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.

Distinct hypertrophic cardiomyopathy genotypes result in convergent sarcomeric proteoform profiles revealed by top-down proteomics.

Hypertrophic cardiomyopathy (HCM) is the most common heritable heart disease. Although the genetic cause of HCM has been linked to mutations in genes encoding sarcomeric proteins, the ability to predict clinical outcomes based on specific mutations in HCM patients is limited. Moreover, how mutations in different sarcomeric proteins can result in highly similar clinical phenotypes remains unknown. Posttranslational modifications (PTMs) and alternative splicing regulate the function of sarcomeric proteins; hence, it is critical to study HCM at the level of proteoforms to gain insights into the mechanisms underlying HCM. Herein, we employed high-resolution mass spectrometry-based top-down proteomics to comprehensively characterize sarcomeric proteoforms in septal myectomy tissues from HCM patients exhibiting severe outflow track obstruction (n = 16) compared to nonfailing donor hearts (n = 16). We observed a complex landscape of sarcomeric proteoforms arising from combinatorial PTMs, alternative splicing, and genetic variation in HCM. A coordinated decrease of phosphorylation in important myofilament and Z-disk proteins with a linear correlation suggests PTM cross-talk in the sarcomere and dysregulation of protein kinase A pathways in HCM. Strikingly, we discovered that the sarcomeric proteoform alterations in the myocardium of HCM patients undergoing septal myectomy were remarkably consistent, regardless of the underlying HCM-causing mutations. This study suggests that the manifestation of severe HCM coalesces at the proteoform level despite distinct genotype, which underscores the importance of molecular characterization of HCM phenotype and presents an opportunity to identify broad-spectrum treatments to mitigate the most severe manifestations of this genetically heterogenous disease.

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.

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.

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.

Long-term discontinuation of warfarin in a patient with HeartMate 3 left ventricular assist device without complication.

A 38-year-old woman with peripartum cardiomyopathy underwent placement of a HeartMate 3 (HM3) left ventricular assist device (LVAD). Postoperatively, she refused warfarin therapy and was maintained on aspirin monotherapy for 19 months. She did not experience thrombotic or thromboembolic complications associated with lack of oral vitamin K antagonist anticoagulation. Our patient represents the longest reported duration of a patient with HM3 LVAD maintained without warfarin without evidence of thrombotic or thromboembolic events.

A unique indication for the senning procedure: Atrioventricular discordance with ventriculoarterial concordance.

OBJECTIVE: We describe experience treating a patient with atrioventricular (AV) discordance with ventriculoarterial (VA) concordance, ventricular septal defect (VSD), and situs inversus. This is a rare congenital lesion in which closing the VSD would septate D-transposition physiology and performing an arterial switch and VSD closure would produce congenitally corrected transposition of the great arteries physiology. As such, it is the only lesion for which an isolated atrial switch (and VSD closure) remains the preferred correction. CASE: A term baby girl born with AV discordance/VA concordance, a large VSD, and situs inversus totalis was palliated with atrial septostomy on day of life 3 to allow for optimal mixing and pulmonary artery banding during the 6th week of life to control symptoms of pulmonary overcirculation and protect the pulmonary vasculature. At 8 months of age, she underwent complete repair with a Senning atrial switch procedure, VSD closure, and pulmonary artery debanding with pulmonary arterioplasty. RESULTS: The patient underwent corrective surgery with patch closure of the VSD, and the Senning atrial switch procedure resulting in a total anatomic correction. The patient was discharged on postoperative day 6 and is clinically doing well 12 months later. Follow-up transthoracic echocardiogram shows no pulmonary venous baffle obstruction, mild systemic venous baffle obstruction, and moderate pulmonary stenosis/pulmonary insufficiency. CONCLUSION: The isolated atrial switch is rarely employed as its outcomes are inferior to the arterial switch operation in the setting of the dextro-transposition of the great arteries. However, it remains the procedure of choice for AV discordance with VA concordance as it leads to physiologically corrected biventricular circulation.

Technical Performance Score Predicts Perioperative Outcomes in Complex Congenital Heart Surgery Performed in a Small-to-Medium-Volume Program.

As the quality of surgical outcomes depend on many factors, the development of validated tools to assess the different aspects of complex multidisciplinary teams' performance is crucial. The Technical Performance Score (TPS) has only been validated to correlate with outcomes in large-volume surgical programs. Here we assess the utility of TPS in correlation to perioperative outcomes for complex congenital heart surgeries (CHS) performed in a small-to-medium-volume program. 673 patients underwent CHS from 4/2012 to 12/2017 at our institution. Of those, 122 were STAT 4 and STAT 5. TPS was determined for each STAT 4 and STAT 5 operation using discharge echocardiogram: 1 = optimal, 2 = adequate, 3 = inadequate. Patient outcomes were compared including mortality, length of stay, ventilation times, and adverse events. 69 patients (57%) were neonates, 32 (26%) were infants, 17 (14%) were children, 4 (3%) were adults. TPS class 1 was assigned to 85 (70%) operations, TPS class 2 was assigned to 25 (20%) operations, and TPS class 3 was assigned to 12 (10%) operations. TPS was associated with re-intubation, ICU length of stay, postoperative length of stay, and mortality. TPS did not correlate with unplanned 30-day readmissions, need for reoperation, and inotropic score. Technical performance score was associated with perioperative outcomes and is a useful tool to assess the adequacy of repair for high complexity CHS in a small-to-medium-volume surgical program. TPS should be a part of program review in congenital heart programs of all sizes to identify strategies that may reduce postoperative morbidity and potentially improve long-term outcomes.

Prophylactic Peritoneal Drainage is Associated with Improved Fluid Output after Congenital Heart Surgery.

Infants undergoing congenital heart surgery (CHS) with cardiopulmonary bypass (CPB) are at risk of acute kidney injury (AKI) and fluid overload. We hypothesized that placement of a passive peritoneal drain (PPD) can improve postoperative fluid output in such infants. We analyzed 115 consecutive patients, age birth to 60 days, admitted to the PICU after CHS with CPB between 2012 and 2018. Patients who needed postoperative ECMO were excluded. Linear and logistic regression models compared postoperative fluid balances, diuretics administration, AKI, vasoactive-inotropic scores (VIS), time intubated, and length of stay after adjusting for pre/operative predictors including STAT category, bypass time, age, weight, and open chest status. PPD patients had higher STAT category (p = 0.001), longer CPB times (p = 0.001), and higher VIS on POD 1-3 (p ≤ 0.005 daily). PPD patients also had higher AKI rates (p = 0.01) that did not reach significance in multivariable modeling. There were no postoperative deaths. Postoperative hours of intubation, hospital length of stay, and POD 1-5 fluid intake did not differ between groups. Over POD 1-5, PPD use accounted for 48.8 mL/kg increased fluid output (95% CI [2.2, 95.4], p = 0.043) and 3.41 mg/kg less furosemide administered (95% CI [1.69, 5.14], p < 0.001). No PPD complications were observed. Although PPD placement did not affect end-outcomes, it was used in higher acuity patients. PPD placement is associated with improved fluid output despite lower diuretic administration and may be a useful postoperative fluid management adjunct in some complex CHS patients.

Papillary muscle rupture following routine aortic valve replacement.

A 56-year-old man who underwent routine aortic valve replacement (AVR) for aortic insufficiency suffered a presumed embolic event to a small vessel supplying the posteromedial papillary muscle. This led to papillary muscle rupture, and severe, acute mitral regurgitation requiring emergent mitral valve replacement 6 days postoperatively. Small-vessel coronary embolization outside the setting of infection/endocarditis leading to infarction and papillary muscle rupture following elective AVR has not been previously described in the literature.

Helpful sternal wound vacuum-assisted closure techniques in two open chest situations: Central extracorporeal membrane oxygenation and sternal infection.

BACKGROUND: Dressing open sternal wounds after cardiac surgery can be challenging. In cases where extracorporeal membrane oxygenation (ECMO) is required, the sternum is left open with cannulae traversing the wound, making it difficult to create a water-tight seal and maintain sterility. Patients with a deep sternal infection may also be left with an open sternum between the time of debridement and reconstruction; in such cases, stabilizing the dressing in an ambulatory patient can pose a challenge. METHODS: Two cases are reviewed, each highlighting the solutions to the problems mentioned above. RESULTS: In case 1, a patient with an open sternum and central ECMO, we describe construction of a dressing that achieves air seal and blood seal, and helps maintain the cannulae in a safe, stable position. In case 2, an ambulatory patient, we describe a modification of a recently published "Two Bridge Technique" that provides a stable dressing in three dimensions. CONCLUSION: Performance of specific techniques and attention to detail in complex situations can make a big difference in open sternum patients treated with temporary, vacuum-assisted dressings. Achieving vacuum and fluid seal is important for sterility, integrity of adjacent skin, and caregiver safety.

3D printing from MRI Data: Harnessing strengths and minimizing weaknesses.

3D printing facilitates the creation of accurate physical models of patient-specific anatomy from medical imaging datasets. While the majority of models to date are created from computed tomography (CT) data, there is increasing interest in creating models from other datasets, such as ultrasound and magnetic resonance imaging (MRI). MRI, in particular, holds great potential for 3D printing, given its excellent tissue characterization and lack of ionizing radiation. There are, however, challenges to 3D printing from MRI data as well. Here we review the basics of 3D printing, explore the current strengths and weaknesses of printing from MRI data as they pertain to model accuracy, and discuss considerations in the design of MRI sequences for 3D printing. Finally, we explore the future of 3D printing and MRI, including creative applications and new materials. LEVEL OF EVIDENCE: 5 J. Magn. Reson. Imaging 2017;45:635-645.

Successful Repair of Acute Type A Aortic Dissection 15 Years Following Bilateral Lung Transplantation.

This report describes a patient treated for acute type A aortic dissection 15 years after undergoing bilateral lung transplantation by a clamshell thoracotomy.

Late Surgical Bleeding Following Total Artificial Heart Implantation.

INTRODUCTION: Mechanical circulatory support for heart failure, including the Total Artificial Heart (TAH, Syncardia, Tucson, AZ, USA) has increased in recent years. This report describes bleeding complications associated with the device. METHODS: A single institution prospectively maintained quality improvement database was reviewed encompassing the first year of clinical experience with the TAH. Patients who underwent TAH implantation were identified, and a review of complications and outcomes was undertaken. RESULTS: Ten patients underwent TAH implant. Four patients experienced delayed postoperative bleeding. In three patients the manifestation of bleeding was tamponade and evidenced by TAH decreased cardiac output. In two patients, at postoperative days 31 and 137, there was a partial disruption of the aortic anastomosis along the outer curvature with pseudoaneurysm formation. Both were repaired by primary suture closure, without use of cardiopulmonary bypass. There was no mortality attributable to bleeding. CONCLUSIONS: TAH patients are at risk for delayed postoperative bleeding, often manifest as an acute decrease in cardiac output. Due to pulsatility and high dP/dT, bleeding from the aortic anastomosis should be considered in the differential of a patient with low flow and/or tamponade.

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.

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.

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.