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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Evaluation of the Sodium Calcium Exchange Inhibitor

Ali, Ahmad 13 May 2011 (has links)
Arresting the heart with cardioplegia solution is the usual strategy to protect the myocardium during cardiac surgery. However, ischemia-reperfusion injury, due in part to Ca2+ overload, remains a clinical problem. Ca2+ influx during ischemia occurs through reverse mode action of the Na+/Ca2+ exchanger. We therefore tested the hypothesis that delivering the Na+/Ca2+ exchanger blocker SEA0400 to a cardioplegia solution would result in superior myocardial protection during ischemic-cardioplegic arrest. Studies were performed on isolated hearts and individual cardiomyocytes from young adult male Fisher Rats. Hearts arrested with cardioplegia containing SEA0400 showed improved recovery of left ventricular function after reperfusion. The onset of reperfusion arrhythmia was delayed, troponin release was reduced, and mitochondrial damage was minimized. In the isolated cell model, contraction amplitudes were higher during reperfusion in the SEA0400 group without a change in Ca2+ transients. This suggests that cells arrested with cardioplegia containing SEA0400 developed improved myofilament sensitivity to Ca2+.
2

Custodiol Versus Blood Cardioplegia: Comparison of Myocardial Protection in Adult Cardiac Cases

Boros, Daniella January 2013 (has links)
Objectives: When used as a cardioplegic solution, Custodiol® HTK solution is typically administered in a single-dose, allowing the operation to be performed continuously. This is an advantage over alternative cardioplegic solutions that may have to be re-administered every 20-30 minutes. Although Custodiol is widely used as a cardioplegic solution in Europe, its use for myocardial protection remains an off-label indication in the United States. Thus, the aim of this study is to compare the efficacy of Custodiol to standard 4:1 blood cardioplegia in adult cardiac cases. METHODS: This study was a single-center retrospective review of prospectively collected data. Adult cardiac cases performed between November 2011 and August 2013 using Custodiol® were compared to cases using standard Plegisol® 4:1 blood cardioplegia. Twenty-six primary intra-operative and post-operative endpoints were compared including 30-day mortality, 30-day hospital readmission, prolonged mechanical ventilation time, and renal failure. RESULTS: Of the 229 cases identified, 63 cases used Custodiol and 166 used 4:1 blood cardioplegia. Demographics were similar in both groups with a mean patient age of 65.27±15.07 years for Custodiol and 66.72±12.85 years for 4:1 blood cardioplegia. The average cardiopulmonary bypass time for Custodiol and 4:1 blood cardioplegia was 124.76±61.45 and 137.93±54.05 minutes respectively. The Custodiol group had a greater incidence of prolonged ventilation (>24 hours), 20.6% versus 15.1% respectively, and this approached statistical significance with a p value of 0.052. Intra-operative blood usage was significantly higher in the Custodiol group compared to the blood cardioplegia group, with 44.4% of patients receiving fresh frozen plasma during the operation compared to only 25.3% in the blood cardioplegia group (p=0.005). The results revealed no statistically significant difference in 30-day mortality, 30-day hospital readmission, renal failure, and stroke. CONCLUSION: Despite the distinct advantage of long-term ischemic tolerance, Custodiol use was associated with an increased requirement for fresh frozen plasma during the perioperative period when compared to blood cardioplegia.
3

Cardioprotective effect of Na+/Ca2+ exchange inhibition in cardioplegic arrest by SEA0400

Egar, Jeanne 06 August 2013 (has links)
This study investigated the effects of SEA0400, a Na+/Ca2+ exchange inhibitor, in cardioplegia on rat myocyte contractile function. SEA0400 significantly reduced the accumulation of diastolic Ca2+ throughout cardioplegic arrest compared to ischemic control and cardioplegia. Cells treated with SEA0400 during cardioplegic arrest showed significantly larger Ca2+ transient amplitudes and contractions throughout reperfusion compared to cells treated with cardiopelgia alone. Intracellular Ca2+ stores were similar in both cardioplegic groups at baseline and during reperfusion. Together these results suggest that SEA0400 has beneficial effects at protecting ventricular myocytes during cardioplegic arrest and that SEA0400 in cardioplegia may affect myofilament Ca2+ sensitivity.
4

Protecting The Aged Heart During Cardiac Surgery: Use of del Nido Cardioplegia Provides Superior Functional Recovery in Isolated Hearts

Govindapillai, Arun 07 August 2013 (has links)
The purpose of this study was to determine if del Nido cardioplegia provides superior protection for aged and young adult hearts. We used our isolated working heart model of cardioplegic arrest and reperfusion to compare functional recovery in both senescent and young adult rat hearts, with delivery of del Nido or our standard cardioplegia. In the aged hearts, use of del Nido cardioplegia prevented spontaneous contractions during arrest, reduced troponin release, and provided superior functional recovery during working heart. In contrast, in the young adult hearts, although stroke work was higher in the del Nido group, there were no significant differences in spontaneous activity, troponin release, and cardiac output between del Nido and standard cardioplegia, suggesting that del Nido cardioplegia did not provide superior functional recovery in the young adult heart. Del Nido cardioplegia has the potential to provide superior myocardial protection for elderly patients undergoing cardiac surgery.
5

Techniques amenant à réduire le caractère invasif de la chirurgie cardiaque et de l’ischémie / reperfusion myocardique / Techniques aiming to reduce the invasiveness of cardiac surgery and of the myocardial ischemia / reperfusion

Vola, Marco 05 December 2013 (has links)
Dans le cadre du développement d’une stratégie clinique de diminution de l’invasivité de l’acte de Chirurgie cardiaque, axée à la fois sur la réduction du traumatisme de la paroi thoracique, de l’ischémie myocardique peropératoire, et de l’agressivité de la CEC, une étude prospective randomisée a été réalisée pour comparer l’impact sur le métabolisme myocardique en peropératoire de l’utilisation de la cardioplégie cristalloïde Custodiol® versus la solution de cardioplégie de St Thomas au cours de la chirurgie coronarienne. L’objectif de cette étude est de comparer les modifications periopératoire de la concentration dans l’espace interstitiel de lactate, pyruvate, glycérol et glucose dans les deux groupes de cardioplégie et ceci depuis le déclampage jusqu'à 24h en post-opératoire. Matériels et méthodes. Vingt-huit patients ont pu être inclus dans l’étude. Le monitorage a été pratiqué avec la technique de microdialyse (cathéter CMA 70, Analyseur CMA 600, CMA Microdialysis,Sweden), avec une mesure toutes les 10 minutes pendant le temps du clampage et la première heure post déclampage, puis toutes les heures, des concentrations interstitielles des métabolites. Les concentrations plasmatiques des troponines à la sortie du bloc opératoire et à H +12 ont été également évaluées dans les deux groupes. Résultats : Des 28 patients inclus et randomisés, 22 ont pu bénéficier d’un monitorage complet (12 pour le groupe Custodiol® et 10 pour le groupe St Thomas). Six ont été exclus pour des raisons techniques (1 arrachement, 3 plicatures, 1 chute du cathéter et 1 dysfonctionnement de l’analyseur). Une analyse comparative entre les patients inclus et exclus de l’étude ne montre pas de différences significatives pour les facteurs de risque cardiovasculaires, la FEVG, l’âge, le genre. Les valeurs moyennes des concentrations +/- écart type de lactate, pyruvate, glucose et glycérol au déclampage (T0,) sont les suivants : groupe Custodiol® : 2.77+/-1.81 mmol l-1 ; 13.74+/-20.87 μmol l-1 ; 0.46+/-0.84 mmol l-1 ; 196.99+/-122.22 mmol l-1 ; groupe St Thomas : 0.89+/-0.64 mmol l-1 ; 6.49+/-9.10 μmol l-1 ; 0.19+/-0.18 mmol l-1 ; 73.17+/-72.11 mmol l-1. Les temps de CEC et de clampage ont été respectivement dans le groupe Custodiol® de : 94.2+/-14 min et 59.8+/-15 min, et, dans le groupe St Thomas de 82.6+/-15.9 min et 55.8+/-16.29 et min (p=ns). Les concentrations post-opératoires en troponine T (sortie de bloc et H+12) ont été respectivement de 2.8+/-1.8 et 7.4+/-5.3 μmol/L pour le groupe Custodiol® et de 3.3+/-4.0 et 5.0+/-3.6 μmol/L (p=ns) pour le groupe Saint Thomas. Aucun évènement clinique ou électrocardiographique n’a eu lieu en post opératoire dans les deux groupes. Conclusion. Le monitorage de l’état redox myocardique interstitiel a été possible dans les deux groupes de façon sûre et efficace et a permis de déceler des variations des concentrations en métabolites dans les deux groupes en l’absence d’évènements cliniques. Les résultats de ces analyses retrouvent, au déclampage, des concentrations significativement plus hautes de lactate et glycérol dans le groupe Custodiol®. Ces différences s’effacent rapidement pendant la phase de reperfusion avec une tendance (non significative) à une concentration de lactates plus basse dans le groupe de patients du groupe Custodiol®. Des études multicentriques ciblées sur des clampages longs supérieurs à 90 min nous semblent nécessaires pour définir si une différence à la fois métabolique et clinique peut exister entre les différentes solutions de protection cardiaque / In our unit, the challenge is to develop a clinical strategy of reduction of the invasiveness of the “On pump procedure” of cardiac surgery: that means a reduction of the chest wall trauma, of the cross clamping perioperative myocardial ischemia, and of the invasiveness of the extra-corporeal circulation. In this background, we organized a randomized perspective study in order to assess the impact of the perioperative myocardial redox metabolism during the on pump coronary surgery protected with Custodiol® versus St Thomas crystalloid cardioplegias. Objectives: To assess the presence and the severity of the perioperative myocardial ischemia in the Custodiol® versus St Thomas group, defined as the interstitial myocardial concentrations of lactate, pyruvate, glycerol and glucose, at the time of the removal of the aortic clamp. Materials and methods : Twenty height patients could be enrolled in the study and were randomized in the Custodiol® and in the St-Thomas group. Monitoring was assessed with the technique of the cardiac microdialysis (CMA 70 probe, CMA 600 analyzer, CMA Microdialysis, Sweden), by dosing every ten minutes during the aortic cross clamping period and every hour out of the operating room, up to 24 hours, the interstitial myocardial concentrations of Lactate, pyruvate, glycerol and glucose. The Lactate/pyruvate ratio and glucose/lactate ratios and 12 hours post-operative troponin plasmatic concentrations were also assessed. Statistical analysis comparing the Custodiol® versus ST Thomas group were performed via a t-test. Results: Out of the 28 enrolled patients, twenty-two (12 of the Custodiol® group and 10 of the St Thomas group) could be successfully monitored with the microdialysis technique. Six were excluded because of technical reasons (one intempestive ablation, 3 iatrogenic plication of the tube, 1 felled out of the table, one due to a dysfunction of the analyzer). The comparative analysis between included and excluded patients did not prove any statistical result in terms of cardiovascular risk factors, EF, age and gender. At declamping time (T0), mean values of concentrations of lactate, pyruvate, glucose and glycerol were the following: Custodiol® group: 2.77+-1.81 mmol l-1;13.74+-20.87 μmol l-1;0.46+-0. mmol l-1;196.99+-122.22 mmol l-1 ; St Thomas : 0.89+-0.64 mmol l-1 ; 6.49+-9.10 μmol l-1; 0.19+-0.18 mmol l-1; 73.17+-72.11 mmol l-1. Cross clamping and CPB times were respectively 94.2+/-14 et 59.8+/-15 min (Custodiol®), and 82.6+/-15.9 et 55.8+/-16.29 et minutes (St-Thomas) (p=ns) . Post operative plasmatic levels of Troponin (arrival in the ICU and 12 H+12) were respectively de 2.8+/-1.8 and 7.4+/-5.3 (pour le groupe Custodiol®) et de 3.3+/-4.0 et 5.0+/-3.6 μmol/L (Saint Thomas) (ns). Conclusion: Monitoring of the interstitial myocardial redox state was safely possible in both groups and allowed to assess metabolic different findings in the two cardioprotective methods that were not enhanced by perioperative clinical ischemic events. Microdialysis assessed, at the time of aorta declamping, significantly higher concentrations of lactate and Glycerol in the Custodiol® group. That difference regressed during the reperfusion phase with a tendency for a lower lactate level in the Custodiol® group. Multicentric studies focused on cross clamping time longer than 90 minutes seem necessary to enhance metabolic interstitial and clinical superiority between cardioprotective solutions
6

Assessing The Clinical Utility of Non-Depolarizing Cardioplegia & The Challenge Of Evidence-Based Decision Making in an Anecdotal Age of Cardioplegia Comparative Research

Risso, Ashley, Risso, Ashley January 2016 (has links)
PART I Background: For over forty years, depolarizing, hyperkalemic cardioplegia solutions have served as the standard of care for cardiac surgery. While effective in inducing cardiac arrest, potassium-based solutions are associated with an array of negative consequences, such as coagulopathies, conduction dysfunction, inflammation, coronary vasoconstriction, myocardial edema, and ischemic injury. Adenosine-lidocaine-magnesium, a non-depolarizing, non-potassium-containing solution, has recently entered the clinical arena. Animal research suggests that this agent may provide a method of diastolic arrest that is as effective as potassium-based cardioplegia but with improved protective benefits.Purpose: The aim is to assess the safety and efficacy of adenosine-lidocaine-magnesium as a cardioplegia solution in terms of overall patient outcomes.Methodology: In June 2014, Banner University Medical Center Tucson became the first American institution to adopt the use of PolarShot (ALM)--adenosine-lidocaine-magnesium - as a cardioplegia solution. This one-year, retrospective study compares patients receiving adenosine-lidocaine-magnesium to those receiving high-potassium/low-potassium cardioplegia during adult cardiac surgery. Cases compared in this study include isolated coronary artery bypass, isolated aortic/mitral valve repair/replacement, and combination coronary artery bypass/valve replacement surgery only. A propensity-weighted regression model was used for analysis to determine whether or not cardioplegia treatment affected clinical outcome. To assess overall clinical outcome, major morbidity and mortality and post-procedural length of stay were chosen as primary endpoints. Results: In terms of treatment (adenosine-magnesium-lidocaine vs. high-potassium/low-potassium), no statistically significant difference was found between groups in regard to major morbidity and mortality event occurrences nor was a significant difference found between post-procedural length of stay. Discussion: After comparing postoperative outcomes between cardioplegia treatment groups, PolarShot (ALM) cardioplegia produced postoperative outcomes that were statistically similar to those of high-potassium/low-potassium cardioplegia. The confidence in these results is limited by low case volume, surgical case variability, and retrospective nature of this study. Conclusion: According to this propensity-weighted regression model, PolarShot (ALM) cardioplegia appears to be a safe and effective alternative to traditional potassium-based cardioplegia for the purpose of adult cardiac surgery. More research, including prospective randomized trials, is necessary to confirm or deny the findings of this study. PART II Background: Historically, surgical cardioplegia compounding was accomplished by filling patient-tailored prescriptions on-demand. Modern day compounding has become a manufacturing process to improve quality and accommodate physician demand. Additionally, sterile compounding standards have become more stringent, further necessitating a standardized compounding approach. In 2013, scrutiny of sterile drug compounding increased with passage of the Drug Quality and Security Act (DQSA) and subsequent Federal Drug Administration oversight. This federal mandate requires all compounded sterile preparations distributed by 503B Outsourcing Facilities be tested for potency, stability, and sterility. To accomplish this, compounders must significantly reduce batched formula variability. Purpose: A review of 2014 sales data from a large 503B outsourcing facility and cardioplegia compounder will be conducted. The study will identify solution differences and detail its findings. The aim of this study is to assess cardioplegia variability on a national level. Methodology: Results will be summarized by cardioplegia strategy (Buckberg, high-potassium/low-potassium, crystalloid, del Nido, Adenocaine, and microplegia), dilution strategy (4:1 blood-crystalloid, 8:1 blood-crystalloid, 1:4 crystalloid-blood, all-blood, and all-crystalloid), formula constituents (base solutions, additives, buffers), potassium concentrations. Any observed patterns in formula usage will also be reported, geographical or otherwise. Results / Discussion: Based on institutional use, high-potassium/low-potassium (two-solution) multidose strategy was the most common. Based on solutions ordered, the most common cardioplegia ingredient was potassium chloride, present in almost ninety percent (89.64%) of all units sold. After looking at potassium content, extensive variability was noted in terms of potassium added to the bag (undiluted) and potassium to-be delivered (post-dilutional). Additionally, unique solution formulations identified in multiple institutions were often found in neighboring states or within a single state. Conclusion: The results of this analysis illustrate the extent to cardioplegia formula variability nationwide. Variability exists in both methodology and formulation on a state-to-state, institution-to-institution, even across-single-institution basis. This formula customization appears to be institution- and surgeon-specific, suggesting empirical influence in formula adaptation. Formula standardization may be necessary to combat the compounded issue of formula customization moving forward.
7

Epigallocatechin Gallate Reduces Ischemia/Reperfusion Injury in Isolated Perfused Rabbit Hearts

Salameh, Aida, Schuster, Roxana, Dähnert, Ingo, Seeger, Johannes, Dhein, Stefan 30 January 2024 (has links)
Cardioplegic arrest during heart operations is often used in cardiac surgery. During cardioplegia, the heart is subjected to a global ischemia/reperfusion-injury. ()-epigallocatechin gallate (EGCG), one of the main ingredients of green tea, seems to be beneficial in various cardiac diseases. Therefore, the aim of our study was to evaluate EGCG in a rabbit model of cardioplegic arrest. Twenty four mature Chinchilla rabbits were examined. Rabbit hearts were isolated and perfused according to Langendorff. After induction of cardioplegia (without and with 20 mol/L EGCG, n = 6 each) the hearts maintained arrested for 90-min. Thereafter, the hearts were re-perfused for 60 min. During the entire experiment hemodynamic and functional data were assessed. At the end of each experiment, left ventricular samples were processed for ATP measurements and for histological analysis. Directly after cessation of cardioplegia, all hearts showed the same decline in systolic and diastolic function. However, hearts of the EGCG-group showed a significantly faster and better hemodynamic recovery during reperfusion. In addition, tissue ATP-levels were significantly higher in the EGCG-treated hearts. Histological analysis revealed that markers of nitrosative and oxidative stress were significantly lower in the EGCG group. Thus, addition of EGCG significantly protected the cardiac muscle from ischemia/reperfusion injury.

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