Publications by authors named "Louis M Chu"

Background: The recommendation for transcatheter aortic valve replacement (TAVR) or surgical aortic valve replacement (SAVR) in patients 65 to 80 years of age is equivocal, leaving patients with a difficult decision. We evaluated whether TAVR compared to SAVR is associated with reduced odds for loss of independent living in patients ≤65, 66 to 79, and ≥80 years of age. Further, we explored mechanisms of the association of TAVR and adverse discharge.

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Intracardiac metastasis of cervical squamous cell carcinoma (C-SCC) is rare, with historically poor long-term survival. We report the case of a 55-year-old woman with prior metastatic C-SCC who was found to have a right ventricular mass causing functional pulmonic stenosis and multiple pulmonary emboli 19 months after her initial diagnosis. She underwent surgical resection to prevent further embolization and heart failure.

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The relationship between carbon monoxide and the heart has been extensively studied in both clinical and preclinical settings. The Food and Drug Administration (FDA) is keenly focused on the ill effects of carbon monoxide on the heart when presented with proposals for clinical trials to evaluate efficacy of this gasotransmitter in a various disease settings. This review provides an overview of the rationale that examines the actions of the FDA when considering clinical testing of CO, and contrast that with the continued accumulation of data that clearly show not only that CO can be used safely, but is potently cardioprotective in clinically relevant small and large animal models.

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Background: Appreciation of unique presentation, patterns and underlying pathophysiology of coronary artery disease in women has driven gender based risk stratification and risk reduction efforts over the last decade. Data regarding whether these advances have resulted in unequivocal improvements in outcomes of CABG in women is conflicting. The objective of our study was to assess gender differences in post-operative outcomes following CABG.

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Background: Despite evidence suggesting detrimental effects of perioperative hyperoxia, hyperoxygenation remains commonplace in cardiac surgery. Hyperoxygenation may increase oxidative damage and neuronal injury leading to potential differences in postoperative neurocognition. Therefore, this study tested the primary hypothesis that intraoperative normoxia, as compared to hyperoxia, reduces postoperative cognitive dysfunction in older patients having cardiac surgery.

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Background: Autophagy is an integral component of cellular homeostasis and metabolism. The exact mechanism of impaired autophagy in diabetes mellitus is unknown. Forkhead Box O3 (FOXO3α) is a key regulator of oxidative stress-related responses.

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Importance: Hospital outcomes for transcatheter aortic valve replacement (TAVR) may be dependent on the quality of evaluation, personnel, and procedural and postprocedural care common to patients undergoing cardiac surgery.

Objectives: We sought to assess whether those hospitals with better patient outcomes for surgical aortic valve replacement (SAVR) subsequently achieved better TAVR outcomes after launching TAVR programs.

Design, Setting, And Participants: This national cohort included US patients 65 years and older.

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We sought to characterize the clinical outcomes and to identify predictors of mortality undergoing isolated tricuspid valve surgery in the United States. We identified 5,164 patients undergoing isolated tricuspid valve surgery from the Centers for Medicare and Medicaid Services Medicare Provider Analysis and Review data between January 2003 and December 2014. The primary outcome was all cause 1-year mortality.

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Pulmonary embolism (PE) can result in rapid clinical decompensation in many patients. With increasing patient complexity and advanced treatment options for PE, multidisciplinary, rapid response teams can optimize risk stratification and expedite management strategies. The Massive And Submassive Clot On-call Team (MASCOT) was created at our institution, which comprised specialists from cardiology, pulmonology, hematology, interventional radiology, and cardiac surgery.

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Background: Moderate alcohol consumption is cardioprotective but the mechanism of action remains unclear. Nuclear factor κ-B regulates the expression of genes involved in inflammation, stress, and apoptosis. We used a swine model of diet-induced metabolic syndrome to investigate the effects of red wine and vodka on nuclear factor κ-B signaling and cytokine activity in chronically ischemic myocardium.

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Background: We previously demonstrated that atorvastatin upregulates proangiogenic proteins and increases arteriolar density in ischemic myocardium. Despite this, there was a lack of collateral-dependent perfusion, possibly related to apoptosis. We utilized a swine model of metabolic syndrome and chronic myocardial ischemia to investigate the effects of atorvastatin on apoptosis.

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Objective: Despite advances in surgical techniques, neurocognitive decline after cardiopulmonary bypass remains a common and serious complication. We have previously demonstrated that patients with neurocognitive decline have unique genetic responses 6 hours after cardiopulmonary bypass when compared with normal patients. We used genomic microarray to objectively investigate whether patients with neurocognitive decline had associated preoperative gene expression profiles and how these profiles changed up to 4 days after surgery.

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Objectives: The perioperative administration of pleomorphic statin drugs has been implicated in improving outcomes after cardiac surgery. Adaptive autophagy is a highly conserved cellular process that allows for the elimination of dysfunctional cell components in response to stress and survival under starving conditions. We sought to investigate the effects of the statin drug atorvastatin on autophagy in ischemic and nonischemic myocardia using a clinically relevant porcine model of metabolic syndrome.

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Objective: Impaired angiogenesis is a known consequence of metabolic syndrome (MetS); however, the mechanism is not fully understood. Recent studies have shown that the notch signaling pathway is an integral component of cardiac angiogenesis. We tested, in a clinically relevant swine model, the effects of MetS on notch and apoptosis signaling in chronically ischemic myocardium.

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Background: Epidemiologic data has shown that metformin confers a survival advantage in patients with cardiovascular disease. Although the underlying cardioprotective mechanism is unclear, it appears to be independent of metformin's insulin-sensitizing effect. The purpose of this study was to evaluate the effect of metformin on the apoptosis pathway in the ischemic and nonischemic cardiac tissue in a swine model of metabolic syndrome.

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Background:  Notch signaling is a highly conserved pathway that promotes vascular and myocardial growth. The hypothesis that exogenous vascular endothelial growth factor (VEGF) administration to ischemic myocardium would enhance the neovascular response and upregulate Notch signaling was assessed.

Methods And Results:  Fourteen male Yorkshire swine underwent placement of an ameroid constrictor on the left circumflex artery to induce chronic myocardial ischemia with half of the animals receiving perivascular VEGF to the ischemic area.

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Background: We investigated the effects of cardioplegic arrest and reperfusion (CP/Rep) on myocardial apoptosis and key apoptotic mediators, such as apoptosis-inducing factor, caspase 3, caspase 8, caspase 9, poly(adenosine diphosphate-ribose) polymerase, B-cell lymphoma 2 (Bcl-2) family proteins, and protein kinase C (PKC), in uncontrolled type 2 diabetic, controlled type 2 diabetic, and nondiabetic patients.

Methods And Results: Right atrial tissue was harvested pre- and post-CP/Rep from uncontrolled type 2 diabetic patients (hemoglobin A1c=9.6 ± 0.

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Resveratrol is a naturally occurring polyphenol found in the skin of red grapes, peanuts, and red wine that has been shown to modify many cardiovascular risk factors. Small animal models have been extensively used to investigate cardiovascular disease, but the results often fail to translate in clinical trials. Disease-specific pig models are emerging as clinically useful tools that may offer insight into cardiovascular disease and the effect of drugs such as resveratrol on cardiovascular health.

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Objective: The purpose of this study is to evaluate the effect of metformin on insulin signaling in ischemic cardiac tissue in a swine model of metabolic syndrome.

Methods: Ossabaw miniswine were fed either a regular diet (Ossabaw control [OC]) or a hypercaloric diet (Ossabaw high cholesterol [OHC], Ossabaw high cholesterol with metformin [OHCM]). After 9 weeks, all animals underwent placement of an ameroid constrictor to the left circumflex artery to induce chronic ischemia.

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Objective: The purpose of the present study was to evaluate the effect of atorvastatin on oxidative stress and angiogenesis in ischemic myocardium in a clinically relevant porcine model of the metabolic syndrome.

Methods: Sixteen Ossabaw pigs were fed either a high-fat diet alone or a high-fat diet supplemented with atorvastatin (1.5 mg/kg daily) for 14 weeks.

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Background: We investigated the effects of cardiopulmonary bypass (CPB) on peripheral arteriolar reactivity and associated signaling pathways in poorly controlled (UDM), controlled (CDM), and case-matched nondiabetic (ND) patients undergoing coronary artery bypass grafting (CABG).

Methods And Results: Skeletal muscle arterioles were harvested before and after CPB from the UDM patients (hemoglobin A1c [HbA1c]=9.0 ± 0.

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Background: Moderate consumption of alcohol, particularly red wine, has been shown to decrease cardiac risk. We used a hypercholesterolemic swine model of chronic ischemia to examine the effects of 2 alcoholic beverages on the heart.

Methods And Results: Yorkshire swine fed a high-cholesterol diet underwent left circumflex ameroid constrictor placement to induce chronic ischemia at 8 weeks of age.

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Objective: Previous experiments in Yorkshire swine demonstrated significantly fewer pericardial adhesions and intramyocardial collagen deposition at reoperative sternotomy in animals supplemented with vodka but not with red wine. The purpose of this experiment was to determine a mechanism for adhesion reduction.

Methods: Twenty-seven male Yorkshire swine were fed a high-cholesterol diet to simulate conditions of coronary artery disease followed by the surgical placement of an ameroid constrictor to the left circumflex coronary artery to induce chronic ischaemia.

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Background: The purpose of this study was to examine the effects of alcohol in the context of metabolic syndrome on insulin signaling pathways in the liver and skeletal muscle.

Methods: Twenty-six Yorkshire swine were fed a hypercaloric, high-fat diet for 4 weeks then split into 3 groups: hypercholesterolemic diet alone (HCC, n = 9), hypercholesterolemic diet with vodka (HCVOD, n = 9), and hypercholesterolemic diet with wine (HCW, n = 8) for 7 weeks. Animals underwent intravenous dextrose challenge before euthanasia and tissue collection.

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Background: Resveratrol has been shown to reverse some of the detrimental effects of metabolic syndrome (MetS). We sought to define the impact of supplemental resveratrol on normal myocardium remote from an ischemic territory in a swine model of MetS and chronic myocardial ischemia.

Study Design: Yorkshire swine were fed a normal diet (control), a high cholesterol diet (HCD), or a high cholesterol diet with orally supplemented resveratrol (HCD-R; 100 mg/kg/day).

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