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Biomedical subjects

Thomas G Gleason

Publications and source records attributed to Thomas G Gleason.

At least 19 recordsLinked to original sources
PubMed2007

Reduction of surgical mortality and morbidity in diabetic patients undergoing cardiac surgery with a combined intravenous and subcutaneous insulin glucose management strategy.

OBJECTIVE: To determine if glucose management in postcardiothoracic surgery patients with a combined intravenous (IV) and subcutaneous (SC) insulin regimen reduces mortality and morbidity in patients with diabetes and stress-induced hyperglycemia. RESEARCH DESIGN AND METHODS: Retrospective review of 614 consecutive patients who underwent cardiothoracic (CT) surgery in 2005 was performed to evaluate the incidence and treatment of postoperative hyperglycemia and operative morbidity and mortality. Hyperglycemic patients (glucose >6.05 mmol/l) were treated with IV insulin in the intensive care unit (ICU) followed by SC insulin (outside ICU). Subgroup analysis was performed on 159 coronary artery bypass grafting (CABG)-only patients. RESULTS: Among all CT surgeries, patients with a preoperative diagnosis of diabetes had higher rates of postoperative mortality (7.3 vs. 3.3%; P = 0.03) and pulmonary complications (19.5 vs. 11.6%; P = 0.02) but had similar rates of infections and cardiac, renal, and neurological complications on univariate analysis. However, on multivariate analysis, a preoperative diagnosis of diabetes was not a significant factor in postoperative mortality or pulmonary complications. In CABG-only patients, no significant differences were seen in outcomes between diabetic and nondiabetic patients. Independent of diabetic status, glucose > or =11 mmol/l on ICU admission was predictive of higher rates of mortality and renal, pulmonary, and cardiac postoperative complications. CONCLUSIONS: A combination of IV insulin (in the ICU) and SC insulin (outside the ICU), a less costly and less nursing-intensive therapy than 3 days of IV insulin postoperatively, results in a reduction of the increased surgical morbidity and mortality in diabetic patients after CT surgery.

Aged↗
PubMed2006

Human degenerative valve disease is associated with up-regulation of low-density lipoprotein receptor-related protein 5 receptor-mediated bone formation.

OBJECTIVES: The goal of this research was to define the cellular mechanisms involved in myxomatous mitral valve disease and calcific aortic valve disease and to redefine the term degenerative valve disease in terms of an active cellular biology. BACKGROUND: "Degenerative" valvular heart disease is the primary cause of regurgitant and stenotic valvular lesion in the U.S. However, the signaling pathways are not known. We hypothesize that valve degeneration occurs due to an osteoblastic differentiation process mediated by the low-density lipoprotein receptor-related protein 5 (Lrp5) signaling pathway to cause valve thickening. METHODS: We examined human diseased valves: myxomatous mitral valves (n = 23), calcified tricuspid aortic valves (n = 27), calcified bicuspid aortic valves (n = 23), and control tissue from mitral and aortic valves (n = 40). The valves were examined by reverse transcriptase-polymerase chain reaction, Western blot, and immunohistochemistry for signaling markers important in osteoblast differentiation: Sox9 and Cbfa1 (transcription factors for osteoblast differentiation); Lrp5 and Wnt3 (osteoblast differentiation signaling marker), osteopontin and osteocalcin (osteoblast endochrondral bone matrix proteins), and proliferating cell nuclear antigen (a marker of cell proliferation). Cartilage development and bone formation was measured by Alcian blue stain and Alizarin red stain. Computed Scano MicroCT-40 (Bassersdorf, Switzerland) analysis measured calcium burden. RESULTS: Low-density lipoprotein receptor-related protein 5, osteocalcin, and other osteochrondrogenic differentiation markers were increased in the calcified aortic valves by protein and gene expression (p > 0.001). Sox9, Lrp5 receptor, and osteocalcin were increased in myxomatous mitral valves by protein and gene expression (p > 0.001). MicroCT was positive in the calcified aortic valves and negative in the myxomatous mitral valves. CONCLUSIONS: The mechanism of valvular heart disease involves an endochondral bone process that is expressed as cartilage in the mitral valves and bone in the aortic valves. Up-regulation of the Lrp5 pathway may play a role in the mechanism for valvular heart disease.

Aged↗
PubMed2006

Anterior approach to traumatic mid aortic arch transection.

The majority of nonpenetrating traumatic injuries to the thoracic aorta are fatal. Survivors of aortic transection tend to have injuries occurring at the isthmus. We report a rare, blunt traumatic complete transection of the mid aortic arch between the innominate and left common carotid arteries diagnosed by multidetector computed tomography of the chest. The repair was approached anteriorly and required aortic arch replacement.

Accidents, Traffic↗
PubMed2006

Safety and efficacy of left ventricular assist device support in postmyocardial infarction cardiogenic shock.

BACKGROUND: Cardiogenic shock secondary to acute myocardial infarction (CS-AMI) is the leading cause of death in all acute coronary syndromes. Experience with the use of left ventricular assist devices (LVADs) in patients with CS-AMI is limited. One of the surgical dilemmas when implanting an LVAD into a patient with an acute anterior wall myocardial infarction is the safety of apical cannulation. We present a decade of experience with the use of LVAD with apical cannulation in patients with CS-AMI. METHODS: A retrospective review of the ventricular assist device (VAD) database at the Hospital of the University of Pennsylvania was instituted. RESULTS: From April 1995 to February 2005, 49 patients received LVAD support for CS-AMI (group I). The majority of these patients suffered anterior wall myocardial infarctions. This group of patients was compared with a separate cohort of 61 patients with chronic ischemic cardiomyopathy who received LVAD support (group II). The VAD support successfully bridged 38 (74%) group I patients and 37 (61%) group II patients to heart transplantation. Of the 38 patients transplanted in group I, 33 (87%) were discharged from the hospital. In group II, 36 of the 37 patients transplanted (97%) survived to hospital discharge. The overall in-hospital mortality rates for the series were 33% for group I patients, and 41% for group II patients. CONCLUSIONS: Left ventricular assist device support in patients with CS-AMI is a safe and effective therapy which should be incorporated into the standard treatment paradigm for appropriate patients presenting with this lethal disease.

Female↗
PubMed2006

Utility of left subclavian artery revascularization in association with endoluminal repair of acute and chronic thoracic aortic pathology.

BACKGROUND: A rapidly increasing number of thoracic aortic lesions are now treated by endoluminal exclusion by using stent grafts. Many of these lesions abut the great vessels and limit the length of the proximal landing zone. Various methods have been used to address this issue. We report our experience with subclavian artery revascularization in association with endoluminal repair of acute and chronic thoracic aortic pathology. METHODS: Thirty (43%) of 70 patients undergoing thoracic endovascular stent-graft placement from January 2001 to August 2005 had lesions adjacent to or involving the origin of the subclavian artery. The mean age was 62 years (range, 22-85 years; 63% were men, and 37% were women). This subgroup of 30 patients had indications for repair that included thoracic aortic aneurysm (n = 15), traumatic transection (n = 6), chronic dissection with pseudoaneurysm (n = 5), and acute dissection with intramural hematoma (n = 4). All 30 patients had the subclavian origin covered by the stent graft. In eight cases (27%), no effort was made to revascularize the subclavian artery before or during the endograft placement procedure. Twenty-three (77%) of 30 patients underwent subclavian to carotid artery transposition (n = 21) or bypass (n = 2) before (n = 12; average of 14 days before stent-graft placement), concomitant with (n = 10), or after (n = 1) the endovascular procedure. Physical examination and computed tomography scans were performed after surgery at 1, 6, and 12 months and annually thereafter. The mean follow-up was 18 months (range, 1-51 months). RESULTS: Five acute complications occurred in the eight patients (63%) who had the subclavian artery covered without pre-endograft revascularization and included four patients who experienced stroke (accounting for the only death) and one patient who developed symptomatic subclavian-vertebral steal that necessitated transposition 7 months later. Two (9%) of the 23 patients who had subclavian revascularization experienced left-sided vocal cord palsies, and 1 patient (4%) developed lower extremity paraparesis secondary to spinal cord ischemia. No late endoleaks related to retrograde sac perfusion from the most distal great vessel have been identified in any patient. CONCLUSIONS: Subclavian revascularization procedures can be performed with relatively low risk. Complications are rare, and patient recovery is rapid. Although this is not necessary in all cases, we advocate subclavian to carotid transposition when the aortic lesion is within 15 mm of the left subclavian orifice to prevent type II endoleak or perfusion of a dissected false lumen when the ipsilateral vertebral artery is patent and dominant or when coronary revascularization using an ipsilateral internal mammary artery is anticipated and in cases that necessitate extensive coverage of intercostals that contribute to spinal cord perfusion. Carotid to subclavian artery bypass should be reserved for patients with a patent internal mammary artery conduit perfusing a coronary vessel and should be combined with proximal subclavian ligation.

Acute Disease↗
PubMed2006

Current perspective on aortic valve repair and valve-sparing aortic root replacement.

Aortic valve repair and valve-sparing aortic root replacement are attractive concepts because they offer the possibility of valve competence without structural deterioration due to nonviability and they preclude the need for anticoagulation. Enthusiasm for aortic valve repair has waxed and waned over the past 45 years due in part to the inherent technical difficulties and poor mid-term results. Renewed interest in the concept of aortic valve repair has paralleled the development of valve-sparing aortic root replacement over the last 20 years. A current perspective on aortic valve repair and valve-sparing aortic root replacement is presented in the following review. Historical background, indications for repair, technical considerations, and outcomes data are discussed.

Aortic Valve↗
PubMed2005

Heritable disorders predisposing to aortic dissection.

Heritable disorders of connective tissue often predispose patients to aortic pathology and in particular aortic dissection. The Marfan syndrome, vascular Ehlers-Danlos syndrome, familial forms of thoracic aortic aneurysms or aortic dissection, and bicuspid aortic valve are all examples of heritable disorders that have associated defects affecting the integrity of the aortic wall, posing a risk of both aneurysmal dilation and dissection. The purpose of this review was to outline the phenotypes of the heritable syndromes that predispose to aortic dissection, present a guideline to their management and surveillance, and to offer insight into some of the surgical pitfalls that occur when repairing ascending aortic dissections in these types of patients.

Aortic Dissection↗
PubMed2005

Operative management of ascending aortic dissections.

Surgical management has been the established standard of care for acute ascending aortic dissection (Stanford type A or Debakey type I or II) with a worldwide average operative mortality rate of 23% compared with a 1-month mortality rate of 60% with medical management alone. Improving an institution's operative results depends on the establishment of a comprehensive and specialized team integrating their expertise into a protocol-driven system of care delivery specific for aortic dissections. The operative strategies and techniques for repairing aortic dissections should also be standardized within an institution to optimize outcomes. The primary goals of operative repair of ascending aortic dissection are to restore aortic valvular competency and systemic perfusion, to obliterate false-lumen blood flow, and to prevent rupture, myocardial infarction, stroke, and death. The goals, strategies, and expected outcomes for the operative management of acute ascending aortic dissection are presented.

Aortic Dissection↗
PubMed2005

Chronic descending aortic dissections.

Aortic dissection involving the descending aorta has a predictable and often debilitating course of progressive dilatation that occurs once patients survive the acute phase of the disease. Important factors that impact the rate and degree of dilatation include the persistence of a false lumen channel (and the amount of thrombus), the control of hypertension, and the presence of an underlying connective tissue disorder. The mainstay of management of chronic descending aortic dissections is antihypertensive therapy including beta-blockade until the dissected aorta becomes significantly aneurysmal. Surgical management is recommended at that point. Multiple advances have been made that have improved the results of operative repair of aneurysmal descending aortic dissections including circulation management methodologies, CSF drainage, neurocerebral monitoring, and more recently, endovascular therapies. The presentation, diagnosis and management of chronic descending aortic dissections are discussed.

Aortic Dissection↗
PubMed2004

St. Jude Medical Toronto biologic aortic root prosthesis: early FDA phase II IDE study results.

BACKGROUND: Several biological aortic root replacement techniques have distinct advantages over mechanical composite root replacement including better valvular hemodynamic characteristics and the lack of need for anticoagulation. Current biological root replacement options lack proven long-term durability or are limited by technical or practical concerns. We report the early results from a phase II multicenter clinical trial of the porcine St. Jude Toronto Bioprosthesis with BiLinx (Toronto root). METHODS: 176 Toronto roots were implanted as total aortic root replacement from August 2001 through August 2003. Concomitant cardiac procedures including coronary artery bypass grafting (31%) and ascending aortic replacement (55%) were performed in 74%. Patients were followed clinically and were examined with an echocardiogram at discharge, 6 months, 12 months, and yearly thereafter. Root sizes implanted included 29 mm in 38%, 27 mm in 30%, 25 mm in 20%, 23 mm in 10%, and 21 mm in 2.2%. RESULTS: There are 205 patient years of follow-up through October 2003. Operative mortality was 3.9% (none were valve related) and late mortality was 4%. Operative stroke rate was 1.1% and late stroke rate was 0.6%. Endocarditis developed in 1 patient. Freedom from aortic regurgitation is to date 100% at discharge, 6 months, and 1 year postimplant. Reoperation of the aortic valve/root was not required in any patient. Six-month mean transvalvular gradients for 21-29 mm valves were 12.8, 8.8, 5.3, 4.9, and 4.7 mm Hg, respectively. CONCLUSIONS: Aortic root replacement with the Toronto root is safe and provides superb transvalvular hemodynamics with freedom from anticoagulation. The Toronto root seems widely applicable for all types of aortic root pathology and these early data offer very encouraging results. Long-term follow-up is required.

Adult↗
PubMed2004

Ethnic disparities in outcome from posttransplant infections.

Black transplant recipients have decreased graft survival and increased rejection rates compared with whites. Because increased rejection rates may lead to more immunosuppression in black recipients, ethnic differences may exist for outcomes of posttransplant infectious complications. All episodes of infection between December 1996 and October 1998 on the transplant services at the University of Virginia Health Sciences Center were prospectively evaluated. Parameters recorded included self-designated ethnicity, demographics, APACHE II scores, laboratory and microbiologic data, immunosuppression, episodes of rejection, and outcome measures. Evaluation of 303 episodes of infection demonstrated an increased mortality rate for white compared with black recipients (19% vs. 3%, P = 0.0006) despite having a similar severity of illness (APACHE II score). Among renal transplant recipients, episodes of infection occurring in black recipients (n = 46) were also associated with a decreased mortality rate versus whites (n = 89) (0% vs. 15%, P = 0.006) and shorter mean length of stay (12 +/- 2 vs. 25 +/- 4 days, P = 0.002) despite similar severity of illness and rejection rates. For posttransplant infections in liver transplant recipients, blacks (n = 23) demonstrated a trend toward decreased mortality (9% vs. 26%, P = 0.07) but equal lengths of stay despite similar APACHE II scores, rejection rates, and age. White liver transplant recipients had an increased incidence of viral infections (15% vs. 0%, P = 0.03). All other infecting organisms were similar. The unexpected finding of a significantly decreased rate of mortality associated with posttransplant infections in black recipients remains largely unexplained but may be related to subtle differences in immune response between racial or ethnic groups.

APACHE↗
PubMed2002

Outcome analysis of intraabdominal infection with resistant gram-positive organisms.

BACKGROUND: Although the microbiology of intraabdominal infection has been well described, the role of resistant organisms remains unclear. To evaluate the hypothesis that intraabdominal infections from resistant gram-positive cocci (rGPC) have worse outcomes compared to those with susceptible organisms, patient characteristics and outcomes were compared between these groups. METHODS: Analysis of peritoneal infections was performed on prospectively collected data of all consecutive surgical infections from December 1996 to June 1999 at a university hospital. Intraabdominal infection was defined either by a positive peritoneal cavity culture or on clinical grounds (e.g., abscess), which prompted antimicrobial or surgical therapy. Resistant Staphylococcus and Enterococcus spp. were defined as those strains resistant to oxacillin, gentamicin, or vancomycin. RESULTS: Compared to episodes of intraabdominal infection from susceptible organisms (n = 365), infections due to rGPC (n = 52) were associated with an increased severity of illness (p < 0.0001), longer time from admission to treatment (p < 0.0001), longer duration of therapy (p = 0.008), greater proportion of nosocomial infection (p < 0.0001), increased length of stay (p < 0.0001), and an increased mortality rate (9% versus 23%; p = 0.003). However, comparison of intraabdominal infection with rGPC to a group controlled for severity of illness demonstrated a prolonged time from admission until treatment and longer duration of hospitalization but a similar mortality rate between groups (17% versus 23%; p = 0.46). CONCLUSION: Intraabdominal infection with rGPC is an indicator of poor prognosis and severe illness. Although not an independent predictor of mortality, the significantly increased duration of therapy and prolonged duration of hospitalization may have considerable economic impact.

Abdomen↗
PubMed2002

Effect of changes in surgical practice on the rate and detection of nosocomial infections: a prospective analysis.

The practice of surgery is being performed increasingly on an outpatient basis. How these changes have influenced the nosocomial infection rate and the ability of standard, Center for Disease Control (CDC)-designed surveillance techniques to detect these infections is unknown. The goal of this study was to determine whether recent changes in surgical care have led to an increased nosocomial infection rate based on number of discharges and whether current surveillance techniques are adequate to detect these complications. Data were collected prospectively on all nosocomial infections over a 1-year period on the general surgery, trauma, and transplant units at a university hospital, as independently observed by both the study team [surgical auditors (SA)] and CDC-trained infection control practitioners (ICP). The patient study group had a high acuity of illness (for 516 episodes of infection, mean APACHE II score of 15.4, 45% intensive care unit-bound, mortality of 16%). The overall infection rate per 100 discharges was 23.8 for SA and 12.2 for ICP (P < 0.001 by chi2), higher than historical reports. SA detected significantly more surgical site infections, pneumonias, and non-Clostridium difficile-related gastrointestinal infections. These relative rates of detection, however, were similar to those described previously in prior studies using similar methodologies. The nosocomial infection rate in surgical patients, based on number of discharges, appears to be increasing, perhaps due to increased inpatient acuity of illness. Current epidemiological methods provide estimates of infection rates with effectiveness similar to that reported in previous epidemiological studies but fail to recognize many infections otherwise identified by surgeons dedicated to infection control.

Centers for Disease Control and Prevention, U.S.↗