one clinical phase but were yet to start the next.

Results:

There was a total of 147 clinical trials registered on the ClinicalTrials.gov website as active during the period of analysis. Of these trials, 91 (62%)were investigating STs, while 56 (38%)focused on DMTs. Approximately 1/3 of the studies (34.7%; 51 trials) were in Phase 1, while over half of the trials were in Phase 2 (50.3%; 74 trials). Only 15% (22 trials) of the studies were in Phase 3, of which only 3 trials were evaluating DMTs. Novel therapeutics (42%)were the most common type of agents being tested across all phases of testing, followed by repurposed agents (34%)and reformulations (20%).

Conclusion:

Despite significant global health constraints, the development of new drug-based therapies for PD continued in 2021. Hopefully with a shift towards a post-pandemic world in which COVID-19 is better managed, we will see an increase in the number of clinical trials focused on drug development for PD. The need for more Phase 3 studies for DMTs remains acute.

Re-Analysis of the STEADY-PD II Trial-Evidence for Slowing the Progression of Parkinson's Disease

BACKGROUND

Recent examination of the STEADY-PD III isradipine clinical trial data concluded that early-stage Parkinson's disease (PD) participants who had longer exposure to isradipine had a significant delay in their need for symptomatic medication, as well as a lower medication burden at the end of the trial. These findings suggest that greater exposure to isradipine might slow disease progression.

OBJECTIVES

To test this hypothesis, the data from the STEADY-PD II isradipine clinical trial, in which an extended-release (ER) formulation of the drug was used, was re-examined.

METHODS

The re-analysis of the STEADY-PD II data was restricted to participants assigned placebo or tolerable isradipine treatment (10 mg isradipine/day or less). The effect of isradipine treatment was assessed by Unified Parkinson's Disease Rating Scale (UPDRS) at the end of the 52-week trial, rather than by last observation carried forward at the beginning of symptomatic therapy.

RESULTS

Participant cohorts were well-matched for baseline disability, initial disease progression, and time to initiation of symptomatic therapy. Participants given 10 mg/day ER isradipine had significantly smaller total and part 3 UPDRS scores at the end of the trial than did the placebo cohort. Post hoc adjustment for symptomatic therapy diminished the statistical significance of these differences. In those participants not taking a monoamine oxidase B inhibitor, the progression in UPDRS scores also was significantly reduced.

CONCLUSIONS

These results are consistent with the recent secondary analysis of the STEADY-PD III clinical trial-suggesting that clinically attainable brain exposure to isradipine may slow early-stage PD progression. © 2021 International Parkinson and Movement Disorder Society.

Waiting for PARIS-A Biological Target in Search of a Drug

A recent breakthrough paper published in Science Translational Medicine has provided compelling evidence that inhibition of Parkin Interacting Substrate (PARIS) may offer clinical researchers an important new therapeutic approach since it shows considerable promise as an important biological target potentially capable of pharmaceutical intervention to slow long term neurodegeneration in patients with Parkinson’s disease (PD). We present several PD-relevant perspectives on this paper that were not discussed in that otherwise entirely scientific narrative. We also outline the some of the work leading up to it, including the massive drug screen that proved necessary to discover a clinically suitable inhibitor of PARIS (Farnesol), as well as relevant PD research within the wider drug class, issues surrounding its future formulation, and next steps in translating this new knowledge into the clinic to evaluate possible long-term PD patient benefits.

Parkinson's Disease Drug Therapies in the Clinical Trial Pipeline: 2020

Background:

The majority of current pharmacological treatments for Parkinson’s disease (PD) were approved for clinical use in the second half of the last century and they only provide symptomatic relief. Derivatives of these therapies continue to be explored in clinical trials, together with potentially disease modifying therapies that can slow, stop or reverse the condition.

Objective:

To provide an overview of the pharmacological therapies— both symptomatic and disease modifying— currently being clinically evaluated for PD, with the goal of creating greater awareness and opportunities for collaboration amongst commercial and academic researchers as well as between the research and patient communities.

Methods:

We conducted a review of clinical trials of drug therapies for PD using trial data obtained from the ClinicalTrials.gov database and performed a breakdown analysis of studies that were active as of January 21, 2020.

Results:

We identified 145 registered and ongoing clinical trials for therapeutics targeting PD, of which 51 were Phase 1 (35% of the total number of trials), 66 were Phase 2 (46% ), and 28 were Phase 3 (19% ). There were 57 trials (39% ) focused on long-term disease modifying therapies, with the remaining 88 trials (61% ) focused on therapies for symptomatic relief. A total of 50 (34% ) trials were testing repurposed therapies.

Conclusion:

There is a broad pipeline of both symptomatic and disease modifying therapies currently being tested in clinical trials for PD.

Parkinson's Disease Drug Therapies in the Clinical Trial Pipeline: 2021 Update

Background:

Despite the COVID-19 pandemic, there has been considerable activity in the clinical development of novel and improved drug-based therapies for the neurodegenerative condition of Parkinson’s disease (PD) during 2020. The agents that were investigated can be divided into “symptomatic” (alleviating the features of the condition) and “disease modifying” (attempting to address the underlying biology of PD) treatments, ST and DMT respectively, with further categorisation possible based on mechanism of action and class of therapy.

Objective:

Our goal in this report was to provide an overview of the pharmacological therapies –both ST and DMT - in clinical trials for PD during 2020–2021, with the aim of creating greater awareness and involvement in the clinical trial process. We also hope to stimulate collaboration amongst commercial and academic researchers as well as between the research and patient communities.

Methods:

We conducted a review of clinical trials of drug therapies for PD using trial data obtained from the ClinicalTrials.gov and World Health Organisation (WHO) registries, and performed a breakdown analysis of studies that were active as of February 18th 2021. We also assessed active drug development projects that had completed one clinical phase but were yet to start the next.

Results:

We identified 142 trials on ClinicalTrials.gov and 14 studies on the WHO registries that met our analysis criteria. Of these 156 trials, 91 were ST and 65 were DMT, Of the 145 trials registered on ClinicalTrials.gov in our 2020 analysis, 45 fell off the list and 42 were added. Despite this change, the balance of ST to DMT; the distribution across phases; the profile of therapeutic categories; and the proportion of repurposed therapies (33.5%); all remained very similar. There are only two DMTs in phase 3, and we identified 33 in-between-phase projects.

Conclusions:

Despite the effects of the coronavirus pandemic, investment and effort in clinical trials for PD appears to remain strong. There has been little change in the profile of the clinical trial landscape even though, over the past year, there has been considerable change to the content of the list.

Drug Repurposing for Parkinson's Disease: The International Linked Clinical Trials experience

The international Linked Clinical Trials (iLCT) program for Parkinson's to date represents one of the most comprehensive drug repurposing programs focused on one disease. Since initial planning in 2010, it has rapidly grown - giving rise to seven completed, and 15 ongoing, clinical trials of 16 agents each aimed at delivering disease modification in Parkinson's disease (PD). In this review, we will provide an overview of the history, structure, process, and progress of the program. We will also present some examples of agents that have been selected and prioritized by the program and subsequently evaluated in clinical trials. Our goal with this review is to provide a template that can be considered across other therapeutic areas.

Efficacy of Nilotinib in Patients With Moderately Advanced Parkinson Disease: A Randomized Clinical Trial

Importance

There is a critical need for careful and independent validation of reported symptomatic efficacy and dopaminergic biomarker changes induced by nilotinib in Parkinson disease (PD).

Objectives

To assess safety and tolerability of nilotinib in participants with moderately advanced PD. Secondary and exploratory objectives were to assess its affect on PD disability, pharmacokinetics, cerebrospinal fluid (CSF) penetration, and biomarkers.

Design, Setting, and Participants

This was a 6-month, multicenter, randomized parallel-group, double-blind, placebo-controlled trial. Recruitment was from November 20, 2017, to December 28, 2018, and follow-up ended on September 9, 2019. The study was conducted at 25 US sites. The study approached 173 patients, of whom 48 declined, 125 were screened, and 76 who received a stable regimen of PD medications were enrolled (39% screen failure).

Interventions

Participants were randomized 1:1:1 to placebo, 150-mg nilotinib, or 300-mg nilotinib once daily orally for 6 months, followed by 2-month off-drug evaluation.

Main Outcomes and Measures

The primary outcomes were safety and tolerability. The tolerability end point was defined as the ability to complete the study while receiving the assigned dose. An active arm was considered tolerable if the percentage of participants meeting the tolerability end point for that group was not significantly lower than the percentage observed in the placebo group. Secondary outcomes included change in PD disability (Movement Disorder Society Unified Parkinson's Disease Rating Scale [MDS-UPDRS], Part II OFF/ON). Exploratory outcomes included serum and CSF pharmacokinetic profile, and CSF dopaminergic biomarkers.

Results

At baseline, mean (SD) participants' age was 64.6 (7.5) years, 52 were male (68%), mean (SD) disease duration was 9.9 years (4.7), MDS-UPDRS Part 1-3 OFF score was 66.4 (19.3), ON score was 48.4 (16.2), and Montreal Cognitive Assessment score was 27.1 (2.2). The number of participants who completed the study receiving the assigned dose were 21 (84%), 19 (76%), and 20 (77%) in the placebo, 150-mg, and 300-mg arms, respectively. Both active doses had acceptable safety profile. The most common reasons for drug suspension were asymptomatic, dose-dependent elevations of amylase, and/or lipase. Nilotinib, 150 mg and 300 mg, exhibited worse MDS-UPDRS-3 ON scores compared with placebo, achieving significance for nilotinib, 300 mg, at month 1 (P < .01). There was no difference in the change of MDS-UPDRS-3 OFF from baseline to 6 months between groups (P = .17). Cerebrospinal fluid/serum ratio of nilotinib concentration was 0.2% to 0.3%. There was no evidence of treatment-related alteration of dopamine metabolites in the CSF.

Conclusions and Relevance

While we demonstrated acceptable safety and tolerability of nilotinib in our cohort, the low CSF exposure and lack of biomarkers effect combined with the efficacy data trending in the negative direction indicate that nilotinib should not be further tested in PD.

Trial Registration

ClinicalTrials.gov Identifier: NCT03205488.

The Parkinson's Disease Comprehensive Response (PDCORE): a composite approach integrating three standard outcome measures

There is an increasing need for improved endpoints to assess clinical trial effects in Parkinson's disease. We propose the Parkinson's Disease Comprehensive Response as a novel weighted composite endpoint integrating changes measured in three established Parkinson's outcomes, including: OFF state Movement Disorder Society Unified Parkinson's Disease Rating Scale Motor Examination scores; Motor Experiences of Daily Living scores; and total good-quality ON time per day. The data source for the initial development of the composite described herein was a recent Phase II trial of glial cell line-derived neurotrophic factor. A wide range of clinically derived relative weights was assessed to normalize for differentially scoring base rates with each endpoint component. The Parkinson's disease comprehensive response, in contrast to examining practically defined OFF state Unified Parkinson's Disease Rating Scale Motor Examination scores alone, showed stability over 40 weeks in placebo patients, and all 432 analyses in this permutation exercise yielded significant differences in favour of glial cell line-derived neurotrophic factor. The findings were consistent with results obtained employing three different global statistical test methodologies and with patterns of intra-patient change. Based on our detailed analyses, we conclude it worth prospectively evaluating the clinical utility, validity and regulatory feasibility of using clinically supported final Parkinson's disease comprehensive response formulas (for both the Unified Parkinson's Disease Rating Scale-based and Movement Disorders Society-Unified Parkinson's Disease Rating Scale-based versions) in future disease-modifying Parkinson's trials. Whilst the data source employed in the initial development of this weighted composite score is from a recent Phase II trial of glial cell line-derived neurotrophic factor, we wish to stress that the results are not described to provide post hoc evidence of the efficacy of glial cell line-derived neurotrophic factor but rather are presented to further the debate of how current regulatory approved rating scales may be combined to address some of the recognized limitations of using individual scales in isolation.

GDNF and Parkinson's Disease: Where Next? A Summary from a Recent Workshop

The concept of repairing the brain with growth factors has been pursued for many years in a variety of neurodegenerative diseases including primarily Parkinson's disease (PD) using glial cell line-derived neurotrophic factor (GDNF). This neurotrophic factor was discovered in 1993 and shown to have selective effects on promoting survival and regeneration of certain populations of neurons including the dopaminergic nigrostriatal pathway. These observations led to a series of clinical trials in PD patients including using infusions or gene delivery of GDNF or the related growth factor, neurturin (NRTN). Initial studies, some of which were open label, suggested that this approach could be of value in PD when the agent was injected into the putamen rather than the cerebral ventricles. In subsequent double-blind, placebo-controlled trials, the most recent reporting in 2019, treatment with GDNF did not achieve its primary end point. As a result, there has been uncertainty as to whether GDNF (and by extrapolation, related GDNF family neurotrophic factors) has merit in the future treatment of PD. To critically appraise the existing work and its future, a special workshop was held to discuss and debate this issue. This paper is a summary of that meeting with recommendations on whether there is a future for this therapeutic approach and also what any future PD trial involving GDNF and other GDNF family neurotrophic factors should consider in its design.

Novel approaches to counter protein aggregation pathology in Parkinson's disease

The primary neuropathological characteristics of the Parkinsonian brain are the loss of nigral dopamine neurons and the aggregation of alpha synuclein protein. Efforts to development potentially disease-modifying treatments have largely focused on correcting these aspects of the condition. In the last decade treatments targeting protein aggregation have entered the clinical pipeline. In this chapter we provide an overview of ongoing clinical trial programs for different therapies attempting to reduce protein aggregation pathology in Parkinson's disease. We will also briefly consider various novel approaches being proposed-and being developed preclinically-to inhibit/reduce aggregated protein pathology in Parkinson's.

Parkinson Matters

Recent epidemiological observations have drawn attention to the rapid rise in the burden caused by Parkinson's disease over the past years, emphasizing that Parkinson's disease is a matter of serious concern for our future generations. A recent report by Public Health England corroborates this message, by providing new insight on trends in deaths associated with neurological diseases in England between 2001 to 2014. The report indicates that mortality associated with Parkinson's disease and related disorders increased substantially between 2001 and 2014. This trend is partially explained by increased longevity in the population. However, it is possible that changes in exposure to risk factors, recent improvements in multidisciplinary care (leading to prolonged survival), and improved diagnostic awareness or improved registration also influenced the observed trend. Furthermore, patients with Parkinson's disease and related disorders were found to die at an advanced age, and the majority die in a care home or hospital, despite a preponderant preference for many patients and their families to spend their last days at home. To combat these concerning observations, future efforts should be focused on providing resources for vulnerable elderly Parkinson patients, avoiding unplanned hospital admissions and out-of-home deaths as much as possible. Possible solutions include a community-based network of specifically trained allied health therapists, personal case managers for Parkinson patients, dedicated Parkinson nursing homes, and improved centralised support services from university clinics to regional community hospitals aimed at facilitating optimal wide-scale care delivery.

Nilotinib - Differentiating the Hope from the Hype

We discuss a report in the current issue on clinical and biochemical findings from a safety trial using the cAbl tyrosine kinase inhibitor Nilotinib (150 mg or 300 mg given daily for 24 weeks) in a small group of patients with either advanced Parkinson’s disease or Dementia with Lewy Bodies. Despite some side effects (one serious), the authors claim that Nilotinib, which is normally used at much higher doses for treating leukemia, is safe and tolerated. Furthermore, they report a possible benefit on motor and cognitive outcomes. We debate the safety of Nilotinib and the reported efficacy signals. We emphasize that due to the small sample size, and lack of a control group, it is impossible to rule out a placebo effect. We briefly discuss a range of aspects surrounding the current and possible future use of this cAbl inhibitor in patients with alpha-synucleinopathy, and what must now be done to obtain definitive information about its safety and efficacy in this population of patients.

Cellular and molecular aspects of Goodpasture syndrome

Goodpasture syndrome, a rare human autoimmune disorder, is characterized by the presence of pathogenic autoantibodies that react with the components of the glomerular basement membrane. The clinical condition of the Goodpasture syndrome is characterized by an acute necrotizing glomerulonephritis, often with accompanying pulmonary hemorrhage. Notably, the Goodpasture antigen has been localized to the noncollagenous domain of the alpha3 chain of type IV collagen. Additionally, human leukocyte antigen-DR2, and to a lesser extent human leukocyte antigen-DR4, have been identified as important restriction elements. The role of T cells in Goodpasture syndrome is indicated by the highly restricted specificity of the antibody response and the strong major histocompatibility complex class II association. In this review article, we briefly describe the latest views on the molecular and cellular themes of Goodpasture syndrome.

A close link between Fas, p53 and Apaf-1 in chronic myeloid leukemia

In chronic myeloid leukemia (CML) proliferation is increased and resistance to apoptosis has been proposed as a mechanism accounting for myeloid cell expansion. There is still controversy on whether apoptosis plays an important role in the regulation of myelopoiesis. This study aims to investigate whether apoptosis-related proteins play a role in the evolution of CML and to identify, the relationship between Fas, p53 and apoptosis protease activating factor (Apaf-1) in CML. We found increased p53 and Apaf-1 messenger ribonucleic acid (mRNA) in patients with CML. However, one patient, who had a p53 point mutation, showed a massive elevation of p53 mRNA during blast crisis yet, conversely, a considerable reduction in Apaf-1 mRNA and Fas mRNA. Our results show an in-vivo linkage between Fas, p53 and Apaf-1 transcription regulation. This suggests that key genes involved in apoptosis are also involved in CML disease progression.

Pharmacotherapy of fungal eye infections

Fungal eye infections are rare. Trauma associated with contamination by vegetative material, contact lens wear and long term corticosteroid use are common risk factors. The aims of treatment are to preserve visual function, which depends on the rapid diagnosis and efficient administration of appropriate antifungal therapy. This necessitates a clinical suspicion of fungal aetiology and the taking of appropriate smears and cultures as early as possible to identify the fungal organism. Currently there are three main classes of drugs available for use in fungal eye infections: polyenes, azoles as derivatives of imidazoles, and 5-fluorocytosine. Of the polyenes, amphotericin B, natamycin and nystatin are of clinical ophthalmic use. Based on better pharmacokinetic profiles and spectra of antifungal activity, the triazoles are the agents of choice. Successful treatment of fungal keratitis depends on early initiation of specific therapy consisting of topically-applied antifungal agents since topical administration is most likely to provide the best opportunity for achieving therapeutic corneal levels. Hence, the molecular weight of the various antifungal agents is of importance since it influences their ability to penetrate the corneal epithelium. Systemic administration may be necessary for resistant fungal ulcers. For fungal endophthalmitis, to preserve visual function and eliminate the fungal pathogen, topical, systemic and possibly intraocular antifungal therapy is used, although some do not recommend use of systemic agents for exogenous endophthalmitis.

Role of aprotinin in the management of patients during and after cardiac surgery

Management of patients undergoing cardiac surgery has evolved in recent years as more is understood about the physiological changes and responses that occur during and after cardiopulmonary bypass (CPB). In particular, our understanding of the mechanisms involved in haemostasis and in the inflammatory response to bypass surgery, has allowed significant refinements in patient management. Improvements in the pharmacological conservation of blood loss have been striking, particularly with the development of the serine protease inhibitor, aprotinin (Trasylol, Bayer). Aprotinin represents a significant improvement, especially for patients at high risk, since it reduces the need for allogeneic and (sometimes scarce) blood products. However, in view of its cost, making an appropriate selection of patients most at risk of serious blood loss is a major consideration in the use of aprotinin. While its mechanisms of action are not well understood, the use of aprotinin also appears to reduce inflammatory response to CPB.

Prospective development of a cardiac surgical registry

Interest has recently been expressed in developing an Australian adult cardiac surgical registry. Complete national registries of adult cardiac surgery have already been established in many European countries, the USA, Canada and elsewhere. Participating centres contributing to a national registry benefit by being able to benchmark themselves against norms for their particular country. A risk-adjusted database can help surgeons advise their patients of the chances of a good operative outcome. For a surgeon or a surgical unit, the only way to obtain a relevant risk model is to use their own data, and data from units in their particular country. It is also useful to have comparative data from other national registries to compare one's own country with international benchmarks. Since 1996, the European Cardiac Surgical Registry (ECSUR) has put considerable effort into producing unified datasets, harmonised with each other for worldwide use. In 1997, ECSUR launched a minimum cardiac surgical dataset. The worldwide launch of the full international adult cardiac surgical dataset is scheduled for July/August 2000. This dataset would be highly useful for application in Australia. The ECSUR organisation has the capability to analyse data from other countries and could perform this for Australia if requested. However, a better approach would be a national centre in Australia. Funding for national registries around the world has been obtained from Ministries of Health, participating surgical centres, and surgical software vendors. If an Australian national registry is indeed established it will find a ready-made, highly appropriate international cardiac surgical dataset sponsored by ECSUR and the Society of Thoracic Surgeons waiting for adoption by Australia.

The development of an international surgical registry: the ECSUR project. The European Cardiac Surgical Registry

OBJECTIVES

Cardiac surgery is the first of any therapeutic discipline to attempt to establish a major international registry on a patient-by-patient basis. Being the first necessarily imposes a challenge since no rules or guidelines exist. Possibilities and boundaries must be identified.

METHODS

The EACTS database committee established ECSUR (The European Cardiac SUrgical Registry) with the aim of collecting patient-by-patient information from centres across Europe. It was decided to collect patient data in three areas; adult cardiac surgery, paediatric cardiac surgery and thoracic surgery. Currently, these three areas are in different stages of development, with multinational data collection now having already commenced in adult cardiac surgery.

RESULTS

After just over a year of data collection ECSUR has now received data from 98 centres in 30 countries, encompassing approximately 100,000 patients. Three national cardiac surgical registries currently send their data to ECSUR, and agreement has been reached with three other countries for prospective data sharing during 1999.

CONCLUSION

This paper describes how ECSUR was established, the on-going status of the project, and how the project has now developed a global perspective through a joint European and US initiative to undertake international dataset unification for surgeons worldwide, by the definition of core adult cardiac, paediatric cardiac and thoracic surgical datasets.

Genetic variation in the COL6A1 region is associated with congenital heart defects in trisomy 21 (Down's syndrome)

Genetic variation in the COL6A1-COL6A2 gene cluster on chromosome 21 was studied in 113 controls and 58 European families (including control and family subgroups of British/Irish origin) having a child with trisomy 21. There were statistically significant differences among subgroups of trisomic children with and without congenital heart defects (CHD) in distributions of definitive, 3-RFLP haplotype classes received from their nondisjoining and disjoining parents. Haplotypes received by trisomic children with CHD from their disjoining parents were not a random sample of controls' haplotypes. Analysis of parental single-RFLP genotypes and linkage disequilibrium patterns confirmed this parent subgroup differed from a random sample of controls. There were no significant differences in parent subgroup genotype distribution at any of nine control loci distributed along chromosome 21q. This sample showed an association between genetic variation in the COL6A1 gene region and congenital heart defects in trisomy 21.

Unusual genotypes in the COL6A1 gene in parents of children with trisomy 21 and major congenital heart defects

Collagen type VI is a candidate for a role in the pathogenesis of congenital heart defects (CHD) in Down's syndrome. Three restriction fragment length polymorphisms of the COL6A1 gene were used to determine COL6A1 genotypes in 50 families of affected children with trisomy 21 (29 with congenital heart defects and 21 without) and 37 unrelated volunteers. We found seven unusual genotypes in the parents of affected children with Down's syndrome, five being unique to the parents of children with trisomy 21 and CHD. There were no unusual genotypes associated with other chromosome 21 loci. No single COL6A1 genotype was associated with CHD. Thus, the unusual genotypes unique to parents of affected children suggest that genetic variation in the COL6A1 gene region contributes to the pathogenesis of CHD in Down's syndrome.

Meiotic crossing-over in nondisjoined chromosomes of children with trisomy 21 and a congenital heart defect

We have used DNA polymorphisms to study meiotic crossovers of chromosome 21q in 27 nuclear families. Each family had a child with Down syndrome and a congenital heart defect. Twenty DNA polymorphisms on chromosome 21 were used to determine parental and meiotic origin of nondisjunction and to identify crossovers. Twenty-four cases were of maternal origin, and three were of paternal origin. Twenty-two unequivocal crossover events were identified. Sixteen crossovers were observed in 22 chromosome pairs nondisjoining at the second meiotic division. Fifty percent of crossover events in MI nondisjunction are detectable by molecular genetic means. Thus, the results suggest that, in this sample, each nondisjoined chromosome 21 pair has been involved in at least one crossover event.

Congenital heart disease in CHARGE association

This study reviews the spectrum of congenital heart disease and associated anomalies in 59 patients with the CHARGE association. We have analyzed our clinical experience in managing the cardiovascular anomalies and have reviewed outcome and risk factors for mortality. This study also highlights problems of cardiac management in children born with multiple system involvement. Twenty patients have died; actuarial survival was 78% at 1 year and 60% at 10 years. In only four of the nonsurvivors could their demise be ascribed to their underlying congenital heart disease. We found the outlook for survival was poor if more than one of the following three features were present; cyanotic cardiac lesions, bilateral posterior choanal atresia, or tracheoesophageal fistula. However, mortality was largely due not to the structural heart or choanal abnormalities, but instead reflected the underlying pharyngeal and laryngeal incoordination which resulted in aspiration of secretions. Furthermore, outcome is likely to be improved if collaboration between specialist surgical teams allows necessary procedures to be performed using the minimum of anesthetics. Examination of both the short- and long-term management of these children has stressed the importance of a multidisciplinary approach to their care. The pattern of cardiac defects was not random; lesions within the Fallot spectrum accounted for 33% of their congenital heart disease. Atrioventricular septal defects were also overrepresented. Not all cardiovascular defects could be explained by hypothesizing a neural crest etiology.

CHARGE and esophageal atresia

CHARGE association was diagnosed in 61 infants, 20 of whom died, mainly during the first 2 years of life. Esophageal atresia and/or tracheoesophageal fistula were present in 10 neonates. Axial skeletal anomalies occurred in 7 of the 10, but none had preaxial limb defects typical of the VATER association. All had major cardiac anomalies, predominantly tetralogy of Fallot. The majority of patients had primary repair of the esophagus. The postoperative course was stormy in all patients, with a high incidence of complications and 70% died. The recognition of features of the CHARGE association is important because it has major prognostic and therapeutic implications.

Morbid anatomy in neonates with Ebstein's anomaly of the tricuspid valve: pathophysiologic and clinical implications

The hearts of six neonates with Ebstein's anomaly of the tricuspid valve who died in the 1st month of life were compared with hearts of six age- and size-matched control neonates. All six hearts had morphologically severe disease with gross right atrial dilation and marked apical displacement of the tricuspid valve. All had a secundum atrial septal defect and four had additional cardiac lesions (pulmonary atresia in two, ventricular septal defect in two). There was significant thinning of the right ventricular free wall distal to the tricuspid valve (3 +/- 0.2 mm vs. control 4.2 +/- 0.2, p less than 0.01) and right ventricular fiber diameter was reduced (7.2 +/- 0.3 microns vs. control 11.4 +/- 0.6, p less than 0.001). The fibrous tissue content of both right and left ventricular free walls was increased (right, 29.3 +/- 2.6% vs. control 8.7 +/- 1.1, p less than 0.001; left, 23.2 +/- 1.5% vs. control 8.5 +/- 0.7%, p less than 0.001). Although the right ventricular abnormalities might be explained by hemodynamic stress in utero, abnormalities of the left ventricular free wall suggest that either genetic or nonhemodynamic environmental factors are involved in the morphogenesis of this condition. Increased right and left ventricular fibrosis may contribute to the poor early outcome in this group and may predispose to late complications, such as subnormal exercise performance, hemodynamic deterioration or late sudden death that may occur in patients with Ebstein's anomaly who survive the neonatal period.

Outcome in neonates with Ebstein's anomaly

The presentation and outcome of 50 patients with neonatal Ebstein's anomaly seen from 1961 to 1990 were reviewed. The majority (88%) presented in the 1st 3 days of life; cyanosis (80%) was the most common presenting feature. Associated defects, present in 27 infants (54%), included pulmonary stenosis in 11 and atresia in 7. Nine patients (18%) died in the neonatal period; there were 15 late deaths (due to hemodynamic deterioration in 9, sudden death in 5 and a noncardiac cause in 1) at a mean age of 4.5 years (range 4 months to 19 years). Actuarial survival at 10 years was 61%. A new echocardiographic grade (1 to 4 in order of increasing severity of the defect) was devised with use of the ratio of the area of the right atrium and atrialized right ventricle to the area of the functional right ventricle and left heart chambers. Cardiac death occurred in 0 of 4 infants with grade 1, 1 (10%) of 10 with grade 2, 4 (44%) of 9 with grade 3 and 5 (100%) of 5 with grade 4. In a multivariate analysis of clinical and investigational features at presentation, echocardiographic grade of severity was the best independent predictor of death. Neonates with Ebstein's anomaly have a high early mortality rate and those surviving the 1st month of life remain at high risk of late hemodynamic deterioration or sudden death. Echocardiographic grading of severity of the defect permits prognostic stratification.

Relapse following goniotomy for congenital glaucoma due to trabecular dysgenesis

Three hundred and thirty-five eyes of 210 patients with congenital glaucoma due to trabecular dysgenesis were treated by goniotomy as the primary procedure in infancy. In 313 eyes (93.5%) glaucoma was controlled at one year following surgery. Using Kaplan Meier actuarial survival analysis we found that eyes controlled in infancy by one or more goniotomies are at risk of relapse of glaucoma for at least 15 years although 93% of eyes are still controlled five years after the initial surgery. Patients whose symptoms of congenital glaucoma presented at birth were more likely to relapse than those whose symptoms developed in the first few months of life. Eyes requiring multiple goniotomies in infancy were more likely to relapse than those controlled by a single procedure.

Early and late arrhythmias after the Fontan operation: predisposing factors and clinical consequences

OBJECTIVE

To study the incidence, predisposing factors, and clinical significance of arrhythmias early and late after the Fontan operation for congenital heart disease.

PATIENTS AND METHODS

All 104 consecutive patients undergoing Fontan repair from 1975 to 1988 were studied retrospectively. Hospital records were reviewed for perioperative arrhythmia. Clinical information and annual electrocardiograms were available for all 78 hospital survivors during a follow up of up to 13 years (mean 3.7 years). Ambulatory electrocardiographic monitoring was performed in 67 patients (81%).

RESULTS

Eleven patients (10.6%) developed a perioperative tachycardia (eight, atrial flutter; three, His bundle tachycardia). Multivariate analysis showed that raised preoperative mean pulmonary artery pressure and low aortic saturation were significant risk factors for the development of atrial flutter (r2 = 0.32, p = 0.0001) but not for His bundle tachycardia. Despite intensive medical treatment 10 of these 11 patients died. At the last visit 72 (92%) of the 78 patients were in sinus rhythm on their standard 12 lead electrocardiogram. Junctional rhythm was present in three patients, two patients had atrial flutter, and one had a paced rhythm. Ambulatory monitoring did not show important bradycardia or ventricular arrhythmias. Actuarial survival free of supraventricular arrhythmia was 82% at eight years after operation. Multivariate analysis identified older age, increased right atrial size, and raised mean preoperative pulmonary artery pressure as risk factors for arrhythmia during intermediate follow-up (r2 = 0.46, p less than 0.001). Late tachycardias, in contrast to those occurring in the perioperative period, were not associated with an increased mortality.

CONCLUSIONS

Except for his bundle tachycardia in the perioperative period, early and late arrhythmias after a Fontan operation seem to be a consequence of adverse preoperative and postoperative haemodynamic function. The perioperative outcome is therefore poor even when the patient can be restored to sinus rhythm. Medical and surgical modifications to improve the haemodynamic disturbances associated with arrhythmias are therefore indicated.

Incidence and management of airway problems in the CHARGE Association

The airway problems associated with anaesthesia in patients with the CHARGE Association have been underreported. We undertook a retrospective review of 50 cases, of which anaesthetic records were available for 37 patients. Apart from choanal atresia and cleft lip and palate, 56% of patients has some other upper airway abnormality. There appeared to be greater difficulty in tracheal intubation with increase in age in four patients. The incidence and management of airway abnormalities are discussed.

Microdeletions within 22q11 associated with sporadic and familial DiGeorge syndrome

DiGeorge syndrome (DGS) is a developmental field defect of the third and fourth pharyngeal pouches. It is associated with deletion of 22q11 in 11% of cases. Molecular genetic analysis with probes from 22q11-pter reveals that a subset of markers is hemizygous in DGS patients with normal karyotypes. There is no apparent difference in the phenotype or the severity of the disorder between patients with the smallest detectable submicroscopic deletion and those with the largest cytogenetically visible abnormality. A microdeletion was found in a mildly affected child and in the severely affected child of a mildly affected father. Dysmorphology, especially cardiac outflow tract anomalies, resulting from 22q11 deletion may be more common than currently realized since chromosomes are unlikely to be checked if the complete spectrum of DGS is not present. Antenatal diagnosis, through detection of hemizygosity at 22q11, will be a possibility for mildly affected parents unwilling to risk the birth of a severely affected child.

Perioperative monitoring of total body water by bio-electrical impedance in children undergoing open heart surgery

Knowledge of the changes in total body water (TBW) following cardiac surgery (OHS) in children would be of value in fluid therapy and in researching the causes and management of capillary leak. We have validated a bioelectrical impedance technique (BEI) for non-invasive estimation of TBW in children after OHS. We report the use of this method in a longitudinal study. Twenty patients (mean age 4.7 years +/- 3.5 (SD), mean weight (WT) 16.2 kg +/- 1 kg) undergoing a variety of complex OHS procedures were studied from 1 day preoperatively to 4 days postoperatively. Anaesthetic and basic bypass (CPB) techniques were uniform. Six patients underwent CPB at less than 20 degrees C, 10 at 20 degrees - 25 degrees C and 4 at 26 degrees - 33 degrees C. TBW (BEI), core (ctemp) and peripheral (ptemp) temperatures and fluid balance (TFB) were recorded at frequent intervals. TBW (by BEI) rose (P less than 0.001) following CPB in all patients from 62% +/- 9% (SD) body weight preoperatively to 73% +/- 13% in the ICU (an increase of 11% +/- 5%). TBW remained significantly elevated until the 3rd postoperative day. Multivariate analysis (MVA) confirmed that TBW was significantly related to TFB, but not to ctemp or ptemp. MVA also revealed smaller patient size (height and weight), younger age and longer CPB time as incremental risk factors for the rise in TBW.

CONCLUSIONS

(1) BEI permits the non-invasive study of TBW in children after OHS, when TBW variation may be considerable. (2) The smaller the child and the longer the CPB, the greater the rise in TBW. (3) The technique should be a valuable tool in researching the major water fluxes associated with CPB in children.

Neural cell adhesion molecule (N-CAM) in fetal and mature human heart

Using Northern blot analysis and immunoblotting techniques we report for the first time, that the neural cell adhesion molecule, N-CAM, is expressed in human heart. We found several different N-CAM transcripts in human fetal (13-17 weeks gestation) and mature heart (left ventricle from a 5-year-old child). Northern blotting showed that a 5.2 kb transcript was the most abundant and progressively increased with age, both in fetal and mature heart. These transcripts may correspond with the different protein isoforms shown by immunoblotting. We also confirmed the presence of N-CAM in fetal and mature myocytes by immunohistochemical techniques, using a monoclonal antibody to human N-CAM. Results demonstrated that N-CAM is mainly confined to the myocyte cell surface.

The eye in the CHARGE association

CHARGE association includes patients with at least four features prefixed by the letters of the mnemonic: Coloboma, Heart defects, Atresia of the choanae, Retarded growth and development, Genital hypoplasia, Ear anomalies and/or hearing loss. Many also have facial palsy. We report a series identified by collaboration within one centre of all specialties concerned in the management of the CHARGE association. Ocular abnormalities were found in 44 out of 50 patients with the CHARGE association. Of these, 41 had 'typical' colobomata. The majority had retinochoroidal colobomata with optic nerve involvement, but only 13 patients had an iris defect. Two patients had atypical iris colobomata with normal fundi. Additional features were microphthalmos in 21 patients, optic nerve hypoplasia in four, nystagmus in 12, and a vertical disorder of eye movement in four of the 22 cases with facial palsy. We report an incidence of coloboma in the CHARGE association of 86% (43/50) compared with a previous cumulative reported incidence of 66% (112/170). We believe that there may have been previous underdiagnosis of colobomata in children with multiple congenital abnormalities.

Congenital heart anomalies in patients with clefts of the lip and/or palate

The nature and severity of congenital heart disease in 78 patients who presented with clefts of the lip and/or palate is reported. The prevalence of bilateral cleft lip and palate in patients with heart lesions was much higher than in cleft patients with normal hearts. Cardiac defects were predominantly conotruncal. Tetralogy of Fallot was present in 24 percent of patients; the prevalence of transposition, atrioventricular septal defect, and truncus arteriosus was also disproportionately high. Patients with conotruncal defects had a greater prevalence of either unilateral or bilateral cleft lip and palate. Most patients with congenital heart disease and clefting had additional abnormalities. Anomalies of other systems were found to be present in 87 percent of patients.

The natural and "unnatural" history of congenitally corrected transposition

The data available on 111 patients with congenitally corrected transposition and 2 adequate ventricles managed over the 20-year period to 1988 were reviewed retrospectively. The ages of survivors ranged from 1 to 58 years (median 20) and all but 10 had additional anatomic abnormalities. Tricuspid valve abnormalities were more prevalent in patients symptomatic with heart failure (26 of 43 patients) than those whose main problem was cyanosis (11 of 52 patients); all dysplastic or Ebstein valves were at least moderately incompetent. Intracardiac repair of the lesion was attempted in 51 patients with 11 early deaths; in multivariate models, the risk factors for early death or a bad early outcome or poor result 6 months later related to poor preoperative symptomatic status (especially from heart failure), impaired right ventricular function, heart block and younger age at surgery. Patients with more than mild preoperative tricuspid regurgitation whose valves were not replaced did very poorly. Thus, patients symptomatic from heart failure should probably be repaired early in the natural history of the disease, before the systemic right ventricles dilate. By contrast, the course of patients who were predominantly cyanosed was more stable in early childhood and their surgical outcome was less compromised by poor preoperative symptomatic status; their intracardiac repair can probably be delayed until symptoms become unacceptable.

Exercise responses in patients with congenital heart disease after Fontan repair: patterns and determinants of performance

After a Fontan repair for congenital heart disease, 42 patients underwent graded supine bicycle exercise tests at levels relevant to normal daily activities. Results were compared with those of 28 age-matched normal control subjects. At rest, the cardiac index, stroke index and systolic blood pressure were comparable in both groups, but increases with exercise were smaller in the patients with a Fontan circulation. The heart rate at rest was higher in the Fontan group, but this difference disappeared as soon as exercise started. To determine whether there are limitations intrinsic to the Fontan circulation at these levels of exercise, the 10 best performers were compared with 10 age-matched control subjects; no differences were found in cardiac index, stroke index, heart rate or blood pressure at any exercise level. Analysis of the determinants of cardiac output showed that at the other end of the spectrum poor performance after a Fontan operation did not result from inadequate levels of heart rate, but from an inability to increase or maintain stroke volume. Multivariate analysis demonstrated that impairment of ventricular contractility, only when severe, predicted limited performance. There was no evidence of increased afterload, particularly in the poor performers. Therefore, ventricular filling, which is determined primarily by the pulmonary vascular bed, appears to be a major determinant of functional result after a Fontan repair.

Endothelin-1 mRNA is widely expressed in porcine and human tissues

Endothelin-1 (ET-1) is a potent vasoconstrictor peptide isolated from porcine endothelial cells. We have previously demonstrated widespread binding sites for ET-1 in blood vessels, heart, kidney, adrenal, lung, and brain in a distribution that paralleled that of endothelial cells. To determine whether these cells are capable of synthesizing ET-1 in close proximity to its binding sites, amplification of cDNA using the polymerase chain reaction and in situ hybridization were used to study the distribution of ET-1 mRNA. We have found widespread transcription of ET-1 mRNA in human and porcine tissues. The identity of the transcripts was confirmed by prediction of restriction fragment lengths or sequencing. In situ hybridization in the kidney showed that the regional expression of these transcripts is localized, probably to small blood vessels, but the failure to visualize ET-1 mRNA in the capillaries may reflect absence of expression or insufficient sensitivity of the technique. These results should permit investigation of the role of ET-1 as a local factor in vascular pathophysiology.

Normal values for noninvasive estimation of left ventricular contractile state and afterload in children

The outcome and suitability for therapeutic interventions in children with congenital heart disease depend frequently on left ventricular function. Congenital heart disease is characterized by changes in loading conditions, making it difficult to assess ventricular contractility using conventional load-dependent indexes. Two-dimensional and M-mode echocardiography and arterial blood pressure were used to study left ventricular morphometrics and contractility in 44 normal children, aged 2 to 12 years. Left ventricular end-systolic and end-diastolic length, diameter, wall thickness, volume and mass all showed linear increases with body surface area (p less than 0.001 in all). Shortening and ejection fractions, velocity of circumferential fiber shortening, morphometric ratios and endocardial meridional and circumferential stress (mean 46 and 115 g/cm2, respectively) all remained constant. A load-independent measure of the normal resting left ventricular contractile state was determined by relating the rate-corrected velocity of circumferential fiber shortening to end-systolic endocardial meridional and circumferential stress; there was an inverse linear correlation (r = -0.641 and -0.557 respectively, p less than 0.001). These data provide a quantitative basis for assessment of myocardial hypertrophy, afterload and contractile state in childhood.

Who's in CHARGE? Multidisciplinary management of patients with CHARGE association

Clinical experience of 50 patients with the CHARGE association is reviewed and problems with management of children born with multiple system involvement is highlighted. It was found that the outlook for survival was poor if more than one of the following three features was present: cyanotic cardiac lesions, bilateral posterior choanal atresia, or tracheo-oesophageal fistula. Mortality was largely due not to the structural heart defects or choanal abnormalities, but reflected underlying pharyngeal and laryngeal incoordination, which resulted in aspiration of secretions. Outcome is likely to be improved if collaboration between specialist surgical teams allows necessary procedures to be performed using the minimum number of anaesthetics. Examination of both the short and long term management of these children has stressed the importance of a multidisciplinary approach to their care.

Impact of Fontan operation on left ventricular size and contractility in tricuspid atresia

Left ventricular dimensions and contractility were determined by echocardiography in 33 patients with tricuspid atresia in 1985 and again in 1988. Eight patients remained palliated throughout the 3-year period; neither the left ventricular end-diastolic diameter (153 +/- 15% of normal vs. 157 +/- 19%, p = NS) nor a load-independent index of contractility (rate-corrected velocity of shortening [VCFc]/end-systolic meridional stress [ESSM]) changed. Eleven patients underwent a Fontan operation during the study and were reevaluated at least 6 months after surgery; left ventricular dimension decreased (130 +/- 15% vs. 114 +/- 19%, p less than 0.001), and the contractility index VCFc/ESSM improved (p less than 0.05). Fourteen patients had undergone a Fontan operation 0.9-9.5 years (mean, 4.2 years) before initial examination in 1985. Over the 3-year period, left ventricular dimensions did not change (121 +/- 17% vs. 118 +/- 11%, p = NS), but the contractility index showed significant improvement (p less than 0.01). Eight additional patients were studied just before and after a Fontan operation to examine the early effects of surgery. Left ventricular dimensions decreased from 130 +/- 14% to 100 +/- 13% by 10 days p less than 0.001) with no further change at 2 months. An inappropriate degree of ventricular hypertrophy was observed in only the early postoperative period. Successful Fontan repair results in rapid reduction of left ventricular size, followed by regression of hypertrophy to a normal mass-to-volume ratio. Operating at more favorable dimensions and loading conditions results in an early increase in left ventricular contractility, which further improves in the medium term follow-up.

CHARGE association in two monozygous triplets

In an unusual set of triplets, two monozygous girls presented with CHARGE association. Dissimilar surgical management of identical cardiovascular lesions has resulted in a disparate effect on their clinical state. Their case poses interesting questions concerning how CHARGE association may develop.

Long-term results of homograft valves in extracardiac conduits

Between 1971 and 1986, 335 patients received various extracardiac valved conduits between one of the heart chambers and the pulmonary arteries. The group of patients who received aortic homograft conduits and survived the operation were analysed in detail. The age varied between 9 days and 18 years (mean 7.1 +/- 0.7 years), weight 2.4 kg-63.5 kg (mean 17.8 +/- 10.8 kg). The diameter of the conduit used was 10-30 mm (mean 20.8 mm). Multivariate analysis revealed a highly significant model (P less than 0.005) which showed that the time interval between harvesting and use of the homograft (P less than 0.02) and the earlier date of operation (P less than 0.05) were the major risk factors for obstruction. Homografts used within 3 weeks of harvesting had freedom from obstruction of 79% at 8 years; homografts used between 3-6 weeks had freedom from obstruction of only 55% at 8 years. Homografts used alone performed significantly better than those extended with woven Dacron tubes. At 10 years, 93% of homografts used alone were free of obstruction compared to 52% of homografts extended with a Dacron tube. We conclude that aortic homografts used within 3 weeks of harvesting provide a reasonably durable conduit for a period of 12 years. Longer storage, and extension of the homograft with a woven Dacron tube should be avoided.

The role of the priming fluid in the metabolic response to cardiopulmonary bypass in children of less than 15 kg body weight undergoing open-heart surgery

The major metabolic response to open-heart surgery using cardiopulmonary bypass has been shown in adults to be modified by the components of the pump priming fluid. This effect is likely to be more significant in children. Data on 29 children less than 15 kg body weight are presented. Patients were randomised to receive a prime containing one of three crystalloid priming fluids: 100% Hartmann's (H), 50% Hartmann's + 50% 5%-Dextrose (HD), or 100% Plasmalyte 148 (P). The remainder of the prime was CPD stored blood and the prime was buffered with sodium bicarbonate. Severe hyperglycaemia 22.4 +/- 1.3 mmol/l occurred during bypass in the HD group but moderate hyperglycaemia occurred in the other prime groups. Hyperlactataemia occurred in all prime groups during bypass and was highest in the H prime group at 3.9 +/- 0.4 mmol/l. These changes in intermediary metabolites were only partly explained by the crystalloid components of the priming fluid. A subsiduary study revealed the important contribution of CPD stored blood to those intermediary metabolite concentrations. Therefore, the well recognised changes in intermediary metabolites as components of the metabolic response to surgery, namely hyperglycaemia and hyperlactataemia were augmented by the composition of the priming fluids. In addition, CPD stored blood and the sodium bicarbonate buffer increased the sodium concentration of the prime to hypernatraemic levels in both the H and P groups which caused an increase in sodium concentration during bypass. Therefore important changes during bypass occur as a direct result of the individual components of the priming fluid. These changes may result in osmolal flux, hyperglycaemia and hyperlactataemia, all of which have been reported to be potentially harmful.

Doppler mapping of postoperative left atrioventricular valve regurgitation

Left atrioventricular valve regurgitation often occurs as a postoperative hemodynamic complication from repair of an atrioventricular septal defect. In this study, cross-sectional two-dimensional Doppler flow mapping of the left atrium was used to quantify postoperative regurgitant flow in 29 patients. Its severity and location was related to the shape of the three leaflets of the left component of the atrioventricular valve, especially to the size of the mural leaflet. To identify which leaflet configuration was likely to cause regurgitation, the position of the leaflets was obtained from the parasternal short-axis view and the angular size of the mural leaflet expressed in degrees of an arc. Doppler mapping was performed in the apical four-chamber and the parasternal long-axis views, dividing the left atrium in nine squares in each. Regurgitation was defined as a jetlike systolic downstroke of the Doppler frequency shift in early systole. The angular size of the mural leaflet varied from 38 to 144 degrees (mean 86 +/- 36 SD). Massive regurgitation (six to nine sites) was encountered in seven patients, five with a mural leaflet size of over 110 degrees, one with mural leaflet size between 70 and 110 degrees, and one with a mural leaflet size of under 70 degrees. No or minimal regurgitation was encountered in 10 patients, three having a mural leaflet size of 70 to 110 degrees and seven with a mural leaflet size of less than 70 degrees. These data suggest that massive regurgitation is encountered in patients with large mural leaflets, whereas patients with smaller mural leaflets tend to have no or mild regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Surgery for congenital abnormalities of the mitral valve at the Hospital for Sick Children, London from 1969-1983

The surgical management of congenital mitral valve (MV) anomalies remains controversial and complex. Valve repair has been said to be preferable to valve replacement. To assess the validity of this suggestion we have reviewed our experience of these procedures at The Hospital for Sick Children, Great Ormond Street, London from 1969-1983. In that time 48 patients have undergone surgery; in 23 repair was practicable (Group A) and in 25 replacement of the MV was required (Group B). Group A patients were slightly older than group B patients (5.9 +/- 1.0 years (SEM) vs 3.6 +/- 0.5 years). Björk Shiley valves were the predominant prosthesis used. Overall mortality was 33%, with 17% in Group A and 48% in Group B. Hospital mortality was 4.5% in Group A and 28% in Group B. Actuarial survival for Group A was 90% at 1 year, and 75% at 2 and 5 years; for Group B it was 52% at 1 and 2 years and 42% at 5 years. Mortality was significantly higher in those aged less than 5 years. Four patients in Group A have required re-operation, in 3 valve replacement was required; 2 of these died in hospital. One patient in Group B has required reoperation for valve-related thromboembolism. Three patients are awaiting replacement of calcified bioprostheses. These data support the concept that repair of MV should be performed where possible. The severity of the anomalies was greater in Group B and a rethink as to whether valve replacement is the best option for severe mitral stenosis in those aged less than 5 years seems indicated, in view of the very high mortality.

Left-ventricular cavity dimensions in children with normal and dilated hearts

Studies were carried out to find how left-ventricular length and length/diameter ratio relate to body size and degree of dilation. By use of M-mode and two-dimensional echocardiography, diastolic cavity long axis (Led), diastolic cavity diameter (Ded), systolic cavity long axis (Les), systolic cavity diameter (Des), fractional L shortening (SFL), and fractional D shortening (SFD) were measured in children, adolescents, and young adults between two and 23 years of age, with body-surface area (BSA) between 0.5 and 2.1 m2 and with a variety of volume loads and SFD values. In normal subjects, Led/Ded was about 1.9. Regardless of age and pathology (in this age range), Led correlated consistently with BSA (Led = 3.9 + 3.2 BSA), indicating that the long axis changes rather little with pathological dilation. A plot of Led/Ded vs BSA/D2ed (in m2/cm2) formed a straight-line relation: Led/Ded = 0.77 + 16.4 BSA/D2ed. Similar relations were found for end-systolic dimensions. End-systolic L/D ratio exceeded end-diastolic L/D ratio to a degree that depended on both end-diastolic L/D ratio and SFD:Les/Des = Led/Ded + (0.22 + 2.67 Led/Ded)(SFD)2. Relations like these may be useful in the interpretation of echocardiographic images. The results suggest that left-ventricular L/D ratio may be influenced by myocardial anisotropy (dominance of hoop over meridional fiber orientation tending to promote prolate shape especially during systole) and external factors that antagonize extension of the long axis.