Dexmedetomidine Withdrawal Syndrome in Children in the PICU: Systematic Review and Meta-Analysis.

OBJECTIVES: To systematically review literature describing the clinical presentation, risk factors, and treatment for dexmedetomidine withdrawal in the PICU (PROSPERO: CRD42022307178). DATA SOURCES: MEDLINE/PubMed, Cochrane, Web of Science, and Scopus databases were searched. STUDY SELECTION: Eligible studies were published from January 2000 to January 2022 and reported clinical data for patients younger than 21 years old following discontinuation of dexmedetomidine after greater than or equal to 24 hours of infusion. DATA EXTRACTION: Abstracts identified during an initial search were screened and data were manually abstracted after full-text review of eligible articles. The Newcastle-Ottawa Scale was used to assess study quality. Summary statistics were provided and Spearman rank correlation coefficient was used to identify relationships between covariates and withdrawal signs. A weighted prevalence for each withdrawal sign was generated using a random-effects model. DATA SYNTHESIS: Twenty-three studies (22 of which were retrospective cohort studies) containing 28 distinct cohorts were included. Median cumulative dexmedetomidine exposure by dose was 105.95 µg/kg (range, 30-232.7 µg/kg), median dexmedetomidine infusion duration was 131.75 hours (range, 20.5-525.6 hr). Weighted estimates for proportion (95% CI) of subjects experiencing withdrawal signs across all cohorts were: hypertension 0.34 (range, 0.0-0.92), tachycardia 0.26 (range, 0.0-0.87), and agitation 0.26 (range, 0.09-0.77). Meta-analysis revealed no correlation between dexmedetomidine exposure variables and withdrawal signs. A moderate negative monotonic relationship existed between the proportion of patients who had undergone cardiac surgery and the proportion experiencing hypertension (correlation coefficient, -0.47; p = 0.048) and tachycardia (correlation coefficient, -0.57; p = 0.008), indicating that in cohorts with a higher proportion of patients who were postcardiac surgery, there were fewer occurrences of hypertension and or tachycardia. CONCLUSIONS: On review of the 2000-2022 literature, dexmedetomidine withdrawal may be characterized by tachycardia, hypertension, or agitation, particularly with higher cumulative doses or prolonged durations. Since most studies included in the review were retrospective, prospective studies are needed to further clarify risk factors, establish diagnostic criteria, and identify optimal management strategies.

A shifting landscape: Practice patterns and outcomes of cystic fibrosis and non-cystic fibrosis pediatric lung transplantation.

BACKGROUND: New drugs may further decrease the need for lung transplant (LTx) in pediatric patients with cystic fibrosis (CF), but few studies highlight pediatric non-CF LTx characteristics and outcomes. METHODS: The ISHLT registry was used to report morbidity, graft failure, and survival for primary pediatric (<18 years) LTx performed 1990-2017. Recipient/donor characteristics and long-term outcomes were analyzed for CF and non-CF recipients. Survival was assessed using Kaplan-Meier curves. RESULTS: Of 2232 primary LTx, (43% in males), 918 (41%) were performed for non-CF indications; most commonly pulmonary hypertension (43%). Non-CF patients were younger (median age 11 vs. 15, p < .001), and more frequently on inotropes and/or extracorporeal membrane oxygenation (15% vs. 2.4%, p < .001) at transplant, compared to CF recipients. In-hospital major complications more commonly affected CF LTx recipients (57% vs. 48%, p = .003), but 30-day mortality was higher in the non-CF group (9% non-CF vs. 5% CF, p < .001). One-, five-, and ten-year mortality was 18%, 50%, and 65% for CF recipients, respectively, and 21%, 45%, and 58% for non-CF recipients (p = .01 at 10 years). Five-year survival was significantly better for non-CF females versus CF females (56% vs. 48%, p = .013), but was similar between groups for males (55% vs. 54%, p = .305). While age was a late outcomes risk factor, pulmonary hypertension and later transplants eras were protective. CONCLUSIONS: Early mortality is higher and late mortality is lower in non-CF LTx. Current non-CF LTx outcomes leave room for improvement. Further study is needed to evaluate the effects of center volume and pediatric-specific experience on outcomes.

Cardiac venous malformation in a teenager.

We present the case of a 17-year-old boy with a cardiac venous malformation. This case highlights the diagnostic challenges of such tumours and demonstrates the potential efficacy of a watch-and-wait management approach.

Cost-Effectiveness of Ventricular Assist Device Destination Therapy for Advanced Heart Failure in Duchenne Muscular Dystrophy.

Destination ventricular assist device therapy (DT-VAD) is well accepted in select adults with medically refractory heart failure (HF) who are not transplant candidates; however, its use in younger patients with progressive diseases is unclear. We sought to evaluate the cost-effectiveness of DT-VAD in Duchenne muscular dystrophy (DMD) patients with advanced HF. We created a Markov-state transition model (5-year horizon) to compare survival, costs, and quality of life (QOL) between medical management and DT-VAD in DMD with advanced HF. Model input parameters were derived from the literature. We used sensitivity analyses to explore uncertainty around model assumptions. DT-VAD had higher costs ($435,602 vs. $125,696), survival (3.13 vs. 0.60 years), and quality-adjusted survival (1.99 vs. 0.26 years) than medical management. The incremental cost-effectiveness ratio (ICER) for DT-VAD was $179,086 per quality-adjusted life year (QALY). In sensitivity analyses that were widely varied to account for uncertainty in model assumptions, the DT-VAD strategy generally remained more costly and effective than medical management. Only when VAD implantation costs were <$113,142 did the DT-VAD strategy fall below the $100,000/QALY willingness-to-pay threshold commonly considered to be "cost-effective." In this exploratory analysis, DT-VAD for patients with DMD and advanced HF exceeded societal expectations for cost-effectiveness but had an ICER similar to the accepted practice of DT-VAD in adult HF patients. While more experience and research in this population is needed, our analysis suggests that DT-VAD for advanced HF in DMD should not be dismissed solely based on cost.

Cell-Free Plasma Hemoglobin and Male Gender Are Risk Factors for Acute Kidney Injury in Low Risk Children Undergoing Cardiopulmonary Bypass.

OBJECTIVES: To determine the relationship between the production of cell-free plasma hemoglobin and acute kidney injury in infants and children undergoing cardiopulmonary bypass for cardiac surgery. DESIGN: Prospective observational study. SETTING: Twelve-bed cardiac ICU in a university-affiliated children's hospital. PATIENTS: Children were prospectively enrolled during their preoperative outpatient appointment with the following criteria: greater than 1 month to less than 18 years old, procedures requiring cardiopulmonary bypass, no preexisting renal dysfunction. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Plasma and urine were collected at baseline (in a subset), the beginning and end of cardiopulmonary bypass, and 2 hours and 24 hours after cardiopulmonary bypass in 60 subjects. Levels of plasma hemoglobin increased during cardiopulmonary bypass and were associated (p < 0.01) with cardiopulmonary bypass duration (R = 0.22), depletion of haptoglobin at end and 24 hours after cardiopulmonary bypass (R = 0.12 and 0.15, respectively), lactate dehydrogenase levels at end cardiopulmonary bypass (R = 0.27), and change in creatinine (R = 0.12). Forty-three percent of patients developed acute kidney injury. There was an association between plasma hemoglobin level and change in creatinine that varied by age (overall [R = 0.12; p < 0.01]; in age > 2 yr [R = 0.22; p < 0.01]; and in < 2 yr [R = 0.03; p = 0.42]). Change in plasma hemoglobin and male gender were found to be risk factors for acute kidney injury (odds ratio, 1.02 and 3.78, respectively; p < 0.05). CONCLUSIONS: Generation of plasma hemoglobin during cardiopulmonary bypass and male gender are associated with subsequent renal dysfunction in low-risk pediatric patients, especially in those older than 2 years. Further studies are needed to determine whether specific subgroups of pediatric patients undergoing cardiopulmonary bypass would benefit from potential treatments for hemolysis and plasma hemoglobin-associated renal dysfunction.

Brain Dysplasia Associated with Ciliary Dysfunction in Infants with Congenital Heart Disease.

OBJECTIVE: To test for associations between abnormal respiratory ciliary motion (CM) and brain abnormalities in infants with congenital heart disease (CHD) STUDY DESIGN: We recruited 35 infants with CHD preoperatively and performed nasal tissue biopsy to assess respiratory CM by videomicroscopy. Cranial ultrasound scan and brain magnetic resonance imaging were obtained pre- and/or postoperatively and systematically reviewed for brain abnormalities. Segmentation was used to quantitate cerebrospinal fluid and regional brain volumes. Perinatal and perioperative clinical variables were collected. RESULTS: A total of 10 (28.5%) patients with CHD had abnormal CM. Abnormal CM was not associated with brain injury but was correlated with increased extraaxial cerebrospinal fluid volume (P < .001), delayed brain maturation (P < .05), and a spectrum of subtle dysplasia including the hippocampus (P < .0078) and olfactory bulb (P < .034). Abnormal CM was associated with higher composite dysplasia score (P < .001), and both were correlated with elevated preoperative serum lactate (P < .001). CONCLUSIONS: Abnormal respiratory CM in infants with CHD is associated with a spectrum of brain dysplasia. These findings suggest that ciliary defects may play a role in brain dysplasia in patients with CHD and have the potential to prognosticate neurodevelopmental risks.

Outcomes of pediatric patients undergoing cardiac catheterization while on extracorporeal membrane oxygenation.

The aim of the study is to explore the indications for cardiac catheterization while on extracorporeal membrane oxygenation (ECMO) and the various catheter interventions performed as well as assess the safety profile and determine the short- and intermediate-term survival. ECMO is a lifesaving intervention for pediatric patients with respiratory and/or cardiovascular failure. There is limited recent literature discussing the survival and outcomes of patients undergoing cardiac catheterization while on ECMO. A retrospective review of consecutive patients undergoing catheterization while on ECMO from 2004 to 2013 was performed. Thirty-six patients who underwent 40 cardiac catheterizations were identified. Indications for catheterization included hemodynamic/anatomic assessment of postoperative (16) and non-operative patients (7), planned catheter interventions (CI) (12), and cardiomyopathy assessment (5). CI were performed during 18 (45 %) catheterizations, including stenting of vessels/surgical shunts (9), balloon atrial septostomy (4), device closure of septal defects/vessels (3), thrombolysis of vessels (2), endomyocardial biopsy (2), and temporary pacer wire placement (1). Unexpected diagnostic information was found in 21 (52 %), and 13 patients were referred for surgical intervention. Successful decannulation was achieved in 86 % of patients. Survival to discharge was 72 % and intermediate survival was 69 % (median = 29 months). Survival was 88 % (15/17) among patients who underwent CI. There were six procedural complications (15 %); five vascular and one non-vascular. There were no complications related to patient transport. Cardiac catheterization and interventions while on ECMO are safe, with a survival to discharge of 72 %. Diagnostic information obtained from catheterization leads to management decisions which may impact survival.

Berlin Heart EXCOR pediatric ventricular assist device for bridge to heart transplantation in US children.

BACKGROUND: Recent data suggest that the Berlin Heart EXCOR Pediatric ventricular assist device is superior to extracorporeal membrane oxygenation for bridge to heart transplantation. Published data are limited to 1 in 4 children who received the device as part of the US clinical trial. We analyzed outcomes for all US children who received the EXCOR to characterize device outcomes in an unselected cohort and to identify risk factors for mortality to facilitate patient selection. METHODS AND RESULTS: This multicenter, prospective cohort study involved all children implanted with the Berlin Heart EXCOR Pediatric ventricular assist device at 47 centers from May 2007 through December 2010. Multiphase nonproportional hazards modeling was used to identify risk factors for early (<2 months) and late mortality. Of 204 children supported with the EXCOR, the median duration of support was 40 days (range, 1-435 days). Survival at 12 months was 75%, including 64% who reached transplantation, 6% who recovered, and 5% who were alive on the device. Multivariable analysis identified lower weight, biventricular assist device support, and elevated bilirubin as risk factors for early mortality and bilirubin extremes and renal dysfunction as risk factors for late mortality. Neurological dysfunction occurred in 29% and was the leading cause of death. CONCLUSIONS: Use of the Berlin Heart EXCOR has risen dramatically over the past decade. The EXCOR has emerged as a new treatment standard in the United States for pediatric bridge to transplantation. Three-quarters of children survived to transplantation or recovery; an important fraction experienced neurological dysfunction. Smaller patient size, renal dysfunction, hepatic dysfunction, and biventricular assist device use were associated with mortality, whereas extracorporeal membrane oxygenation before implantation and congenital heart disease were not.

Cerebral regional oxygen saturation and serum neuromarkers for the prediction of adverse neurologic outcome in pediatric cardiac surgery.

BACKGROUND: The aim of this study is to determine the utility of non-invasive bedside neuromonitoring, including cerebral regional oxygen saturation (rSO2) measured by near-infrared spectroscopy and serum biomarkers, in identifying children at risk from adverse neurological outcome after heart surgery. METHODS: Prospective observational study including 39 consecutive children undergoing heart surgery with cardiopulmonary bypass (CPB) and normal neurologic exam prior to surgery. Cerebral rSO2 was measured at baseline (prior to surgery) and then continuously during surgery and for the first 16 h post-operatively. Neuromarkers [neuron-specific enolase (NSE), S100ß, glial fibrillary acidic protein (GFAP), and brain-derived neurotrophic factor (BDNF)] were measured in serum at baseline, immediately after CPB and at 16 h post-operatively. Adverse neurological outcome was defined as an abnormal pediatric cerebral performance category (PCPC) scale score at 12 months after surgery. RESULTS: Sixteen children (41 %) had an abnormal PCPC scale score at the 12-month evaluation after surgery. In children with unfavorable neurological outcomes, mean cerebral rSO2 values were lower and the area-under-the-curve below a threshold of 40 and 20% below baseline were also increased. No significant differences were found in serum neuromarkers between groups at the time points that were assessed. CONCLUSIONS: Bedside determination of cerebral rSO2 may have some utility in identifying children at risk for adverse neurological outcome after heart surgery in children. Additional studies that are sufficiently powered to control for the many covariates in this patient population will be required to fully interrogate this important question. The role of serum neuromarkers in the immediate post-operative period do not appear to be helpful in this question, though more thorough interrogation of delayed periods may ultimately demonstrate some utility in answering this question.

A 1-Day-Old Girl With Infantile Hemangioma and Sternal Cleft.

CASE PRESENTATION: A newborn girl presented to the hospital on the first day of life because of respiratory failure. She was born at home at 37 weeks' gestation with minimal prenatal care and was found to be small for gestational age. The patient was found to have partial sternal agenesis and sternal cleft, cutis aplasia, left facial hemangioma, micrognathia, wide-spaced nipples, and low-set ears. The mother's and baby's urine toxicology screening were positive for amphetamines. Chest radiographs on admission showed bilateral hazy opacities. CT scan of the chest showed an absent sternum with midline chest wall concavity. The patient was monitored preoperatively in the cardiac ICU for risks of arrythmia, respiratory failure, altered cardiac output, and acute cardiopulmonary decompensation.

ACTION-ARC Pediatric and Adult Congenital Heart Disease Ventricular Assist Device Adverse Event Definitions-2023.

Adverse events (AEs) experienced by children and adults with congenital heart disease (CHD) on ventricular assist devices (VADs) are sometimes unique to these populations. The Advanced Cardiac Therapies Improving Outcomes Network (ACTION) and the Academic Research Consortium (ARC) aimed to harmonize definitions of pediatric and CHD AEs for use in clinical trials, registries, and regulatory evaluation. Data from the ACTION registry and adjudication committee were used to adapt general mechanical circulatory support ARC definitions. This ACTION-ARC international expert panel of trialists, clinicians, patients, families, statisticians, biomedical engineers, device developers, and regulatory agencies drafted and iterated definitions harmonized to ACTION data and existing literature during sessions conducted between December 2022 and May 2023, followed by dissemination across clinical/research audiences and professional organizations and further revision. Both email-linked, internet-based surveys and in-person discussions were used as a modified Delphi process. Nineteen AE types were identified and defined, including seven new event types and six event types that were deleted and will no longer be collected, achieving consensus. ACTION-ARC paired rigorous development with methodical stakeholder involvement and dissemination to define pediatric VAD AEs to facilitate assimilation of data across future clinical trials and evaluation of devices for VAD-supported children and adults with CHD.

A prospective multicenter feasibility study of a miniaturized implantable continuous flow ventricular assist device in smaller children with heart failure.

BACKGROUND: There is no FDA-approved left ventricular assist device (LVAD) for smaller children permitting routine hospital discharge. Smaller children supported with LVADs typically remain hospitalized for months awaiting heart transplant-a major burden for families and a challenge for hospitals. We describe the initial outcomes of the Jarvik 2015, a miniaturized implantable continuous flow LVAD, in the NHLBI-funded Pumps for Kids, Infants, and Neonates (PumpKIN) study, for bridge-to-heart transplant. METHODS: Children weighing 8 to 30 kg with severe systolic heart failure and failing optimal medical therapy were recruited at 7 centers in the United States. Patients with severe right heart failure and single-ventricle congenital heart disease were excluded. The primary feasibility endpoint was survival to 30 days without severe stroke or non-operational device failure. RESULTS: Of 7 children implanted, the median age was 2.2 (range 0.7, 7.1) years, median weight 10 (8.2 to 20.7) kilograms; 86% had dilated cardiomyopathy; 29% were INTERMACS profile 1. The median duration of Jarvik 2015 support was 149 (range 5 to 188) days where all 7 children survived including 5 to heart transplant, 1 to recovery, and 1 to conversion to a paracorporeal device. One patient experienced an ischemic stroke on day 53 of device support in the setting of myocardial recovery. One patient required ECMO support for intractable ventricular arrhythmias and was eventually transplanted from paracorporeal biventricular VAD support. The median pump speed was 1600 RPM with power ranging from 1-4 Watts. The median plasma free hemoglobin was 19, 30, 19 and 30 mg/dL at 7, 30, 90 and 180 days or time of explant, respectively. All patients reached the primary feasibility endpoint. Patient-reported outcomes with the device were favorable with respect to participation in a full range of activities. Due to financial issues with the manufacturer, the study was suspended after consent of the eighth patient. CONCLUSION: The Jarvik 2015 LVAD appears to hold important promise as an implantable continuous flow device for smaller children that may support hospital discharge. The FDA has approved the device to proceed to a 22-subject pivotal trial. Whether this device will survive to commercialization remains unclear because of the financial challenges faced by industry seeking to develop pediatric medical devices. (Supported by NIH/NHLBI HHS Contract N268201200001I, clinicaltrials.gov 02954497).

Educating Surgeons to Construct Valved Conduits: What Does It Take to Achieve Reproducible Results?

BACKGROUND: Despite the demonstrated utility of surgeon-fashioned polytetrafluoroethylene (PTFE) valved conduits, methods for educating surgeons to reproducibly construct these conduits are lacking. We present a surgeon education process and early outcomes for children receiving surgeon-fashioned PTFE valved conduits during the initial learning curve. METHODS: The educational curriculum included 4 hours of proctored instruction/supervised valve construction, followed by 2 hours of individual practice. A surgeon with prior mastery of the technique provided templated designs, videos, and follow-up consultation. A retrospective medical record review (2017-2022) described early outcomes and valve function for patients receiving surgeon-fashioned PTFE right ventricle-to-pulmonary artery conduits. RESULTS: Two surgeons were educated using the method described. Fifteen valved conduits were implanted in 14 patients (median patient age, 38 months; conduit size range, 10-24 mm). At discharge, no patient had more than mild stenosis or regurgitation, and 12 of 15 valves (80%) had none or trivial regurgitation. Median follow-up was 14 months (range, 1-52 months). At the last follow-up, median peak conduit gradient of the 15 valves was low (18 mm Hg), 1 (7%) had moderate stenosis, and 1 (7%) had mild-moderate regurgitation. Two conduits were replaced concomitantly during repair of associated lesions at 14 and 38 months (sizes 10 and 12 mm, respectively). There were no deaths and no infectious complications. CONCLUSIONS: Four hours of proctored surgeon education plus deliberate practice is an effective method for teaching valved PTFE conduit construction and is associated with excellent early valve function. This study provides educational methods and initial evidence of safety for congenital surgeons wishing to learn and adopt this technique.

Activated partial thromboplastin time is a better trending tool in pediatric extracorporeal membrane oxygenation.

OBJECTIVES: To determine whether activated partial thromboplastin times are a better heparin management tool than activated clotting times in pediatric extracorporeal membrane oxygenation. DESIGN: A single-center retrospective analysis of perfusion and patient records. SETTING: Academic pediatric tertiary care center. PATIENTS: Pediatric patients (<21 yrs old) requiring extracorporeal membrane oxygenation support initiated at Children's Hospital of Pittsburgh. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Point-of-care activated clotting time and activated partial thromboplastin time values, clinical laboratory activated partial thromboplastin time values, weight-normalized heparin administration (units/kg/hr), and reported outcomes were collected for pediatric patients treated for cardiac and/or respiratory failure with extracorporeal membrane oxygenation. Spearman's ranked correlations were performed for each coagulation test compared to heparin dosage. The Bland-Altman test was used to determine the validity of the point-of-care activated partial thromboplastin time. Hazard analysis was conducted for outcomes and complications for patients whose heparin management was based on the clinical laboratory activated partial thromboplastin time or the activated clotting time. Only the clinical laboratory activated partial thromboplastin time showed a correlation (ρ = 0.40 vs. ρ = -0.04 for activated clotting time) with the heparin administration (units/kg/hr). Point-of-care activated partial thromboplastin time and activated partial thromboplastin time values correlated well (ρ = 0.76), with <5% of samples showing a difference outside 2 SDs, but differences in their absolute values (Δactivated partial thromboplastin time = 100 secs) preclude them from being interchangeable measures. Furthermore, despite no effective change in the mean activated clotting time, cardiac patients showed a significantly improved correlation to heparin dose for all coagulation tests (e.g., point-of-care activated partial thromboplastin time ρ = 0.60). Management of patients with the clinical laboratory activated partial thromboplastin time did not significantly affect patient survival rates but did significantly reduce bleeding complications and significantly increased clotting in the extracorporeal membrane oxygenation circuit. A hazard analysis demonstrated that bleeding complications were associated with an increased risk of mortality, whereas clotting complications in the extracorporeal membrane oxygenation circuit were not. CONCLUSIONS: The activated clotting time is not an accurate monitoring tool for heparin management in pediatricextracorporeal membrane oxygenation. The point-of-care activated partial thromboplastin time correlates well with the clinical laboratory activated partial thromboplastin time but cannot be substituted for the clinical laboratory activated partial thromboplastin time values. Management of pediatric extracorporeal membrane oxygenation patients with the clinical laboratory activated partial thromboplastin time reduced bleeding complications which are associated with increases in mortality.

Plasma exchange in a 13-year-old male with acute intravascular hemolysis and acute kidney injury after placement of a ventricular assist device.

Intravascular hemolysis and resulting plasma-free hemoglobin elevation has been associated with acute kidney injury via several mechanisms. Proximal tubular injury due to iron compound deposition and nitric oxide sequestration with subsequent impairment of the microcirculation and hypoperfusion are specific adverse effects of intravascular hemolysis that may contribute to acute kidney injury. Therefore, removal of plasma-free hemoglobin and restoration of normal nitric oxide vasodilatory mechanisms may play a beneficial role in treating acute kidney injury secondary to acute intravascular hemolysis. We report herein the case of a 13-year-old patient with severe intravascular hemolysis and acute kidney injury and describe the role of plasma exchange with plasma replacement in his successful recovery.

Pulsatile venous waveform quality affects the conduit performance in functional and "failing" Fontan circulations.

OBJECTIVE: To investigate the effect of pulsatility of venous flow waveform in the inferior and superior caval vessels on the performance of functional and "failing" Fontan patients based on two primary performance measures - the conduit power loss and the distribution of inferior caval flow (hepatic factors) to the lungs. METHODS: Doppler angiography flows were acquired from two typical extra-cardiac conduit "failing" Fontan patients, aged 13 and 25 years, with ventricle dysfunction. Using computational fluid dynamics, haemodynamic efficiencies of "failing", functional, and in vitro-generated mechanically assisted venous flow waveforms were evaluated inside an idealised total cavopulmonary connection with a caval offset. To investigate the effect of venous pulsatility alone, cardiac output was normalised to 3 litres per minute in all cases. To quantify the pulsatile behaviour of venous flows, two new performance indices were suggested. RESULTS: Variations in the pulsatile content of venous waveforms altered the conduit efficiency notably. High-frequency and low-amplitude oscillations lowered the pulsatile component of the power losses in "failing" Fontan flow waveforms. Owing to the offset geometry, hepatic flow distribution depended strongly on the ratio of time-dependent caval flows and the pulsatility content rather than mixing at the junction. "Failing" Fontan flow waveforms exhibited less balanced hepatic flow distribution to lungs. CONCLUSIONS: The haemodynamic efficiency of single-ventricle circulation depends strongly on the pulsatility of venous flow waveforms. The proposed performance indices can be calculated easily in the clinical setting in efforts to better quantify the energy efficiency of Fontan venous waveforms in pulsatile settings.

A Minimal Opioid Postoperative Management Protocol in Congenital Cardiac Surgery: Safe and Effective.

There is evidence that reducing opioid exposure in children undergoing cardiac surgery may enhance postoperative recovery. We aimed to describe a minimal opioid postoperative management protocol in children undergoing cardiac surgery and our early outcomes with this strategy. We reviewed the medical records of children (6 months-18 years) who underwent elective cardiac surgery through a median sternotomy with cardiopulmonary bypass at our institution between 2016 and 2018. All patients were managed postoperatively using a standardized protocol. 101 children (median age 5 years) were included and 85% were extubated in the operating room. Although most patients (96%) received opioids postoperatively, opioid requirements decreased steadily over time, with 88%, 58%, and 18% of children receiving opioids on postoperative day 1, 2, and 3, respectively; 41% received no opioids after postoperative day 1. The median cumulative opioid exposure was 0.25 morphine milligram equivalents per kg (interquartile range, 0.10-0.75). Greater than mild pain was rare (<10%) at each time point. The rates of operative mortality and major complication were 0% and 3%, respectively. The median postoperative length of stay was 3 days, and 13% required readmission within 30 days. Age, cardiopulmonary bypass time, and number of benzodiazepine doses were independently associated with cumulative opioid exposure. Any complication, chest tube time, and higher STAT Category were independently associated with prolonged postoperative length of stay. A minimal opioid postoperative management protocol can be safe and effective in children undergoing cardiac surgery. Future prospective studies are needed to determine optimal practice and patient selection.

Capturing Adult Congenital Heart Disease: Framework for Development of an Adult Congenital Heart Disease Mortality Risk Model.

BACKGROUND: As a formative step toward development of adult congenital heart disease (ACHD) risk-adjusted metrics, we describe The Society of Thoracic Surgeons (STS) ACHD population, procedural frequency, and early mortality. METHODS: Adults (≥18 years) with CHD (2014-2019) were identified in the STS Adult Cardiac Surgery (ASCD) and the Congenital Heart Surgery (CHSD) Databases. After deduplication, variable mapping, data concatenation, and harmonization of preprocedure factors, procedures were grouped, and unadjusted mortality was catalogued for the overall cohort and the cohort excluding patients with an isolated bicuspid aortic valve (BAV). RESULTS: Among 171 186 ACSD and 18 281 CHSD records, 152 731 unique records met inclusion criteria. Twenty-eight congenital diagnoses accounted for 86% of the overall cohort, and prevalence of ACHD increased over the study time frame. ACHD patients underwent operations to treat both acquired and CHD. Most common procedures overall and after excluding isolated BAV were aortic valve replacement (AVR), ascending aortic surgery, and coronary artery bypass grafting (CABG). After excluding isolated BAV, major procedure combinations occurred in 46% (31% had 2 major procedures and 3% had ≥4), and the most prevalent combinations included AVR + CABG (n = 2352), AVR + subaortic stenosis repair (n = 1481), and AVR + ascending aortic surgery (n = 1239). Unadjusted 30-day mortality was procedure dependent, 2.8% overall and 3.6% with isolated BAV excluded. CONCLUSIONS: The ACHD surgical population is heterogenous, and patients undergo surgery for CHD-related and adult/acquired procedure combinations. Early mortality is variable and influenced by surgical complexity. Excluding isolated BAV patients and developing procedure-based ACHD mortality risk models may be ideal but will require empirically derived grouping and collaboration.

Platelet activation in ovines undergoing sham surgery or implant of the second generation PediaFlow pediatric ventricular assist device.

The PediaFlow pediatric ventricular assist device (VAD) is a magnetically levitated turbodynamic pump under development for circulatory support of small children with a targeted flow rate range of 0.3-1.5 L/min. As the design of this device is refined, ensuring high levels of blood biocompatibility is essential. In this study, we characterized platelet activation during the implantation and operation of a second generation prototype of the PediaFlow VAD (PF2) and also performed a series of surgical sham studies to examine purely surgical effects on platelet activation. In addition, a newly available monoclonal antibody was characterized and shown to be capable of quantifying ovine platelet activation. The PF2 was implanted in three chronic ovine experiments of 17, 30, and 70 days, while surgical sham procedures were performed in five ovines with 30-day monitoring. Blood biocompatibility in terms of circulating activated platelets was measured by flow cytometric assays with and without exogenous agonist stimulation. Platelet activation following sham surgery returned to baseline in approximately 2 weeks. Platelets in PF2-implanted ovines returned to baseline activation levels in all three animals and showed an ability to respond to agonist stimulation. Late-term platelet activation was observed in one animal corresponding with unexpected pump stoppages related to a manufacturing defect in the percutaneous cable. The results demonstrated encouraging platelet biocompatibility for the PF2 in that basal platelet activation was achieved early in the pump implant period. Furthermore, this first characterization of the effect of a major cardiothoracic procedure on temporal ovine platelet activation provides comparative data for future cardiovascular device evaluation in the ovine model.

Biocompatibility assessment of the first generation PediaFlow pediatric ventricular assist device.

The PediaFlow pediatric ventricular assist device is a miniature magnetically levitated mixed flow pump under development for circulatory support of newborns and infants (3-15 kg) with a targeted flow range of 0.3-1.5 L/min. The first generation design of the PediaFlow (PF1) was manufactured with a weight of approximately 100 g, priming volume less than 2 mL, length of 51 mm, outer diameter of 28 mm, and with 5-mm blood ports. PF1 was evaluated in an in vitro flow loop for 6 h and implanted in ovines for three chronic experiments of 6, 17, and 10 days. In the in vitro test, normalized index of hemolysis was 0.0087 ± 0.0024 g/100L. Hemodynamic performance and blood biocompatibility of PF1 were characterized in vivo by measurements of plasma free hemoglobin, plasma fibrinogen, total plasma protein, and with novel flow cytometric assays to quantify circulating activated ovine platelets. The mean plasma free hemoglobin values for the three chronic studies were 4.6 ± 2.7, 13.3 ± 7.9, and 8.8 ± 3.3 mg/dL, respectively. Platelet activation was low for portions of several studies but consistently rose along with observed animal and pump complications. The PF1 prototype generated promising results in terms of low hemolysis and platelet activation in the absence of complications. Hemodynamic results validated the magnetic bearing design and provided the platform for design iterations to meet the objective of providing circulatory support for young children with exceptional biocompatibility.