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Biomedical subjects

R H Jones

Publications and source records attributed to R H Jones.

At least 37 records · Page 2Linked to original sources
PubMed2001

Prospective randomized trial of normothermic versus hypothermic cardiopulmonary bypass on cognitive function after coronary artery bypass graft surgery.

BACKGROUND: Despite significant advances in cardiopulmonary bypass (CPB) technology, surgical techniques, and anesthetic management, central nervous system complications occur in a large percentage of patients undergoing surgery requiring CPB. Many centers are switching to normothermic CPB because of shorter CPB and operating room times and improved myocardial protection. The authors hypothesized that, compared with normothermia, hypothermic CPB would result in superior neurologic and neurocognitive function after coronary artery bypass graft surgery. METHODS: Three hundred patients undergoing elective coronary artery bypass graft surgery were prospectively enrolled and randomly assigned to either normothermic (35.5-36.5 degrees C) or hypothermic (28-30 degrees C) CPB. A battery of neurocognitive tests was performed preoperatively and at 6 weeks after surgery. Four distinct cognitive domains were identified and standardized using factor analysis and were then compared on a continuous scale. RESULTS: Two hundred twenty-seven patients participated in 6-week follow-up testing. There were no differences in neurologic or neurocognitive outcomes between normothermic and hypothermic groups in multivariable models, adjusting for covariable effects of baseline cognitive function, age, and years of education, as well as interaction of these with temperature treatment. CONCLUSIONS: Hypothermic CPB does not provide additional central nervous system protection in adult cardiac surgical patients who were maintained at either 30 or 35 degrees C during CPB.

Anesthetics, Intravenous↗
PubMed2000

Comparison of medicine alone, coronary angioplasty, and left internal mammary artery-coronary artery bypass for one-vessel proximal left anterior descending coronary artery disease.

Despite the deleterious and sometimes catastrophic consequences of proximal left anterior descending (LAD) artery occlusion, there is a paucity of data to guide the treatment of patients with such disease. Our aim was to describe outcomes with medical therapy, angioplasty, or left internal mammary artery (LIMA) bypass grafting in patients with 1-vessel, proximal LAD disease. We retrospectively analyzed prospectively collected data from 1,188 patients first presenting only with proximal LAD disease at 1 center over 9 years. We assessed the rates of death, acute myocardial infarction, and repeat intervention by initial treatment over a median 5.7 years of follow-up. Patients undergoing angioplasty or LIMA bypass were more often men and had progressive or unstable angina; those receiving medical therapy had a lower median ejection fraction. Both revascularization procedures offered slightly better adjusted survival versus medicine (hazard ratio for angioplasty, 0.82; 95% confidence interval, 0.60 to 1.11; hazard ratio for bypass, 0.74; 95% confidence interval, 0.44 to 1.23). Bypass, but not angioplasty, was associated with significantly fewer composite end point events (death, infarction, or reintervention, p <0.0001), and angioplasty was associated with a higher composite event rate than bypass or medical therapy (p <0.0001 and p = 0.0003, respectively). The initial advantages of bypass and medicine over angioplasty diminished over time; angioplasty became more advantageous than medicine after 1 year (p = 0.05) and not significantly different from bypass. Treatment of 1-vessel, proximal LAD disease with medicine, angioplasty, or UMA bypass resulted in comparable adjusted survival. However, LIMA bypass alone reduced the long-term incidence of infarctions and repeat procedures.

Aged↗
PubMed2000

Predictors of mortality and mortality from cardiac causes in the bypass angioplasty revascularization investigation (BARI) randomized trial and registry. For the BARI Investigators.

BACKGROUND: The impact of percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass grafting (CABG) on long-term mortality rates in the presence of various demographic, clinical, and angiographic factors is uncertain in the population of patients suitable for both procedures. METHODS AND RESULTS: In the Bypass Angioplasty Revascularization Investigation (BARI) randomized trial and registry, 3610 patients who were eligible to receive PTCA and CABG were revascularized between 1989 and 1992. Multivariate Cox models were used to identify factors associated with 5-year mortality and cardiac mortality, with particular attention to factors that interact with treatment. Diabetic patients receiving insulin had higher mortality and cardiac mortality rates with PTCA compared with CABG (relative risk [RR] 1.78 and 2.63, respectively, P<0.001), and patients with ST elevation had higher cardiac mortality rates with CABG than with PTCA (RR 4.08, P<0.001). Factors most strongly associated with high overall mortality rates were insulin-treated diabetes, congestive heart failure, kidney failure, and older age. Black race was also associated with higher mortality rates (RR 1.49, P=0.019). CONCLUSIONS: A set of variables was identified that could be used to help select a revascularization procedure and to evaluate risk of long-term mortality in the population of patients considering revascularization.

Angioplasty, Balloon, Coronary↗
PubMed2000

Outcomes of cardiac surgery in patients > or = 80 years: results from the National Cardiovascular Network.

OBJECTIVES: The purpose of this study was to evaluate characteristics and outcomes of patients age > or =80 undergoing cardiac surgery. BACKGROUND: Prior single-institution series have found high mortality rates in octogenarians after cardiac surgery. However, the major preoperative risk factors in this age group have not been identified. In addition, the additive risks in the elderly of valve replacement surgery at the time of bypass are unknown. METHODS: We report in-hospital morbidity and mortality in 67,764 patients (4,743 octogenarians) undergoing cardiac surgery at 22 centers in the National Cardiovascular Network. We examine the predictors of in-hospital mortality in octogenarians compared with those predictors in younger patients. RESULTS: Octogenarians undergoing cardiac surgery had fewer comorbid illnesses but higher disease severity and surgical urgency than younger patients. Octogenarians had significantly higher in-hospital mortality after cardiac surgery than younger patients: coronary artery bypass grafting (CABG) only (8.1% vs. 3.0%), CABG/aortic valve (10.1% vs. 7.9%), CABG/mitral valve (19.6% vs. 12.2%). In addition, they had twice the incidence of postoperative stroke and renal failure. The preoperative clinical factors predicting CABG mortality in the very elderly were quite similar to those for younger patients with age, emergency surgery and prior CABG being the powerful predictors of outcome in both age categories. Of note, elderly patients without significant comorbidity had in-hospital mortality rates of 4.2% after CABG, 7% after CABG with aortic valve replacement (CABG/AVR), and 18.2% after CABG with mitral valve replacement (CABG/MVR). CONCLUSIONS: Risks for octogenarians undergoing cardiac surgery are less than previously reported, especially for CABG only or CABG/AVR. In selected octogenarians without significant comorbidity, mortality approaches that seen in younger patients.

Aged↗
PubMed2000

Predictors of mortality for patients undergoing cardiac valve replacements in New York State.

BACKGROUND: The objective of this study was to identify the mortality rates and significant independent risk factors for mortality for each of six valve replacement groups. METHODS: A total of 14,190 patients who underwent valve replacement in New York State from 1995 to 1997 were classified into six major groups and significant independent risk factors for inpatient mortality were identified for each of the groups using stepwise logistic regression. RESULTS: Mortality rates ranged from 3.33% for isolated aortic valve surgical procedures to 18.72% for multiple valve replacements with coronary artery bypass graft operations. The number of years in excess of age 55 was a significant multivariate predictor of mortality for all six groups of patients. Shock was a significant predictor for five of the six groups, and in each of those groups it was the risk factor with the highest odds ratio. CONCLUSIONS: Significant patient risk factors are relatively consistent across different types of valve replacement procedures. The probability of survival from valve surgical procedures is highly dependent on the patient's preoperative profile and the type of valve operation.

Aged↗
PubMed2000

Epidemiology of cholecystectomy and irritable bowel syndrome in a UK population.

BACKGROUND: Some patients with irritable bowel syndrome (IBS) may undergo unnecessary cholecystectomy. This paper describes the prevalence of cholecystectomy and IBS in a sample of British adults in Teesside. Associations between the two conditions and their relationship to consultation behaviour and socioeconomic status are described. The results are compared with those from Bristol in an attempt to determine the influence of service-related factors on the prevalence of cholecystectomy. METHODS: A postal questionnaire was sent to 4432 adults aged 20-69 years registered with six general practices. The Standard Occupational Classification was used as a proxy for socioeconomic status. RESULTS: In Teesside cholecystectomy was reported by 4.1 per cent of women and 1.3 per cent of men. Some 22.9 per cent of the women had IBS, and 10.5 per cent of men. Cholecystectomy was more common in patients with IBS (odds ratio 1.9 (95 per cent confidence interval 1.2-3.2); P < 0.01). The prevalence of cholecystectomy, of IBS and of consultation for symptoms of IBS was not influenced by socioeconomic status. CONCLUSION: Symptoms of IBS may cause diagnostic confusion and unproductive surgery. Cholecystectomy may cause IBS-like symptoms, a single underlying disorder may produce symptoms in both gastrointestinal and biliary tracts, or the associations might be due to a combination of these factors.

Adult↗
PubMed2000

Assessing the impact of total quality management and organizational culture on multiple outcomes of care for coronary artery bypass graft surgery patients.

OBJECTIVES: To assess the impact of total quality management (TQM) and organizational culture on a comprehensive set of endpoints of care for coronary artery bypass graft surgery (CABG) patients, including risk-adjusted adverse outcomes, clinical efficiency, patient satisfaction, functional health status, and cost of care. METHODS: Prospective cohort study of 3,045 eligible CABG patients from 16 hospitals using risk-adjusted clinical outcomes, functional health status, patient satisfaction, and cost measures. Implementation of TQM was measured by a previously validated instrument based on the Baldridge national quality award criteria. Organizational culture was measured by a previously validated 20-item instrument. Generalized estimating equations were used to control for potential selection bias, repeated measures, and intraclass correlation. RESULTS: A 2- to 4-fold difference in all major clinical CABG care endpoints was observed among the 16 hospitals, but little of this variation was associated with TQM or organizational culture. Patients receiving CABG from hospitals with high TQM scores were more satisfied with their nursing care (P = 0.005) but were more likely to have lengths of stay >10 days (P = 0.0003). A supportive group culture was associated with shorter postoperative intubation times (P = 0.01) but longer operating room times (P = 0.004). A supportive group culture was also associated with higher patient physical (P = 0.005) and mental (P = 0.01) functional health status scores 6 months after CABG. CONCLUSIONS: There was little effect of TQM and organizational culture on multiple endpoints of care for CABG patients. There is a need to examine further the relationships among individual professional skills and motivations, group and microsystem team processes, specifically tailored interventions, and organization-wide culture, decision support processes, and incentives. Assessing the impact of such multifaceted approaches is an important area for further research.

Adult↗
PubMed2000

Estimation of doubly labeled water energy expenditure with confidence intervals.

Bivariate regression is used to estimate energy expenditure from doubly labeled water data. Two straight lines are fitted to the logarithms of the enrichments of oxygen-18 and deuterium simultaneously as a bivariate regression, so that the correlations between the oxygen and deuterium regression coefficients can be estimated. Maximum likelihood methods are used to extend bivariate regression to unbalanced situations caused by missing observations and to include replicate laboratory determination from the same urine samples, even if one of the replicates is missing. Use of maximum likelihood allows the determination of a confidence interval for the energy expenditure based on the log likelihood surface rather than use of the propagation of variance methods for nonlinear transformations. The model is extended to include the subject's deviations from the two lines as a bivariate continuous-time first-order autoregression to allow for serial correlation in the observations. The analysis of data from two subjects, one without apparent serial correlation and one with serial correlation, is presented.

Deuterium↗
PubMed2000

Novel hepatoselective insulin analog: studies with a covalently linked thyroxyl-insulin complex in humans.

OBJECTIVE: To test whether a thyroxyl-insulin analog with restricted access to receptor sites in peripheral tissues displays relative hepatoselectivity in humans. RESEARCH DESIGN AND METHODS: Five normal human subjects received a subcutaneous bolus injection of either N(alphaBl) L-thyroxyl-insulin (Bl-T4-Ins) or NPH insulin in random order. Insulin kinetics, relative effects on hepatic glucose production, and peripheral glucose uptake were studied using euglycemic clamp and stable isotope [D-6,6-(2)H2]glucose) dilution techniques. Blood samples were taken for the determination of total immunoreactive insulin/analog concentrations and for liquid chromatography to assess the protein binding of the analog in the circulation. RESULTS: After subcutaneous administration, Bl-T4-Ins was well tolerated and rapidly absorbed. The analog had a long serum half-life and was highly protein bound (approximately 86%). Its duration of action, as judged by the duration of infusion of exogenous glucose to maintain euglycemia, was similar to that of NPH insulin. The effect of the analogs on hepatic glucose production was similar to that of NPH insulin, indicating equivalent hepatic potency. The analog demonstrated less effect on peripheral glucose uptake than NPH insulin (P = 0.025), had no effect on metabolic clearance rate of glucose, and exhibited a reduced capacity to inhibit lipolysis (P < 0.05). CONCLUSIONS: When injected subcutaneously into normal human subjects, Bl-T4-Ins is well tolerated, quickly absorbed, and highly protein bound, resulting in a long plasma halflife. This analog appears to have a hepatoselective action, and, therefore, has the potential to provide more physiological insulin action than the insulin preparations currently used.

Adult↗
PubMed2000

The epidemiology of hysterectomy and irritable bowel syndrome in a UK population.

The prevalence of hysterectomy in the UK general population has not been previously reported. In addition, although it is known that many women with irritable bowel syndrome (IBS) have had a hysterectomy, the relationship between these two conditions has never been quantified. A random community sample of 2238 women aged 20-69 from Teesside was surveyed to determine the prevalence of hysterectomy and of IBS, the relationship between these and the influence of socioeconomic status and consultation behaviour on these variables. We analysed data from 1718 women, 13.6% of whom had a hysterectomy, 22.9% had IBS and neither condition was related to socioeconomic status. More women with IBS reported having had a hysterectomy than did non-sufferers, odds ratio 1.6 (1.1-2.2), p < 0.01; this association was also unaffected by socioeconomic status and was not fully explained by consultation behaviour. This is the first study to determine the prevalence of hysterectomy in a UK general population. The procedure is common and the excess of hysterectomy among women with IBS is considerable. Possible explanations include misdiagnosis of IBS resulting in hysterectomy, IBS symptoms occurring as a result of hysterectomy, a single underlying disorder which produces symptoms in both gastrointestinal and genitourinary tracts, or a combination of these factors.

Adult↗
PubMed1999

Influence of pre-PTCA strategy and initial PTCA result in patients with multivessel disease: the Bypass Angioplasty Revascularization Investigation (BARI).

BACKGROUND: In PTCA patients with multivessel coronary artery disease, incomplete revascularization (IR) is the result of both pre-PTCA strategy and initial lesion outcome. The unique contribution of these components on long-term patient outcome is uncertain. METHODS AND RESULTS: From the Bypass Angioplasty Revascularization Investigation (BARI), 2047 patients who underwent first-time PTCA were evaluated. Before enrollment, all significant lesions were assessed by the PTCA operator for clinical importance and intention to dilate. Complete revascularization (CR) was defined as successful dilatation of all clinically relevant lesions. Planned CR was indicated in 65% of all patients. More lesions were intended for PTCA in these patients compared with those with planned IR (2.8 versus 2.1). Successful dilatation of all intended lesions occurred in 45% of patients with planned CR versus 56% with planned IR (P<0. 001). In multivariable analysis, planned IR (versus planned CR), initial lesions attempted (not all versus all intended lesions attempted), and initial lesion outcome (not all versus all attempted lesions successful) were unrelated to 5-year risk of cardiac death or death/myocardial infarction but were all independently related to risk of CABG. CONCLUSIONS: Overall, a pre-PTCA strategy of IR in BARI-like patients appears comparable to a strategy of CR except for a higher need for CABG. Whether the use of new devices may attenuate the elevated risk of CABG in patients with multivessel disease and planned IR remains to be determined.

Aged↗
PubMed1999

Mortality and need for reoperation in patients with mild-to-moderate asymptomatic aortic valve disease undergoing coronary artery bypass graft alone.

BACKGROUND: Patients presenting for coronary artery bypass graft (CABG) surgery may have concurrent asymptomatic aortic stenosis (AS) or aortic insufficiency (AI). This retrospective study was performed to evaluate outcomes in patients with aortic valve disease undergoing CABG with or without aortic valve replacement (AVR). METHODS: Study groups included 414 patients undergoing combined AVR and CABG (AVR-CABG group) and 62 patients with asymptomatic mild-to-moderate AS, AI, or both undergoing CABG but not AVR (CABG group). End points included 30-day mortality rate, time to cardiac mortality, time to all-cause mortality, and time to aortic valve reoperation. Reoperation refers to surgery for replacement of the native aortic valve in the CABG group or replacement of the prosthetic aortic valve in the AVR-CABG group. Important patient characteristics affecting outcomes were determined by using Cox proportional-hazard analysis. These variables were then included in multivariable analyses by using logistic regression analysis and Cox proportional-hazard modeling to compare outcomes between each patient group. RESULTS: No difference was seen in any of the mortality end points between the CABG group and the AVR-CABG group after controlling for significant differences between the groups. However, the need for reoperation for AVR was significantly higher for the CABG group than the AVR-CABG group. For patients followed for up to 6 years, the estimated need for aortic valve reoperation was 24.3% in the CABG group versus 3% in the AVR-CABG group. CONCLUSION: On the basis of these results, patients with asymptomatic AS or AI should be considered for AVR at the time of CABG.

Aged↗
PubMed1999

A comparison of three-year survival after coronary artery bypass graft surgery and percutaneous transluminal coronary angioplasty.

OBJECTIVES: The purpose of this study was to compare 3-year risk-adjusted survival in patients undergoing coronary artery bypass graft (CABG) surgery and percutaneous transluminal coronary angioplasty. BACKGROUND: Coronary artery bypass graft surgery and angioplasty are two common treatments for coronary artery disease. For referral purposes, it is important to know the relative pattern of survival after hospital discharge for these procedures and to identify patient characteristics that are related to survival. METHODS: New York's CABG surgery and angioplasty registries were used to identify New York patients undergoing CABG surgery and angioplasty from January 1, 1993 to December 31, 1995. Mortality within 3 years of undergoing the procedure (adjusted for patient severity of illness) and subsequent revascularization within 3 years were captured. Three-year mortality rates were adjusted using proportional hazards methods to account for baseline differences in patients' severity of illness. RESULTS: Patients with one-vessel disease with the one vessel not involving the left anterior descending artery (LAD) or with less than 70% LAD stenosis had a statistically significantly longer adjusted 3-year survival with angioplasty (95.3%) than with CABG surgery (92.4%). Patients with proximal LAD stenosis of at least 70% had a statistically significantly longer adjusted 3-year survival with CABG surgery than with angioplasty regardless of the number of coronary vessels diseased. Also, patients with three-vessel disease had a statistically significantly longer adjusted 3-year survival with CABG surgery regardless of proximal LAD disease. Patients with other one-vessel or two-vessel disease had no treatment-related differences in survival. CONCLUSIONS: Treatment-related survival benefit at 3-years in patients with ischemic heart disease is predicted by the anatomic extent and specific site of the disease, as well as by the treatment chosen.

Aged↗
PubMed1999

Is a strategy of intended incomplete percutaneous transluminal coronary angioplasty revascularization acceptable in nondiabetic patients who are candidates for coronary artery bypass graft surgery? The Bypass Angioplasty Revascularization Investigation (BARI).

OBJECTIVES: Our objective was to determine whether a strategy of intended incomplete percutaneous transluminal coronary angioplasty revascularization (IR) compromises long-term patient outcome. BACKGROUND: Complete angioplasty revascularization (CR) is often not planned nor attempted in patients with multivessel coronary disease, and the extent to which this influences outcome is unclear. METHODS: Before randomization, in the Bypass Angioplasty Revascularization Investigation, all angiograms were assessed for intended CR or IR via angioplasty. Outcomes were compared among patients with IR intended if assigned to angioplasty, randomized to coronary artery bypass graft surgery (CABG) versus angioplasty; and within angioplasty patients only, among patients with IR versus CR intended. RESULTS: At 5 years, there was a trend for higher overall (88.6% vs. 84.0%) and cardiac survival (94.5% vs. 92.1%) in CABG versus angioplasty patients with IR intended. The excess mortality in angioplasty patients occurred solely in diabetic subjects; overall and cardiac survival were similar among nondiabetic CABG and angioplasty patients. Freedom from myocardial infarction (MI) at 5 years was higher in nondiabetic CABG versus angioplasty patients (92.4% vs. 85.2%, p = 0.02), vet was similar to the rate observed (85%) in nondiabetic CABG and angioplasty patients with CR intended. Five-year rates of death, cardiac death, repeat revascularization and angina were similar in all angioplasty patients with IR versus CR intended. However, a trend for greater freedom from subsequent CABG was seen in CR patients (70.3% vs. 64.0%, p = 0.08). CONCLUSIONS: Intended incomplete angioplasty revascularization in nondiabetic patients with multivessel disease who are candidates for both angioplasty and CABG does not compromise long-term survival; however, subsequent need for CABG may be increased with this strategy. Whether the risk of long-term MI is also increased remains uncertain.

Aged↗
PubMed1999

Alosetron relieves pain and improves bowel function compared with mebeverine in female nonconstipated irritable bowel syndrome patients.

BACKGROUND: Irritable bowel syndrome is one of the most common gastrointestinal disorders, yet no therapy convincingly controls the multiple symptoms of this syndrome. AIM: To compare the efficacy and tolerability of the new 5-HT3-receptor antagonist alosetron and the smooth muscle relaxant mebeverine in a double-blind, multicentre, randomized trial. METHODS: Six hundred and twenty-three nonconstipated females with irritable bowel syndrome were randomized to receive alosetron 1 mg twice daily (n=319) or mebeverine 135 mg three times daily (n=304) for 12 weeks, followed by a 4-week post-treatment period. The primary efficacy end-point was monthly responders for adequate relief of irritable bowel syndrome related abdominal pain and discomfort (defined as patients reporting adequate relief on at least 2 out of 4 weeks). Secondary end-points included assessments of bowel function, including urgency, stool frequency and stool consistency. RESULTS: There were significantly more responders in the alosetron group compared with mebeverine at months 2 and 3 (P < 0.01). Compared with mebeverine, the alosetron group experienced significant decreases in proportion of days with urgency and mean stool frequency, and had firmer stools within 1 week of starting treatment. A similar proportion of patients reported adverse events in the two treatment groups. CONCLUSIONS: In nonconstipated female irritable bowel syndrome patients, alosetron is significantly more effective than mebeverine in improving symptoms.

Adolescent↗