Proposed competencies for the performance of cardiovascular computed tomography in pediatric and adult congenital heart disease.

Cardiovascular computed tomography (CCT) is rated appropriate by published guidelines for the initial evaluation and follow up of congenital heart disease (CHD) and is an essential modality in cardiac imaging programs for patients of all ages. However, no recommended core competencies exist to guide CCT in CHD imaging training pathways, curricula development, or establishment of a more formal educational platform. To fill this gap, a group of experienced congenital cardiac imagers, intentionally inclusive of adult and pediatric cardiologists and radiologists, was formed to propose core competencies fundamental to the expert-level performance of CCT in pediatric acquired and congenital heart disease and adult CHD. The 2020 SCCT Guideline for Training Cardiology and Radiology Trainees as Independent Practitioners (Level II) and Advanced Practitioners (Level III) in Cardiovascular Computed Tomography (1) for adult imaging were used as a framework to define pediatric and CHD-specific competencies. Established competencies will be immediately relevant for advanced cardiac imaging fellowships in both cardiology and radiology training pathways. Proposed future steps include radiology and cardiology society collaboration to establish provider certification levels, training case-volume recommendations, and continuing medical education (CME) requirements for expert-level performance of CCT in pediatric and adult CHD.

Cardiac Magnetic Resonance Imaging to Determine Single Ventricle Function in a Pediatric Population is Feasible in a Large Trial Setting: Experience from the Single Ventricle Reconstruction Trial Longitudinal Follow up.

The Single Ventricle Reconstruction (SVR) Trial was a randomized prospective trial designed to determine survival advantage of the modified Blalock-Taussig-Thomas shunt (BTTS) vs the right ventricle to pulmonary artery conduit (RVPAS) for patients with hypoplastic left heart syndrome. The primary aim of the long-term follow-up (SVRIII) was to determine the impact of shunt type on RV function. In this work, we describe the use of CMR in a large cohort follow up from the SVR Trial as a focused study of single ventricle function. The SVRIII protocol included short axis steady-state free precession imaging to assess single ventricle systolic function and flow quantification. There were 313 eligible SVRIII participants and 237 enrolled, ages ranging from 10 to 12.5 years. 177/237 (75%) participants underwent CMR. The most common reasons for not undergoing CMR exam were requirement for anesthesia (n = 14) or ICD/pacemaker (n = 11). A total of 168/177 (94%) CMR studies were diagnostic for RVEF. Median exam time was 54 [IQR 40-74] minutes, cine function exam time 20 [IQR 14-27] minutes, and flow quantification time 18 [IQR 12-25] minutes. There were 69/177 (39%) studies noted to have intra-thoracic artifacts, most common being susceptibility artifact from intra-thoracic metal. Not all artifacts resulted in non-diagnostic exams. These data describe the use and limitations of CMR for the assessment of cardiac function in a prospective trial setting in a grade-school-aged pediatric population with congenital heart disease. Many of the limitations are expected to decrease with the continued advancement of CMR technology.

Patent Ductus Arteriosus Response to Treatment by Course and Associations with Perinatal and Clinical Factors.

OBJECTIVE: The objective of this study is to examine patent ductus arteriosus (PDA) response by treatment course and investigate associations with postmenstrual age (PMA), chronological age (CA), gestational age (GA), antenatal steroid exposure (ANS), birthweight (BW), weight at treatment initiation (WT), and PDA/left pulmonary artery (LPA) ratio. STUDY DESIGN: This is a single-center retrospective cohort study of preterm infants less than 37 weeks' GA born January 1, 2016 to December 31, 2018 who received acetaminophen and/or indomethacin for PDA treatment. Cox proportional hazards regression models were used to determine whether factors of interest were associated with PDA response to medical treatment. RESULTS: In total, 289 treatment courses were administered to 132 infants. Thirty-one (23%) infants experienced treatment-associated PDA closure. Ninety-four (71%) infants had evidence of PDA constriction following any treatment course. Ultimately, 84 (64%) infants experienced definitive PDA closure. For each 7-day increase in CA at the time of treatment initiation, the PDA was 59% less likely to close (p = 0.04) and 42% less likely to respond (i.e., constrict or close) to treatment (p < 0.01). PDA/LPA ratio was associated with treatment-associated PDA closure (p = 0.01). For every 0.1 increase in the PDA/LPA ratio, the PDA was 19% less likely to close in response to treatment. CONCLUSION: In this cohort, PDA closure is independent of PMA, GA, ANS, BW, and WT; however, CA at treatment initiation predicted both treatment-associated PDA closure and PDA response (i.e., constriction or closure), and PDA/LPA ratio was associated with treatment-associated closure. Most infants experienced PDA constriction rather than closure, despite receiving up to four treatment courses. KEY POINTS: · Detailed PDA responses for up to four treatment courses provide a novel perspective.. · Chronological age at the start of treatment predicted treatment-associated PDA closure and response.. · For each 7-day increase in chronological age, the PDA was 59% less likely to close..

Preoperative Computed Tomographic Angiography Can Predict Need for Branch Pulmonary Artery Intervention in Patients With Ductal-Dependent Pulmonary Blood Flow.

BACKGROUND: Neonates with ductal-dependent pulmonary blood flow (DD-PBF) are at risk for pulmonary artery (PA) stenosis. The objective of this study was to identify preoperative cardiovascular computed tomography angiography (CTA) measures that are associated with the need for branch PA intervention. METHODS: We identified neonates with DD-PBF who underwent preoperative CTA at our center and were followed for 24 months. The primary outcome was requiring intervention for branch PA stenosis at the initial or subsequent procedure. Patients were divided into three groups: 1) No PA intervention, 2) Initial PA intervention, and 3) Remote PA intervention. Measurements of the branch PAs and patent ductus arteriosus (PDA) were made prospectively. RESULTS: Forty patients were included, 7 (18%) did not receive a PA intervention, 23 (58%) were in the initial PA intervention group, and 10 (25%) were in the remote PA intervention group. The distance from PA bifurcation to the largest diameter of the PA that receives the PDA showed a difference between the no-intervention group versus the initial and remote intervention groups (0.8 mm [IQR 0.7, 2.0], 8.2 mm [IQR 1.9, 13.7], 8.5 mm [IQR 6.5, 11.1], respectively, P = .02). The receiver operating characteristic curve showed a distance >2.2 mm had a sensitivity = 91% and specificity = 86% in predicting the need for PA intervention. CONCLUSION: The distance from the PA bifurcation to the largest diameter of the branch PA that accepts the PDA on preoperative CTA is highly predictive of the need for initial or remote PA intervention in this group. Preoperative CTA should be considered for risk stratification in neonates undergoing intervention for DD-PBF.

The Utility of CT Angiography in Neonates with Pulmonary Atresia with Intact Ventricular Septum and Concern for Right Ventricular Dependent Coronary Circulation: Case Series.

Up to one third of patients with pulmonary atresia with intact ventricular septum (PA-IVS) will have inadequate anterograde coronary blood flow and rely on fistulous connections from the right ventricle (RV) for myocardial perfusion, known as RV-dependent coronary circulation (RVDCC). Historically, identification of the extent of ventriculocoronary connections and coronary stenosis has required invasive imaging with cardiac catheterization and angiography. Cardiac computed tomography (CCT) potentially provides a less invasive imaging option for therapeutic planning in this group of patients. We describe six neonates with PA-IVS who underwent both CCT and cardiac catheterization at our institution prior to any surgical or transcatheter intervention between 2009 and 2019. Imaging was concerning for RVDCC in all six patients. The average tricuspid Z-score was - 4.19 (2.1 to - 5.34). Two patients underwent cardiac transplantation and two patients underwent ductal stenting. The overall mortality rate was 50%. CCT findings closely mirrored the findings of invasive cardiac catheterization and identified important morphological variations. The average radiation exposure (DLP) per CCT was (10.5 mGy cm, range 6-20). Technological improvements in CCT have enabled adequate visualization of coronary anomalies in children with comparable accuracy to cardiac catheterization, but considerably less radiation exposure. However, diagnosis of RVDCC requires direct right ventricular angiography. Therefore, the potential benefit of obtaining a CCT prior to catheterization for infants with PA-IVS is the ability to risk stratify, assist with procedural planning, and improve family counseling.

Successful Reduction of Postoperative Chest Tube Duration and Length of Stay After Congenital Heart Surgery: A Multicenter Collaborative Improvement Project.

Background Congenital heart disease practices and outcomes vary significantly across centers, including postoperative chest tube (CT) management, which may impact postoperative length of stay (LOS). We used collaborative learning methods to determine whether centers could adapt and safely implement best practices for CT management, resulting in reduced postoperative CT duration and LOS. Methods and Results Nine pediatric heart centers partnered together through 2 learning networks. Patients undergoing 1 of 9 benchmark congenital heart operations were included. Baseline data were collected from June 2017 to June 2018, and intervention-phase data were collected from July 2018 to December 2019. Collaborative learning methods included review of best practices from a model center, regular data feedback, and quality improvement coaching. Center teams adapted CT removal practices (eg, timing, volume criteria) from the model center to their local resources, practices, and setting. Postoperative CT duration in hours and LOS in days were analyzed using statistical process control methodology. Overall, 2309 patients were included. Patient characteristics did not differ between the study and intervention phases. Statistical process control analysis showed an aggregate 15.6% decrease in geometric mean CT duration (72.6 hours at baseline to 61.3 hours during intervention) and a 9.8% reduction in geometric mean LOS (9.2 days at baseline to 8.3 days during intervention). Adverse events did not increase when comparing the baseline and intervention phases: CT replacement (1.8% versus 2.0%, P=0.56) and readmission for pleural effusion (0.4% versus 0.5%, P=0.29). Conclusions We successfully lowered postoperative CT duration and observed an associated reduction in LOS across 9 centers using collaborative learning methodology.

High Acuity Therapy Variation Across Pediatric Acute Care Cardiology Units: Results from the Pediatric Acute Care Cardiology Collaborative Hospital Surveys.

We utilized the multicenter Pediatric Acute Care Cardiology Collaborative (PAC3) 2017 and 2019 surveys to describe practice variation in therapy availability and changes over a 2-year period. A high acuity therapies (ATs) score was derived (1 point per positive response) from 44 survey questions and scores were compared to center surgical volume. Of 31 centers that completed the 2017 survey, 26 also completed the 2019 survey. Scores ranged from 11 to 34 in 2017 and 11 to 35 in 2019. AT scores in 2019 were not statistically different from 2017 scores (29/44, IQR 27-32.5 vs. 29.5/44, IQR 27-31, p = 0.9). In 2019, more centers reported initiation of continuous positive airway pressure (CPAP) and Bi-level positive airway pressure (BiPAP) in Acute Care Cardiology Unit (ACCU) (19/26 vs. 4/26, p < 0.001) and permitting continuous CPAP/BiPAP (22/26 vs. 14/26, p = 0.034) compared to 2017. Scores in both survey years were significantly higher in the highest surgical volume group compared to the lowest, 33 ± 1.5 versus 25 ± 8.5, p = 0.046 and 32 ± 1.7 versus 23 ± 5.5, p = 0.009, respectively. Variation in therapy within the ACCUs participating in PAC3 presents an opportunity for shared learning across the collaborative. Experience with PAC3 was associated with increasing available respiratory therapies from 2017 to 2019. Whether AT scores impact the quality and outcomes of pediatric acute cardiac care will be the subject of further investigation using a comprehensive registry launched in early 2019.

Multi-institution assessment of the use and risk of cardiovascular computed tomography in pediatric patients with congenital heart disease.

BACKGROUND: Cardiac computed tomography (CT) is increasingly used in pediatric patients with congenital heart disease (CHD). Variability of practice and of comprehensive diagnostic risk across institutions is not known. METHODS: Four centers prospectively enrolled consecutive pediatric CHD patients <18 years of age undergoing cardiac CT from January 6, 2017 to 1/30/2020. Patient characteristics, cardiac CT data and comprehensive diagnostic risk were compared by age and institutions. Risk categories included sedation and anesthesia use, vascular access, contrast exposure, cardiovascular medication, adverse events (AEs), and estimated radiation dose. RESULTS: Cardiac CT was performed in 1045 pediatric patients at a median (interquartile range, IQR) age of 1.7 years (0.3, 11.0). The most common indications were arterial abnormalities, suspected coronary artery anomalies, functionally single ventricle heart disease, and tetralogy of Fallot/pulmonary atresia. Sedation was used in 8% and anesthesia in 11% of patients. Peripheral vascular access was utilized for 93%. Median contrast volume was 2 â€‹ml/kg. Beta blockers were administered in 11% of cases and nitroglycerin in 2% of cases. The median (IQR) total procedural dose length product (DLP) was 20 â€‹mGy∗cm (10, 50). Sedation, vascular access, contrast exposure, use of cardiovascular medications and radiation dose estimates varied significantly by institution and age (p â€‹< â€‹0.001). Seven minor adverse events (0.7%) and no major adverse events were reported. CONCLUSION: Cardiac CT for CHD is safe in pediatric patients when appropriate CT technology and expertise are available. Scans can be acquired at relatively low radiation exposure with few minor adverse events.

Improved outcomes after implementation of a specialized pediatric cardiac rapid response team.

INTRODUCTION: The efficacy of a specialized pediatric cardiac rapid response team is unknown. We hypothesized that a specialized cardiac rapid response team would facilitate team-wide communication between the cardiac stepdown unit and cardiac intensive care unit (ICU) teams and improve patient care. MATERIALS AND METHODS: A specialized pediatric cardiac rapid response team was implemented in June 2015. All pediatric cardiac rapid response team activations and outcomes from implementation through December 2018 were reviewed. Cardiac arrests and unplanned transfers to the cardiac ICU were indexed to 1000 patient-days to account for inpatient volume trends and evaluated over time. RESULTS: There were 202 cardiac rapid response team activations in 108 unique patients during the study period. After implementation of the pediatric cardiac rapid response team, unplanned transfers from the cardiac stepdown unit to the cardiac ICU decreased from 16.8 to 7.1 transfers per 1000 patient days (p = 0.012). The stepdown unit cardiac arrest rate decreased from 1.2 to 0.0 arrests per 1000 patient-days (p = 0.015). There was one death on the cardiac stepdown unit in the 5 years since the implementation of the cardiac rapid response team, compared to four deaths in the previous 5 years. CONCLUSIONS: A reduction in unplanned cardiac ICU transfers, cardiac arrests, and mortality on the cardiac stepdown unit has been observed since the implementation of a specialized pediatric cardiac rapid response team. A specialized cardiac rapid response team may improve communication and empower the interdisciplinary care team to escalate care for patients experiencing clinical decline.

Recommendations for risk stratified use of cardiac computed tomography for congenital heart disease during the COVID-19 pandemic.

The impact of the coronavirus disease (COVID-19) pandemic in the United States and around the world has required significant changes to medical practice. Amidst the rapidly evolving public health emergency, hospital centers have been required to postpone elective procedures, preserve personal protective equipment (PPE), practice social distancing and limit staff exposures. Patients with congenital heart disease (CHD) often need urgent evaluation, most commonly for preprocedural evaluation. We have stratified the most common indications for cardiac computed tomography (CCT) imaging in patients with CHD to help guide care for these patients during the COVID-19 pandemic including considerations for reopening.

Intensive Care Unit and Acute Care Unit Length of Stay After Congenital Heart Surgery.

BACKGROUND: Postoperative length of stay (LOS) is an important quality metric and is known to vary widely across hospitals after congenital heart surgery. Whether this variability is explained by factors associated with the intensive care unit (ICU) or acute care unit (ACU) remains unclear. We evaluated the relationship between ICU and ACU LOS and the impact of ACU characteristics on postoperative LOS. METHODS: Hospitalizations for congenital heart surgery within the Pediatric Cardiac Critical Care Consortium (PC4) registry (August 2014 to February 2018) were included. Models were developed for ICU, ACU, and postoperative LOS by adjusting for differences in case-mix across hospitals. PC4 hospitals participating in the Pediatric Acute Care Cardiology Collaborative (PAC3) were also surveyed on ACU organizational factors and practice patterns. RESULTS: Overall, 19,674 hospitalizations across 27 hospitals were included. There was significant variation in ICU and ACU LOS. Postperative LOS appeared to be most closely related to ICU LOS; 75% (6 of 8) of hospitals with shorter than expected postoperative LOS also had shorter than expected ICU LOS. A clear relationship between postoperative and ACU LOS was not observed. Hospitals with an ACU able to provide higher-acuity care as indexed according to the PAC3 survey were more likely to have shorter postoperative LOS (P < .01). CONCLUSIONS: For hospitals that achieve shorter than expected postoperative LOS after congenital heart surgery, ICU LOS appears to be the primary driver. Higher-acuity resources in the ACU may be an important factor facilitating earlier transfer from the ICU. These data are key to informing quality improvement initiatives geared toward reducing postoperative LOS.

Center Variation in Chest Tube Duration and Length of Stay After Congenital Heart Surgery.

BACKGROUND: Nearly every child undergoing congenital heart surgery has chest tubes placed intraoperatively. Center variation in removal practices and impact on outcomes has not been well described. This study evaluated variation in chest tube management practices and outcomes across centers. METHODS: The study included patients undergoing any of 10 benchmark operations from June 2017 to May 2018 at participating Pediatric Acute Care Cardiology Collaborative (PAC3) and Pediatric Cardiac Critical Care Consortium (PC4) centers. Clinical data from PC4 centers were merged with chest tube data from PAC3 centers. Practices and outcomes were compared across centers in univariate and multivariable analysis. RESULTS: The cohort included 1029 patients (N = 9 centers). Median chest tube duration varied significantly across centers for 9 of 10 benchmark operations (all P ≤ .03), with a "model" center noted to have the shortest duration for 9 of 10 operations (range, 27.9% to 87.4% shorter duration vs other centers across operations). This effect persisted in multivariable analysis (P < .0001). The model center had higher volumes of chest tube output before removal (median, 8.5 mL/kg/24 h [model] vs 2.2 mL/kg/24 h [other centers]; P < .001], but it did not have higher rates of chest tube reinsertion (model center 1.3% vs 2.1%; P = .59) or readmission for pleural effusion (model center 4.4% vs 3.0%; P = .31), and had the shortest length of stay for 7 of 10 operations. CONCLUSIONS: This study suggests significant center variation in chest tube removal practices and associated outcomes after congenital heart surgery. Best practices used at the model center have informed the design of an ongoing collaborative learning project aimed at reducing chest tube duration and length of stay.

Diagnostic Accuracy of Noncontrast Self-navigated Free-breathing MR Angiography versus CT Angiography: A Prospective Study in Pediatric Patients with Suspected Anomalous Coronary Arteries.

RATIONALE AND OBJECTIVES: To evaluate the diagnostic accuracy of a prototype noncontrast, free-breathing, self-navigated 3D (SN3D) MR angiography (MRA) technique for the assessment of coronary artery anatomy in children with known or suspected coronary anomalies, using CT angiography (CTA) as the reference standard. MATERIALS AND METHODS: Twenty-one children (15 male, 12.3 ± 2.6 years) were prospectively enrolled between July 2014 and August 2016 in this IRB-approved, HIPAA-compliant study. Patients underwent same-day unenhanced SN3D-MRA and contrast-enhanced CTA. Two observers rated the visualization of coronary artery segments and diagnostic confidence on a 3-point scale and assessed coronary arteries for anomalous origin, as well as interarterial and intramural course. Sensitivity, specificity, positive (PPV) and negative predictive values (NPV) of SN3D-MRA for the detection of coronary artery abnormalities were calculated. Interobserver agreement was assessed using Intraclass Correlation Coefficients (ICC). RESULTS: Fourteen children showed coronary artery abnormalities on CTA. The visualization of coronary segments was rated significantly higher for CTA compared to MRA (p <0.015), except for the left main coronary artery (p = 0.301), with good to excellent interobserver agreement (ICC = 0.62-0.94). Diagnostic confidence was higher for CTA (p = 0.046). Sensitivity, specificity, PPV, and NPV of MRA were 92%, 92%, 96%, and 87% for the detection of coronary artery anomalies, 85%, 85%, 74%, and 92% for high origin, 71%, 92%, 82%, and 87% for interarterial, and 41%, 96%, 87%, and 80% for intramural course. CONCLUSIONS: Noncontrast SN3D-MRA is highly accurate for the detection of coronary artery anomalies in pediatric patients while diagnostic confidence and coronary artery visualization remain superior with CTA.

Variation in care practices across pediatric acute care cardiology units: Results of the Pediatric Acute Care Cardiology Collaborative (PAC3 ) hospital survey.

BACKGROUND: The Pediatric Acute Care Cardiology Collaborative (PAC3 ) was established in 2014 to improve the quality, value, and experience of hospital-based cardiac acute care outside of the intensive care unit. An initial PAC3 project was a comprehensive survey to understand unit structure, practices, and resource utilization across the collaborative. This report aims to describe the previously unknown degree of practice variation across member institutions. METHODS: A 126-stem question survey was developed with a total of 412 possible response fields across nine domains including demographics, staffing, available resources and therapies, and standard care practices. Five supplemental questions addressed surgical case volume and number of cardiac acute care unit (CACU) admissions. Responses were recorded and stored in Research Electronic Data Capture (REDCap). RESULTS: Surveys were completed by 31 out of 34 centers (91%) with minimal incomplete fields. A majority (61%) of centers have a single dedicated CACU, which is contiguous or adjacent to the intensive care unit in 48%. A nurse staffing ratio of 3:1 is most common (71%) and most (84%) centers employed a resource nurse. Centralized wireless rhythm monitoring is used in 84% of centers with 54% staffed continuously. There was significant variation in the use of noninvasive respiratory support, vasoactive infusions, and ventricular assist devices across the collaborative. Approximately half of the surveyed centers had lesion-specific postoperative pathways and approximately two-thirds had protocols for single-ventricle patients. CONCLUSIONS: The PAC3 hospital survey is the most comprehensive description of systems and care practices unique to CACUs to date. There exists considerable heterogeneity among unit composition and variation in care practices. These variations may allow for identification of best practices and improved quality of care for patients.

Development of a congenital cardiovascular computed tomography imaging registry: Rationale and implementation.

BACKGROUND: The cumulative exposure and risk of anesthesia, vascular access, contrast agents and radiation is emerging as a significant lifelong burden in patients with congenital heart disease (CHD). Latest generation computerized tomographic (CT) scanners are increasingly used for high resolution cardiovascular imaging and have both hardware and post processing radiation dose reduction strategies that can be implemented. Currently, these dose reduction strategies are not uniformly applied and there is a large variability in radiation dose used for the performance of CT in CHD. METHODS: We propose the development and implementation of a prospective, multi-center and multi-specialty consortium to measure the variability of use, risk and image quality of CT scans in patients of all ages with CHD. The primary goals of this collaboration are 1) define variability of use, diagnostic quality, and risk of cardiac CT 2) establish best practice guidelines designed to optimize diagnostic image quality with appropriate use of radiation and anesthesia exposure 3) provide institution specific feedback compared with the group norm across participating centers 4) improve the level of evidence for the use of CT in CHD through the collection of prospective and multi-institutional data. CONCLUSIONS: Prospective multi-institutional data is needed to inform risk estimates of CT in CHD using current generation scanners and aggressive dose optimization techniques. This registry will provide a platform for future collaboration establishing a multi-modality risk assessment tool specific to patients with CHD.

Coronary artery assessment using self-navigated free-breathing radial whole-heart magnetic resonance angiography in patients with congenital heart disease.

OBJECTIVES: To evaluate a self-navigated free-breathing three-dimensional (SNFB3D) radial whole-heart MRA technique for assessment of main coronary arteries (CAs) and side branches in patients with congenital heart disease (CHD). METHODS: SNFB3D-MRA datasets of 109 patients (20.1±11.8 years) were included. Three readers assessed the depiction of CA segments, diagnostic confidence in determining CA dominance, overall image quality and the ability to freeze cardiac and respiratory motion. Vessel sharpness was quantitatively measured. RESULTS: The percentages of cases with excellent CA depiction were as follows (mean score): left main, 92.6 % (1.92); left anterior descending (LAD), 88.3 % (1.88); right (RCA), 87.8 % (1.85); left circumflex, 82.8 % (1.82); posterior descending, 50.2 % (1.50) and first diagonal, 39.8 % (1.39). High diagnostic confidence for the assessment of CA dominance was achieved in 56.2 % of MRA examinations (mean score, 1.56). Cardiac motion freezing (mean score, 2.18; Pearson's r=0.73, P<0.029) affected image quality more than respiratory motion freezing (mean score, 2.20; r=0.58, P<0.029). Mean quantitative vessel sharpness of the internal thoracic artery, RCA and LAD were 53.1, 52.5 and 48.7 %, respectively. CONCLUSIONS: Most SNFB3D-MRA examinations allow for excellent depiction of the main CAs in young CHD patients; visualisation of side branches remains limited. KEY POINTS: • Self-navigated free-breathing three-dimensional magnetic resonance angiography (SNFB3D-MRA) sufficiently visualises coronary arteries (CAs). • Depiction of main CAs in patients with congenital heart disease is excellent. • Visualisation of CA side branches using SNFB3D-MRA is limited. • SNFB3D-MRA image quality is especially correlated to cardiac motion freezing ability.

Longitudinal measures of deformation are associated with a composite measure of contractility derived from pressure-volume loop analysis in children.

Aims: The relationship between echocardiographic measures of left ventricular (LV) systolic function and reference-standard measures have not been assessed in children. The objective of this study was to assess the validity of echocardiographic indices of LV systolic function via direct comparison to a novel composite measure of contractility derived from pressure-volume loop (PVL) analysis. Methods and results: Children with normal loading conditions undergoing routine left heart catheterization were prospectively enrolled. PVLs were obtained via conductance catheters. A composite invasive composite contractility index (ICCI) was developed using data reduction strategies to combine four measures of contractility derived from PVL analysis. Echocardiograms were performed immediately after PVL analysis under the same anesthetic conditions. Conventional and speckle-tracking echocardiographic measures of systolic function were measured. Of 24 patients, 18 patients were heart transplant recipients, 6 patients had a small patent ductus arteriosus or small coronary fistula. Mean age was 9.1 ± 5.6 years. Upon multivariable regression, longitudinal strain was associated with ICCI (ß = -0.54, P = 0.02) while controlling for indices of preload, afterload, heart rate, and LV mass under baseline conditions. Ejection fraction and shortening fraction were associated with LV mass and load indices, but not contractility. Conclusion: Speckle-tracking derived longitudinal strain is associated ICCI in children with normal loading conditions. Longitudinal measures of deformation appear to accurately assess LV contractility in children.

An interactive simulation tool for patient-specific clinical decision support in single-ventricle physiology.

OBJECTIVE: Modeling of single-ventricle circulations has yielded important insights into their unique flow dynamics and physiology. Here we translated a state-of-the-art mathematical model into a patient-specific clinical decision support interactive Web-based simulation tool and show validation for all 3 stages of single-ventricular palliation. METHODS: Via the adoption a validated lumped parameter method, complete cardiovascular-pulmonary circulatory models of all 3 stages of single-ventricle physiology were created within a simulation tool. The closed-loop univentricular heart model includes scaling for growth and respiratory effects, and typical patient-specific parameters are entered through an intuitive user interface. The effects of medical or surgical interventions can be simulated and compared. To validate the simulator, patient parameters were collected from catheterization reports. Four simulator outputs were compared against catheterization findings: pulmonary to systemic flow ratio (Qp:Qs), systemic arterial saturation (SaO2), mean pulmonary arterial pressure (mPAp), and systemic-venous oxygen difference (SaO2-SvO2). RESULTS: Data from 60 reports were used. Compared with the clinical values, the simulator results were not significantly different in mean Qp:Qs, SaO2, or mPAp (P > .09). There was a statistical but clinically insignificant difference in average SaO-SvO2 (average difference 1%, P < .01). Linear regression analyses revealed a good prediction for each variable (Qp:Qs, R2 = 0.79; SaO2, R2 = 0.64; mPAp, R2 = 0.69; SaO2-SvO2, R2 = 0.93). CONCLUSIONS: This simulator responds quickly and predicts patient-specific hemodynamics with good clinical accuracy. By predicting postoperative and postintervention hemodynamics in all 3 stages of single-ventricle physiology, the simulator could assist in clinical decision-making, training, and consultation. Continuing model refinement and validation will further its application to the bedside.

Echocardiographic Detection of Increased Ventricular Diastolic Stiffness in Pediatric Heart Transplant Recipients: A Pilot Study.

BACKGROUND: Pediatric heart transplant recipients are at risk for increased left ventricular (LV) diastolic stiffness. However, the noninvasive evaluation of LV stiffness has remained elusive in this population. The objective of this study was to compare novel echocardiographic measures of LV diastolic stiffness versus gold-standard measures derived from pressure-volume loop (PVL) analysis in pediatric heart transplant recipients. METHODS: Patients undergoing left heart catheterization were prospectively enrolled. PVLs were obtained via conductance. The end-diastolic pressure-volume relationship was obtained via balloon occlusion. The stiffness constant, ß, was calculated. Echocardiographic measures of diastolic function were derived from spectral and tissue Doppler and two-dimensional speckle-tracking. Ventricular volumes were measured using three-dimensional echocardiography. The novel echocardiographic estimates of ventricular stiffness included E:e'/end-diastolic volume (EDV) and E:early diastolic strain rate/EDV. RESULTS: Of 24 children, 18 were heart transplant recipients. Six control patients had hemodynamically insignificant patent ductus arteriosus or coronary fistula. The mean age was 9.1 ± 5.6 years. Median end-diastolic pressure was 9 mm Hg (interquartile range, 8-13 mm Hg). Lateral E:e'/EDV (r = 0.59, P < .01), septal E:e'/EDV (r = 0.57, P < .01), and (E:circumferential early diastolic strain rate)/EDV (r = 0.54, P < .01) correlated with ß. Lateral E:e'/EDV displayed a C statistic of 0.93 in detecting patients with abnormal LV stiffness (ß > 0.015 mL-1). A lateral E:e'/EDV of >0.15 mL-1 had 89% sensitivity and 93% specificity in detecting an abnormal ß. CONCLUSIONS: Echocardiographic estimates of ventricular stiffness may be accurate compared with the gold standard in pediatric heart transplant recipients. The clinical usefulness of these noninvasive measures in assessing LV stiffness merits further study in children.