Socioeconomic Influences on Outcomes Following Congenital Heart Disease Surgery

Associations between social determinants of health (SDOH) and adverse outcomes for children with congenital heart disease (CHD) are starting to be recognized; however, such links remain understudied. We examined the relationship between community-level material deprivation on mortality, readmission, and length of stay (LOS) for children undergoing surgery for CHD. We performed a retrospective cohort study of patients who underwent cardiac surgery at our institution from 2015 to 2018. A community-level deprivation index (DI), a marker of community material deprivation, was generated to contextualize the lived experience of children with CHD. Generalized mixed-effects models were used to assess links between the DI and outcomes of mortality, readmission, and LOS following cardiac surgery. The DI and components were scaled to provide mean differences for a one standard deviation (SD) increase in deprivation. We identified 1,187 unique patients with surgical admissions. The median LOS was 11 days, with an overall mortality rate of 4.6% and readmission rate of 7.6%. The DI ranged from 0.08 to 0.85 with a mean of 0.37 (SD 0.12). The DI was associated with increased LOS for patients with more complex heart disease (STAT 3, 4, and 5), which persisted after adjusting for factors that could prolong LOS (all p < 0.05). The DI approached but did not meet a significant association with mortality (p = 0.0528); it was not associated with readmission (p = 0.36). Community-level deprivation is associated with increased LOS for patients undergoing cardiac surgery. Future work to identify the specific health-related social needs contributing to LOS and identify targets for intervention is needed.

Modifiable risk factor reduction for pediatric ventricular assist devices and the influence of persistent modifiable risk factors at transplant

OBJECTIVES

Ventricular assist devices (VADs) are associated with a mortality benefit in children. Database-driven analyses have associated VADs with reduction of modifiable risk factors (MRFs), but validation with institutional data is required. The authors studied MRF reduction on VAD and the influence of persistent MRFs on survival after heart transplant.

METHODS

All patients at the authors' institution requiring a VAD at transplant (2011-2022) were retrospectively identified. MRFs included renal dysfunction (estimated glomerular filtration rate <60 mL/min/1.73 m2), hepatic dysfunction (total bilirubin ≥1.2 mg/dL), total parenteral nutrition dependence, sedatives, paralytics, inotropes, and mechanical ventilation.

RESULTS

Thirty-nine patients were identified. At time of VAD implantation, 18 patients had ≥3 MRFs, 21 had 1 to 2 MRFs, and 0 had 0 MRFs. At time of transplant, 6 patients had ≥3 MRFs, 17 had 1 to 2 MRFs, and 16 had 0 MRFs. Hospital mortality occurred in 50% (3 out of 6) patients with ≥3 MRFs at transplant vs 0% of patients with 1 to 2 and 0 MRFs (P = .01 for ≥3 vs 1-2 and 0 MRFs). MRFs independently associated with hospital mortality included paralytics (1.76 [range, 1.32-2.30]), ventilator (1.59 [range, 1.28-1.97]), total parenteral nutrition dependence (1.49 [range, 1.07-2.07]), and renal dysfunction (1.31 [range, 1.02-1.67]). Two late mortalities occurred (3.6 and 5.7 y), both in patients with 1 to 2 MRFs at transplant. Overall posttransplant survival was significantly worse for ≥3 versus 0 MRFs (P = .006) but comparable between other cohorts (P > .1).

CONCLUSIONS

VADs are associated with MRF reduction in children, yet those with persistent MRFs at transplant experience a high burden of mortality. Transplanting VAD patients with ≥3 MRFs may not be prudent. Time should be given on VAD support to achieve aggressive pre-transplant optimization of MRFs.

ECMO Bridge to Lung Transplant in Children with Idiopathic Pulmonary Arterial Hypertension

Idiopathic pulmonary arterial hypertension (IPAH) represents an important clinical indication for lung transplant (LTx) in children. Recent trends show fewer children with IPAH are undergoing LTx nowadays compared to previous time periods, including those with most severe form of the disease. Using the UNOS Registry, we investigated if ECMO at the time of transplant impacts post-transplant survival in children with IPAH. A total of 74 LTx recipients while on ECMO at the time of transplant were identified (IPAH: N = 12). Children with IPAH who underwent LTx while on ECMO had shown comparable survival rates to those who were on ECMO for other conditions. This analysis provides encouraging results, supporting the potential expansion of LTx for this patient population. Given the low number of children undergoing LTx, we think there should be a consensus document to provide better guidance for referring and selecting the high-risk pediatric population with IPAH on ECMO for lung transplant.

Deep Learning for Automated Measurement of Total Cardiac Volume for Heart Transplantation Size Matching

Total Cardiac Volume (TCV)-based size matching using Computed Tomography (CT) is a novel technique to compare donor and recipient heart size in pediatric heart transplant that may increase overall utilization of available grafts. TCV requires manual segmentation, which limits its widespread use due to time and specialized software and training needed for segmentation. This study aims to determine the accuracy of a Deep Learning (DL) approach using 3-dimensional Convolutional Neural Networks (3D-CNN) to calculate TCV, with the clinical aim of enabling fast and accurate TCV use at all transplant centers. Ground truth TCV was segmented on CT scans of subjects aged 0-30 years, identified retrospectively. Ground truth segmentation masks were used to train and test a custom 3D-CNN model consisting of a DenseNet architecture in combination with residual blocks of ResNet architecture. The model was trained on a cohort of 270 subjects and a validation cohort of 44 subjects (36 normal, 8 heart disease retained for model testing). The average Dice similarity coefficient of the validation cohort was 0.94 ± 0.03 (range 0.84-0.97). The mean absolute percent error of TCV estimation was 5.5%. There is no significant association between model accuracy and subject age, weight, or height. DL-TCV was on average more accurate for normal hearts than those listed for transplant (mean absolute percent error 4.5 ± 3.9 vs. 10.5 ± 8.5, p = 0.08). A deep learning-based 3D-CNN model can provide accurate automatic measurement of TCV from CT images. This initial study is limited as a single-center study, though future multicenter studies may enable generalizable and more accurate TCV measurement by inclusion of more diverse cardiac pathology and increasing the training data.

Seventh Annual Society of Thoracic Surgeons Pedimacs Report

BACKGROUND

The Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs), supported by The Society of Thoracic Surgeons, provides detailed information on pediatric patients supported with ventricular assist devices (VADs).

METHODS

From September 19, 2012, to December 31, 2022, 1463 devices in 1219 patients aged <19 years were reported to the registry from 40 North American hospitals.

RESULTS

Cardiomyopathy remains the most common underlying etiology (59%), followed by congenital heart disease (26%) and myocarditis (8%). Implantable continuous devices were most common (39%) type, followed by paracorporeal pulsatile (28%) and paracorporeal continuous (27%) devices. At 6 months after VAD implantation, a favorable outcome (transplant, recovery, or alive on device) was achieved in 85% of patients, which was greatest among those on implantable continuous VADs (92%) and least for paracorporeal continuous VADs (68%), although the patient population supported on these devices is different.

CONCLUSIONS

This Seventh Pedimacs Report demonstrates the continued importance of VADs in the treatment of children. With the complexity of cardiac physiologies and sizes of patients, multiple types of devices are used, including paracorporeal continuous, paracorporeal pulsatile, and implantable continuous devices. The preoperative risk factors and differences in patient populations may account for some of the differences in survival observed among these devices. This report, along with other collaborative work, continues to advance the care of this challenging and vulnerable population.

Unmasking the Impact of Oxygenator Induced Hypocapnia on Blood Lactate in Veno-Arterial Extracorporeal Membrane Oxygenation

Extracorporeal membrane oxygenation (ECMO) is often associated with disturbances in acid/base status that can be triggered by the underlying pathology or the ECMO circuit itself. Extracorporeal membrane oxygenation is known to cause hypocapnia, but the impact of reduced partial pressure of carbon dioxide (pCO2) on biomarkers of tissue perfusion during veno-arterial (VA)-ECMO has not been evaluated. To study the impact of low pCO2 on perfusion indices in VA-ECMO, we placed Sprague-Dawley rats on an established VA-ECMO circuit using either an oxygen/carbon dioxide mixture (O2 95%, CO2 5%) or 100% O2 delivered through the oxygenator (n = 5 per cohort). Animals receiving 100% O2 developed a significant VA CO2 difference (pCO2 gap) and rising blood lactate levels that were inversely proportional to the decrease in pCO2 values. In contrast, pCO2 gap and lactate levels remained similar to pre-ECMO baseline levels in animals receiving the O2/CO2 mixture. More importantly, there was no significant difference in venous oxygen saturation (SvO2) between the two groups, suggesting that elevated blood lactate levels observed in the rats receiving 100% O2 were a response to oxygenator induced hypocapnia and alkaline pH rather than reduced perfusion or underlying tissue hypoxia. These findings have implications in clinical and experimental extracorporeal support contexts.

Donation after circulatory death significantly reduces waitlist times while not changing post-heart transplant outcomes: A United Network for Organ Sharing Analysis

BACKGROUND

Recently, several centers in the United States have begun performing donation after circulatory death (DCD) heart transplants (HTs) in adults. We sought to characterize the recent use of DCD HT, waitlist time, and outcomes compared to donation after brain death (DBD).

METHODS

Using the United Network for Organ Sharing database, 10,402 adult (aged >18 years) HT recipients from January 2019 to June 2022 were identified: 425 (4%) were DCD and 9,977 (96%) were DBD recipients. Posttransplant outcomes in matched and unmatched cohorts and waitlist times were compared between groups.

RESULTS

DCD and DBD recipients had similar age (57 years for both, p = 0.791). DCD recipients were more likely White (67% vs 60%, p = 0.002), on left ventricular assist device (LVAD; 40% vs 32%, p < 0.001), and listed as status 4 to 6 (60% vs 24%, p < 0.001); however, less likely to require inotropes (22% vs 40%, p < 0.001) and preoperative extracorporeal membrane oxygenation (0.9% vs 6%, p < 0.001). DCD donors were younger (29 vs 32 years, p < 0.001) and had less renal dysfunction (15% vs 39%, p < 0.001), diabetes (1.9% vs 3.8%, p = 0.050), or hypertension (9.9% vs 16%, p = 0.001). In matched and unmatched cohorts, early survival was similar (p = 0.22). Adjusted waitlist time was shorter in DCD group (21 vs 31 days, p < 0.001) compared to DBD cohort and 5-fold shorter (DCD: 22 days vs DBD: 115 days, p < 0.001) for candidates in status 4 to 6, which was 60% of DCD cohort.

CONCLUSIONS

The community is using DCD mostly for those recipients who are expected to have extended waitlist times (e.g., durable LVADs, status >4). DCD recipients had similar posttransplant early survival and shorter adjusted waitlist time compared to DBD group. Given this early success, efforts should be made to expand the donor pool using DCD, especially for traditionally disadvantaged recipients on the waitlist.

Up to an Hour of Donor Resuscitation Does Not Affect Pediatric Heart Transplantation Survival

BACKGROUND

In pediatric heart transplantation, surgeons historically avoided donors requiring cardiopulmonary resuscitation (CPR), despite evidence that donor CPR does not change posttransplant survival (PTS). This study sought to determine whether CPR duration affects PTS.

METHODS

All potential brain-dead donors aged <40 years from 2001 to 2021 consented for heart procurement were identified in the United Network for Organ Sharing database (n = 54,671). Organ acceptance was compared by CPR administration and duration. All recipients aged <18 years with donor CPR data were then identified (n = 5680). Survival analyses were conducted using increasing CPR duration as a cut point to identify the shortest duration beyond which PTS worsened. Additional analyses were performed with multivariable and cubic spline regression.

RESULTS

Fifty-one percent of donors (28,012 of 54,671) received CPR. Donor acceptance was lower after CPR (54% vs 66%; P < .001) and across successive quartiles of CPR duration (P < .001). Of the transplant recipients, 48% (2753 of 5680) belonged to the no-CPR group, and 52% (2927 of 5680) belonged to the CPR group. Kaplan-Meier analyses of CPR duration attained significance at 55 minutes, after which PTS worsened (11.1 years vs 9.2 years; P = .025). There was no survival difference between the CPR ≤55 minutes group and the no-CPR group (11.1 years vs 11.2 years; P = .571). A cubic spline regression model confirmed that PTS worsened at more than 55 minutes of CPR. A Cox regression demonstrated that CPR >55 minutes predicted worsened PTS relative to no CPR (HR, 1.51; P = .007) but CPR ≤55 minutes did not (HR, 1.01; P = .864).

CONCLUSIONS

Donor CPR decreases organ acceptance for transplantation; however, shorter durations (≤55 minutes) had equivalent PTS when controlling for other risk factors.

Contemporary Trends in Cardiac Surgical Care for Trisomy 13 and 18 Patients Admitted to Hospitals in the United States

OBJECTIVE

To assess rates of cardiac surgery and the clinical and demographic features that influence surgical vs nonsurgical treatment of congenital heart disease (CHD) in patients with trisomy 13 (T13) and trisomy 18 (T18) in the United States.

STUDY DESIGN

A retrospective study was performed using the Pediatric Health Information System. All hospital admissions of children (<18 years of age) with T13 and T18 in the United States were identified from 2003 through 2022. International Classifications of Disease (ICD) codes were used to identify presence of CHD, extracardiac comorbidities/malformations, and performance of cardiac surgery.

RESULTS

Seven thousand one hundred thirteen patients were identified. CHD was present in 62% (1625/2610) of patients with T13 and 73% (3288/4503) of patients with T18. The most common CHD morphologies were isolated atrial/ventricular septal defects (T13 40%, T18 42%) and aortic hypoplasia/coarctation (T13 21%, T18 23%). Single-ventricle morphologies comprised 6% (100/1625) of the T13 and 5% (167/3288) of the T18 CHD cohorts. Surgery was performed in 12% of patients with T13 plus CHD and 17% of patients with T18 plus CHD. For all cardiac diagnoses, <50% of patients received surgery. Nonsurgical patients were more likely to be born prematurely (P < .05 for T13 and T18). The number of extracardiac comorbidities was similar between surgical/nonsurgical patients with T13 (median 2 vs 2, P = .215) and greater in surgical vs nonsurgical patients with T18 (median 3 vs 2, P < .001). Hospital mortality was <10% for both surgical cohorts.

CONCLUSIONS

Patients with T13 or T18 and CHD receive surgical palliation, but at a low prevalence (≤17%) nationally. Given operative mortality <10%, opportunity exists perhaps for quality improvement in the performance of cardiac surgery for these vulnerable patient populations.

Lung Transplantation for Pulmonary Vascular Disease in Children: A United Network for Organ Sharing Analysis

Pulmonary vascular disease (PVD) represents an important clinical indication for lung transplant (LTx) in infants, children, and adolescents. There is limited information on LTx outcomes in these patients. We explored LTx volumes and post-LTx survival in children with PVD compared to other diagnoses. The UNOS Registry was queried from 1989 to 2020 to identify first-time pediatric LTx recipients (< 18 yo). PVD was categorized as idiopathic pulmonary arterial hypertension (IPAH) and non-idiopathic arterial hypertension (non-IPAH) and compared to all other patients as other diagnoses. Univariate and multivariate regression models were performed. 984 pediatric LTx patients (593 before 2010 and 391 during/after 2010) were identified, of which 145 (14.7%) had PVD. There has been no significant change in annual rate of all LTxs over comparative eras. However, there has been a decrease in rate of LTxs for PVD patients. Children with PVD had similar survival to other LTx groups in the early era (p = 0.2) and the latter era (p = 0.9). Univariate Cox models, showed that LTx in patients with PVD was associated with a significantly less risk of mortality for children aged 6-11 years compared to younger and older cohorts (HR = 0.4 [0.17-0.98]; p = 0.045), whereas multivariate analysis showed a trend toward higher mortality in 11-17-year-olds (HR = 1.54 [0.97-2.45]; p = 0.06). For PVD patients, oxygen supplementation and ventilator support at LTx were associated with worse post-transplant survival (p = 0.029 and p = 0.01). There has been a decrease in LTx volume for pediatric patients with PVD in the modern era. Post-LTx outcomes for children with PVD are similar to those of other diagnoses in both eras, with children aged 6-11 years having the best survival. Given these findings, LTx should be considered for this patient population.

National experience with pediatric surgical aortic valve repair: A Pediatric Health Information System analysis

OBJECTIVE

To characterize national experience with surgical aortic valve repair in pediatric patients.

METHODS

Patients in the Pediatric Health Information System database aged 17 years or younger with International Statistical Classification of Diseases and Related Health Problems codes for open aortic valve repair from 2003 to 2022 were included (n = 5582). Outcomes of reintervention during index admission (repeat repair, n = 54; replacement, n = 48; and endovascular intervention, n = 1), readmission (n = 2176), and in-hospital mortality (n = 178) were compared. A logistic regression was performed for in-hospital mortality.

RESULTS

One-quarter (26%) of patients were infants. The majority (61%) were boys. Heart failure was present in 16% of patients, congenital heart disease in 73%, and rheumatic disease in 4%. Valve disease was insufficiency in 22% of patients, stenosis in 29%, and mixed in 15%. The highest quartile of centers by volume (median, 101 cases; interquartile range, 55-155 cases) performed half (n = 2768) of cases. Infants had the highest prevalence of reintervention (3%; P < .001), readmission (53%; P < .001), and in-hospital mortality (10%; P < .001). Previously hospitalized patients (median, 6 days; interquartile range, 4-13 days) were at higher risk for reintervention (4%; P < .001), readmission (55%; P < .001), and in-hospital mortality (11%; P < .001), as were patients with heart failure (reintervention [6%; P < .001], readmission [42%; P = .050], and in-hospital mortality [10%; P < .001]). Stenosis was associated with reduced reintervention (1%; P < .001) and readmission (35%; P = .002). The median number of readmissions was 1 (range, 0-6) and time to readmission was 28 days (interquartile range, 7-125 days). A regression of in-hospital mortality identified heart failure (odds ratio, 3.05; 95% CI, 1.59-5.49), inpatient status (odds ratio, 2.40; 95% CI, 1.19-4.82), and infancy (odds ratio, 5.70; 95% CI, 2.60-12.46) as significant.

CONCLUSIONS

The Pediatric Health Information System cohort demonstrated success with aortic valve repair; however, early mortality remains high in infants, hospitalized patients, and patients with heart failure.

Reality of DCD donor use in pediatric thoracic transplantation in the United States

In the US, the first pediatric donation after circulatory death (DCD) thoracic transplant was done in 2004; however, ethical controversy led to minimal utilization of these donors. The present study was performed to characterize the current state of pediatric DCD heart and lung transplantation (HTx, LTx). Children (<18 year old) who underwent HTx or LTx using DCD donors from June 2004 to June 2022 were identified in the United Network for Organ Sharing registry. A total of 14 DCD recipients were identified: 7 (50%) HTx and 7 (50%) LTx. Donor and recipient demographics are described in Table 1. One and 5-year post-transplant survival were as follows: HTx recipients (64% for each) and LTx recipients (86%, 55%). Although often discussed, the national experience with DCD donors for pediatric HTx and LTx remains limited and not being practiced consistently by any pediatric program. Given the critical organ shortage, DCD use in the field of pediatric thoracic transplantation should be strongly considered.

Deep Learning for Automated Measurement of Total Cardiac Volume for Heart Transplantation Size Matching

Background

Total Cardiac Volume (TCV) based size matching using Computed Tomography (CT) is a novel technique to compare donor and recipient heart size in pediatric heart transplant that may increase overall utilization of available grafts. TCV requires manual segmentation, which limits its widespread use due to time and specialized software and training needed for segmentation.

Objective

This study aims to determine the accuracy of a Deep Learning (DL) approach using 3-dimensional Convolutional Neural Networks (3D-CNN) to calculate TCV, with the clinical aim of enabling fast and accurate TCV use at all transplant centers.

Materials and Methods

Ground truth TCV was segmented on CT scans of subjects aged 0-30 years, identified retrospectively. Ground truth segmentation masks were used to train and test a custom 3D-CNN model consisting of a Dense-Net architecture in combination with residual blocks of ResNet architecture.

Results

The model was trained on a cohort of 270 subjects and a validation cohort of 44 subjects (36 normal, 8 heart disease retained for model testing). The average Dice similarity coefficient of the validation cohort was 0.94 ± 0.03 (range 0.84-0.97). The mean absolute percent error of TCV estimation was 5.5%. There is no significant association between model accuracy and subject age, weight, or height. DL-TCV was on average more accurate for normal hearts than those listed for transplant (mean absolute percent error 4.5 ± 3.9 vs. 10.5 ± 8.5, p = 0.08).

Conclusion

A deep learning based 3D-CNN model can provide accurate automatic measurement of TCV from CT images.

Is the practice of using oversized organs for recipients with elevated pulmonary vascular resistance justified?

OBJECTIVE

The purpose of this study was to assess post-transplantation outcomes in recipients with increased pulmonary vascular resistance (PVR) in relation to donor size.

METHODS

The United Network for Organ Sharing database was used to identify patients ages 0 to 18 years at time of listing who underwent transplantation from 2010 to 2019 and for whom cardiac catheterization and donor-recipient weight ratio data were available. Patients were divided according to listing PVR into <3, 3 to 6, and >6 Wood units. Donor-recipient weight ratio was categorized as undersized (≤0.80), midsize (0.81-1.2), and oversized (>1.2). Subgroup analysis was done with an additional supersized group (>2.0).

RESULTS

Fourteen hundred ninety-one patients met study criteria. Median age was 10 (interquartile range, 3-15) years and 45% were female. Four percent of heart transplantation cases used undersized, 45% used midsize, and 51% used oversized organs. More patients with PVR >6 were received an oversized organ transplant compared with patients with PVR <3; 59% (148/252) versus 48% (430/894); P = .003. There was no difference in survival among organ size groups regardless of PVR; this includes patients with PVR >6 at listing who received an oversized organ transplant versus an undersized (P = .359) or midsized (P = .956) organ. In subgroup analysis, even in patients who received a supersized organ transplant, there was no survival difference noted regardless of PVR.

CONCLUSIONS

Despite a persistent practice pattern to transplant oversized organs in high-PVR patients, there remains no difference in post-transplantation survival among these patients and those who received smaller organ transplants. Therefore, transplants in patients with high PVR should not be delayed by waiting for larger donors.

Improved donor lung size matching by estimation of lung volumes based on chest X-ray measurements

RATIONALE

Organ size matching is an important determinant of successful allocation and outcomes in lung transplantation. While computed tomography (CT) is the gold standard, it is rarely used in an organ-donor context, and chest X-ray (CXR) may offer a practical and accurate solution in estimating lung volumes for donor and recipient size matching. We compared CXR lung measurements to CT-measured lung volumes and traditional estimates of lung volume in the same subjects.

METHODS

Our retrospective study analyzed clinically obtained CXR and CT lung images of 250 subjects without evidence of lung disease (mean age 9.9 ± 7.8 years; 129 M/121F). From CT, each lung was semi-automatically segmented and total lung volumes were quantified. From anterior-posterior CXR view, each lung was manually segmented and areas were measured. Lung lengths from the apices to the mid-basal regions of each lung were measured from CXR. Quantified CT lung volumes were compared to the corresponding CXR lung lengths, CXR lung areas, height, weight, and predicted total lung capacity (pTLC).

RESULTS

There are strong and significant correlations between CT volumes and CXR lung areas in the right lung (R2  = .89, p < .0001), left lung (R2  = .87, p < .0001), and combined lungs (R2  = .89, p < .0001). Similar correlations were seen between CT volumes and CXR measured lung lengths in the right lung (R2  = .79, p < .0001) and left lung (R2  = .81, p < .0001). This correlation between anatomical lung volume (CT) and CXR was stronger than lung-volume correlation to height (R2  = .66, p < .0001), weight (R2  = .43, p < .0001), or pTLC (R2  = .66, p < .0001).

CONCLUSION

CXR measures correlate much more strongly with true lung volumes than height, weight, or pTLC. The ability to obtain efficient and more accurate lung volume via CXR has the potential to change our current listing practices of using height as a surrogate for lung size, with a case example provided.

Widening care gap in VAD therapy

BACKGROUND

The removal of the HeartWare ventricular assist device (HVAD) due to pump malfunctions and inferior outcomes compared to HeartMate 3 (HM3) in adults has created a care gap for younger patients. It is unclear if the reported HVAD survival differs by age and if the initial experience with HM3 can bridge the gap.

METHODS

Using the Society of Thoracic Surgeons (STS) Intermacs and Pedimacs registries, durable ventricular assist device (VAD) implants between September 2012 and December 2021 were identified. Young adults (YA) were defined as <40 years old in Intermacs. Patients were excluded if they had an isolated right VAD (RVAD) or were implanted as destination therapy (DT). Survival analysis by Kaplan-Meier (KM) and competing outcomes curves was performed, and 1-year survival is reported.

RESULTS

The Intermacs cohort consisted of YA (n = 1226; HVAD 818; HM3 408) with a median age of YA of 32.07 (26.66-36.27) years and weight (wt) of 83.2 (68-104.2) kg. Most had cardiomyopathy (CM) (92.2%). The Pedimacs cohort was 668 patients (median age 9.47 [1.82-14.23] years, wt 27.2 [10-57.05] kg), and most also had CM (70.5%). Device breakdown included HVAD (n = 326), Berlin EXCOR (n = 277), and HM3 (n = 65). HVAD survival differed by age in adults, with YA fairing better than adults >40 years old (88.8% vs 79.4% at 1 year, p < 0.0001). YA survival was also better compared to Pedimacs patient (88.9% vs 83.7%, p = 0.0002), but when competing events were analyzed, mortality was similar to YA (9.2% vs 9.6%, p = 0.1) with a higher proportion of patient undergoing transplant at 1 year in Pedimacs (74% vs 31.3%, p < 0.0001). Survival by device differed between HVAD and HM3 in YA (88.8% vs 94.4%, p = 0.0025). This difference in device survival was not seen in all children (83.7% vs 87.3%, p = 0.21), including those ≥25 kg. Adverse event profiles also differed across the groups with adults seeing less adverse events with the HM3, but the same was not found (including stroke) in the pediatric cohort. Survival outcomes for patients between 10 and 25 kg were similar with the HVAD compared to the Berlin Heart EXCOR (p = 0.4290), with similarities in stroke risk.

CONCLUSION

The removal of the HVAD device may result in a care gap in younger patient whose survival outcomes do not mirror that of older adults. The HM3 can fill a portion of this gap with good survival, but there remains a subset of pediatric patients that, based on initial HM3 use, will no longer have access to intracorporeal support and therefore, despite reasonable outcomes with the Berlin Heart EXCOR, will not be able to be discharged home. Lastly, it is essential that future changes to the availability of devices take into account the various patient populations that utilize the device to avoid unintended consequences of access inequality.

Hand-Constructed CorMatrix Tubular Valve Used for Tricuspid Valve Replacement in Neonate With Congenital Tricuspid Dysplasia: Five-Year Follow-Up

Tricuspid valve (TV) dysplasia is a rare congenital defect that, in severe cases, can cause heart failure necessitating surgical correction. TV replacement options are limited in neonates since few commercial valves are available and the rates of failure and postoperative mortality are high. The authors report a neonate with TV dysplasia who underwent replacement with a hand-constructed tube valve using small intestinal submucosal extracellular matrix, which functioned well for >5 years.

Exogenous nitric oxide delivery protects against cardiopulmonary bypass-associated acute kidney injury: Histologic and serologic evidence from an ovine model

OBJECTIVE

Several human studies have associated nitric oxide administration via the cardiopulmonary bypass circuit with decreased incidence of cardiopulmonary bypass-associated acute kidney injury, but histopathologic and serologic evidence of nitric oxide efficacy for acute kidney injury attenuation are lacking.

METHODS

By using a survival ovine model (72 hours), acute kidney injury was induced by implementing low-flow cardiopulmonary bypass for 2 hours, followed by full-flow cardiopulmonary bypass for 2 hours. The nitric oxide cohort (n = 6) received exogenous nitric oxide through the cardiopulmonary bypass circuit via the oxygenator, and the control group (n = 5) received no nitric oxide. Serial serologic biomarkers and renal histopathology were obtained.

RESULTS

Baseline characteristics (age, weight) and intraoperative parameters (cardiopulmonary bypass time, urine output, heart rate, arterial pH, and lactate) were equivalent (P > .10) between groups. Postoperatively, urine output, heart rate, respiratory rate, and peripheral arterial saturation were equivalent (P > .10) between groups. Post-cardiopulmonary bypass creatinine elevations from baseline were significantly greater in the control group versus the nitric oxide group at 16, 24, and 48 hours (all P < .05). Histopathologic evidence of moderate/severe acute kidney injury (epithelial necrosis, tubular slough, cast formation, glomerular edema) occurred in 60% (3/5) of the control group versus 0% (0/6) of the nitric oxide group. Cortical tubular epithelial cilia lengthening (a sensitive sign of cellular injury) was significantly greater in the control group than in the nitric oxide group (P = .012).

CONCLUSIONS

In a survival ovine cardiopulmonary bypass model, nitric oxide administered with cardiopulmonary bypass demonstrated serologic and histologic evidence of renal protection from acute kidney injury. These results provide insight into 1 potential mechanism for cardiopulmonary bypass-associated acute kidney injury and supports continued study of nitric oxide via cardiopulmonary bypass circuit for prevention of acute kidney injury.

Survival in Pediatric Patients With Ventricular Assist Devices: A Special Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs) Report

BACKGROUND

The Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs) provides detailed understanding on pediatric patients supported with ventricular assist devices (VADs). We sought to identify important variables affecting mortality in pediatric VADs.

METHODS

Patients aged <19 years, from 2012 to 2021, were included. Survival analyses were performed using Kaplan-Meier. Parametric hazard modeling was used to identify risk factors for death.

RESULTS

Of the 1109 patients, the most common devices were implantable continuous (IC, 448 [40%]), followed by paracorporeal pulsatile (PP, 306 [28%]), paracorporeal continuous (PC, 293 [26%]), and percutaneous (58 [5%]). Patients with percutaneous device, infants, congenital heart disease, biventricular support, and Interagency Registry for Mechanically Assisted Circulatory Support profile 1 had worse overall survival at 6 months. Positive outcome was 83% at 6 months. Consistent with their cohort composition, device type positive outcomes at 6 months were IC, 92%; PP, 84%; and PC, 69%. Parametric hazard modeling for overall survival showed an early hazard for death with biventricular support, congenital heart disease (CHD), intubation before implantation, PC device, and renal impairment, whereas a constant hazard was associated with ascites. For patients <10 kg, parametric modeling showed an early hazard for CHD, intubation, and renal impairment. Modeling in CHD patients showed an early hazard for biventricular support, renal impairment, and use of PC/PP devices.

CONCLUSIONS

This multivariable analysis of the complete Pedimacs database demonstrates that illness at VAD implantation, diagnosis, and strategy of support affect survival and differ by device type. We hope this is the first step in creating a predictive tool to help providers and families have informed expectations.

Expanding use of the HeartMate 3 ventricular assist device in pediatric and adult patients within the Advanced Cardiac Therapies Improving Outcomes Network (ACTION)

BACKGROUND

We report current outcomes in patients supported with the HeartMate 3 (HM3) ventricular assist device in a multicenter learning network.

METHODS

The Advanced Cardiac Therapies Improving Outcomes Network database was queried for HM3 implants between 12/2017 and 5/2022. Clinical characteristics, postimplant course, and adverse events were collected. Patients were stratified according to body surface area (BSA) (<1.4 m2, 1.4-1.8 m2, and >1.8 m2) at device implantation.

RESULTS

During the study period, 170 patients were implanted with the HM3 at participating network centers, with median age 15.3years; 27.1% were female. Median BSA was 1.68 m2; the smallest patient was 0.73 m2 (17.7 kg). Most (71.8%) had a diagnosis of dilated cardiomyopathy. With a median support time of 102.5days, 61.2% underwent transplantation, 22.9% remained supported on device, 7.6% died, and 2.4% underwent device explantation for recovery; the remainder had transferred to another institution or transitioned to a different device type. The most common adverse events included major bleeding (20.8%) and driveline infection (12.9%); ischemic and hemorrhagic stroke were encountered in 6.5% and 1.2% of patients, respectively. Patients with BSA <1.4 m2 had a higher incidence of infection, renal dysfunction, and ischemic stroke.

CONCLUSIONS

In this updated cohort of predominantly pediatric patients supported with the HM3 ventricular assist device, outcomes are excellent with <8% mortality on device. Device-related adverse events including stroke, infection, and renal dysfunction were more commonly seen in smaller patients, highlighting opportunities for improvements in care.

Single Center Experience With Durable Continuous Flow Single Ventricle Assist Device: A Viable Option in Fontan Circulatory Failure

Ventricular assist devices are increasingly used for patients with single ventricle physiology. We describe the use of durable, continuous flow, single ventricular assist device (SVAD) therapy in Fontan circulatory failure patients. Retrospective, single-center review of patients with Fontan circulation implanted with a SVAD between 2017 and 2022. Patient characteristics and outcomes were obtained by chart review. Nine patients underwent SVAD implantation (median age 24 years). Most patients had a total cavopulmonary connection; one had an atriopulmonary Fontan. Five patients had a systemic right ventricle. SVAD was most often utilized as bridge to candidacy (67%). Eight patients had at least moderate systemic ventricular systolic dysfunction. SVAD support continued for a median of 65 days (longest duration, 1,105 days) and one patient remains on support at time of submission. Of five patients discharged home, median length of stay after SVAD was 24 days. Six patients were transplanted (median 96 days from SVAD). Two patients died from pretransplant multisystem organ failure before transplant. All transplanted patients remain alive (median time since transplant 593 days). Continuous flow SVAD therapy can be effective for patients with Fontan circulatory failure and systolic dysfunction. Further studies should investigate feasibility and optimal SVAD timing with more advanced Fontan associated end-organ dysfunction.

The majority of pediatric Fontan patients have excellent post-transplant survival

OBJECTIVE

Many pediatric Fontan patients require heart transplant, but this cohort is understudied given the difficulty in identifying these patients in national registries. We sought to characterize survival post-transplant in a large cohort of pediatric patients undergoing the Fontan.

METHODS

The United Network for Organ Sharing and Pediatric Health Information System were used to identify Fontan heart transplant recipients aged less than 18 years (n = 241) between 2005 and 2022. Decompensation was defined as the presence of extracorporeal membrane oxygenation, ventilation, hepatic/renal dysfunction, paralytics, or total parenteral nutrition at transplant.

RESULTS

Median age at transplant was 9 (interquartile range, 5-12) years. Median waitlist time was 107 (37-229) days. Median volume across 32 center was 8 (3-11) cases. Approximately half (n = 107, 45%) of recipients had 1A/1 initial listing status. Sixty-four patients (28%) were functionally impaired at transplant, 10 patients (4%) were ventilated, and 18 patients (8%) had ventricular assist device support. Fifty-nine patients (25%) had hepatic dysfunction, and 15 patients (6%) had renal dysfunction. Twenty-one patients (9%) were dependent on total parenteral nutrition. Median postoperative stay was 24 (14-46) days, and in-hospital mortality was 7%. Kaplan-Meier analysis showed 1- and 5-year survivals of 89% (95% CI, 85-94) and 74% (95% CI, 81-86), respectively. Kaplan-Meier of Fontan patients without decompensation (n = 154) at transplant demonstrated 1- and 5-year survivals of 93% (95% CI, 88-97) and 88% (95% CI, 82-94), respectively. In-hospital mortality was higher in decompensated patients (11% vs 4%, P = .023). Multivariable analysis showed that decompensation predicted worse post-transplant survival (hazard ratio, 2.47; 95% CI, 1.16-5.22; P = .018), whereas older age at transplant predicted superior post-transplant survival (hazard ratio, 0.89/year; 95% CI, 0.80-0.98; P = .019).

CONCLUSIONS

Pediatric Fontan post-transplant outcomes are promising, although early mortality remains high. For nondecompensated pediatric patients at transplant without end-organ disease (>63% of cohort), early mortality is circumvented and post-transplant survival is excellent and similar to all pediatric transplantation.

Body mass index percentage and survival in pediatric patients listed for lung transplantation: A modern-era multi-institutional analysis

BACKGROUND

Prior studies suggest that being underweight by body mass index percentiles (BMI%) or thinness grade did not affect post-transplant survival in pediatric lung transplant (LTx) recipients regardless of cystic fibrosis (CF) or non-CF diagnosis. Graft and overall survival from the time of listing was instead evaluated based on listing BMI%, the current standard of practice for BMI definitions in pediatrics, to ascertain the impact of a "severely low" subcategory.

METHODS

The UNOS registry was queried for children listed for LTx (aged 2 to <18 years) from January 1986 to March 2020. BMI% at listing and transplant were calculated per CDC guidelines according to age in years, sex, and reported BMI%. Patients were divided by listing BMI%: severely low (<3rd), low (3-<5th), normal (5-<85th), overweight (85-<95th), and obese (≥95th). Kaplan-Meier curves were generated to assess differences in overall survival since listing based on BMI% classes. Cox proportional-hazards models were developed to assess risk factors for overall and graft survival, including listing BMI%, transplant listing era (≥2005), and listing age, by reporting hazard ratios (HR).

RESULTS

Listing BMI% was calculable for 1,876 patients. The proportion of patients with CF differed significantly between BMI% groups (p < 0.001). Patients listed with a non-CF diagnosis comprised 34% of those in the severely low category, and 88% of those listed with an obese BMI%. Compared to patients with a normal listing BMI%, the cohort with severely low BMI% had worse overall survival regardless of LTx (p = 0.009) and graft survival (p = 0.034). Compared to patients with a low BMI%, those with a severely low BMI% had significantly poorer graft survival as well (p = 0.040). Mean graft survival was not significantly different between groups that remained at listing BMI% vs those that improved in category despite an overall small sample size. Independent predictors of poorer survival from the time of listing include severely low vs low-normal BMI% (HR = 1.20) and listing age (HR = 1.02).

CONCLUSION

The proportion of children listed at severely low BMI% has steadily decreased with time, yet pediatric LTx candidates listed with a severely low BMI% had poorer graft and overall survival compared to those of normal BMI%. Severely low listing BMI% was an independent prognostic factor for higher mortality risk from the time of placement on the waitlist. BMI% may be a modifiable target for improving survival regardless of transplantation.

Center volume effect on acute cellular rejection and outcomes in pediatric lung transplant recipients

BACKGROUND

Acute cellular rejection (ACR) is common after lung transplant (LTx). We sought to determine if transplant center volume affected ACR-related outcomes in children after LTx.

METHODS

The United Network for Organ Sharing (UNOS) Registry was queried for patients <18-years-of-age who underwent LTx 1987-2020. Cohorts were children who survived the first-year post transplant and were treated for ACR within that first year (ACR group) and those not treated for ACR (non-ACR). LTx center volume was defined as: high volume center (HVC) (>5LTxs/year), medium volume center (MVC) (>1≤5 LTxs/year), and low volume center (LVC) (≤1LTxs/year).

RESULTS

1320 patients were enrolled into the study; 269 (20.4%) did not experience ACR. The ACR cohort was older (median 14 [11-16] vs 13 [7-16] years, p < 0.001), female (65.3% vs 57.3%, p = 0.016), had cystic fibrosis (62.3% vs 45.5%, p < 0.001), and had a higher lung allocation score (37.3 [34.6-47.8] vs 35.8 [33-42.6], p = 0.029). The ACR cohort trended (p = 0.06) towards lower survival at 5-year (37% vs 47%) and 10-year (25% vs 34%) post-LTx. Among children at HVCs, ACR occurred in 17% of recipients (n = 98/574), compared to 18.5% (n = 73/395) at MVCs and 27% (n = 100/369) at LVCs. Children treated for ACR at HVCs had higher survival than LVCs at 5-years (52% vs 29%) and 10-years (36% vs 15%) (p < 0.001) but similar survival to MVCs at 5-years (52% vs 43%) and 10-years (36% vs 24%) (p = 0.081). No survival differences were detected in MVCs vs LVCs (p = 0.14).

CONCLUSIONS

ACR treated within the first post-LTx year influence survival of children. ACR incidence was lowest at higher volume centers whereas post-ACR treatment survival outcomes were also superior.

Atrial arrhythmias following lung transplant: a single pediatric center experience

Background

Outcomes after lung transplant (LTx) in children have slowly improved. Although atrial arrhythmia (AA) is a common and adverse complication following LTx among adults, there is limited data on pediatric recipients. We detail our pediatric single-center experience while providing further insights on occurrence and management of AA following LTx.

Methods

A retrospective analysis of LTx recipients at a pediatric LTx program from 2014 to 2022 was performed. We investigated timing of occurrence and management of AA following LTx, and its effect on post-LTx outcome.

Results

Three out of nineteen (15%) pediatric LTx recipients developed AA. The timing of occurrence was 9-10 days following LTx. Those patients in the older age group (age >12 years old) were the only ones who developed AA. Developing AA did not have a negative effect on hospital stay duration or short-term mortality. All LTx recipients with AA were discharged home on therapy that was discontinued at 6 months for those who was on mono-therapy without recurrence of AA.

Conclusions

AA is an early post-operative complication in older children and younger adults undergoing LTx at a pediatric center. Early recognition and aggressive management can mitigate any morbidity or mortality. Future investigations should explore factors that place this population at risk for AA in order to prevent this complication post-operatively.

In the era of outpatient ventricular assist devices, is it time to reconsider the practice of bridging older children to transplant on outpatient inotropes?

OBJECTIVE

Ventricular assist devices (VADs) and inotropes are feasible modalities to bridge children to heart transplant (HT) in outpatient settings. However, it is unclear which modality yields superior clinical status at HT and posttransplant survival.

METHODS

The United Network for Organ Sharing was used to identify patients aged 18 years or younger, weighing >25 kg, from 2012 to 2022 who were outpatients at HT (n = 835). Patients were grouped by bridging modality at HT: VAD (n = 235 [28%]), inotropes (n = 176 [21%]), or neither (no support) (n = 424 [50%]).

RESULTS

VAD patients were of similar age (P = .260) but heavier (P = .007) and more likely to have dilated cardiomyopathy (P < .001) than their inotrope counterparts. VAD patients had similar clinical status at HT but superior functional status (performance scale >70%) (59% vs 31%) (P < .001). Overall posttransplant survival in VAD patients (1-year and 5-year survival, 97% and 88%, respectively) was comparable to patients with no support (93% and 87%, respectively) (P = .090) and those on inotropes (98% and 83%, respectively) (P = .089). One-year conditional survival was superior for VAD vs inotrope (2-year and 6-year survival, 96% and 91%, respectively vs 97% and 79%, respectively) (P = .030) and 5-year conditional survival for VAD patients was superior to inotrope (7-year and 10-year survival, 100% and 100%, respectively vs 100% and 88%, respectively) (P = .022) and no support (100% and 83%, respectively) (P = .011).

CONCLUSIONS

Consistent with prior studies, short-term outcomes for pediatric patients bridged to HT in the outpatient setting with VAD or inotropes is excellent. However, compared with outpatients bridged to HT on inotropes, outpatient VAD support allowed for better functional status at HT and superior late posttransplant survival.

Racial disparity exists in the utilization and post-transplant survival benefit of ventricular assist device support in children

PURPOSE

Children of minority race and ethnicity experience inferior outcomes postheart transplantation (HTx). Studies have associated ventricular assist device (VAD) bridge-to-transplant (BTT) with similar-to-superior post-transplant-survival (PTS) compared to no mechanical circulatory support. It is unclear whether racial and ethnic discrepancies exist in VAD utilization and outcomes.

METHODS

The United Network for Organ Sharing (UNOS) database was used to identify 6,121 children (<18 years) listed for HTx between 2006 and 2021: black (B-22% of cohort), Hispanic (H-21%), and white (W-57%). VAD utilization, outcomes, and PTS were compared between race/ethnicity groups. Multivariable Cox proportional analyses were used to study the association of race and ethnicity on PTS with VAD BTT, using backward selection for covariates.

RESULTS

Black children were most ill at listing, with greater proportions of UNOS status 1A/1 (p < 0.001 vs H & W), severe functional limitation (p < 0.001 vs H & W), and greater inotrope requirements (p < 0.05 vs H). Non-white children had higher proportions of public insurance. VAD utilization at listing was: B-11%, H-8%, W-8% (p = 0.001 for B vs H & W). VAD at transplant was: B-24%, H-21%, W-19% (p = 0.001 for B vs H). At transplant, all VAD patients had comparable clinical status (functional limitation, renal/hepatic dysfunction, inotropes, mechanical ventilation; all p > 0.05 between groups). Following VAD, hospital outcomes and one-year PTS were equivalent but long-term PTS was significantly worse among non-whites-(p < 0.01 for W vs B & H). On multivariable analysis, black race independently predicted mortality (hazard ratio 1.67 [95% confidence interval 1.22-2.28]) while white race was protective (0.54 [0.40-0.74]).

CONCLUSIONS

Pediatric VAD use is, seemingly, equitable; the most ill patients receive the most VADs. Despite similar pretransplant and early post-transplant benefits, non-white children experience inferior overall PTS after VAD BTT.

Lung Transplantation for Bronchopulmonary Dysplasia

BACKGROUND

Patients with bronchopulmonary dysplasia (BPD) have poor respiratory trajectories and are at increased risk of lung function decline with age. Lung transplant (LTx) is a possible treatment option for this growing patient population, but little has been published on LTx in this patient group.

RESEARCH QUESTION

What are the characteristics of patients with BPD who are listed for LTx? How do waitlist and post-LTx outcomes for BPD compare with LTx for other diagnoses?

STUDY DESIGN AND METHODS

The United Network for Organ Sharing (UNOS) registry was queried for patients of all ages listed for or who underwent LTx (2000-2020). Descriptive analysis, waitlist outcomes, and post-LTx survival at 1, 5, and 10 years were assessed comparing patients with BPD vs LTx patients with other diagnoses. Post-LTx survival for patients with BPD born in the pre-surfactant era (pre-SE, before 1990) and those born in the post-surfactant era (post-SE) was compared. Propensity score matching was performed to control for the risk factors and match patients with BPD with other LTx patients on a 1:1 ratio.

RESULTS

BPD was reported in 65 patients, of whom 32 (49.2%) underwent LTx. Patients with BPD at listing were younger than those with other diagnoses (median age, 21 [interquartile range, 5-31] years vs 57 [45-63] years; P < .001), and more were likely to receive mechanical ventilation at listing (23% vs 3.7%; P < .001). Patients with BPD had an FEV1 of 17% compared with 34% predicted in other patients (P = .002). Patients with BPD had an overall similar post-LTx survival compared with patients with other diagnoses (P = .106), even following propensity score matching (P = .41).

INTERPRETATION

LTx for BPD has increased over the last 20 years. Patients with BPD have similar post-LTx outcomes compared with those of other patient populations in the modern era. Thus, LTx could be considered for patients with BPD experiencing progressive respiratory deterioration.

Impact of Weight on Ventricular Assist Device Outcomes in Dilated Cardiomyopathy Patients in Pediatric Centers: An ACTION Registry Study

Ventricular assist device (VAD) options vary for children in different weight groups. This study evaluates contemporary device usage and outcomes for children based on weight. Data from the Advanced Cardiac Therapies Improving Outcomes Network (ACTION) registry were examined for patients with dilated cardiomyopathy (DCM) in 4 weight cohorts: <8 kg, 8-20 kg, 21-40 kg, and >40 kg, for devices implanted 3/2013-10/2020. Adverse event rates and ultimate outcome (deceased, alive on device, transplanted, or ventricular recovery) were analyzed. 222 DCM patients were identified with 24% in cohort 1, 23% in cohort 2, 15% in cohort 3, and 38% in cohort 4. Of 272 total implants, paracorporeal pulsatile devices were most common (95%) in cohorts 1 and 2 and intracorporeal continuous devices (81%) in cohorts 3 and 4. Stroke was noted in 17%, 12%, 6%, and 4% of cohorts, respectively (Cohort 1 vs. 4 and 2 vs. 4 - p = 0.01; other comparisons - not significant). Incidences of major bleeding, device malfunction, and infection was not different. All cohorts had >90% positive outcomes. Stroke incidence was higher in smaller cohorts, but other outcomes were similar. Positive outcomes were attained in over 90% across all weight groups, demonstrating excellent outcomes using current VADs in this DCM population.

Isosorbide DiNitrate Effect on Hemodynamic Profile, Liver Stiffness, and Exercise Tolerance in Fontan Circulation (The NEET Clinical Trial)

After Fontan operation, decreased venous capacitance and venoconstriction are adaptive mechanisms to maintain venous return and cardiac output. The consequent higher venous pressure may adversely impact end-organ function, exercise capacity and result in worse clinical outcomes. This pilot study evaluated the safety and effect of isosorbide dinitrate (ISDN), a venodilator, on exercise capacity, peripheral venous pressure (PVP), and liver stiffness in patients with Fontan circulation. In this prospective single-arm trial, 15 individuals with Fontan circulation were evaluated at baseline and after 4 weeks of therapeutic treatment with ISDN. Primary aims were to assess the safety of ISDN and the effect on maximal exercise. We also aimed to evaluate the effect of ISDN on ultrasound-assessed liver stiffness, markers of submaximal exercise, and PVP at rest and peak exercise. Repeated measures t-tests were used to assess change in variables of interest in response to ISDN. Mean age was 23.5 ± 9.2 years (range 11.2-39.0 years), and 10/15 (67%) were male. There was no statistically significant change in peak VO₂ (1401 ± 428 to 1428 ± 436 mL/min, p = 0.128), but VO₂ at the anaerobic threshold increased (1087 ± 313 to 1115 ± 302 mL/min, p = 0.03). ISDN was also associated with a lower peak exercise PVP (22.5 ± 4.5 to 20.6 ± 3.0 mmHg, p = 0.015). Liver stiffness was lower with ISDN, though the difference was not statistically significant (2.3 ± 0.4 to 2.1 ± 0.5 m/s, p = 0.079). Of the patients completing the trial, mild headache was common (67%), but there were no major adverse events. Treatment with ISDN for 4 weeks is well-tolerated in patients with a Fontan circulation. ISDN is associated with an increase in VO₂ at anaerobic threshold, lower peak PVP, and a trend toward lower liver stiffness. Larger, longer duration studies will be necessary to define the impact of ISDN on clinical outcomes in the Fontan circulation.Clinical Trial Registration: URL: https://clinicaltrials.gov . Unique identifier: NCT04297241.

Cardiac Tamponade Related to a Large Pericardial Mass in a Female with Juvenile Idiopathic Arthritis

We report the case of a young female with juvenile idiopathic arthritis presenting with cardiac tamponade secondary to an unusual pericardial mass. Pericardial masses are typically incidental findings. In rare circumstances they can cause compressive physiology warranting urgent intervention. She required surgical excision which revealed a pericardial cyst encapsulating a chronic solidified hematoma. Though certain inflammatory disorders are associated with myopericarditis, to our knowledge this is the first reported case of a pericardial mass in a well-controlled young patient. We theorize her immunosuppressant therapy resulted in hemorrhage into a pre-existing pericardial cyst, suggesting the need for further follow-up in those on adalimumab therapy.

Absolute Versus Relative Near-Infrared Spectroscopy in Pediatric Cardiac Patients

OBJECTIVES

Near-infrared spectroscopy (NIRS) has been increasingly accepted as a noninvasive marker of regional tissue oxygenation despite concerns of imprecision and wide limits of agreement (LOA) with invasive oximetry. New generation absolute monitors may have improved accuracy compared with trend monitors. We sought to compare the concordance with invasive venous oximetry of a new generation absolute NIRS-oximeter (FORESIGHT ELITE; CASMED, Branford, CT) with a modern widely used trend monitor (INVOS 5100C; Medtronic, Minneapolis, MN).

DESIGN

Prospective single-center study.

SETTING

Tertiary pediatric heart center.

PATIENTS

Children undergoing elective cardiac catheterization under general anesthesia. Time-paired venous oximetry samples (jugular and renal) were compared with NIRS-derived oximetry by two monitors using regression and Bland-Altman analysis.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We enrolled 36 children (19 female, 10 cyanotic) with median age 4.1 years (25-75%, 2.5-7.8 yr) and weight 16.7 kg (12.3-29.1 kg). The absolute difference between NIRS-derived and invasive jugular oximetry was less than 10% in 67% of occasions for both monitors. Correlation was fair (Spearman rs = 0.40; p = 0.001) for the FORESIGHT ELITE and poor ( rs = 0.06; p = 0.71) for the INVOS 5100C. Bias and LOA were +6.7% (+22%, -9%) versus +1.3% (LOA = +24%, -21%), respectively. The absolute difference between NIRS-derived and invasive renal oximetry was less than 10% in 80% of occasions with moderate correlation ( rs = 0.57; p < 0.001) for the FORESIGHT ELITE and in 61% of occasions with moderate correlation ( rs = 0.58; p < 0.001) for the INVOS 5100C; bias and LOA were +3.6% (+19%, -12%) and -1.4 % (+27%, -30%), respectively. NIRS correlation with renal venous oximetry was worse for cyanotic versus noncyanotic patients ( p = 0.02).

CONCLUSIONS

Concordance and LOA of NIRS-derived oximetry with invasive venous oximetry in the cerebral and renal vascular beds was suboptimal for clinical decision-making. Cyanosis adversely affected NIRS performance in the renal site.

Heart transplant offers are less likely to be accepted on weekends, holidays, and conferences

BACKGROUND

The existence of a "weekend effect" in heart transplantation (HTx) is understudied. The present study sought to determine whether the odds of (HTx) offer acceptance differed for adult and pediatric candidates depending upon the day on which the offer occurred.

METHODS

United Network for Organ Sharing data were used to identify all HTx offers to adult (listing age ≥18) and pediatric candidates from 2000-2019. Odds of offer acceptance were studied, comparing weekends, holidays, and conferences (Society of Thoracic Surgeons [STS], American Association for Thoracic Surgery [AATS], International Society for Heart and Lung Transplantation [ISHLT]) to "baseline" (all other days). Multivariable binary logistic regression analyses were performed to determine independent predictors of offer nonacceptance, controlling for the impacts of program transplant volume, region, and candidate characteristics.

RESULTS

A total of 323,953 offers occurred - 298,405 to adults and 25,548 to pediatric candidates. Clinically significant differences did not exist in donor or candidate characteristics between baseline or other events. The number of offers per day was stable throughout the year for both adults (p = 0.191) and pediatrics (p = 0.976). In adults, independently lower odds of acceptance existed on weekends (OR 0.88 [95% CI 0.84-0.92]), conferences in aggregate (0.86 [0.77-0.95]), and holidays in aggregate (0.81 [0.72-0.91]). In children, independently lower odds of acceptance were seen on weekends (0.88 [0.79-0.98]), during STS (0.46 [0.25-0.83], and during Christmas (0.32 [0.14-0.76]).

CONCLUSIONS

The day on which a HTx offer occurs significantly impacts its likelihood of acceptance. Further work can determine the impacts of human behavior or resource distribution, but knowledge of this phenomenon can inform efforts to ensure ideal organ allocation throughout the year.

Are Parent Discharge Readiness Scores Effective for the Congenital Heart Disease Patients After Cardiac Surgery?

OBJECTIVE

To assess discharge readiness and clinical engagement post-discharge in familes of children undergoing congenital heart surgery (CHS).

STUDY DESIGN

This prospective cross-sectional study was performed at a major tertiary pediatric cardiac referral center. Eligible parents and caregivers completed a discharge readiness tool, the Readiness for Hospital Discharge Scale for Parents of Hospitalized Children (PedRHDS), via online survey on the day of discharge. Clinical engagement data included subsequent phone calls, clinic visits, emergency department (ED) visits, and hospital readmissions. PedRHDS scores were measured as follows: Very High (9-10), High (8-8.9), Moderate (7-7.9), and Low (<7). Descriptive statistics were used to describe demographic data.

RESULTS

128 families enrolled between April and December 2021. Parent discharge readiness scores ranged from 'High' to 'Very High.' Families with lower socioeconomic status and younger patients (especially single ventricle infants or "interstage") had a higher proportion of clinic visits, ED visits, and hospital readmissions within 30-days post-discharge compared with other groups.

CONCLUSIONS

Discharge readiness scores were not associated with clinical engagement. We identified vulnerable populations as evidenced by a higher frequency of clinical engagement in the immediate post-operative period, particularly younger patients and first time surgeries. While these visits may be appropriate, novel programs could enhance education and emotional support to prevent delay in seeking care or creating excessive stress and anxiety after discharge.

Contemporary Outcomes of Heart Transplantation in Children with Heterotaxy Syndrome: Sub-Optimal Pre-Transplant Optimization Translates into Early Post-Transplant Mortality

Patients with heterotaxy syndrome and congenital heart disease (CHD) experience inferior cardiac surgical outcomes. Heart transplantation outcomes are understudied, however, particularly compared to non-CHD patients. Data from UNOS and PHIS were used to identify 4803 children (< 18 years) undergoing first-time heart transplant between 2003 and 2022 with diagnoses of heterotaxy (n = 278), other-CHD (n = 2236), and non-CHD cardiomyopathy (n = 2289). Heterotaxy patients were older (median 5 yr) and heavier (median 17 kg) at transplant than other-CHD (median 2 yr and 12 kg), and younger and lighter than cardiomyopathy (median 7 yr and 24 kg) (all p < 0.001). UNOS status 1A/1 at listing was not different between groups (65-67%; p = 0.683). At transplant, heterotaxy and other-CHD patients had similar rates of renal dysfunction (12 and 17%), inotropes (10% and 11%), and ventilator-dependence (19 and 18%). Compared to cardiomyopathy, heterotaxy patients had comparable renal dysfunction (9%, p = 0.058) and inotropes (46%, p = 0.097) but more hepatic dysfunction (17%, p < 0.001) and ventilator-dependence (12%, p = 0.003). Rates of ventricular assist device (VAD) were: heterotaxy-10%, other-CHD-11% (p = 0.839 vs. heterotaxy), cardiomyopathy-37% (p < 0.001 vs. heterotaxy). The 1-year incidence of acute rejection post-transplant was comparable between heterotaxy and others (p > 0.05). While overall post-transplant survival was significantly worse for heterotaxy than others (p < 0.05 vs. both), conditional 1-year survival was comparable (p > 0.3 vs. both). Children with heterotaxy syndrome experience inferior post-heart transplant survival, although early mortality appears to influence this trend, with 1-year survivors having equivalent outcomes. Given similar pre-transplant clinical status to others, heterotaxy patients are potentially under risk-stratified. Increased VAD utilization and pre-transplant end-organ function optimization may portend improved outcomes.

Changing racial and ethnic differences for lung transplantation in cystic fibrosis

BACKGROUND

CFTR modulators, especially (elexacaftor/tezacaftor/ivacaftor), have positively impacted the CF population and quickly decreased LTx numbers. However, no study has investigated if this reduction is universal across all races/ethnicities.

METHODS

Using the UNOS Registry, we explored the frequency/proportions of LTx in WNH and NW (Black, non-Hispanic/Hispanic-Latino/Asian-non Hispanic/American Indian-Alaskan Native-non-Hispanic/Native Hawaiian/Other Pacific Islander-non-Hispanic/Multiracial) in children and adults with CF in the US.

RESULTS

Between 1990 and 2019, the annual mean (±SD) number of LTxs for children with CF was 23.2 (±7.7) compared to 5 in 2020 (p < .001) and in 2021 (p < .001). In adults from 1990 to 2019, the mean (±SD) number of LTxs performed was 144.9 (±73.5), which was significantly higher than 2020 (n = 73; p < .001) and 2021 (n = 45; p < .001). Comparing 1990-2019 to post-2019, the proportion of LTxs performed in both children and adults with CF has decreased from 50.5% (696/1378) to 16.4% (9/55) and from 12.1% (4773/39542) to 2.4% (118/5004), respectively. In WNH pediatric patients, the difference in the percentage of all LTx made up by CF patients between the two eras was 41.2% compared to NW patients where the difference was 11%. Similarly in adults, the difference between the two eras was 10.4% in WNH and 2.4% in NW patients.

CONCLUSIONS

The recent reduction in LTx for the CF population has had less impact on the NW population in the US, so the continuation of optimal referrals for this group is needed.

Considerations for Advanced Heart Failure Consultation in Individuals With Fontan Circulation: Recommendations From ACTION

Individuals with Fontan circulation are at risk of late mortality from both cardiac and noncardiac causes. Despite the known risk of mortality, referral indications for advanced heart failure care vary between centers, and many individuals die from Fontan circulation-related complications either after late consideration for advanced heart failure therapies or having never seen a heart failure specialist. There is a critical need for guidelines to direct appropriately timed referral for advanced heart failure consultation. The Advanced Cardiac Therapies Improving Outcomes Network (ACTION) Fontan Committee has developed recommended thresholds for advanced heart failure referral to guide primary cardiologists. These recommendations are divided into 4 categories of clinical Fontan circulatory dysfunction including (1) cardiac/systemic ventricular dysfunction, (2) Fontan pathway dysfunction, (3) lymphatic dysfunction, and (4) extracardiac dysfunction.

Echocardiography Provides a Reliable Estimate of Total Cardiac Volume for Pediatric Heart Transplantation

BACKGROUND

Donor-to-recipient size matching for heart transplantation typically involves comparing donor and recipient body weight; however, weight is not linearly related to cardiac size. Attention has shifted toward the use of computed tomography- (CT-) derived total cardiac volume (TCV), that is, CT-TCV, to compare donor and recipient heart organ size. At this time, TCV size matching is near impossible for most centers due to logistical limitations. To overcome this impediment, echocardiogram-derived TCV (ECHO-TCV) is an attractive, alternative option to estimate CT-TCV. The goal of this study is to test whether ECHO-TCV is an accurate and reliable surrogate for TCV measurement compared with the gold standard CT-TCV.

METHODS

ECHO-TCV and CT-TCV were measured in a cohort spanning the neonatal to young adult age range with the intention to simulate the pediatric heart transplant donor pool. ECHO-TCV was measured using a modified Simpson's summation-of-discs method from the apical 4-chamber (A4C) view. The gold standard of CT-TCV was measured from CT scans using three-dimensional reconstruction software. The relationship between ECHO-TCV and CT-TCV was evaluated and compared with other anthropometric and image-based markers that may predict CT-TCV. Inter-rater reliability of ECHO-TCV was tested among 4 independent observers. Subanalyses were performed to identify imaging views and timing that enable greater accuracy of ECHO-TCV.

RESULTS

Banked imaging data of 136 subjects with both echocardiogram and CT were identified. ECHO-TCV demonstrated a linear relationship to CT-TCV with a Pearson correlation coefficient of r = 0.96 (95% CI, 0.95-0.97; P < .0001) and mean absolute percent error of 8.6%. ECHO-TCV correlated most strongly with CT-TCV in the subset of subjects <4 years of age (n = 33; r = 0.98; 95% CI, 0.96-0.99; P < .0001). The single-score intraclass correlation coefficient across all 4 raters is 0.96 (interquartile range, 0.93-0.98). ECHO-TCV measured from a standard A4C view at end diastole with the atria in the plane of view had the strongest correlation to CT-TCV.

CONCLUSIONS

ECHO-TCV by the A4C view was found to be both an accurate and reliable alternative measurement of CT-TCV and is derived from readily available donor ECHO images. The ECHO-TCV findings in this study make the ECHO method an attractive means of direct donor-to-recipient TCV size matching in pediatric heart transplantation.

Female donor hearts can improve survival for male pediatric heart transplant recipients

BACKGROUND

Both gender- and weight-matching between donor and recipient are thought to impact survival in pediatric heart transplantation, with clinical dogma holding that male donor hearts and "ideal" weight-matching yield superior survival. The composite impacts of gender and weight on post-transplant survival (PTS) are understudied.

METHODS

All pediatric (age <18) heart recipients between 1989 and 2021 with the complete recipient and donor gender and weight data were identified in the United Network for Organ Sharing database. Patients were grouped by recipient-donor gender (M & F) and donor-to-recipient weight ratio (DRWR; undersized [<0.8], ideal-sized [0.8-1.5], oversized [>1.5]).

RESULTS

A total of 10 697 patients were identified. Among male recipients, PTS was greatest with oversized DRWR from either male or female donors (median 22.4 and 20.6 years; p < .001 vs. others) and lowest for undersized DRWR from either male or female donors (median 13.4 and 13.2 years; p < .001 vs. others). The majority (64%) of male recipients received ideal-sized DRWR, among which female donor hearts yielded superior survival to males (median 18.9 vs. 17.4 years, p = .014). No differences in PTS existed for female recipients on the basis of gender-match, DRWR, and gender/DRWR together (all p > .1).

CONCLUSIONS

When considered together, gender and DRWR pairings impact PTS in male-but not female-pediatric heart transplant recipients. For males receiving ideal-sized DRWR organs (most common pairing, >60%), male recipients achieve superior survival when female donor hearts are transplanted. These findings suggest that if weight is being used for size-matching, donor gender should also be considered, particularly for male recipients.

Initial multicenter experience with ventricular assist devices in children and young adults with muscular dystrophy: An ACTION registry analysis

PURPOSE

Cardiac disease results in significant morbidity and mortality in patients with muscular dystrophy (MD). Single centers have reported their ventricular assist device (VAD) experience in specific MDs and in limited numbers. This study sought to describe the outcomes associated with VAD therapy in an unselected population across multiple centers.

METHODS

We examined outcomes of patients with MD and dilated cardiomyopathy implanted with a VAD at Advanced Cardiac Therapies Improving Outcomes Network (ACTION) centers from 9/2012 to 9/2020.

RESULTS

A total of 19 VADs were implanted in 18 patients across 12 sites. The majority of patients had dystrophinopathy (66%) and the median age at implant was 17.2 years (range 11.7-29.5). Eleven patients were non-ambulatory (61%) and 6 (33%) were on respiratory support pre-VAD. Five (28%) patients were implanted as a bridge to transplant, 4 of whom survived to transplant. Of 13 patients implanted as bridge to decision or destination therapy, 77% were alive at 1 year and 69% at 2 years. The overall frequencies of positive outcome (transplanted or alive on device) at 1 year and 2 years were 84% and 78%, respectively. Two patients suffered a stroke, 2 developed sepsis, 1 required tracheostomy, and 1 experienced severe right heart failure requiring right-sided VAD.

CONCLUSIONS

This study demonstrates the potential utility of VAD therapies in patients with muscular dystrophy. Further research is needed to further improve outcomes and better determine which patients may benefit most from VAD therapy in terms of survival and quality of life.