Feasibility study of micronutrient status and body mass index of newly diagnosed pediatric oncology patients: Research commentary

We conducted a feasibility study to evaluate micronutrients and body mass index (BMI). Fat soluble vitamins A, D, E and trace elements copper (Cu), selenium (Se), and zinc (Zn) levels were evaluated. Weight, height, BMI, and Z-scores were recorded. Side effects or specific adverse events were documented. No patient had a Z-score for height, weight, or BMI of less than 2 SD or greater than 2 SD. Ninety percent of patients had one or more micronutrient levels below normal. These results suggest that micronutrient abnormalities are common despite no obvious evidence of malnutrition. Side effects of chemotherapy may be exacerbated by micronutrient depletion.

An 8-Week Virtual Exercise Training Program for Pediatric Solid Organ Transplant Recipients

PURPOSE

Musculoskeletal strength can be impaired in pediatric solid organ transplant recipients. Exercise training programs can be beneficial but in-person delivery can be challenging; virtual exercise programs can alleviate some of these challenges. This feasibility study aimed to deliver an 8-week virtual exercise program in pediatric solid organ transplant recipients.

METHOD

Program delivery occurred 3 times per week for 30 minutes. An exercise stress test was completed prior to program start. The Bruininks-Oseretsky Test of Motor Proficiency strength subtest and self-report surveys were used to assess musculoskeletal strength, quality of life, fatigue, and physical activity. Contact was maintained through a text messaging platform. Z scores were calculated using standardized normative data. Medians (interquartile range) are reported for all other data.

RESULTS

Eleven participants completed the program (2 liver, 5 kidney, 4 heart; 58% females; median age = 11.5 [10.3-13.8] y). Six participants attended ≥60% of classes, 5 participants attended <50% of classes. After 8 weeks, strength scores improved (Z score, Pre: -1.0 [-1.65 to -0.60] to Post: -0.2 [-1.30 to 0.40]; P = .007) with no change in other outcome measures.

CONCLUSION

The virtual exercise program was delivered without technical issues and received positive participant feedback. Engagement and costs need to be considered.

Association between in-line filtration and Type I hypersensitivity reactions in pediatric oncology patients receiving intravenous etoposide

The objective of this study was to describe hypersensitivity reactions with and without the use of in-line filters during intravenous etoposide therapy in pediatric oncology patients. This was a retrospective review of all patients treated in the Division of Oncology/Hematology/Bone Marrow Transplant at British Columbia Children's Hospital with intravenous etoposide between December 1, 2013 and February 1, 2018. Hypersensitivity reactions and anaphylaxis associated with etoposide infusions were compared over time, including 12 months prior to, 27 months during the use of, and for 12 months after the discontinuation of in-line filtration. There were 192 patients (median age 6.0 (IQR 2.8-13.0) years treated with etoposide and 486 etoposide infusions including 137 (28%) before, 261 (54%) during and 88 (18%) after use of in-line filters at our center. Twenty-six of 486 (5%) and 13/486 (3%) of infusions resulted in a type I hypersensitivity reaction and anaphylaxis, respectively. There were 2/137 (1%), 36/261 (14%) and 1/88 (1%) infusion reactions prior to, during and after in-line filter use, respectively. Infusion reactions during the in-line filter period were higher than during the pre-filter (Z = 3.978; p < 0.001) and post-filter (Z = 3.335; p < 0.001) periods of the study. These data suggest that the use of in-line filtration may be associated with increased frequency of hypersensitivity reactions to etoposide in pediatric cancer patients.

Aortic Dimensions, Biophysical Properties, and Plasma Biomarkers in Children and Adults with Marfan or Loeys-Dietz Syndrome

Background

Aortic dilation, stiffening, and dissection are common and potentially lethal complications of Marfan syndrome (MFS) and Loeys-Dietz syndrome (LDS), which involve abnormal transforming growth factor beta (TGF-β) signalling. The relation of aortic dimensions, stiffness, and biomarker levels is unknown. The objective of this study was to measure aortic dimensions, stiffness, TGF-β and matrix metalloproteinase (MMP) levels, and endothelial function in patients with MFS, and to compare TGF-β levels in patients with MFS receiving different therapeutic regimens.

Methods

This was a cohort study of 40 MFS and 4 LDS patients and 87 control participants. Aortic dimension and stiffness indexes, including pulse wave velocity (PWV), were measured using echocardiography and Doppler. Total and free TGF-β and MMP blood levels were measured using Quantikine (R&D Systems, Inc, Minneapolis, MN) and Quanterix (Billerica, MA) kits. Endothelial function was measured using brachial artery flow-mediated dilation.

Results

PWV was increased in patients with MFS. There were increased MMP-2 levels in those with MFS but no increase in free or total TGF-β or MMP-9 levels compared with control participants. There was no difference in TGF-β levels between MFS patients receiving no medications, angiotensin receptor blockers, and β-blockers. PWV correlated most strongly with age. Endothelial function showed premature gradual decline in patients with MFS.

Conclusions

Despite the increased PWV, monitoring aortic stiffness or TGF-β levels would not be helpful in patients with MFS. TGF-β levels were not increased and the increased MMP-2 levels suggest consideration of a different therapeutic target.

Physiological Responses to Exercise in Pediatric Heart Transplant Recipients

INTRODUCTION

Pediatric heart transplant (HTx) recipients have reduced exercise capacity typically two-thirds of predicted values, the mechanisms of which are not fully understood. We sought to assess the cardiorespiratory responses to progressive exercise in HTx relative to controls matched for age, sex, body size, and work rate.

METHODS

Fourteen HTx recipients and matched controls underwent exercise stress echocardiography on a semisupine cycle ergometer. Hemodynamics, left ventricular (LV) dimensions, and volumes were obtained and indexed to body surface area. Oxygen consumption (V˙O2) was measured, and arteriovenous oxygen difference was estimated using the Fick Principle.

RESULTS

At rest, LV mass index (P = 0.03) and volumes (P < 0.001) were significantly smaller in HTx, whereas wall thickness (P < 0.01) and LV mass-to-volume ratio (P = 0.01) were greater. Differences in LV dimensions and stroke volume persisted throughout exercise, but the pattern of response was similar between groups as HR increased. As exercise progressed, heart rate and cardiac index increased to a lesser extent in HTx. Despite this, V˙O2 was similar (P = 0.82) at equivalent work rates as HTx had a greater change in arteriovenous oxygen difference (P < 0.01).

CONCLUSIONS

When matched for work rate, HTx had similar metabolic responses to controls despite having smaller LV chambers and an attenuated increase in hemodynamic responses. These findings suggest that HTx may increase peripheral O2 extraction as a compensatory mechanism in response to reduced cardiovascular function.

P681Acute Myocardial Infarction in patients with Leukaemia: A national analysis of prevalence, predictors and outcomes in United States hospitalisations (2004 to 2014)

Background

Patients with leukaemia are at increased risk of cardiovascular events. There is limited outcomes data for patients with a history of leukaemia who present with an acute myocardial infarction (AMI).

Purpose

To examine the prevalence and clinical characteristics of patients with leukaemia presenting with AMI, and evaluate differences in clinical outcomes according to the subtype of leukaemia in comparison to patients without leukaemia.

Methods

We analysed the Nationwide Inpatient Sample (2004–2014) for patients with a primary discharge diagnosis of AMI and concomitant leukaemia, and further stratified according to the subtype of leukaemia into 4 groups; AML; ALL; CML; and CLL. Multiple logistic regression was conducted to identify the association between leukaemia and major acute cardiovascular and cerebrovascular events (MACCE; composite of mortality, stroke and cardiac complications) and bleeding.

Results

Out of 6,750,927 AMI admissions, a total of 21,694 patients had a leukaemia diagnosis. The leukaemia group experienced higher rates of MACCE (11.8% vs. 7.8%), mortality (10.3% vs. 5.8%) and bleeding (5.6% vs. 5.3%). Following adjustments, leukaemia was independently associated with increased odds of MACCE (OR 1.26 [1.20,1.31]) and mortality (OR 1.43 [1.37,1.50]) without an increased risk of bleeding (OR 0.86 [0.81,0.92]). Acute myeloid leukaemia (AML) was associated with approximately three-fold risk of MACCE (RR 2.81 [2.51, 3.13]) and a four-fold risk of mortality (RR 3.75 [3.34, 4.22]) (Figure 1). Patients with leukaemia were less likely to undergo coronary angiography (CA) (48.5% vs. 64.5%) and percutaneous coronary intervention (PCI) (28.2% vs. 42.9%) compared to those without leukaemia.

Figure 1.Relative risk of adverse events

Conclusion

Patients with leukaemia, especially those with AML, are associated with poor clinical outcomes after AMI, and are less likely to receive CA and PCI compared to those without leukaemia. A multi-disciplinary approach between cardiologists and haematology oncologists may improve the outcomes of patients with leukaemia after AMI.

The relative incidence of cardiogenic and septic shock in neonates

Objective

To evaluate the relative incidence of cardiogenic and septic shock in term neonates and identify findings that help differentiate the two entities.

Study Design

We conducted a retrospective chart review of term neonates presenting to British Columbia Children's Hospital (BCCH) with decompensated shock of an undiagnosed etiology between January 1, 2008 and January 1, 2013. Charts were reviewed to determine the underlying diagnoses of all neonates meeting our inclusion criteria. Patients were categorized as having septic, cardiogenic, or other etiologies of shock. We then evaluated potential demographic, clinical, and biochemical parameters that could help differentiate between septic and cardiogenic shock.

Results

Cardiogenic shock was more common than septic shock (relative risk=1.53). A history of cyanosis was suggestive of cardiogenic shock (positive likelihood ratio, LR+=3.2 and negative likelihood ratio, LR-=0.4). Presence of a murmur or gallop (LR+=5.4, LR-=0.3), or decreased femoral pulses (LR+=5.1, LR-=0.5) on physical exam were also suggestive of cardiogenic shock as was cardiomegaly on chest x-ray (LR+=4.9, LR-=0.5). Notably, temperature instability (LR+=0.7, LR-=1.8) and white blood cell count elevation or depression (LR+=0.8, LR-=1.1) were all poor predictors of septic shock.

Conclusion

Cardiogenic shock is a more common cause of decompensated shock than septic shock. A history of cyanosis, murmur or gallop, or decreased femoral pulses on exam and cardiomegaly on chest x-ray are useful indicators of cardiogenic shock. In evaluating the neonate with decompensated shock, early consideration for Cardiology consultation and interventions to treat the underlying condition is warranted.

Non-invasive assessment of aortic stiffness and blood pressure in young Turner syndrome patients

Background Females with Turner syndrome (TS) carry an elevated risk of aortic dissection. The objective of the study was to assess the biophysical properties of the aorta and ambulatory blood pressure (BP) in females with TS and compare these findings to those in healthy female age-matched controls. Methods This was a prospective cohort study including subjects aged 8-25 years. Utilizing two-dimensional (2D) echocardiography and Doppler, proximal aortic dimensions were measured and biophysical properties of the aorta were calculated including pulse wave velocity (PWV), arterial pressure-strain elastic modulus and stiffness index. Resting BP was measured and ambulatory blood pressure monitoring (ABPM) was performed. Results Of 23 TS patients and 46 controls (median age 16.3 years), aortic annulus, sinus of Valsalva and sinotubular (ST) junction diameters, as well as left ventricular (LV) mass, were significantly greater in TS patients compared with controls when scaled for height2.7, but not for body surface area (BSA), although ascending aorta diameter was greater when scaled for both. Median PWV was faster in TS patients compared to controls (451 vs. 360 cm/s) while arterial pressure-strain elastic modulus and stiffness index were similar. Resting BP was abnormal in seven out of 22 patients and ABPM was abnormal in 16 out of 21 patients. Conclusions Young patients with TS had dilated proximal aortas when scaled for height2.7 and stiffer aortas when compared with healthy female age-matched controls. Moreover, resting BP underdiagnosed pre-hypertension and hypertension compared to ABPM. These findings are consistent with the presence of a primary aortopathy in TS.

Echocardiographic Assessment of Ventricular Function During Exercise in Adolescent Female Patients With Anorexia Nervosa

BACKGROUND

Patients with anorexia nervosa (AN) have altered physiologic responses to exercise. The aim of this study was to investigate exercise capacity and ventricular function during exercise in adolescent patients with AN.

METHODS

Sixty-six adolescent female patients with AN and 21 adolescent female control subjects who exercised to volitional fatigue on a semisupine ergometer, using an incremental step protocol of 20 W every 3 min, were retrospectively studied. Heart rate, blood pressure, and echocardiographic Doppler indices were measured at rest and during each stage of exercise. Fractional shortening, rate-corrected mean velocity of circumferential fiber shortening, stress at peak systole, cardiac output, and cardiac index were calculated. Minute ventilation, oxygen consumption, carbon dioxide production, and respiratory exchange ratio were measured using open-circuit spirometry.

RESULTS

Patients with AN had significantly lower body mass index (16.7 vs 19.7 kg/m², P < .001), total work (1,126 vs 1,914 J/kg, P < .001), and test duration (13.8 vs 20.8 min, P < .001) compared with control subjects. Peak minute ventilation, oxygen consumption, and carbon dioxide production were significantly decreased in patients with AN. Heart rate, systolic blood pressure, cardiac index, fractional shortening, and rate-corrected mean velocity of circumferential fiber shortening demonstrated similar patterns of increase with progressive exercise between groups but were decreased at peak exercise in patients with AN. Body mass index percentile, age, peak oxygen consumption, and peak cardiac output were independently associated with exercise duration.

CONCLUSIONS

Adolescent patients with AN have reduced exercise capacity and peak cardiovascular indices compared with control subjects but normal patterns of cardiovascular response during progressive exercise. Systolic ventricular function is maintained during exercise in adolescents with AN.

The clinical and genetic spectrum of catecholaminergic polymorphic ventricular tachycardia: findings from an international multicentre registry

Aims

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an ion channelopathy characterized by ventricular arrhythmia during exertion or stress. Mutations in RYR2-coded Ryanodine Receptor-2 (RyR2) and CASQ2-coded Calsequestrin-2 (CASQ2) genes underlie CPVT1 and CPVT2, respectively. However, prognostic markers are scarce. We sought to better characterize the phenotypic and genotypic spectrum of CPVT, and utilize molecular modelling to help account for clinical phenotypes.

Methods and results

This is a Pediatric and Congenital Electrophysiology Society multicentre, retrospective cohort study of CPVT patients diagnosed at <19 years of age and their first-degree relatives. Genetic testing was undertaken in 194 of 236 subjects (82%) during 3.5 (1.4-5.3) years of follow-up. The majority (60%) had RyR2-associated CPVT1. Variant locations were predicted based on a 3D structural model of RyR2. Specific residues appear to have key structural importance, supported by an association between cardiac arrest and mutations in the intersubunit interface of the N-terminus, and the S4-S5 linker and helices S5 and S6 of the RyR2 C-terminus. In approximately one quarter of symptomatic patients, cardiac events were precipitated by only normal wakeful activities.

Conclusion

This large, multicentre study identifies contemporary challenges related to the diagnosis and prognostication of CPVT patients. Structural modelling of RyR2 can improve our understanding severe CPVT phenotypes. Wakeful rest, rather than exertion, often precipitated life-threatening cardiac events.

Catecholaminergic polymorphic ventricular tachycardia patients with multiple genetic variants in the PACES CPVT Registry

BACKGROUND

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is often a life-threatening arrhythmia disorder with variable penetrance and expressivity. Little is known about the incidence or outcomes of CPVT patients with ≥2 variants.

METHODS

The phenotypes, genotypes and outcomes of patients in the Pediatric and Congenital Electrophysiology Society CPVT Registry with ≥2 variants in genes linked to CPVT were ascertained. The American College of Medical Genetics & Genomics (ACMG) criteria and structural mapping were used to predict the pathogenicity of variants (3D model of pig RyR2 in open-state).

RESULTS

Among 237 CPVT subjects, 193 (81%) had genetic testing. Fifteen patients (8%) with a median age of 9 years (IQR 5-12) had ≥2 variants. Sudden cardiac arrest occurred in 11 children (73%), although none died during a median follow-up of 4.3 years (IQR 2.5-6.1). Thirteen patients (80%) had at least two RYR2 variants, while the remaining two patients had RYR2 variants plus variants in other CPVT-linked genes. Among all variants identified, re-classification of the commercial laboratory interpretation using ACMG criteria led to the upgrade from variant of unknown significance (VUS) to pathogenic/likely pathogenic (P/LP) for 5 variants, and downgrade from P/LP to VUS for 6 variants. For RYR2 variants, 3D mapping using the RyR2 model suggested that 2 VUS by ACMG criteria were P/LP, while 2 variants were downgraded to likely benign.

CONCLUSIONS

This severely affected cohort demonstrates that a minority of CPVT cases are related to ≥2 variants, which may have implications on family-based genetic counselling. While multi-variant CPVT patients were at high-risk for sudden cardiac arrest, there are insufficient data to conclude that this genetic phenomenon has prognostic implications at present. Further research is needed to determine the significance and generalizability of this observation. This study also shows that a rigorous approach to variant re-classification using the ACMG criteria and 3D mapping is important in reaching an accurate diagnosis, especially in the multi-variant population.

Does competitive swimming affect lung growth?

Whether the large lungs of swimmers result from intensive training or genetic endowment has been widely debated. Given that peak lung growth velocities occur during puberty, this study examined if competitive swimming during puberty affected lung growth. Eleven- to fourteen-year-old healthy female competitive swimmers and controls were assessed before (PRE) and after (POST) one swimming season (7.4 ± 0.5 months). Pulmonary function testing included lung volumes, spirometry, diffusion capacity (DL,CO ), and maximal inspiratory (PIMAX ) and expiratory (PEMAX ) pressures. Ventilatory constraints, including end-expiratory lung volume, expiratory flow limitation, and utilization of ventilatory capacity, were assessed during an incremental cycling test. Swimmers (n = 11) and controls (n = 10) were of similar age, size, and sexual maturity (P > 0.05). However, swimmers compared to controls had a greater total lung capacity (PRE 4.73 ± 0.73 vs. 3.93 ± 0.46, POST 5.08 ± 0.68 vs. 4.19 ± 0.64 L; P < 0.01), peak expiratory flow (PRE 6.48 ± 0.92 vs. 5.70 ± 0.86, POST 6.97 ± 0.84 vs. 6.00 ± 0.77 L·s-1 ; P = 0.03), and PEMAX (P < 0.001). Although DL,CO was greater in swimmers (P = 0.01), differences were attenuated when expressed relative to alveolar volume (PRE 5.14 ± 0.60 vs. 5.44 ± 0.44, POST 4.91 ± 0.56 vs. 5.16 ± 0.38 mL min-1  mmHg-1  L-1 ; P = 0.20). The groups achieved a similar maximal oxygen uptake (P = 0.32), and ventilatory constraints experienced were not different (P > 0.05). Changes over time were not different between groups (P > 0.05). At the initial measurement, pubertal female swimmers had greater lung size, expiratory flows, and indices of respiratory muscle strength, but similar ventilatory constraints while cycling. One competitive swimming season did not further accentuate this enhanced lung size and function or alter ventilatory mechanics, suggesting that competitive swimming during puberty did not affect lung growth.

Doppler Echocardiography Assessment of Aortic Stiffness in Female Adolescents with Anorexia Nervosa

BACKGROUND

Anorexia nervosa (AN) is associated with abnormalities in biomarkers of cardiovascular risk. Arterial stiffness, as measured by pulse-wave velocity (PWV), is also a risk factor for cardiovascular disease. The aims of this study were to determine the stiffness of the aorta in female adolescents with AN and to determine if either the severity or the type of AN was associated with PWV.

METHODS

This was a retrospective case-control study. Adolescent patients with a clinical diagnosis of AN were included. Aortic diameter and pulse-wave transit time over a portion of the thoracic aorta were measured using Doppler echocardiography, and PWV was calculated.

RESULTS

There were 94 female patients with AN and 60 adolescent female control subjects. There was no significant difference in age between patients with AN and control subjects (15.5 ± 1.7 vs 15.1 ± 2.6 years, P = .220). Body mass index (16.0 ± 2.4 vs 19.7 ± 2.7 kg/m², P < .001) and body mass index percentile (9.4 ± 15.6 vs 45.5 ± 26.2, P < .001) were significantly lower for patients with AN than control subjects. PWV (443 ± 106 vs 383 ± 77 cm/sec, P < .001) was significantly higher in patients with AN than control subjects. Similar differences from control subjects were found in patients with AN with both lower and higher body mass index percentiles and also in patients with AN with the restrictive or the binge-purge subtype.

CONCLUSIONS

Female adolescents with AN have increased aortic stiffness compared with control subjects. This study suggests that patients with AN may be at increased risk for future cardiovascular disease. Future studies are required to determine the reversibility of these changes with weight restoration.

A Doppler Echocardiographic Study of the Myocardial Inotropic Response to Peak Semisupine Exercise in Healthy Children: Development of a Simplified Index of Myocardial Reserve

BACKGROUND

Stress echocardiography has been advocated for the detection of abnormal myocardial function and unmasking diminished myocardial reserve in pediatric patients. The aim of this study was to create a simplified index of myocardial reserve, derived from the myocardial inotropic response to peak semisupine exercise in healthy children, and illustrate its applicability in a sample of pediatric oncology patients.

METHODS

In this prospective analysis, children (7-18 years of age) with normal cardiac structure and function performed semisupine stress echocardiography to volitional fatigue. The quotient of wall stress at peak systole and heart rate-corrected velocity of circumferential fiber shortening were calculated at baseline and at peak exercise, the difference of which was termed the index of myocardial reserve (IMR). The IMR was also calculated in a retrospective sample of pediatric oncology patients with normal resting left ventricular function who had received anthracycline treatment and had performed the same exercise protocol to illustrate utility.

RESULTS

Fifty healthy subjects (mean age, 13.2 ± 2.6 years) and 33 oncology patients (mean age, 12.7 ± 4.0 years) were assessed. In the healthy children at peak exercise, heart rate-corrected velocity of circumferential fiber shortening significantly increased (from 1.17 ± 0.17 to 1.58 ± 0.24 circ · sec^-1, P < .001), while the quotient of wall stress at peak systole significantly decreased (from 75.3 ± 17.1 to 55.3 ± 13.8 g · cm^-2, P < .001), shifting the plot of the relationship between the two parameters upward and to the left. The mean IMR was -30.8 ± 17.8, and the normal distribution ranged from -4.7 (fifth percentile) to -67.3 (95th percentile). The IMR was abnormal in 10 oncology patients who were treated with anthracyclines.

CONCLUSIONS

The authors have developed a novel IMR. Relative to the normal distribution of this IMR in healthy subjects, it is possible to identify patients with abnormal myocardial reserve. Thus, this study demonstrates the application of the IMR to aid in clinical decision making in individual patients.

A novel treadmill protocol for exercise testing in children: the British Columbia Children's Hospital protocol

BACKGROUND

Exercise testing in children is widely recommended for a number of clinical and prescriptive reasons. Many institutions continue to use the Bruce protocol for treadmill testing; however, with its incremental changes in speed and grade, it has challenges for practical application in children. We have developed a novel institutional protocol (British Columbia Children's Hospital (BCCH)), which may have better utility in paediatric populations.

AIM

To determine if our institutional protocol yields similar peak responses in minute ventilation (VE), oxygen consumption (VO2), carbon dioxide production (VCO2), respiratory exchange ratio (RER), metabolic equivalents (METS) and heart rate (HR) when compared with the traditional Bruce protocol.

METHODS

On two different occasions, 70 children (boys=33; girls=37) aged 10-18 years completed an exercise test on a treadmill using each of the protocols. During each test, metabolic gas exchange parameters were measured. HR was monitored continuously during exercise using an HR monitor.

RESULTS

Physiological variables were similar between the two protocols (median (IQR); rs): VE (L/min) (BCCH=96.7 (72.0-110.2); Bruce=99.2 (75.6-120.0); rs=0.95), peak VO2 (mL/min) (BCCH=2897 (2342-3807); Bruce=2901 (2427-3654); rs=0.94) and METS (BCCH=16.2 (14.8-17.7); Bruce=16.4 (14.7-17.9); rs=0.89). RERs were similar (BCCH=1.00 (0.96-1.02); Bruce=1.03 (0.99-1.07); rs=0.48). Total exercise time (in seconds) was longer for the BCCH protocol: BCCH=915 (829-1005); Bruce=810 (750-919); rs=0.67.

CONCLUSION

The BCCH protocol produces similar peak exercise responses to the Bruce protocol and provides an alternative for clinical exercise testing in children.

Exercise and the multidisciplinary holistic approach to adolescent dysautonomia

AIM

To determine whether an eight-week strength training programme as part of a multidisciplinary approach would minimise symptoms and improve quality of life in patients with dysautonomia.

METHODS

Adolescents referred to a tertiary-level cardiology service from May 2014-December 2015 with symptoms of dysautonomia were eligible. Participants completed an exercise test and a quality of life (QoL) questionnaire (PedsQL) prior to the intervention. Participants were asked to complete exercises five times per week. After eight weeks, participants returned for follow-up testing. Parents completed a proxy report of their child's QoL at both time points.

RESULTS

A total of 17 participants completed the study protocol with an adherence rate of up to 50%. Post-intervention, QoL scores improved across all levels in the participants [total 65.2 (50.4-74.7) vs 48.9 (37.5-63.0); p = 0.006; psychosocial 65.8 (56.1-74.6) vs 50.0 (41.7-65.8); p = 0.010; physical 62.5 (37.5-76.6) vs 43.8 (25-68.5); p = 0.007] and their parent proxy reports [total 63.5 (48.7-81.3) vs 50.0 (39.3-63.0); p = 0.004; psychosocial 62.1 (52.1-81.3) vs 50.0 (39.6-59.2); p = 0.001; physical 62.5 (51.6-80.0) vs 50.0 (27.5-70.3); p = 0.003]. Treadmill time also improved (9.1 vs 8.0 minutes; p = 0.005).

CONCLUSION

Following an eight-week strength training programme, dysautonomia patients report a significant improvement in both their quality of life and endurance time.

Stress Echocardiographic Evaluation for D-Transposition of the Great Arteries after Atrial Redirection: Unmasking Early Signs of Myocardial Dysfunction and Baffle Stenosis

BACKGROUND

The authors used semisupine cycle ergometry stress echocardiography to assess cardiac function and unmask baffle stenosis in patients with d-transposition of the great arteries after atrial redirection surgery.

METHODS

This was a retrospective review of semisupine cycle ergometry stress echocardiography performed in 53 patients (64% male; mean age, 24.0 years; 90% Mustard procedure) and 56 healthy control subjects. Incremental exercise to volitional fatigue was performed. Hemodynamic data, echocardiographic cardiac dimensions, area change, tissue Doppler velocities, strain, ventricular synchronization, and superior vena cava flow velocities before and immediately after exercise are reported.

RESULTS

Patients had lower exercise capacity (870 vs 1,854 J/kg, P < .001) and peak heart rates (132 vs 167 beats/min, P < .001). Stroke volume index did not increase with exercise (45 vs 47 mL/m², P = .400). Cardiac index increased in both groups with exercise (3.0 vs 6.1 and 2.9 vs 7.0 L/min/m², P < .001) and was higher in control subjects (P = .006). Right ventricular diastolic and systolic areas decreased significantly with exercise in both the short-axis and four-chamber views. Right and left ventricular contraction time shortened with exercise (405 vs 247 and 338 vs 217 msec, P < .001) and remained synchronous (ratio of right ventricular to left ventricular contraction time = 0.080). Doppler velocities in patients with baffle obstruction were higher in the lower superior vena cava with exercise compared with nonobstructed patients (1.87 vs 1.46 m/sec, P = .020) and normalized after catheter intervention (1.49 vs 1.46 m/sec, P = .800).

CONCLUSIONS

Patients with d-transposition of the great arteries have lower exercise capacity and peak heart rates. The systemic right ventricle presents a lesser but qualitatively normal systolic response and decreased diastolic filling. Semisupine cycle ergometry stress echocardiography unmasked SVC obstruction.

Predictors of poor outcome among children with heterotaxy syndrome: a retrospective review

Objective

To determine predictors of poor outcome in patients with heterotaxy syndrome.

Methods

A retrospective review of children with heterotaxy syndrome, in a single tertiary paediatric cardiology centre, was conducted between 1 January 1997 and 1 January 2014 to determine predictors of poor outcome. Poor outcome was defined as death, cardiac transplantation or New York Heart Association (NYHA) functional class III or IV.

Results

There were 35 patients diagnosed with heterotaxy syndrome, 17 of whom were diagnosed antenatally. 22 patients had right atrial isomerism and 13 had left atrial isomerism. The median age of postnatal diagnosis was 2.5 days old (1 day to 19 months). 12 patients had a poor outcome; 6 patients died, 1 underwent cardiac transplantation and 5 had an NYHA functional class of >III. 5 patients had a biventricular repair and the remaining 30 had a univentricular repair. Type of atrial isomerism, univentricular or biventricular anatomy, severity of atrioventricular valve regurgitation or ventricular dysfunction, obstructed pulmonary venous return, occurrence of arrhythmia and presence of pulmonary atresia did not predict poor outcome. Fetal diagnosis also did not confer a survival advantage. The median duration of follow-up in this cohort was 65 months (2 days to 16.8 years).

Conclusions

Survival for patients with heterotaxy syndrome was 83% over a median follow-up of 65 months. 34% of patients had a poor outcome. None of the variables studied were predictive of death, transplantation or NYHA classification III or IV.

Noninvasive Assessment of Vascular Function in Postoperative Cardiovascular Disease (Coarctation of the Aorta, Tetralogy of Fallot, and Transposition of the Great Arteries)

Using noninvasive techniques, we sought to assess arterial stiffness, impedance, hydraulic power, and efficiency in children with postoperative tetralogy of Fallot (TOF), coarctation of the aorta (COA), and transposition of the great arteries (TGAs). Results were compared with those of healthy peers. Fifty-five children with repaired congenital heart disease (24 TOFs, 20 COAs, and 11 TGAs) were compared with 55 age-matched control subjects (CTRL). Echocardiographic Doppler imaging and carotid artery applanation tonometry were preformed to measure aortic flow, dimensions, and calculate pulse wave velocity, vascular impedance and arterial stiffness indexes, hydraulic power (mean and total), and hydraulic efficiency (HE) which were calculated using standard fluid dynamics equations. All congenital heart disease subgroups had higher pulse wave velocity than CTRL. Only the COA group had higher characteristic impedance. Mean power was higher in TGA than in CTRL and TOF, and total power was higher in TGA than in CTRL and TOF. Hydraulic efficiency was higher in TOF than in COA and TGA. In conclusion, children with TOF, COA, and TGA have stiffer aortas than CTRL. These changes may be related to intrinsic aortic abnormalities, altered integrity of the aorta due to surgical repair, and/or acquired postsurgery. These patients may be at increased long-term cardiovascular risk, and long-term follow-up is important for monitoring and assessment of efforts to reduce risk.

Characterization of Myocardial Repolarization Reserve in Adolescent Females With Anorexia Nervosa

BACKGROUND

Patients with anorexia nervosa exhibit abnormal myocardial repolarization and are susceptible to sudden cardiac death. Exercise testing is useful in unmasking QT prolongation in disorders associated with abnormal repolarization. We characterized QT adaptation during exercise in anorexia.

METHODS AND RESULTS

Sixty-one adolescent female patients with anorexia nervosa and 45 age- and sex-matched healthy volunteers performed symptom-limited cycle ergometry during 12-lead ECG monitoring. Changes in the QT interval during exercise were measured, and QT/RR-interval slopes were determined by using mixed-effects regression modeling. Patients had significantly lower body mass index than controls; however, resting heart rates and QT/QTc intervals were similar at baseline. Patients had shorter exercise times (13.7±4.5 versus 20.6±4.5 minutes; P<0.001) and lower peak heart rates (159±20 versus 184±9 beats/min; P<0.001). The mean QTc intervals were longer at peak exercise in patients (442±29 versus 422±19 ms; P<0.001). During submaximal exertion at comparable heart rates (114±6 versus 115±11 beats/min; P=0.54), the QTc interval had prolonged significantly more in patients than controls (37±28 versus 24±25 ms; P<0.016). The RR/QT slope, best described by a curvilinear relationship, was more gradual in patients than in controls (13.4; 95% confidence interval, 12.8-13.9 versus 15.8; 95% confidence interval, 15.3-16.4 ms QT change per 10% change in RR interval; P<0.001) and steepest in patients within the highest body mass index tertile versus the lowest (13.9; 95% confidence interval, 12.9-14.9 versus 12.3; 95% confidence interval, 11.3-13.3; P=0.026).

CONCLUSIONS

Despite the absence of manifest QT prolongation, adolescent anorexic females have impaired repolarization reserve in comparison with healthy controls. Further study may identify impaired QT dynamics as a risk factor for arrhythmias in anorexia nervosa.

Catecholaminergic polymorphic ventricular tachycardia in children: analysis of therapeutic strategies and outcomes from an international multicenter registry

BACKGROUND

Catecholaminergic polymorphic ventricular tachycardia is an uncommon, potentially lethal, ion channelopathy. Standard therapies have high failure rates and little is known about treatment in children. Newer options such as flecainide and left cardiac sympathetic denervation are not well validated. We sought to define treatment outcomes in children with catecholaminergic polymorphic ventricular tachycardia.

METHODS AND RESULTS

This is a Pediatric and Congenital Electrophysiology Society multicenter, retrospective cohort study of catecholaminergic polymorphic ventricular tachycardia patients diagnosed before 19 years of age. The cohort included 226 patients, including 170 probands and 56 relatives. Symptomatic presentation was reported in 176 (78%). Symptom onset occurred at 10.8 (interquartile range, 6.8-13.2) years with a delay to diagnosis of 0.5 (0-2.6) years. Syncope (P<0.001), cardiac arrest (P<0.001), and treatment failure (P=0.008) occurred more often in probands. β-Blockers were prescribed in 205 of 211 patients (97%) on medication, and 25% experienced at least 1 treatment failure event. Implantable cardioverter defibrillators were placed in 121 (54%) and was associated with electrical storm in 22 (18%). Flecainide was used in 24% and left cardiac sympathetic denervation in 8%. Six deaths (3%) occurred during a cumulative follow-up of 788 patient-years.

CONCLUSIONS

This study demonstrates a malignant phenotype and lengthy delay to diagnosis in catecholaminergic polymorphic ventricular tachycardia. Probands were typically severely affected. β-Blockers were almost universally initiated; however, treatment failure, noncompliance and subtherapeutic dosing were often reported. Implantable cardioverter defibrillators were common despite numerous device-related complications. Treatment failure was rare in the quarter of patients on flecainide. Left cardiac sympathetic denervation was not uncommon although the indication was variable.

Current Management of Focal Atrial Tachycardia in Children

Background—

Focal atrial tachycardia (FAT) is an uncommon cause of supraventricular tachycardia in children. Incessant FAT can lead to tachycardia-induced cardiomyopathy. There is limited information regarding the clinical course and management of FAT. This study characterizes current management strategies for FAT in children including the prevalence of spontaneous resolution and the role of catheter ablation.

Methods and Results—

This is a retrospective chart review of pediatric patients with FAT managed between January 2000 and November 2010 at 10 pediatric centers. There were 249 patients with a median age at diagnosis of 7.2 (95% confidence interval, 5.8–10.4) years. Cardiomyopathy was observed in 28%. Resolution of FAT occurred in 89%, including spontaneous resolution without catheter ablation in 34%. Antiarrhythmic medications were used for initial therapy in 154 patients with control of FAT in 72%. Among first-line medications, β-blockers were the most common (53%) and effective (42%). Catheter ablation was successful in 80% of patients. FAT recurrence was less common with electroanatomic mapping compared with conventional mapping techniques (16% versus 35%; P =0.02). Patients were followed for a median of 2.1 (95% confidence interval, 1.8–2.6) years.

Conclusions—

FAT is managed successfully in most children. Current approaches are variable. Many patients have control of FAT with medications; however, catheter ablation is used for most patients. Spontaneous resolution is common for young children, emphasizing the role for delayed ablation in this group. Ablation is successful for all ages. Lower recurrence occurs when electroanatomic mapping techniques are used.

Feasibility of Optical Coherence Tomography in Children With Kawasaki Disease and Pediatric Heart Transplant Recipients

Background—

Optical coherence tomography (OCT) is a high-resolution intravascular imaging technique used in adults. We tested the hypothesis that OCT could identify coronary abnormalities not seen by angiography in children with a history of Kawasaki disease (KD) and pediatric heart transplant (TX) recipients.

Methods and Results—

Patients with KD and TX recipients were evaluated between December 2012 and October 2013 with angiography and OCT (Ilumien System, LightLabs, St Jude Medical, Westford, MA). Modifications were made to the adult OCT protocol to adapt this technique for children. Serial cross-sectional area measurements of the lumen, intima, and media were made. Entire imaging data were analyzed for the presence of qualitative changes. Seventeen children were evaluated (5 patients with KD; 12 TX recipients). In patients with KD, angiography was normal. However, OCT imaging revealed that significant vessel wall abnormalities were present in all children including intimal thickening (intima/lumen cross-sectional area ratio>0.4), loss of the normal layered structure of the vessel wall, white thrombus, calcification, and neovascularization. There was extensive destruction of the internal elastic lamina. In TX recipients, angiography was normal; however, intimal thickening (intima/media cross-sectional area ratio>1) was seen in 9 of 12 patients. The median intima/media cross-sectional area ratio was 1.18.

Conclusions—

In this initial experience with OCT in children, we have identified significant coronary abnormalities with OCT that are angiographically silent in children with a history of coronary aneurysms because of KD and in pediatric TX recipients.

Minimally invasive approach to the child with palpitations

Palpitations are a common reason for referral to a pediatric cardiologist. Although generally benign, palpitations are a significant cause for concern in the individual and their family. Similarly, palpitations may be the initial presentation of significant heart disease, resulting in heightened concern in the referring physician. Although emphasis is usually placed on excluding arrhythmia as the cause for palpitations, there are a variety of noncardiac causes for palpitations. The patient history and physical examination are the key components of the evaluation and guide subsequent investigations. In many cases, an immediate diagnosis cannot be made and additional testing may be required; this often includes further monitoring for episodes, cardiac imaging and ambulatory monitoring. Current technologies for ambulatory monitoring during symptoms include Holter monitoring and a variety of patient-activated event recorders, including implantable loop recorders. Each presents its own unique advantages and disadvantages to aid diagnosis in the management of a child with palpitations. The primary focus for the clinician is to determine whether the etiology is benign in nature or whether there is underlying heart disease that may carry a more serious prognosis.

Physical activity recommendations for patients with electrophysiologic and structural congenital heart disease: a survey of Canadian health care providers

Determining safe levels of physical activity for children and adolescents with electrophysiologic and structural congenital heart disease is a challenging clinical problem. The body of evidence for making these recommendations is limited and likely based on expert opinion, medicolegal concerns, and perceived risks of sudden cardiac death (SCD) with activity. The Bethesda Conference has established consensus guidelines for determining the eligibility of athletes with cardiovascular abnormalities for competitive sports and their disqualification from them. However, literature on guidelines for noncompetitive physical activity is not available. A survey was designed to determine practice patterns for patients with electrophysiologic and structural congenital heart disease. Between July 2011 and December 2011, approximately 350 health care providers working with this group of patients were recruited by email or while attending professional meetings. The survey received 81 responses, primarily from pediatric cardiologists (70 %). The findings indicate that the majority of Canadian cardiac care providers surveyed are only partially implementing current recommendations. Areas of variance included physical activity recommendations for hypertrophic cardiomyopathy, long QT syndrome, catecholaminergic polymorphic ventricular tachycardia, and heart transplantation, among others. The development of comprehensive consensus guidelines for activity recommendations was supported by 96 % of the respondents. The heterogeneity of responses may be attributable to conflicting and poorly evidenced information in the literature, a lack of emphasis on recreational activity, an entrenched tendency toward bed rest in the cardiology community, and a lack of awareness by cardiac care providers regarding the actual risk associated with physical activity in electrophysiologic and structural congenital heart disease. A balanced discussion is required in considering both the significant benefit of physical activity in reducing cardiovascular risk factors and the small possibility of SCD in children and young adults with electrophysiologic and structural congenital heart disease.

Echo-Doppler assessment of the biophysical properties of the aorta in children with chronic kidney disease

Chronic kidney disease (CKD) is known to cause increased arterial stiffness, which is an important independent risk factor for adverse cardiovascular events. The purpose of this study was to assess the vascular properties of the aorta (AO) in a group of children with CKD using a noninvasive echocardiography (echo)-Doppler method. We studied 24 children with stages 2 through 5 CKD and 48 age-matched controls. Detailed echocardiographic assessment and echo-Doppler pulse wave velocity (PWV) was performed. Indices of arterial stiffness, including characteristic (Zc) and input (Zi) impedances, elastic pressure-strain modulus (Ep), and arterial wall stiffness index, were calculated. CKD patients underwent full nephrology assessment, and an iohexol glomerular filtration rate was performed, which allowed for accurate assignment of the CKD stage. CKD patients had greater median systolic blood pressure (114 vs. 110 mmHg; p < 0.04) and pulse pressure (51 vs. 40 mmHg; p < 0.001) compared with controls. PWV was similar between groups (358 vs. 344 cm s(-1); p = 0.759), whereas Zi (182 vs. 131 dyne s cm(-5); p < 0.001), Zc (146 vs. 138 dyne s cm(-5); p = 0.05), and Ep (280 vs. 230 mmHg; p < 0.02) were significantly greater in CKD than in controls. Although load-dependent measures of arterial stiffness were greater in non-dialysis dependent CKD patients, PWV was not increased compared with controls. This suggests that the increased arterial stiffness may not be permanent in these pediatric patients with kidney disease.

Postnatal outcome in patients with fetal tachycardia

The diagnosis and management of prenatal tachyarrhythmias is well established; however, the postnatal course and outcomes are not. The purpose of our study was to review the natural history of patients with fetal tachycardia, determine the incidence of postnatal arrhythmias, and determine whether there are factors to predict which fetuses will develop postnatal arrhythmias. A retrospective chart review of patients with fetal tachyarrhythmias investigated at British Columbia Children's and Women's Hospitals between 1983 and 2010 was conducted. Sixty-nine mother-fetus pairs were eligible for the study. Fifty-two had fetal supraventricular tachycardia, and 17 had fetal atrial flutter. Conversion to sinus rhythm occurred prenatally in 52 % of patients. Postnatal arrhythmia occurred in two thirds of patients, with 82 % of those cases occurring within the first 48 h of life. Hydrops fetalis, female sex, and lack of conversion to sinus rhythm was predictive of postnatal arrhythmia (P = 0.01, P = 0.01, and P = 0.001, respectively). Conversion to sinus rhythm prenatally did not predict postnatal arrhythmia. Median duration of treatment was 9 months. Two postnatal deaths of unknown etiology occurred. Two thirds of all patients with prenatal tachycardia will develop postnatal arrhythmia. Prenatal factors that predict postnatal arrhythmia include hydrops, sex, and whether or not conversion to sinus rhythm occurred prenatally. The majority of patients with postnatal arrhythmia present within 48 h of life, which has clinical implications for monitoring. Postnatal outcome is generally very good with most patients being weaned off medication in 6-12 months.

Assessing the knowledge of sudden unexpected death in the young among Canadian medical students and recent graduates: a cross-sectional study

OBJECTIVE

To determine the level of knowledge concerning Sudden Unexpected Death in the Young (SUDY) among Canadian medical students and recent graduates (≤5 years after graduating).

DESIGN

A cross-sectional study was conducted by distributing a standardised, multiple choice, online questionnaire which assessed basic knowledge of SUDY.

SETTING

Canadian medical schools and residency training programmes.

PARTICIPANTS

614 Canadian medical students (in either their penultimate or final year) and recent graduates (≤5 years after graduating) completed an anonymous online questionnaire.

PRIMARY AND SECONDARY OUTCOME MEASURES

The level of knowledge regarding molecular aetiology, clinical presentation, pharmacological management and modes of inheritance of six of the commonest conditions causing SUDY, including hypertrophic cardiomyopathy (HCM), arrhythmogenic right ventricular cardiomyopathy (ARVC), Brugada syndrome, catecholaminergic polymorphic ventricular tachycardia (CPVT), long QT syndrome (LQT) and Wolff-Parkinson White syndrome (WPW), were compared between medical students and recent graduates. Questions were broken down into basic knowledge and advanced categories and analysed as a secondary outcome measure.

RESULTS

Of 614 responses, approximately two-thirds were answered by recent graduates, who generally scored 10% higher on all subject categories than medical students. Overall, questions regarding HCM were best answered (40%), followed by WPW syndrome (32%), CPVT (30%), ARVC (23%), Brugada syndrome (21%) and LQT syndrome (17%). Questions categorised as basic knowledge were answered 30% and 39% correctly in medical student and recent graduate groups, respectively, and those in the advanced category were answered 20% and 25% correctly.

CONCLUSIONS

Survey respondents fared poorly when answering questions regarding SUDY, which may be a reflection of inadequate medical education regarding these disorders. Standardised teaching regarding SUDY needs to occupy a stronger focus in Canadian medical curricula in order to prevent more unnecessary deaths by these syndromes in the future.

Population-based review of tetralogy of Fallot with absent pulmonary valve: is prenatal diagnosis really associated with a poor prognosis?

OBJECTIVES

Tetralogy of Fallot with absent pulmonary valve syndrome (TETAPV) is reported in obstetric literature to have an extremely poor prognosis. We sought to determine the clinical outcome associated with TETAPV and whether prenatal diagnosis confers a poor prognosis.

METHODS

All cases of TETAPV diagnosed in British Columbia between 1980 and 2009 were reviewed and grouped according to time of diagnosis, either prenatal or postnatal. The groups were compared with respect to mortality, respiratory problems, number of interventions and functional capacity at last follow-up.

RESULTS

Eight and 11 patients were included in the prenatally and postnatally diagnosed groups, with overall long-term survival of 71% and 82%, respectively. There was no significant difference in mortality, frequency of preoperative intubation, number of interventions or functional capacity between groups.

CONCLUSION

From a population-based retrospective analysis of TETAPV cases identified over three decades it is concluded that the prognosis for TETAPV is better than that previously reported in the obstetric literature. This information should be used to guide prenatal counseling.

The Study of Antiarrhythmic Medications in Infancy (SAMIS)

Background—

Supraventricular tachycardia (SVT) is one of the most common conditions requiring emergent cardiac care in children, yet its management has never been subjected to a randomized controlled clinical trial. The purpose of this study was to compare the efficacy and safety of the 2 most commonly used medications for antiarrhythmic prophylaxis of SVT in infants: digoxin and propranolol.

Methods and Results—

This was a randomized, double-blind, multicenter study of infants <4 months with SVT (atrioventricular reciprocating tachycardia or atrioventricular nodal reentrant tachycardia), excluding Wolff-Parkinson-White, comparing digoxin with propranolol. The primary end point was recurrence of SVT requiring medical intervention. Time to recurrence and adverse events were secondary outcomes. Sixty-one patients completed the study, 27 randomized to digoxin and 34 to propranolol. SVT recurred in 19% of patients on digoxin and 31% of patients on propranolol ( P =0.25). No first recurrence occurred after 110 days of treatment. The 6-month recurrence-free status was 79% for patients on digoxin and 67% for patients on propranolol ( P =0.34), and there were no first recurrences in either group between 6 and 12 months. There were no deaths and no serious adverse events related to study medication.

Conclusions—

There was no difference in SVT recurrence in infants treated with digoxin versus propranolol. The current standard practice may be treating infants longer than required and indicates the need for a placebo-controlled trial.

Clinical Trial Registration Information—

http://clinicaltrials.gov ; NCT-00390546.

Biophysical properties of the aorta and left ventricle and exercise capacity in obese children

We sought to determine whether childhood obesity is associated with increased aortic stiffness by measuring the biophysical properties of the aorta in obese children using a noninvasive echocardiographic Doppler method. Increased aortic stiffness is a strong predictor of future cardiovascular events and mortality in adults. Obesity is known to be associated with increased aortic stiffness and arterial disease in adults. We prospectively evaluated a cohort of obese children (n = 61) and compared them to normal-weight controls (n = 55). The anthropometric data were recorded. The pulsewave velocity (PWV), aortic input impedance (Zi), characteristic impedance (Zc), arterial pressure-strain elastic modulus (Ep), arterial wall stiffness index (B index), and peak aortic velocity were calculated. We correlated our echocardiographic Doppler findings with the lipid levels. We assessed the left ventricular (LV) dimensions and standard measures of cardiac function. Cardiopulmonary exercise testing was performed on all obese children. Compared to normal-weight children, obese children had a greater PWV, Zc, B index, Ep, and peak aortic velocity. Obese children had greater systolic blood pressure than normal-weight children but no difference in diastolic blood pressure. The LV dimensions and standard measures of cardiac systolic function were similar in the 2 groups, but the obese children had altered diastolic properties. The LV mass was greater in the obese children. No association was found between the lipid levels and the biophysical properties of the aorta. The relative oxygen consumption was 68% predicted in obese children. In conclusion, measures of the biophysical properties of the aorta are already abnormal in obese children, reflecting increased aortic stiffness at this early stage of disease. Obese children also had an increased LV mass, altered diastolic properties, and an abnormal exercise capacity. PWV might be useful in monitoring the progression of arterial disease or the effect of therapeutic interventions.

Economic evaluation of palivizumab in children with congenital heart disease: a Canadian perspective

BACKGROUND

Respiratory syncytial virus (RSV) is a common cause of bronchiolitis in infants. In children with congenital heart disease (CHD), it is associated with significant morbidity and mortality. Palivizumab is a monoclonal antibody that reduces the number of RSV-associated hospitalizations in children with CHD. We sought to assess cost savings and cost-effectiveness of palivizumab in children < 2 years old with hemodynamically significant CHD in a provincially administered RSV prophylaxis program.

METHODS

A cohort of children who received palivizumab (N = 292) from 2003-2007 was compared to a historical cohort of children (N = 412) from 1998-2003 who met the eligibility criteria for palivizumab prior to initiation of the prophylaxis program. Direct and indirect costs and benefits were determined.

RESULTS

The direct and indirect costs in the historical cohort were $838 per patient season compared to $9130 per patient season in the palivizumab cohort. Risk of admission was reduced by 42%, and days in hospital were reduced by 83%. The incremental cost of the RSV prophylaxis program was $8292 per patient for 1 RSV season. The incremental cost to prevent 1 day of hospitalization was $15,514. The cost of palivizumab accounted for 87.9% of the cost of prophylaxis.

CONCLUSIONS

Palivizumab is clinically effective; however, the cost was exceptionally high relative to the outcomes in this population. Given the financial constraints in a public health care setting, more strict criteria for patient selection or reduced drug costs would improve the cost-effectiveness of RSV prophylaxis.