Publications by authors named "Theodore Plappert"

Introduction: Functional tricuspid regurgitation (TR) remains a challenging clinical problem with poor outcomes and few effective treatments. Atrial fibrillation (AF) has been associated with functional TR. We sought to determine whether restoring sinus rhythm through catheter ablation of AF can decrease the degree of TR.

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Objective: We sought to determine how sex and dexrazoxane therapy influence cardiac remodelling in children with sarcoma receiving high-dose doxorubicin.

Methods: In a retrospective cohort of 85 children with sarcoma receiving high-dose doxorubicin, echocardiography measures prior to, early after (within 6 months of doxorubicin completion) and 1 - 2 years after doxorubicin completion were quantified. At each follow-up visit, multivariable, propensity-adjusted linear regression models evaluated dexrazoxane's effects on changes in left ventricular (LV) shortening fraction (SF), structure, strain and wall stress for subgroups divided by sex.

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Background: Sunitinib, used widely in metastatic renal cell carcinoma, can result in hypertension, left ventricular dysfunction, and heart failure. However, the relationships between vascular function and cardiac dysfunction with sunitinib are poorly understood.

Methods And Results: In a multicenter prospective study of 84 metastatic renal cell carcinoma patients, echocardiography, arterial tonometry, and BNP (B-type natriuretic peptide) measures were performed at baseline and at 3.

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Background: Cardiovascular disease in patients with breast cancer is of growing concern. The longitudinal effects of commonly used therapies, including doxorubicin and trastuzumab, on cardiac remodeling and function remain unknown in this population. We aimed to define the changes in echocardiographic parameters of structure, function, and ventricular-arterial coupling, and their associations with left ventricular ejection fraction (LVEF) and heart failure symptoms.

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Objectives: Repair for ischemic mitral regurgitation with undersized annuloplasty is characterized by high recurrence rates. We sought to determine the value of pre-repair 3-dimensional echocardiography over 2-dimensional echocardiography in predicting recurrence at 6 months.

Methods: Intraoperative transesophageal 2-dimensional echocardiography and 3-dimensional echocardiography were performed in 50 patients undergoing undersized annuloplasty for ischemic mitral regurgitation.

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Article Synopsis
  • This study aimed to explore how echocardiographic measurements relate to heart damage caused by cancer treatments like doxorubicin and trastuzumab.
  • Doxorubicin and trastuzumab are effective for breast cancer but can lead to significant cardiac issues, highlighting the need for early detection of at-risk patients.
  • The research involved 135 breast cancer patients, tracking echocardiograms over time; results showed certain echocardiographic measures were predictive of cardiac dysfunction, with significant odds ratios suggesting they can identify patients at risk.
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Background: Valve repair for ischemic mitral regurgitation (IMR) with undersized annuloplasty rings is characterized by high IMR recurrence rates. Patient-specific preoperative imaging-based risk stratification for recurrent IMR would optimize results. We sought to determine if prerepair three-dimensional (3D) echocardiography combined with a novel valve-modeling algorithm would be predictive of IMR recurrence 6 months after repair.

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Pulmonary hypertension (PH) is associated with poor outcomes in the dialysis and general populations, but its effect in CKD is unclear. We evaluated the prevalence and predictors of PH measures and their associations with long-term clinical outcomes in patients with nondialysis-dependent CKD. Chronic Renal Insufficiency Cohort (CRIC) Study participants who had Doppler echocardiography performed were considered for inclusion.

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Background: In contrast to the adult, fetal sheep consistently regenerate functional myocardium after myocardial infarction. We hypothesize that this regeneration is due to the recruitment of cardiac progenitor cells to the infarct by stromal-derived factor-1α (SDF-1α) and that its competitive inhibition will block the regenerative fetal response.

Methods: A 20% apical infarct was created in adult and fetal sheep by selective permanent coronary artery ligation.

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Background: Targeted delivery of mesenchymal precursor cells (MPCs) can modify left ventricular (LV) cellular and extracellular remodeling after myocardial infarction (MI). However, whether and to what degree LV remodeling may be affected by MPC injection post-MI, and whether these effects are concentration-dependent, remain unknown.

Methods And Results: Allogeneic MPCs were expanded from sheep bone marrow, and direct intramyocardial injection was performed within the borderzone region 1 hour after MI induction (coronary ligation) in sheep at the following concentrations: 25x10(6) (25 M, n=7), 75x10(6) (75 M, n=7), 225x10(6) (225 M, n=10), 450x10(6) (450 M, n=8), and MPC free media only (MI Only, n=14).

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Background: Glucagon-like peptide-1 (GLP-1) has insulinomimetic, insulinotropic, and antiapoptotic properties that may make it a useful adjunct to reperfusion therapy for myocardial infarction (MI); however, GLP-1 has a short plasma half-life. Fusion of GLP-1 to human transferrin (GLP-1-Tf) significantly prolongs drug half-life.

Materials And Methods: We tested the ability of single dose GLP-1-Tf to limit myocardial ischemia (30 min)/reperfusion (180 min) injury in rabbits.

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Objective: Elective ascending aortic replacement is recommended to prevent acute type A aortic dissection when any segment of the proximal aorta is greater than 5.5 cm. However, little data exist that meticulously describe the size of the ascending aorta at multiple levels in patients who suffer acute type A dissections.

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Background: This experiment assessed the dose-dependent effect of a unique allogeneic STRO-3-positive mesenchymal precursor cell (MPC) on postinfarction left ventricular (LV) remodeling. The MPCs were administered in a manner that would simulate an off-the-self, early postinfarction, preventative approach to cardiac cell therapy in a sheep transmural myocardial infarct (MI) model.

Methods: Allogeneic MPCs were isolated from male crossbred sheep.

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Background: Mild hypothermia (< 4 degrees C) improves myocardial salvage after infarct reperfusion in animals and in early clinical studies. In this experiment the effect of mild hypothermia during ischemia and early reperfusion on long-term postinfarction left ventricular (LV) remodeling was assessed in an ovine infarct model.

Methods: In the initial phase of the experiment the effect of progressive degrees of hypothermia on infarct size was quantified.

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Background: Early infarct expansion after coronary occlusion compromises contractile function in perfused myocardial regions and promotes adverse long-term left ventricular (LV) remodeling. We hypothesized that injection of a tissue-expanding dermal filler material into a myocardial infarction (MI) would attenuate infarct expansion and limit LV remodeling.

Methods: Fifteen sheep were subjected to an anteroapical MI involving approximately 20% of the LV followed by the injection of 1.

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Objectives: Using 3-dimensional echocardiography in conjunction with novel geometric modeling and rendering techniques, we have developed a high-resolution, quantitative, 3-dimensional methodology for imaging the human mitral valve. Leaflet and annular geometry are important determinants of mitral valve stress. Repair techniques that optimize valvular geometry will reduce stress and potentially increase repair durability.

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Background: The effect of mitral leaflet curvature on stress reduction is an important mechanism in optimizing valve function. We hypothesize that annuloplasty ring shape could directly influence leaflet curvature and, potentially, repair durability. We describe an echocardiographically based methodology for quantifying mitral valve geometry and its application to the characterization of ovine mitral valve geometry before and after implantation of an annuloplasty ring.

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Background: Reperfusion therapy for myocardial infarction is currently the most effective means for limiting early and late mortality. We sought to elucidate how reperfusion influences remodeling strains in the infarct, borderzone, and remote myocardial regions. Understanding the effects of reperfusion on regional remodeling will help to evaluate and optimize emerging treatments for patients who do not achieve effective reperfusion after myocardial infarction.

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Background: Ischemic mitral regurgitation results from a variable combination of annular dilatation and remodeling of the subvalvular apparatus. Current surgical techniques effectively treat annular dilatation, but methods for addressing subvalvular remodeling have not been standardized. An effective technique for determining the extent of subvalvular remodeling could improve surgical results by identifying patients who are unlikely to benefit from annuloplasty alone.

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Objectives: : Leaflet and annular geometry are important determinants of mitral valve (MV) stress. Repair techniques which optimize valvular geometry will reduce stress and potentially increase repair durability. The development of such procedures will require image processing methodologies that provide a quantitative description of three-dimensional valvular geometry.

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Objective: Finite-element analysis demonstrates that the nonplanar shape of the mitral annulus diminishes mitral leaflet stress. It has therefore been postulated that repair with annuloplasty rings that maintain the nonplanar shape of the annulus could increase repair durability. Although the global nonplanarity of the mitral annulus has been adequately characterized, design of such a ring requires a quantitative description of regional annular geometry.

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Background: The mammalian mitral annulus is saddle shaped. Experimental studies have shown that loss of saddle shape occurs in ischemic mitral regurgitation. However, neither the temporal pattern of global annular remodeling nor the geometric pattern of regional annular remodeling has been described.

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Background And Aim Of The Study: Left ventricular adaptation to chronic volume overload results in dramatic changes in ventricular geometry and hemodynamics. These changes are reflected in alterations in mechanical load and, eventually, contractile function.

Methods: The study included 17 patients undergoing clinically driven invasive evaluation for mitral regurgitation (MR).

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Objective: Ischemic mitral regurgitation (IMR) results from a variable combination of annular dilatation and remodeling of the subvalvular apparatus. Current surgical techniques effectively treat annular dilatation, but methods for addressing subvalvular remodeling have not been standardized. An effective technique for determining the extent of subvalvular remodeling could improve surgical results by identifying patients who are unlikely to benefit from annuloplasty alone.

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Objectives: The application of repair techniques to treat mitral valve incompetence has increased progressively during the past 20 years. Unfortunately, recent reports have demonstrated the longevity of these repairs to be less than previously believed. Most repair failures are stress related.

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