Computational Fluid Dynamics Turbulence Model and Experimental Study for a Fontan Cavopulmonary Assist Device.

Head-flow HQ curves for a Fontan cavopulmonary assist device (CPAD) were measured using a blood surrogate in a mock circulatory loop and simulated with various computational fluid dynamics (CFD) models. The tests benchmarked the CFD tools for further enhancement of the CPAD design. Recommended Reynolds-Averaged Navier-Stokes (RANS) CFD approaches for the development of conventional ventricular assist devices (VAD) were found to have shortcomings when applied to the Fontan CPAD, which is designed to neutralize off-condition obstruction risks that could contribute to a major adverse event. The no-obstruction condition is achieved with a von Karman pump, utilizing large clearances and small blade heights, which challenge conventional VAD RANS-based CFD hemodynamic simulations. High-fidelity large eddy simulation (LES) is always recommended; however, this may be cost-inhibitive for optimization studies in commercial settings, thus the reliance on RANS models. This study compares head and power predictions of various RANS turbulence models, employing experimental measurements and LES results as a basis for comparison. The models include standard k-ϵ, re-normalization group k-ϵ, realizable k-ϵ, shear stress transport (SST) k-ω, SST with transitional turbulence, and Generalized k-ω. For the pressure head predictions, it was observed that the standard k-ϵ model provided far better agreement with experiment. For the rotor torque, k-ϵ predictions were 30% lower than LES, while the SST and LES torque values were near identical. For the Fontan CPAD, the findings support using LES for the final design simulations, k-ϵ model for head and general flow simulation, and SST for power, shear stress, hemolysis, and thrombogenicity predictions.

Passive performance evaluation and validation of a viscous impeller pump for subpulmonary fontan circulatory support.

Patients with single ventricle defects undergoing the Fontan procedure eventually face Fontan failure. Long-term cavopulmonary assist devices using rotary pump technologies are currently being developed as a subpulmonary power source to prevent and treat Fontan failure. Low hydraulic resistance is a critical safety requirement in the event of pump failure (0 RPM) as a modest 2 mmHg cavopulmonary pressure drop can compromise patient hemodynamics. The goal of this study is therefore to assess the passive performance of a viscous impeller pump (VIP) we are developing for Fontan patients, and validate flow simulations against in-vitro data. Two different blade heights (1.09 mm vs 1.62 mm) and a blank housing model were tested using a mock circulatory loop (MCL) with cardiac output ranging from 3 to 11 L/min. Three-dimensional flow simulations were performed and compared against MCL data. In-silico and MCL results demonstrated a pressure drop of < 2 mmHg at a cardiac output of 7 L/min for both blade heights. There was good agreement between simulation and MCL results for pressure loss (mean difference - 0.23 mmHg 95% CI [0.24-0.71]). Compared to the blank housing model, low wall shear stress area and oscillatory shear index on the pump surface were low, and mean washout times were within 2 s. This study demonstrated the low resistance characteristic of current VIP designs in the failed condition that results in clinically acceptable minimal pressure loss without increased washout time as compared to a blank housing model under normal cardiac output in Fontan patients.

Passive Performance Evaluation and Validation of a Viscous Impeller Pump for Subpulmonary Fontan Circulatory Support.

Patients with single ventricle defects undergoing the Fontan procedure eventually face Fontan failure. Long-term cavopulmonary assist devices using rotary pump technologies are currently being developed as a subpulmonary power source to prevent and treat Fontan failure. Low hydraulic resistance is a critical safety requirement in the event of pump failure (0 RPM) as a modest 2 mmHg cavopulmonary pressure drop can compromise patient hemodynamics. The goal of this study is therefore to assess the passive performance for a viscous impeller pump (VIP) we are developing for Fontan patients, and validate flow simulations against in-vitro data. Two different blade heights (1.09 mm vs 1.62 mm) and a blank housing model were tested using a mock circulatory loop (MCL) with cardiac output ranging from 3 to 11 L/min. Three-dimensional flow simulations were performed and compared against MCL data. In-silico and MCL results demonstrated a clinically insignificant pressure drop of $<$ 2 mmHg at a cardiac output of 7 L/min for both blade heights. There was good agreement between simulation and MCL results for pressure loss (mean difference -0.23 mmHg 95% CI [0.24 -0.71]). Compared to the blank housing model, low wall shear stress area and oscillatory shear index on the pump surface were low, and mean washout times were within 2 seconds. This study demonstrated the low resistance characteristic of current VIP designs in the failed condition that results in clinically acceptable minimal pressure loss with low risk of thrombosis.

Risk Factors for Reoperation After Arterial Switch Operation.

OBJECTIVE: The timing and nature of and risk factors for reoperation after the arterial switch operation in the setting of d-transposition of the great arteries requires further elucidation. METHODS: A total of 403 patients who underwent arterial switch operation from 1986 to 2017 were reviewed. Institutional preference was for pulmonary artery reconstruction using a pantaloon patch of fresh autologous pericardium. The targets for coronary artery reimplantation were identified by intermittent root distension. Multivariable analysis was used to identify risk factors for reoperation. RESULTS: Median follow-up was 8.6 years (interquartile range [IQR]: 2-16.9). Pulmonary arterioplasty was the most common reoperation (n = 11, 2.7%) at 3.3 years (IQR: 1.4-11.4) postoperatively. Subvalvar right ventricular outflow tract reconstruction (RVOTR) was required in nine (2.2%) patients at 2.5 years (IQR: 1.1-5.3) postoperatively. Aortic valve repair or replacement (AVR/r) was required in seven (1.7%) patients at 13.6 years (IQR: 10.0-15.8) postoperatively. Aortic root replacement (ARR) and Coronary Artery Bypass Graft/coronary patch arterioplasty were required in five (1.2%) patients each at 13.6 years (IQR: 11.0-15.3) and 11.3 years (IQR: 2.3-13.6) postoperatively, respectively. Taussig-Bing anomaly was a risk factor for any reoperation (P = .034). Risk factors for specific reoperations included ventricular septal defect for AVR/r (P = .038), Taussig-Bing anomaly for RVOTR (P = .004), and pulmonary artery banding for ARR (P = .028). CONCLUSIONS: Pantaloon patch pulmonary artery reconstruction and intermittent neo-aortic root distension during coronary reimplantation have minimized respective outflow tract reoperations. Certain anatomic subsets carry different risks for late reoperation, and pulmonary artery and/or RVOT reinterventions tend to occur sooner than aortic reinterventions. Special attention to these higher risk subpopulations will be critical to optimizing lifelong outcomes.

Two Decades Using Stentless Porcine Aortic Root in Right Ventricular Outflow Tract Reconstruction.

BACKGROUND: The stentless porcine aortic root prosthesis (SPAR) has been described as a suitable valve for right ventricular outflow tract reconstruction (RVOTR). Indiana University Methodist Hospital in Indianapolis, Indiana began using this valve for RVOTR in 1998. This study reports medium-term to late- term outcomes of the valve in the pulmonary position. METHODS: A retrospective chart review was conducted of patients older than 18 years of age who underwent RVOTR with a SPAR between April 2000 and October 2019. Primary outcomes included survival and freedom from any valvular reintervention. Secondary outcomes included endocarditis and conduit dysfunction detected by routine echocardiography or cardiac magnetic resonance imaging. RESULTS: A total of 135 patients underwent RVOTR with a SPAR at a median age of 32.4 years (range, 18 to 71 years). Of these patients, 129 had previous surgery. Indications included pulmonary insufficiency (90.4%), stenosis (34.8%), endocarditis (7.4%), and carcinoid (4.4%). Median follow-up was 2.97 years (interquartile range, 0.6 to 8.0 years). Overall survival was 93.3%, with 3 perioperative death and 6 late deaths. Endocarditis developed in 4 patients (2.9%), 2 of whom required reoperation. Progressive conduit degradation was evident at 10 years, with 22.2% and 7.7% having moderate stenosis and insufficiency, respectively. Eight (5.9%) reinterventions included 2 surgical replacements, 3 percutaneous replacements, and 3 balloon valvuloplasties at means of 8.5, 7.4, and 2.2 years, respectively. Overall freedom from reintervention at 1, 5, and 10 years was 99.1%, 94.7% and 90.7%, respectively. CONCLUSIONS: In this large, single-institution experience with a long follow-up period, use of the SPAR demonstrated excellent midterm to long-term durability, low rates of endocarditis, and high freedom from reintervention.

Surgical Valvuloplasty Versus Balloon Dilation for Congenital Aortic Stenosis in Pediatric Patients.

BACKGROUND: For children with congenital aortic stenosis (AS) who are candidates for biventricular repair, valvuloplasty can be achieved by surgical aortic valvuloplasty (SAV) or by transcatheter balloon aortic dilation (BAD). We aimed to evaluate the longer term outcomes of SAV versus BAD at our institution. METHODS: We retrospectively reviewed the outcomes of 2 months to 18 years old patients who underwent SAV or BAD at our institution between January 1990 and July 2018. Baseline and follow-up characteristics were assessed by echocardiography. Long-term survival, freedom from reintervention, freedom from aortic valve replacement (AVR), and aortic regurgitation were evaluated. RESULTS: A total of 212 patients met inclusion criteria (SAV = 123; BAD = 89). Age, sex, aortic insufficiency (AI), and aortic valve gradient were similar between the groups. At 10 years, 27.9% (19/68) of SAV patients and 58.3% (28/48) of BAD patients had moderate or worse AI (P = .001), and reintervention occurred in 39.2% (29/74) of SAV patients and 78.6% (44/56) of BAD patients (P < .001). Kaplan-Meier analysis revealed overall survival was 96.8% (119/123) for SAV and 95.5% (85/89) for SAV (P = .87). At 10 years, 35% (23/66) of SAV patients and 54% (23/43) of BAD patients underwent AVR (P = .213). CONCLUSIONS: Surgical aortic valvuloplasty demonstrated greater gradient reduction, less postoperative and long-term AI, and a lower reintervention rate at 10 years than BAD. There was no difference in survival or AVR reintervention rate. Surgical aortic valvuloplasty is a durable and efficacious intervention and should continue to be considered a favorable choice for palliation of valvular AS.

Right Ventricular Outflow Tract Reconstruction in Infant Truncus Arteriosus: A 37-year Experience.

BACKGROUND: Multiple conduits for right ventricular outflow tract reconstruction exist, although the ideal conduit that maximizes outcomes remains controversial. We evaluated long-term outcomes and compared conduits for right ventricular outflow tract reconstruction in children with truncus arteriosus. METHODS: Records of patients who underwent truncus arteriosus repair at our institution between 1981 and 2018 were retrospectively reviewed. Primary outcomes included survival and freedom from catheter reintervention or reoperation. Secondary analyses evaluated the effect of comorbidity, operation era, conduit type, and conduit size. RESULTS: One hundred patients met inclusion criteria. Median follow-up time was 15.6 years (interquartile range, 5.3-22.2). Actuarial survival at 30 days, 5 years, 10 years, and 15 years was 85%, 72%, 72%, and 68%, respectively. Early mortality was associated with concomitant interrupted aortic arch (hazard ratio, 5.4; 95% confidence interval, 1.7-17.4; P = .005). Median time to surgical reoperation was 4.6 years (interquartile range, 2.9-6.8; n = 58). Right ventricle to pulmonary artery continuity was established with an aortic homograft (n = 14), pulmonary homograft (n = 41), or bovine jugular vein conduit (n = 36) in most cases. Multivariate analysis revealed longer freedom from reoperation with the bovine jugular vein conduit compared with the aortic homograft (hazard ratio, 3.1; 95% confidence interval, 1.3-7.7; P = .02) with no difference compared with the pulmonary homograft. Larger conduit size was associated with longer freedom from reoperation (hazard ratio, 0.7; 95% confidence interval, 0.6-0.9; P < .001). CONCLUSIONS: The bovine jugular vein conduit is a favorable conduit for right ventricular outflow tract reconstruction in patients with truncus arteriosus. Concomitant interrupted aortic arch is a risk factor for early mortality.

Bovine jugular vein conduit versus pulmonary homograft in the Ross operation.

OBJECTIVES: The Ross procedure involves using the native pulmonary valve for aortic valve replacement then replacing the pulmonary valve with an allograft or xenograft. We aimed to compare our age-matched experience with the bovine jugular vein conduit and the pulmonary homograft for pulmonary valve replacement during the Ross procedure in children. METHODS: Between 1998 and 2016, 15 patients <18 years of age underwent a Ross procedure using the bovine jugular vein conduit (Ross-Bovine Jugular Vein Conduit) at our institution. These patients were age-matched with 15 patients who had the Ross operation with a standard pulmonary homograft for right ventricular outflow tract reconstruction (Ross-Pulmonary Homograft). Paper and electronic medical records were retrospectively reviewed. RESULTS: The median age of the Ross-Bovine Jugular Vein Conduit and Ross-Pulmonary Homograft patients were 4.8 years (interquartile range 1.1-6.6) and 3.3 years (interquartile 1.2-7.6), respectively (p = 0.6). The median follow-up time for the Ross-Bovine Jugular Vein Conduit and Ross-Pulmonary Homograft groups were 1.7 years (interquartile range 0.5-4.9) and 6.8 years (interquartile range 1.9-13.4), respectively (p = 0.03). Overall, 5-year survival, freedom from redo aortic valve replacement, and freedom from pulmonary valve replacement were similar between groups. CONCLUSION: The bovine jugular vein conduit and pulmonary homograft have favourable mid-term durability when used for right ventricular outflow tract reconstruction for the Ross operation. The bovine jugular vein conduit may be a suitable replacement for appropriately sized patients undergoing a Ross aortic valve replacement, though longer follow-up is needed.

Intermediate Outcomes of Staged Tetralogy of Fallot Repair.

BACKGROUND: The optimal surgical strategy for tetralogy of Fallot (TOF) repair in neonates and young infants requiring early surgical intervention remains controversial. Our surgical center follows the uniform strategy of a staged approach with initial systemic-to-pulmonary artery shunt the majority of time when early surgical intervention is required. We characterized a contemporary cohort of patients with TOF with pulmonary stenosis (PS) undergoing staged repair in order to determine the rate of pulmonary valve-sparing repair (PVSR), growth of the pulmonary valve annulus and pulmonary arteries, postoperative morbidity and mortality, and need for reintervention. METHODS: We retrospectively studied patients with TOF/PS who underwent staged repair from 2000 to 2017. Surgical details, postoperative course, and reinterventions were noted. Echocardiographic measurements and Z-score values of pulmonary valve annulus, main pulmonary artery (MPA), right pulmonary artery (RPA), and left pulmonary artery (LPA) diameters were evaluated. RESULTS: Of the 59 patients with staged TOF/PS, PVSR was performed in 25 (42%). There was a 5% incidence of postoperative arrhythmia. The Z-scores of MPA, RPA, and LPA were significantly higher before complete repair when compared to before palliative shunt. The 5 and 10-year survival rates were both 93%, and the probability of freedom from reoperation at 5 and 10 years was 87% and 82%, respectively. CONCLUSIONS: Staged repair of TOF in young symptomatic infants results in 42% receiving PVSR, pulmonary artery growth, low incidence of postoperative arrhythmia, and relatively low rate of reoperations.

Late manifestation coarctation of the aorta in a premature infant 4-month post-percutaneous device closure of a patent ductus arteriosus.

Patent ductus arteriosus is the most common cardiovascular abnormality in premature infants. With newly available percutaneous devices, centres are reporting high rates of success and favourable safety profiles with percutaneous closure of haemodynamically significant ductus arteriosi in infants under 1000 g. We report the case of a 5-week-old, previous 25-week gestation, 1200-g infant who underwent successful percutaneous closure of a ductus arteriosus with a Medtronic Microvascular Plug but who developed late-term coarctation from the device. This case should prompt practitioners to consider the need and timing of follow-up echocardiograms in this population and sheds light on a newly reported long-term complication of device closure in premature infants.

Cavopulmonary assist: Long-term reversal of the Fontan paradox.

OBJECTIVE: Fontan circulatory inefficiency can be addressed by replacing the missing subpulmonary power source to reverse the Fontan paradox. An implantable cavopulmonary assist device is described that will simultaneously reduce systemic venous pressure and increase pulmonary arterial pressure, improving preload and cardiac output, in a univentricular Fontan circulation on a long-term basis. METHODS: A rotary blood pump that was based on the von Karman viscous pump was designed for implantation into the total cavopulmonary connection (TCPC). It will impart modest pressure energy to augment Fontan flow without risk of obstruction. In the event of rotational failure, it is designed to default to a passive flow diverter. Pressure-flow performance was characterized in vitro in a Fontan mock circulatory loop with blood analog. RESULTS: The pump performed through the fully specified operating range, augmenting flow in all 4 directions of the TCPC. Pressure rise of 6 to 8 mm Hg was readily achieved, ranging to 14 mm Hg at highest speed (5600 rpm). Performance was consistent across a wide range of cardiac outputs. In stalled condition (0 rpm), there was no discernible pressure loss across the TCPC. CONCLUSIONS: A blood pump technology is described that can reverse the Fontan paradox and may permit a surgical strategy of long-term biventricular maintenance of a univentricular Fontan circulation. The technology is intended for Fontan failure in which right-sided circulatory inefficiencies predominate and ventricular systolic function is preserved. It may also apply before clinical Fontan failure as health maintenance to preempt the progression of Fontan disease.

Evaluation and Management of the Child and Adult With Fontan Circulation: A Scientific Statement From the American Heart Association.

It has been 50 years since Francis Fontan pioneered the operation that today bears his name. Initially designed for patients with tricuspid atresia, this procedure is now offered for a vast array of congenital cardiac lesions when a circulation with 2 ventricles cannot be achieved. As a result of technical advances and improvements in patient selection and perioperative management, survival has steadily increased, and it is estimated that patients operated on today may hope for a 30-year survival of >80%. Up to 70 000 patients may be alive worldwide today with Fontan circulation, and this population is expected to double in the next 20 years. In the absence of a subpulmonary ventricle, Fontan circulation is characterized by chronically elevated systemic venous pressures and decreased cardiac output. The addition of this acquired abnormal circulation to innate abnormalities associated with single-ventricle congenital heart disease exposes these patients to a variety of complications. Circulatory failure, ventricular dysfunction, atrioventricular valve regurgitation, arrhythmia, protein-losing enteropathy, and plastic bronchitis are potential complications of the Fontan circulation. Abnormalities in body composition, bone structure, and growth have been detected. Liver fibrosis and renal dysfunction are common and may progress over time. Cognitive, neuropsychological, and behavioral deficits are highly prevalent. As a testimony to the success of the current strategy of care, the proportion of adults with Fontan circulation is increasing. Healthcare providers are ill-prepared to tackle these challenges, as well as specific needs such as contraception and pregnancy in female patients. The role of therapies such as cardiovascular drugs to prevent and treat complications, heart transplantation, and mechanical circulatory support remains undetermined. There is a clear need for consensus on how best to follow up patients with Fontan circulation and to treat their complications. This American Heart Association statement summarizes the current state of knowledge on the Fontan circulation and its consequences. A proposed surveillance testing toolkit provides recommendations for a range of acceptable approaches to follow-up care for the patient with Fontan circulation. Gaps in knowledge and areas for future focus of investigation are highlighted, with the objective of laying the groundwork for creating a normal quality and duration of life for these unique individuals.

Minimization of Surgical Site Infections in Patients With Delayed Sternal Closure After Pediatric Cardiac Surgery.

BACKGROUND: Delayed sternal closure (DSC) following pediatric cardiac surgery is commonly implemented at many centers. Infectious complications occur in 18.7% of these patients based on recent multicenter data. We aimed to describe our experience with DSC, hypothesizing that our practices surrounding the implementation and maintenance of the open sternum during DSC minimize the risk of infectious complications. METHODS: We reviewed patients less than 365 days who underwent DSC between 2012 and 2016 at our institution. Infectious complications as defined by the Society of Thoracic Surgeons Congenital Heart Surgery Database were recorded. Patients with and without infectious complications were compared using Wilcoxon rank sum tests or Fisher exact tests as appropriate. RESULTS: We identified 165 patients less than 365 days old who underwent DSC, 135 (82%) of whom had their skin closed over their open sternum. Median duration of open sternum was 3 days (range: 1-32 days). Infectious complications occurred in 15 (9.1%) patients-13 developed clinical sepsis with positive blood cultures, one patient developed ventilator-associated pneumonia, and one patient developed wound infection (0.6%). No cases of mediastinitis occurred. No statistical differences in characteristics between patients with and without infectious complications could be identified. CONCLUSION: Infectious complications after DSC at our institution were notably less than reported in recent literature, primarily due to minimization of surgical site infections. Practices described in the article, including closing skin over the open sternum whenever possible, could potentially aid other institutions aiming to reduce infectious complications associated with DSC.

Early conversion of classic Fontan conversion may decrease term morbidity: single centre outcomes.

BACKGROUND: The initial classic Fontan utilising a direct right atrial appendage to pulmonary artery anastomosis led to numerous complications. Adults with such complications may benefit from conversion to a total cavo-pulmonary connection, the current standard palliation for children with univentricular hearts. METHODS: A single institution, retrospective chart review was conducted for all Fontan conversion procedures performed from July, 1999 through January, 2017. Variables analysed included age, sex, reason for Fontan conversion, age at Fontan conversion, and early mortality or heart transplant within 1 year after Fontan conversion. RESULTS: A total of 41 Fontan conversion patients were identified. Average age at Fontan conversion was 24.5 ± 9.2 years. Dominant left ventricular physiology was present in 37/41 (90.2%) patients. Right-sided heart failure occurred in 39/41 (95.1%) patients and right atrial dilation was present in 33/41 (80.5%) patients. The most common causes for Fontan conversion included atrial arrhythmia in 37/41 (90.2%), NYHA class II HF or greater in 31/41 (75.6%), ventricular dysfunction in 23/41 (56.1%), and cirrhosis or fibrosis in 7/41 (17.1%) patients. Median post-surgical follow-up was 6.2 ± 4.9 years. Survival rates at 30 days, 1 year, and greater than 1-year post-Fontan conversion were 95.1, 92.7, and 87.8%, respectively. Two patients underwent heart transplant: the first within 1 year of Fontan conversion for heart failure and the second at 5.3 years for liver failure. CONCLUSIONS: Fontan conversion should be considered early when atrial arrhythmias become common rather than waiting for severe heart failure to ensue, and Fontan conversion can be accomplished with an acceptable risk profile.

Rastelli Operation for D-Transposition of the Great Arteries, Ventricular Septal Defect, and Pulmonary Stenosis.

OBJECTIVES: Our preferred approach for the surgical treatment of patients with D-transposition of the great arteries, ventricular septal defect, and pulmonary stenosis has been the Rastelli operation. We herein evaluate our 30-year experience with this procedure. METHODS: Clinical records for patients who underwent the Rastelli operation between 1988 and 2017 at our institution were retrospectively reviewed. Primary outcomes included freedom from death or cardiac transplantation and freedom from conduit reintervention. RESULTS: Forty-seven patients met inclusion criteria. Mean follow-up was 11.7 ± 6.8 years. Forty-three (91.5%) patients received a palliative systemic-to-pulmonary artery shunt and/or atrial septostomy prior to the Rastelli procedure. Five (10.6%) patients required ventricular septal defect enlargement at the time of the Rastelli procedure. The overall mean right ventricle-to-pulmonary artery conduit size was 17.0 mm. Mortalities included one early and three late deaths. Freedom from death or cardiac transplantation was 93% and 84% at 5 and 25 years, respectively. Seven patients required pacemaker placement, two immediately postoperatively and five late. Freedom from conduit replacement was 85% and 25% at 5 and 15 years, respectively. Seven (14.9%) patients required a second conduit intervention. Forty-one (87.2%) patients were New York Heart Association class I or II at the most recent follow-up. CONCLUSIONS: The Rastelli operation for D-transposition of the great arteries, ventricular septal defect, and pulmonary stenosis offers excellent mid- to long-term survival. The need for conduit replacement remains the most common indication for reintervention, and further study of the optimal choice of conduit will be useful.

Bovine Jugular Vein Conduit: A Mid- to Long-Term Institutional Review.

BACKGROUND: Since 1999, we have used the bovine jugular vein conduit for right ventricular outflow tract reconstruction in infants and children. Herein, we review their mid- to long-term outcomes. METHODS: Between 1999 and 2016, 315 bovine jugular vein conduits were implanted in 276 patients. Patients were grouped by age at bovine jugular vein conduit implant: group 1: 0 to 1 years (N = 65), group 2: one to ten years (N = 132), and group 3: older than ten years (N = 118). For survival and hemodynamic analysis, additional group stratification was done based on conduit size. Group small: 12 and 14 mm (N = 75), group medium: 16 and 18 mm (N = 84), and group large: 20 and 22 mm (N = 156). RESULTS: Mean follow-up for groups 1, 2, and 3 was 4.0, 4.9, and 5.9 years, respectively. Early mortality was 9%, 0%, and 1% for groups 1, 2, and 3, respectively ( P < .001). Late mortality was 5%, 2%, and 2% for groups 1, 2, and 3, respectively ( P = .337). Group 1 had the lowest ten-year freedom from conduit failure at 13%, versus 53% and 69% for groups 2 and 3, respectively ( P < .001). A total of 21 (6.6%) patients developed endocarditis, 11 (3.5%) patients required reoperation, and 10 (3.2%) patients required antibiotic therapy alone. CONCLUSIONS: The bovine jugular vein conduit is a useful option for right ventricular outflow tract reconstruction given its easy implantability and acceptable midterm durability.

Congenital aortic paravalvular tunnel masquerading as a recurrent ventricular septal defect.

A 4-year-old female underwent surgical repair of an unusual variation of an aorto-left ventricular tunnel (ALVT). Serial echocardiograms had demonstrated previous spontaneous closure of a perimembranous ventricular septal defect (VSD). The patient presented with concern for residual VSD which was later demonstrated to be an eccentric jet through an ALVT. This case emphasizes early and accurate diagnosis for ALVTs and how they can be misdiagnosed as VSDs.

Multiblock High Order Large Eddy Simulation of Powered Fontan Hemodynamics: Towards Computational Surgery.

Children born with only one functional ventricle must typically undergo a series of three surgeries to obtain the so-called Fontan circulation in which the blood coming from the body passively flows from the Vena Cavae (VCs) to the Pulmonary Arteries (PAs) through the Total Cavopulmonary Connection (TCPC). The circulation is inherently inefficient due to the lack of a subpulmonary ventricle. Survivors face the risk of circulatory sequelae and eventual failure for the duration of their lives. Current efforts are focused on improving the outcomes of Fontan palliation, either passively by optimizing the TCPC, or actively by using mechanical support. We are working on a chronic implant that would be placed at the junction of the TCPC, and would provide the necessary pressure augmentation to re-establish a circulation that recapitulates a normal two-ventricle circulation. This implant is based on the Von Karman viscous pump and consists of a vaned impeller that rotates inside the TCPC. To evaluate the performance of such a device, and to study the flow features induced by the presence of the pump, Computational Fluid Dynamics (CFD) is used. CFD has become an important tool to understand hemodynamics owing to the possibility of simulating quickly a large number of designs and flow conditions without any harm for patients. The transitional and unsteady nature of the flow can make accurate simulations challenging. We developed and in-house high order Large Eddy Simulation (LES) solver coupled to a recent Immersed Boundary Method (IBM) to handle complex geometries. Multiblock capability is added to the solver to allow for efficient simulations of complex patient specific geometries. Blood simulations are performed in a complex patient specific TCPC geometry. In this study, simulations without mechanical assist are performed, as well as after virtual implantation of the temporary and chronic implants being developed. Instantaneous flow structures, hepatic factor distribution, and statistical data are presented for all three cases.