Propranolol Therapy in Tetralogy of Fallot: Treating the Echocardiogram or Treating the Patient.

Hypercyanotic spells are one of the defining clinical features of Tetralogy of Fallot (TOF). Limited data exist on peak Doppler right ventricular outflow tract (RVOT) gradient as a risk factor for the development of hypercyanotic spells, frequency of prophylactic use of propranolol based on peak RVOT gradient, and its impact on preventing the occurrence of hypercyanotic spells. We aimed to quantify peak RVOT gradients as measured on transthoracic echocardiography in infants with unrepaired TOF and assess for correlation with clinical symptoms of hypercyanotic spells. We also assessed the frequency of pre-operative use of propranolol, indication for medication initiation, and occurrence of hypercyanotic spells with or without propranolol use. Retrospective analysis was performed on patients at our institution who were born between February 1, 2011 and May 31, 2023. Patients were excluded if they were maintained on prostaglandin infusion or underwent palliative shunt placement or balloon valvuloplasty prior to complete surgical repair. Demographics, occurrence of hypercyanotic spells, propranolol use, peripheral oxygen saturation, age at surgical repair, and peak RVOT gradient at the time of propranolol initiation were collected from the electronic medical record. If no propranolol use was recorded, the single highest maximum RVOT gradient prior to surgery was collected. 203 patients were identified, of which 92 patients were included in analysis. Thirty-six (39%) patients received propranolol and 19% of patients developed hypercyanotic spells prior to surgery. Patients with higher peak RVOT gradients were more likely to be started on propranolol even in the absence of overt symptoms, and they also demonstrated more systemic desaturation. Additionally, peak RVOT gradient was found to be a poor predictor for the development of hypercyanotic spells. Wide clinical variation exists in the prophylactic use of propranolol for prevention of hypercyanotic spells. Peak RVOT gradient is not a reliable tool for prophylactic propranolol initiation to prevent hypercyanotic spells.

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.

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.

A Comprehensive Approach to the Management of Patients With HLHS and Related Malformations: An Analysis of 83 Patients (2015-2021).

Background: Some patients with hypoplastic left heart syndrome (HLHS) and HLHS-related malformations with ductal-dependent systemic circulation are extremely high-risk for Norwood palliation. We report our comprehensive approach to the management of these patients designed to maximize survival and optimize the utilization of donor hearts. Methods: We reviewed our entire current single center experience with 83 neonates and infants with HLHS and HLHS-related malformations (2015-2021). Standard-risk patients (n = 62) underwent initial Norwood (Stage 1) palliation. High-risk patients with risk factors other than major cardiac risk factors (n = 9) underwent initial Hybrid Stage 1 palliation, consisting of application of bilateral pulmonary bands, stent placement in the patent arterial duct, and atrial septectomy if needed. High-risk patients with major cardiac risk factors (n = 9) were bridged to transplantation with initial combined Hybrid Stage 1 palliation and pulsatile ventricular assist device (VAD) insertion (HYBRID + VAD). Three patients were bridged to transplantation with prostaglandin. Results: Overall survival at 1 year = 90.4% (75/83). Operative Mortality for standard-risk patients undergoing initial Norwood (Stage 1) Operation was 2/62 (3.2%). Of 60 survivors: 57 underwent Glenn, 2 underwent biventricular repair, and 1 underwent cardiac transplantation. Operative Mortality for high-risk patients with risk factors other than major cardiac risk factors undergoing initial Hybrid Stage 1 palliation without VAD was 0/9: 4 underwent transplantation, 1 awaits transplantation, 3 underwent Comprehensive Stage 2 (with 1 death), and 1 underwent biventricular repair. Of 9 HYBRID + VAD patients, 6 (67%) underwent successful cardiac transplantation and are alive today and 3 (33%) died while awaiting transplantation on VAD. Median length of VAD support was 134 days (mean = 134, range = 56-226). Conclusion: A comprehensive approach to the management of patients with HLHS or HLHS-related malformations is associated with Operative Mortality after Norwood of 2/62 = 3.2% and a one-year survival of 75/83 = 90.4%. A subset of 9/83 patients (11%) were stabilized with HYBRID + VAD while awaiting transplantation. VAD facilitates survival on the waiting list during prolonged wait times.

ß1-receptor polymorphisms and junctional ectopic tachycardia in children after cardiac surgery.

Junctional ectopic tachycardia (JET) is a potentially life-threatening postoperative arrhythmia in children with specific congenital heart defects and can contribute significantly to postoperative morbidity for at-risk populations. In adults, ß1-adrenergic receptor (ADRB1) and ß2-adrenergic receptor (ADRB2) genotypes have been associated with increased risk for arrhythmias. However, their association with arrhythmia risk in children is unknown. We aimed to test associations between ADRB1 and ADRB2 genotypes and postoperative JET in patients with congenital heart defects. Children who underwent cardiac surgery were genotyped for the ADRB1 p.Ser49Gly (rs1801252; c.145A>G), p.Arg389Gly (rs1801253; c.1165C>G), ADRB2 p.Arg16Gly (rs1042713; c.46A>G), and p.Glu27Gln (rs1042714; c.79G>C) polymorphisms. The occurrence of postoperative JET was assessed via cardiologist-interpreted electrocardiograms. Genotype associations with JET were analyzed via logistic regression, adjusted for clinical variables associated with JET, with separate analysis in patients not on a ß-blocker. Of the 343 children included (median age 8 months, 53% boys, 69% European ancestry), 45 (13%) developed JET. The Arg389Arg genotype was not significantly associated with JET in the overall population (odds ratio [OR] = 1.96, 95% confidence interval [CI] = 0.96-4.03, p = 0.064), but was nominally associated in patients not taking a ß-blocker (n = 324, OR = 2.25, 95% CI = 1.05-4.80. p = 0.034). None of the other variants were associated with JET. These data suggest that the ADRB1 Arg389Arg genotype may predict risk for JET following cardiac surgery in pediatric patients in the absence of ß-blockade. Whether treatment with a ß-blocker ameliorates this association requires further research.

Risk Factors for Seizures and Epilepsy in Children With Congenital Heart Disease.

OBJECTIVES: To identify potential risk factors for pre- and postoperative seizures and epilepsy in children with congenital heart disease. METHODS: Retrospective cohort study of neonates and infants <3 months of age with congenital heart disease who underwent cardiopulmonary bypass from November 24, 2006, until June 1, 2015. Children with seizures were classified based on time of occurrence into early preoperative, early postoperative, and late postoperative. Children with recurring seizures 30 days after cardiac surgery met criteria for epilepsy. RESULTS: 247 patients completed follow-up; 2.4% had seizures early preoperation and 1.6% early postoperation. Late postoperative epilepsy occurred in 5.3% of the cohort. The majority of seizures in the late postoperative epilepsy group started after 1 year of age (mean 1.53 years, range = 0.18-4.7 years). One of the 13 patients with epilepsy had a seizure during their intensive care unit hospitalization. Potential risk factors for seizures included brain injury (P < .001), high-risk surgery (Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery score ≥3, P = .024), and low birth weight (P < .04). Infants with stroke were more likely to develop epilepsy (P = .04). Presence of seizures was associated with increased length of stay (P < .001). CONCLUSIONS: Our study suggests an association between children with congenital heart disease diagnosed with stroke in the neonatal/infancy period and the development of epilepsy. These children may not have prior early pre- and postoperative seizures. Risk factors for seizures include brain injury, high-risk surgery, and lower birth weight. Seizures were associated with an increased length of stay but did not necessarily lead to subsequent epilepsy.

Safety of a 2-Day Antibiotic Regimen After Delayed Chest Closure Post Pediatric Cardiac Surgery.

BACKGROUND: There is no consensus for the length of prophylactic antibiotics after delayed chest closure (DCC) postcardiac surgery in pediatrics. In September 2014, our institution's pediatric cardiac intensive care unit changed the policy on length of prophylactic antibiotics after DCC from 5 days (control) to 2 days (study group). The objective of the study was to determine whether a 2-day course of antibiotics is as effective as a 5-day course in preventing blood stream and sternal wound infections in pediatric DCC. METHODS: Retrospective and prospective study. Primary end points included incidence of sternal wound infections and positive sternal imaging for infection. Surrogate markers of infection were collected at 4 time points. RESULTS: During the study period, 139 patients had DCC postcardiac surgery of which 110 patients were included for analysis, 54 patients in the control and 56 in the study group. There was no difference in total number of positive wound cultures/chest computed tomography (CT) findings (4/54 [7.5%] control vs 5/56 [8.9%] study group, P = .3), positive blood cultures (P = .586), median postsurgical length of stay (P = .4), or readmissions within 30 days postsurgery (P = .6). All secondary end points were similar in both groups except peak heart rate between weeks 2 and 4 (P = .041). CONCLUSION: Two days of prophylactic antibiotics is not inferior to 5 days of prophylactic antibiotics after DCC following pediatric cardiac surgery.

Impact of 3D Printouts in Optimizing Surgical Results for Complex Congenital Heart Disease.

Planning corrective and palliative surgery for patients who have complex congenital heart disease often relies on the assessment of cardiac anatomy using two-dimensional noninvasive cardiac imaging modalities (echocardiography, cardiac magnetic resonance imaging, and computed tomography scan). Advances in cardiac noninvasive imaging now include the use of three-dimensional (3D) reconstruction tools that produce 3D images and 3D printouts. There is scant evidence available in the literature as to what effect the availability of 3D printouts of complex congenital heart defects has on surgical outcomes. Surgical outcomes of study subjects with a 3D cardiac printout available and their paired control subject without a 3D cardiac printout available were compared. We found a trend toward shorter surgical times in the study group who had the benefit of 3D models, but no statistical significance was found for bypass time, cross-clamp time, total time, length of stay, or respiratory support. These preliminary results support the proposal that 3D modeling be made readily available to congenital cardiac surgery teams, for use in patients with the most complex congenital heart disease.

A single centre experience with an evolving approach for the repair of coarctation of the aorta.

BACKGROUND: Isolated coarctation of the aorta can be repaired by either lateral thoracotomy or sternotomy approach with end-to-end anastomosis. Most commonly, neonates with coarctation of the aorta also have hypoplasia of the arch, requiring median sternotomy and extended end-to-side anastomosis with arch augmentation. The aim of this study was to describe our experience as the institution adopted the median sternotomy approach for repair, by reviewing complications, mortality, and reintervention. METHODS: Retrospective chart review of 66 patients aged 0-1 year who had arch repair performed by a single surgeon over an 8-year period was performed. Median age at surgery was 22 days (4-232) and median weight was 3.08 kg (1.25-8.0). Forty-one (62%) patients underwent median sternotomy. RESULTS: There was 1 death from a noncardiac cause. Eighteen per cent of our patients were ≤2.5 kg. Vocal cord paresis occurred in 16% of patients under 2.5 kg and 9.5% of patients 2.5 kg or above at the time of surgery. Hypertension at 6-month follow-up was greater in patients under 2.5 kg (44%) than patients 2.5 kg or above (15%). Total surgical reintervention rate was 6%. For patients above 2.5 kg, the surgical reintervention rate was 5.4% and for patients below 2.5 kg, the surgical reintervention rate was 8.3%. CONCLUSION: We concluded that for neonates with coarctation of the aorta and hypoplastic arch, median sternotomy is a safe surgical approach with low morbidity and mortality with the possible advantage of reduced surgical re-intervention and mortality in the population below 2.5 kg.

Infectious complications of ventricular assist device use in children in the United States: Data from the Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs).

BACKGROUND: Infections are frequent in pediatric ventricular assist device (VAD) patients. In this study we aimed to describe infections in durable VAD patients reported to Pedimacs. METHODS: Durable VAD data from the Pedimacs registry (September 19, 2012 to December 31, 2015) were analyzed. Infections were described with standard descriptive statistics, Kaplan-Meier analysis and competing outcomes analysis. RESULTS: There were 248 implants in 222 patients, with a mean age and a median follow-up of 11 ± 6.4 years and 2.4 patient-months (<1 day to 2.6 years), respectively. Device types were pulsatile flow (PF) in 91 (41%) patients and continuous flow (CF) in 131 (59%) patients. PF patients were younger (4 ± 4 vs 14 ± 4 years; p < 0.0001) and were more likely to have congenital heart disease (25% vs 12%; p = 0.03), prior surgery (53% vs 26%; p < 0.0001) and prior extracorporeal membrane oxygenation (24% vs 7%; p = 0.0003). Infection accounted for 17% (96 of 564) of the reported adverse events (AEs). A non-device infection was most common (51%), followed by sepsis (24%), external pump component infection (20%) and internal pump component infection (5%). Most infections were bacterial (73%) and required intravenous therapy only (77%). The risk of infection in the constant phase was higher in patients with a history of prior infection and in patients with a history of a non-infectious major AEs. Survival was lower after infection only in CF patients (p = 0.008). CONCLUSIONS: Infection was the most common AE after pediatric VAD implantation. Non-device infections were most common. The best predictor of a future infection was a past infection. CF patients have higher risk of death after an infection.

Severe Direct Hyperbilirubinemia as a Consequence of Right Heart Failure in Congenital Heart Disease.

Adult literature documents increased cholestasis in right heart failure yet is poorly documented in the pediatric population. We describe three infants with congenital heart disease who developed significantly elevated direct bilirubin levels of 43, 23, and 12 mg/dL, respectively, in the absence of hepatic dysfunction. The common hemodynamic pathophysiology in these infants is right heart dysfunction with moderate to severe tricuspid regurgitation in the setting of low perfusion state. Right heart dysfunction in infants can result in severe conjugated bilirubin, likely as a consequence of venous congestion and can be used as an indirect marker of right heart dynamics.

Generation of lung adenocarcinoma DNA aptamers for cancer studies.

Lung cancer is the most lethal malignancy in the world, and each year thousands of people die from this disease. Early detection has proven to increase the 5-year survival for this cancer in general, independent of the origination site in the lung. To address this challenge, we have used cell-based SELEX (Systematic Evolution of Ligands by Exponential Enrichment) to select a panel of aptamers capable of distinguishing lung adenocarcinoma cells from normal lung epithelial cells. These aptamers bind at physiological and formalin-fixed conditions and display affinity for their targets with apparent K(d')s in the nanomolar range. Our findings suggest that the selected aptamers have the potential to be used in clinical settings, as well as to improve classification of nonsurgical specimens, another current challenge in lung cancer.

DNA aptamers as molecular probes for colorectal cancer study.

BACKGROUND: Understanding the molecular features of specific tumors can increase our knowledge about the mechanism(s) underlying disease development and progression. This is particularly significant for colorectal cancer, which is a heterogeneous complex of diseases developed in a sequential manner through a multistep carcinogenic process. As such, it is likely that tumors with similar characteristics might originate in the same manner and have a similar molecular behavior. Therefore, specific mapping of the molecular features can be potentially useful for both tumor classification and the development of appropriate therapeutic regimens. However, this can only be accomplished by developing high-affinity molecular probes with the ability to recognize specific markers associated with different tumors. Aptamers can most easily meet this challenge based on their target diversity, flexible manipulation and ease of development. METHODOLOGY AND RESULTS: Using a method known as cell-based Systematic Evolution of Ligands by Exponential enrichment (cell-SELEX) and colorectal cancer cultured cell lines DLD-1 and HCT 116, we selected a panel of target-specific aptamers. Binding studies by flow cytometry and confocal microscopy showed that these aptamers have high affinity and selectivity. Our data further show that these aptamers neither recognize normal colon cells (cultured and fresh), nor do they recognize most other cancer cell lines tested. CONCLUSION/SIGNIFICANCE: The selected aptamers can identify specific biomarkers associated with colorectal cancers. We believe that these probes could be further developed for early disease detection, as well as prognostic markers, of colorectal cancers.

Study of the molecular recognition of aptamers selected through ovarian cancer cell-SELEX.

BACKGROUND: Ovarian cancer is the most lethal gynecological malignancy, and the ovarian clear cell carcinoma subtype (OCCA) demonstrates a particularly poor response to standard treatment. Improvements in ovarian cancer outcomes, especially for OCCA, could be expected from a clearer understanding of the molecular pathology that might guide strategies for earlier diagnosis and more effective treatment. METHODOLOGY/PRINCIPAL FINDINGS: Cell-SELEX technology was employed to develop new molecular probes for ovarian cancer cell surface markers. A total of thirteen aptamers with K(d)'s to ovarian cancer cells in the pico- to nanomolar range were obtained. Preliminary investigation of the targets of these aptamers and their binding characteristics was also performed. CONCLUSIONS/SIGNIFICANCE: We have selected a series of aptamers that bind to different types of ovarian cancer, but not cervical cancer. Though binding to other cancer cell lines was observed, these aptamers could lead to identification of biomarkers that are related to cancer.

Using aptamers evolved from cell-SELEX to engineer a molecular delivery platform.

We report a chemically modified construct of the Sgc8 aptamer, selected against CEM cells, conjugated to an activator platform for stimulated release of molecules at the tumor surface using DNA template assisted functional group transfer reactions (DTGTR).

Applications of aptamers in cancer cell biology.

Identifying cells associated with specific disease states is critically important for the early detection and diagnosis of cancer. To facilitate this task, molecular probes, which bind biomarkers that are either specifically or differentially expressed in diseased cells relative to healthy cells, provide a simple and effective method. This review focuses on the use of DNA aptamers as molecular probes for cancer cells. These aptamers are created by means of the cell-based Systematic Evolution of Ligands by EXponential enrichment (SELEX) process, which uses whole disease cells as targets. We describe at length the steps of the cell-SELEX process and discuss several applications for the aptamers, including profiling leukemia patient samples and discovering cell-surface cancer biomarkers. We conclude with a discussion of an aptamer-conjugated nanoparticle enrichment and detection scheme.

Sonochemically induced covalent binding of calf thymus DNA by aziridinylquinones.

Sonolysis of argon- or oxygen-containing samples in the presence of calf thymus DNA and the diaziridinylquinones 2,5-bis-aziridin-1-yl-3,6-dichloro-1,4-benzoquinone (AZClQ) and 2,5-bis(carboethoxyamino)-3,6-diaziridinyl-1,4-benzoquinone (AZQ) produced quinone-DNA covalent adducts at pH 5.5 and to a much lesser extent at pH 7.4. The corresponding semiquinone derivatives are detected using EPR spectroscopy after sonolysis of argon-saturated solutions at pH 7.4. The amount of covalent adducts decreases with addition of SOD, indicating a role of superoxide in this process. Addition of oxygen to the purging gas decreased but did not eliminate this covalent adduct. Thus this work suggests a possible synergism between bioreductive quinones and ultrasound in antitumor therapies based on alkylating quinone-DNA adduct formation with potential applications to both hypoxic and normally oxygenated conditions.

Sonochemistry of antitumor quinones in argon-saturated aqueous solutions: enhanced ferricytochrome c reduction.

Sonolysis of argon-saturated aqueous antitumor quinone solutions resulted in an enhancement in ferricytochrome c (Cyt c) reduction. Partial inhibition of these reduction enhancements by addition of superoxide dismutase evidences the production of superoxide ions. No correlation between quinone hydrophobicity or redox potential is observed in the extent of Cyt c reduction. The semiquinone of the parent quinone as well as other quinone-derived reductants are proposed as the electron shuttle intermediates which reduce Cyt c.