bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface Modified Cardiopulmonary Bypass Circuits: Modifying the Inflammatory Response
Authors: Rubens F. D. , Mesana T.
Published: June 2007

As a consequence of an aging population demographic, now more than ever, researchers in cardiac surgery must focus on means to improve the methods and technologies related to cardiopulmonary bypass. This review presents a classification of the currently available options for biomaterial modification for cardiopulmonary bypass circuits. Hypotheses are given relating the mechanism of action by which some of these surfaces afford improved biocompatibility. Finally, nonpharmacologic biomaterial-independent strategies for minimizing the effects of cardiopulmonary bypass, such as the use of hemofiltration and leukocyte filtration, and the minimization of the use of cardiotomy suction blood are outlined.
Aprotinin: Antithrombotic and Vasoactive Mechanisms of Action
Authors: Landis R. Clive
Published: June 2007

Aprotinin is a serine protease inhibitor that has been in clinical use since the late 1980s to reduce blood loss in patients undergoing cardiopulmonary bypass surgery. Its hemostatic mechanism of action is mediated predominantly through inhibition of plasmin, thus exerting a net antifibrinolytic effect. Compared to other antifibrinolytics, however, aprotinin provides an additional patient benefit at the level of improved platelet function and diminished inflammatory response to bypass. Recent work on platelets has identified a cell-associated target for aprotinin: the thrombin-receptor, protease-activated receptor 1. Selective blockade of the protease-activated receptor 1 limits thrombin-induced activation and consequent “exhaustion” of platelets in the bypass circuit, while maintaining the hemostatic activity of platelets in the pericardial cavity in response to nonproteolytic agonists, such as collagen, adenosine diphosphate and epinephrine. While no specific cellular receptors have as yet been identified to explain the antiinflammatory and vasoactive properties of aprotinin, awareness is growing that serine protease-sensitive receptors belonging to the protease-activated receptor family (1-4) may represent important aprotinin targets, since these receptors are expressed by all major cells of the vasculature and act as sensors of the coagulation, inflammatory and vasoactive pathways activated by major surgery or trauma. The possibility is discussed that endothelial protease-activated receptor 2, whose natural ligands are trypsin, tryptase and the ternary tissue factor-Vlla-Xa complex, may be targeted by aprotinin.
Myocardial Protection During Minimally Invasive Cardiac Surgery
Authors: Dobkowski Wojciech B.
Published: June 2007

Minimally invasive cardiac surgery or beating heart surgery requires very precise observation, explanation, diagnosis, and proper treatment of all changes in the cardiovascular system that occur during the procedure. A major concern in beating heart surgery is the risk of inducing myocardial ischemia without the circulatory support of cardiopulmonary bypass. Protection of myocardium in different stages of the perioperative period is crucial. The following issues should be taken into consideration: preoperative preparation of the myocardium, providing anesthesia techniques that may help to protect the myocardium, and the use of surgical techniques for myocardial protection. Hemodynamic alterations during dislocations of the heart require understanding of these changes and the effects they have on the myocardium. Proper monitoring during the whole procedure, correlation of all findings with the treatment and therapeutic maneuvers, and excellent cooperation between anesthesiologist and surgeon are essential for myocardial protection. New pharmacologic methods, some experimental, should be considered in near future for myocardial protection during beating heart surgery.
Anesthetic Considerations for Adult Cardiac Surgery Patients with Congenital Heart Disease
Authors: Heggie Jane , Poirer Nancy , Williams William G. , Karski Jacek
Published: June 2007

The number of adults with congenital heart disease surviving into adulthood is increasing. The proportion of adults undergoing revision of a previous repair is increasing in comparison to those that present for a palliative or curative operation. At the Toronto Congenital Cardiac Centre for Adults, 528 patients underwent cardiac surgery between January 1, 1992 and December 31, 2001. The anesthetic management of the surgical correction of simple and complex congenital heart lesions includes general physiologic considerations such as dysrhythmias, hypoxemia, polycythemia, and pulmonary hypertension. Palliative shunts from early childhood have anatomical and physiologic implications for the adult. Preparation for the operating room and postoperative care are natural extensions of the anesthetic management of the surgical correction of the congenital heart lesions. Anesthetic management of septal lesions in the interventional suite and operating room is discussed. Complex lesions such as tetralogy of Fallot, transposition of the great arteries, Glenn anastomosis, and the Fontan operation are reviewed. The anesthetic management of these patients is rewarding but impossible without an integrated team approach involving cardiologists, surgeons, perfusionists, and nursing staff.
Common Pitfalls in Anesthesia for Noncardiac Thoracic Surgery
Authors: Anagnostou Jonathan M.
Published: June 2007

Over the past few decades, major surgical procedures involving the thorax have become commonplace at most larger medical facilities. Advances in perioperative care have allowed surgeons to perform increasingly complex procedures. These procedures are being performed on more seriously ill patients who are at increased risk for significant complications. Recent advances should help the anesthesiologist avoid some of the pitfalls in managing these complex patients. Preoperative assessment aids in the identification of patients at highest risk for intraoperative and postoperative events. Particular attention is given to myasthenia gravis, as thymectomy is among the most common surgical procedures that are performed in these patients. Aggressive pain control techniques, including neuraxial opioids and patient-controlled analgesia, where appropriate, not only improve patient comfort but can improve postoperative pulmonary function. Advances in techniques for providing one-lung ventilation allow the anesthesiologist more options to individualize management for each clinical scenario. Careful fluid management may help to minimize the risk of postoperative pulmonary complications. A basic understanding of video-assisted thoracic surgery should help the anesthesiologist provide optimal surgical conditions and perioperative care. Recent advances demand a greater role for the anesthesiologist if the best outcomes are to be achieved in patients undergoing thoracic procedures.
Endothelial and Microvascular Function
Authors: Striimper Danja , Durieux Marcel , Roekaerts Paul
Published: June 2007

The endothelium is more than just a passive vessel lining. New advances have revealed and expanded the multifactorial role of the endothelium in the homeostatic regulation of the microvasculature, including control of primary hemostasis, blood coagulation and fibrinolysis, platelet and leukocyte interactions with the vessel wall, lipoprotein metabolism, presentation of histocompatibility antigens, regulation of vascular tone and growth, and regulation of blood pressure. It possesses numerous receptors and releases compounds that affect the regulation of vascular tone and contribute to vascular permeability. Many crucial vasoactive endogenous compounds are formed in the endothelial cells to control the functions of vascular smooth muscle cells and circulating blood cells. Gap junctions facilitate the exchange of metabolites, ions, and other messenger molecules among endothelial cells and smooth muscle cells, and regulate cell growth. Among the numerous regulatory systems affecting microvascular function are the cholinergic and adrenergic (α1, α2, and β) systems. Flow-metabolism coupling is affected by a variety of signaling systems, including adenosine, oxygen, carbon dioxide, lactate, nitric oxide, and others. Agents such as the angiotensin system and endothelin, as well as others, play a role in autoregulation (maintenance of constant flow in the face of changing pressure). All of these are discussed in detail.
Angiogenesis: Basic Mechanisms and Clinical Applications
Authors: Chhokar Vikram , Tucker Amy L.
Published: June 2007

The development and maintenance of an adequate vascular supply is critical for the viability of normal and neoplastic tissues. Angiogenesis, the development of new blood vessels from preexisting capillary networks, plays an important role in a number of physiologic and pathologic processes, including reproduction, wound repair, inflammatory diseases, and tumor growth. Angiogenesis involves sequential steps that are triggered in response to angiogenic growth factors released by inflammatory, mesenchymal, or tumor cells that act as ligands for endothelial cell receptor tyrosine kinases. Stimulated endothelial cells detach from neighboring cells and migrate, proliferate, and form tubes. The immature tubes are subsequently invested and stabilized by pericytes or smooth muscle cells. Angiogenesis depends upon complex interactions among various classes of molecules, including adhesion molecules, proteases, structural proteins, cell surface receptors, and growth factors. The therapeutic manipulation of angiogenesis targeted against ischemic and neoplastic diseases has been investigated in preclinical animal models and in clinical trials. Proangiogenic trials that have stimulated vessel growth in ischemic coronary or peripheral tissues through expression, delivery, or stimulated release of growth factors have shown efficacy in animal models and mixed results in human clinical trials. Antiangiogenic trials have used strategies to block the function of molecules critical for new vessel growth or maturation in the treatment of a variety of malignancies, mostly with results less encouraging than those seen in preclinical models. Pro-and antiangiogenic clinical trials demonstrate that strategies for optimal drug delivery, dosing schedules, patient selection, and endpoint measurements need further investigation and refinement before the therapeutic manipulation of angiogenesis will realize its full clinical potential.
Overview of Heparin and Protamine Management and Dosing Regimens in Pediatric Cardiac Surgical Patients
Authors: Oliver William C.
Published: June 2007

Compared with adults, infants and children who undergo cardiopulmonary bypass for cardiac surgery present with a myriad of anticoagulation considerations. Inadequate anticoagulation during cardiopulmonary bypass may cause “subclinical” or “overt” thrombosis, while effective anticoagulation decreases excessive bleeding and transfusions. Current strategies for heparinization and its neutralization in pediatric patients undergoing congenital heart repair requiring cardiopulmonary bypass are examined. The coagulation system of the neonate and infant is immature and is further weakened by congenital heart disease. Changes in coagulation and fibrinolytic activity occur during cardiopulmonary bypass as a result of hemodilution and exposure of the blood to the extracorporeal circuit. Adequate anticoagulation is essential to minimize the thrombin generation that will result. The extent of excessive thrombin formation in pediatric patients undergoing cardiopulmonary bypass is better appreciated today than in the past, but no controlled study defines the optimal dose or technique for heparin dosing in these patients. Heparin concentration may even fall to 1.5 U/mL during cardiopulmonary bypass. However, the activated clotting time and heparin concentration correlate poorly. The ideal method to achieve adequate thrombin inhibition is unknown. Additionally, the dangers of excessive protamine are becoming more apparent. Heparin continues to be the most effective agent to achieve anticoagulation and protamine the most effective agent to neutralize it. A technique for heparin and protamine dosing with determination of heparin concentrations, may remove many variables associated with pediatric cardiac surgery that requires cardiopulmonary bypass and may provide clinicians with new therapies to achieve better anticoagulation for patients and consequently better outcomes.
Glucose Tolerance Testing in Patients Scheduled for Cardiovascular Surgery
Authors: Hoekstra Joost B. L. , Holleman Frits , DeVries Hans
Published: June 2007

Diabetes and impaired glucose tolerance are largely under-diagnosed in patients with acute atherosclerotic events. This glucose-unawareness is an obstacle for aggressive treatment in these patients. It is suggested to check fasting glucose levels in patients scheduled for cardiovascular surgery and to give intensive insulin therapy perioperatively if fasting glucose levels are greater than 7.0 mmol/L (126 mg/dL). If fasting glucose levels are not elevated an oral glucose tolerance test should be considered so that unknown diabetes can be detected and treated.
Beta-Blockade in the Perioperative Period: Where Do We Stand After All the Trials?
Authors: London Martin J.
Published: June 2007

Perioperative myocardial infarction following noncardiac surgery is a complex process with a variety of proposed etiologic factors. Perioperativeb-blockade has been reported to reduce perioperative myocardial infarction and cardiac death, with possible direct effects on longer-term outcome, particularly after vascular surgery. Despite two high-profile studies that have pushed this topic into the mainstream of medicine, the number of patients studied and outcomes observed remains limited, especially for a therapy recommended for widespread adoption in millions of patients globally. Observational analyses, small meta-analyses, and newer randomized trial data (primarily in abstract format) suggest the therapy is of benefit in high-risk patients, whereas in patients at intermediate or low risk, it is either mildly efficacious or neutral in effect. Adverse effects appear to be limited to the expected primary hemodynamic side effects of bradycardia and hypotension, although a suggestion of increased mortality has been reported in one observational analysis in the lowest-risk group.b-Blockade may be associated with reduction in length of stay and reduced analgesic requirements, although these effects remain controversial. A single mega-trial being conducted outside of the United States with a target goal of 10,000 patients is ongoing and promises to provide definitive data within the next few years. Ongoing research into various etiologies of perioperative myocardial infarction and other medications with potential efficacy in this setting, including the important antiplatelet agents, must also be considered in developing recommendations for widespread adoption of perioperativeb-blockade.
Protecting the Heart with Cardiac Medication in Patients with Left Ventricular Dysfunction Undergoing Major Noncardiac Vascular Surgery
Authors: Feringa Harm H. H. , Bax Jeroen J. , Schouten O. , Poldermans D.
Published: June 2007

Patients with left ventricular dysfunction who are undergoing major noncardiac vascular surgery are at increased risk of adverse postoperative events. We sought to evaluate whether perioperative medication use, including angiotensin-converting enzyme (ACE) inhibitors,b-blockers, statins, and aspirin, was associated with a reduced incidence of postoperative in-hospital mortality in these high-risk patients. The study enrolled 511 patients with left ventricular dysfunction (left ventricular ejection fraction <30%) who were undergoing major noncardiac vascular surgery. Cardiac risk factors and medication use were noted before surgery. Preoperative dobutamine stress echocardiography (DSE) was performed to identify patients with stress-induced myocardial ischemia. The end point was postoperative in-hospital mortality. Univariate and multivariate logistic regression analyses were performed to evaluate the relation between perioperative medication use and mortality. The mean age of the study population was 64 ± 11 years, and 75% were men. Perioperative use of ACE inhibitors, b-blockers, statins, and aspirin was recorded in 215 (48%), 139 (27%), 107 (21%), and 125 patients (24%), respectively. Stress-induced myocardial ischemia occurred in 82 patients (16%). Sixty-four patients (13%) died. Perioperative use of ACE inhibitors (odds ratio [OR], 0.33; 95% confidence interval [CI], 0.12-0.91), b-blockers (OR, 0.03; 95% CI, 0.01-0.26), statins (OR, 0.06; 95% CI, 0.01-0.53), and aspirin (OR, 0.13; 95% CI, 0.03-0.55), was significantly associated with a reduced incidence of mortality, after adjusting for cardiac risk factors and DSE results. In conclusion, the present study showed that the perioperative use of ACE inhibitors,b-blockers, statins, and aspirin is independently associated with a reduced incidence of in-hospital mortality in patients with left ventricular dysfunction who are undergoing major noncardiac vascular surgery.
Intravenous Anesthesia for the Patient with Left Ventricular Dysfunction
Authors: Bovill J. G.
Published: June 2007

Patients with heart failure have a diminished cardiac reserve capacity that may be further compromised by anesthesia. In addition to depression of sympathetic activity, most anaesthetics interfere with cardiovascular performance, either by a direct myocardial depression or by modifying cardiovascular control mechanisms. Etomidate causes the least cardiovascular depression. It is popular for induction of anesthesia in cardiac-compromised patients; however, it is not suitable for maintenance of anesthesia because it depresses adrenocortical function. Ketamine has a favorable cardiovascular profile related to central sympathetic stimulation and inhibition of neuronal catecholamine uptake. These counteract its direct negative inotropic effect. In patients with a failing myocardium, however, the negative inotropic effects may be unmasked, resulting in deterioration in cardiac performance and cardiovascular instability. Propofol is the most popular intravenous anesthetic for maintenance of anesthesia. It does have a negative inotropic effect, but the net effect on myocardial contractility is insignificant at clinical concentrations, probably because of a simultaneous increase in the sensitivity of the myofilaments to Ca2+. Propofol protects the myocardium against ischemiareperfusion injury, an action derived from its antioxidant and free-radical-scavenging properties as well as the related inhibition of the mitochondrial permeability transition pore. For intravenous anesthesia, propofol is always combined with an opioid. Opioids have relatively few cardiovascular side effects and, in particular, do not cause myocardial depression. Indeed, they are cardioprotective, with antiarrhythmic activity, and induce pharmacologic preconditioning of the myocardium by a mechanism similar to the inhalational anesthetics.
The Standard TEE Examination: Procedure, Safety, Typical Cross-Sections and Anatomic Correlations, and Systematic Analysis
Authors: Flachskampf Frank A.
Published: June 2007

Multiplane transesophageal echocardiography (TEE) is a semiinvasive, very low-risk imaging procedure utilizing the upper gastric and esophageal echo windows to image the heart with the use of high-frequency transducers. It allows for high spatial resolution and access to structures that are routinely not well seen by transthoracic echocardiography, such as the left atrial appendage, the thoracic aorta, and the pulmonary veins, or where transthoracic imaging may be insufficient to answer a specific question, such as the presence of small vegetations, endocarditic abscesses, abnormalities of the interatrial septum, and others. Another important indication is the ventilated patient or the patient in the operating room, where transthoracic echocardiography is unrewarding or impossible. A particular role has emerged for TEE for identifying candidates for mitral valve repair by providing detailed functional and morphologic information on the diseased valve and by checking intraoperatively the results of surgery. A set of cross-sections, defined by anatomic landmarks, has been compiled, which can be systematically sought, evaluated, and modified according to the clinical question in order to extract the maximal information from TEE.
Evaluation of Mitral Regurgitation
Authors: Troianos Christopher A. , Konstadt Steven
Published: June 2007

Transesophageal echocardiography (TEE) provides high-resolution images of the mitral valve apparatus, permitting detailed evaluation of its structure and function. Mitral valve evaluation is invaluable during mitral valve repair surgery, providing insight into the mechanism of valve dysfunction and formulation of a plan for repair. TEE provides immediate detection of inadequate repair after bypass and allows correction during the same operative setting. Intraoperative TEE is a valuable tool for improving patient outcome and offers the cardiovascular anesthesiologist a role in perioperative surgical decisions.
Evaluation of Prosthetic Heart Valves by Transesophageal Echocardiography: Problems, Pitfalls, and Timing of Echocardiography
Authors: Van den Brink Renee B. A.
Published: June 2007

Transesophageal echocardiography (TEE) is especially suitable for examination of prosthetic valves because of the proximity of the esophagus to the heart and absence of interference with lungs and ribs. This article reviews normal and abnormal morphologic characteristics of prosthetic valves such as spontaneous echocontrast, microbubbles, strands, sutures, vegetations or thrombus. Doppler echocardiographic characteristics of normal and pathologic prosthetic valve function and the management of prosthetic valve pathology is discussed. Physicians taking care of patients with prosthetic valves should be familiar with the characteristics of normal and abnormally functioning prosthetic valves.
Management of High-Risk Perioperative Systems
Authors: Dain Steven
Published: June 2007

The perioperative system is a complex system that requires people, materials, and processes to come together in a highly ordered and timely manner. However, when working in this high-risk system, even well-organized, knowledgeable, vigilant, and well-intentioned individuals will eventually make errors. All systems need to be evaluated on a continual basis to reduce the risk of errors, make errors more easily recognizable, and provide methods for error mitigation. A simple approach to risk management that may be applied in clinical medicine is discussed.
Transesophageal Echocardiography in the Intensive Care Unit
Authors: Karski Jacek M.
Published: June 2007

Transesophageal echocardiography provides unique diagnostic capabilities, allowing for a very precise look at the structure and hemodynamics of the human heart. It is minimally invasive and portable, and quickly diagnoses sudden hemodynamic changes in intensive care patients. It provides invaluable and precise information about myocardial dysfunction and intracardiac volume status. It can diagnose dynamic left ventricular outflow obstruction, infrequent but serious complication of aortic valve replacement, septal myectomy, or mitral valve repair. Transesophageal echocardiography examination can exclude cardiac tamponade and intracardiac source of embolization, and it offers the ability to visualize native or prosthetic valves and assesses their function in the postoperative period. It is helpful in diagnosing endocarditis and the presence of intracardiac masses. In the diagnosis of blunt chest trauma, transesophageal echocardiography offers a fast and safe look at ascending and descending aorta and pericardial effusion, facilitating future decisions about patient management. In patients with postoperative hypoxia, it can exclude intracardiac shunt. Finally, in heart transplants or in managing patients with mechanical heart assist devices, transesophageal echocardiography is an invaluable tool in assessing progress of treatment and complications arising from the procedures. With the introduction of multiplane transesophageal echocardiography probes, technology, and experienced personnel, transesophageal echocardiography becomes the extension of the physical examination in the intensive care unit. This example is one of only a few whereby technology brings the physician closer to the patient.
Hemostasis and Glycemic Control in the Cardiac Surgical Patient
Authors: Slaughter Thomas F.
Published: June 2007

The Centers for Disease Control and Prevention estimate that 6% of the US population meets diagnostic criteria for diabetes mellitus, with at least one third of this group being undiagnosed. A majority of adult blindness, renal insufficiency, and limb amputation may be directly attributed to diabetes. Although the incidence of type 1, autoimmune-mediated diabetes remains relatively stable, increasing age, physical inactivity, and obesity have produced explosive growth in insulin resistance and type 2 diabetes. A direct association between diabetes and atherothrombotic disease remains indisputable. However, recent data further suggest that even minor elevations of fasting plasma glucose, in “nondiabetic” subjects, increase cardiovascular risk. Alterations in hemostasis may play an important contributory role. Both hyperglycemia and hyperinsulinemia induce prothrombotic characteristics, including overexpression of vascular endothelial plasminogen activator inhibitor-1 (PAI-1), down-regulation of fibrinolysis, elevation of plasma coagulation proteins (ie, fibrinogen, factor VII, factor X), and enhanced platelet activation. Furthermore, endothelial dysfunction—characterized by an inflammatory phenotype—commonly accompanies diabetes. Given data supporting prothrombotic potential of both acute and chronic hyperglycemia, aggressive perioperative glucose control appears imperative.
Angiogenesis for the Treatment of Inoperable Coronary Disease: The Future
Authors: Sellke Frank W. , Laham Roger , Suuronen Erik J. , Ruel Marc
Published: June 2007

Improved treatment options and better management of cardiovascular risk factors have resulted in improved outcomes for patients suffering from severe coronary artery disease. However, coronary artery disease may be of such a diffuse and severe manner that repeated attempts at catheter-based interventions and coronary artery bypass grafting may be unsuccessful at restoring normal myocardial blood flow. It is the goal of therapeutic angiogenesis to restore perfusion to chronically ischemic myocardium using protein growth factors, gene therapy, or, more recently, cell-based therapy, without intervening on the epicardial coronary arteries. However, angiogenesis has not yet provided significant clinical benefit and is still reserved as an experimental treatment for patients who have failed conventional therapies. Once potential endogenous inhibitors of vascular development can be modified, angiogenesis may become more useful for therapeutic purposes. It is hoped that angiogenesis for therapeutic purposes will one day effectively re-create the potent natural processes of vascularization that every human being undergoes during growth and development and become a major modality for the treatment of coronary artery disease.
Systolic Hypertension in Elderly Patients
Authors: Safar Michel E.
Published: June 2007

Pulsatile arterial hemodynamics in cardiovascular diseases indicate that the aortic blood pressure curve may be represented by 2 different phenotypes: one in patients 64 years old and younger and the other in subjects older than 65 years. The 2 blood pressure curves may have exactly the same mean arterial pressure (ie, the same cross-sectional area under the curve) but quite different shapes. In older subjects, systolic blood pressure and pulse pressure are higher, whereas diastolic blood pressure is lower than in younger subjects.
A Commentary on Clinical Trials in Chronic Heart Failure
Authors: Poole-Wilson Philip A , Lyon Alexander R. , Jacques Adam M.
Published: June 2007

Heart failure is a common condition and becoming more common. Many treatments have been evaluated in large clinical trials during the last few decades. These trials can be criticized but do provide an evidence base for treatment, probably greater than for most other clinical conditions. Weaknesses exist in relation to age, ejection fraction, and gender. Most trials have included patients 10 years younger than those in the general population. There is little evidence for efficacy in patients with a near normal ejection fraction. Few women have been included in trials.
Free Fatty Acids and Postischemic Myocardial Function
Authors: van der Vusse Ger J. , van Bilsen Marc
Published: June 2007

This review highlights the changes in fatty acid homeostasis in the postischemic heart. The impact of restoration of flow (reperfusion) after an ischemic episode on both structural fatty acids (ie, incorporated in phospholipids, the building blocks of cellular membranes) and fatty acids, serving as energy donors by mitochondrial oxidation, are discussed. Attempts to interfere with cardiac fatty acid homeostasis to prevent loss of cardiac function or to restore cardiac performance after reperfusion is also discussed.
Genetic Influences on Cerebral Outcome After Cardiac Surgery
Authors: Grocott Hilary P.
Published: June 2007

Just as the influence of genetic variation on patient outcomes is being discussed in many other areas of medicine, so too are its effects on cerebral outcome after cardiac surgery now being described. Whereas early studies focused on neurocognitive outcome, where the single nucleotide polymorphisms of APOE4 and PLA2 were the first investigated genetic targets, stroke is now being elaborated on with related single and multi-gene single nucleotide polymorphisms having been identified. Our work has established key links between post-cardiac surgery stroke and C-reactive protein (3’UTR 1846C/T) and interleukin-6 (-174 G/C) single nucleotide polymorphisms.
The Genetic Determinants of Renal Impairment Following Cardiac Surgery
Authors: Yates Robert B. , Stafford-Smith Mark
Published: June 2007

Cardiac surgery is frequently performed, and acute renal dysfunction is a common adverse event following this procedure. Cardiac surgery-related renal injury independently predicts longer hospital stays and greater rates of morbidity and mortality. Although much work has been completed toward better understanding of this phenomenon, the state of knowledge concerning surgery-related renal injury remains limited. Currently, there is no effective paradigm to identify patients who are at risk for this condition; the specific mechanisms of renal injury during surgery are incompletely understood; and few therapies exist to prevent or treat this phenomenon. To better understand this common clinical problem, recent research has focused on the importance of genetic variability within the physiological and patho-physiological systems that underlie renal dysfunction following cardiac surgery. Emphasizing the importance of using genetics to elucidate molecular mechanisms of this disease, this article reviews the current literature on genetic polymorphisms and post cardiac surgery-related renal dysfunction.
Surrogate Markers for Neurological Outcome in Children After Deep Hypothermic Circulatory Arrest
Authors: Markowitz Scott D. , Ichord Rebecca N. , Wernovsky Gil , Gaynor J. William , Nicolson Susan C.
Published: June 2007

Improved survival for infants with congenital heart disease (CHD) has led to increased focus on the most significant morbidities that are neurodevelopmental. Neurologic injury in neurodevelopmental outcome may have many causes in children with complex CHD undergoing cardiopulmonary bypass and deep hypothermic circulatory arrest, including genetic syndromes, abnormal blood flow patterns, prenatal insults, and hemodynamic instability. Although gross neurological injury can be detected in the perinatal and postoperative period, more subtle injury may not be identified until much later. Disabilities in speech and language, motor skills, and attention deficit disorder are present by school age in up to 50% of the complex CHD population. It is imperative that the mechanisms of these injuries be identified to enable the application of neuroprotective interventions. To facilitate clinical investigation, evaluation of surrogate markers for these longer term “real” outcomes continues. Because some abnormalities may not be detected for years, the evaluation of a surrogate marker takes a long time. Thus, identification of surrogate markers is in its infancy. Serologic proteins, seizures, magnetic resonance findings, cerebral oxygenation, and the neurologic examination have all been studied. Continuing innovation in the use of magnetic resonance imaging techniques and the application of physiologic measures including near-infrared spectroscopy currently pose the greatest potential for advances. This article summarizes the state of the art and an admission about how far we have yet to travel as we strive to make the neurodevelopmental outcomes of patients with CHD comparable to their healthy peers.
Growth Modeling Using Random Coefficient Models: Model Building, Testing, and Illustrations
Authors: Bliese Paul D. , Ployhart Robert E.
Published: June 2007

In this article, the authors illustrate how random coefficient modeling can be used to develop growth models for the analysis of longitudinal data. In contrast to previous discussions of random coefficient models, this article provides step-by-step guidance using a model comparison framework. By approaching the modeling this way, the authors are able to build off a regression foundation and progressively estimate and evaluate more complex models. In the model comparison framework, the article illustrates the value of using likelihood tests to contrast alternative models (rather than the typical reliance on tests of significance involving individual parameters), and it provides code in the open-source language R to allow readers to replicate the results. The article concludes with practical guidelines for estimating growth models.
A Review and Synthesis of the Measurement Invariance Literature: Suggestions, Practices, and Recommendations for Organizational Research
Authors: Vandenberg Robert J. , Lance Charles E.
Published: June 2007

The establishment of measurement invariance across groups is a logical prerequisite to conducting substantive cross-group comparisons (e.g., tests of group mean differences, invariance of structural parameter estimates), but measurement invariance is rarely tested in organizational research. In this article, the authors (a) elaborate the importance of conducting tests of measurement invariance across groups, (b) review recommended practices for conducting tests of measurement invariance, (c) review applications of measurement invariance tests in substantive applications, (d) discuss issues involved in tests of various aspects of measurement invariance, (e) present an empirical example of the analysis of longitudinal measurement invariance, and (f) propose an integrative paradigm for conducting sequences of measurement invariance tests.
A Monte Carlo Study of Missing Item Methods
Authors: Mcdonald Robert A. , Thurston Paul W. , Nelson Mark R.
Published: June 2007

A Monte Carlo simulation methodology was used to examine the effectiveness of five methods for handling missing data in items that comprise summated scales: listwise deletion, item mean substitution, person mean substitution, random number substitution, and regression imputation. Overall, regression imputation was the most effective method in reproducing psychometric properties of a summated scale and preserving statistical power to detect correlations between the summated scale and other variables. The item mean substitution method yielded biased estimates of the standard deviation of the summated scale. Although list- wise deletion yielded relatively unbiased estimates of the psychometric properties of the summated scale, there were high levels of dispersion in the estimates around the true population values. Furthermore, listwise deletion led to severe reductions in statistical power to detect correlations between the summated scale and other variables.
A Comparison of Approaches to Forming Composite Measures in Structural Equation Models
Authors: Landis Ronald S. , Beal Daniel J. , Tesluk Paul E.
Published: June 2007

A common practice in applications of structural equation modeling techniques is to create composite measures from individual items. The purpose of this article was to provide an empirical comparison of several composite formation methods on model fit. Data from 1, 177 public school teachers were used to test a model of union commitment in which alternative composite formation methods were used to specify the measurement components of the model. Bootstrapping procedures were used to generate data for two additional sample sizes. Results indicated that the use of composites, in general, resulted in improved overall model fit as compared to treating all items as individual indicators. Lambda values and explained criterion variance indicated that this improved model fit was due to the creation of strong measurement models. Implications of these results for researchers using composites are discussed.
Moderated Multiple Regression Tests are Criterion Specific
Authors: Landis Ronald S. , Dunlap William P.
Published: June 2007

This article examines how the ordering of variables impacts conclusions regarding the presence of a significant interactive relationship in moderated multiple regression (MMR). It is argued that whenever the designation of a criterion is arbitrary, researchers should consider performing two MMR analyses: one in which y is treated as the criterion, x the predictor, and m the moderator and a second in which x is the criterion and y the predictor. An example illustrates that these analyses are not symmetrical and that a significant interaction may be observed in one case but not the other. A simulation further illustrates conditions under which such effects are likely to occur. Implications for researchers studying interactions are discussed.
Factor Analysis of Importance Ratings in Job Analysis: Note on the Misinterpretation of Cranny and Doherty (1988)
Authors: Johnson Jeff W.
Published: June 2007

An article by Cranny and Doherty has inadvertently created a common perception among researchers that factor analysis should never be applied to importance ratings collected in a job analysis. The author argues that factor analysis of job analysis importance ratings is appropriate under the following conditions: (a) meaningful differences exist between jobs or positions analyzed, (b) each variable has some interrater agreement within jobs and some variance across jobs or positions, and (c) the research objective is to find a set of factors that reflect shared patterns of the extent to which the tasks, behaviors, or characteristics are relevant to different positions. Illustrative examples are presented of situations in which within-job correlations and variances have little effect on the factor structure across jobs.
Conceptualizing and Measuring Professional and Administrative Models of Organizing
Authors: Bunderson J. Stuart , Lofstrom Shawn M. , Van De Ven Andrew H.
Published: June 2007

This article introduces a typology and evaluates a set of measures for studying professional and administrative models of organizing. Four mental models of organizing are contrasted: the bureaucratic system model, the market enterprise model, the professional group model, and the community service model. These organizing models reflect the internal and external partitioning of administrative and professional rationality. This article describes the development of an instrument for measuring the extent to which individuals perceive that their organization does or should emphasize each of these four models. Data obtained from repeated administrations of this survey instrument in a managed health care organization support the convergent and discriminant validity of the proposed measures, as well as their temporal stability and generalizability across occupational groups. An analysis of relationships between these constructs and theoretically related constructs provides preliminary evidence for their value in the analysis of complex organizations.
An Additional Rating Method for Journal Articles in the Field of Management
Authors: Kacmar K. Michele , Whitfield J. Michael
Published: June 2007

A frequently used method for determining the influence rating of a journal article is the citation count. This article argues that simply counting citations may not be sufficient. Instead, to gain a fuller understanding of the influence of an article on future research, the importance of the cited reference to the citing article should be examined. To illustrate this suggested method, a sample of articles from Academy of Management Review and Academy of Management Journal was analyzed. Results indicated that the vast majority of the citing articles simply listed the focal articles as references instead of using them as an integral component (i.e., a test of the ideas) of the study. Augmenting the traditional citation-counting approach with the proposed technique should produce a more accurate picture of the influence of an article on the field.
Attitudes toward Surveys: Development of a Measure and Its Relationship to Respondent Behavior
Authors: Rogelberg Steven G. , Fisher Gwenith G. , Maynard Douglas C. , Hakel Milton D. , Horvath Michael
Published: June 2007

Attitudes toward surveys were conceptualized as having two relatively independent components: feelings about the act of completing a survey, called survey enjoyment, and perceptions of the value of survey research, called survey value. After developing a psychometrically sound measure, the authors examined how the measure related to respondent behaviors that directly impact the quality and quantity of data collected in surveys. With the exception of a response distortion index, survey enjoyment was generally related to all the respondent behaviors studied (item response rates, following directions, volunteering to participate in other survey research, timeliness of a response to a survey request, and willingness to participate in additional survey research). Survey value was related to item response rates, following directions, and willingness to participate in additional survey research. A respondent motivation and intentions explanation is provided. Although the identified effect sizes were generally small, a number of practical implications emerge and are discussed.
Consideration of the Incomplete Block Design for Policy-Capturing Research
Authors: Graham Mary E. , Cable Daniel M.
Published: June 2007

This article introduces and urges consideration of the incomplete block design for policy-capturing research. The authors compare incomplete block designs with full factorial and fractional factorial designs along several dimensions, including survey length, analysis limitations, and impact on study participants. An initial empirical investigation of an incomplete block design and a full factorial design is performed in a policy-capturing study of 183 job seekers. As predicted, the two designs generated equivalent results on the main effects and most interactions; however, the designs yielded divergent results on some interactions. Study participants who received the incomplete block design were more positive about the survey length and experienced less stress and exhaustion than those receiving the full design. The authors discuss how methodologists might examine and compare policy-capturing designs in future research.
Using Internet/Intranet Web Pages to Collect Organizational Research Data
Authors: Stanton Jeffrey M. , Rogelberg Steven G.
Published: June 2007

Wide availability of networked personal computers within organizations has enabled new methods for organizational research involving presentation of research stimuli using Web pages and browsers. The authors provide an overview of the technological challenges for collecting organizational data through this medium as a springboard to discuss the validity of such research and its ethical implications. A review of research comparing Web browser–based research with other administration modalities appears to warrant guarded optimism about the validity of these new methods. The complexity of the technology and researchers’ relative unfamiliarity with it have created a number of pitfalls that must be avoided to ensure ethical treatment of research participants. The authors highlight the need for an online research participants’ bill of rights and other structures to ensure successful and appropriate use of this promising new research medium.
The Effects of Model Parsimony and Sampling Error on the Fit of Structural Equation Models
Authors: Cheung Gordon W. , Rensvold Roger B.
Published: June 2007

The fit between a structural equation model and a data set is operationalized as the value of goodness-of-fit indices. The discrepancy between the estimated value and the value indicating perfect fit has three sources: misspecification, error arising from theoretical parsimony in the description of the model (parsimony error), and sampling error. Misspecification, which represents a disparity between “realworld” relationships and relationships in the model, is the most important source of error for researchers. It cannot be accurately assessed, however, unless parsimony error and sampling error are taken into account. Parsimony error occurs in measurement models when secondary relationships are excluded. Secondary relationships are defined here as secondary factor loadings and error term correlations that have small values, no theoretical bases, and no substantive meaning. A simulation was conducted to examine the effects of parsimony error on perfect measurement models and to establish appropriate criteria for model fit when parsimony error is present.
Estimation of Interaction Effects in Organization Studies
Authors: Aguinis Herman
Published: June 2007

This article introduces ORM’s feature topic on interaction effects in organization studies. First, it defines interaction effects. Second, it discusses the criticality and pervasiveness of interaction effects in organization studies. Third, it describes the three articles included in this feature topic. Finally, it addresses needs for future research regarding the estimation of interaction effects in organization studies.
The Effectiveness of Methods for Analyzing Multivariate Factorial Data
Authors: Mcdonald Robert A. , Seifert Charles F. , Lorenzet Steven J. , Givens Susan , Jaccard James
Published: June 2007

A Monte Carlo simulation was used to examine the effectiveness of univariate analysis of variance (ANOVA), multivariate analysis of variance (MANOVA), and multiple indicator structural equation (MISE) modeling to analyze data from multivariate factorial designs. The MISE method yielded downwardly biased standard errors for the univariate parameter estimates in the small sample size conditions. In the large sample size data conditions, the MISE method outperformed MANOVA and ANOVA when the covariate accounted for variation in the dependent variable and variables were unreliable. With multivariate statistical tests, MANOVA outperformed the MISE method in the Type I error conditions and the MISE method outperformed MANOVA in the Type II error conditions. The Bonferroni methods were overly conservative in controlling Type I error rates for univariate tests, but a modified Bonferroni method had higher statistical power than the Bonferroni method. Both the Bonferroni and modified methods adequately controlled multivariate Type I error rates.