Tetralogy of Fallot complicated by multiple cerebral abscesses in a child: a case report.

INTRODUCTION: Brain abscesses are rare but potentially fatal condition and can be associated with cyanotic congenital heart disease of which 5-18.7% of these patients that develop cerebral abscess commonly have tetralogy of Fallot (TOF). CASE PRESENTATION: We report a case of 3-year-old Muganda male that presented with convulsions, cyanosis and difficulty in breathing. The patient had a combination intervention of medical treatment and surgical drainage of the abscess. Post-operative Computerized tomography scan images and pre-operative brain Computerized tomography scans were compared. The multiple rings enhancing lesions were reduced in number and sizes. The largest measured ring was 44 × 22.5×16mm compared to the previous; 42 × 41×36mm. The mass effect had reduced from 16 mm to 7.5 mm. The periventricular hypodensities persisted. Findings showed radiological improvement with residual abscesses, subacute subdural hematoma and pneumocranium. The patient was treated with intravenous ceftriaxone 1 g OD for six weeks and he showed marked improvement and was discharged home after 3 months. CONCLUSION: A comprehensive strategy involving medications, surgical drainage, and early neurosurgical consultation is vital in treating brain abscesses in uncorrected TOF. Early identification of the pathogen, appropriate antibiotic therapy, and vigilant follow-up through clinical assessments and imaging are crucial, potentially spanning a 4-8-week treatment.

Enhanced echocardiographic assessment of intracardiac flow in congenital heart disease.

BACKGROUND: 4D flow magnetic resonance imaging (4D flow MRI) can assess and measure the complex flow patterns of the right ventricle (RV) in congenital heart diseases, but its limited availability makes the broad application of intracardiac flow assessment challenging. Color Doppler imaging velocity reconstruction from conventional echocardiography is an emerging alternative, but its validity against 4D flow MRI needs to be established. OBJECTIVE: To compare intracardiac flow parameters measured by color Doppler velocity reconstruction (DoVeR) against parameters measured from 4D flow MRI. METHODS: We analyzed 20 subjects, including 7 normal RVs and 13 abnormal RVs (10 with repaired Tetralogy of Fallot, and 3 with atrial-level shunts). Intracardiac flow parameters such as relative pressure difference, vortex strength, total kinetic energy, and viscous energy loss were quantified using DoVeR and 4D flow MRI. The agreement between the two methods was determined by comparing the spatial fields and quantifying the cross-correlation and normalized difference between time-series measurements. RESULTS: The hemodynamic parameters obtained from DoVeR and 4D flow MRI showed similar flow characteristics and spatial distributions. The time evolutions of the parameters were also in good agreement between the two methods. The median correlation coefficient between the time-series of any parameter was between 0.87 and 0.92, and the median L2-norm deviation was between 10% to 14%. CONCLUSIONS: Our study shows that DoVeR is a reliable alternative to 4D flow MRI for quantifying intracardiac hemodynamic parameters in the RV.

Morphometrics predicts the differential regurgitant fraction in bilateral pulmonary arteries of patients with repaired tetralogy of fallot.

In patients with repaired tetralogy of Fallot (rTOF), the regurgitant fraction (RF) in left pulmonary artery (LPA) and right pulmonary artery (RPA) is usually unequal. The morphometrics may play a crucial role in this RF discrepancy. Cardiovascular MR of 79 rTOF patients and 20 healthy controls were retrospectively enrolled. Forty-four from the 79 patients were matched in age, sex and body surface area to the 20 controls and were investigated for: (1) phase-contrast flow of main pulmonary artery (MPA), LPA, and RPA; (2) vascular angles: the angles between the thoracic anterior-posterior line (TAPL) with MPA (θM-AP), MPA with RPA (θM-R), and MPA with LPA (θM-L); (3) cardiac angle, the angle between TAPL and the interventricular septum; (4) area ratio of bilateral lung and hemithorax regions. Compared with the 20 controls, the 44 rTOF patients exhibited wider θM-AP, sharper θM-L angle, and a smaller θM-L/θM-R ratio. In the 79 rTOF patients, LPA showed lower forward, backward, and net flow, and greater RF as compared with RPA. Multivariate analysis showed that the RF of LPA was negatively associated with the θM-L/θM-R ratio and the age at surgery (R2 = 0.255). Conversely, the RF of RPA was negatively associated with the left lung/left hemithorax area ratio and cross-sectional area (CSA) of LPA, and positively associated with CSA of RPA and MPA (R2 = 0.366). In rTOF patients, the RF of LPA is more severe than that of RPA, which may be related to the vascular morphometrics. Different morphometric parameters are independently associated with the RF of LPA or RPA, which may offer potential insights for surgical strategies.

Right Ventricular and Outflow Tract Functional Characteristics After Repair of Tetralogy of Fallot with Major Aortopulmonary Collaterals.

This study describes right ventricle (RV) characteristics and right ventricle to pulmonary artery (RV-PA) conduit function pre- and post-repair in patients with tetraology of Fallot with major aortopulmonary collaterals (TOF/MAPCAs). We reviewed patients who underwent single-stage, complete unifocalization, and repair of TOF/MAPCAs between 2006 and 2019 with available pre- and early postoperative echocardiograms. For a subset of patients, 6-12 month follow-up echocardiogram was available. RV and left ventricle (LV) characteristics and RV-PA conduit function were reviewed. Wilcoxon signed rank test and McNemar's test were used. 170 patients were reviewed, 46 had follow-up echocardiograms. Tricuspid valve annular plane systolic excursion (TAPSE) Z-scores were reduced from pre- (Z-score 0.01) to post-repair (Z-score -4.5, p < 0.001), improved but remained abnormal at follow-up (Z-score -4.0, p < 0.001). RV fractional area change (FAC) and LV ejection fraction were not significantly different before and after surgery. Conduit regurgitation was moderate or greater in 11% at discharge, increased to 65% at follow-up. RV-PA conduit failure (severe pulmonary stenosis or severe pulmonary regurgitation) was noted in 61, and 63% had dilated RV (diastolic RV area Z-score > 2) at follow-up. RV dilation correlated with the severe conduit regurgitation (p = 0.018). Longitudinal RV function was reduced after complete repair of TOF/MAPCAs, with decreased TAPSE and preserved FAC and LV ejection fraction. TAPSE improved but did not normalize at follow-up. Severe RV-PA conduit dysfunction was observed prior to discharge in 11% of patients and in 61% at follow-up. RV dilation was common at follow-up, especially in the presence of severe conduit regurgitation.

Transcatheter pulmonary valve replacement in surgically-created double-barrel right ventricular outflow tracts: A single center case-series.

This manuscript describes the feasibility and approach to the assessment and performance of transcatheter pulmonary valve replacement (tPVR) in patients with surgically-created "double-barrel" right ventricular outflow tracts (RVOT). Patients with tetralogy of Fallot may have coronary anomalies which prohibit the performance of traditional tetralogy of Fallot repair. In certain cases, this may necessitate the placement of a right ventricle to pulmonary artery conduit in addition to the native RVOT, which is left in situ, creating so-called "double-barrel" RVOTs. When these patients develop RVOT dysfunction later in life, they would typically be referred for reoperation due to concerns for risk of coronary compression associated with a transcatheter approach. However, whether a transcatheter approach with valve replacement in the native RVOT is feasible or safe is unknown. This was a retrospective review of patients with a surgically created "double-barrel" RVOTs who underwent cardiac catheterization for assessment of tPVR at Boston Children's Hospital. From July 2012 to July 2022, there were four patients with "double-barrel" RVOTs who underwent assessment for tPVR. The age at catheterization ranged between 22 and 39 years. In three out of four patients, coronary compression testing was negative. These three patients had successful tPVR in the native RVOT. At follow up, all three patients were free of greater than mild regurgitation by echocardiogram and had a maximum instantaneous gradient across the RVOT ranging between 20 and 33 mmHg. Performance of tPVR in patients with surgically created "double-barrel" RVOTs is feasible. The safety of this procedure depends crucially on coronary artery assessment at all stages.

Predictive value of Cardiac Magnetic Resonance: new and old parameters in the natural history of repaired Tetralogy of Fallot.

BACKGROUND: Patients with repaired Tetralogy of Fallot (rTOF) often develop pulmonary regurgitation (PR) and right ventricle (RV) dysfunction, experiencing increased mortality and morbidity rates in adulthood. Pulmonary valve replacement (PVR) timing to address PR is controversial. Cardiac Magnetic Resonance (CMR) is the gold standard for morpho-functional evaluation of complex cardiopathies. This study aims to identify CMR parameters predictive of adverse outcomes to help defining the best therapeutic management of rTOF patients. METHODS: 130 rTOF patients who underwent CMR (2006-2019) were enrolled in this retrospective single-center study. CMR, clinical, ECG and exercise data were analyzed. Univariate and multivariate analyses identified clinical and CMR parameters predictive of adverse outcomes both individually (e.g., death, arrhythmias, heart failure (HF), pharmacological therapy, QRS ≥ 160ms) and as composite outcome. RESULTS: Univariate analysis confirmed RV volumes and RV ejection fraction corrected for PR as adverse outcome predictors and identified interesting correlations: pulmonary artery bifurcation geometry and abnormal interventricular septum (IVS) motion with arrhythmias (p < .001; p = .037), HF (p = .049; p = .005), composite outcome (p = .039; p = .009); right atrium (RA) dimensions with the composite outcome and the outcomes individually (p < .001). The best predictive models by multivariate analysis included sex (male), RV and RA dilation for QRS ≥ 160ms, time form repair to CMR, age at TOF repair and IVS fibrosis for pharmacological therapy. CONCLUSIONS: Besides RV volumes, new adverse prognostic factors could guide rTOF therapeutic management: pulmonary arteries morphology, abnormal IVS motion, RV dysfunction, RA dilation. Perspective multicentric evaluation is needed to specify their effective role.

Hemodynamic-based virtual surgery design of double-patch repair for pulmonary arterioplasty in tetralogy of Fallot.

BACKGROUND AND OBJECTIVE: Surgical correction of pulmonary artery stenosis (PAS) is essential to the prognosis of patients with tetralogy of Fallot (TOF). The double-patch method of pulmonary arterioplasty is usually applied in case of multiple stenosis in TOF patients' pulmonary artery (PA) and when PAS cannot be relieved by the single-patch method. The surgical planning for the double-patch design remains challenging. The purpose of this study is to investigate the double-patch design with different angulations between the left pulmonary artery (LPA) and the right pulmonary artery (RPA), and to understand postoperative hemodynamic alterations by the application of computer-aided design (CAD) and computational fluid dynamics (CFD) techniques. METHODS: The three-dimensional model of the PA was reconstructed based on preoperative computed tomography imaging data obtained from the patient with TOF. Three postoperative models with different designs of double-patch were created by "virtual surgery" using the CAD technique. Double-Patch 120 Model was created with double patches implanted in the main pulmonary artery (MPA) and the PA bifurcation and without changing the spatial position of PA. The angulation between the LPA and the RPA was defined as θ, which equaled to 120° in Pre-Operative Model and Double-Patch 120 Model. Based on Double-Patch 120 Model, Double-Patch 110 Model and Double-Patch 130 Model were generated with θ equaled to 110° and 130°, respectively. Combined with CFD, the differences of velocity streamlines, wall shear stress (WSS), flow distribution ratio (FDR), and energy loss (EL) were compared to analyze postoperative pulmonary flow characteristics. RESULTS: The values of velocity and WSS decreased significantly after virtual surgery. Obvious vortices and swirling flows were observed downstream of the stenosis of RPA and LPA in Pre-Operative Model, while fewer vortices developed along the anterior wall of the expanded lumens of RPA, especially in Double-Patch 110 Model. With the relief of PAS, two relatively higher WSS regions were observed at the posterior walls of RPA and LPA. The maximum WSS values in these regions of Double-Patch 110 Model were lower than those in Double-Patch 120 Model and Double-Patch 130 Model. Furthermore, the FDRs were elevated and the ELs were greatly reduced. It was found that Double-Patch 110 Model with the angulation between the LPA and the RPA equaled to 110° showed relatively better properties of hemodynamics than other models. CONCLUSIONS: The angulation between the LPA and the RPA is an important factor that should be integrated in the double-patch design for TOF repair. Virtual surgery based on patient-specific vascular model and computational hemodynamics can be used to provide assistance for individualized surgical planning of double-patch arterioplasty.

How to assess and treat right ventricular electromechanical dyssynchrony in post-repair tetralogy of Fallot: insights from imaging, invasive studies, and computational modelling.

BACKGROUND AND AIMS: Right bundle branch block (RBBB) and resulting right ventricular (RV) electromechanical discoordination are thought to play a role in the disease process of subpulmonary RV dysfunction that frequently occur post-repair tetralogy of Fallot (ToF). We sought to describe this disease entity, the role of pulmonary re-valvulation, and the potential added value of RV cardiac resynchronization therapy (RV-CRT). METHODS: Two patients with repaired ToF, complete RBBB, pulmonary regurgitation, and significantly decreased RV function underwent echocardiography, cardiac magnetic resonance, and an invasive study to evaluate the potential for RV-CRT as part of the management strategy. The data were used to personalize the CircAdapt model of the human heart and circulation. Resulting Digital Twins were analysed to quantify the relative effects of RV pressure and volume overload and to predict the effect of RV-CRT. RESULTS: Echocardiography showed components of a classic RV dyssynchrony pattern which could be reversed by RV-CRT during invasive study and resulted in acute improvement in RV systolic function. The Digital Twins confirmed a contribution of electromechanical RV dyssynchrony to RV dysfunction and suggested improvement of RV contraction efficiency after RV-CRT. The one patient who underwent successful permanent RV-CRT as part of the pulmonary re-valvulation procedure carried improvements that were in line with the predictions based on his Digital Twin. CONCLUSION: An integrative diagnostic approach to RV dysfunction, including the construction of Digital Twins may help to identify candidates for RV-CRT as part of the lifetime management of ToF and similar congenital heart lesions.

Adverse remodelling in tetralogy of Fallot: From risk factors to imaging analysis and future perspectives.

Although contemporary outcomes of initial surgical repair of tetralogy of Fallot (TOF) are excellent, the survival of adult patients remains significantly lower than that of the normal population due to the high incidence of heart failure, ventricular arrhythmias, and sudden cardiac death. The underlying mechanisms are only partially understood but involve an adverse biventricular response, so-called remodelling, to key stressors such as right ventricular (RV) pressure-and/or volume-overload, myocardial fibrosis, and electro-mechanical dyssynchrony. In this review, we explore risk factors and mechanisms of biventricular remodelling, from histological to electro-mechanical aspects, and the role of imaging in their assessment. We discuss unsolved challenges and future directions to better understand and treat the long-term sequelae of this complex congenital heart disease.

Atrioventricular Septal Defect With Tetralogy of Fallot and Exclusive Shunting at the Ventricular Level.

Atrioventricular septal defect (AVSD) with shunting restricted to the ventricular level is a rare form of AVSD. To our knowledge, this shunting pattern has not been reported in AVSD with tetralogy of Fallot. We report a child with this unusual combination who underwent a successful single-stage repair at two years of age.

Prognostic value of left atrial strain in patients with tetralogy of fallot.

To demonstrate prognostic utility of left atrial strain (LAS) in adult patients with repaired Tetralogy of Fallot (rTOF). Adults patients with rTOF were prospectively enrolled in this study between years 2011 and 2015. Left atrium (LA) phasic functions were assessed using 2D speckle tracking echocardiography. Association of LA strain (LAS) with primary (any cardiovascular event) and secondary (death, heart failure or arrhythmia) composite endpoints was assessed using Cox regression analysis. Hundred-and-twelve rTOF patients, in whom LAS was feasible and were in sinus rhythm, were included in the final analysis (age 33 ± 10 years, 68[61%] male). Median duration of follow-up was 8.6 [4.2-9.7] years in the study group. Primary composite endpoint was reached in 48 patients (mean event-free survival time: 7.2 [6.6-7.9] years), and secondary composite endpoint was reached in 22 patients (mean event-free survival time: 8.7 [8.1-9.2] years). LA reservoir strain (LAS-r) was defined as tertile groups (1st tertile < 33%, 2nd tertile = 33-44%, 3rd tertile > 44%). Decreasing tertiles of LAS-r was associated with primary and secondary composite endpoints in Kaplan-Meier analysis (p = 0.02 and 0.002, respectively). In univariable Cox-regression, both decreasing LAS-r and LAS-r tertiles were associated with primary and secondary composite endpoints. Adjusted by initial repair age and NT-proBNP quartiles, increased LAS-r was associated with significantly decreased occurrence of experiencing any events (HR = 0.97, CI 0.93-0.99, p < 0.001). Decreasing LAS-r was still associated with primary endpoint when adjusted by left atrium volume index (LAVImax) (HR = 0.96, CI 0.92-0.99, p = 0.01), left ventricle global longitudinal strain (HR = 0.96, CI 0.93-0.99, p < 0.001) or right ventricle free wall longitudinal strain (HR = 0.96, CI 0.93-0.99, p = 0.03). Assessment of LA mechanics with the use of STE has incremental utility in determination of mortality and morbidity in rTOF, and may be implemented in clinical practice.

Pulmonary Valve Replacement in Tetralogy of Fallot: Procedural Volume and Durability of Bioprosthetic Pulmonary Valves.

BACKGROUND: Robust data on changes in pulmonary valve replacement (PVR) procedural volume and predictors of bioprosthetic pulmonary valve (BPV) durability in patients with tetralogy of Fallot (TOF) are scarce. OBJECTIVES: This study sought to assess temporal trends in PVR procedural volume and BPV durability in a nationwide, retrospective TOF cohort. METHODS: Data were obtained from patient records. Robust linear regression was used to assess temporal trends in PVR procedural volume. Piecewise exponential additive mixed models were used to estimate BPV durability, defined as the time from implantation to redo PVR with death as a competing risk, and to assess risk factors for reduced durability. RESULTS: In total, 546 PVR were performed in 384 patients from 1976 to 2021. The annual number of PVR increased from 0.4 to 6.0 per million population (P < 0.001). In the last decade, the transcatheter PVR volume increased by 20% annually (P < 0.001), whereas the surgical PVR volume did not change significantly. The median BPV durability was 17 years (Q1: 10-Q3: 10 years-not applicable). There was no significant difference in the durability of different BPV after adjustment for confounders. Age at PVR (HR: 0.78 per 10 years from <1 year; 95% CI: 0.63-0.96; P = 0.02) and true inner valve diameter (9-17 mm vs 18-22 mm HR: 0.40; 95% CI: 0.22-0.73; P = 0.003 and 18-22 mm vs 23-30 mm HR: 0.59; 95% CI: 0.25-1.39; P = 0.23) were associated with reduced BPV durability in multivariate models. CONCLUSIONS: The PVR procedural volume has increased over time, with a greater increment in transcatheter than surgical PVR during the last decade. Younger patient age at PVR and a smaller true inner valve diameter predicted reduced BPV durability.

Application of Foley balloon catheter in palliative surgery for pulmonary atresia with an intact ventricular septem, with additional cases of pulmonary atresia with ventricular septal defect and tetralogy of Fallot.

BACKGROUND: Pulmonary atresia and tetralogy of Fallot can require palliative surgery in the neonatal period due to severe hypoxia; however, limitations of established techniques include high failure rate and need for cardiopulmonary bypass. Herein, right ventricular outflow tract reconstruction on a beating heart using a Foley balloon catheter is described. METHODS: A retrospective review of patients who underwent right ventricular outflow tract reconstruction on a beating heart using a Foley balloon catheter at our institution between September 2018 and March 2022 was completed. During the procedure, a Foley balloon catheter was used to occlude the blood from the right ventricular inflow tract. RESULTS: Eight patients with pulmonary atresia and intact ventricular septum underwent an off-pump right ventricular outflow tract reconstruction. One patient with pulmonary atresia and ventricular septal defect, and two patients with tetralogy of Fallot underwent an on-pump right ventricular outflow tract reconstruction on a beating heart. The procedures were successful in all patients. Patent ductus arteriosus ligation without modified Blalock-Taussig shunt placement was performed in three patients with pulmonary atresia with intact ventricular septum and two patients with tetralogy of Fallot, ductus arteriosus was left open in four patients with pulmonary atresia with intact ventricular septum. All patients remained clinically well without serious complications. CONCLUSIONS: Right ventricular outflow tract reconstruction on a beating heart using a Foley balloon catheter for pulmonary atresia and tetralogy of Fallot is a feasible alternative to catheter-based interventions or traditional surgical treatment, especially in patients with muscular infundibular stenosis or hypoplastic pulmonary annulus. Further studies with more cases are needed to verify feasibility and superiority of this approach.

Systematic Analysis of PTFE Monocusp Leaflet Design in a Patient-Based 3D in-Vitro Model of Tetralogy of Fallot.

PURPOSE: Pulmonary valve (PV) monocusp reconstruction in transannular patch (TAP) right ventricular outflow tract (RVOT) repair for Tetralogy of Fallot has variable clinical outcomes across different surgical approaches. The study purpose was to systematically evaluate how monocusp leaflet design parameters affect valve function in-vitro. METHODS: A 3D-printed, disease-specific RVOT model was tested under three infant physiological conditions. Monocusps were sewn into models with the native main pulmonary artery (MPA) forming backwalls that constituted 40% and 50% of the reconstructed circumference for z-score zero PV annulus and MPA diameters (native PV z-score - 3.52 and - 2.99 for BSA 0.32m2). Various leaflet free edge lengths (FEL) (relative to backwall), positions (relative to PV STJ), and scallop depths were investigated across both models. Pressure gradient, regurgitation, and coaptation were analyzed with descriptive statistics and regression models. RESULTS: Increasing FEL beyond 100% of the MPA backwall decreased gradient but mildly increased regurgitation to a peak of 25%. Positioning the free edge 2 mm past the STJ mildly increased gradient for each FEL without significantly changing regurgitation compared to STJ placement. Scalloping leaflets trivially affected performance. Pre-folding leaflets improved mobility and slightly reduced gradient. CONCLUSIONS: Balancing gradient, regurgitation, and oversizing for growth, a set of leaflet designs have been selected for pre-clinical evaluation. Designs with leaflet widths 140-160% in the 40% backwall model (110-120% in the 50% backwall), positioned at or 2 mm past the STJ, demonstrated the best results. The next stage of ex-vivo testing will additionally consider native RVOT distensibility, native leaflet interactions, and TAP characteristics.