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Biomedical subjects

J G Wright

Publications and source records attributed to J G Wright.

At least 19 recordsLinked to original sources
PubMed1998

Independent prognostic significance of ischemic ST-segment response limited to recovery from treadmill exercise in asymptomatic subjects.

BACKGROUND: Although exercise-induced ST depression is an independent predictor of future coronary events in asymptomatic populations, the predictive value of ST depression beginning after exercise cessation is unknown. METHODS AND RESULTS: We analyzed the treadmill exercise tests of 825 healthy volunteers who were 22 to 89 years of age from the Baltimore Longitudinal Study of Aging. All subjects were free from coronary heart disease by history, physical examination, and resting ECG. From 825 participants, 611 (group 0) had no ischemic ST-segment changes during or after treadmill exercise, while 214 subjects developed > or = 1-mm flat or downsloping ST depression: 151 (group 1) had ST changes starting during exercise, and 63 (group 2) had changes limited to recovery. Groups 1 and 2 were similar in age, sex, smoking status, hypertension prevalence, fasting plasma glucose, and serum cholesterol (CHOL). However, both groups were older and had higher CHOL and prevalence of hypertension than group 0. Treadmill exercise duration, peak oxygen consumption, and maximal heart rate were similar between groups 1 and 2 but were lower than in group 0 (each P < 0.05). During a mean follow-up time of 9 years, 55 subjects developed coronary events (angina pectoris, myocardial infarction, or coronary death): 21 of 611 (3.4%) in group 0, 22 of 151 (14.6%) in group 1, and 12 of 63 (19%) in group 2 (P = 0.001). By survival analysis, the risk of coronary events was similar in groups 1 and 2 but significantly higher than in group 0 (P < 0.0001). Multiple logistic regression showed that age (odds ratio [OR] = 1.07 per year, P = 0.00001), CHOL (OR = 1.02 per 1 mg, P = 0.0001), and presence of ST-segment depression (OR = 2.59, P = 0.007 and OR = 2.38, P = 0.04 for groups 1 and 2, respectively) were independent predictors of events. CONCLUSIONS: Thus, ischemic ST-segment changes developing during recovery from treadmill exercise in apparently healthy individuals have adverse prognostic significance similar to those appearing during exercise.

Adult↗
PubMed1998

Patient characteristics that affect the outcome of total hip arthroplasty: a review.

OBJECTIVE: To review the literature regarding patient factors pertinent to the outcome of total hip arthroplasty (THA). DATA SOURCE: MEDLINE from 1966 onward (key words "hip prosthesis" and "treatment outcome") and literature previously known to the authors and cited in papers from all sources. STUDY SELECTION: All identified studies were included provided the methodology permitted assessment of the effect of patient factors and a clear outcome was defined (either prosthesis survival or specific functional outcomes). DATA EXTRACTION: The patient factors, methods and outcomes described in each paper were summarized on a data extraction form. DATA SYNTHESIS: All data were reviewed by one author. This process was repeated by a second author, and the findings were reviewed by the remaining 2 authors to verify the findings. The best functional outcomes and prosthesis survival rates were reported among patients who were between 45 and 75 years of age, weighed less than 70 kg, had strong social support, had a higher educational level, had better preoperative functional status and had no comorbid disease. CONCLUSION: Important research remains to be done to examine the magnitude and interaction of patient factors on the the outcome of THA.

Age Factors↗
PubMed1997

Use of the splenic and hepatic artery for renal revascularization in patients with atherosclerotic renal artery disease.

Hepatorenal and splenorenal bypasses are gaining an increased popularity as an alternative to renal artery endarterectomy and aortorenal bypass in selected patients. However, there are few reports of the long-term results of this procedure. The purpose of this study was to assess the performance of the hepatic and splenic arterial sources in patients with atherosclerotic renal artery disease. We reviewed our 7-year experience between 1988-1995. A total of 146 operative renal artery reconstructions were performed, including 45 hepatorenal and/or splenorenal bypass in 38 patients, (19 male, 19 female, mean age 62 +/- 12 years) for treatment of renovascular hypertension, renal preservation or both. The mean preoperative creatinine was 2.95 mg/dl (2.11-3.47, 95% confidence limits). The average number of antihypertensive medications was 2.63. There was one postoperative death from myocardial infarction and two cases of early graft thrombosis, one of which was treated by thrombectomy reestablishing patency. In two patients with persistent hypertension selective angiography demonstrated high-grade anastomotic stenoses which were successfully dilated by balloon angioplasty. The postoperative mean creatinine decreased to 2.54 mg/dl (1.82-3.27, 95% confidence limits), (p = 0.17) and the average number of antihypertensive medications decreased to 1.9 (p = 0.001). During the median follow-up of 33 months, 10 patients died, mainly from cardiac causes. Our experience indicates that the splenic and hepatic arteries provide useful alternatives to renal revascularization in selected circumstances with an acceptable rate of perioperative mortality and morbidity. The expected long-term survival in this group of patients is low.

Anastomosis, Surgical↗
PubMed1997

A prospective randomized trial of preoperative "optimization" of cardiac function in patients undergoing elective peripheral vascular surgery.

BACKGROUND: Previous investigations have suggested that preoperative invasive hemodynamic monitoring with "optimization" of cardiovascular function may favorably affect the outcome among patients undergoing peripheral vascular surgery. The purpose of this study was to evaluate the effect of preoperative optimization of hemodynamic parameters on outcome in patients undergoing aortic reconstruction (AR) or limb salvage procedures (LSP) in a randomized, prospective clinical trial. METHODS: All 72 patients who consented to participate in this study were admitted to the intensive care unit at least 12 hours before operation for placement of a pulmonary artery catheter (PAC). Patients who were randomized to the treatment group (n = 32) were "optimized" by adjusting their hemoglobin concentration, oxygen saturation (SaO2), cardiac output, or afterload until the mixed venous O2 saturation (SvO2) was at least 65%. The control group (n = 40) underwent placement of a PAC and had oxygen transport parameters measured without any attempt to optimize SvO2. RESULTS: There were no significant differences between the treatment and control groups with respect to age, gender, type of operation, initial Acute Physiology and Chronic Health Evaluation (APACHE) II score, SvO2, pulmonary artery occlusion pressure, or cardiac index. All treatment patients achieved an SvO2 of at least 65% before operation. Comparing the treatment and control groups, postoperative cardiovascular complications occurred in 25% versus 27%, intraoperative complications in 28% versus 20%, and death in 9% versus 5%, respectively. None of these differences was statistically significant as a whole or within the subgroups undergoing AR or LSP. CONCLUSIONS: These data suggest that preoperative optimization of cardiovascular function by using achievement of SvO2 above 65% as the end point does not result in any reduction of intraoperative or perioperative cardiac complications in patients undergoing PVS. Further studies with alternative assessments and manipulation of different cardiopulmonary parameters may yield additional information.

Aged↗
PubMed1997

Outcome studies in surgical research.

Providers, payers, buyers, and the public at large will continue to demand information regarding the quality of health care service. High quality clinical and functional data on the entire population would not only allow a better understanding of health outcomes after medical or surgical interventions but would also provide information regarding disease burden, the population at risk, and indications for treatment. We currently are dealing with two separate pieces of the puzzle. On the one hand, randomized clinical trials and observational studies continue to provide high quality information regarding small samples of the population. On the other hand, the analysis of large administrative data sets provides a broad overview of health care services and patient outcomes at the population level. To provide meaningful data regarding the quality of health care, we must go beyond morbidity and mortality rates and attempt to measure patient function at the population level.

Clinical Trials as Topic↗
PubMed1997

Accuracy of administrative data for assessing outcomes after knee replacement surgery.

OBJECTIVE: To assess the accuracy of information in an administrative database (Canadian Institute for Health Information; CIHI) compared with the hospital record for patients undergoing knee replacement (KR). METHODS: A stratified random sample of 185 KR recipients from 5 Ontario hospitals were chosen. Their hospital records and corresponding CIHI files were compared to assess percent complete agreement, false negative (FN) and false positive (FP) rates for demographic data, procedures, and diagnoses. RESULTS: Of 185 records, 175 (95%) were reviewed. Percent complete agreement was greater than 94% for each of patient demographics and procedures (mean FN rates: 0%; mean FP rates: 0-5%). For comorbidities and complications, although mean percent complete agreement was high, and FP rates were low, mean FN rates were 63% for specific comorbid conditions and 70% for organ systems. CONCLUSIONS: High FN rates have been found in documentation of comorbidities and in-hospital complications for CIHI data compared with the hospital record. Under-coding of comorbidities and in-hospital complications has potential implications for researchers using administrative databases.

Comorbidity↗
PubMed1997

A comparison of different indices of responsiveness.

The first purpose of this study was to determine if different indices of responsiveness provided similar rank orderings of scales in terms of responsiveness. The second purpose was to compare the responsiveness of patient-specific, disease-specific, and generic health status measures for patients undergoing total hip arthroplasty. All patients of one surgeon at a single institution were eligible for the study. Patients who did not speak English or did not return for post-operative evaluations were excluded. Patients completed two disease-specific scales (the Harris Hip Scale and the Western Ontario and McMaster osteoarthritis scale or WOMAC), one generic health status scale (the SF-36), and two patient-specific scales (the McMaster-Toronto Arthritis questionnaire or MACTAR and the Patient Specific Index or PASI). All scales were administered on two occasions: before and 6 months after total hip arthroplasty. Responsiveness was measured using: (1) the responsiveness statistic; (2) standardized response mean; (3) relative efficiency statistic; (4) effect size; and also by (5) correlating each scale's change score with the change in patients' global ratings of their "hip function." Seventy-eight sequential patients completed the study. The mean age was 62 years (range 25-87), 55% were male, and 71% had osteoarthritis. Test-retest reliability of the scales ranged from 0.31 to 0.93. The correlation among scales was consistent with a priori hypotheses confirming construct validity of the scales. Although the disease-specific scales were generally rated as the most responsive scales, the different indices provided different rank orderings by up to 5 levels (p = 0.04). In conclusion, disease-specific scales are the most responsive scales. However, choosing among scales based on responsiveness must be done with caution because different indices of responsiveness provide different rank ordering.

Adult↗
PubMed1997

Factors influencing the long-term results of abdominal aortic aneurysm repair.

The incidence of late graft complications such as para-anastomotic aneurysms, aortoenteric fistulas and graft infections following abdominal aortic aneurysm (AAA) repair is a major determinant of its overall benefit, yet most published reports of AAA repair have concentrated almost exclusively on the early postoperative mortality and morbidity. Accurate knowledge regarding the incidence of late complications is essential to making any decision regarding the operative vs nonoperative management of AAAs. A similar analysis must be applied to endovascular repair of AAAs before this technique is accepted as an alternative method of treating AAAs. In this article we review the current knowledge and understanding on the late results following aortic aneurysm repair.

Anastomosis, Surgical↗
PubMed1997

Protein C and protein S in homozygous sickle cell disease: does hepatic dysfunction contribute to low levels?

The aim of this study was to confirm reports of low protein C (PC) and S (PS) concentrations in steady-state patients with homozygous sickle cell (SS) disease when compared to a racially matched normal haemoglobin (AA) control group and to examine the mechanisms of this reduction with respect to hepatic function, coagulation activation and haematological indices. In 36 SS patients and 35 AA race-matched controls PC (functional and immunoreactive), PS (free and total) were measured. C4B binding protein (C4B) was assessed by immunoelectrophoresis and D-dimer by ELISA. Hepatic function was assessed by prothrombin (PT) time (49 SS, 64 AA), factor V (34 SS, 36 AA) and factor VII concentrations (28 SS, 29 AA). Proteins induced in vitamin K absence or antagonism (PIVKA) were sought in 12 SS's. The relationship between PC, PS and total bilirubin, haemoglobin (Hb) F and reticulocyte count was also assessed. PC, PS and C4B were lower in SS disease. SS patients had longer PT times, and lower factor V and VII concentrations in comparison to AA controls. PC (functional and immuno-reactive) and free PS correlated with PT. Within SS genotype PT correlated negatively with factor V and factor VII. Factor V and VII were positively correlated. PIVKAs were not detected. There was no correlation between PC, PS and D-dimer, haemolytic rate or Hb F concentration. Prolongation of PT time, low factor V and VII suggest that hepatic dysfunction, rather than coagulation activation or haemolytic rate, accounts for the reduced concentrations of PC and PS in steady-state SS disease. The absence of PIVKAs suggests a hepatocellular problem.

Anemia, Sickle Cell↗
PubMed1997

Activated protein C resistance in homozygous sickle cell disease.

The activated protein C resistance (APC-R) ratios in 50 patients with steady state homozygous sickle cell (SS) disease and 59 healthy AA controls was measured. There was a significant reduction in median APC-R ratio in sickle cell disease compared to controls. This reduction in APC-R ratio was not explained by (1) the presence of the factor V Leiden, found in only one of 165 patients with SS disease including those tested for APC-R, or (2) the presence of lupus anticoagulants. However, the raised levels of factor VIIIC in SS patients in this study may be contributing to increased resistance to APC, which in turn may contribute to the vaso-occlusive complications of SS disease.

Adolescent↗
PubMed1997

Economic evaluation of 2 treatments for pediatric femoral shaft fractures.

The purpose of this study was to assess the relative health system costs of early hip spica cast immobilization and external fixation for pediatric femoral shaft fractures. A cost analysis was performed from the viewpoint of the study hospital and physicians using protocols based on current practice. Cost estimates were based on patient and financial information from April 1, 1993, to January 31, 1994, including the fully allocated inpatient and outpatient costs. A sensitivity analysis was conducted to analyze the effect of complications on costs. Total estimated costs (in 1994 Canadian dollars, $1.00 = $0.75 US) of uncomplicated external fixation and hip spica treatments were $7626.30 and $5970.11, respectively. Fifty percent of this difference was attributable to longer inpatient stays for the external fixation treatment. The remaining difference was because of the cost of the fixator, additional operating room staff time costs, and additional professional and technical fees. Total expected costs of treatment complicated by loss of reduction, pin tract infection, and return to the operating room were $7716.01 and $6128.44 for the external fixation and hip spica treatment options, respectively. For the range of complication probabilities considered, expected total costs were always greater with the external fixation option than with the hip spica treatment.

Canada↗
PubMed1997

Convergent dislocation of the elbow.

Proximal radioulnar translocation is an extremely rare injury. Only seven cases have been reported previously. The authors report the case of a 6-year-old girl whose translocation was undiagnosed for more than 2 weeks. Definitive treatment required open reduction and use of a radiocapitellar pin to stabilize the proximal radius. At the 2-year followup, the patient has no symptoms and has resumed full activity with nearly full range of motion. To ensure early diagnosis of rare types of elbow dislocations, it is important to recognize the lack of supination and disruption of the radiocapitellar relationship on radiographs.

Bone Nails↗
PubMed1997

The patient-specific index: asking patients what they want.

The Patient-Specific Index is used to assess the outcome of total hip arthroplasty by evaluating the preferences of the individual patient. The purpose of this study was to determine the reliability, validity, and responsiveness of this index and to compare different methods of combining patients' ratings of the severity and importance of their complaints, to obtain Patient-Specific Index summary scores. All patients who were scheduled to have a total hip arthroplasty performed by one surgeon at a single institution were eligible for the study. The patients completed the Harris hip score form, the McMaster-Toronto Arthritis (MACTAR) Patient Preference Disability Questionnaire, the Short Form-36, the Western Ontario and McMaster University Osteoarthritis Index (WOMAC), and the Patient-Specific Index. With use of the Patient-Specific Index, patients rated the severity and importance of each complaint. These ratings were summed in four different ways to derive severity-importance scores. The questionnaires were completed twice (two weeks apart) before the total hip arthroplasty and twice (two weeks apart) six months after the total hip arthroplasty by a subset of the patients. The seventy-eight participating patients had a mean age of 62.2 years (range, twenty-five to eighty-seven years) at the time of the operation. Forty-three patients (55 per cent) were men, and sixty-three (81 per cent) had osteoarthrosis. The inter-rater and intra-rater test-retest random-effects intraclass correlation coefficients of the Patient-Specific Index were 0.77 or greater (greater than 0.75 is considered excellent). Construct validity was shown by correlations of the Patient-Specific Index with other scales. The additive versions of the Patient-Specific Index (with a responsiveness statistic of 3.3 or greater and a standardized response mean of 1.6 or greater) were more responsive than the other scales. We concluded that the Patient-Specific Index is reliable, valid, and responsive. The additive versions were the most responsive and are recommended for future applications. Such indices need to be tested in studies of patients who have osteoarthrosis of the hip and other musculoskeletal diseases, to ensure generalizability of the results.

Activities of Daily Living↗
PubMed1997

The relationship between variations in knee replacement utilization rates and the reported prevalence of arthritis in Ontario, Canada.

OBJECTIVE: To determine the relationship between regional variations in knee replacement (KR) utilization rates in Ontario, Canada, and the reported prevalence of arthritis and rheumatism as a chronic health problem. METHODS: Utilization data were acquired from the Canadian Institute for Health Information for KR procedures performed in Ontario between fiscal years 1984 and 1990. Census information was obtained from Statistics Canada. Disease prevalence data were derived from the 1990 Ontario Health Survey (OHS). Public Health Units (PHU) were used as the unit of analysis, with utilization rates defined as the number of KR performed on all PHU residents (irrespective of where these procedures were performed) divided by the population. Direct methods were used to standardize utilization for age, sex, and disease prevalence. The extremal quotient, the weighted coefficient of variation, and the systematic component of variation were used as measures of variation. The relationship between the number of KR performed in each age-sex-year strata and various demographic (age and sex), disease prevalence, and regional dummy variables was estimated using a Poisson regression model. RESULTS: Regional variation in the standardized utilization of KR surgery was wide, but declined over the study period; the extremal quotient fell from 8.0 to 3.3, the weighted coefficient of variation fell from 0.49 to 0.30, and the systematic component of variation fell from 0.20 to 0.17. Variation in the provision of KR surgery remained even after controlling for the demographic composition of the population and disease prevalence. Moreover, while demographic, regional, and temporal covariates were significant (p < 0.0001) in accounting for over 90% of the variation in utilization, disease prevalence was not significant (p > 0.05). CONCLUSION: This study merged population based reports of disease prevalence with administrative data to account for regional variations in utilization. While regional variations in KR surgery have fallen over time, variations remain even after adjusting for patient reported disease prevalence. The finding that demographic variables and the reported prevalence of disease were poorly correlated suggests that current area variation studies may not be adjusting fully for disease prevalence or severity.

Aged↗
PubMed1996

A comparison of radiographic and electrogoniometric angles in adolescent idiopathic scoliosis.

STUDY DESIGN: This was a cross-sectional study of a consecutive group of adolescent patients presenting to a scoliosis clinic for routine assessment or monitoring of their scoliosis, excluding postsurgical patients. SUMMARY OF BACKGROUND DATA: In vitro studies suggested electrogoniometry could be useful in the evaluation of scoliosis. No prior in vitro study had been performed. OBJECTIVES: To determine the reliability and validity of an electrogoniometric instrument, the Metrecom Skeletal Analysis System, in assessing adolescent idiopathic scoliosis. METHODS: Thirty-one patients were examined, radiographed, and scanned with the Metrecom Skeletal Analysis System twice by two different examiners. The magnitudes of the curves derived from the Metrecom Skeletal Analysis System scans were compared with each other and with the Cobb angles measured from standing radiographs. RESULTS: The intraclass correlation coefficient (a measure of agreement, ranging from 0 to 1, where 1 represents complete agreement) for the intraexaminer reliability of the Metrecom Skeletal Analysis System ranged from 0.71 to 0.83. The interexaminer reliability intraclass correlation coefficient of the Metrecom Skeletal Analysis System was 0.58, with a mean difference between examiners of 5.5 degrees (SD = 5 degrees), and limits of agreement (mean difference +/-2 SD) ranging from -4.5 degrees to 15.6 degrees. The Metrecom Skeletal Analysis System and the radiographically derived Cobb angle correlation was 0.64, but the mean difference between the methods was 3.7 degrees (SD = 11.1), with limits of agreement from 18.4 degrees to 25.9 degrees. CONCLUSION: The Metrecom Skeletal Analysis System does not provide sufficient clinical precision to substitute for the Cobb angle measured from spinal radiographic measurements in the management of adolescents with scoliosis.

Adolescent↗
PubMed1996

Variability in physicians' reported ordering and perceived reassurance value of diagnostic tests in children with 'growing pains'.

OBJECTIVES: To determine the variability in the reported ordering of tests and treatment and to determine physicians' perceptions of the reassurance value to families of diagnostic tests in children with "growing pains." DESIGN: Cross-sectional survey using a mailed questionnaire. SETTINGS: Primary care and referral practices in Toronto, Ontario. PARTICIPANTS: University-affiliated primary care pediatricians and family physicians were surveyed, as well as all pediatric orthopedic surgeons and pediatric rheumatologists in Ontario. Pediatric orthopedic surgeons and pediatric rheumatologists were combined into a single group. MAIN OUTCOME MEASURES: Frequency of office visits because of growing pains, frequency of diagnostic testing, management strategies for these children, and physicians' perceptions of the reassurance value of diagnostic tests. RESULTS: Of 205 eligible physicians, 181 (88.3%) responded. The median reported frequency of office visits because of growing pains was 1%. Compared with the other physician groups, family physicians were significantly more likely to order a determination of the hemoglobin level (P = .003), erythrocyte sedimentation rate (P = .01), white blood cell count (P = .01), and differential blood cell count (P = .003), but not imaging tests. Family physicians were also more likely to order diagnostic tests when they were under parental pressure to do so (P = .001) or for the child with repeated visits (P = .02). In total, 86% of pediatric orthopedic surgeons and pediatric rheumatologists, 95% of pediatricians, and 100% of family physicians perceived normal test results to be reassuring to parents. Treatment strategies were similar across the 3 physician groups. CONCLUSIONS: The frequency of diagnostic testing varied among physician groups. Virtually all physicians perceived normal test results to be reassuring to families.

Adult↗