Fast-track virtual reality software to facilitate 3-dimensional reconstruction in congenital heart disease.

OBJECTIVES: Two limitations of the clinical use of 3-dimensional (3D) reconstruction and virtual reality systems are the relatively high cost and the amount of experience required to use hardware and software to effectively explore medical images. We have tried to simplify the process and validate a new tool developed for this purpose with a novel software package. METHODS: Five patients with right partial anomalous pulmonary venous return with adequate preoperative images acquired with magnetic resonance imaging were enrolled. Five volunteers with no previous experience in the field of 3D reconstruction were instructed to use the software after viewing a short video tutorial. Users were then asked to create a 3D model of each patient's heart using DIVA software. Their results were compared quantitatively and qualitatively with a benchmark reconstruction performed by an experienced user. RESULTS: All our participants recreated 3D models in a relatively short time, maintaining a good overall quality (average quality score ≥ 3 on a scale of 1-5). The overall trend of all the parameters analysed showed a statistical improvement between case 1 and case 5, as users became more and more experienced. CONCLUSIONS: DIVA is a simple software program that allows accurate 3D reconstruction in a relatively short time ("fast-track" virtual reality). In this study, we demonstrated the potential use of DIVA by inexperienced users, with a significant improvement in quality and time after a few cases were performed. Further studies are needed to confirm the potential application of this technology on a larger scale.

Exercise electrocardiogram for risk-based screening of severe residual coronary lesion in children after coronary surgery.

BACKGROUND: Residual severe coronary artery (CA) lesion (SCL) in children after cardiac surgery involving the CA is a major concern. AIM: To evaluate the value of exercise electrocardiogram (eECG) for risk-based screening of SCL. METHODS: We analysed 135 maximal eECG from 115 children (mean age 13.6±3.7 years) who underwent concomitant CA imaging. SCL was defined as a stenosis exceeding 50%. RESULTS: Underlying congenital heart diseases were transposition of the great arteries (TGA) (n = 116), CA pathway anomaly (n = 13) and left CA from the pulmonary artery (n = 6). Eleven SCLs were identified in 10 patients, of which 3 had a known untreated non-severe lesion and 4 had no lesions on previous imaging. In multivariable analysis, risks markers for SCL were effort chest pain (OR: 4.72, 95% CI: 1.23-18.17; P=0.024), intramural pathway (OR: 4.37, 95% CI: 1.14-16.81; P=0.032). Yacoubs C-type CA was added as a risk marker for patients with TGA (P=0.0009). All patients with SCL had a positive eECG (sensitivity: 100%, 95% CI: 72-100). Specificity was 81% (95% CI: 73-87). In the low-risk group (0 risk markers), 3/95 patients had SCL (3%), and the post-test probability of SCL with positive eECG (PPr+) was 15% (95% CI: 8-21). In the high-risk group (≥1 risk marker) comprising 8/40 SCLs (20%), PPr+ was 53% (95% CI: 35-67). CONCLUSIONS: Most SCL tended to develop gradually, years after surgery. Provided it is near maximal, a negative eECG appears sufficient to exclude SCL. In the high-risk group, PPr+ exceeded 50%.

Fast-track virtual reality for cardiac imaging in congenital heart disease.

BACKGROUND AND AIM OF THE STUDY: We sought to evaluate the appropriateness of cardiac anatomy renderings by a new virtual reality (VR) technology, entitled DIVA, directly applicable to raw magnetic resonance imaging (MRI) data without intermediate segmentation steps in comparison to standard three-dimensional (3D) rendering techniques (3D PDF and 3D printing). Differences in post-processing times were also evaluated. METHODS: We reconstructed 3D (STL, 3D-PDF, and 3D printed ones) and VR models of three patients with different types of complex congenital heart disease (CHD). We then asked a senior pediatric heart surgeon to compare and grade the results obtained. RESULTS: All anatomical structures were well visualized in both VR and 3D PDF/printed models. Ventricular-arterial connections and their relationship with the great vessels were better visualized with the VR model (Case 2); aortic arch anatomy and details were also better visualized by the VR model (Case 3). The median post-processing time to get VR models using DIVA was 5 min in comparison to 8 h (range 8-12 h including printing time) for 3D models (PDF/printed). CONCLUSIONS: VR directly applied to non-segmented 3D-MRI data set is a promising technique for 3D advanced modeling in CHD. It is systematically more consistent and faster when compared to standard 3D-modeling techniques.

New Approach to Accelerated Image Annotation by Leveraging Virtual Reality and Cloud Computing.

Three-dimensional imaging is at the core of medical imaging and is becoming a standard in biological research. As a result, there is an increasing need to visualize, analyze and interact with data in a natural three-dimensional context. By combining stereoscopy and motion tracking, commercial virtual reality (VR) headsets provide a solution to this critical visualization challenge by allowing users to view volumetric image stacks in a highly intuitive fashion. While optimizing the visualization and interaction process in VR remains an active topic, one of the most pressing issue is how to utilize VR for annotation and analysis of data. Annotating data is often a required step for training machine learning algorithms. For example, enhancing the ability to annotate complex three-dimensional data in biological research as newly acquired data may come in limited quantities. Similarly, medical data annotation is often time-consuming and requires expert knowledge to identify structures of interest correctly. Moreover, simultaneous data analysis and visualization in VR is computationally demanding. Here, we introduce a new procedure to visualize, interact, annotate and analyze data by combining VR with cloud computing. VR is leveraged to provide natural interactions with volumetric representations of experimental imaging data. In parallel, cloud computing performs costly computations to accelerate the data annotation with minimal input required from the user. We demonstrate multiple proof-of-concept applications of our approach on volumetric fluorescent microscopy images of mouse neurons and tumor or organ annotations in medical images.

Predictors of low exercise cardiac output in patients with severe pulmonic regurgitation.

BACKGROUND AND OBJECTIVES: Chronic pulmonic regurgitation (PR) following repair of congenital heart disease (CHD) impairs right ventricular function that impacts peak exercise cardiac index (pCI). We aimed to estimate in a non-invasive way pCI and peak oxygen consumption (pVO2) and to evaluate predictors of low pCI in patients with significant residual pulmonic regurgitation after CHD repair. METHOD: We included 82 patients (median age 19 years (range 10-54 years)) with residual pulmonic regurgitation fraction >40%. All underwent cardiac MRI and cardiopulmonary testing with measurement of pCI by thoracic impedancemetry. Low pCI was defined <7 L/min/m2. RESULTS: Low pCI was found in 18/82 patients. Peak indexed stroke volume (pSVi) tended to compensate chronotropic insufficiency only in patients with normal pCI (r=-0.31, p=0.01). Below 20 years of age, only 5/45 patients had low pCI but near-normal (≥6.5 L/min/m2). pVO2 (mL/kg/min) was correlated with pCI (r=0.58, p=0.0002) only in patients aged >20 years. Left ventricular stroke volume in MRI correlated with pSVi only in the group of patients with low pCI (r=0.54, p=0.02). No MRI measurements predicted low pCI. In multivariable analysis, only age predicted a low pCI (OR=1.082, 95% CI 1.035 to 1.131, p=0.001) with continuous increase of risk with age. CONCLUSIONS: In patients with severe PR, pVO2 is a partial reflection of pCI. Risk of low pCI increases with age. No resting MRI measurement predicts low haemodynamic response to exercise. Probably more suitable to detect ventricular dysfunction, pCI measurement could be an additional parameter to take into account when considering pulmonic valve replacement.

Prognostic Value of Magnetic Resonance Phenotype in Patients With Arrhythmogenic Right Ventricular Cardiomyopathy.

BACKGROUND: Cardiac magnetic resonance (CMR) is widely used to assess tissue and functional abnormalities in arrhythmogenic right ventricular cardiomyopathy (ARVC). Recently, a ARVC risk score was proposed to predict the 5-year risk of malignant ventricular arrhythmias in patients with ARVC. However, CMR features such as fibrosis, fat infiltration, and left ventricular (LV) involvement were not considered. OBJECTIVES: The authors sought to evaluate the prognostic role of CMR phenotype in patients with definite ARVC and to evaluate the effectiveness of the novel 5-year ARVC risk score to predict cardiac events in different CMR presentations. METHODS: A total of 140 patients with definite ARVC were enrolled (mean age 42 ± 17 years, 97 males) in this multicenter prospective registry. As per study design, CMR was performed in all the patients at enrollment. The novel 5-year ARVC risk score was retrospectively calculated using the patient's characteristics at the time of enrollment. During a median follow-up of 5 years (2 to 8 years), the combined endpoint of sudden cardiac death, appropriate implantable cardioverter-defibrillator intervention, and aborted cardiac arrest was considered. RESULTS: CMR was completely negative in 14 patients (10%), isolated right ventricular (RV) involvement was found in 58 (41%), biventricular in 52 (37%), and LV dominant in 16 (12%). During the follow-up, 48 patients (34%) had major events, but none occurred in patients with negative CMR. At Kaplan-Meier analysis, patients with LV involvement (LV dominant and biventricular) had a worse prognosis than those with lone RV (p < 0.0001). At multivariate analysis, the LV involvement, a LV-dominant phenotype, and the 5-year ARVC risk score were independent predictors of major events. The estimated 5-year risk was able to predict the observed risk in patients with lone RV but underestimated the risk in those with LV involvement. CONCLUSIONS: Different CMR presentations of ARVC are associated with different prognoses. The 5-year ARVC risk score is valid for the estimation of risk in patients with lone-RV presentation but underestimated the risk when LV is involved.

Long-Term Exposure to Elevated Systolic Blood Pressure in Predicting Incident Cardiovascular Disease: Evidence From Large-Scale Routine Electronic Health Records.

Background How measures of long-term exposure to elevated blood pressure might add to the performance of "current" blood pressure in predicting future cardiovascular disease is unclear. We compared incident cardiovascular disease risk prediction using past, current, and usual systolic blood pressure alone or in combination. Methods and Results Using data from UK primary care linked electronic health records, we applied a landmark cohort study design and identified 80 964 people, aged 50 years (derivation cohort=64 772; validation cohort=16 192), who, at study entry, had recorded blood pressure, no prior cardiovascular disease, and no previous antihypertensive or lipid-lowering prescriptions. We used systolic blood pressure recorded up to 10 years before baseline to estimate past systolic blood pressure (mean, time-weighted mean, and variability) and usual systolic blood pressure (correcting current values for past time-dependent blood pressure fluctuations) and examined their prospective relation with incident cardiovascular disease (first hospitalization for or death from coronary heart disease or stroke/transient ischemic attack). We used Cox regression to estimate hazard ratios and applied Bayesian analysis within a machine learning framework in model development and validation. Predictive performance of models was assessed using discrimination (area under the receiver operating characteristic curve) and calibration metrics. We found that elevated past, current, and usual systolic blood pressure values were separately and independently associated with increased incident cardiovascular disease risk. When used alone, the hazard ratio (95% credible interval) per 20-mm Hg increase in current systolic blood pressure was 1.22 (1.18-1.30), but associations were stronger for past systolic blood pressure (mean and time-weighted mean) and usual systolic blood pressure (hazard ratio ranging from 1.39-1.45). The area under the receiver operating characteristic curve for a model that included current systolic blood pressure, sex, smoking, deprivation, diabetes mellitus, and lipid profile was 0.747 (95% credible interval, 0.722-0.811). The addition of past systolic blood pressure mean, time-weighted mean, or variability to this model increased the area under the receiver operating characteristic curve (95% credible interval) to 0.750 (0.727-0.811), 0.750 (0.726-0.811), and 0.748 (0.723-0.811), respectively, with all models showing good calibration. Similar small improvements in area under the receiver operating characteristic curve were observed when testing models on the validation cohort, in sex-stratified analyses, or by using different landmark ages (40 or 60 years). Conclusions Using multiple blood pressure recordings from patients' electronic health records showed stronger associations with incident cardiovascular disease than a single blood pressure measurement, but their addition to multivariate risk prediction models had negligible effects on model performance.

Aortic atresia and interrupted aortic arch communicating through external carotid anastomosis.

We describe the case of a newborn girl who displayed association of aortic atresia and interrupted aortic arch, with retrograde flow in ascending aorta, through extracranial anastomoses between vertebral arteries (arisen from descending aorta) and external carotids.

Aortic angle is associated with neo-aortic root dilatation and regurgitation following arterial switch operation.

INTRODUCTION: Neo-aortic root dilatation and regurgitation are common progressive long-term complications of the arterial switch operation (ASO) for transposition of the great arteries (TGA) with increasing clinical burden. While several risk factors have been identified, most are constitutional. The acute aortic angle commonly seen after ASO might alter aortic dynamics and facilitate progression of the neo-aortic root dilatation and aortic regurgitation, but insufficient data is available. We intend to assess the effect of the aortic angle in the extent of neo-aortic root dilatation and presence of regurgitation. METHODS: Retrospective analysis of TGA patients undergoing CMR after ASO at a single tertiary centre from November 2010 to July 2017. RESULTS: 180 patients were analysed, 157 of which having adequate imaging of the aortic arch and root. Neo-aortic root Z score was normally distributed with 73% of patients having a Z score > 2. The aortic angle had a significant (p < 0,001) inverse relationship with the neo-aortic root Z score both in univariate and multivariate linear regression. Other significant associations were male gender and the concomitant presence of a VSD or a dysplastic neo-aortic valve. The presence of neo-aortic regurgitation was also inversely correlated with the aortic angle. The presence of a bicuspid neo-aortic valve was another significant association, further correlating with the more severe forms. CONCLUSIONS: Acute aortic angles associate more extensive neo-aortic root dilatation and higher incidence of regurgitation. We believe a surgical technique promoting less acute aortic angles has potential for ameliorating the long-term outcomes of TGA.

Myocardial inflammation detected by cardiac MRI in Arrhythmogenic right ventricular cardiomyopathy: A paediatric case series.

INTRODUCTION: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited myocardial disease with an elusive association with myocardial inflammation. A myocarditis phenotype has been well established without systematic evidence of a viral trigger. We intend to study the relationship between myocardial inflammation detected by Cardiac magnetic resonance (CMR) and ARVC in a paediatric population. METHODS: Retrospective case series of all patients <18 years admitted to two CMR units for clinical suspicion of myocarditis from March 2012 to June 2017 who had genetic testing for inherited cardiomyopathies including analysis for known ARVC genes. RESULTS: Six patients were identified experiencing myocarditis-like episodes with chest pain and troponin elevation. All had CMR evidence of active myocardial inflammation often affecting the left ventricle without identification of an infectious trigger. These episodes were likely exercise-induced in 50% of our patients and were multiple in all but one. CONCLUSION: We provide evidence that ARVC can present as recurrent myocarditis-like episodes with CMR evidence of myocardial inflammation despite absent infectious trigger in children. We believe they represent an active hot phase of the disease and may lead to disease progression.

Vascular anatomy in children with univentricular hearts regarding transcatheter bidirectional Glenn anastomosis.

BACKGROUND: Transcatheter stent-secured Glenn anastomosis, aiming to reduce the invasiveness of palliation in patients with univentricular heart defects, has been reported in large experimental animals. The advent of biodegradable stents and tissue-engineered vascular grafts will make this procedure a reality in human patients. However, the relationship between the superior vena cava (SVC) and the right pulmonary artery (RPA) is different in humans. AIM: To characterise vascular anatomy in children with univentricular hearts, regarding technical aspects and device design for this procedure. METHODS: Retrospective analysis of 35 thoracic computed tomography angiograms at a mean age of 18.1±22.4 months. RESULTS: Two types of arrangement between the SVC and the RPA were identified: anatomy convenient for immediate wire passage and stent deployment between the two vessels (60%); and pattern of early RPA branching, requiring the perforation wire to traverse the intervascular space to avoid entrance into the upper RPA branch (40%). In patients with the convenient vascular arrangement, the vessels were nearly perpendicular, having immediate contact, with the posterior SVC aspect partially "wrapping" the adjacent RPA in most patients. In patients with early RPA branching, the mean shortest SVC-to-central RPA distance was 4.3±2.7mm. For the total population, the mean length of proximal SVC that allowed stent deployment without covering the brachiocephalic vein was 15.6±5.1mm. CONCLUSIONS: A trumpet-shaped covered stent in a craniocaudal orientation reaching from the SVC into the prebranching RPA seems most suitable for achieving bidirectional Glenn anastomosis percutaneously in humans. However, the short length of the proximal SVC and the presence of early RPA branching pose challenges for optimal design of the dedicated device.

Discordances Between Pre-Natal and Post-Natal Diagnoses of Congenital Heart Diseases and Impact on Care Strategies.

BACKGROUND: Pre-natal diagnosis of congenital heart disease (CHD) allows anticipation of urgent neonatal treatment and provides adequate information to the parents on cardiac outcomes. OBJECTIVES: This study sought to analyze the discordances between expert fetal cardiac diagnosis and final diagnosis of CHD and their impact on neonatal and long-term care strategies. METHODS: We included 1,258 neonates with a pre-natally diagnosed CHD and 189 fetopsies following termination of pregnancy at our tertiary center over a 10-year period. Pre-natal echocardiographic and final diagnoses were compared. RESULTS: For live births, we identified 368 (29.3%) discordances between pre- and post-natal diagnoses. The pre-natal diagnosis was different from the post-natal diagnosis in 36 cases (2.9%) and partially different with a major impact on neonatal treatment of the CHD in 97 cases (7.7%). In 235 cases (18.7%), the diagnosis was partially different with no impact on neonatal planned treatment. The discordances had a negative impact on late care strategy in 62 cases (4.9%): more complex CHD that was unsuitable for biventricular repair, leading to unplanned compassionate care, additional surgery or increase of the complexity level of the Aristotle score. A positive impact was found in 31 cases (2.5%): less complex CHD that allowed biventricular repair, fewer surgical procedures, or decrease of the complexity of the Aristotle score. For 275 patients (21.9%), there was no impact on late care strategy. Of the 872 terminations of pregnancy and intrauterine fetal deaths, 189 fetopsies were available: 16 (8.5%) different diagnoses, 27 (14.3%) major differences, and 60 (31.7%) minor differences. CONCLUSIONS: Correcting fetal cardiac diagnosis after birth can lead to significant changes in neonatal (10.6%) and late (7.4%) care strategies. Tools should be developed to try to improve the accuracy of pre-natal diagnosis of CHD. Clinicians should be cautious when predicting required treatment and outcomes during pre-natal counseling.

Computed tomography imaging in children with congenital heart disease: Indications and radiation dose optimization.

Computed tomography (CT) technology is acquiring a key role in the diagnostic process of complex cardiac congenital anomalies. Recent advances and improvements in spatial and temporal resolution and radiation dose are encouraging the use of CT scanning in children. Paediatric cardiologists should have a good knowledge of the potential of CT techniques and their limitations to plan and properly perform CT examinations without forgetting radiation concerns. In this paper, we will discuss the principal indications for CT scans in newborns and children in our clinical practice. We will also outline the most-used strategies for dose reduction. Basic knowledge about the various CT techniques is crucial, not only to perform, but also to interpret CT results, thus helping the medical and surgical management of patients.

Radiation dose reduction in paediatric coronary computed tomography: assessment of effective dose and image quality.

OBJECTIVES: To assess the impact of different protocols on radiation dose and image quality for paediatric coronary computed tomography (cCT). MATERIALS AND METHODS: From January-2012 to June-2014, 140 children who underwent cCT on a 64-slice scanner were included. Two consecutive changes in imaging protocols were performed: 1) the use of adaptive statistical iterative reconstruction (ASIR); 2) the optimization of acquisition parameters. Effective dose (ED) was calculated by conversion of the dose-length product. Image quality was assessed as excellent, good or with significant artefacts. RESULTS: Patients were divided in three age groups: 0-4, 5-7 and 8-18 years. The use of ASIR combined to the adjustment of scan settings allowed a reduction in the median ED of 58 %, 82 % and 85 % in 0-4, 5-7 and 8-18 years group, respectively (7.3 ± 1.4 vs 3.1 ± 0.7 mSv, 5.5 ± 1.6 vs 1 ± 1.9 mSv and 5.3 ± 5.0 vs 0.8 ± 2.0 mSv, all p < 0,05). Prospective protocol was used in 51 % of children. The reduction in radiation dose was not associated with reduction in diagnostic image quality as assessed by the frequency of coronary segments with excellent or good image quality (88 %). CONCLUSIONS: cCT can be obtained at very low radiation doses in children using ASIR, and prospective acquisition with optimized imaging parameters. KEY POINTS: • Using ASIR allows 25 % to 41 % reduction in the ED. • Prospective protocol is used up to 51 % of children after premedication. • Low dose is possible using ASIR and optimized prospective paediatric cCT.

Problems in the diagnosis of discordant atrioventricular with concordant ventriculo-arterial connections: anatomical considerations, surgical management, and long-term outcome.

BACKGROUND: Discordant atrioventricular with concordant ventriculo-arterial connections is a rare cardiac defect. When isolated, the haemodynamics resemble transposition of the great arteries. In complex heart defects such as heterotaxy, haemodynamics guide the surgical approach. OBJECTIVE: To report a series of eight patients with discordant atrioventricular and concordant ventriculo-arterial connections focussing on anatomical and diagnostic difficulties, surgical management, and follow-up. METHODS: A retrospective review was carried out from 1983 to 2013. Anatomical description was based on segmental analysis. Emphasis was placed on the venoatrial connections. RESULTS: Segmental arrangement was {I, D, S} in six patients, all with spiralling great vessels. There were two patients with parallel great vessels of whom one had {S, L, D} and the other had {S, L, A} arrangement. Of eight patients, five had heterotaxy syndrome. Median age at repair surgery was 1.4 years (with a range from 1.1 months to 8.1 years). The repair surgery finally performed was the atrial switch procedure in seven out of eight patients. The main post-operative complications were two cases of baffle obstruction and one sick sinus syndrome needing pacemaker implantation. There were two early post-operative deaths and six late survivors. Median follow-up was 4.2 years (with a range from 3.9 to 26.7 years) with good functional status in all survivors. Discussion Diagnosing discordant atrioventricular with concordant ventriculo-arterial connections remains challenging. There are ongoing controversies about the definition of atrial morphology and heterotaxy syndrome animating the anatomic discussion of these complex heart defects. Haemodynamically, the atrial switch procedure is the surgical method of choice with an encouraging long-term follow-up despite rhythm disturbances and baffle obstruction.

Congenital supravalvar mitral ring: an underestimated anomaly.

OBJECTIVE: Congenital mitral ring is a rare subtype of congenital mitral stenosis. Our objective is to review the anatomic findings and surgical results of this lesion and to identify early predictors of outcome. METHODS: Clinical reports, echocardiographic studies, cardiac catheterizations, surgical reports, and follow-up data of all patients with mitral ring diagnosed at the Bambino Gesù Hospital were retrospectively reviewed. RESULTS: Between January of 1987 and June of 2007, a mitral ring was diagnosed in 25 patients (13 male) with a mean age at diagnosis of 36 months. The ring was identified in a single neonate but seemed to develop and progress during infancy. All but 1 patient had associated cardiac anomalies. We identified 2 distinct subtypes: "intramitral ring" in 18 of 25 patients (72%), associated with complex valve pathology and a worse outcome, and "supramitral ring" in 7 of 25 patients (18%), in whom the mitral apparatus was usually normal and the outcome was better. The ring was surgically removed in 13 of 25 patients (52%) (mean Doppler gradient 15 +/- 4 mm Hg). The gradient decreased in 9 of 13 patients (mean diastolic transmitral gradient 8 mm Hg) in the other 4 patients, all with intramitral ring. All 4 patients underwent repeat mitral valvuloplasty. There were no operative or late deaths. CONCLUSION: Two types of congenital mitral ring, with diverse valve pathology and outcome, were identified. Rarely seen in neonates, the ring develops and often progresses during infancy. Recognition is important because surgical results are better than for other forms of congenital mitral stenosis.