Biomedical subjects

William Henderson

Publications and source records attributed to William Henderson.

28 records · Page 2Linked to original sources

PubMed2002

Percutaneous coronary intervention versus coronary bypass graft surgery for diabetic patients with unstable angina and risk factors for adverse outcomes with bypass: outcome of diabetic patients in the AWESOME randomized trial and registry.

OBJECTIVES: This study compared survival after percutaneous coronary intervention (PCI) with survival after coronary artery bypass graft surgery (CABG) among diabetics in the Veterans Affairs AWESOME (Angina With Extremely Serious Operative Mortality Evaluation) study randomized trial and registry of high-risk patients. BACKGROUND: Previous studies indicate that CABG may be superior to PCI for diabetics, but no comparisons have been made for diabetics at high risk for surgery. METHODS: Over five years (1995 to 2000), 2,431 patients with medically refractory myocardial ischemia and at least one of five risk factors (prior CABG, myocardial infarction within seven days, left ventricular ejection fraction <0.35, age >70 years, or an intra-aortic balloon being required to stabilize) were identified. A total of 781 were acceptable for CABG and PCI, and 454 consented to be randomized. The 1,650 patients not acceptable for both CABG and PCI constitute the physician-directed registry, and the 327 who were acceptable but refused to be randomized constitute the patient-choice registry. Diabetes prevalence was 32% (144) among randomized patients, 27% (89) in the patient-choice registry, and 32% (525) in the physician-directed registry. The CABG and PCI survival rates were compared using Kaplan-Meier curves and log-rank tests. RESULTS: The respective CABG and PCI 36-month survival rates for diabetic patients were 72% and 81% for randomized patients, 85% and 89% for patient-choice registry patients, and 73% and 71% for the physician-directed registry patients. None of the differences was statistically significant. CONCLUSIONS: We conclude that PCI is a relatively safe alternative to CABG for diabetic patients with medically refractory unstable angina who are at high risk for CABG.

Aged↗

PubMed2002

Metal scrambling in the trinuclear (Pt(2)Se(2)M)(M = Pt, Pd, Au) system using an electrospray mass spectrometry (ESMS) directed synthetic methodology; isolation and crystallographic characterization of (Pt(2)(mu(3)-Se)(2)(PPh(3))(4)[Pt(cod)])(PF(6))(2) and (Pt(mu(3)-Se)(2)(PPh(3))(2)[Pt(cod)](2))(PF(6))(2) (cod = cyclo-octa-1,5-diene).

Pt(2)(mu-Se)(2)(PPh(3))(4) reacts with PtCl(2)(cod) to give (Pt(2)(mu(3)-Se)(2)(PPh(3))(4)[Pt(cod)])(2+) and an unexpected cod-rich product that arises from metal scrambling, viz. (Pt(mu(3)-Se)(2)(PPh(3))(2)[Pt(cod)](2))(2+). The formation of these species was detected and followed by electrospray mass spectrometry (ESMS) and subsequently verified by batch synthesis and crystallographic characterization. Other metal-scrambled aggregate products were successfully detected.

Journal Article↗

PubMed2002

Percutaneous coronary intervention versus coronary bypass graft surgery for patients with medically refractory myocardial ischemia and risk factors for adverse outcomes with bypass: The VA AWESOME multicenter registry: comparison with the randomized clinical trial.

OBJECTIVES: This study was designed to compare the three-year survival after percutaneous coronary intervention (PCI) or coronary artery bypass graft surgery (CABG) in physician-directed and patient-choice registries with the Angina With Extremely Serious Operative Mortality Evaluation (AWESOME) randomized trial results. BACKGROUND: The AWESOME multicenter randomized trial and registry compared the long-term survival after PCI and CABG for the treatment of patients with medically refractory myocardial ischemia and at least one additional risk factor for adverse outcome with CABG. The randomized trial demonstrated comparable three-year survival. METHODS: Over a five-year period (1995 to 2000), 2,431 patients with medically refractory myocardial ischemia and at least one of five risk factors (prior heart surgery, myocardial infarction within seven days, left ventricular ejection fraction <0.35, age >70 years, intra-aortic balloon required to stabilize) were identified. By physician consensus, 1,650 patients formed a physician-directed registry assigned to CABG (692), PCI (651) or further medical therapy (307), and 781 were angiographically eligible for random allocation; 454 of these patients constitute the randomized trial, and the remaining 327 constitute a patient choice registry. Survival for CABG and PCI was compared using Kaplan-Meier curves and log-rank tests. RESULTS: The CABG and PCI 36-month survival rates for randomized patients were 79% and 80%, respectively. The CABG and PCI 36-month survival rates were both 76% for the physician-directed subgroup; comparable survival rates for the patient-choice subgroup were 80% and 89%, respectively. None of the global log-rank tests for survival demonstrated significant differences. CONCLUSIONS: Both registries support the randomized trial conclusion: PCI is an alternative to CABG for some medically refractory high-risk patients.

Aged↗

PubMed2002

Morbidity and mortality of gastrectomy for cancer in Department of Veterans Affairs Medical Centers.

BACKGROUND: The purpose of this study was to define risk factors that predict 30-day morbidity and mortality after gastrectomy for cancer in Veterans Affairs (VA) Medical Centers. METHODS: The VA National Surgical Quality Improvement Program prospectively collected data on 708 patients undergoing gastrectomy for cancer in 123 participating VA medical centers from 1991 to 1998. Independent variables included 68 preoperative patient characteristics and 12 intraoperative variables; the dependent variables were 21 defined adverse outcomes and death. Predictive models for 30-day morbidity and mortality were constructed by using stepwise logistic regression analysis. RESULTS: The 30-day morbidity rate was 33.3% (236 of 708). The overall 30-day mortality rate was 7.6% (54 of 708). Significant positive predictors of morbidity (P <.05) included current pneumonia, American Society of Anesthesiologists class IV (threat to life), partially dependent functional status, dyspnea on minimal exertion, preoperative transfusion, extended operative time, and increasing age. Significant positive predictors of mortality (P <.05) included do not resuscitate status, prior stroke, intraoperative transfusion, preoperative weight loss, preoperative transfusion, and elevated preoperative alkaline phosphatase level. CONCLUSIONS: Risk factors predicting morbidity and mortality rates at VA hospitals after gastrectomy for gastric cancer are reported by using a prospectively collected, multi-institutional database. Assigning relative weights to factors associated with adverse outcomes may help improve patient care.

Adult↗

PubMed2002

Analysis of randomized controlled trials.

Although the sophistication and flexibility of the statistical technology available to the data analyst have increased, some durable, simple principles remain valid. Hypothesis-driven analyses, which were anticipated and specified in the protocol, must still be kept separate and privileged relative to the important, but risky data mining made possible by modern computers. Analyses that have a firm basis in the randomization are interpreted more easily than those that rely heavily on statistical models. Outcomes--such as quality of life, symptoms, and behaviors--that require the cooperation of subjects to be measured will come to be more and more important as trials move away from mortality as the main outcome. Inevitably, such trials will have to deal with more missing data, especially because of dropout and noncompliance. There are fundamental limits on the ability of statistical methods to compensate for such problems, so they must be considered when studies are designed. Finally, it must be emphasized that the availability of software is not a substitute for experience and statistical expertise.

Data Interpretation, Statistical↗

PubMed2002

Lower extremity nontraumatic amputation among veterans with peripheral arterial disease: is race an independent factor?

OBJECTIVES: To determine if race/ethnicity is independently associated with an increased risk for nontraumatic lower extremity amputation versus lower extremity bypass revascularization among patients with peripheral arterial disease (PAD). METHODS: Data were analyzed from the National VA Surgical Quality Improvement Program (NSQIP) and from the Veterans Affairs Patient Treatment File (PTF). Race/ethnicity was defined as non-Hispanic white, black, or Hispanic. Variables that were univariately associated (P < or = 0.05) with the outcome of amputation were placed into a multiple logistic regression model to determine independent predictors for the dependent variable, lower extremity amputation versus lower extremity bypass revascularization. RESULTS: Three thousand eighty-five lower extremity amputations and 8409 lower extremity bypass operations were identified. Among all cases included, there were 416 Hispanic patients (3.6%), 2337 black patients (20.3%), and 8741 non-Hispanic white patients (76.1%). Among all variables within the model, Hispanic and black race were each associated with a greater risk for amputation than a history of rest pain/gangrene (Hispanic race 1.4, 95% CI 1.1, 1.9; black race 1.5, 95% CI 1.4, 1.7; rest pain/gangrene 1.1, 95% CI 1.0, 1.3). The final model had a c statistic of 0.83. CONCLUSION: Hispanic race and black race were independent risk factors for lower extremity amputation in patients with PAD. Although the burden of certain atherosclerotic risk factors (eg, diabetes and hypertension) is higher in minority patients, the impact of this burden does not account for the increased risk for the outcome of lower extremity amputation in these two populations. Further research is needed to better understand the reason(s) why race/ethnicity is independently associated with poor outcomes in PAD.

Activities of Daily Living↗

PubMed2002

To what extent should quality of care decisions be based on health outcomes data? Application to carotid endarterectomy.

BACKGROUND AND PURPOSE: Most quality improvement methods implicitly assume that facilities with high complication rates are likely to have substandard processes of care, a stable characteristic that, in the absence of intervention, will persist over time. We assessed the extent to which this holds true for carotid endarterectomy. METHODS: Using data from the Department of Veterans Affairs National Surgical Quality Improvement Project, we classified facilities on the basis of 30-day complications of carotid endarterectomy (stroke, myocardial infarction, death) during 1994 to 1995 (period 1, n=3389) and then compared these groups of facilities for complication rates during 1996 to 1997 (period 2, n=4453). RESULTS: Despite wide variation in facility-specific complication rates, the correlation between rates in periods 1 and 2 was low (Spearman correlation coefficient, 0.04; P=0.01) Facility-specific rates did not show greater correlation when we examined only facilities with higher volumes patients in different clinical categories (asymptomatic, transient ischemic attack, stroke). Comorbid illness profiles were similar between the 2 time periods. CONCLUSIONS: Most of the facility-specific differences in complication rates in period 1 were not maintained into period 2. Many apparent quality improvement problems may not be as large as they first appear, especially when based on few complications per facility. The inability, in practice, to estimate complication rates at a high degree of precision is a fundamental difficulty for clinical policy making regarding procedures with complication rates such as carotid endarterectomy.

Aged↗

PubMed1997

Electrospray Mass Spectrometry of Thiophenolate-Capped Clusters of CdS, CdSe, and ZnS and of Cadmium and Zinc Thiophenolate Complexes: Observation of Fragmentation and Metal, Chalcogenide, and Ligand Exchange Processes.

Electrospray mass spectrometry provides a rapid, convenient technique for characterizing and studying the chemistry of anionic metal sulfide thiolate clusters. Negative-ion electrospray mass spectra have been recorded for the thiophenolate-capped clusters [Me(4)N](4)[E(4)Cd(10)(SPh)(16)] (E = S, Se), [Me(4)N](4)[S(4)Zn(10)(SPh)(16)], and [Me(4)N](2)[S(4)Cd(17)(SPh)(28)] and of the metal thiophenolate complexes [Me(4)N](2)[M(SPh)(4)], [Me(4)N](2)[M(4)(SPh)(10)] (M = Cd, Zn), and [Et(4)N](2)[Cd(4)X(4)(SPh)(6)] (X= Cl, Br, I). The exchanges of M, E, and X which occur in various mixtures of these clusters and complexes and the fragmentation processes have been investigated. In the clusters the M-E bonds involving the sulfide or selenide core remain intact during the observed fragmentation at low cone voltages. At high cone voltages, monoions are ultimately formed by loss of charged species and neutral M(SPh)(2), resulting in almost complete removal of the SPh(-) ligands from the cluster core. Fragmentation of the ME core unit itself occurs only at very high voltages. The exchange of X in [Et(4)N](2)[Cd(4)X(4)(SPh)(6)] (X = Br, I) gives peaks due to the ions [Cd(4)I(n)()Br(m)()(SPh)(10)(-)(()(n)()(+)(m)()())](2)(-) (n + m = 0-4) and fragment ions with mixed ligands. The nature of the detected species suggests that the halides only exist as terminal ligands. The exchange of M in [Me(4)N](2)[M(4)(SPh)(10)] and [Me(4)N](4)[S(4)M(10)(SPh)(16)] results in the mixed-metal complexes [Cd(4)(-)(n)()Zn(n)()(SPh)(10)](2)(-) (n = 0-4) and the mixed-metal clusters [S(4)Cd(10)(-)(n)()Zn(n)()(SPh)(16)](4)(-) (n = 0-10). The exchange follows random statistics in [M(4)(SPh)(10)](2)(-) but is biased toward equilibrium association of the same metal in [S(4)M(10)(SPh)(16)](4)(-). The rates of exchange within the different structural elements of [S(4)M(10)(SPh)(16)](4)(-) and [S(4)M(17)(SPh)(28)](2)(-) decrease for the atoms located toward the center of the clusters.

Journal Article↗

PubMedDate not supplied

Design of the cooperative study on glycemic control and complications in diabetes mellitus type 2: Veterans Affairs Diabetes Trial.

INTRODUCTION: Long-term glycemic control trials in type 2 diabetes show as the main clinical benefit a difference in retinal photocoagulation (3/1000 in the UK Prospective Diabetes Study [UKPDS]), but no effect on visual acuity or renal failure. No intensive glycemic control trial has yet affected cardiovascular (CV) events, the main cause of morbidity and mortality. By contrast, modest blood pressure reduction has protective effects on visual acuity, renal function, CV events, and mortality. Optimal glycemic control goals are not established in elderly, obese persons with advanced complications, the most common patients in the Veterans Affairs (VA) system. The earlier feasibility trial in such patients (VA-CSDM) suggested potentially worse CV outcomes with lower attained hemoglobin A1c (HbA1c) levels. OBJECTIVES: The primary objective of the Veterans Affairs Diabetes Trial (VADT) is the assessment of the effect of intensive glycemic treatment on CV events. Other objectives are effects on microangiopathy, quality of life, and cost effectiveness. RESEARCH DESIGN AND METHODS: The VADT, started in December 2000, is enrolling 1700 men and women previously uncontrolled on insulin or maximum doses of oral agents at 20 VA medical centers. Accrual is 2 years and follow-up is 5-7 years, with visits every 1.5 months. The study has a power of 86% to detect a 21% relative reduction in major CV events (CV death, myocardial infarction [MI], cerebrovascular accident [CVA], congestive heart failure [CHF], revascularization and amputation for ischemia). Subjects are randomized to an intensive arm aiming at normal HbA1c levels or to a standard arm with usual, improved glycemic control. An HbA1c separation of >1.5% is to be maintained (expected 2%). Both arms receive step therapy: glimepiride or metformin plus rosiglitazone and addition of insulin or other oral agents to achieve goals. Strict control of blood pressure and dyslipidemia, daily aspirin, diet, and education are identical in both arms. Plasma fibrinogen, plasminogen-activating inhibitor I (PAI-I), lipids, renal function parameters, and ECG are measured throughout. Stereo retinal photographs are obtained at entry and 5 years, eye examinations yearly, and intervention as needed to prevent visual deterioration. Recruitment is proceeding on schedule: the current mean HbA1c at entry is 9.4+/-1.6% and mean duration of diagnosed diabetes 11+/-8 years.

Adult↗

PubMedDate not supplied

Pediatric Sweet syndrome and immunodeficiency successfully treated with intravenous immunoglobulin.

Painful erythematous plaques and a pathognomonic, dense, dermal infiltrate of neutrophils characterize Sweet syndrome. Although numerous instances of this disease have been reported in children, only four have had an associated immunodeficiency to date. Sweet syndrome has been traditionally treated with systemic corticosteroids despite an unknown pathogenesis. Prior reports suggest that immunodeficient children with Sweet syndrome may have a persistent course and fail to respond to standard treatment. We describe a child with debilitating Sweet syndrome and a primary immunodeficiency whose symptoms were controlled with intravenous immunoglobulin and dapsone.

Child, Preschool↗