Surgically induced aortic coarctation in a neonatal porcine model allows for longitudinal assessment of cardiovascular changes.

Noncritical aortic coarctation (COA) typically presents beyond early childhood with hypertension. Correction of COA does not ensure a return to normal cardiovascular health, but the mechanisms are poorly understood. Therefore, we developed a porcine COA model to study the secondary cardiovascular changes. Eight male neonatal piglets (4 sham, 4 COA) underwent left posterolateral thoracotomy with descending aorta (DAO) mobilization. COA was created via a 1-cm longitudinal DAO incision with suture closure, plication, and placement and an 8-mm external band. All animals had cardiac catheterization at 6 (11-13 kg), 12 (26-31 kg), and 20 (67-70 kg) wk of age. Aortic luminal diameters were similar along the thoracic aorta, except for the COA region [6.4 mm COA vs. 17.3 mm sham at 20 wk (P < 0.001)]. Collateral flow could be seen as early as 6 wk. COA peak systolic pressure gradient was 20 mmHg at 6 wk and persisted through 20 wk increasing to 40 mmHg with dobutamine. Pulse pressures distal to the COA were diminished at 12 and 20 wk. This model addresses many limitations of prior COA models including neonatal creation at an expected anatomic position with intimal injury and vessel sizes similar to humans.NEW & NOTEWORTHY A neonatal model of aortic coarctation was developed in a porcine model using a readily reproducible method of aortic plication and external wrap placement. This model addresses the limitations of existing models including neonatal stenosis creation, appropriate anatomic location of the stenosis, and intimal injury creation and mimics human somatic growth. Pigs met American Heart Association (AHA) criteria for consideration of intervention, and the stenoses were graded as moderate to severe.

Association of Size Matching Using Predicted Heart Mass With Mortality in Heart Transplant Recipients With Obesity or High Pulmonary Vascular Resistance.

Importance: Pretransplant obesity and higher pulmonary vascular resistance (PVR) are risk factors for death after heart transplant. However, it remains unclear whether appropriate donor-to-recipient size matching using predicted heart mass (PHM) is associated with lower risk. Objective: To investigate the association of size matching using PHM with risk of death posttransplant among patients with obesity and/or higher PVR. Design, Setting, and Participants: All adult patients (>18 years) who underwent heart transplant between 2003 and 2022 with available information using the United Network for Organ Sharing cohort database. Multivariable Cox models and multivariable-adjusted spline curves were used to examine the risk of death posttransplant with PHM matching. Data were analyzed from October 2022 to March 2023. Exposure: Recipient's body mass index (BMI) in categories (<18.0 [underweight], 18.1-24.9 [normal weight, reference], 25.0-29.9 [overweight], 30.0-34.9 [obese 1], 35-39.9 [obese 2], and ≥40.0 [obese 3]) and recipient's pretransplant PVR in categories of less than 4 (29 061 participants), 4 to 6 (2842 participants), and more than 6 Wood units (968 participants); and less than 3 (24 950 participants), 3 to 5 (6115 participants), and 5 or more (1806 participants) Wood units. Main Outcome: All-cause death posttransplant on follow-up. Results: The mean (SD) age of the cohort of 37 712 was 52.8 (12.8) years, 27 976 (74%) were male, 25 342 were non-Hispanic White (68.0%), 7664 were Black (20.4%), and 3139 were Hispanic or Latino (8.5%). A total of 12 413 recipients (32.9%) had a normal BMI, 13 849 (36.7%) had overweight, and 10 814 (28.7%) had obesity. On follow-up (median [IQR] 5.05 [0-19.4] years), 12 785 recipients (3046 female) died. For patients with normal weight, overweight, or obese 2, receiving a PHM-undermatched heart was associated with an increased risk of death (normal weight hazard ratio [HR], 1.20; 95% CI, 1.07-1.34; overweight HR, 1.12; 95% CI, 1.02-1.23; and obese 2 HR, 1.07; 95% CI, 1.01-1.14). Moreover, patients with higher pretransplant PVR who received an undermatched heart had a higher risk of death posttransplant in multivariable-adjusted spline curves in graded fashion until appropriately matched. In contrast, risk of death among patients receiving a PHM-overmatched heart did not differ from the appropriately matched group, including in recipients with an elevated pretransplant PVR. Conclusion and Relevance: In this cohort study, undermatching donor-to-recipient size according to PHM was associated with higher posttransplant mortality, specifically in patients with normal weight, overweight, or class II obesity and in patients with elevated pretransplant PVR. Overmatching donor-to-recipient size was not associated with posttransplant survival.

Systems of Care Factors Should Be Considered in Regionalization of Congenital Cardiac Surgery.

BACKGROUND: Regionalization of care has been proposed to optimize outcomes in congenital cardiac surgery (CCS). We hypothesized that hospital infrastructure and systems of care factors could also be considered in regionalization efforts. METHODS: Observed-to-expected (O/E) mortality ratio and hospital volumes were obtained between 2015 and 2018 from public reporting data. Using a resource dependence framework, we examined factors obtained from American Hospital Association, Children's Hospital Association, and hospital websites. Linear regression models were estimated with volume only, then with hospital factors, stratified by procedural complexity. Robust regression models were reestimated to assess the impact of outliers. RESULTS: We found wide variation in the volume of congenital cardiac surgeries performed (89-3920) and in the surgical outcomes (O/E ratio range, 0.3-3.1). Six outlier hospitals performed few high-complexity cases with high mortality. Univariate analysis including all cases indicated that higher volume predicted lower O/E ratio (ß = -0.02; SE = 0.008; P = .011). However, this effect was driven by the most complex cases. Models stratified by The Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery category show that volume is a significant predictor only in category 5 cases (ß = -1.707; SE = 0.663; P = .012). Robust univariate regression accounting for outliers found no effect of volume on O/E ratio (ß = 0.005; SE = 0.002; P = .975). Elimination of outliers through robust multivariate regression decreased the volume-outcome relationship and found a modest relationship between health plan ownership and outcomes. CONCLUSIONS: Systems of care factors should be considered in addition to volume in designing regionalization in CCS. Patient-level data sets will better define these factors.

Nicardipine Is a Safe, Efficacious, and Cost-Effective Antihypertensive for Neonates and Young Infants Undergoing Cardiac Surgery.

OBJECTIVE: The use of nicardipine in congenital cardiac surgery has been guarded given the calcium sensitivity of immature myocardium and paucity of clinical data. Reports of nicardipine use have excluded neonates with single ventricles. The goal of this study was to compare the use of nicardipine and sodium nitroprusside for postoperative blood pressure control in young patients recovering from cardiac surgery. METHODS: All neonates (<30 days) and young infants (31-180 days) who received either sodium nitroprusside or nicardipine as first-line therapy for blood pressure control were retrospectively reviewed. Some patients had multiple index operations and each index operation was counted separately regarding treatment with sodium nitroprusside or nicardipine. RESULTS: A total of 59 patients underwent 70 procedures (24 as neonates and 46 as infants). Nicardipine was administered as initial therapy following 33 procedures (n = 28 patients), and sodium nitroprusside was administered as initial therapy following 37 index procedures (n = 31 patients). The duration of treatment was longer (P = .025) when sodium nitroprusside was the initial treatment. Five (15%) patients that received nicardipine required a second blood pressure management agent, and seven (19%) patients that received sodium nitroprusside required a second agent (P = .66). No adverse events related to titratable antihypertensive therapy were recorded in any treatment group. The use of nicardipine resulted in significant medication cost reduction. Based on average wholesale price, patient costs for sodium nitroprusside use were $182,952 ($5,544/pt), while costs for nicardipine were only $24,960 ($780/pt). CONCLUSIONS: Nicardipine can be safely used as a first-line antihypertensive in infants. The use of nicardipine as initial antihypertensive therapy rather than sodium nitroprusside can lead to a significant reduction in medication costs without jeopardizing clinical outcomes.

Is Porcine Small Intestinal Submucosal Extracellular Matrix (ECM) a Suitable Material for Right Ventricular Outflow Tract Reconstruction in Association With Pulmonary Valve Replacement?

Pulmonary valve replacement (PVR) with right ventricular outflow tract (RVOT) reconstruction is a common congenital cardiac operation. Porcine submucosal intestinal-derived extracellular matrix (ECM) patches have been used for RVOT reconstruction. We present 2 adult patients with Tetralogy of Fallot who underwent PVR with RVOT reconstruction utilizing ECM. Both cases required reoperation due to patch dehiscence causing a large paravalvular leak. One patient also had a pseudoaneurysm associated with ECM dehiscence. There may be a propensity for ECM dehiscence in this application and, based on these cases, we recommend avoidance of ECM in RVOT reconstruction with PVR. PVR patients repaired with ECM should be monitored for this complication.

The Use of STS Public Reporting to Guide Referrals in Congenital Heart Surgery: Results of a Survey.

BACKGROUND: The Society of Thoracic Surgeons (STS) public reporting in congenital heart surgery has received considerable attention; however, it is unclear how pediatric cardiac providers use these data to guide surgical referrals. METHODS: We surveyed members of the American Academy of Pediatrics Section on Cardiology and Cardiac Surgery and PediHeartNet members regarding use of STS public reporting. RESULTS: There were 155 respondents (90% cardiologist, 7% surgeons) from approximately 800 solicitations (∼19% response rate). While most (83%) felt that STS public reporting is important, 60% are unsure of its accuracy and only 37% find it useful in practice. Most (71%) believe STS public reporting leads to risk aversion. Overall, 92% answered that STS public reporting rarely or never overrides other factors determining referrals. Compared with smaller centers (<300 cases/year), providers in larger centers were more likely to report that STS public reporting data never overrides other factors determining referrals (54% vs 32%, P = .03). Providers using STS public reporting to guide referrals (14% overall) trust the system's accuracy (P = .03) and believe it presents useful outcomes (P < .01). There was no correlation between use of STS public reporting to guide referrals and practice size, type, location, time in practice, surgical center affiliation, or center volume. CONCLUSIONS: Providers believe that public reporting of outcomes is important; however, most do not use the data to guide surgical referrals. Understanding these limitations of the current STS public reporting may enable change and increased usefulness for providers.

Unconventional use of total artificial heart in a patient with severe, destructive prosthetic valve endocarditis.

Here, we report the case of a patient who presented to our institution with severe, destructive, and unreconstructable prosthetic valve endocarditis which required the planned implantation of a total artificial heart (TAH) to function as a bridge to cardiac transplantation. The use of TAH in this fashion has been infrequently reported in the literature. This case highlights the importance of a thoughtful, preoperative multidisciplinary approach to these complex patients to provide the most appropriate and life-saving care.

National Trends in Heart Donor Usage Rates: Are We Efficiently Transplanting More Hearts?

Background It is unclear whether the recent increase in the number of heart transplants performed annually in the United States is only because of higher availability of donors and if it affected recipients' survival. Methods and Results We examined characteristics of donors and recipients from 2008 to 2012 (n=11 654) and 2013 to 2017 (n=14 556) and compared them with 2003 to 2007 (n=10 869). Cox models examined 30-day and 1-year risk of recipients' death post transplant. From 2013 to 2017, there was an increase in the number of transplanted hearts and number of donor offers but an overall decline in the ratio of hearts transplanted to available donors. Donors between 2013 and 2017 were older, heavier, more hypertensive, diabetic, and likely to have abused illicit drugs compared with previous years. Drug overdose and hepatitis C positive donors were additional contributors to donor risk in recent years. In Cox models, risk of death post transplant between 2013 and 2017 was 15% lower at 30 days (hazard ratio [HR] 0.85; 95% CI, 0.74-0.98) and 21% lower at 1 year (HR, 0.79; 95% CI, 0.73-0.87) and between 2008 and 2012 was 9% lower at 30 days (HR, 0.91; 95% CI, 0.79-1.05) and 14% lower at 1 year (HR, 0.86; 95% CI, 0.79-0.94) compared with 2003 to 2007. Conclusions Despite a substantial increase in heart donor offers in recent years, the ratio of transplants performed to available donors has decreased. Even though hearts from donors who are older, more hypertensive, and have diabetes mellitus are being used, overall recipient survival continues to improve. Broader acceptance of drug overdose and hepatitis C positive donors may increase the number and percentage of heart transplants further without jeopardizing short-term outcomes.

Survival after orthotopic heart transplantation in patients with BMI > = 35 with and without diabetes.

BACKGROUND: Orthotopic heart transplant (OHT) recipients with a body mass index (BMI) > = 35 have worse survival than those with a BMI < 35. Diabetes is a risk factor for mortality. We evaluated the impact of diabetes on mortality rates after OHT in patients with a BMI > 35. METHODS: Patients > 18 years who underwent OHT 2008-2017 with a BMI > = 35 were identified in the United Network for Organ Sharing (UNOS) database. Recipient and donor characteristics were compared. A Kaplan Meier analysis was performed. A multivariable Cox proportional hazards model examined the relationship between diabetes and survival. The equivalence of survival outcomes was examined by an unadjusted Cox proportional hazards model and the two one-sided test procedure, using a pre-specified equivalence region. RESULTS: Patients with diabetes were older, had a higher creatinine, lower bilirubin, fewer months on the waitlist, and the donor was less likely to be on inotropes. Kaplan-Meier analysis showed no difference in patient survival. Recipient factors associated with an increased risk of death were increasing bilirubin and machine ventilation. Increasing ischemic time resulted in an increased hazard of death. Long-term survival outcomes were equivalent. CONCLUSIONS: In OHT recipients with a BMI > 35, there is no statistical difference in longterm survival in recipients with or without diabetes. These results encourage continued consideration for OHT in patients BMI > 35 with coexisting diabetes.

Case report: a step-wise management of concurrent presentation of congenital single lung and aberrant right subclavian artery in an infant girl.

INTRODUCTION: Congenital single lung (CSL) is a rare condition, and symptomatic patients often present with respiratory distress or recurrent respiratory infection due to mediastinal shift causing vascular or airway compression. Aberrant right subclavian artery (ARSA) is another rare congenital anomality that can lead to tracheal or esophageal compressions. There is only one other case of concurrent presentation of CSL and ARSA reported, which presented unique challenge in surgical management of our patient. Here we present a step-wise, multidisciplinary approach to manage symptomatic CSL and ARSA. CASE PRESENTATION: An infant girl with a prenatal diagnosis of CSL developed worsening stridor and several episodes of respiratory illnesses at 11 months old. Cross-sectional imaging and bronchoscopic evaluation showed moderate to severe distal tracheomalacia with anterior and posterior tracheal compression resulting from severe mediastinal rotation secondary to right-sided CSL. It was determined that her tracheal compression was mainly caused by her aortic arch wrapping around the trachea, with possible additional posterior compression of the esophagus by the ARSA. She first underwent intrathoracic tissue expander placement, which resulted in immediate improvement of tracheal compression. Two days later, she developed symptoms of dysphagia lusoria due to increased posterior compression of her esophagus by the ARSA. She underwent transposition of ARSA to the right common carotid with immediate resolution of dysphagia lusoria. As the patient grew, additional saline was added to the tissue expander due to recurrence in compressive symptoms. CONCLUSIONS: Concurrent presentation of CSL and ARSA is extremely rare. Asymptomatic CSL and ARSA do not require surgical interventions. However, if symptomatic, it is crucial to involve a multidisciplinary team for surgical planning and to take a step-wise approach as we were able to recognize and address both tracheomalacia and dysphagia lusoria in our patient promptly.

Multimodal Cardiopulmonary Bypass Skills Assessment Within a High-Fidelity Simulation Environment.

BACKGROUND: A high-fidelity simulator that uses a perfused porcine heart, cannulae, and tubing has been demonstrated to be a useful training adjunct. We hypothesized that multimodal assessment of cardiopulmonary bypass (CPB) skills within this high-fidelity simulated environment could discern expert from trainee performance. METHODS: Three traditional fellows (postgraduate year 6-8) and 3 attending surgeons each performed 3 aortic cannulations. The third sequence included venous cannulation, commencement of CPB, and placement of a cardioplegia catheter and aortic cross-clamp. Performance across 20 cognitive and 21 technical domains was evaluated. Surgeon and assistant hand movements and economy of motion were assessed by electromagnetic motion sensors worn under sterile gloves. RESULTS: Analysis showed a significant difference in cognitive (6.7 ± 2.3 vs 4.6 ± 2.7, P = .03) but not technical (6.2 ± 2.5 vs 5.8 ± 2.2, P = .7) scores favoring the experts. In addition, experts showed higher efficiency by spending 64 ± 14 seconds to construct a nonpledgeted aortic purse-string suture and secure it with a Rummel, while trainees spent 82 ± 30 seconds to complete this task (P = .03). Motion analysis revealed similar path lengths between experts and trainees for cannulation and CPB but significantly shorter path lengths for experts in cross-clamp (47.5 ± 15.5 m vs 91.9 ± 20.3 m, P = .04). CONCLUSIONS: Multimodal assessment using cognitive, technical, and motion analysis of basic CPB tasks using a high-fidelity simulation environment is a valid system to measure performance and discriminate experts from trainees. This construct may allow for development of "competence thresholds" with important implications for training and certification in cardiothoracic surgery.

Pulmonary artery and lung parenchymal growth following early versus delayed stent interventions in a swine pulmonary artery stenosis model.

OBJECTIVES: Compare lung parenchymal and pulmonary artery (PA) growth and hemodynamics following early and delayed PA stent interventions for treatment of unilateral branch PA stenosis (PAS) in swine. BACKGROUND: How the pulmonary circulation remodels in response to different durations of hypoperfusion and how much growth and function can be recovered with catheter directed interventions at differing time periods of lung development is not understood. METHODS: A total of 18 swine were assigned to four groups: Sham (n = 4), untreated left PAS (LPAS) (n = 4), early intervention (EI) (n = 5), and delayed intervention (DI) (n = 5). EI had left pulmonary artery (LPA) stenting at 5 weeks (6 kg) with redilation at 10 weeks. DI had stenting at 10 weeks. All underwent right heart catheterization, computed tomography, magnetic resonance imaging, and histology at 20 weeks (55 kg). RESULTS: EI decreased the extent of histologic changes in the left lung as DI had marked alveolar septal and bronchovascular abnormalities (p = .05 and p < .05 vs. sham) that were less prevalent in EI. EI also increased left lung volumes and alveolar counts compared to DI. EI and DI equally restored LPA pulsatility, R heart pressures, and distal LPA growth. EI and DI improved, but did not normalize LPA stenosis diameter (LPA/DAo ratio: Sham 1.27 ± 0.11 mm/mm, DI 0.88 ± 0.10 mm/mm, EI 1.01 ± 0.09 mm/mm) and pulmonary blood flow distributions (LPA-flow%: Sham 52 ± 5%, LPAS 7 ± 2%, DI 44 ± 3%, EI 40 ± 2%). CONCLUSION: In this surgically created PAS model, EI was associated with improved lung parenchymal development compared to DI. Longer durations of L lung hypoperfusion did not detrimentally affect PA growth and R heart hemodynamics. Functional and anatomical discrepancies persist despite successful stent interventions that warrant additional investigation.