Surgical Modulation of Pulmonary Artery Shear Stress: A Patient-Specific CFD Analysis of the Norwood Procedure.

PURPOSR: This study created 3D CFD models of the Norwood procedure for hypoplastic left heart syndrome (HLHS) using standard angiography and echocardiogram data to investigate the impact of shunt characteristics on pulmonary artery (PA) hemodynamics. Leveraging routine clinical data offers advantages such as availability and cost-effectiveness without subjecting patients to additional invasive procedures. METHODS: Patient-specific geometries of the intrathoracic arteries of two Norwood patients were generated from biplane cineangiograms. "Virtual surgery" was then performed to simulate the hemodynamics of alternative PA shunt configurations, including shunt type (modified Blalock-Thomas-Taussig shunt (mBTTS) vs. right ventricle-to-pulmonary artery shunt (RVPAS)), shunt diameter, and pulmonary artery anastomosis angle. Left-right pulmonary flow differential, Qp/Qs, time-averaged wall shear stress (TAWSS), and oscillatory shear index (OSI) were evaluated. RESULTS: There was strong agreement between clinically measured data and CFD model output throughout the patient-specific models. Geometries with a RVPAS tended toward more balanced left-right pulmonary flow, lower Qp/Qs, and greater TAWSS and OSI than models with a mBTTS. For both shunt types, larger shunts resulted in a higher Qp/Qs and higher TAWSS, with minimal effect on OSI. Low TAWSS areas correlated with regions of low flow and changing the PA-shunt anastomosis angle to face toward low TAWSS regions increased TAWSS. CONCLUSION: Excellent correlation between clinically measured and CFD model data shows that 3D CFD models of HLHS Norwood can be developed using standard angiography and echocardiographic data. The CFD analysis also revealed consistent changes in PA TAWSS, flow differential, and OSI as a function of shunt characteristics.

Population Pharmacokinetics of Caffeine in Neonates with Congenital Heart Disease and Associations with Acute Kidney Injury.

Cardiac surgery-associated acute kidney injury (CS-AKI) occurs in approximately 65% of neonates undergoing cardiac surgery on cardiopulmonary bypass and contributes to morbidity and mortality. Caffeine may reduce CS-AKI by counteracting adenosine receptor upregulation after bypass, but pharmacokinetics (PK) in this population are unknown. The goal of our analysis is to address knowledge gaps in age-, disease-, and bypass-related effects on caffeine disposition and explore preliminary associations between caffeine exposure and CS-AKI using population PK modeling techniques and an opportunistic, electronic health record-integrated trial design. We prospectively enrolled neonates receiving preoperative caffeine per standard of care and collected PK samples. We retrospectively identified neonates without caffeine exposure undergoing surgery on bypass as a control cohort. We followed US Food and Drug Administration guidance for population PK model development using NONMEM. Effects of clinical covariates on PK parameters were evaluated. We simulated perioperative exposures and used multivariable logistic regression to evaluate the association between caffeine exposure and CS-AKI. Twenty-seven neonates were included in model development. A 1-compartment model with bypass time as a covariate on clearance and volume of distribution best fit the data. Twenty-three neonates with caffeine exposure and 109 controls were included in the exposure-response analysis. Over half of neonates developed CS-AKI. On multivariable analysis, there were no significant differences between CS-AKI with and without caffeine exposure. Neonates with single-ventricle heart disease without CS-AKI had consistently higher simulated caffeine exposures. Our results highlight areas for further study to better understand disease- and bypass-specific effects on drug disposition and identify populations where caffeine may be beneficial.

Hybrid approach to pulmonary vein stenting after Fontan palliation.

Pulmonary vein stenosis is poorly tolerated in patients who have undergone Fontan palliation and typically requires surgical or transcatheter intervention. Percutaneous transcatheter approaches to intervention can be technically difficult due to challenging anatomy. A hybrid per-atrial transcatheter approach for stenting pulmonary veins provides a direct approach to the pulmonary veins and has the potential to improve safety and efficacy of this complex intervention. We describe our experience with hybrid per-atrial pulmonary vein stenting in three patients with pulmonary vein stenosis following Fontan palliation.

Update on Transcatheter Device Closure of Congenital Septal Defects.

PURPOSE OF REVIEW: The goal of this paper is to review currently available devices for closure of atrial septal defects (ASDs) and ventricular septal defects (VSDs). RECENT FINDINGS: Favorable results from the ASSURED trial resulted in FDA approval for the most recently developed device for transcatheter ASD closure in the United States. Further studies are required to assist in the development or approval of safe devices for transcatheter perimembranous VSD closure in pediatric patients. Device closure is the less invasive and preferred management option for many ASDs, with multiple studies demonstrating lower complication rates, shorter hospital stays, and lower mortality than surgical repair. Complex ASDs that make device closure more difficult include large defects, rim deficiencies, fenestrated defects, multiple defects, and the presence of pulmonary arterial hypertension. Device closure has also become an accepted alternative to surgery for some types of ventricular septal defects VSDs, though challenges and limitations remain. Future innovations including novel devices and techniques are needed to further expand on the types of defects that can be safely closed via transcatheter approach.

Association of Urine Biomarkers With Acute Kidney Injury and Fluid Overload in Infants After Cardiac Surgery: A Single Center Ancillary Cohort of the Steroids to Reduce Systemic Inflammation After Infant Heart Surgery Trial.

To examine the association between three perioperative urine biomarker concentrations (urine cystatin C [uCysC], urine neutrophil gelatinase-associated lipocalin [uNGAL], and urine kidney injury molecule 1 [uKIM-1]), and cardiac surgery-associated acute kidney injury (CS-AKI) and fluid overload (FO) in infants with congenital heart disease undergoing surgery on cardiopulmonary bypass. To explore how urine biomarkers are associated with distinct CS-AKI phenotypes based on FO status. DESIGN: Ancillary prospective cohort study. SETTING: Single U.S. pediatric cardiac ICU. PATIENTS: Infants less than 1 year old enrolled in the Steroids to Reduce Systemic Inflammation after Infant Heart Surgery trial (NCT03229538) who underwent heart surgery from June 2019 to May 2020 and opted into biomarker collection at a single center. Infants with preoperative CS-AKI were excluded. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Forty infants met inclusion criteria. Median (interquartile) age at surgery was 103 days (5.5-161 d). Modified Kidney Disease Improving Global Outcomes-defined CS-AKI was diagnosed in 22 (55%) infants and 21 (53%) developed FO. UCysC and uNGAL peaked in the early postoperative period and uKIM-1 peaked later. In unadjusted analysis, bypass time was longer, and Vasoactive-Inotropic Score at 24 hours was higher in infants with CS-AKI. On multivariable analysis, higher uCysC (odds ratio [OR], 1.023; 95% CI, 1.004-1.042) and uNGAL (OR, 1.019; 95% CI, 1.004-1.035) at 0-8 hours post-bypass were associated with FO. UCysC, uNGAL, and uKIM-1 did not significantly correlate with CS-AKI. In exploratory analyses of CS-AKI phenotypes, uCysC and uNGAL were highest in CS-AKI+/FO+ infants. CONCLUSIONS: In this study, uCysC and uNGAL in the early postoperative period were associated with FO at 48 hours. UCysC, uNGAL, and uKIM-1 were not associated with CS-AKI. Further studies should focus on defining expected concentrations of these biomarkers, exploring CS-AKI phenotypes and outcomes, and establishing clinically meaningful endpoints for infants post-cardiac surgery.

Whole-Chest Three-Dimensional Modeling Aids Hybrid Pulmonary Valve Replacement Following Double Switch Operation.

The double switch operation for congenitally corrected transposition of the great arteries (CC-TGA) has been associated with high rates of reintervention, including the need for pulmonary valve replacement. Hybrid interventional approaches can avoid bypass when complex anatomy complicates traditional catheter-based approaches. We present a case of successful transcatheter pulmonary valve replacement via hybrid per-ventricular approach with pre-procedural planning aided by 3D segmentation of skeletal and cardiac anatomy in a patient with surgically corrected CC-GTA.

Characterization of hemodynamics in anomalous aortic origin of coronary arteries using patient-specific modeling.

The anomalous aortic origin of coronary arteries (AAOCA) is a congenital disease that can lead to sudden cardiac death (SCD) during strenuous physical activity. Despite AAOCA being the second leading cause of SCD among young athletes, the mechanism behind sudden cardiac death remains mostly unknown. Computational fluid dynamics provides a powerful tool for studying how pathologic anatomy can affect different hemodynamic states. The present study investigates the effect of AAOCA on patient hemodynamics. We performed patient-specific hemodynamic simulations of interarterial AAOCA at baseline and in the exercise state using our massively parallel flow solver. Additionally, we investigate how surgical correction via coronary unroofing impacts patient blood flow. Results show that patient-specific AAOCA models exhibited higher interarterial time-averaged wall shear stress (TAWSS) values compared to the control patients. The oscillatory shear index had no impact on AAOCA. Finally, the coronary unroofing procedure normalized the elevated TAWSS by decreasing TAWSS in the postoperative patient. The present study provides a proof of concept for the potential hemodynamic factors underlying coronary ischemia in AAOCA during exercise state.

Postoperative Renal Failure, Shunt Type, and Mortality After Norwood Palliation.

BACKGROUND: The Single Ventricle Reconstruction Trial demonstrated increased risk of death or heart transplant 1 year after Norwood among subjects randomly assigned to modified Blalock-Taussig shunts compared with right ventricle to pulmonary artery (RV-PA) shunts. We used the Single Ventricle Reconstruction Trial public use database to evaluate incidence and risk factors for postoperative renal failure and relationships between renal failure, shunt type, and outcomes after Norwood. METHODS: Postoperative renal failure was defined a priori as a threefold rise in creatinine from baseline, or dialysis use, within 7 days of Norwood. We used multivariate logistic regression to evaluate risk factors for postoperative renal failure and Cox hazard regression to determine the association between postoperative renal failure and 1 year after Norwood mortality. RESULTS: Overall, postoperative renal failure occurred in 8.4% (46 of 544) patients with risk factors including receipt of a modified Blalock-Taussig shunt (adjusted odds ratio [aOR] 3.3, P = .02), low center volume (aOR 2.7, P = .005), two or more preoperative complications (aOR 4.0, P < .001), low birth weight (aOR 3.2, P = .002), postoperative heart block (aOR 8.5, P = .001), and delayed sternal closure (aOR 5.3, P = .026). Renal failure was an independent risk factor for 1-year mortality (aHR 1.9, P = .019). Assessing interaction by shunt type, mortality risk associated with renal failure was greatest in the RV-PA shunt group (aHR 3.3 vs RV-PA shunt without renal failure, P = .001), but was also increased in the modified Blalock-Taussig shunt group (aHR 1.9, P = .03). CONCLUSIONS: Postoperative renal failure is common after Norwood and is independently associated with mortality. Although renal failure is more common after modified Blalock-Taussig shunt, the highest mortality risk with renal failure occurs after RV-PA shunt.

Electrocardiogram Before Tricyclic Antidepressant Use: Minimal Impact in Pediatric Functional Gastrointestinal Disorders.

OBJECTIVES: The aim of this study was to determine the effect of electrocardiogram (ECG) findings on the initiation of tricyclic antidepressants (TCAs) for functional gastrointestinal disorders (FGIDs) and to evaluate cardiac outcomes related to low dose TCA use. METHODS: We performed a retrospective chart review of all pediatric outpatients at a tertiary pediatric hospital with an ECG ordered by a pediatric gastroenterologist when considering initiation of a TCA between January 2011 and February 2018. We collected demographics, previous cardiovascular testing results, TCA dosing, and pertinent outcomes, including cardiology referrals, emergency department, and hospital admissions, and death during the study period. All ECGs were reviewed for corrected QT (QTc) interval, heart rate, and other abnormalities. RESULTS: Of 233 patients with screening ECGs, most (84.1%) were prescribed a TCA. Functional abdominal pain or dyspepsia account for 82.0% of diagnoses. Initial TCA dosing of amitriptyline varied widely, 10-50 mg/day, and the dose was not associated with QTc intervals. TCAs were not started in only 1.7% (4/233) due to ECG results. A significant ECG abnormality prompting cardiology referral was found in eight (3.4%) with a prolonged QTc interval in one (0.4%). In 10.7% (25/233) of patients, screening ECG was obtained despite available ECG in the chart. No deaths and no emergency department or hospital visits for arrhythmia or drug overdose occurred. CONCLUSION: Screening ECGs infrequently influence TCA initiation and may lead to increased resource utilization. The overall frequency of cardiology referral due to ECG results is low. Serious adverse cardiac events are unlikely with low dose TCA administration.

Transition to Ductal Stenting for Single Ventricle Patients Led to Improved Survival: An Institutional Case Series.

BACKGROUND: The use of systemic-to-pulmonary shunts (SPS) in neonates with single ventricle heart defects and ductal-dependent pulmonary blood flow (ddPBF) was historically associated with high morbidity and mortality at our center. As a result, we transitioned to the preferential use of ductus arteriosus stents (DS) when feasible. This report describes our initial results with this strategy. METHODS: A single-center study of single ventricle patients that received DS or SPS from 2015 to 2019 was performed to assess whether DS was associated with decreased in-hospital morbidity and increased survival to stage II palliation. RESULTS: A total of 34 patients were included (DS = 11; SPS = 23). Underlying cardiac anomalies were similar between groups and included pulmonary atresia, unbalanced atrioventricular septal defect, and tricuspid atresia. Procedure success was similar between groups (82% vs 83%). Two DS patients were converted to SPS, due to ductal vasospasm or pulmonary artery obstruction, and four SPS patients required surgical shunt revision. In DS patients, postprocedure mechanical ventilation duration was shorter (one vs three days, P = .009) and fewer required postprocedure extracorporeal membrane oxygenation (9% vs 39%, P = .11). A higher proportion of DS patients survived to stage II palliation (100% vs 64%, P = .035), and the probability of one-year survival was higher in DS patients (100% vs 61%, P = .02). CONCLUSIONS: At our center, patients with single ventricle heart defects and ddPBF that received DS experienced reduced in-hospital morbidity and increased survival to stage II palliation compared to SPS.

A systematic review of the evidence supporting post-operative diuretic use following cardiopulmonary bypass in children with Congenital Heart Disease.

BACKGROUND: Paediatric cardiac surgery on cardiopulmonary bypass induces substantial physiologic changes that contribute to post-operative morbidity and mortality. Fluid overload and oedema are prevalent complications, routinely treated with diuretics. The optimal diuretic choice, timing of initiation, dose, and interval remain largely unknown. METHODS: To guide clinical practice and future studies, we used PubMed and EMBASE to systematically review the existing literature of clinical trials involving diuretics following cardiac surgery from 2000 to 2020 in children aged 0-18 years. Studies were assessed by two reviewers to ensure that they met eligibility criteria. RESULTS: We identified nine studies of 430 children across four medication classes. Five studies were retrospective, and four were prospective, two of which included randomisation. All were single centre. There were five primary endpoints - urine output, acute kidney injury, fluid balance, change in serum bicarbonate level, and required dose of diuretic. Included studies showed early post-operative diuretic resistance, suggesting higher initial doses. Two studies of ethacrynic acid showed increased urine output and lower diuretic requirement compared to furosemide. Children receiving peritoneal dialysis were less likely to develop fluid overload than those receiving furosemide. Chlorothiazide, acetazolamide, and tolvaptan demonstrated potential benefit as adjuncts to traditional diuretic regimens. CONCLUSIONS: Early diuretic resistance is seen in children following cardiopulmonary bypass. Ethacrynic acid appears superior to furosemide. Adjunct diuretic therapies may provide additional benefit. Study populations were heterogeneous and endpoints varied. Standardised, validated endpoints and pragmatic trial designs may allow investigators to determine the optimal diuretic, timing of initiation, dose, and interval to improve post-operative outcomes.

Outcomes of Operator-Directed Sedation and Anesthesiologist Care in the Pediatric/Congenital Catheterization Laboratory: A Study Utilizing Data From the IMPACT Registry.

OBJECTIVES: The objective of this study was to assess contemporary use of operator directed sedation (ODS) and anesthesiologist care (AC) in the pediatric/congenital cardiac catheterization laboratory (PCCL), specifically evaluating whether the use of operator-directed sedation was associated with increased risk of major adverse events. BACKGROUND: The safety of ODS relative to AC during PCCL procedures has been questioned. METHODS: A multicenter, retrospective cohort study was performed studying procedures habitually performed with ODS or AC at IMPACT (Improving Adult and Congenital Treatment) registry hospitals using ODS for ≥5% of cases. The risks for major adverse events (MAE) for ODS and AC cases were compared, adjusted for case mix. Current recommendations were evaluated by comparing the ratio of observed to expected MAE for cases in which ODS was inappropriate (inconsistent with those guidelines) with those for similar risk AC cases, as well as those in which ODS or AC was appropriate. RESULTS: Of the hospitals submitting data to IMPACT, 28 of 101 met inclusion criteria. Of the 7,042 cases performed using ODS at these centers, 88% would be inappropriate. Use of ODS was associated with lower likelihood of MAE both in observed results (p < 0.0001) and after adjusting for case-mix (odds ratio: 0.81; p = 0.006). Use of AC was also associated with longer adjusted fluoroscopy and procedure times (p < 0.0001 for both). The observed/expected ratio for ODS cases with high pre-procedural risk (inappropriate for ODS) was significantly lower than that for AC cases with comparable pre-procedural risk. Across a range of pre-procedural risks, there was no stratum in which risk for MAE was lower for AC than ODS. CONCLUSIONS: Across a range of hospitals, ODS was used safely and with improved efficiency. Clinical judgment better identified cases in which ODS could be used than pre-procedural risk score. This should inform future guidelines for the use of ODS and AC in the catheterization laboratory.

An evidence-based review of the use of vasoactive and inotropic medications in post-operative paediatric patients after cardiac surgery with cardiopulmonary bypass from 2000 to 2020.

BACKGROUND: Infants with moderate-to-severe CHD frequently undergo cardiopulmonary bypass surgery in childhood. Morbidity and mortality are highest in those who develop post-operative low cardiac output syndrome. Vasoactive and inotropic medications are mainstays of treatment for these children, despite limited evidence supporting their use. METHODS: To help inform clinical practice, as well as the conduct of future trials, we performed a systematic review of existing literature on inotropes and vasoactives in children after cardiac surgery using the PubMed and EMBASE databases. We included studies from 2000 to 2020, and the patient population was defined as birth - 18 years of age. Two reviewers independently reviewed studies to determine final eligibility. RESULTS: The final analysis included 37 papers. Collectively, selected studies reported on 12 different vasoactive and inotropic medications in 2856 children. Overall evidence supporting the use of these drugs in children after cardiopulmonary bypass was limited. The majority of studies were small with 30/37 (81%) enrolling less than 100 patients, 29/37 (78%) were not randomised, and safety and efficacy endpoints differed widely, limiting the ability to combine data for meta-analyses. CONCLUSION: Vasoactive and inotropic support remain critical parts of post-operative care for children after cardiopulmonary bypass surgery. There is a paucity of data for the selection and dosing of vasoactives and inotropes for these patients. Despite the knowledge gaps that remain, numerous recent innovations create opportunities to rethink the conduct of clinical trials in this high-risk population.

Mustard Baffle Revision With Systemic Ventricular Assist Device Placement.

Systemic right ventricle failure often develops in patients with dextro-transposition of the great arteries who have undergone atrial-level switch procedures. An adult with dextro-transposition of the great arteries with Mustard repair in childhood presented with end-stage heart failure due to systemic right ventricle failure, Mustard baffle leak, and unrepaired partial anomalous pulmonary venous return. She underwent device closure of the baffle leak by catheterization, followed by baffle revision and concomitant systemic ventricular assist device placement by adult and pediatric heart surgeons. This case demonstrates the importance of multidisciplinary collaboration between pediatric and adult heart failure specialists in caring for complex adult congenital heart patients.

Palliating Premature Infants With Obstructed Total Anomalous Pulmonary Venous Connection via Catheterization.

Obstructed total anomalous pulmonary venous connection (TAPVC) involves anomalous drainage of all pulmonary veins to a location other than the left atrium and typically causes significant respiratory symptoms requiring urgent surgical repair. Premature infants born with obstructed TAPVC are often not considered to be suitable surgical candidates due to their size and therefore pose a significant treatment dilemma. Catheter-based interventions provide a temporizing option for infants with obstructed TAPVC, allowing for hemodynamic stabilization and growth until surgical intervention is feasible. We describe the course of two premature infants with obstructed TAPVC who were palliated with stenting of their anomalous pulmonary veins. Both infants required repeat catheter-based intervention for recurrent stenosis and ultimately underwent successful surgical repair at an acceptable weight and corrected gestational age. We propose that a novel catheter-based approach to initial management may be a beneficial option in the premature and low-weight patient population.

Preprocedural three-dimensional planning aids in transcatheter ductal stent placement: A single-center experience.

OBJECTIVES: Describe the use of three-dimensional (3D) patent ductus arteriosus (PDA) modeling to better define ductal anatomy to improve preprocedural planning for ductal stent placement. BACKGROUND: Ductal stenting is an alternative to surgical shunting in patients with ductal dependent pulmonary blood flow. Ductal anatomy is often complex with extreme tortuosity and risk of pulmonary artery isolation, thus increasing procedural risks. METHODS: CT angiograms were segmented to produce 3D PDA models. Ductal morphology was characterized with attention to access approach, degree of pulmonary artery offset/risk of isolation and ductal tortuosity. 3D models were retrospectively compared with biplane angiography. RESULTS: 3D modeling was performed in 12 patients with adequate image quality for complete analysis in 11; median (interquartile range) age/weight 17 days (8-20 days) and 3.1 kg (2.4-3.9 kg). The PDA was reverse oriented in nine with average length of 17.2 ± 2.5 mm and high tortuosity (mean tortuosity index 52, range 3-108). From 3D modeling, two patients were excluded from ductal stenting-extreme ductal tortuosity and threatened pulmonary artery discontinuity, respectively. Ductal stenting was successful in the remaining nine with no major procedural complications. 3D modeling predicted a successful access approach based on the aortic orientation of the ductus in all patients (five carotid, two axillary, two femoral). When comparing 2D angiography with 3D models, angiography consistently underestimated ductal length (-3.2 mm ± 1.6 mm) and tortuosity (-14.8 ± 7.2). CONCLUSIONS: 3D modeling prior to ductal stent placement for ductal dependent pulmonary blood flow is useful in procedural planning, specifically for eligibility, access approach, and accurate ductal measurements. Further studies are needed to determine if 3D planning improves procedural outcomes.