What is the weakest point of a secured aortic cannula in central extracorporeal membrane oxygenation?

PURPOSE: The purpose of this study was to compare techniques for securing the aortic extracorporeal membrane oxygenation (ECMO) cannula, using in vitro models. METHODS: Two models were studied: a tissue model using porcine aortas and a stand model replacing the aorta with a metal stand to study the system independent of the tissue. Interventions in each model were divided into three experimental groups: Group 1 (3-0 Prolene® + 20-French Medtronic Arterial Cannula EOPA™), Group 2 (4-0 Prolene® + 16-French Medtronic Arterial Cannula DLP Pediatric), and Group 3 (5-0 Prolene® + 8-French Medtronic Arterial Cannula DLP Pediatric). In separate experiments, both gradual and rapid forces were applied to the cannulas, starting with 9.8 Newtons and increasing exponentially if the cannula remained secured. Additionally, the method of securing the tourniquet and the number of ties securing the tourniquet to the cannula were evaluated. RESULTS: In the tissue model, even with a minimum force of 9.8 Newtons, the suture pulled through the aortic tissue, leaving sutures and ties intact. In the stand model, two purse-string sutures secured by two ligaclips held the cannula reliably and withstood higher total force. Dislodgement was prevented at forces close to 60 Newtons with only two hemostatic clips included in cannulation. CONCLUSIONS: The weakest part of the aortic ECMO cannulation system using in vitro experiments was the tissue. Assuming that these experiments translate in vivo, it is therefore critical to prevent any pull on the cannulas by securing ECMO cannulas and ECMO tubing to both the patient and the patient's bed. Sutures with a larger diameter withstand more force. Two medium hemostatic clips can secure Prolene® sutures within snares as safely as a mosquito hemostat. Two polypropylene purse-string sutures secured by two hemostatic clips were most reliable at greater forces. The rationale for publishing our experiments in this manuscript is to (1) communicate our quantification of possible contributing factors to this rare and likely catastrophic complication of unintended decannulation, (2) increase awareness about this potential complication, and (3) increase vigilance to assure prevention of this dreaded complication.

Comprehensive Approach to the Management of Patients with HLHS: Analysis of 100 Consecutive Neonates.

BACKGROUND: We report our comprehensive approach to patients with hypoplastic left heart syndrome (HLHS) and describe our outcomes in 100 consecutive neonates. METHODS: One-hundred consecutive neonates (2015-2023) were stratified into 3 pathways: Pathway(1): 77/100=77% were standard-risk and underwent initial Norwood (Stage 1). Pathway(2): 10/100=10% were high-risk with noncardiac risk factors and underwent initial Hybrid Stage 1. Pathway(3): 13/100=13% were high-risk with cardiac risk factors: 10 underwent initial Hybrid Stage 1 + ventricular assist device insertion (HYBRID+VAD), while 3 underwent primary transplantation. RESULTS: One-year mortality=9/100=9%. Pathway(1): Operative Mortality for initial Norwood (Stage 1)=2/77=2.6%. Of 75 survivors of Norwood (Stage 1): 72 underwent successful Glenn, 2 underwent successful biventricular repair, and 1 underwent successful cardiac transplantation. Pathway(2): Operative Mortality for initial Hybrid Stage 1 without VAD=1/10=10%. Of 9 survivors of Hybrid (Stage 1): 4 underwent successful cardiac transplantation, 2 died while awaiting cardiac transplantation, 3 underwent Comprehensive Stage 2 (with 1 death), and 1 underwent successful biventricular repair. Pathway(3): Of 10 HYBRID+VAD: 7/10=70% underwent successful cardiac transplantation and are alive today and 3/10=30% died on VAD while awaiting transplantation. Median VAD support time=134 days (range=56-226). (Two of three patients who were bridged-to-transplant with prostaglandin underwent successful transplantation and one died while awaiting transplantation.) CONCLUSIONS: A comprehensive approach to the management of patients with HLHS is associated with Operative Mortality after Norwood of 2/77=2.6% and an overall one-year mortality of 9/100=9%. 10/100 patients=10% were stabilized with HYBRID+VAD while awaiting transplantation. VAD facilitates survival on the waiting list during prolonged wait times.

Ruptured Sinus of Valsalva Aneurysm: Three Case Reports and Literature Review.

Sinus of Valsalva aneurysm rupture (SOVAR) into the right cardiac chambers is an uncommon complication with unusual presentation, high morbidity and mortality, and unique hemodynamics as well as cardiac imaging findings. Here, we present three SOVAR cases (two with rupture into the right atrium and one with rupture into the right ventricle) that were initially confused for ventricular septal defects and describe their initial presentation, cardiac imaging studies, invasive hemodynamics, as well as treatment options. Some of the unique findings of SOVAR patients include an acute presentation, often with hemodynamic decompensation, the presence of a continuous murmur on examination, and also hemodynamics that include wide pulse pressure and right heart volume overload.

Pediatric Heart Transplantation Over 36 Years and Contemporary Volume-Outcome Analysis of UNOS.

BACKGROUND: This study examines 36 years of national pediatric heart transplantation data to 1) identify trends in transplant volume, centers, and one-year graft survival, and 2) assess how center transplant volume impacts outcomes over a contemporary 11-year period. METHODS: We performed a retrospective review of pediatric patients (<18 years) undergoing heart transplantation from 1/1/1987 to 12/31/2022 using the United Network for Organ Sharing Database. Trend analyses included the whole cohort, while volume-outcome analyses included a contemporary cohort to account for the temporal changes observed in transplant survival. Highest volume centers were defined by the number of heart transplants performed per center per year. RESULTS: Over 36 years, 11,828 pediatric heart transplants were performed. Transplant volume steadily rose, the number of centers remained stable, and one-year graft survival has improved significantly. In the contemporary era (2012-2022), 89 centers conducted 4,959 pediatric heart transplants. The top 15% high-volume centers (13 centers) accounted for 48.3% (2,393) of transplants, with an average of 16.7±3.8 transplants per center annually, compared to 3.9±3.1 for lower volume centers. Despite transplanting higher risk patients, high-volume centers had similar postoperative outcomes and improved long-term survival. CONCLUSIONS: While the number of US pediatric heart transplant centers has remained stable, pediatric heart transplant volume is steadily increasing, as is one-year graft survival. In a contemporary cohort, the top 15th percentile highest volume centers accounted for 48.3% of US pediatric heart transplants and transplanted higher risk patients with similar postoperative outcomes and improved longitudinal survival.

Combined en bloc heart and liver organ procurement.

A combined heart+liver transplant is the only option for survival in some patients with end-stage combined cardiac and hepatic disease. These patients may suffer from congenital or acquired cardiac disease. The potential aetiologies of the associated hepatic disease are heterogeneous and include systemic disease that impacts the liver as well as venous congestion in patients with functionally univentricular circulation. In the latter scenario, patients with functionally univentricular circulation often require complex cardiac reconstruction in the setting of a cardiac transplant after staged palliation. During cardiac procurement, our approach is to dissect the entire ascending aorta and aortic arch in continuity; the entire superior caval vein and innominate vein in continuity; and the pulmonary arteries from hilum to hilum if the donor is not a candidate for recovery of the lungs. The cardiac and abdominal organ procurement teams work in parallel during dissection and combined en bloc cardio-hepatectomy. This technique minimizes exposure of both organs to cold ischaemia. This video tutorial demonstrates the key steps for combined en bloc heart+liver organ procurement.

Prevalence and Risk Factors for Cerebral Palsy in Children With Congenital Heart Disease Based on Risk of Surgical Mortality.

BACKGROUND: Children with congenital heart disease (CHD) have a higher prevalence of motor impairment secondary to brain injury, resulting in cerebral palsy (CP). The purpose of this study is to determine the prevalence of CP in CHD in a single-center cohort, stratify risk based on surgical mortality using Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery (STAT) categories and identify risk factors. METHODS: Retrospective cohort study of pediatric patients registered in the University of Florida (UF) Society of Thoracic Surgeons Congenital Heart Surgery database from 2006 to 2017 with a diagnosis of CHD who continued follow-up for more than two years at UF. RESULTS: A total of 701 children with CHD met inclusion criteria. Children identified to have CP were 54 (7.7%). Most common presentation was spastic hemiplegic CP with a Gross Motor Function Classification System of level 2. Analysis of surgical and intensive care factors between the two groups showed that children with CHD and CP had longer time from admission to surgery (P = 0.003), higher STAT categories 4 and 5 (P = 0.038), and higher frequency of brain injury and seizures (P < 0.001). Developmental disabilities and rehabilitation needs were significantly greater for children with CHD and CP when compared with those with CHD alone (P < 0.001). CONCLUSIONS: In our cohort, 7.7% children with CHD develop CP; this is significantly higher than the 2010 US population estimate of 0.3%. Our study suggests higher STAT categories, brain injury, and seizures are associated with developing CP in children with CHD.

The safe addition of nitric oxide to the sweep gas of the extracorporeal membrane oxygenation circuit in a pediatric cardiac intensive care unit.

Background: Nitric Oxide (NO) is a naturally occurring modulator of inflammation found in the human body. Several studies in the pediatric cardiothoracic surgery literature have demonstrated some beneficial clinical effects when NO is added to the sweep gas of the cardiopulmonary bypass circuit.Purpose: Our primary aim was to determine the safety of incorporating nitric oxide into the oxygenator sweep gas of the extracorporeal membrane oxygenation (ECMO) circuit. Secondarily, we looked at important clinical outcomes, such as survival, blood product utilization, and common complications related to ECMO.Methods: We performed a single center, retrospective review of all patients at our institution who received ECMO between January 1, 2017 and March 31, 2023. We began additing NO to the ECMO sweep gas in 2019. Results: There were no instances of clinically significant methemoglobinemia with the addition of NO to the sweep gas (0% vs 0%, p = 1). The median daily methemoglobin level was higher in those who received NO via the sweep gas when compared to those who did not (1.6 vs 1.1, p = <0.001). Conclusions: The addition of NO to the sweep gas of the ECMO circuit is safe.

15-Year Analysis of Surgical Approaches and Outcomes for Coarctation in 132 Neonates and Infants.

A variety of surgical approaches exist to treat aortic coarctation in neonates and infants. Our institutional approach is designed to match the surgical approach to the individual anatomy of the patient. The objective of this study is to evaluate operative characteristics and outcomes of all neonates and infants who underwent surgical repair of coarctation of the aorta or hypoplastic aortic arch at University of Florida from 2006 to 2021, inclusive, either in isolation or with concomitant repair of atrial septal defect (ASD) and/or ventricular septal defect (VSD). A retrospective review was performed of 132 patients aged 0-1 year who underwent surgical repair of aortic coarctation or hypoplastic aortic arch between 2006 and 2021, inclusive, either in isolation or with concomitant repair of ASD and/or VSD. Patients were divided into two groups based on the surgical approach: Group 1 = Median Sternotomy and Group 2 = Left Lateral Thoracotomy. Continuous variables are presented as median (minimum-maximum); categorical variables are presented as N (%). The most common operative technique in Group 1 was end-to-side reconstruction with ligation of the aortic isthmus. The most common operative technique in Group 2 was extended end-to-end repair. Operative Mortality was one patient (1/132 = 0.76%). Transcatheter intervention for recurrent coarctation was performed in seven patients (7/132 = 5.3%). Surgical re-intervention for recurrent coarctation was performed in three patients (3/132 = 2.3%). From these data, one can conclude that a strategy of matching the surgical approach to the anatomy of neonates and infants who underwent surgical repair of aortic coarctation or hypoplastic aortic arch, either in isolation or with concomitant repair of ASD and/or VSD, is associated with less than 1% Operative Mortality and less than 3% recurrent coarctation requiring reoperation.

Venovenous extracorporeal membrane oxygenation neck cannulation in an infant.

In this video tutorial, we present neck cannulation for venovenous extracorporeal membrane oxygenation using a crescent right atrial double lumen cannula in a 4-kg baby.

A single-institutional experience with 36 children less than 5 kilograms supported with the Berlin Heart: Comparison of congenital versus acquired heart disease.

OBJECTIVES: We reviewed outcomes in all 36 consecutive children <5 kg supported with the Berlin Heart pulsatile ventricular assist device at the University of Florida, comparing those with acquired heart disease (n = 8) to those with congenital heart disease (CHD) (n = 28). METHODS: The primary outcome was mortality. The Kaplan-Meier method and log-rank tests were used to assess group differences in long-term survival after ventricular assist device insertion. T-tests using estimated survival proportions were used to compare groups at specific time points. RESULTS: Of 82 patients supported with the Berlin Heart at our institution, 49 (49/82 = 59.76%) weighed <10 kg and 36 (36/82 = 43.90%) weighed <5 kg. Of 36 patients <5 kg, 26 (26/36 = 72.22%) were successfully bridged to transplantation. (The duration of support with ventricular assist device for these 36 patients <5 kg was [days]: median = 109, range = 4-305.) Eight out of 36 patients <5 kg had acquired heart disease, and all eight [8/8 = 100%] were successfully bridged to transplantation. (The duration of support with ventricular assist device for these 8 patients <5 kg with acquired heart disease was [days]: median = 50, range = 9-130.) Twenty-eight of 36 patients <5 kg had congenital heart disease. Eighteen of these 28 [64.3%] were successfully bridged to transplantation. (The duration of support with ventricular assist device for these 28 patients <5 kg with congenital heart disease was [days]: median = 136, range = 4-305.) For all 36 patients who weighed <5 kg: 1-year survival estimate after ventricular assist device insertion = 62.7% (95% confidence interval = 48.5-81.2%) and 5-year survival estimate after ventricular assist device insertion = 58.5% (95% confidence interval = 43.8-78.3%). One-year survival after ventricular assist device insertion = 87.5% (95% confidence interval = 67.3-99.9%) in acquired heart disease and 55.6% (95% confidence interval = 39.5-78.2%) in CHD, P = 0.036. Five-year survival after ventricular assist device insertion = 87.5% (95% confidence interval = 67.3-99.9%) in acquired heart disease and 48.6% (95% confidence interval = 31.6-74.8%) in CHD, P = 0.014. CONCLUSION: Pulsatile ventricular assist device facilitates bridge to transplantation in neonates and infants weighing <5 kg; however, survival after ventricular assist device insertion in these small patients is less in those with CHD in comparison to those with acquired heart disease.

Comparison of different porcine models simulating myocardial cold ischemia of pediatric donor hearts.

BACKGROUND: Our team previously identified a stem cell-derived cardioprotective additive that can be added to standard cardioplegia to extend myocardial viability during prolonged myocardial cold ischemic time (CIT) in rodent models. The purpose of this study was to utilize a porcine model to compare in-vivo versus ex-vivo porcine simulation of CIT that accompanies cardiac transplantation in humans, in order to determine an optimal method for translation of our studies to larger animals. METHODS: Eight 39-55 kg Yorkshire X pigs were randomly assigned to either in-vivo or ex-vivo simulation. After administration of general anesthesia and endotracheal intubation, baseline measurement of left ventricular performance was obtained via transesophageal echocardiography (TEE). After midline sternotomy and heparin administration, the aorta was cross-clamped and two liters of HTK-Custodiol were introduced via the aortic root. The in-vivo method utilized cold ischemic heart storage in the chest cavity while supporting the experimental animal with cardiopulmonary bypass (CPB). The ex-vivo method involved standard cardiac procurement, cold ischemic storage outside of the body, and subsequent cardiac reperfusion utilizing cardiac reanimation in a Langendorff heart perfusion mode. After CIT, measurements of post-ischemic left ventricular performance were obtained via echocardiography. Results are presented as: Mean ± Standard Deviation (Median, Minimum-Maximum). RESULTS: Weight (kilograms) was similar in the in-vivo group and the ex-vivo group: 44 ± 1.8 (44, 42-46) versus 44 ± 5.1 (43.5, 39-51), respectively. Cold ischemic time (minutes) was longer in the ex-vivo group: 360 ± 0 (360, 360-360) versus 141 ± 26.7 (149, 102-163). Temperature (degrees Celsius) was colder in the ex-vivo group: 8 ± 0 (8, 8-8) versus 16.5 ± 4.2 (16, 12-16).In the in-vivo group, baseline ejection fraction and ejection fraction after CIT were: 48.25% ± 14.95% (48.5%, 33%-63%) and 41.25% ± 22.32% (41.5%, 20%-62%), respectively. In the ex-vivo group, baseline ejection fraction and ejection fraction after CIT were: 56.4% ± 5.9% (57%, 50%-67%) and 60.4% ± 7.7% (61.5%, 51.9%-67%), respectively. CONCLUSION: The ex-vivo technique is suitable to evaluate cardioplegia additives that may substantially extend myocardial tolerance to cold ischemia.

Epstein Barr virus-directed T-cell therapy for refractory EBV-PTLD in a toddler post Orthotopic heart transplantation.

Epstein-Barr Virus (EBV) is a ubiquitous herpes type virus that is associated with post-transplant lymphoproliferative disorder (PTLD). Usual management includes reduction or cessation of immunosuppression and in some cases chemotherapy including rituximab. However, limited therapies are available if PTLD is refractory to rituximab. Several clinical trials have investigated the use of EBV-directed T cells in rituximab-refractory patients; however, data regarding response is scarce and inconclusive. Herein, we describe a patient with EBV-PTLD refractory to rituximab after orthotopic heart transplantation (OHT) requiring EBV-directed T-cell therapy. This article aims to highlight the unique and aggressive clinical presentation and progression of PTLD with utilization of EBV-directed T-cell therapy for management and associated pitfalls.

The biological role and future therapeutic uses of nitric oxide in extracorporeal membrane oxygenation, a narrative review.

BACKGROUND: Nitric oxide (NO) is a gas naturally produced by the human body that plays an important physiological role. Specifically, it binds guanylyl cyclase to induce smooth muscle relaxation. NO's other protective functions have been well documented, particularly its protective endothelial functions, effects on decreasing pulmonary vascular resistance, antiplatelet, and anticoagulation properties. The use of nitric oxide donors as vasodilators has been known since 1876. Inhaled nitric oxide has been used as a pulmonary vasodilator and to improve ventilation perfusion matching since the 1990s. It is currently approved by the United States Food and Drug Administration for neonates with hypoxic respiratory failure, however, it is used off-label for acute respiratory distress syndrome, acute bronchiolitis, and COVID-19. PURPOSE: In this article we review the currently understood biological action and therapeutic uses of NO through nitric oxide donors such as inhaled nitric oxide. We will then explore recent studies describing use of NO in cardiopulmonary bypass and extracorporeal membrane oxygenation and speculate on NO's future uses.

Reconsidering FDA Guidelines: A Single-Center Experience of Prolonged Impella 5.5 Support.

OBJECTIVE: Impella 5.5 (Abiomed, Danvers, MA, USA) is approved by the US Food and Drug Administration (FDA) for mechanical circulatory support for ≤14 days. It is unknown whether prolonged support is associated with worse outcomes. We sought to review our single-center experience with Impella 5.5 and compare outcomes based on support duration. METHODS: We retrospectively reviewed adult patients (≥18 years old) supported with Impella 5.5 at our institution (May 2020 to April 2023). Patients on prolonged support (>14 days) were compared with those supported for ≤14 days. RESULTS: There were 31 patients supported with Impella 5.5 including 14 (45.2%) supported >14 days. Median support duration for those on prolonged support was 43.5 (interquartile range [IQR] 25 to 63.5) days versus 8 (IQR 6, 13) days for those who were not (P < 0.001). Overall, the device-related complication rate was 9.7% and did not differ between groups (P = 0.08). Overall, 30-day postimplant survival was 71% and did not differ by support duration (P = 0.2). In-hospital mortality was 32% and did not differ between cohorts (P > 0.99). Among those surviving to explant (n = 22), long-term strategy included bridge to durable ventricular assist device (18%, n = 4), cardiac transplant (55%, n = 12), and cardiac recovery (27%, n = 6). CONCLUSIONS: High-risk patients with cardiogenic shock may be supported with Impella 5.5 beyond the FDA-approved duration without increased risk of complications or mortality.

Using interleukin-18, Eotaxin-1, and Eotaxin-3 to identify brain injury in neonates with congenital heart disease.

OBJECTIVES: Serum biomarkers for brain injury in neonates with congenital heart disease (CHD) provide a bedside tool for early identification and intervention. In this preliminary study, we aim to evaluate IL-18, Eotaxin-1 and Eotaxin-3 as biomarkers for the detection of brain injury in neonates with CHD. METHODS: We prospectively enrolled seven neonates diagnosed in-utero with CHD and obtained serum samples at birth, before and after surgery. Samples were analyzed using a human cytokine/chemokine multiplex assay. Brain injury was diagnosed on brain MRI before surgery. RESULTS: Samples from seven neonates at four time points before surgery and three time points after surgery were analyzed. A significant difference was found in neonates with brain injury compared to CHD neonates without. Elevations in interleukin (IL)-18 pre- and post-operative (p = 0.007), IL-18 pre-operative (p = 0.046), Eotaxin-1 pre-operative (p = 0.011), and Eotaxin-3 pre- and post-operative (p = 0.026) were found in CHD neonates with brain injury. CONCLUSION: This is the first published report on the use IL-18, Eotaxin-1, and Eotaxin-3 in the detection of brain injury for neonates with CHD. These biomarkers may provide an actionable target for neuroprotection through immunomodulation. Larger cohorts are needed to determine the significance and clinical utility of these biomarkers.

Defining the Spectrum of Hypoplastic Left Heart Syndrome (HLHS).

The 2021 International Paediatric and Congenital Cardiac Code and the Eleventh Revision of the International Classification of Diseases provide the following definition for hypoplastic left heart syndrome (HLHS): "Hypoplastic left heart syndrome (HLHS) is defined as a spectrum of congenital cardiovascular malformations with normally aligned great arteries without a common atrioventricular junction, characterized by underdevelopment of the left heart with significant hypoplasia of the left ventricle including atresia, stenosis, or hypoplasia of the aortic or mitral valve, or both valves, and hypoplasia of the ascending aorta and aortic arch." Although HLHS with intact ventricular septum (HLHS + IVS) and HLHS with ventricular septal defect (HLHS + VSD) are different cardiac phenotypes, both of these lesions are part of the spectrum of HLHS.

Outcomes of Children Supported With Pulsatile Paracorporeal Ventricular Assist Device: Congenital Versus Acquired Heart Disease.

BACKGROUND: We reviewed the outcomes of 82 consecutive pediatric patients (less than 18 years of age) supported with the Berlin Heart ventricular assist device (VAD), comparing those with congenital heart disease (CHD; n = 44) with those with acquired heart disease (AHD; n = 37). METHODS: The primary outcome was mortality after VAD insertion. Kaplan-Meier methods and log-rank tests were used to assess group differences in long-term survival. RESULTS: Forty-four CHD patients were supported (age: median = 65 days, range = 4 days-13.3 years; weight [kg]: median = 4, range = 2.4-42.3). Ten biventricular CHD patients were supported with eight biventricular assist devices (BiVADs), one left ventricular assist device (LVAD) only, and one LVAD converted to BiVAD, while 34 univentricular CHD patients were supported with single ventricle-ventricular assist devices (sVADs). In CHD patients, duration of VAD support was [days]: median = 134, range = 4-554. Of 44 CHD patients, 28 underwent heart transplantation, 15 died on VAD, and one was still on VAD. Thirty-seven AHD patients were supported (age: median = 1.9 years, range = 27 days-17.7 years; weight [kg]: median = 11, range = 3.1-112), including 34 BiVAD and 3 LVAD. In AHD patients, duration of VAD support was [days]: median = 97, range = 4-315. Of 37 AHD patients, 28 underwent transplantation, three died on VAD, five weaned off VAD (one of whom underwent heart transplantation 334 days after weaning), and one was still on VAD. One-year survival after VAD insertion was 59.9% (95% CI = 46.7%-76.7%) in CHD and 88.6% (95% CI = 78.8%-99.8%) in AHD, P = .0004. Five-year survival after VAD insertion was 55.4% (95% CI = 40.8%-75.2%) in CHD and 85.3% (95% CI = 74.0%-98.2%) in AHD, P = .002. CONCLUSIONS: Pulsatile VAD facilitates bridge-to-transplantation in neonates, infants, and children with CHD; however, survival after VAD insertion is worse in patients with CHD than in patients with AHD.