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    Sex Differences in the Oxidative Stress and Inflammation Response During and After Simulated Hemorrhage in Humans
    (2020) Rosenberg, Alexander; Luu, My-Loan; Anderson, Garen; Rickards, Caroline; Barnes, Haley J.
    Introduction: Hemorrhage (i.e., massive blood loss) induces an oxidative stress and inflammatory response that can persist even following hemostasis and resuscitation. In this study, we hypothesized that young males would elicit a greater oxidative stress and inflammatory response compared to young females, both during and after simulated hemorrhage. Methods: Healthy human subjects (10F; 10M) participated in a presyncopal lower body negative pressure (LBNP) protocol (simulating hemorrhage). Stroke volume was estimated as a marker of central hypovolemia (indexed to body surface area). Venous blood samples were collected at baseline, at the onset of presyncope, and 60-min into recovery ("resuscitation"). Oxidative stress and inflammation responses were assessed via measurement of circulating F2-Isoprostanes (F2-IsoP) and interleukin (IL)-6 and IL-10. Results: LBNP tolerance time was similar between male and female subjects (Males, 1592±124 s vs. Females, 1437±113 s; P=0.37), and stroke volume index decreased by a similar magnitude at presyncope (Males, -50.2±6.3% vs. Females, -49.4±3.2%; P=0.87). There was no effect of time or sex on the %Δ [F2-IsoP] during or after LBNP (P≥0.12). However, male subjects exhibited a greater increase in both the %Δ [IL-6] and %Δ [IL-10] compared to female subjects at the 60-min recovery time point (IL-6: Males, 101.4±138.9% vs. Females, 12.3±34.0%; P=0.06. IL-10: Males, 71.1±133.3% vs. Females, -2.2±11.8%; P=0.06). Conclusion: These data suggest there may be a sex difference in the inflammatory response to blood loss and subsequent fluid resuscitation.
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    Effect of Sodium Glucose Co-Transporter 2 Inhibitors on Blood Pressure Time in Therapeutic Range
    (2020) Yuet, Cheng; Zhou, Zhengyang; Gibson, Caitlin; Petersen, Sydney
    Purpose: Sodium-glucose co-transporter 2 (SGLT2) inhibitors are antihyperglycemic medications that lower blood glucose levels by altering renal glucose reabsorption. SGLT2 inhibitors reduce blood pressure (BP) levels through increased diuresis and decreased sympathetic tone.[1] Due to these mechanisms, SGLT2 inhibitors are associated with improved cardiovascular and renal outcomes.[2] The objective of this study is to determine the association between SGLT2 inhibitors and BP time in therapeutic range (TTR). Consistent BP control in TTR has been shown to impact all-cause mortality.[3] While known to reduce BP levels, whether SGLT2 inhibitors impact the consistency of BP control has not been studied. Methods: This study is a retrospective chart review of adults with type 2 diabetes treated with SGLT2 inhibitors at UNT Health between January 2015 and September 2019. Patients were identified from an electronic report and excluded if the patient used the medication for < 1 month. Each patient serves as their own matched control, by comparing BP readings before and after SGLT2 inhibitor initiation. The target enrollment of 100 patients will achieve 80% power to detect a minimum of 2.46 mmHg reduction in systolic blood pressure (SBP).[4] A one-tailed p-value of < 0.05 will be considered statistically significant. The primary endpoint is TTR defined as the proportion of time that SBP is between 120 and 140 mmHg during the treatment period.[5] Primary endpoints and baseline characteristics will be compared, using paired t-tests for categorical data and chi square tests for nominal data. Results/Conclusion: In progress
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    White Mountain Expedition 2019: Peaks and Valleys - Oscillatory cerebral blood flow at high altitude
    (2020) Rickards, Caroline; Barnes, Haley; Rosenberg, Alexander; Bird, Jordan; Pentz, Brandon; Byman, Britta; Jendzjowsky, Nicholas; Wilson, Richard; Day, Trevor; Anderson, Garen K.
    An oscillatory pattern in cerebral blood flow (at ~0.1 Hz) protects cerebral tissue oxygen saturation (ScO2) under conditions of cerebral hypoperfusion. In this study, we hypothesized that inducing oscillations in cerebral blood flow at 0.1 Hz would protect cerebral blood flow and ScO2 during exposure to combined simulated hemorrhage and sustained hypobaric hypoxia. Eight healthy human subjects (4 M, 24.7 ± 4.1 y; 4 F, 34.3 ± 8.3 y) participated in two lower body negative pressure (LBNP) experiments (simulating hemorrhage) at high altitude (3800 m): 1) 0 Hz control condition (CTRL) and 2) 0.1 Hz oscillatory LBNP (OLBNP) condition. Measurements included internal carotid artery (ICA) blood flow via duplex Doppler ultrasound, middle cerebral artery velocity (MCAv) via transcranial Doppler ultrasound, and ScO2 via near-infrared spectroscopy. Mean MCAv waveforms were fast Fourier transformed to verify oscillations were generated at ~0.1 Hz. Low frequency power (0.07-0.15 Hz) in mean MCAv increased during OLBNP vs. CTRL (P = 0.02). OLBNP did not protect ICA flow (OLBNP: -32.5±4.5 Δ%; CTRL: -19.9±8.9 Δ%; P = 0.18) or mean MCAv (OLBNP: -18.5±3.4 Δ%; CTRL: -15.3±5.4 Δ%; P = 0.58), but ScO2 was protected (OLBNP: -0.67±1.0 Δ%; CTRL: -4.07±2.0 Δ%; P = 0.004). These results support our hypothesis that inducing oscillatory blood flow leads to protection of cerebral tissue oxygenation, despite no differences in ICA blood flow or mean MCAv. Overall, these data suggest that therapies using oscillatory perfusion may help preserve cerebral tissue oxygen saturation under conditions of reduced oxygen delivery.
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    Meta-analysis of modifiable risk factors contributing to incidence of permanent pacemaker implantation following Transcatheter Aortic Valve Replacement
    (2020) Salman, Justin; Azimi, Ariella
    Meta-analysis of modifiable risk factors contributing to incidence of permanent pacemaker implantation following Transcatheter Aortic Valve Replacement By: Ariella Azimi, Justin Salman, and Dr. Scott Ewing Purpose: To conduct a meta-analysis of existing literature investigating risk factors contributing to permanent pacemaker implantation following Transcatheter Aortic Valve Replacement (TAVR), including type of TAVR device, depth of implantation, and membranous septal length. Methods: Perform systematic search of studies using PubMed and Google Scholar that investigate post-TAVR pacemaker placement and provide data on predictors of interest. Summary relative risk and 95% CI for each predictor variable calculated using random effects model. Results: We predict that the type of TAVR device used, depth of implantation, and membranous septal length correlate with the incidence of pacemaker placement in congruence with trends outlined in existing literature but with greater statistical power. Conclusion: Using the result of this meta-analysis, we hope to provide insight into modifiable preprocedural and intraprocedural risk factors that may contribute to future studies affecting the guidelines of TAVR procedures.
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    Aortic Coarctation Repair Outcomes Based on Surgical Approach and Age
    (2020) Burch, Phil; Hamby, Tyler; Ogunyankin, Fadeke; Kway, Kristi
    Background: Coarctation of the aorta, or narrowing of the aorta, accounts for 6-8% of all congenital heart defects. The two most common surgical techniques for repair of coarctation are coarctectomy with end-to-end anastomosis, performed via a lateral thoracotomy approach, and patch aortoplasty, performed via median sternotomy. The purpose of this study is to identify surgical variables that affect long-term outcomes of repair. Methods: This is a retrospective cohort study of patients under one year of age who underwent coarctation repair at Cook Children's Medical Center between January 1, 2014 and March 1, 2018. Exclusion criteria included patients who had complex coexisting cardiac malformations other than atrial septal defect (ASD) or ventricular septal defect (VSD). Using Fisher's Exact test, relationships were examined between type of surgery (lateral thoracotomy vs. medial sternotomy), age at surgery (0-30 vs. 31-365 days), and transverse aortic arch measurement (?-3 vs. >-3 z-score) with elevated blood pressure and incidence of recurrent coarctation. Results: There were 64 patients that met study criteria. We found that type of surgery, age at surgery, and transverse aortic arch measurement had no significant association (p > 0.05) with either blood pressure or recurrence of coarctation. Conclusion: The current data does not support an association between the studied variables and either systemic hypertension and recurrent coarctation. However, the sample size is limited which limits the statistical power of our current study. Increasing the length of time reviewed may identify clinically important relationships.
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    Pyruvate-Enriched Anti-inflammatory Preservation of Explanted, Machine-Perfused Porcine Kidneys
    (2020) Olivencia-Yurvati, Albert; Morales, Jessica; Hodge, Lisa; Mallet, Robert T.; Konty, Logan; Williams, Arthur; Ryou, Myoung-Gwi; Omar,Salma
    Purpose: The gold-standard treatment for end-stage renal disease (ESRD) is kidney transplantation. Although the incidence of ESRD continues to mount, the supply of transplantable kidneys is woefully inadequate. Kidneys obtained from cardiac death victims are a potential source, but oxidative stress and inflammation predispose the organs to acute failure or delayed graft function after transplant. The intermediary metabolite pyruvate possesses energy-yielding, antioxidant and anti-inflammatory properties, and has been found to induce anti-inflammatory erythropoietin production in brain and heart. We postulate pyruvate-enriched preservation of machine-perfused kidneys will preserve organ integrity by increasing renal erythropoietin formation and dampening pro-inflammatory cytokine production. Methods: Kidneys are obtained from juvenile, Yorkshire pigs mechanically ventilated with 2and3% isoflurane. To model donation after cardiac death, the kidneys are harvested after induction of cardiac arrest and 60 minutes of ischemia in situ. After cold saline flush, the right kidney is explanted and perfused via the renal artery with standard organ preservation solution +/- 20 mM pyruvate in a LifePort® organ preservation system at 2-5°C for 72 h. Perfusate is sampled periodically for measurements of pro-inflammatory cytokines TNF-alpha and IL-6 and anti-inflammatory cytokines erythropoietin and IL-1beta. Results: The results are pending, as we are currently acquiring data. Conclusions: The conclusions are pending, but we expect hypothermic machine perfusion with pyruvate-enriched versus standard perfusate will suppress renal release of pro-inflammatory cytokines and increase anti-inflammatory cytokine formation, thereby blunting renal inflammation before transplant.
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    Point of Care Ultrasound Abdominal Aortic Aneurysm Screening: A Quality Improvement Project
    (2020) Hughes, Jonathan; Wright, Joseph; Archer, Jennifer; Miller, Dallas; Aten, Kristopher; Burnett, Isaac; Etherington, Matthew; Pinedo, Samantha; Gibson, John
    The USPSTF recommends a 1-time screening for abdominal aortic aneurysm (AAA) with ultrasonography (US) in men above 65 who have ever smoked. AAA screening has substantially reduced rupture rates. It has been suggested, however, that rates of screening may be well lower in rural areas. The ROME department initiated a quality improvement measure to increase rates of AAA screenings by means of medical students equipped with hand-held US devices. Consenting men above 65 who have ever smoked received an outpatient, point of care ultrasound (POCUS) AAA screening via Butterfly iQ. Screenings of the proximal, middle, and distal portions of the abdominal aorta in both longitudinal and transverse views were conducted. Patients were then referred to the appropriate radiological services to receive a one-time ultrasound screening for AAA. The outcomes compared the variability between the students' and radiologists' measurements and radiology referral compliance. 17 patients were screened in the clinic using the handheld ultrasound device. 2 patients screened positive for AAA at the radiology department, while 1 screened positive in the clinic. The average difference between the measurements by the students and the radiologists was -0.2 cm (95% CI, -0.44 to 0.04; P=0.1). Results yielded no significant difference between measurements obtained by the medical students and the radiology department. The patient follow up compliance rate was only 59%. Based on these data, medical student-performed POCUS AAA screening may provide better compliance and similar accuracy compared to traditional AAA screening.
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    Takotsubo cardiomyopathy caused by COPD exacerbation
    (2020) Aftabizadeh, Som
    Takotsubo cardiomyopathy is characterized by transient left ventricular dysfunction that may be associated with emotional or physical triggers. We present the case of a 57-year-old female with severe COPD who presented with syncope and was found to have stress-induced cardiomyopathy. TCM associated with COPD is a rare and raises the possibility of a common underlying mechanism. A 57-year-old female presented to the ER with respiratory failure after she was found unresponsive. Her past medical history included severe COPD, hypertension, and active tobacco abuse. Her EKG on arrival showed sinus tachycardia and PR segment depression as well as repolarization abnormalities in inferior leads. Labs were significant for elevated BNP and troponemia. An TTE on admission revealed severely reduced LV systolic function and severe diffuse LV hypokinesis. A toxicology screen was notably negative for cocaine. She was treated for COPD exacerbation and NSTEMI and improved over the course of the next three days. Coronary angiography revealed non-obstructive coronary artery disease. Repeat TTE four days after admission showed her LV dysfunction had resolved. TCM is characterized by reversible LV dysfunction that is unrelated to obstructive CAD. While rare, literature of review shows several cases of TCM have been associated with both COPD and asthma exacerbation. With catecholamines playing a key role to the pathogenesis of the disease, beta-adrenergic stimulation may be a potential trigger. Some sources speculate that the disproportionate predominance of sympathetic over parasympathetic activity during a COPD exacerbation could be a trigger for TCM.
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    Acute Pericarditis Caused by Pulmonary Embolism: A Dressler-Like Syndrome
    (2020) Gabbert, Brittany; Aftabizadeh, Som
    Pericarditis presenting as a sequelae of myocardial infarction, pericardiotomy or chest trauma is well recognized; but it is rarely described in association with pulmonary embolism. A 40 year old caucasian male with no significant past medical history presented with new-onset shortness of breath and substernal chest pain worsening over the preceding three days. He is a never smoker. One week prior he drove to Texas from Colorado. The main differential diagnosis based off the history was pulmonary embolism, acute coronary syndrome, pleurisy and musculoskeletal chest pain. Electrocardiogram showed sinus tachycardia with S1Q3T3. Chest CTA showed a saddle embolus and evidence of right ventricular strain. Transthoracic echocardiogram showed markedly dilated right ventricle with mild hypokinesis of the mid free wall and McConnell's sign. EKOS catheter was then placed for 12 hours. The patient improved and was discharged on an oral anticoagulant with scheduled outpatient follow-up. One week later he presented to our ER with chest pain radiating to the back. A friction rub was present on cardiac auscultation. EKG showed normal sinus rhythm with diffuse ST elevation, PR depression and Spodick's sign. Troponin levels were negative, TTE showed improved RV strain and preserved LV function. CRP and ESR were significantly elevated. He was diagnosed with pericarditis and started on indomethacin and colchicine. Pulmonary embolism can cause right heart strain via increased pulmonary vascular pressures. This strain can lead to transmural infarction in the right heart which can then lead to acute pericarditis.
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    The Effects of Obstructive Sleep Apnea on Cardiac Arrhythmia Risk
    (2020) Smith, Michael; Burk, John; Burgess, Lauren; Allen, Julie; Jouett, Noah; Biben, Emily
    Background: Over 20 million people in the United States suffer from Obstructive Sleep Apnea (OSA). Compared to the general population, OSA patients are 2.6 times more likely to experience sudden cardiac death (SCD), and it is suspected that this is due in part to QT prolongation leading to fatal dysrhythmias. We examined the factors that affect QT interval during periods of sleep apnea including OSA severity, time of night, and quantity of obstructive apneic events during sleep. Methods: We determined QTc intervals from the electrocardiograms of 41 patients undergoing polysomnography for diagnosis of OSA. Patients that were selected had an apnea hypopnea index >20/Hr and had no prior heart disease. Each patient's ECG during their sleep study was analyzed to assess QT interval throughout the night. Results: Early analyses of data showed that QTc intervals in early and late apneas were significantly prolonged compared to baseline. Patients with longer apneas tended to have greater increases in QTc. Furthermore, there were no significant differences in the prolongation of QTc between males and females. Conclusions: Sleep apneic events are associated with periods of mild QTc prolongation despite some cardiac cycle shortening. The prolongation tends to become enhanced later in the night, implying that there is a cumulative effect of numerous prior apneas. Future studies will focus on QTc changes in OSA patients with prior heart disease, as these are the patients at greatest risk for serious arrhythmias during the night.
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    Exosome-like vesicles facilitate intercellular communication between uterine artery smooth muscle cells and perivascular adipose tissue
    (2020) Cushen, Spencer; Raetz, Megan; Saranya Conjeevaram Nagarajan, Bhavani; Raut, Sangram; Goulopoulou, Styliani; Osikoya, Oluwatobiloba
    Introduction Perivascular adipose tissue (PVAT) regulates uterine artery tone during pregnancy. However, the mechanisms underlying its functional role in uterine arteries is unknown. Exosomes are cargo carrying membrane-bound extracellular vesicles used in intercellular communication. It is unknown whether PVAT secretes exosomes. We hypothesized that uterine PVAT sheds exosomes (Exo-PVAT) that are uptaken by neighboring uterine vascular smooth muscle cells (USMCs). Methods Exo-PVAT were isolated and purified with tissue culture and ultracentrifugation, and primary USMCs were isolated using enzymatic digestion from pregnant and non-pregnant rats. Exosome protein content, size and molecular weight were determined via western blot, Malvern Zetasizer and fast protein liquid chromatography (FPLC), respectively. To determine USMC uptake of Exo-PVAT, Exo-PVAT were labelled with a membrane-labeling dye and co-cultured with USMCs for 3 hours. Results Exo-PVAT expressed TSG101, Alix, and CD9. Pregnancy did not affect Exo-PVAT size [Median(IQR) (nm), Non-pregnant: 99.4 (80.5) vs. Pregnant: 46.7 (21.2), p=0.5]. Using FPLC, we identified exosomes of 40-200 kDa in samples from both pregnant and non-pregnant rats. PVAT from pregnant rats secreted a relatively high amount of exosomes of 2000 kDa compared to non-pregnat rats. Immunocytochemical assessments revealed that USMCs took up exosomes derived from their adjacent PVAT. Conclusion Uterine PVAT sheds exosome-like vesicles which are uptaken by adjacent USMCs. The interaction between Exo-PVAT and USMCs is a novel type of intercellular communication that may have important implications in uterine artery function and blood flow in pregnancy.
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    The role of acute heating in modulating the pressor response to hypoxic stress
    (2020) Romero, Steven; Smith, Michael; Stedke, Alexandra; Moore, Amy; Hemmingway, Holden; Tran, Apollo
    Repetitive airway obstruction accompanying Obstructive Sleep Apnea (OSA) produces hypoxic stress, which increases sympathetic nerve activity (SNA) and mean arterial pressure (MAP). Acute hot water immersion offers protective benefits by increasing blood flow while decreasing arterial pressure; while this effect has been repeatedly demonstrated, the effect of thermal stress on the vascular response to hypoxic apnea has not been examined. This project investigates whether acute heating alters the cardiovascular responses to acute hypoxic stress. Subjects wear a heated suit to increase their core body temperature; breath-holds are then performed at three different increments, as the subject's temperature increases (~0.4°C, ~0.8°C and ~1.2°C above baseline). After 60 min of heating, a recovery period begins, and subjects repeat the hypoxic breath-holds as temperature decreases by ~0.4°C, ~0.8°C and ~1.2°C. Measurements of arm blood flow, brachial artery blood pressure, HR, ABP, and SpO2 are monitored throughout the experiment. The data is currently being evaluated: outcome variables will be analyzed using a hypoxia condition-time mixed model, and planned comparisons will be used to examine specific group-time interactions based on hypoxia level and time pre and post heating. Our findings may represent a form of physiologic cross-tolerance that could be a model for potential therapeutic intervention in conditions such as OSA. This will enhance the basic understanding of the physiology of these two stress conditions and provide preliminary insights into the possible use of heat conditioning as therapy for conditions related to vascular dysregulation.
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    Case Report: Atypical pheochromocytoma presenting with junctional rhythm tachycardia and troponin elevation
    (2020) Blackwood, Taylor; Chapel, Ashley; Kulp, Dennis
    Background: Pheochromocytomas are rare neuroendocrine neoplasms with an annual incidence of at least 0.8 per 100,000 person-years and peak incidence between the 4th and 5th decade of life. These intraadrenal neoplasms hypersecrete catecholamines leading to aberrations in cardiovascular homeostasis, elevated sympathetic activity, and paroxysms of symptoms such as episodic headache, diaphoresis, tachycardia, and hypertension. Only one third of patients with pheochromocytoma present with classic symptoms, though a growing body of evidence has begun characterizing the atypical features of this disease. Here, we present one such case depicting the unusual presentation of a pheochromocytoma and atypical manifestations of this disease. Case Presentation: A 34-year-old Hispanic-American male presented to the emergency room with sole complaint of epigastric pain. Upon evaluation, ECG revealed the presence of junctional rhythm without ST changes, mildly elevated troponins, and high blood pressures, which was hypersensitive to nicardipine. This initial presentation was mired with discordant information which did not suggest a clear etiology. Upon further investigation, the patient reported a history of episodic shortness of breath, headache, and anxiety attacks which elucidated the clinical image and supported a presumptive suspicion of hypertension and early cardiomyopathy secondary to pheochromocytoma. After successful stabilization and discharge of the patient, 24-hour urine metanephrine results returned confirming elevated catecholamine breakdown products and the diagnosis of pheochromocytoma. The patient was informed of the gravity of his diagnosis and referred for outpatient surgical consult. Conclusion: This case demonstrates an atypical presentation of pheochromocytoma with cardiomyopathic features in a younger patient.
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    Tai Chi and Cardiovascular Conditions
    (2020) Logsdon, Liana; Traina, Allison; Liu, Howe; Salem, Yasser; Kolenovic, Mersida
    Introduction: Tai Chi is a meditative and low intensity exercise that includes deep diaphragmatic breathing which promotes positive physiologic changes in the cardiovascular system. The purpose of this systematic review is to analyze evidence related to the benefits of Tai Chi pertaining to cardiovascular conditions and recognize the similarities of this intervention in research. Methods: This study includes twelve randomized control trial articles that encompass a variety of cardiovascular conditions. The electronic database utilized includes PubMed. Keywords used include Tai Chi intervention, hypertension, chronic heart failure, coronary artery disease, coronary heart disease, atherosclerosis, and myocardial infarction. Results: These articles discuss hypertension, myocardial infarction, atherosclerosis, coronary heart disease, coronary artery disease, heart failure, and cerebrovascular accidents related to a Tai Chi intervention. Significant improvements were observed in the following outcomes measured: TUG, VO2peak, 6MWT, endurance tests, blood pressure, arterial stiffness, blood lipid levels, BMI, blood sugar, cognition, Cardiac Health Behavior scale, quality of life scales, and psychosocial self-reports. The most common intervention protocol used in these articles was a 1-hour session of 24-form Yang style Tai Chi for three times a week over a 12-week period. On the other hand, two articles used a similar protocol but implemented these exercises twice a week over a 12 week period and were still able to see significant improvements in cardiovascular function. Conclusion: Overall, this systematic review reveals the significance of Tai Chi as an exercise that will improve cardiovascular function in a population with cardiovascular disease.
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    Ascending Aortic Thrombus in a patient presenting with Mesenteric Ischemia
    (2020) Cameron, Benjamin; Robbins, Daniel; Peddi, Prashanth; Chastain, Oscar; Soney, Hywel
    Introduction: Ascending aortic thrombus (AAT) is a rare presentation with potential for catastrophic complications including cerebral, visceral, and peripheral emboli. Patients with this condition usually present after an embolic event, often with long-term sequelae. Case: A 54-year-old male with past medical history of prior ischemic strokes, congestive heart failure with reduced ejection fraction (EF 22%), coronary artery disease, hypertension, hyperlipidemia, and tobacco use disorder, presented to the ED with lower abdominal pain that was abrupt, 10/10, crampy, with nausea and vomiting. Abdominal exam revealed mild hypogastric tenderness out of proportion to stated discomfort. Initial labs revealed WBC count of 21,300 cells/mm3, troponin peaking at 5.73 ng/ml, and lactate of 2.8 mmol/L rising to 7 mmol/L within 6 hours. CT angiogram revealed thrombosis in the superior mesenteric artery (SMA) and a prominent thrombus in the ascending aorta, likely embolic source. Transthoracic echocardiogram revealed an EF of 5-10%. Patient was taken for emergency exploratory laparotomy where SMA thrombectomy and patch angioplasty was successfully performed. Hypercoagulability workup was negative. Due to extensive comorbidities, patient was determined to be a poor candidate for a thrombectomy of the ascending aorta, and anticoagulation was initiated. Discussion: The case is a rare presentation of an AAT with mesenteric ischemia. Chronic heart failure is the suspected etiology, but we were not able to find an association between heart failure and AAT to date. AAT is ideally managed with surgical intervention. Systemic thrombolysis and anticoagulation remain an option, with only few cases reporting successful outcomes.
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    Effect of G-Buttons on Growth Velocity Following Stage I Palliation in Patients with Hypoplastic Left Heart Syndrome
    (2020) Charara, Fatima
    Infants with hypoplastic left heart syndrome (HLHS) who undergo the Norwood procedure are at risk for several major morbidities, including growth failure. Supplemental feeds using a nasogastric tube or gastronomy button (G-button) are often used to improve growth outcomes in HLHS patients between Norwood and Glenn. This study examines whether G-button implantation in the interstage period has a positive effect on growth velocity in patients with HLHS at a single institution. We conducted a retrospective review of patients who underwent the Norwood and Glenn procedures for HLHS from 2007 to 2017 at Cook Children's Medical Center (CCMC) in Fort Worth, Texas. Patients were excluded if they were hospitalized from Norwood to Glenn procedures, or had a G-button implanted post-Norwood discharge. Growth was assessed using World Health Organization (WHO) growth charts to calculate z-scores for body mass index (BMI), height, and weight. Mean z-scores of patients with and without G-buttons were compared from Norwood to Glenn discharge using two-tailed independent samples t-tests. Analysis of the z-scores for BMI, height, and weight revealed significantly greater weight gain in patients with G-buttons (mean=0.54, SD=0.67) from Norwood to Glenn discharge than in those without G-buttons (mean=0.07, SD=0.75; p=0.009). Additionally, compared to those without G-buttons, patients with G-buttons experienced non-significant increases in weight; there was no meaningful difference in height. Further study is required in order to discern what effect this improved weight gain may have on long term outcomes.
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    Preoperative factors affecting mortality in HLHS patients undergoing the Norwood procedure
    (2020) Ogunyankin, Fadeke; Hamby, Tyler; Kuo, James; Karnkowska, Barbara
    Hypoplastic left heart syndrome (HLHS) is characterized by hypoplasia of the left heart and outflow tract. The three-stage surgical reconstruction of heart consists of circumventing the underdeveloped left ventricle by connecting right ventricle to systemic circulation and grafting a passive flow conduit which shunts venous blood into pulmonary artery. First stage surgery (Norwood) has the highest mortality among common congenital surgeries (7-19%) followed by a high risk interstage (IS) phase where additional 4-15% of infants die. A retrospective chart review of HLHS patients was conducted at Cook Children's hospital between January 2007 and January 2017. Objective of the study was to identify preoperative risk factors that may lead to premature death during IS. Univariate logistic regression analyses were used to determine whether feeding, intubation, and extracorporeal membrane oxygenation (ECMO) predicted mortality. IS was defined as time following Norwood procedure until Glenn, the second stage of reconstruction. Analysis revealed that receiving Norwood feeding prior to surgery was associated with lower mortality (OR=0.42, CI=0.20-0.90, p= 0.025). Furthermore, intubation prior to surgery (OR=1.73, CI=1.05-2.85, p= 0.03) and pre-operative ECMO (OR=2.83, CI=1.12-7.19, p=0.028) were associated with higher IS mortality. Current findings suggest a positive relationship between pre-operative respiratory interventions and increased rate of post-operative mortality. This relationship suggests that pulmonary status and inability to feed may be the leading prognostic factors in IS infant death. Norwood nutrition and continued respiratory support warrant further studies in order to understand the clinical implications of these findings.
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    Acute Coronary Syndrome with Chief Complaint of Arm Pain: An Atypical Case Presentation
    (2020) Huber, Trevor; Puia, Justin
    Introduction: Typically, Acute Coronary Syndrome (ACS) present with "pressure like, squeezing" substernal chest pain, with possible radiation to left jaw, arm, neck, and upper back. Additionally, autonomic symptoms, like diaphoresis, nausea and vomiting are also common. In the following ACS case, symptoms include localized left arm pain, mild muscle ache on the left chest, and mild dizziness without the typical symptoms of pressure-like chest pain, nausea, vomiting, or diaphoresis. Presentation: A 49-year-old male with history of 4 pack-years of tobacco smoke use presented to urgent care with left arm pain. He thought the pain to be related to history of left arm fracture as a child. This episode of left arm pain lasted 4 hours and did not improve with acetaminophen. He also reported a "muscle ache" over the left chest, and slight lightheadedness. He denied sub-sternal pressure, shortness of breath, nausea, vomiting, or diaphoresis. Initial EKG at urgent care showed lateral T-wave changes and point of care (POC) troponin test was 0.13 ng/ml. POC Troponin-I at hospital ED was 0.76 ng/ml. Cardiac catheterization revealed occlusion of 3 coronary arteries and 3 drug-eluting stents were subsequently placed. Conclusion: Patients with atypical presentation of ACS that are not initially diagnosed with ACS have greater morbidity and mortality. Keep atypical symptoms of ACS in mind when evaluating patients. High sensitivity POC Troponin I could reduce diagnostic time with potential for major benefits for patients and emergency departments.
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    Plasma Endothelin-1 is Increased in the Recovery from Acute Leg Heating in Older Adults
    (2020) Hemingway, Holden; Engelland, Rachel; Olivencia-Yurvati, Albert; Romero, Steven; Tomasco, Olivia
    Blood pressure is reduced in older adults following exposure to acute leg heating, but mechanisms mediating this hypotensive response are unknown. We tested the hypothesis that plasma endothelin-1, a potent vasoconstrictor, would be attenuated concurrently with blood pressure in older adults following acute leg heating. Thirteen young and ten older adults were exposed to 45 minutes of leg heating. Plasma endothelin-1 concentrations were measured immediately prior to and 30 minutes into recovery from heating. Mean arterial blood pressure was well maintained in young adults (pre-heat, 86±6 mmHg vs. recovery, 88±7 mmHg; P = 0.4), but was markedly reduced in older adults (pre-heat, 101±7 mmHg vs. recovery, 94±6 mmHg; P < 0.05). Systemic vascular conductance did not differ from pre-heat (69±3 ml min-1 mmHg-1) to recovery (70±3 ml min-1 mmHg-1; P = 0.7) in young adults, whereas conductance was increased in older adults (pre-heat, 55±6 ml min-1 mmHg-1 vs. recovery, 62±5 ml min-1 mmHg-1; P = 0.07). Plasma endothelin-1 was increased in both groups following leg heating (young adults, [delta]0.23±0.42 pg ml-1; older adults [delta]0.20±0.43 pg ml-1; P< 0.05). Despite increased plasma endothelin-1, blood pressure was reduced in parallel with an increase in systemic vascular conductance which suggests that endothelin-1-mediated vasoconstriction may be altered following leg heating in older adults. Alternatively, increased endothelin-1 may be preventing a further deleterious reduction in blood pressure by restraining the increase in systemic vascular conductance.