Cardiac magnetic resonance predictors for successful primary biventricular repair of unbalanced complete common atrioventricular canal.

BACKGROUND: Patients with unbalanced common atrioventricular canal can be difficult to manage. Surgical planning often depends on pre-operative echocardiographic measurements. We aimed to determine the added utility of cardiac MRI in predicting successful biventricular repair in common atrioventricular canal. METHODS: We conducted a retrospective cohort study of children with common atrioventricular canal who underwent MRI prior to repair. Associations between MRI and echocardiographic measures and surgical outcome were tested using logistic regression, and models were compared using area under the receiver operator characteristic curve. RESULTS: We included 28 patients (median age at MRI: 5.2 months). The optimal MRI model included the novel end-diastolic volume index (using the ratio of left ventricular end-diastolic volume to total end-diastolic volume) and the left ventricle-right ventricle angle in diastole (area under the curve 0.83, p = 0.041). End-diastolic volume index ≤ 0.18 and left ventricle-right ventricle angle in diastole ≤ 72° yield a sensitivity of 83% and specificity of 81% for successful biventricular repair. The optimal multimodality model included the end-diastolic volume index and the echocardiographic atrioventricular valve index with an area under the curve of 0.87 (p = 0.026). CONCLUSIONS: Cardiac MRI can successfully predict successful biventricular repair in patients with unbalanced common atrioventricular canal utilising the end-diastolic volume index alone or in combination with the MRI left ventricle-right ventricle angle in diastole or the echocardiographic atrioventricular valve index. A prospective cardiac MRI study is warranted to better define the multimodality characteristic predictive of successful biventricular surgery.

Aortic growth after arch reconstruction with patch augmentation: a 2-decade experience.

OBJECTIVES: Optimal aortic sizing during aortic arch reconstruction remains unknown. Negative effects of arch under- or oversizing are well-published. We aimed to characterize longitudinal aortic growth after patch-augmented arch reconstruction to identify the initial reconstructed arch size that results in normal mid-term arch dimensions. METHODS: Single-centre, retrospective review of infants undergoing Damus-Kaye-Stansel (DKS) or non-DKS patch-augmented aortic arch reconstruction between 2000 and 2021. Ascending aorta, proximal and distal transverse arch, aortic isthmus (AIsth) and descending aorta dimensions were measured in postoperative echocardiograms (<3 months from index operation) and cross-sectional imaging (>12 months). Longitudinal changes to aortic dimensions and z-scores were analysed. Secondary outcomes included reintervention, valve and ventricular function, mortality and transplantation. RESULTS: Fifty-four patients (16 DKS, 38 non-DKS) were included. At 6.3 [2.2, 12.0]-year follow-up, all aortic segments grew significantly in both groups, while z-scores remained unchanged except for non-DKS proximal and distal transverse arch z-scores, which significantly increased (P < 0.05 each). When stratified by initial postoperative z-score (z < -1, -1 ≤ z ≤ 1, z > 1), non-DKS patients with initial AIsth z-score <-1 had a final z-score significantly smaller than both the targeted z-score zero (P = 0.014) and final z-score in a group with initial postoperative z-score ±1 (P = 0.009). Valve and ventricular function remained stable. Eighteen patients required reintervention, 1 died and 1 underwent transplant. CONCLUSIONS: Over mid-term follow-up, aortic growth after arch reconstruction with patch augmentation was proportional when repaired to normal z-score dimensions, aside from proximal transverse arch, which disproportionately dilated. AIsth undersizing prevailed mid-term and trended towards a higher reintervention rate. Initial reconstruction between z-score 0 and +1 resulted in maintenance of that z-score size at mid-term follow-up. Overall, it is crucial to achieve targeted aortic sizing at index operation to maintain appropriate aortic dimensions over time and reduce reintervention risk with specific focus on the AIsth.

Physical Simulation of Transcatheter Edge-to-Edge Repair using Image-Derived 3D Printed Heart Models.

Background: Transcatheter edge-to-edge valve repair (TEER) is a complex procedure requiring delivery and alignment of the device to the target valve, which can be challenging in atypical or surgically palliated anatomy. We demonstrate application of virtual and physical simulation to plan optimal TEER access and catheter path in normal and congenitally abnormal cardiac anatomy. Methods: Three heart models were created from three-dimensional (3D) images and 3D printed, including two with congenital heart disease. TEER catheter course was simulated both virtually and physically using a commercial TEER system. Results: We demonstrate application of modeling in three patients, including two with congenital heart disease and a Fontan circulation. Access site and pathway to device delivery was simulated by members of a multidisciplinary valve team. Virtual and physical simulation were compared. Conclusions: Virtual and physical simulation of TEER using 3D printed heart models is feasible and may be beneficial for planning and simulation, particularly in patients with complex anatomy. Future work is required to demonstrate application in the clinical setting.

Longitudinal Trends of Vascular Flow and Growth in Patients Undergoing Fontan Operation.

BACKGROUND: Single ventricle (SV) patients undergo multiple surgeries with subsequent changes in anatomy and hemodynamics. There are little cardiac magnetic resonance (CMR) data on serial changes in these patients. This study aimed to assess longitudinal changes of SV anatomy and hemodynamics in a large cohort. METHODS: Anatomy and flow in SV patients with serial CMRs performed between 2008 and 2019 at a single institution were retrospectively reviewed. Mixed-effects linear regression was used to estimate changes over time at 3 to 9 months, 1 to 5 years, and >5 years after Fontan. RESULTS: A total of 119 patients were included (51% with hypoplastic left heart syndrome; 77% underwent extracardiac Fontan). A total of 88 patients had 3 serial CMRs. Indexed right superior vena cava, inferior vena cava, neoaortic valve, and descending aorta area decreased over time (beta = -0.19, -0.44, and -0.23, respectively; P < .01), as did indexed right superior vena cava, neoaorta and native aorta, and descending aorta flow (beta = -0.49, -0.53, and -0.59, respectively; P < .0001). Inferior vena cava flow and its contribution to total caval flow increased (beta = 0.33; P < .0001). Indexed right and left pulmonary artery flow did not change; however, indexed left pulmonary artery area decreased (beta = -0.16; P = .0014) with time. Systemic-to-pulmonary collateral flow remained unchanged before and early after Fontan (beta = -0.54; P = .42) but decreased with time from Fontan (beta = -0.22; P < .0001). CONCLUSIONS: In this cohort of longitudinally followed SV patients, there are significant trends in vascular size and flow over time from Fontan. These findings can be used as a framework to interpret serial CMR data in the SV and noninvasively identify deviations from expected patterns before the development of clinical symptoms.

Free-running cardiac and respiratory motion-resolved 5D whole-heart coronary cardiovascular magnetic resonance angiography in pediatric cardiac patients using ferumoxytol.

BACKGROUND: Coronary cardiovascular magnetic resonance angiography (CCMRA) of congenital heart disease (CHD) in pediatric patients requires accurate planning, adequate sequence parameter adjustments, lengthy scanning sessions, and significant involvement from highly trained personnel. Anesthesia and intubation are commonplace to minimize movements and control respiration in younger subjects. To address the above concerns and provide a single-click imaging solution, we applied our free-running framework for fully self-gated (SG) free-breathing 5D whole-heart CCMRA to CHD patients after ferumoxytol injection. We tested the hypothesis that spatial and motion resolution suffice to visualize coronary artery ostia in a cohort of CHD subjects, both for intubated and free-breathing acquisitions. METHODS: In 18 pediatric CHD patients, non-electrocardiogram (ECG) triggered 5D free-running gradient echo CCMRA with whole-heart 1 mm3 isotropic spatial resolution was performed in seven minutes on a 1.5T CMR scanner. Eleven patients were anesthetized and intubated, while seven were breathing freely without anesthesia. All patients were slowly injected with ferumoxytol (4 mg/kg) over 15 minutes. Cardiac and respiratory motion-resolved 5D images were reconstructed with a fully SG approach. To evaluate the performance of motion resolution, visibility of coronary artery origins was assessed. Intubated and free-breathing patient sub-groups were compared for image quality using coronary artery length and conspicuity as well as lung-liver interface sharpness. RESULTS: Data collection using the free-running framework was successful in all patients in less than 8 min; scan planning was very simple without the need for parameter adjustments, while no ECG lead placement and triggering was required. From the resulting SG 5D motion-resolved reconstructed images, coronary artery origins could be retrospectively extracted in 90% of the cases. These general findings applied to both intubated and free-breathing pediatric patients (no difference in terms of lung-liver interface sharpness), while image quality and coronary conspicuity between both cohorts was very similar. CONCLUSIONS: A simple-to-use push-button framework for 5D whole-heart CCMRA was successfully employed in pediatric CHD patients with ferumoxytol injection. This approach, working without any external gating and for a wide range of heart rates and body sizes provided excellent definition of cardiac anatomy for both intubated and free-breathing patients.

Clinical 3D modeling to guide pediatric cardiothoracic surgery and intervention using 3D printed anatomic models, computer aided design and virtual reality.

BACKGROUND: Surgical and catheter-based interventions for congenital heart disease require precise understanding of complex anatomy. The use of three-dimensional (3D) printing and virtual reality to enhance visuospatial understanding has been well documented, but integration of these methods into routine clinical practice has not been well described. We review the growth and development of a clinical 3D modeling service to inform procedural planning within a high-volume pediatric heart center. METHODS: Clinical 3D modeling was performed using cardiac magnetic resonance (CMR) or computed tomography (CT) derived data. Image segmentation and post-processing was performed using FDA-approved software. Patient-specific anatomy was visualized using 3D printed models, digital flat screen models and virtual reality. Surgical repair options were digitally designed using proprietary and open-source computer aided design (CAD) based modeling tools. RESULTS: From 2018 to 2020 there were 112 individual 3D modeling cases performed, 16 for educational purposes and 96 clinically utilized for procedural planning. Over the 3-year period, demand for clinical modeling tripled and in 2020, 3D modeling was requested in more than one-quarter of STAT category 3, 4 and 5 cases. The most common indications for modeling were complex biventricular repair (n = 30, 31%) and repair of multiple ventricular septal defects (VSD) (n = 11, 12%). CONCLUSIONS: Using a multidisciplinary approach, clinical application of 3D modeling can be seamlessly integrated into pre-procedural care for patients with congenital heart disease. Rapid expansion and increased demand for utilization of these tools within a high-volume center demonstrate the high value conferred on these techniques by surgeons and interventionalists alike.

Sinus venosus defect of the pulmonary vein-type: An easily missed diagnosis.

Atrial septal defects are one of the most common forms of congenital heart disease, however sinus venosus communications, particularly pulmonary vein-type defects, are rare and are easily misdiagnosed. Patients with pulmonary vein-type sinus venosus defects often present earlier than those with ostium secundum defects with significant right heart dilation. Correct diagnosis has important implications for management. We discuss the clinical courses and review multimodality imaging of three patients correctly diagnosed with pulmonary vein-type defects after an initial diagnosis of an ostium secundum atrial septal defect, in order to promote understanding of the unique anatomy of this entity.

Use of Virtual Reality for Hybrid Closure of Multiple Ventricular Septal Defects.

A 28-month-old girl with multiple ventricular septal defects previously underwent surgical and transcatheter attempts at repair. Three-dimensional models were created from cardiac magnetic resonance-derived images. Viewing the models in virtual reality allowed the team to precisely locate the defects and decide on a hybrid transcatheter and surgical approach to ensure successful repair. (Level of Difficulty: Advanced.).

Four-dimensional Multiphase Steady-State MRI with Ferumoxytol Enhancement: Early Multicenter Feasibility in Pediatric Congenital Heart Disease.

Background The value of MRI in pediatric congenital heart disease (CHD) is well recognized; however, the requirement for expert oversight impedes its widespread use. Four-dimensional (4D) multiphase steady-state imaging with contrast enhancement (MUSIC) is a cardiovascular MRI technique that uses ferumoxytol and captures all anatomic features dynamically. Purpose To evaluate multicenter feasibility of 4D MUSIC MRI in pediatric CHD. Materials and Methods In this prospective study, participants with CHD underwent 4D MUSIC MRI at 3.0 T or 1.5 T between 2014 and 2020. From a pool of 460 total studies, an equal number of MRI studies from three sites (n = 60) was chosen for detailed analysis. With use of a five-point scale, the feasibility of 4D MUSIC was scored on the basis of artifacts, image quality, and diagnostic confidence for intracardiac and vascular connections (n = 780). Respiratory motion suppression was assessed by using the signal intensity profile. Bias between 4D MUSIC and two-dimensional (2D) cine imaging was evaluated by using Bland-Altman analysis; 4D MUSIC examination duration was compared with that of the local standard for CHD. Results A total of 206 participants with CHD underwent MRI at 3.0 T, and 254 participants underwent MRI at 1.5 T. Of the 60 MRI examinations chosen for analysis (20 per site; median participant age, 14.4 months [interquartile range, 2.3-49 months]; 33 female participants), 56 (93%) had good or excellent image quality scores across a spectrum of disease complexity (mean score ± standard deviation: 4.3 ± 0.6 for site 1, 4.9 ± 0.3 for site 2, and 4.6 ± 0.7 for site 3; P < .001). Artifact scores were inversely related to image quality (r = -0.88, P < .001) and respiratory motion suppression (P < .001, r = -0.45). Diagnostic confidence was high or definite in 730 of 780 (94%) intracardiac and vascular connections. The correlation between 4D MUSIC and 2D cine ventricular volumes and ejection fraction was high (range of r = 0.72-0.85; P < .001 for all). Compared with local standard MRI, 4D MUSIC reduced the image acquisition time (44 minutes ± 20 vs 12 minutes ± 3, respectively; P < .001). Conclusion Four-dimensional multiphase steady-state imaging with contrast enhancement MRI in pediatric congenital heart disease was feasible in a multicenter setting, shortened the examination time, and simplified the acquisition protocol, independently of disease complexity. Clinical trial registration no. NCT02752191 © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Roest and Lamb in this issue.

Modeling Tool for Rapid Virtual Planning of the Intracardiac Baffle in Double-Outlet Right Ventricle.

PURPOSE: Biventricular repair of double-outlet right ventricle (DORV) necessitates the creation of a complex intracardiac baffle. Creation of the optimal baffle design and placement thereof can be challenging to conceptualize, even with 2-dimensional and 3-dimensional images. This report describes a recently developed methodology for creating virtual baffles to inform intraoperative repair. DESCRIPTION: A total of 3 heart models of DORV were created from cardiac magnetic resonance images. Baffles were created and visualized using custom software. EVALUATION: This report demonstrates application of the tool to virtual planning of the baffle for repair of DORV in 3 cases. Models were examined by a multidisciplinary team, on screen and in virtual reality. Baffles could be rapidly created and revised to facilitate planning of the surgical procedure. CONCLUSIONS: Virtual modeling of the baffle pathway by using cardiac magnetic resonance, creation of physical templates for the baffle, and visualization in virtual reality are feasible and may be beneficial for preoperative planning of complex biventricular repairs in DORV. Further work is needed to demonstrate clinical benefit or improvement in outcomes.

Prevalence and Cause of Early Fontan Complications: Does the Lymphatic Circulation Play a Role?

Background Recent studies suggest that lymphatic congestion plays a role in development of late Fontan complications, such as protein-losing enteropathy. However, the role of the lymphatic circulation in early post-Fontan outcomes is not well defined. Methods and Results This was a retrospective, single-center study of patients undergoing first-time Fontan completion from 2012 to 2017. The primary outcome was early Fontan complication ≤6 months after surgery, a composite of death, Fontan takedown, extracorporeal membrane oxygenation, chest tube drainage >14 days, cardiac catheterization, readmission, or transplant. Complication causes were assigned to 1 of 4 groups: (1) Fontan circuit obstruction, (2) ventricular dysfunction or atrioventricular valve regurgitation, (3) persistent pleural effusions in the absence of Fontan obstruction or ventricular dysfunction, and (4) chylothorax or plastic bronchitis. T2-weighted magnetic resonance imaging sequences were used to assess for lymphatic perfusion abnormality. The cohort consisted of 238 patients. Fifty-eight (24%) developed early complications: 20 of 58 (34.5%) in group 1, 8 of 58 (14%) in group 2, 18 of 58 (31%) in group 3, and 12 of 58 (20%) in group 4. Preoperative T2 imaging was available for 126 (53%) patients. Patients with high-grade lymphatic abnormalities had 6 times greater odds of developing early complications (P=0.001). Conclusions There is substantial morbidity in the early post-Fontan period. Half of those who developed early complications had lymphatic failure or persistent effusions unrelated to structural or functional abnormalities. Preoperative T2 imaging demonstrated that patients with higher-grade lymphatic perfusion abnormalities were significantly more likely to develop early complications. This has implications for risk stratification and optimization of patients before Fontan palliation.

Accuracy of transesophageal echocardiography in the identification of postoperative intramural ventricular septal defects.

BACKGROUND: Intramural ventricular septal defects (VSDs), residual interventricular communications occurring after repair of conotruncal defects, are associated with poor postoperative outcomes. The ability of intraoperative transesophageal echocardiography (TEE) to identify intramural VSDs has not yet been evaluated. METHODS: Intraoperative TEE and postoperative transthoracic echocardiography (TTE) data in all patients undergoing all biventricular repair of conotruncal anomalies in our hospital between January 1, 2006, and June 30, 2013, were reviewed. The ability of TEE to accurately identify residual defects was assessed using postoperative TTE as the reference imaging modality. RESULTS: Intramural VSDs occurred in 34 of 337 patients evaluated; 19 were identified by both TTE and TEE, and 15 were identified by TTE only. Sensitivity was 56% and specificity was 100% for TEE to identify intramural VSDs. Peripatch VSDs were identified in 90 patients by both TTE and TEE, in 53 by TTE only, and in 15 by TEE only, yielding a sensitivity of 63% and specificity of 92%. Of the VSDs requiring catheterization or surgical reintervention, 6 of 7 intramural VSDs and all 5 peripatch VSDs were identified by intraoperative TEE. TEE guided the intraoperative decision to return to cardiopulmonary bypass (CPB) in an attempt to close residual defects in 12 patients with intramural VSDs and in 4 patients with peripatch VSDs seen after initial CPB; of these, 10 intramural VSDs and all 4 peripatch VSDs resolved or became smaller on final intraoperative TEE. CONCLUSIONS: TEE has modest sensitivity but high specificity for identifying intramural VSDs and can detect most defects requiring reintervention. Repeat attempts at closure in the index operation may successfully correct intramural VSDs identified by TEE.

Intramural Ventricular Septal Defect Is a Distinct Clinical Entity Associated With Postoperative Morbidity in Children After Repair of Conotruncal Anomalies.

BACKGROUND: Intramural ventricular septal defects (VSDs) are interventricular communications through right ventricular free wall trabeculations that can occur after repair of conotruncal anomalies. We assessed the prevalence of residual intramural VSDs and their effect on postoperative course. METHODS AND RESULTS: Children who underwent biventricular repair of a conotruncal anomaly from January 1, 2006, to June 30, 2013, and had a postoperative transthoracic echocardiogram were included. Images were reviewed for residual intramural or nonintramural VSDs. The primary outcome was a composite of mortality, extracorporeal membrane oxygenation use, and need for subsequent catheter or surgical VSD closure. The secondary outcome was postoperative hospital length of stay. A residual VSD was present in 256 of the 442 subjects (58%), of which 231 (90%) were <2 mm in size. Forty-nine patients (11%) had intramural VSDs, and 207 (47%) had nonintramural VSDs. Patients with intramural VSDs were more likely to reach the primary composite outcome compared with those with nonintramural VSDs or no residual VSD (14 of 49 [29%] versus 15 of 207 [7%] versus 6 of 186 [3%]; P<0.0001). In addition, those with intramural VSDs had longer postoperative hospital length of stay compared with those with nonintramural VSDs or no residual VSD (20 days [interquartile range, 11-42 days] versus 7 days [interquartile range, 5-14 days] versus 6 days [interquartile range, 4-11 days]; P=0.0001). These associations remained significant after adjustment for known risk factors for poor outcomes, including residual VSD size and operative complexity. CONCLUSIONS: Among residual VSDs after repair of conotruncal anomalies, intramural VSDs are uniquely associated with postoperative morbidity, mortality, and longer postoperative hospital length of stay. It is important to recognize intramural VSDs in the postoperative period.

The prevalence of arrhythmias, predictors for arrhythmias, and safety of exercise stress testing in children.

Exercise testing is commonly performed in children for evaluation of cardiac disease. Few data exist, however, on the prevalence, types of arrhythmias, predictors for arrhythmias, and safety of exercise testing in children. A retrospective review of all patients ≤21 years undergoing exercise testing at our center from 2008 to 2012 was performed. Patients with clinically relevant arrhythmias were compared to those not experiencing a significant arrhythmia. 1,037 tests were performed in 916 patients. The mean age was 14 ± 4 years, 537 (55 %) were male, 281 (27 %) had congenital heart disease, 178 (17 %) had a history of a prior arrhythmia, and 17 (2 %) had a pacemaker or ICD. 291 (28 %) patients had a rhythm disturbance during the procedure. Clinically important arrhythmias were noted in 34 (3 %) patients and included: 19 (1.8 %) increasing ectopy with exercise, 5 (0.5 %) VT, 5 (0.5 %) second degree AV block, 3 (0.3 %) SVT, and 2 (0.2 %) AFIB. On multivariate logistic regression, variables associated with the development of clinically relevant arrhythmias included severe left ventricular (LV) dysfunction on echo (OR 1.99, CI 1.20-3.30) and prior history of a documented arrhythmia (OR 2.94, CI 1.25-6.88). There were no adverse events related to testing with no patient requiring cardioversion, defibrillation, or acute anti-arrhythmic therapy. A total of 28 % of children developed a rhythm disturbance during exercise testing and 3 % were clinically important. Severe LV dysfunction and a history of documented arrhythmia were associated with the development of a clinically important arrhythmia.