Incremental Detection of Severe Congenital Heart Disease by Fetal Echocardiography Following a Normal Second Trimester Ultrasound Scan in Québec, Canada.

BACKGROUND: The benefit of fetal echocardiograms (FE) to detect severe congenital heart diseases (SCHD) in the setting of a normal second-trimester ultrasound is unclear. We aimed to assess whether the increase in SCHD detection rates when FE are performed for risk factors in the setting of a normal ultrasound was clinically significant to justify the resources needed. METHODS: This is a multicenter, population-based, retrospective cohort study, including all singleton pregnancies and offspring in Quebec (Canada) between 2007 and 2015. Administrative health care data were linked with FE clinical data to gather information on prenatal diagnosis of CHD, indications for FE, outcomes of pregnancy and offspring, postnatal diagnosis of CHD, cardiac interventions, and causes of death. The difference between the sensitivity to detect SCHD with and without FE for risk factors was calculated using generalized estimating equations with a noninferiority margin of 5 percentage points. RESULTS: A total of 688 247 singleton pregnancies were included, of which 30 263 had at least one FE. There were 1564 SCHD, including 1071 that were detected prenatally (68.5%). There were 12 210 FE performed for risk factors in the setting of a normal second-trimester ultrasound, which led to the detection of 49 additional cases of SCHD over 8 years. FE referrals for risk factors increased sensitivity by 3.1 percentage points (95% CI, 2.3-4.0; P<0.0001 for noninferiority). CONCLUSIONS: In the setting of a normal second-trimester ultrasound, adding a FE for risk factors offered low incremental value to the detection rate of SCHD in singleton pregnancies. The current ratio of clinical gains versus the FE resources needed to screen for SCHD in singleton pregnancies with isolated risk factors does not seem favorable. Further studies should evaluate whether these resources could be better allocated to increase SCHD sensitivity at the ultrasound level, and to help decrease heterogeneity between regions, institutions and operators.

The Mathematical Limitations of Fetal Echocardiography as a Screening Tool in the Setting of a Normal Second-Trimester Ultrasound.

BACKGROUND: The effectiveness of screening strategies targeting pregnancies at higher risk of congenital heart disease (CHD) is reduced by the low prevalence of severe CHD, the increase in CHD detection rates by second-trimester ultrasound (U/S), and the high proportion of severe CHD in low-risk pregnancies. We aimed to determine situations in which additional screening by fetal echocardiography (FE) would result in a significant increase in sensitivity and a sizable decrease in the false-negative rate of detection of severe CHD. METHODS: We simulated the change in the numbers of detected severe CHD cases when FE is offered to women with a normal second-trimester U/S who have a higher risk of bearing a child with CHD, compared to U/S alone. The primary outcome was the increase in sensitivity. Secondary outcomes were the number needed to screen and the reduction in the rate of missed cases. RESULTS: For an U/S sensitivity of 60%, the addition of FE in pregnancies at high risk of CHD (risk ratio 3.5; range: 2 to 5) increased sensitivity by 2.4 percentage points (1.1 to 7.9). The number needed to screen to detect one additional case of severe CHD was 436 (156 to 952). The rate of additional severe CHD cases detected by FE was 4 per 100,000 pregnancies (2 to 32). CONCLUSIONS: The addition of FE to U/S for severe CHD prenatal screening in pregnancies at high risk of CHD yielded marginal benefits in terms of increased sensitivity and decreased rates of false negatives, at the expense of significant resource utilization.

CONTEXTE: L'efficacité des stratégies de dépistage ciblant les grossesses à haut risque de cardiopathie congénitale (CC) se trouve réduite par la faible prévalence des CC sévères, par l'augmentation des taux de détection des CC par l'échographie (E/G) du deuxième trimestre, et par la proportion élevée de CC sévères dans les grossesses à faible risque. Dans le cadre de la détection prénatale des CC sévères, nous avons cherché à identifier les situations pour lesquelles un dépistage supplémentaire par échocardiographie fœtale (EF) entraînerait une augmentation significative de la sensibilité et une diminution notable du taux de faux négatifs. MÉTHODES: Nous avons simulé le changement du nombre de cas de CC sévère détectées lorsque l'EF est proposée aux femmes dont l'E/G du deuxième trimestre est normal et qui présentent un risque plus élevé de porter un enfant atteint de CC, par rapport à l'examen du deuxième trimestre seul. L'issue primaire était l'augmentation de la sensibilité. Les issues secondaires étaient le nombre de dépistages nécessaires et la réduction du taux de cas manqués. RÉSULTATS: Pour une sensibilité de l'E/G de 60 %, l'ajout de l'EF pour les grossesses à haut risque de CC (rapport de risque de 3,5; intervalle: 2 à 5) a accru la sensibilité de 2,4 points de pourcentage (1,1 à 7,9). Le nombre de dépistages nécessaires pour détecter un cas supplémentaire de CC sévères était de 436 (156 à 952). La proportion de cas supplémentaires de CC sévères détectées par EF était de 4 pour 100 000 grossesses (2 à 32). CONCLUSIONS: L'ajout de l'EF à l'E/G pour le dépistage prénatal des CC sévères pour les grossesses à risque élevé de CC n'a apporté que des avantages marginaux en termes d'augmentation de la sensibilité et de diminution des taux de faux négatifs, cela au prix d'une utilisation importante des ressources.

Novel Z Scores to Correct Biases Due to Ventricular Volume Indexing to Body Surface Area in Adolescents and Young Adults.

BACKGROUND: Reference values for cardiac magnetic resonance imaging (cMRI) in children and young adults are scarce. This leads to risk stratification of patients with congenital heart diseases being based on volumes indexed to body surface area (BSA). We aimed to produce cMRI Z score equations for ventricular volumes in children and young adults and to test whether indexing to BSA resulted in an incorrect assessment of ventricular dilation according to sex, body composition, and growth. METHODS: We retrospectively included 372 subjects aged < 26 years with either normal hearts or conditions with no impact on ventricular volumes (reference group), and 205 subjects with repaired tetralogy of Fallot (TOF) aged < 26 years. We generated Z score equations by means of multivariable regression modelling. Right ventricular dilation was assessed with the use of Z scores and compared with indexing to BSA in TOF subjects. RESULTS: Ventricular volume Z scores were independent from age, sex, and anthropometric measurements, although volumes indexed to BSA showed significant residual association with sex and body size. In TOF subjects, indexing overestimated dilation in growing children and underestimated dilation in female compared with male subjects, and in overweight compared with lean subjects. CONCLUSIONS: Indexed ventricular volumes measured with cMRI did not completely adjust for body size and resulted in a differential error in the assessment of ventricular dilation according to sex and body size. Our proposed Z score equations solved this problem. Future studies should evaluate if ventricular volumes expressed as Z scores have a better prognostic value than volumes indexed to BSA.

New Comprehensive Reference Values for Arterial Vascular Parameters in Children.

BACKGROUND: Noninvasive measurements of vascular parameters can be used for the detection and risk stratification of cardiovascular diseases. Most vascular parameters are influenced by age and body size, but pediatric reference values are scarce and limited to a few parameters. The aim of this study was to develop pediatric reference values and Z score equations for a comprehensive set of vascular parameters. METHODS: A total of 292 healthy subjects aged 0 to 18 years were prospectively recruited. Stiffness index ß, pressure-strain elastic modulus, common carotid intima-media thickness, brachial flow-mediated dilation, radial augmentation index, central and right arm peripheral artery pulse-wave velocities, and pulse-wave velocity ratio were assessed. Normalization for age and anthropometric variables was performed using parametric multivariate regression modeling. Z scores were assessed for heteroscedasticity, residual association with age and body size, and distribution. RESULTS: Multivariate regression models with various combinations of height, weight, and age were used to obtain Z scores that were independent of age and body size. There was no residual association between Z scores and body size, age, or body mass index. There was no significant departure from the normal distribution. CONCLUSIONS: The authors present reference values and Z score equations for a comprehensive set of vascular parameters during childhood. Further studies are necessary to assess their usefulness in detecting the vascular signs of subclinical atherosclerosis and chronic diseases, including congenital heart disease.

Rationale and Design of the FREQUENCY Study: The Fetal Cardiac Registry of Québec to Improve Resource Utilization in Fetal Cardiology.

OBJECTIVE: Prenatal detection of congenital heart diseases (CHD) decreases morbidity and cost. To improve detections rates, most physicians refer pregnant women with high-risk pregnancies to fetal cardiologists even when there is no suspicion of CHD at the second trimester screening. This paper presents the rationale and detailed method of the Fetal Cardiac Registry of Québec to Improve Resource Utilization in Fetal Cardiology (FREQUENCY) study. The overall objective is to assess the impact of second trimester ultrasound screening (U/S) and referral pattern in fetal cardiology on detection rates, health care costs, and resource utilization, as well as perinatal morbidity and mortality. METHODS: This multicentre retrospective population-based cohort study will link fetal echocardiography data from all centres performing fetal echocardiography in Québec with administrative health care data. This data linking will allow the determination of a true denominator (all women in Québec who underwent second trimester U/S) with complete follow-up of up to 2 years for offspring. This protocol meets Canadian Task Force Classification II-2. RESULTS: The study investigators have collected and cleaned fetal echocardiography data for 24 259 eligible pregnancies referred to fetal cardiology. These data will be matched to approximately 860 000 pregnancies between 2007 and 2015. CONCLUSION: The results of the FREQUENCY study will shed light on the impact of the current prenatal CHD screening strategy in Canada.

A multicentre investigation of organ and tissue donation education for critical care residents.

PURPOSE: To describe critical care medicine residents' training, expertise, and skills regarding organ and tissue donation processes and procedures. METHODS: We undertook a qualitative multicentre study and employed a purposive sample of program directors, physicians, nurses, residents, and organ donation leaders from all nine academic intensive care unit (ICU) training centres (five adult, four pediatric) in Ontario (n = 71). Interviews, conducted by telephone between December 2015 and March 2016, were audio-recorded and transcribed verbatim. Data collection and analysis were performed using an iterative process and continued until saturation was achieved. RESULTS: Five main themes were identified: 1) gaps in residents' knowledge for both neurologic determination of death (NDD) and circulatory determination of death (DCD) cases; 2) commitment to the provision of organ and tissue donation training; 3) limited experiential learning (NDD and DCD); 4) challenges related to the provision of training on organ donation and need for a standardized curriculum; and 5) communication with family members. Overall, this study showed system-level gaps in training resulting from the lack of a standardized provincial curriculum on organ donation. CONCLUSIONS: Qualitative data corroborated that residents need more exposure to clinical cases, especially regarding DCD donors. A standardized education curriculum would be beneficial for all residents within the ICU. Developing a better shared understanding of the donation process will improve team communication and performance, translate into a better end-of-life experience for families, and potentially result in increased donation rates.