Faculty Bibliography

Background: Complex ventricular-arterial (VA) relationships in patients with double outlet right ventricle (DORV) make preoperative assessment of potential repair pathways challenging. The relationship of the ventricular septal defect (VSD) to one or both great arteries must be understood and this influences the choice of surgical procedure [1] In neonates and infants with DORV, Computed Tomography (CT) is often performed due to the ability to get high spatial resolution and ECG gated images [2], however it is possible to get the necessary information from Magnetic Resonance (MR) imaging with an added advantage of avoiding exposure to ionizing radiation. Both CT and MR allow image acquisition in three dimensions (3D) but traditional viewing of the anatomy using the multiplanar reformatting is actually done in two dimensions (2D). Volume rendering from either modality may also be performed, but typically only the external vascular anatomy is depicted. We hypothesized that it is possible to accurately define the intracardiac anatomy in infants with DORV using virtual and physical 3D printed (rapid prototyped) models created from either MR or CT and this can both aid in better defining potential VA pathways and may assist in surgical decision making. Methods: Virtual and physical 3D models were generated for three patients with DORV. Non-ECG-gated 3D spoiled fast gradient echo sequence MR angiography was used for two patients. Retrospective ECG gated CT angiography images acquired in diastole were used in the third patient (to better define the coronary arteries given the suspicion of a single coronary artery by echocardiography). Blood pool segmentation (Figure 1a) was performed in all the three patients (Mimics, Materialise, Leuven, Belgium). A 2 mm shell was added to the blood pool and it was hollowed to create a patient specific heart replica (3-matic, Materialise, Leuven, Belgium). All virtual models were cut to best demonstrate the VA relationships and the models were printed. Results: The VSD and VA relationships were well visualized in all three patients using both the virtual and physical models (Figure 1b,c). The models helped the surgeons better understand the anatomy in all patients: in two patients the surgical plan was altered while the plan was confirmed in the third patient (Table 1). Conclusions: Construction of 3D models in patients with DORV is feasible and allows for extensive examination and surgical planning. This may facilitate a focused and informed surgical procedure and improve the potential for successful outcome. For purposes of DORV, non-gated MRA is sufficient to delineate the VA relationships adequately for 3D printing and enhanced clinical decision-making. CT imaging should be reserved for only those patients where additional information like coronary artery anatomy is desired

Background: Three-dimensional (3D) virtual models are valuable tools that may help to better understand complex cardiovascular anatomy and facilitate surgical planning in patients with congenital heart disease (CHD). Although computed tomography (CT) images are used most commonly to create these models [1,2], Magnetic Resonance Imaging (MRI) may be an attractive alternative, since it offers superior soft-tissue characterization and flexible image contrast mechanisms, and avoids the use of ionizing radiation. However, segmentation on MRI images is inherently challenging due to noise/artifacts, magnetic field inhomogeneity, and relatively lower spatial resolution compared to CT. The purpose of this study was to evaluate the image quality and assess the feasibility of creating virtual 3D heart models using a novel prototype 3D whole heart self-navigated radial MRI technique. Methods: Free-breathing self-navigated whole heart MRI was performed on three pediatric patients: two with complex CHD (average age=17 months) and one with normal cardiac anatomy (age=17years), using a 3D radial, non-slice-selective, T2-prepared, fat-saturated bSSFP sequence on a 1.5T MRI scanner (MAGNETOM Aera, Siemens, Germany). The acquisition window (~50-55 ms) was placed in mid-diastole and was adapted for different heart rates. Imaging parameters were as follows: TR/TE=3.1/1.56 ms, FOV=200 mm3, voxel size=1 mm3, FA=115degree, and acquisition time=5-6 minutes (~12000 radial lines). Respiratory motion correction and image reconstruction was performed on the scanner as described in [3]. For comparison, conventional non-gated 3D FLASH or navigator-gated 3D bSSFP sequences were also performed. All results were blinded and randomized for image quality assessment by one pediatric cardiologist and one cardiac radiologist using a five-point scale (1=non-diagnostic, 2=poor, 3=adequate, 4=good, 5=excellent). Statistical analysis was performed to compare mean scores. DICOM images were imported to a 3D workstation (Mimics, Materialise, Leuven, Belgium) for 3D postprocessing. The cardiovascular anatomy was first segmented using a combination of automated and manual techniques; and volume rendering was performed to depict the anatomy of interest. Results: The free-breathing self-navigated 3D radial acquisition provided significantly improved image quality and myocardial wall-blood contrast (Figure 1). Mean scores were 4.58 and 2.67 for the 3D radial and FLASH/ bSSFP sequences respectively (p = 0.003). The cardiovascular anatomy was well depicted on all virtual 3D models (Figure 2). Conclusions: 3D virtual models are frequently being created to understand complex anatomy, influence surgical planning, and provide intra-operative guidance for patients with CHD. This novel free-breathing, self-navigated whole heart 3D radial sequence provided excellent image quality as compared to existing routine MR sequences. Furthermore, the (Figure Presented) superb image quality provided using this novel sequence makes it an excellent choice for the creation of 3D models

Anomalous aortic origin of the coronary artery (AAOCA) from the opposite sinus of Valsalva with an interarterial course has become a high-profile lesion as a result of its association with sudden cardiac death in otherwise young and healthy individuals. Despite our incomplete knowledge of its pathophysiology and natural history, surgical intervention is often recommended. Evidence now shows AAOCA to be relatively common, with lower than previously suspected rates of sudden cardiac death. Analysis of this information reveals that AAOCA is not always a surgical disease. Future multi-institutional studies will continue to define those subgroups best served by observation or surgery.

BACKGROUND: Repair of complete atrioventricular canal early in infancy has traditionally carried greater morbidity and mortality than repair performed later. However, an individualized anatomy-based repair may give young infants outcomes that are equivalent to older patients. METHODS: We retrospectively reviewed 139 patients who underwent complete atrioventricular canal repair from January 2005 to December 2012. An individualized approach was used: 2-patch repair was performed in 98 patients for large ventricular septal defects and a modified single-patch ("Australian technique") was used in 41 for "shallow" ventricular septal defects. RESULTS: The average age was 25.5 +/- 3.9 weeks, 50% were boys, and 78% had trisomy 21. Mean follow-up was 5.1 +/- 0.2 years, with 100% completeness of data. There were 3 in-hospital deaths (2.1%) and 1 late death (0.7%). A permanent pacemaker was required in 2 patients (1.4%). The rate for left atrioventricular valve reoperation was 8% at a mean of 211 +/- 238 days after the original repair (range, 6 to 682 days). Compared with patients aged older than 3 months, the 39 patients (28%) who were younger than 3 months had similar perioperative courses and rate of reoperation. Compared with patients with an Australian repair, the 98 patients (71%) with a 2-patch repair were more likely to have trisomy 21 and had slightly increased cardiopulmonary bypass and cross-clamp times but similar outcomes. Multivariate analysis showed postoperative left atrioventricular valve regurgitation greater than 2 and left ventricular outflow tract obstruction were significant risk factors for reoperation on the left atrioventricular valve (both p < 0.05). CONCLUSIONS: Repair of complete atrioventricular canal using an individualized surgical approach yields reoperation and early mortality rates similar for younger infants compared with older infants, obviating the need to delay operation in symptomatic patients.

Given the purported hemodynamic advantages of the right ventricle (RV) to pulmonary artery (PA) conduit, many surgeons have adopted it as their preferred source of pulmonary blood flow during stage I palliation for hypoplastic left heart syndrome. Potential disadvantages of the RV-PA shunt include ventricular dysfunction, pseudoaneurysm formation, arrhythmia, and conduit obstruction, which can lead to a higher rate of unplanned reinterventions. The "dunk" technique was described to reduce the RV incision and proximal conduit obstruction; however, insertion of the ringed graft from the epicardium can be cumbersome and risk RV injury. We introduce a simplified, alternative method of placing the conduit, which we call the periscope technique, whereby the graft is withdrawn from within the RV cavity.

In this case report, we describe the use of the Aquadexâ„¢ system for ultrafiltration therapy in the pediatric cardiac intensive care setting in a patient with fluid overload and acute kidney injury after congenital heart surgery. The patient is an 11-year-old, 25 kg male with complex single ventricle anatomy who underwent a one and a half ventricle repair. The patient experienced multiple organ dysfunction syndrome including acute kidney injury in the early post-operative period secondary to low cardiac output syndrome and tachyarrhythmia. Ultrafiltration using the Aquadexâ„¢ system was utilized to treat fluid overload in the setting of acute kidney injury and hemodynamic instability. Negative fluid balance was safely achieved. It was subsequently possible to wean ventilatory and inotropic support. We conclude that the use of ultrafiltration therapy is feasible in hemodynamically unstable pediatric patients with significant fluid overload in the setting of acute kidney injury following congenital heart surgery.