Combining patient-specific, digital 3D models with tele-education for adolescents with CHD.

INTRODUCTION: Adolescents with CHD require transition to specialised adult-centred care. Previous studies have shown that adolescents' knowledge of their medical condition is correlated with transition readiness. Three-dimensional printed models of CHD have been used to educate medical trainees and patients, although no studies have focused on adolescents with CHD. This study investigates the feasibility of combining patient-specific, digital 3D heart models with tele-education interventions to improve the medical knowledge of adolescents with CHD. METHODS: Adolescent patients with CHD, aged between 13 and 18 years old, were enrolled and scheduled for a tele-education session. Patient-specific digital 3D heart models were created using images from clinically indicated cardiac magnetic resonance studies. The tele-education session was performed using commercially available, web-conferencing software (Zoom, Zoom Video Communications Inc.) and a customised software (Cardiac Review 3D, Indicated Inc.) incorporating an interactive display of the digital 3D heart model. Medical knowledge was assessed using pre- and post-session questionnaires that were scored by independent reviewers. RESULTS: Twenty-two adolescents completed the study. The average age of patients was 16 years old (standard deviation 1.5 years) and 56% of patients identified as female. Patients had a variety of cardiac defects, including tetralogy of Fallot, transposition of great arteries, and coarctation of aorta. Post-intervention, adolescents' medical knowledge of their cardiac defects and cardiac surgeries improved compared to pre-intervention (p < 0.01). CONCLUSIONS: Combining patient-specific, digital 3D heart models with tele-education sessions can improve adolescents' medical knowledge and may assist with transition to adult-centred care.

Normal right and left ventricular volumes prospectively obtained from cardiovascular magnetic resonance in awake, healthy, 0- 12 year old children.

INTRODUCTION: Pediatric z scores are necessary to describe size and structure of the heart in growing children, however, development of an accurate z score calculator requires robust normal datasets, which are difficult to obtain with cardiovascular magnetic resonance (CMR) in children. Motion-corrected (MOCO) cines from re-binned, reconstructed real-time cine offer a free-breathing, rapid acquisition resulting in cines with high spatial and temporal resolution. In combination with child-friendly positioning and entertainment, MOCO cine technique allows for rapid cine volumetry in patients of all ages without sedation. Thus, our aim was to prospectively enroll normal infants and children birth-12 years for creation and validation of a z score calculator describing normal right ventricular (RV) and left ventricular (LV) size. METHODS: With IRB approval and consent/assent, 149 normal children successfully underwent a brief noncontrast CMR on a 1.5 T scanner including MOCO cines in the short axis, and RV and LV volumes were measured. 20% of scans were re-measured for interobserver variability analyses. A general linear modeling (GLM) framework was employed to identify and properly represent the relationship between CMR-based assessments and anthropometric data. Scatter plots of model fit and Akaike's information criteria (AIC) results were used to guide the choice among alternative models. RESULTS: A total of 149 subjects aged 22 days-12 years (average 5.1 ± 3.6 years), with body surface area (BSA) range 0.21-1.63 m2 (average 0.8 ± 0.35 m2) were scanned. All ICC values were > 95%, reflecting excellent agreement between raters. The model that provided the best fit of volume measure to the data included BSA with higher order effects and gender as independent variables. Compared with earlier z score models, there is important additional growth inflection in early toddlerhood with similar z score prediction in later childhood. CONCLUSIONS: Free-breathing, MOCO cines allow for accurate, reliable RV and LV volumetry in a wide range of infants and children while awake. Equations predicting fit between LV and RV normal values and BSA are reported herein for purposes of creating z scores. TRIAL REGISTRATION: clinicaltrials.gov NCT02892136, Registered 7/21/2016.

Troponin I Levels Correlate with Cardiac MR LGE and Native T1 Values in Duchenne Muscular Dystrophy Cardiomyopathy and Identify Early Disease Progression.

Cardiomyopathy is the leading cause of death in Duchenne muscular dystrophy (DMD). Elevated troponin levels are observed in DMD and may vary with disease progression. We studied troponin levels in DMD related to cardiac fibrosis and native T1 measures. This is a prospective, cross-sectional, observational study of 30 DMD subjects measuring native T1 levels and late gadolinium enhancement (LGE) on cardiac MR imaging (CMR) correlated with temporally associated serum troponin I levels. Non-parametric analyses including Spearman correlations and Kruskal-Wallis test were performed between groups. p values resulting from the pair-wise comparisons were adjusted for multiple comparisons using the Sidak method where appropriate. There were 15 DMD subjects with no LGE (age 12 ± 3 yo; EF% 60 ± 5) and troponin I level of 0.05 ± 0.08 ng/ml, of which three had an abnormal troponin level (over 0.04 ng/ml); 7 DMD subjects with mild LGE (age 17 ± 5 yo, EF% 52 ± 8) and troponin I level of 0.28 ± 0.36 ng/ml, of which five had an abnormal troponin level; and 8 DMD subjects with moderate-to-severe LGE (age 16 ± 6 yo; EF% 54 ± 8) and troponin I level of 0.11 ± 0.14 ng/ml, of which four had an abnormal troponin level. Troponin I levels in DMD subjects with mild LGE was significantly increased compared to subjects with no LGE (p = 0.02). There was a statistically significant positive correlation between troponin I levels and MOLLI septal native T1 values (r2 = 0.173, p = 0.02). Overall, MOLLI lateral native T1 levels were increased with moderate-severe LGE compared to mild and none (p < 0.01). Serum biomarker troponin I levels were increased in DMD subjects with mild LGE and correlated with MOLLI septal native T1 values. Troponin I levels may be a useful minimally invasive outcome marker to monitor myocardial disease progression in DMD cardiomyopathy.

X-ray fused with MRI guidance of pre-selected transcatheter congenital heart disease interventions.

OBJECTIVES: To determine whether X-ray fused with MRI (XFM) is beneficial for select transcatheter congenital heart disease interventions. BACKGROUND: Complex transcatheter interventions often require three-dimensional (3D) soft tissue imaging guidance. Fusion imaging with live X-ray fluoroscopy can potentially improve and simplify procedures. METHODS: Patients referred for select congenital heart disease interventions were prospectively enrolled. Cardiac MRI data was overlaid on live fluoroscopy for procedural guidance. Likert scale operator assessments of value were recorded. Fluoroscopy time, radiation exposure, contrast dose, and procedure time were compared to matched cases from our institutional experience. RESULTS: Forty-six patients were enrolled. Pre-catheterization, same day cardiac MRI findings indicated intervention should be deferred in nine patients. XFM-guided cardiac catheterization was performed in 37 (median age 8.7 years [0.5-63 years]; median weight 28 kg [5.6-110 kg]) with the following prespecified indications: pulmonary artery (PA) stenosis (n = 13), aortic coarctation (n = 12), conduit stenosis/insufficiency (n = 9), and ventricular septal defect (n = 3). Diagnostic catheterization showed intervention was not indicated in 12 additional cases. XFM-guided intervention was performed in the remaining 25. Fluoroscopy time was shorter for XFM-guided intervention cases compared to matched controls. There was no significant difference in radiation dose area product, contrast volume, or procedure time. Operator Likert scores indicated XFM provided useful soft tissue guidance in all cases and was never misleading. CONCLUSIONS: XFM provides operators with meaningful three-dimensional soft tissue data and reduces fluoroscopy time in select congenital heart disease interventions.

Acute Cardiac MRI Assessment of Radiofrequency Ablation Lesions for Pediatric Ventricular Arrhythmia: Feasibility and Clinical Correlation.

BACKGROUND: Arrhythmia ablation with current techniques is not universally successful. Inadequate ablation lesion formation may be responsible for some arrhythmia recurrences. Periprocedural visualization of ablation lesions may identify inadequate lesions and gaps to guide further ablation and reduce risk of arrhythmia recurrence. METHODS: This feasibility study assessed acute postprocedure ablation lesions by MRI, and correlated these findings with clinical outcomes. Ten pediatric patients who underwent ventricular tachycardia ablation were transferred immediately postablation to a 1.5T MRI scanner and late gadolinium enhancement (LGE) imaging was performed to characterize ablation lesions. Immediate and mid-term arrhythmia recurrences were assessed. RESULTS: Patient characteristics include median age 14 years (1-18 years), median weight 52 kg (11-81 kg), normal cardiac anatomy (n = 6), d-transposition of great arteries post arterial switch repair (n = 2), anomalous coronary artery origin post repair (n = 1), and cardiac rhabdomyoma (n = 1). All patients underwent radiofrequency catheter ablation of ventricular arrhythmia with acute procedural success. LGE was identified at the reported ablation site in 9/10 patients, all arrhythmia-free at median 7 months follow-up. LGE was not visible in 1 patient who had recurrence of frequent premature ventricular contractions within 2 hours, confirmed on Holter at 1 and 21 months post procedure. CONCLUSIONS: Ventricular ablation lesion visibility by MRI in the acute post procedure setting is feasible. Lesions identifiable with MRI may correlate with clinical outcomes. Acute MRI identification of gaps or inadequate lesions may provide the unique temporal opportunity for additional ablation therapy to decrease arrhythmia recurrence.

Radiation-free CMR diagnostic heart catheterization in children.

BACKGROUND: Children with heart disease may require repeated X-Ray cardiac catheterization procedures, are more radiosensitive, and more likely to survive to experience oncologic risks of medical radiation. Cardiovascular magnetic resonance (CMR) is radiation-free and offers information about structure, function, and perfusion but not hemodynamics. We intend to perform complete radiation-free diagnostic right heart catheterization entirely using CMR fluoroscopy guidance in an unselected cohort of pediatric patients; we report the feasibility and safety. METHODS: We performed 50 CMR fluoroscopy guided comprehensive transfemoral right heart catheterizations in 39 pediatric (12.7 ± 4.7 years) subjects referred for clinically indicated cardiac catheterization. CMR guided catheterizations were assessed by completion (success/failure), procedure time, and safety events (catheterization, anesthesia). Pre and post CMR body temperature was recorded. Concurrent invasive hemodynamic and diagnostic CMR data were collected. RESULTS: During a twenty-two month period (3/2015 - 12/2016), enrolled subjects had the following clinical indications: post-heart transplant 33%, shunt 28%, pulmonary hypertension 18%, cardiomyopathy 15%, valvular heart disease 3%, and other 3%. Radiation-free CMR guided right heart catheterization attempts were all successful using passive catheters. In two subjects with septal defects, right and left heart catheterization were performed. There were no complications. One subject had six such procedures. Most subjects (51%) had undergone multiple (5.5 ± 5) previous X-Ray cardiac catheterizations. Retained thoracic surgical or transcatheter implants (36%) did not preclude successful CMR fluoroscopy heart catheterization. During the procedure, two subjects were receiving vasopressor infusions at baseline because of poor cardiac function, and in ten procedures, multiple hemodynamic conditions were tested. CONCLUSIONS: Comprehensive CMR fluoroscopy guided right heart catheterization was feasible and safe in this small cohort of pediatric subjects. This includes subjects with previous metallic implants, those requiring continuous vasopressor medication infusions, and those requiring pharmacologic provocation. Children requiring multiple, serial X-Ray cardiac catheterizations may benefit most from radiation sparing. This is a step toward wholly CMR guided diagnostic (right and left heart) cardiac catheterization and future CMR guided cardiac intervention. TRIAL REGISTRATION: ClinicalTrials.gov NCT02739087 registered February 17, 2016.

Magnetic Resonance Imaging-Guided Cardiac Catheterization Evacuation Drills.

BACKGROUND: The interventional cardiac magnetic resonance imaging suite combines a cardiac catheterization x-ray laboratory with a magnetic resonance imaging suite. At the study institution, interventional cardiac magnetic resonance imaging procedures (ie, magnetic resonance imaging-guided cardiac catheterizations) have been performed under institutional review board-approved research protocols since 2015. Because the workplace incorporates x-ray and magnetic resonance imaging in a highly technical environment, education about the importance of magnet safety is crucial to ensure the safety of patients and staff. OBJECTIVE: To promote magnetic resonance imaging safety and staff preparedness to respond in emergency situations in a specialized interventional cardiac magnetic resonance imaging environment. METHODS: Quarterly in situ evacuation drills with a live volunteer were implemented. A retrospective participant survey using a Likert scale was conducted. Evacuations were timed from the cardiac arrest code alert to safe evacuation or defibrillation if appropriate. RESULTS: Over 4 years, 14 drills were performed. Twenty-nine of 48 participants responded to the survey, a 60% response rate. Most participants agreed or strongly agreed that the drills were a positive experience (90%) and that the drills increased their confidence in their ability to perform in an evacuation scenario (100%). Room evacuation times improved from 71 to 41 seconds. No patient or staff safety events occurred in the interventional cardiac magnetic resonance imaging environment. CONCLUSION: Magnetic resonance imaging-guided cardiac catheterization evacuation drills promote preparedness, ensure patient and staff safety, and improve evacuation time in the interventional cardiac magnetic resonance imaging environment.