Cardiac MRI in diagnosis, prognosis, and follow-up of hypertrophic cardiomyopathy in children: current perspectives

Hypertrophic Cardiomyopathy (HCM) is an inherited myocardial disease characterised by left ventricular hypertrophy, which carries an increased risk of life-threatening arrhythmias and sudden cardiac death. The age of presentation and the underlying aetiology have a significant impact on the prognosis and quality of life of children with HCM, as childhood-onset HCM is associated with high mortality risk and poor long-term outcomes. Accurate cardiac assessment and identification of the HCM phenotype are therefore crucial to determine the diagnosis, prognostic stratification, and follow-up. Cardiac magnetic resonance (CMR) is a comprehensive evaluation tool capable of providing information on cardiac morphology and function, flow, perfusion, and tissue characterisation. CMR allows to detect subtle abnormalities in the myocardial composition and characterise the heterogeneous phenotypic expression of HCM. In particular, the detection of the degree and extent of myocardial fibrosis, using late-gadolinium enhanced sequences or parametric mapping, is unique for CMR and is of additional value in the clinical assessment and prognostic stratification of paediatric HCM patients. Additionally, childhood HCM can be progressive over time. The rate, timing, and degree of disease progression vary from one patient to the other, so close cardiac monitoring and serial follow-up throughout the life of the diagnosed patients is of paramount importance. In this review, an update of the use of CMR in childhood HCM is provided, focussing on its clinical role in diagnosis, prognosis, and serial follow-up.

The effects of percutaneous branch pulmonary artery interventions on exercise capacity, lung perfusion, and right ventricular function in biventricular CHD: a systematic review

BACKGROUND

Branch pulmonary artery stenosis is common after surgical repair in patients with biventricular CHD and often requires reinterventions. However, (long-term) effects of percutaneous branch pulmonary artery interventions on exercise capacity, right ventricular function, and lung perfusion remain unclear. This review describes the (long-term) effects of percutaneous branch pulmonary artery interventions on exercise capacity, right ventricular function, and lung perfusion following PRISMA guidelines.

METHODS

We performed a systematic search in PubMed, Embase, and Cochrane including studies about right ventricular function, exercise capacity, and lung perfusion after percutaneous branch pulmonary artery interventions. Study selection, data extraction, and quality assessment were performed by two researchers independently.

RESULTS

In total, 7 eligible studies with low (n = 2) and moderate (n = 5) risk of bias with in total 330 patients reported on right ventricular function (n = 1), exercise capacity (n = 2), and lung perfusion (n = 7). Exercise capacity and lung perfusion seem to improve after a percutaneous intervention for branch pulmonary artery stenosis. No conclusions about right ventricular function or remodelling, differences between balloon and stent angioplasty or specific CHD populations could be made.

CONCLUSION

Although pulmonary artery interventions are frequently performed in biventricular CHD, data on relevant outcome parameters such as exercise capacity, lung perfusion, and right ventricular function are largely lacking. An increase in exercise capacity and improvement of lung perfusion to the affected lung has been described in case of mild to more severe pulmonary artery stenosis during relatively short follow-up. However, there is need for future studies to evaluate the effect of pulmonary artery interventions in various CHD populations.

Penetrance and Prognosis of MYH7 Variant-Associated Cardiomyopathies: Results From a Dutch Multicenter Cohort Study

BACKGROUND

MYH7 variants cause hypertrophic cardiomyopathy (HCM), noncompaction cardiomyopathy (NCCM), and dilated cardiomyopathy (DCM). Screening of relatives of patients with genetic cardiomyopathy is recommended from 10 to 12 years of age onward, irrespective of the affected gene.

OBJECTIVES

This study sought to study the penetrance and prognosis of MYH7 variant-associated cardiomyopathies.

METHODS

In this multicenter cohort study, penetrance and major cardiomyopathy-related events (MCEs) were assessed in carriers of (likely) pathogenic MYH7 variants by using Kaplan-Meier curves and log-rank tests. Prognostic factors were evaluated using Cox regression with time-dependent coefficients.

RESULTS

In total, 581 subjects (30.1% index patients, 48.4% male, median age 37.0 years [IQR: 19.5-50.2 years]) were included. HCM was diagnosed in 226 subjects, NCCM in 70, and DCM in 55. Early penetrance and MCEs (age <12 years) were common among NCCM-associated variant carriers (21.2% and 12.0%, respectively) and DCM-associated variant carriers (15.3% and 10.0%, respectively), compared with HCM-associated variant carriers (2.9% and 2.1%, respectively). Penetrance was significantly increased in carriers of converter region variants (adjusted HR: 1.87; 95% CI: 1.15-3.04; P = 0.012) and at age ≤1 year in NCCM-associated or DCM-associated variant carriers (adjusted HR: 21.17; 95% CI: 4.81-93.20; P < 0.001) and subjects with a family history of early MCEs (adjusted HR: 2.45; 95% CI: 1.09-5.50; P = 0.030). The risk of MCE was increased in subjects with a family history of early MCEs (adjusted HR: 1.82; 95% CI: 1.15-2.87; P = 0.010) and at age ≤5 years in NCCM-associated or DCM-associated variant carriers (adjusted HR: 38.82; 95% CI: 5.16-291.88; P < 0.001).

CONCLUSIONS

MYH7 variants can cause cardiomyopathies and MCEs at a young age. Screening at younger ages may be warranted, particularly in carriers of NCCM- or DCM-associated variants and/or with a family history of MCEs at <12 years.

Diagnostic Accuracy of Physical Examination and Pulse Oximetry for Critical Congenital Cardiac Disease Screening in Newborns

BACKGROUND

Newborns with a critical congenital heart disease left undiagnosed and untreated have a substantial risk for serious complications and subsequent failure to thrive. Prenatal ultrasound screening is not widely available, nor is postnatal echocardiography. Physical examination is the standard for postnatal screening. Pulse oximetry has been proposed in numerous studies as an alternative screening method. This systematic review and meta-analysis aims to determine the diagnostic accuracies of both screening methods separately and combined.

METHODS

A systematic literature search of the Embase, PubMed, and Global Health databases up to 30 November 2023 was conducted with the following keywords: critical congenital heart disease, physical examination, clinical scores, pulse oximetry, and echocardiography. The search included all studies conducted in the newborn period using both physical examination and pulse oximetry as screening methods and excluded newborns admitted to the intensive care unit. All studies were assessed for risk of bias and applicability concerns using the QUADAS-2 score. The review adhered to the PRISMA 2020 statement guideline.

RESULTS

Out of 2711 articles, 20 articles were selected as eligible for meta-analysis. Cumulatively, the sample included 872,549 screened newborns. The pooled sensitivity of the physical examination screening method was found to be 0.69 (0.66-0.73 (95% CI)) and specificity was found to be 0.98 (0.98-0.98). For the pulse oximetry screening method, the pooled sensitivity and specificity yielded 0.78 (0.75-0.82) and 0.99 (0.99-0.99), respectively. The combined method of screening yielded improved diagnostic characteristics at a sensitivity and specificity of 0.93 (0.91-0.95) and 0.98 (0.98-0.98, respectively.

CONCLUSIONS

The evidence indicates that combining both physical examination and pulse oximetry to screen for critical congenital heart disease exceeds the accuracy of either separate method. The main limitation is that solely newborns with suspected critical congenital heart disease were subjected to the reference standard. We recommend adapting both methods to screen for critical congenital heart diseases, especially in settings lacking standard fetal ultrasound screening. To increase the sensitivity further, we recommend increasing the screening time window and employing the peripheral perfusion index.

Physical activity in relation to motor performance, exercise capacity, sports participation, parental perceptions, and overprotection in school aged children with a critical congenital heart defect

OBJECTIVE

To depict objectively measured moderate-to-vigorous physical activity (MVPA), motor performance (MP), cardiorespiratory fitness (CRF), organized sports participation, parental perceptions of vulnerability and parenting style in children with a Critical Congenital Heart Disease (CCHD), and to explore whether these factors are associated with MVPA.

STUDY DESIGN

A prospective observational cohort study in 62 7-10 years old children with a CCHD.

RESULTS

On average, children with CCHD spent 64 min on MVPA per day (accelerometry), 61 % met the international WHO physical activity guideline. Only 12 % had >60 min of MVPA daily. Eighteen percent had a motor delay (movement-assessment-battery-for children-II) and 38 % showed a below average CRF (cardiopulmonary exercise test using the Godfrey ramp protocol). Seventy-seven percent participated in organized sports activities at least once a week. Twenty-one percent of the parents are classified as overprotective (parent protection scale) and 7.3 % consider their child as being vulnerable (child vulnerability scale). A significant positive association was found between MVPA and MP (rs = 0.359), CRF(V̇O2peak/ml/kg: rs = 0.472 and Wpeak/kg: rs = 0.396) and sports participation (rs = 0.286). Children who were perceived as vulnerable by their parents showed a significantly lower MVPA (rs = -0.302). No significant associations were found between mean MVPA and parental overprotection.

CONCLUSION

Even though the majority of school aged children with a CCHD is sufficiently active, counseling parents regarding the importance of sufficient MVPA and sports participation, especially in parents who consider their child being vulnerable, could be useful. Since motor delays can be detected at an early age, motor development could be an important target to improve exercise capacity and sports participation to prevent inactivity in children with a CCHD.

Acute and early-onset cardiotoxicity in children and adolescents with cancer: a systematic review

BACKGROUND

Cardiotoxicity is among the most important adverse effects of childhood cancer treatment. Anthracyclines, mitoxantrone and radiotherapy involving the heart are its main causes. Subclinical cardiac dysfunction may over time progress to clinical heart failure. The majority of previous studies have focused on late-onset cardiotoxicity. In this systematic review, we discuss the prevalence and risk factors for acute and early-onset cardiotoxicity in children and adolescents with cancer treated with anthracyclines, mitoxantrone or radiotherapy involving the heart.

METHODS

A literature search was performed within PubMed and reference lists of relevant studies. Studies were eligible if they reported on cardiotoxicity measured by clinical, echocardiographic and biochemical parameters routinely used in clinical practice during or within one year after the start of cancer treatment in ≥ 25 children and adolescents with cancer. Information about study population, treatment, outcomes of diagnostic tests used for cardiotoxicity assessment and risk factors was extracted and risk of bias was assessed.

RESULTS

Our PubMed search yielded 3649 unique publications, 44 of which fulfilled the inclusion criteria. One additional study was identified by scanning the reference lists of relevant studies. In these 45 studies, acute and early-onset cardiotoxicity was studied in 7797 children and adolescents. Definitions of acute and early-onset cardiotoxicity prove to be highly heterogeneous. Prevalence rates varied for different cardiotoxicity definitions: systolic dysfunction (0.0-56.4%), diastolic dysfunction (30.0-100%), combinations of echocardiography and/or clinical parameters (0.0-38.1%), clinical symptoms (0.0-25.5%) and biomarker levels (0.0-37.5%). Shortening fraction and ejection fraction significantly decreased during treatment. Cumulative anthracycline dose proves to be an important risk factor.

CONCLUSIONS

Various definitions have been used to describe acute and early-onset cardiotoxicity due to childhood cancer treatment, complicating the establishment of its exact prevalence. Our findings underscore the importance of uniform international guidelines for the monitoring of cardiac function during and shortly after childhood cancer treatment.

Executive functioning in preschoolers with 22q11.2 deletion syndrome and the impact of congenital heart defects

BACKGROUND

Executive functioning (EF) is an umbrella term for various cognitive functions that play a role in monitoring and planning to effectuate goal-directed behavior. The 22q11.2 deletion syndrome (22q11DS), the most common microdeletion syndrome, is associated with a multitude of both somatic and cognitive symptoms, including EF impairments in school-age and adolescence. However, results vary across different EF domains and studies with preschool children are scarce. As EF is critically associated with later psychopathology and adaptive functioning, our first aim was to study EF in preschool children with 22q11DS. Our second aim was to explore the effect of a congenital heart defects (CHD) on EF abilities, as CHD are common in 22q11DS and have been implicated in EF impairment in individuals with CHD without a syndromic origin.

METHODS

All children with 22q11DS (n = 44) and typically developing (TD) children (n = 81) were 3.0 to 6.5 years old and participated in a larger prospective study. We administered tasks measuring visual selective attention, visual working memory, and a task gauging broad EF abilities. The presence of CHD was determined by a pediatric cardiologist based on medical records.

RESULTS

Analyses showed that children with 22q11DS were outperformed by TD peers on the selective attention task and the working memory task. As many children were unable to complete the broad EF task, we did not run statistical analyses, but provide a qualitative description of the results. There were no differences in EF abilities between children with 22q11DS with and without CHDs.

CONCLUSION

To our knowledge, this is the first study measuring EF in a relatively large sample of young children with 22q11DS. Our results show that EF impairments are already present in early childhood in children with 22q11DS. In line with previous studies with older children with 22q11DS, CHDs do not appear to have an effect on EF performance. These findings might have important implications for early intervention and support the improvement of prognostic accuracy.

Exercise capacity in a cohort of children with congenital heart disease

In patients with congenital heart disease (CHD), reduced exercise capacity can be a predictor for late complications and may be used to guide interventions. Yet, the interpretation of exercise capacity is challenged by changes in body composition during growth. Our aim was to create an overview of disease-specific exercise capacity in children with CHD. We performed a multicentre retrospective study of exercise capacity of CHD patients, aged 6-18 years, tested between January 2001 and October 2018. Sex-specific distribution graphs were made using the LMS method and height to relate to body size. We included all CHD with N > 50, including severe defects (e.g., univentricular heart, tetralogy of Fallot) and "simple" lesions as ventricular septum defect and atrial septum defect. We included 1383 tests of 1208 individual patients for analysis. The peak oxygen uptake (VO₂peak, 37.3 ml/min/kg (25th-75th percentile 31.3-43.8)) varied between specific defects; patients with univentricular hearts had lower VO_2peak compared with other CHD. All groups had lower VO_2peak compared to healthy Dutch children. Males had higher VO_2peak, W_peak and O₂pulse_peak than females. Sex- and disease-specific distribution graphs for VO_2peak, W_peak and O2pulse_peak showed increase in variation with increase in height.   Conclusion: Disease-specific distribution graphs for exercise capacity in children with CHD from a large multicentre cohort demonstrated varying degrees of reduced VO_2peak and W_peak. The distribution graphs can be used in the structured follow-up of patients with CHD to predict outcome and identify patients at risk. What is Known: • Children with congenital heart disease (COnHD) are at risk to develop heart failure, arrhytmia's and other complications. Exercise capacity may be an important predictor for outcome in children with ConHD. In children, the interpretation of exercise capacity poses an additional challenge related to physical changes during growth. What is New: • In this report of a multi-center cohort >1300 childrewn with ConHD, we related the changes in exercise capacity to length. We demonstrated that exercise capacity was reduced as compared with healthy children and we observed variation between disease groups. Patients with a univentricular circulation (Fontan) had worse exercise capacity. We constructed disease specific charts of development of exercise capacity throughout childhood, accessible via a web-site. These graphs may help practitioner to guide children with ConHD.

Motor Developmental Delay After Cardiac Surgery in Children With a Critical Congenital Heart Defect: A Systematic Literature Review and Meta-analysis

PURPOSE

To systematically review evidence regarding the severity and prevalence of motor development in children with a critical congenital heart defect (CCHD) without underlying genetic anomalies.

SUMMARY OF KEY POINTS

Twelve percent of all included studies reported abnormal mean motor developmental scores, and 38% reported below average motor scores. Children with single-ventricle physiology, especially those with hypoplastic left heart syndrome, had the highest severity and prevalence of motor delay, particularly at 0 to 12 months. Most included studies did not differentiate between gross and fine motor development, yet gross motor development was more affected.

RECOMMENDATIONS FOR CLINICAL PRACTICE

We recommend clinicians differentiate between the type of heart defect, fine and gross motor development, and the presence of genetic anomalies. Furthermore, increased knowledge about severity and prevalence will enable clinicians to tailor their interventions to prevent motor development delays in CCHD.

Patient information portal for congenital aortic and pulmonary valve disease: a stepped-wedge cluster randomised trial

BACKGROUND

In response to an increased need for patient information in congenital heart disease, we previously developed an online, evidence-based information portal for patients with congenital aortic and pulmonary valve disease. To assess its effectiveness, a stepped-wedge cluster randomised trial was conducted.

METHODS

Adult patients and caregivers of paediatric patients with congenital aortic and/or pulmonary valve disease and/or tetralogy of Fallot who visited the outpatient clinic at any of the four participating centres in the Netherlands between 1 March 2016-1 July 2017 were prospectively included. The intervention (information portal) was introduced in the outpatient clinic according to a stepped-wedge randomised design. One month after outpatient clinic visit, each participant completed a questionnaire on disease-specific knowledge, anxiety, depression, mental quality of life, involvement and opinion/attitude concerning patient information and involvement.

RESULTS

343 participants were included (221 control, 122 intervention). Cardiac diagnosis (p=0.873), educational level (p=0.153) and sex (p=0.603) were comparable between the two groups. All outcomes were comparable between groups in the intention-to-treat analyses. However, only 51.6% of subjects in the intervention group (n=63) reported actually visiting the portal. Among these subjects (as-treated), disease-specific knowledge (p=0.041) and mental health (p=0.039) were significantly better than in control subjects, while other baseline and outcome variables were comparable.

CONCLUSION

Even after being invited by their cardiologists, only half of the participants actually visited the information portal. Only in those participants that actually visited the portal, knowledge of disease and mental health were significantly better. This underlines the importance of effective implementation of online evidence-based patient information portals in clinical practice.

Two decades of aortic coarctation treatment in children; evaluating techniques

Objective

This study focuses on the evolution of treatment techniques for aortic coarctation in children and assesses long-term morbidity.

Methods

This retrospective cohort study evaluates patients treated for native aortic coarctation, with at least 7 years of follow-up. To assess time-related changes, three time periods were distinguished according to year of primary intervention (era 1, 2 and 3). Operative and long-term follow-up data were collected by patient record reviews.

Results

The study population consisted of 206 patients (177 surgical and 29 catheter-based interventions), with a median follow-up of 151 months. Anterior approach with simultaneous repair of aortic arch and associated cardiac lesions was more common in the most recent era. Median age at intervention did not change over time. Reintervention was necessary in one third of the cohort with an event-free survival of 74% at 5‑year and 68% at 10-year follow-up. Reintervention rates were significantly higher after catheter-based interventions compared with surgical interventions (hazard ratio [HR] 1.8, 95% confidence interval [CI] 1.04–3.00, p = 0.04) and in patients treated before 3 months of age (HR 2.1, 95% CI 1.27–3.55, p = 0.003). Hypertension was present in one out of five patients.

Conclusion

Nowadays, complex patients with associated cardiac defects and arch hypoplasia are being treated surgically on bypass, whereas catheter-based intervention is introduced for non-complex patients. Reintervention is common and more frequent after catheter-based intervention and in surgery under 3 months of age. One fifth of the 206 patients remained hypertensive.

Long-Term Follow-Up of Pericardium for the Ventricular Component in Atrioventricular Septal Defect Repair

BACKGROUND

Despite the improved outcome in complete atrioventricular septal defect (AVSD) repair, reoperations for left atrioventricular valve (LAVV) dysfunction are common. The aim of this study was to evaluate the effect of fresh untreated autologous pericardium for ventricular septal defect (VSD) closure on atrioventricular valve function and compare the results with the use of treated bovine pericardial patch material.

METHODS

Clinical and echocardiographic data were collected of patients with complete AVSD with their VSD closed with either untreated autologous pericardial or treated bovine pericardial patch material between January 1, 1996, and December 31, 2003. Evaluation closed in September 2019.

RESULTS

A total of 77 patients were analyzed (untreated autologous pericardial VSD patch: 59 [77%], treated bovine pericardial VSD patch: 18 [23%]). Median age at surgery was 3.6 (interquartile range [IQR]: 2.7-4.5) months, and median weight was 4.5 (IQR: 3.9-5.1) kg. Trisomy 21 was present in 70 (91%) patients. Median follow-up time was 17.5 (IQR: 12.6-19.8) years. Death <30 days occurred in two (3%) patients. Reinterventions occurred in eight patients (early [within 30 days] in two, early and late in one, and late in five), all in the autologous pericardium group. Log-rank tests showed no significant difference in mortality (P = .892), LAVV reinterventions (P = .228), or LAVV regurgitation (P = .770).

CONCLUSIONS

In AVSD, the VSD can safely be closed with either untreated autologous pericardium or xeno-pericardium. We found no difference in LAVV regurgitation or the need for reoperation between the two patches.

Mechanical Mitral Valve Replacement: A Multicenter Study of Outcomes With Use of 15- to 17-mm Prostheses

BACKGROUND

The aim of this study was to evaluate early and mid-term outcomes (mortality and prosthetic valve reintervention) after mitral valve replacement with 15- to 17-mm mechanical prostheses.

METHODS

A multicenter, retrospective cohort study was performed among patients who underwent mitral valve replacement with a 15- to 17-mm mechanical prosthesis at 6 congenital cardiac centers: 5 in The Netherlands and 1 in the United States. Baseline, operative, and follow-up data were evaluated.

RESULTS

Mitral valve replacement was performed in 61 infants (15 mm, n = 17 [28%]; 16 mm, n = 18 [29%]; 17 mm, n = 26 [43%]), of whom 27 (47%) were admitted to the intensive care unit before surgery and 22 (39%) required ventilator support. Median age at surgery was 5.9 months (interquartile range [IQR] 3.2-17.4), and median weight was 5.7 kg (IQR, 4.5-8.8). There were 13 in-hospital deaths (21%) and 8 late deaths (17%, among 48 hospital survivors). Major adverse events occurred in 34 (56%). Median follow-up was 4.0 years (IQR, 0.4-12.5) First prosthetic valve replacement (n = 27 [44%]) occurred at a median of 3.7 years (IQR, 1.9-6.8). Prosthetic valve endocarditis was not reported, and there was no mortality related to prosthesis replacement. Other reinterventions included permanent pacemaker implantation (n = 9 [15%]), subaortic stenosis resection (n = 4 [7%]), aortic valve repair (n = 3 [5%], and aortic valve replacement (n = 6 [10%]).

CONCLUSIONS

Mitral valve replacement with 15- to 17-mm mechanical prostheses is an important alternative to save critically ill neonates and infants in whom the mitral valve cannot be repaired. Prosthesis replacement for outgrowth can be carried out with low risk.

Follow-up after biventricular repair of the hypoplastic left heart complex

OBJECTIVES

In hypoplastic left heart complex patients, biventricular repair is preferred over staged-single ventricle palliation; however, there are too few studies to support either strategy. Therefore, we retrospectively characterized our patient cohort with hypoplastic left heart complex after biventricular repair to measure left-sided heart structures and assess our treatment strategy.

METHODS

Patients with hypoplastic left heart complex who had biventricular repair between 2004 and 2018 were retrospectively reviewed. Operative results were evaluated and echocardiographic mitral valve (MV) and aortic valve (AoV) dimensions, left ventricular length and left ventricular internal diastolic diameter (LVIDd) were measured preoperatively and during follow-up after 0.5, 1, 3, 5 and 10 years.

RESULTS

In 32 patients, the median age at surgery was 10 (interquartile range 5.0) days. The median follow-up was 6.19 (interquartile range 6.04) years. During the 10-year follow-up, the mean Z-scores increased from -2.82 to -1.49 and from -2.29 to 0.62 for MV and AoV, respectively. Analysis of variance results with post hoc paired t-tests showed that growth of left-sided heart structures was accelerated in the first year after repair, but was not equal, with the MV lagging behind the AoV (P = 0.033), resulting in significantly smaller MV Z-scores compared with AoV Z-scores at 10-year follow-up (P < 0.001). There were 2 (6%) early deaths. The major adverse events occurred in 4 (13%) patients. The surgical or catheter-based reintervention was required in 14 (44%) patients.

CONCLUSIONS

The growth rate of heart structures was most prominent during the first year after biventricular repair with lower growth rate of the MV compared with the AoV.

Echocardiographic Assessment of Cardiac Function in Pediatric Survivors of Anthracycline-Treated Childhood Cancer

BACKGROUND

Anthracycline-induced cardiotoxicity is a major cause of morbidity and mortality in childhood cancer survivors (CCSs). Echocardiographic myocardial strain imaging is recommended in adult patients with cancer, but its role in pediatric CCSs has not been well established. Aims of this study were to determine the prevalence of abnormalities in left ventricular strain in pediatric CCSs, to compare strain with other echocardiographic measurements and blood biomarkers, and to explore risk factors for reduced strain.

METHODS

CCSs ≥3 years from their last anthracycline treatment were enrolled in this multicenter study and underwent a standardized functional echocardiogram and biomarker collection. Regression analysis was used to identify factors associated with longitudinal strain (LS).

RESULTS

Five hundred forty-six pediatric CCSs were compared with 134 healthy controls. Abnormal left ventricular ejection fraction (<50%) and mean LS (Z score, <-2) was found in 0.8% and 7.7% of the CCSs, respectively. LS was significantly lower in CCSs than in controls, but the absolute difference was small (0.7%). Lower LS in CCSs was associated with older current age and higher body surface area. Sex, cumulative anthracycline dose, radiotherapy, and biomarkers were not independently associated with LS. Circumferential strain, diastolic parameters, and biomarkers were not significantly different in pediatric CCSs.

CONCLUSIONS

Global systolic function and LS are only mildly reduced in pediatric CCSs, and most LS values are within normal range. This makes single LS measurements of limited added value in identifying CCSs at risk for cardiac dysfunction. The utility of strain imaging in the long-term follow-up of CCS remains to be demonstrated.

Medium-term systemic blood pressure after stenting of aortic coarctation: a systematic review and meta-analysis

OBJECTIVE

Long-term prognosis of patients with coarctation of the aorta (CoA) is impaired due to the high prevalence of hypertension and consequent cardiovascular complications. Although stent implantation results in acute anatomical and haemodynamic benefit, limited evidence exists regarding the late clinical outcome. In this meta-analysis, we aimed to evaluate the medium-term effect of stent placement for CoA on systemic blood pressure (BP).

METHODS

PubMed, EMBASE and Cochrane databases were searched for non-randomised cohort studies addressing systemic BP ≥12 months following CoA stenting. Meta-analysis was performed on the change in BP from baseline to last follow-up using a random-effects model. Subgroup analyses and meta-regression were conducted to identify sources of heterogeneity between studies.

RESULTS

Twenty-six studies with a total of 1157 patients and a median follow-up of 26 months were included for final analysis. Meta-analysis showed a 20.3 mm Hg (95% CI 16.4 to 24.1 mm Hg; p<0.00001) reduction in systolic BP and an 8.2 mm Hg (12 studies; 95% CI 5.2 to 11.3 mm Hg; p<0.00001) reduction in diastolic BP. A concomitant decrease in the use of antihypertensive medication was observed. High systolic BP and peak systolic gradient at baseline and stenting of native CoA were associated with a greater reduction in systolic BP at follow-up.

CONCLUSIONS

Stent implantation for CoA is associated with a significant decline in systolic and diastolic BP during medium-term follow-up. The degree of BP reduction appears to be dependent on baseline systolic BP, baseline peak systolic gradient, and whether stenting is performed for native or recurrent CoA.

Pre-intervention morphologic and functional echocardiographic characteristics of neonates with critical left heart obstruction: a Congenital Heart Surgeons Society (CHSS) inception cohort study

AIMS

The aims of this study were to provide a detailed descriptive analysis of pre-intervention morphologic and functional echocardiographic parameters in a large, unselected, multicentre cohort of neonates diagnosed with critical left heart obstruction and to compare echocardiographic features between the different subtypes of left-sided lesions.

METHODS AND RESULTS

Pre-intervention echocardiograms for 651 patients from 19 Congenital Heart Surgeons' Society (CHSS) institutions were reviewed in a core lab according to a standardized protocol including >150 morphologic and functional variables. The four most common subtypes of lesions were: aortic atresia (AA)/mitral atresia (MA) (29% of patients), AA/mitral stenosis (MS) (20%), aortic stenosis (AS)/MS (26%), and isolated AS (iAS) (18%). Only 17% of patients with AS/MS had an apex-forming left ventricle, compared with 0% of those with AA/MA and AA/MS (P < 0.0001). Aortic arch hypoplasia and coarctation were common across all four groups, while those with AA/MA and AA/MS had the smallest ascending aorta diameters. Flow in the ascending aorta was retrograde in 43% and 10% of the patients with AS/MS and iAS, respectively. The right ventricle was apex forming in 100% of patients with AA/MA and AA/MS, 96% with AS/MS and 70% with iAS (P < 0.0001). Moderate to severe tricuspid regurgitation was present in 13% of all patients.

CONCLUSION

This large multi-institutional study generates insight into the distribution of the functional and morphologic spectrum in patients with critical left-sided heart disease and identifies differences in these functional and morphologic characteristics between the main anatomic subtypes of critical left heart obstruction.

Exercise Capacity in Asymptomatic Adult Patients Treated for Coarctation of the Aorta

A reduced exercise capacity is a common finding in adult congenital heart disease and is associated with cardiovascular morbidity and mortality. However, data on exercise capacity in patients after repair of coarctation of the aorta (CoA) are scarce. Furthermore, a high rate of exercise-induced hypertension has been described in CoA patients. This study sought to assess exercise capacity and blood pressure response in asymptomatic patients long-term after CoA repair in relation to left ventricular and vascular function. Twenty-two CoA patients (age 30 ± 10.6 years) with successful surgical repair (n = 12) or balloon angioplasty (n = 10) between 3 months and 16 years of age with a follow-up of > 10 years underwent cardiopulmonary exercise testing at a mean follow-up of 23.9 years. Exercise capacity (peak oxygen uptake; VO_2peak) and blood pressure response were compared to age- and gender-matched reference values. Left ventricular function and volumetric analysis was performed using cardiovascular magnetic resonance imaging. CoA patients showed preserved exercise capacity compared to the healthy reference group, with a VO_2peak of 41.7 ± 12.0 ml/kg/min versus 44.9 ± 6.7 ml/kg/min. VO_2peak/kg showed a significant association with age (p < 0.001) and male gender (p ≤ 0.001). Exercise-induced hypertension occurred in 82% of CoA patients, and was strongly related to left ventricular mass (p = 0.04). Of the 41% of patients who were normotensive at rest, 78% showed exercise-induced hypertension. No significant correlation was found between peak exercise blood pressure and age, BMI, age at time of repair, LVEF, or LV dimensions. Exercise capacity is well preserved in patients long-term after successful repair of coarctation of the aorta. Nevertheless, a high number of patients develop exercise hypertension, which is strongly related to systemic hypertension. Regular follow-up, including cardiopulmonary exercise testing, and aggressive treatment of hypertension after CoA repair is strongly advised.

Arterioventricular interaction after coarctation repair

BACKGROUND

Hypertension is common in patients with coarctation of the aorta (CoA), even after successful repair. Increased aortic stiffness has been implicated in the pathology of CoA-associated hypertension. This study aimed to investigate aortic vascular function and its relationship with hypertension in well-repaired CoA-patients at long-term follow-up. Furthermore, we assessed the additive effect of hypertension to adverse arterioventricular coupling associated with increased aortic stiffness.

METHODS

Twenty-two CoA-patients (age 30 ± 10.6 years) with successful surgical repair (n = 12) or balloon angioplasty (BA) (n = 10) between 3 months and 16 years of age with a follow-up of >10 years and 22 healthy controls underwent cardiac magnetic resonance imaging (CMR), at mean follow-up of 29.3 years, to study aortic pulse wave velocity (PWV), aortic distensibility, global left ventricular (LV) function, LV dimensions, and LV myocardial deformation.

RESULTS

CoA-patients had significantly increased aortic arch PWV (5.6 ± 1.9 m/s vs. 4.5 ± 1.0 m/s, P = .02) and decreased distensibility (4.5 ± 1.8 × 10-3 mmHg^-1 vs. 5.8 ± 1.8 × 10-3 mmHg^-1, P = .04) compared to controls. Significant differences in aortic arch PWV were found between hypertensive patients, normotensive patients and controls (6.1 ± 1.8 m/s vs. 4.9 ± 1.9 m/s and 4.5 ± 1.0 m/s, respectively, P = .03). Aortic arch PWV and distensibility were correlated with systolic blood pressure (R = 0.37 and R = -0.37, respectively, P = .03 for both). Global LV function, LV mass, LV dimensions and myocardial deformation were similar in CoA-patients when compared to controls.

CONCLUSIONS

Central aortic stiffness is significantly increased in well-repaired CoA-patients long-term after repair, and is associated with hypertension. Global LV function, myocardial deformation indices and LV dimensions are however preserved.

Normative Values of Aortic Arch Structures in Premature Infants

BACKGROUND

Aortic arch abnormalities represent 5% to 8% of all congenital heart disease. Measurements of the aortic arch dimensions on two-dimensional echocardiographic images remain of critical importance in the diagnosis of aortic arch pathology. To define aortic hypoplasia or coarctation, measured dimensions must be compared with normal values. Normal values have been described for children of all ages in earlier studies. However, normative data for premature infants are not yet available. Therefore, the aim of this study was to develop normative data in a cohort of premature infants, which could be used in the diagnosis of aortic arch abnormalities.

METHODS

A single-center study was conducted in a large population of premature infants with gestational ages of ≤32 weeks without hemodynamically important congenital heart disease, chromosomal abnormalities, and/or major cerebral congenital malformations. Two-dimensional echocardiographic measurements of four aortic arch structures were made on the second, fourth, and sixth days after birth.

RESULTS

Three hundred eighty-five preterm patients were included. No differences in dimensions were found among days 2, 4, and 6. The dimension of the isthmus showed no significant relation to the existence of a patent ductus arteriosus. Reference intervals with mean and SD were calculated across the range of birth weight. Regression analysis was performed with multiple determinants in different models. The best predictive value was found for birth weight in a cubic model.

CONCLUSIONS

This work provides regression equations for the calculation of Z scores and reference intervals for aortic arch dimensions in a cohort of preterm infants born at gestational ages of ≤32 weeks. The normative data can be used in diagnosis and decision making involving aortic arch pathology in premature infants.

Surgical Repair of Ventricular Septal Defect; Contemporary Results and Risk Factors for a Complicated Course

Surgical closure of the ventricular septal defect is the most commonly performed procedure in pediatric cardiac surgery. There are conflicting data on weight at operation as risk factor for a complicated course. We performed a retrospective evaluation of mortality and morbidity in all patients undergoing surgical ventricular septal defect closure at our institution between 2004 and 2012 to identify risk factor for a complicated course. Multivariate logistic regression modeling was performed to identify risk factors for a complicated course. 243 patients who underwent surgical ventricular septal defect closure were included. Median age at operation was 168.0 days (range 17-6898), the median weight 6.0 kg (range 2.1-102.0). No deaths occurred. Two patients (0.8%) required a pacemaker for permanent heart block. Five patients (2.1%) underwent reoperation for a hemodynamically important residual ventricular septal defect. No other major adverse events occurred. No risk factors for major adverse events could be established. Multivariate analysis identified a genetic syndrome, long bypass time and low weight at operation as independent risk factors for a prolonged intensive care stay (>1 day) and prolonged ventilation time (>6 h). Contemporary results of surgical VSD closure are excellent with no mortality and low morbidity in this series. Although it is associated with increased ventilation time and a longer hospital stay, low bodyweight at operation is not associated with an increased risk of complications or major adverse events in our series.

Is cardiovascular evaluation necessary prior to and during beta-blocker therapy for infantile hemangiomas?: A cohort study

BACKGROUND

Although consensus guidelines for pretreatment evaluation and monitoring of propranolol therapy in patients with infantile hemangiomas (IH) have been formulated, little is known about the cardiovascular side effects.

OBJECTIVES

We sought to analyze cardiovascular evaluations in patients with IH at baseline and during treatment with an oral beta-blocker.

METHODS

Data from 109 patients with IH were retrospectively analyzed. Patient and family history, pretreatment electrocardiogram (ECG), heart rate, and blood pressure were evaluated before initiation of beta-blocker therapy. Blood pressure and standardized questionnaires addressing side effects were evaluated during treatment.

RESULTS

Questionnaire analyses (n = 83) identified 3 cases with a family history of cardiovascular disease in first-degree relatives. ECG findings were normal in each case and no serious complication of therapy occurred. ECG abnormalities were found in 6.5% of patients but there were no contraindications to beta-blocker therapy and no major complications. Hypotension in 9 patients did not require therapy adjustment. In all, 88 parents (81%) reported side effects during beta-blocker treatment.

LIMITATIONS

The relatively small patient cohort is a limitation.

CONCLUSION

Pretreatment ECG is of limited value for patients with an unremarkable cardiovascular history and a normal heart rate and blood pressure. Hypotension may occur during treatment.

Comparability of Z-score equations of cardiac structures in hypoplastic left heart complex

BACKGROUND

Hypoplastic left heart complex (HLHC) is characterized by a mitral valve or an aortic valve annular Z score < -2, antegrade flow in the ascending aorta, ductal dependency, coarctation or aortic arch hypoplasia, and absence of significant (sub)valvar stenosis. The Z scores of the mitral and aortic valve annuli are major determinants of HLHC. Therefore, the algorithm for Z-score calculation is essential for diagnosis. However, no single universal method of calculation is in use. In the scientific literature addressing HLHC, various Z-score calculation methods have been applied. The aim of this study was to evaluate Z scores derived from two-dimensional echocardiographic dimensions in patients with HLHC.

METHODS

To compare the different published methods using two-dimensional echocardiographic measures for Z-score calculation, a cohort of 18 newborns diagnosed with HLHC was retrospectively evaluated. In addition, the methods to determine body surface area in newborns were evaluated.

RESULTS

Three Z-score calculation methods were included and compared. Using the method of Daubeney et al. to calculate Z scores in our cohort illustrated a lack of correlation beyond a Z score < 0, compared with the methods of Zilberman et al. and Pettersen et al. Z scores calculated using Zilberman et al.'s and Pettersen et al.'s methods were fairly consistent. The equations used by Pettersen et al. are based on the largest population of neonates.

CONCLUSION

Although the different methods for calculating Z scores for mitral and aortic valve dimensions correspond fairly well in the normal range, Z scores < -2 diverge substantially. A useful scientific comparison of published data and outcomes of patients with HLHC remains elusive. The Z-score calculation algorithms used by Pettersen et al. appear to be the most appropriate for use in an evaluation of HLHC. Because these different methods can yield different values, reporting the method as well as the Z score is essential for an accurate diagnosis. Similarly, the method used to determine body surface area should be reported.

A prediction rule for food challenge outcome in children

BACKGROUND

In children with food-related symptoms, a food challenge is considered as the gold standard to diagnose allergy. If food allergy could be predicted by patient history and/or diagnostic tests, the number of time-consuming and sometimes risky food challenges could be decreased. We aimed to determine questionnaire and test-based characteristics, to predict the food challenge outcome (FCO) in children referred to a tertiary centre for the evaluation of food-related symptoms.

METHODS

Pre-challenge standardized questionnaires, skin prick tests (SPT), and specific IgE levels (sIgE) were obtained in patients that underwent a food challenge in our hospital in 2009. Characteristics of patients with positive and negative FCO were compared, and uni- and multivariate associations between predictors and FCO were calculated. Based on the multivariate model, a risk score was developed to predict the FCO.

RESULTS

One hundred and twenty-nine challenges were analyzed, 41.9% had a positive outcome. Median age of both groups was 4.9 yrs (range 2.8-8.3). Patients with a positive FCO reacted faster with symptoms after allergen ingestion and had higher sIgE levels compared to children with negative FCO. A clinical risk score was developed based on the index food, 'time between allergen ingestion and complaints' and sIgE levels (range 0-10). The prognostic capacity of this model (AUC) was excellent (0.90). The very high- and low-risk groups (24% of patients) are both predicted excellent without misclassification.

CONCLUSION

Positive FCO can be predicted by the index food, time between allergen ingestion and development of symptoms, and the sIgE level.

No positive effect of rhdnase on the pulmonary colonization in children with cystic fibrosis

BACKGROUND

Long-term clinical trials have shown that daily treatment with recombinant human deoxyribonuclease (rhDNAse) in patients with mild to moderate cystic fibrosis (CF) improves lung function and decreases the number of respiratory exacerbations. The aim of this study was to analyze the effect of rhDNAse on the bacterial colonization of the airways in children with CF.

METHODS

This was a retrospective cohort study. From the database of the CF Center Utrecht, we selected two groups, an rhDNAse group (daily 2.5 mg rhDNAse) and a control group (no rhDNAse). Primary outcome parameter was the difference in change in bacterial colonization between the treatment and control group during 1.5-year. Secondary outcome parameters were changes in lung function (FEV1) and pulmonary exacerbations.

RESULTS

Children treated with rhDNAse showed no significant changes in bacterial colonization during the treatment period, apart from an increase of P. aeruginosa positive cultures, both compared to baseline (53.1% versus 25%, p < 0.05) and control group (no change during study period, 37% versus 37%). The change in FEV1 after one year of treatment was +4.0% in the treatment group versus -0.3% in the control group (p = 0.22). There were no significant changes in number of pulmonary exacerbations.

CONCLUSIONS

This study showed no significant beneficial decrease in bacterial airway colonization during 1.5-year of treatment with rhDNAse. The positive effects of rhDNAse on the lung function can therefore not be explained by a change in airway colonization.

Long-term effects of birth order and age at diagnosis in cystic fibrosis: a sibling cohort study

BACKGROUND

Siblings with cystic fibrosis (CF) share many genetic and environmental factors but may present different phenotypes. Younger sibs are mostly earlier diagnosed with CF than their older sibs, but might be at risk for an earlier colonization with Pseudomonas aeruginosa (PA) than their older counterparts due to cross-infection within families.

AIMS

To analyze the effects of birth order and age at diagnosis on lung function, PA colonization, nutritional status, and survival during the first two decades of life in siblings with CF.

METHODS

A retrospective cohort study of 52 sibling pairs was performed in two Dutch CF centers. Data were analyzed both cross-sectionally and longitudinally using Kaplan-Meier curves and modified log-rank tests.

RESULTS

Median age at diagnosis was significantly higher in the older sib compared with the younger sib (3.0 and 0.2 years, respectively, P < 0.0001). At the age of 5, 10, and 15 years no difference in lung function was found. However, at the age of 20 years, forced expiratory volume in 1 sec (FEV(1)) in older sibs was 19.4% (95% CI: 5.9-32.9%, P = 0.007) lower than in younger sibs. In the younger sibs group, FEV(1) at age 20 years was significantly better in those who had a diagnosis before the age of 6 months (difference 22.9%, 95% CI: 0.1-45.8%, P < 0.05). In the first 10 years of life the younger sibs tended to be earlier colonized with PA than their older counterparts. No differences in nutritional status and survival were observed.

CONCLUSION

In this sibling cohort study, an early diagnosis of CF was associated with better lung function after two decades of life. Although younger siblings tended to be colonized with PA at an earlier age, they showed better lung function outcomes. This underscores the importance of early diagnosis with newborn screening and early referral to a specialized center in the prevention of long-term deleterious effects on lung function.

Bilateral traumatic carotid artery dissection in a child

Traumatic dissection of the carotid artery is an infrequent but serious complication of blunt craniocervical injury. There is controversy regarding the need for diagnostic screening and management. This report presents a child with delayed neurologic symptoms and multiple cerebral infarcts secondary to bilateral extracranial traumatic carotid artery dissection. The pathophysiology, clinical presentation, and treatment options of blunt carotid artery trauma are discussed.

Diagnostic value of serological tests against Pseudomonas aeruginosa in a large cystic fibrosis population

BACKGROUND

Serological methods to monitor Pseudomonas aeruginosa colonisation in patients with cystic fibrosis (CF) are advocated but the diagnostic value of a commercially available P aeruginosa antibody test to detect early and chronic P aeruginosa colonisation in a non-research setting has not been assessed.

METHODS

Colonisation with P aeruginosa was estimated by regular culture of sputum or oropharyngeal swabs during three consecutive years in 220 patients with CF aged 0-65 years. Commercially available ELISA tests with three P aeruginosa antigens (elastase, exotoxin A, alkaline protease) were performed at the end of the study period. In a subgroup of 57 patients (aged 4-14 years) serological tests were performed annually.

RESULTS

Using culture as the reference standard, the ELISA tests using the advised cut off values had a sensitivity of 79% and a specificity of 89% for chronic colonisation. Receiver-operator characteristic curves were created to optimise cut off values. Applying these new cut off values resulted in a sensitivity of 96% and a specificity of 79%. All three individual serological tests discriminated well between the absence and presence of chronic P aeruginosa colonisation. The sensitivity of the individual antibody test was 87% for elastase, 79% for exotoxin A, and 76% for alkaline protease. First colonisation was preceded by positive serological results in only five of 13 patients (38%).

CONCLUSION

In patients with CF, serological tests using specific antigens are sensitive for diagnosing chronic P aeruginosa colonisation. However, the failure of serological tests to detect early colonisation in young patients emphasises the need for continued reliance on cultures.

Outcome of assisted ventilation for acute respiratory failure in cystic fibrosis

OBJECTIVES

To assess outcome of assisted ventilation in cystic fibrosis (CF) patients with acute respiratory failure (ARF), to identify risk factors associated with poor outcome and to compare long-term outcome of CF children who were mechanically ventilated for ARF with unventilated CF controls.

DESIGN

Retrospective cohort study.

SETTING

Two large CF centres in the Netherlands.

PATIENTS

CF patients who required assisted ventilation for ARF and unventilated CF controls.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

Thirty-one CF patients required assisted ventilation for ARF between January 1990 and March 2005. All five children (under 2 years of age) and seven adults (27%) survived. In the total population, age was a statistically significant risk factor for poor outcome (p=0.02). In adult CF patients who required invasive mechanical ventilation, acute on chronic respiratory failure was associated with poor outcome. In children who required mechanical ventilation for ARF, lung function and CF related complications 5 years later were not significantly different compared with controls matched for age, gender and genotype.

CONCLUSIONS

CF patients younger than 2 years old, who are ventilated because of ARF, have a good prognosis and their long-term outcome seems identical to unventilated CF controls. ARF in adult CF patients still is associated with high mortality, especially among patients with acute on chronic respiratory failure.

Birth prevalence and survival in cystic fibrosis: a national cohort study in the Netherlands

BACKGROUND

Birth prevalence and survival in patients with cystic fibrosis (CF) in the Netherlands were last investigated > 30 years ago. However, since then the birth prevalence may have decreased because of genetic counseling and an increased number of newborns of non-European descent. Although survival of CF patients has increased worldwide, a significantly lower median age at death was recently reported in the Netherlands compared with data from the United States.

OBJECTIVES

To analyze birth prevalence and survival in CF patients in the Netherlands, and to compare this survival data with US CF data.

DESIGN

Survey of all CF patients living in the Netherlands, and analysis of Dutch CF mortality statistics using data from the Dutch central statistics office, Statistics Netherlands (Voorburg, the Netherlands), and a comparison with Cystic Fibrosis Foundation (Bethesda, MD) patient registry data.

SETTING

All CF centers in the Netherlands and the United States.

PARTICIPANTS

All CF patients treated in the Netherlands on January 1, 2001, and all persons who died of CF between 1974 and 2000, and an equivalent US population.

MEASUREMENTS

Birth prevalence and birth cohort-specific survival.

RESULTS

The overall birth prevalence of CF for 1974 to 1994 was 1 in 4,750 live births, which is a considerable decrease compared with 1961 to 1965 (1 in 3,600 live births). Estimated survival to 30 years increased from 6% in the 1950-to-1954 cohort, to 36% in the 1970-to-1973 cohort. Exact survival could be calculated from 1974 onwards. Survival to 15 years increased from 72% from the 1974-to-1979 cohort, to 91% in the 1985-to-1989 cohort. Survival in the United States in the 1980-to-1984 cohort was better compared to the Netherlands, but this difference has disappeared over subsequent cohorts.

CONCLUSIONS

The actual birth prevalence of CF in the Netherlands is clearly lower than it was 30 years ago. Survival in CF has dramatically improved. The difference in survival between the Netherlands and the United States, as observed in the cohorts born > 20 years ago, has disappeared.

Disease modifying genes in cystic fibrosis

The variation in cystic fibrosis (CF) lung disease and development of CF related complications correlates poorly with the genotype of the CF transmembrane regulator (CFTR) and with environmental factors. Increasing evidence suggests that phenotypic variation in CF can be attributed to genetic variation in genes other than the CFTR gene, so-called modifier genes. In recent years, multiple candidate modifier genes have been investigated in CF, especially genes that are involved in the control of infection, immunity and inflammation. Some of these genes have been rather conclusively identified as modifiers of the CF phenotype, whereas associations found in other genes have not been confirmed or are conflicting. Identification of genetic variation in modifier genes, obtained by genotype-phenotype studies in well-defined patient populations, may be used as an aid to prognosis and may provide the possibility of new therapeutic interventions.

The diagnostic and screening capacities of peak expiratory flow measurements in the assessment of airway obstruction and bronchodilator response in children with asthma

Although the measurement of peak expiratory flow (PEF) is frequently used in general practice as a surrogate for forced expiratory volume in one second (FEV1) in the assessment of airway obstruction and bronchodilator response (BDR), its use has never been validated in children with asthma. Spirometry and PEF measurements (mini-Wright peak flow meter) were performed in 271 children with asthma who attended the hospital for a routine pulmonary evaluation. Airway obstruction was defined as FEV1 as a percentage of predicted (FEV1% pred) < 80%; a positive BDR was defined as an increase in FEV1% pred > or 9% after inhaling 800 micrograms salbutamol. The Spearman correlation coefficient between the percent-predicted values of PEF (PEF% pred) and FEV1% pred was 0.36, Commonly used cut off values for airway obstruction of PEF% pred < 75% and PEF% pred < 80% had a high specificity (95%, 91%) and NPV (95%, 95%), but a moderate sensitivity (54%, 57%) and PPV (54%, 41%). After administration of the bronchodilator, the Spearman correlation coefficient between the different expressions of delta PEF and delta FEV1% pred ranged between 0.52 and 0.54. Commonly used cut off values for BDR of delta PEF% init (increase in PEF as percentage of initial value) > or = 20% and delta PEF% init > or = 25% had a high specificity (96%, 96%), a reasonable NPV (74%, 69%) and PPV (74%, 85%), but a moderate sensitivity (51%, 53%). In conclusion, PEF testing has the properties to be a good screening test to exclude airway obstruction and BDR (high specificity and NPV), but is of less clinical value as a diagnostic test (moderate sensitivity and PPV).