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Biomedical subjects

S Stewart

Publications and source records attributed to S Stewart.

At least 37 records · Page 2Linked to original sources

Inter-observer variation between pathologists in diffuse parenchymal lung disease.

BACKGROUND: There have been few inter-observer studies of diffuse parenchymal lung disease (DPLD), but the recent ATS/ERS consensus classification provides a basis for such a study. METHODS: A method for categorising numerically the percentage likelihood of these differential diagnoses was developed, and the diagnostic confidence of pathologists using this classification and the reproducibility of their diagnoses were assessed. RESULTS: The overall kappa coefficient of agreement for the first choice diagnosis was 0.38 (n = 133 biopsies), increasing to 0.43 for patients (n = 83) with multiple biopsies. Weighted kappa coefficients of agreement, quantifying the level of probability of individual diagnoses, were moderate to good (mean 0.58, range 0.40-0.75). However, in 18% of biopsy specimens the diagnosis was given with low confidence. Over 50% of inter-observer variation related to the diagnosis of non-specific interstitial pneumonia and, in particular, its distinction from usual interstitial pneumonia. CONCLUSION: These results show that the ATS/ERS classification can be applied reproducibly by pathologists who evaluate DPLD routinely, and support the practice of taking multiple biopsy specimens.

Biopsy↗

Evaluation and use of three cowside tests for detection of subclinical ketosis in early postpartum cows.

The objective was to evaluate the performance of 3 cowside diagnostic tests for detection of subclinical ketosis, defined as a serum beta-hydroxybutyrate (BHBA) concentration >or=1400 micromol/L. On 16 d over a 5-mo period, samples of serum, milk, and urine were collected on a large dairy facility from cows of all parities between 2 and 15 DIM. The sample proportion of subclinical ketosis was 7.6% (n = 859 samples from 545 cows). The KetoCheck powder (Great States Animal Health, St. Joseph, MO) detecting acetoacetate in milk samples was very specific (99%) but poorly sensitive (41%). Respective sensitivities and specificities of the Ketostix strip detecting acetoacetate in urine samples (Bayer Corporation, Elkhart, IN) were 78 and 96% with a cut-off point of "small", or 49 and 99% with a cut-off of "moderate." The KetoTest strip (Sanwa Kagaku Kenkyusho Co. Ltd., Nagoya, Japan) using milk samples had a sensitivity and specificity of 73 and 96% with a cut-off of 100 micromol of BHBA/L or 27 and 99% with a cut-off of 200 micromol of BHBA/L. On average, use of the Ketostix at the "small" cut-off point or the KetoTest at 100 micromol/L would result in no more than 3 or 4 false positives per 100 cows screened, with prevalence levels ranging from 5 to 30%, whereas the number of false negatives would range from one false negative at 5% prevalence to 7 or 8 false negatives at 30% prevalence. Either the Ketostix or KetoTest strips would provide acceptable results for screening individual cows on commercial dairies to detect subclinical ketosis. Over this prevalence range, the KetoCheck powder test would have limited application as a screening test. Despite only one false positive per 100 animals screened, false negatives resulting from screening with the KetoCheck test would be too frequent, ranging from 3 false negatives at 5% prevalence to 18 at 30% prevalence in a population of 100 tested cows. Finally, given their relative imprecision, use of any of these individual cowside tests to estimate herd prevalence must be done cautiously, especially when only a small number of animals are sampled.

3-Hydroxybutyric Acid↗

Agricultural environmental management; case studies from theory to practice.

Six farms were examined, each from a different sector of Scottish agriculture. Surveys were carried out to identify both diffuse pollution risks and options for habitat conservation and enhancement. Financial data were also gathered to determine the current sources of farm income, both from sale of produce and from grants. Whole farm plans were produced aimed at bringing about reductions in diffuse pollution to water, soil and air and also habitat improvements. The assembled information was used to devise a possible agri-environment grant scheme to aid the implementation of the whole farm plans.

Agriculture↗

Heart failure and the aging population: an increasing burden in the 21st century?

BACKGROUND: Despite an overall decline in age adjusted mortality from coronary heart disease in developed countries, the number of patients with heart failure may be increasing. OBJECTIVE: To project the future burden of heart failure in Scotland from contemporary epidemiological data. METHODS: Scotland, like many industrialised countries, has an aging though numerically stable population (5.1 million). Current estimates of prevalence, general practice (GP) consultation rates, and hospital admission rates related to heart failure were applied to the whole Scottish population. These estimates were then projected over the period 2000 to 2020, on an age and sex specific basis, using expected changes in the age structure of the Scottish population. RESULTS: There are currently estimated to be 40 000 men and 45 000 women aged > or = 45 years with heart failure in Scotland. On the basis of population changes alone, these figures will rise in men and women by 2300 (6%) and 1500 (3%) by year 2005, and by 12 300 (31%) and 7800 (17%) in the longer term (2020), respectively. On the same basis, the annual number of male and female GP visits is likely to rise by 6400 (6%) and 2500 (2%) by year 2005, and by 35 200 (40%) and 17 300 (16%) in the longer term (124 000 and 126 000 visits), respectively. In the year 2000 about 3500 men and 4300 women in Scotland had an incident hospital admission for heart failure. By the year 2020 these figures are likely to increase by 52% (1800 more) and 16% (717 more) in men and women, respectively. If recent trends in short term case fatality rates continue to improve, the number of men who survive this event will increase by 59% (1700 more). Overall, by 2020 the annual number of male and female hospital admissions associated with a principal diagnosis of heart failure is expected to increase by 34% (from 5500 to 7500) and by 12% (from 7800 to 8500), respectively. CONCLUSIONS: Unless rapid and major changes occur in the incidence of heart failure, the burden of this disorder will continue to increase in both primary and secondary care over the next two decades. The greatest increase is likely to occur in men. Future health service planning must take this into account.

Age Distribution↗

The current cost of angina pectoris to the National Health Service in the UK.

OBJECTIVE: To calculate the cost of angina pectoris to the UK National Health Service (NHS) in the year 2000. METHODS: Calculation of the cost of hospital admissions, revascularisation procedures, hospital outpatient consultations, general practice (GP) consultations, and prescribed drug treatment. RESULTS: 634 000 individuals (1.1% of the UK population) consulted GPs 2.35 million times, costing pound 60.5 million. They required 16.0 million prescriptions (cost pound 80.7 million) and 254 000 hospital outpatient referrals (cost pound 30.4 million). There were 149 000 hospital admissions, 117 000 coronary angiograms, 21 400 coronary artery bypass operations, 17 700 percutaneous coronary interventions, and 516 000 outpatient visits, at a cost of pound 208.4 million, pound 69.9 million, pound 106.2 million, pound 60.7 million, and pound 52.2 million, respectively. The direct cost of angina was therefore pound 669 million (1.3% of total NHS expenditure), with hospital bed occupancy and procedures accounting for 32% and 35% of this total, respectively. CONCLUSIONS: Angina is a common and costly public health problem. It consumed over 1% of all NHS expenditure in the year 2000, mainly because of hospital bed occupancy and revascularisation procedures. This is likely to be a conservative estimate of its true cost.

Ambulatory Care↗

Can a busy abortion service cope with a screen-and-treat policy for Chlamydia trachomatis infection?

In order to determine the effectiveness of a screen-and-treat policy for Chlamydia trachomatis within a busy medical and surgical abortion service, a retrospective audit was conducted of 2058 women undergoing induced abortion over 12 months. The prevalence of C. trachomatis was 6%. Although most positive results were available before a surgical abortion (97%), only 76% were available before a medical abortion (P = 0.007). This resulted in more treatment delays in the medical group (P = 0.04). Although the majority of women (94% surgical and 84% medical) were seen by genitourinary medicine, only one-quarter of partners attended for contact tracing. The current screen-and-treat policy has been shown to be deficient in several areas. Of most concern are the treatment delays with medical abortion, which may be due to the faster 'processing' of women since this method is only available at < or = 9 weeks' gestation. Such challenges to a screen-and-treat policy, are likely to become more common as medical abortion becomes more widely adopted.

Abortion, Legal↗

Effectiveness of an internal teat seal in the prevention of new intramammary infections during the dry and early-lactation periods in dairy cows when used with a dry cow intramammary antibiotic.

The objectives of this study were to determine the effect of infusion with an internal teat seal at dry off, when used as an adjunct to long-acting antibiotic infusion at dry off, on the risk for acquiring a new intramammary infection (IMI) during the dry period, prevalence of IMI and linear score (LS) after calving, and risk for experiencing a clinical mastitis event between dry off and 60 DIM. A total of 437 cows from 2 dairy herds, with no clinical mastitis and 4 functional quarters, were enrolled at dry off. Prior to the final milking, all quarters were sampled for bacteriological culture and SCC analysis. After milking, all 4 quarters were infused with a commercially available long-acting dry cow antibiotic. Two contralateral quarters were then infused with an internal teat seal (Orbeseal, Pfizer Animal Health, New York). Following calving the teat seal was stripped out at first milking. Duplicate milk samples were collected between 1 to 3 DIM and again between 6 to 8 DIM for culture and SCC analysis. Quarters treated with Orbeseal had significantly lower prevalence of IMI at 1 to 3 DIM (tx = 22.8%, control = 29.1%), had significantly fewer quarters that acquired a new IMI between dry off and 1 to 3 DIM (tx = 20.2%, control = 25.4%), and had significantly fewer quarters affected by a clinical mastitis event between dry off and 60 DIM (tx = 5.9%, control = 8.0%). Multivariable analysis showed a significant effect of treatment, with treated quarters being 30% less likely to develop a new IMI between dry off and 1 to 3 DIM, 31% less likely to have an IMI present at 1 to 3 DIM, 33% less likely to experience a clinical mastitis event between dry off and 60 DIM, and having significantly lower linear score measures at 1 to 3 DIM and 6 to 8 DIM, compared with control quarters.

Animals↗

Trends in case-fatality in 22968 patients admitted for the first time with atrial fibrillation in Scotland, 1986-1995.

BACKGROUND: Although atrial fibrillation (AF) is an important cause of cardiovascular morbidity and mortality there is a paucity of data describing hospitalisation rates and case-fatality associated with this common arrhythmia. This study examines recent trends in first-ever hospitalisations for AF in Scotland. METHODS: Using the linked Scottish Morbidity Record Scheme, we identified all 22968 patients admitted to Scottish hospitals for the first time with a principal diagnosis of AF between 1986 and 1995. For each calendar year we calculated short (30-day) and medium (31 day to 2 years) case-fatality rates. Adjusting for each patient's age, sex, deprivation status, concurrent diagnoses and prior hospitalisation status, we examined whether case-fatality rates had significantly improved during this 10-year period. RESULTS: Between 1986 and 1995 the number of men hospitalised for the first time with AF increased by 926 (125%) to 1730 per annum and the number of women and by 875 (105%) to 1712 (both P<0.001). Hospitalisation rates increased from 0.31 to 0.70/1000 men and from 0.32 to 0.65/1000 women (both P<0.001). By the end of this period the proportion of men had increased from 48 to 50%. In both sexes, the median age of patients rose--in men from 66 to 68 years and in women from 74 to 75 years (both P<0.01). Despite the increasing age of patients and greater comorbidity, short-term (30-day) case-fatality declined from 4.0 to 3.1% in men (P<0.001) and 4.1 to 3.8% (P<0.01) in women. Similarly, medium-term (31-day to 2-year) case-fatality fell from 25 to 22% in men and 27 to 25% (both P<0.001) in women. Adjusting for the age, sex, extent of deprivation, secondary diagnoses and prior hospitalisation of hospitalised patients, we found that the risk of short-term case-fatality in the 1995 male and female cohort significantly declined by 21% (P<0.05) and 24% (P<0.05), respectively, in comparison to the 1986 cohort. The adjusted risk of case-fatality in the medium term also declined significantly in men by 30% (P<0.05) over this period and by 20% (P<0.05) in women relative to 1986. CONCLUSION: The number of first-ever hospitalisations for AF has increased twofold during the 10-year period 1986-1995. Although the age of patients has progressively increased during this period, short and medium case-fatality rates have declined, especially in men. This may partly reflect better treatment of AF. However, changing admission thresholds and other factors could also have led to an apparent improvement in prognosis. Nevertheless, medium-term case fatality remains substantial after a first ever admission to hospital with AF.

Aged↗

Retrofitting of a satellite repeat DNA-based murine artificial chromosome (ACes) to contain loxP recombination sites.

A satellite DNA-based mammalian artificial chromosome (ACes) was generated and subsequently modified by targeting of a loxP-red fluorescent protein (RFP) expression cassette via homologous recombination into a ribosomal DNA (rDNA)-containing locus. Clones containing correctly targeted ACes were identified by PCR from populations of RFP-expressing cells enriched by FACS sorting and were further characterized by fluorescent in situ hybridization. The targeted ACes maintained its ability to be purified to near homogeneity. Studies are currently underway to further characterize the functionality, carrying capacity, stability and transfectability of this modified ACes.

Animals↗

Evaluation of health-care worker vaccination in a tertiary Australian hospital.

BACKGROUND: Maintaining a complete vaccination status for health-care workers (HCWs) is important to minimize morbidity among staff and patients. Despite recommendations from public-health authorities to support this process, not all hospitals have adequate policy and practice in place. AIMS: To independently assess the implementation and impact of a new policy aimed at improving HCW vaccination coverage in a tertiary Victorian hospital. METHODS: Two cross-sectional surveys were conducted by telephone in July and October 2000 for a random sample of HCWs, before and after the introduction of the policy. These surveys examined knowledge, attitudes and practices surrounding vaccination and self-reported vaccination status. Policy implementation was assessed by ascertaining completion of compulsory vaccination status forms and attendance at suggested appointments to review vaccination status. RESULTS: Only 19% of 269 HCWs reported a complete vaccination status at baseline. Most (76%) had not heard of or seen vaccination guidelines and 39% kept written vaccination records. This was despite a belief in the importance of vaccination (94%) and a willingness to update if necessary (96%). At follow up there was no improvement in any outcome. Only 11/26 (42%) newly employed HCWs surveyed received and returned compulsory vaccination status forms. Of the few HCWs who attended recommended vaccination appointments, all received vaccinations. CONCLUSIONS: HCW vaccination coverage and knowledge of vaccination requirements were poor. Although attending a physician to discuss vaccination status did result in vaccination, few HCWs made such an appointment. While policy development is an important first step towards improving vaccination coverage, effective implementation requires ongoing evaluation, adequate resources and HCW education.

Adult↗

Substantial between-hospital variation in outcome following first emergency admission for heart failure.

BACKGROUND: Following hospitalization with a range of cardiovascular disorders, substantial variation has been noted in clinical outcome, both between and within countries. OBJECTIVES: To examine the variation, between hospitals, in the clinical outcomes of death and readmission following hospitalization with heart failure in Scotland. Setting All 29 acute hospitals in Scotland with more than 200 beds. PATIENTS: All 31 452 patients discharged from these hospitals between January 1990 and December 1995 with a first-ever, primary, diagnosis at discharge/death of heart failure. ANALYSIS: An analysis of the Scottish database of discharge summaries linking index admissions with subsequent admissions and deaths. Death rates and readmission rates were adjusted for baseline age, co-morbidity and socio-economic status and were calculated at different time periods (inpatient, 30 days, 1 year). Rates were calculated separately for large teaching hospitals (n=6, category A), large general hospitals with specialist units (n=8, category B) and medium sized general hospitals with limited specialist units (n=15 category C). RESULTS: A total of 31 452 patients were discharged between 1990-1995 - 10 219 (33%), 9735 (31%) and 11 498 (37%) to category A, B and C hospitals, respectively. The national, average, inpatient case fatality rate was 15.3%, ranging, in individual hospitals, from the lowest rate of 8.5% to the highest rate of 23.4%. The average 1 year case fatality rate was 42.4%, ranging between 35.3% and 50.8%. A similar two- to threefold variation was found in hospital readmission rates - thus the average 30 day readmission rate was 5.3% (lowest 3.3%, highest 7.3%). This variation, in both case-fatality and readmission rates, was apparent within all three groups of hospitals and persisted after adjustment for the baseline factors outlined above. CONCLUSIONS: A patient admitted to one Scottish hospital with heart failure may be two to three times more likely to die or be readmitted, both in the short and longer term, compared to a patient admitted to another hospital. Although we may not have accounted for some sources of variation, it is both surprising and disturbing that large, statistically significant, differences in adjusted death and readmission rates can apparently exist for such an important condition in a relatively small country with generally homogenous health care provision. Further, detailed investigation of this apparent variation is required.

Age Factors↗

An economic analysis of specialist heart failure nurse management in the UK; can we afford not to implement it?

AIMS: Hospital activity represents the major component of health care expenditure related to heart failure. This study evaluated the economic impact of applying specialist nurse management programmes that limit heart failure-related hospital readmissions within a whole population. METHODS: Using a reliable and validated estimate of the current level and cost of heart failure-related hospital activity in the U.K., we determined the thresholds at which the actual cost of establishing and applying a national service based on three different models of specialist nurse management would be equal to the 'cost' of bed utilization associated with preventable hospital readmissions in the year 2000. The three models of care examined were home-based, clinic-based or a combination of home plus clinic-based, post-discharge follow-up. The potential impact of this service was based on a U.K.-wide caseload of 122,000 patients discharged to home with a discharge diagnosis of congestive heart failure in that year. RESULTS: Based on heart failure-specific patterns of hospital activity, we estimate that 47,000 of these 122,000 patients would normally accumulate a total of 594000 days of associated hospital stay from 49,000 readmissions (for any reason) within 1 year of hospital discharge. The cost of these admissions to the National Health Service was calculated at 166.2 million pounds sterling. Taking into account other costs associated with such hospital activity (e.g. general practice and hospital outpatient visits) each 10% reduction in recurrent bed utilization would be associated with 18.0 million ponds sterling in cost savings. Alternatively, the cost of applying a U.K.-wide programme of home-, clinic- or home plus clinic-based follow-up was calculated to be 69.4 pounds sterling, 73.1 pounds sterling and 72.5 million pounds sterling per annum, respectively. The relative thresholds at which generated 'cost-savings' would equal the cost of applying these programmes of care would therefore be a 38.5%, 40.6% and 40.3% reduction in recurrent bed utilization, respectively. If, as expected, a home-based programme of specialist nurse management reduced recurrent bed utilization by 50% or more, annual savings equivalent to 169,000 pounds sterling per 1000 patients treated would be generated. CONCLUSIONS: This is the first study to examine the economic consequences of applying a specialist nurse-mediated, post-discharge management service for heart failure within a whole population. Our findings suggest that such a service will not only improve quality of life and reduce readmissions in patients with congestive heart failure, but also reduce costs and improve the efficiency of the health care system in doing so.

Community Health Nursing↗

Beneficial clinical effects of perhexiline in patients with stable angina pectoris and acute coronary syndromes are associated with potentiation of platelet responsiveness to nitric oxide.

AIMS: To examine whether the prophylactic antianginal agent perhexiline potentiates platelet responsiveness to nitric oxide (NO) in patients with stable angina pectoris (SAP) and acute coronary syndromes (ACS: unstable angina pectoris or non-Q-wave myocardial infarction). METHODS AND RESULTS: Blood samples were obtained from patients before and after initiation of treatment with perhexiline. ADP-induced platelet aggregation and its inhibition by the NO donor sodium nitroprusside (SNP) were determined via impedance aggregometry in whole blood (WB) and platelet-rich plasma (PRP). Intraplatelet cGMP content was assayed by RIA, and superoxide (O(2)(-)) level by lucigenin-derived chemiluminescence. In patients with ACS not receiving perhexiline (n=12), platelet responsiveness to SNP did not vary significantly over the first 3 days post admission to hospital. Therapy with perhexiline for 3 days was associated with increases in SNP-induced inhibition of aggregation from 29+/-2% to 43+/-4% (n=50,P <0.001) in WB and from 20+/-5% to 42+/-7% (n=12, P<0.01) in PRP. Resolution of symptomatic ischaemia (n=39) was associated with significantly greater (P<0.01) increases than non-resolution (n=11). Similar increases in SNP responsiveness (P<0.001) occurred following institution of perhexiline therapy in patients with SAP (n=30), associated with a 85% decrease in anginal frequency. Treatment with perhexiline potentiated the cGMP-elevating effects of SNP in platelets (n=9,P =0.03). Although perhexiline did not alter whole blood O(2)(-) concentration ex vivo, it inhibited (P<0.01) O(2)(-) release from neutrophils in vitro. CONCLUSION: Perhexiline potentiates platelet responsiveness to NO both in SAP and ACS patients; in the latter group this improvement was predictive of resolution of ischaemic symptoms. The predominant mechanism of perhexiline effect is an increase in platelet cGMP responsiveness. Perhexiline also may reduce the potential for NO clearance by neutrophil-derived O(2)(-).

Aged↗

Characterising doctor-parent communication in counselling for impending preterm delivery.

OBJECTIVE: To examine the counselling of women admitted to hospital in preterm labour. Such women and their partners are often asked to participate in difficult decisions including mode of delivery, fetal monitoring, and resuscitation. STUDY DESIGN: Questionnaire based descriptive study. STUDY SETTING: A tertiary level perinatal referral centre. PATIENTS: Forty-nine women in preterm labour at 22-30 weeks gestation, admitted in two separate periods between March 1997 and May 1999. INTERVENTION AND OUTCOME MEASURE: Within 24 hours of counselling, parents were asked to complete a questionnaire assessing recall of the management plan, desire for involvement in decision making, anxiety, and feelings of control over their health. A parallel questionnaire was completed by the clinicians. RESULTS: Parents and clinicians on recall agreed well about obstetric issues but poorly about neonatal issues. Overall 27% of parents felt: "I would prefer to have the doctors advise me, rather than asking me to decide". In 79% of cases, clinicians believed parents preferred advice rather than to make decisions, but in 45% of these, they misidentified those who wished to make their decisions. Anxiety levels for one third of the mothers were high, and associated with poorer concordance of recall between parents and clinicians. CONCLUSIONS: Serious deficiencies exist in parent-clinician encounters during extremely preterm labour. Concordance between parents and clinicians is poor and anxiety very high. A quarter of parents appear to prefer to relinquish decision making autonomy, but clinicians cannot correctly identify this subgroup. Standardised counselling in the perinatal period, using formal decision aids, should be investigated.

Communication↗

Effects of automatic cluster remover settings on average milking duration, milk flow, and milk yield.

A crossover study design was used in five commercial dairy herds to study the effect of altering the switch point settings for automatic cluster remover units on the average duration of unit attachment, milk flow, and milk yield. Automatic cluster remover switch point settings were alternated, for 1-wk periods, between 0.50 and 0.64 kg/min (1.1 and 1.4 lb/min) in one herd and between 0.73 and 0.82 kg/min (1.6 and 1.8 lb/min) in the four remaining herds. Parlor data were captured at 329 separate milking sessions (range 39 to 92 per herd), representing 239,393 individual cow milkings. While increasing the automatic cluster remover switch point setting was not associated with a change in average milking duration in one herd, it had the effect of significantly reducing the average milking duration by between 10.2 and 15.6 s per cow in the remaining four herds. Milk flow was significantly increased at higher switch point settings for all five herds. Higher automatic cluster remover switch point settings did not have a negative effect on milk yield in any of the herds studied and, in fact, were associated with increased milk yield in two of the five herds. Decreasing milking duration while either maintaining or increasing the volume of milk harvested should ultimately lead to improved milking efficiency and parlor performance. Modifying systems to increase automatic cluster remover switch point settings offers an important potential opportunity to increase parlor efficiency in commercial dairy herds.

Animals↗

Age, sex, and social trends in out-of-hospital cardiac deaths in Scotland 1986-95: a retrospective cohort study.

BACKGROUND: Most deaths from coronary heart disease occur out of hospital. Hospital patients face social, age, and sex inequalities. Our aim was to examine inequalities and trends in out-of-hospital cardiac deaths. METHODS: We used the Scottish record linked database to identify all deaths from acute myocardial infarction that occurred in Scotland (population 5.1 million), in 1986-95. We have compared population-based death rates for men and women across age and social groups. FINDINGS: Between 1986 and 1995, 83365 people died from acute myocardial infarction, out of hospital and without previous hospital admission (44655 men, 38710 women); and 117749 were admitted with a first acute myocardial infarction, of whom 37020 died within 1 year. Thus, out-of-hospital deaths accounted for 69.2% (95% CI 69.0-69.5) of all 120385 deaths. Out-of-hospital deaths, measured as a proportion of all acute myocardial infarction events (deaths plus first hospital admissions), increased with age, from 20.1% (19.2-21.0) in people younger than 55 years, to 62.1% (61.3-62.9) in those older than 85 years. Population-based out-of-hospital mortality rates fell by a third in men and by a quarter in women. Mean yearly falls were larger in people aged 55-64 years (5.6% per year in men, 3.7% in women), than in those older than 85 years (2.5% in men and women). Mortality rates were substantially higher in deprived socioeconomic groups than in affluent groups, especially in people younger than 65 years. INTERPRETATION: These inequalities in age, sex, and socioeconomic class should be actively addressed by prevention strategies for coronary heart disease.

Age Distribution↗

Stable angina and acute coronary syndromes are associated with nitric oxide resistance in platelets.

OBJECTIVES: The study examined possible clinical determinants of platelet resistance to nitric oxide (NO) donors in patients with stable angina pectoris (SAP) and acute coronary syndromes (ACS), relative to nonischemic patients and normal subjects. BACKGROUND: We have shown previously that platelets from patients with SAP are resistant to the antiaggregating effects of nitroglycerin (NTG) and sodium nitroprusside (SNP). METHODS: Extent of adenosine diphosphate (1 micromol/liter)-induced platelet aggregation (impedance aggregometry in whole blood) and inhibition of aggregation by NTG (100 micromol/liter) and SNP (10 micromol/liter) were compared in normal subjects (n = 43), nonischemic patients (those with chest pain but no fixed coronary disease, (n = 35) and patients with SAP (n = 82) or ACS (n = 153). Association of NO resistance with coronary risk factors, coronary artery disease (CAD), intensity of angina and current medication was examined by univariate and multivariate analyses. RESULTS: In patients with SAP and ACS as distinct from nonischemic patients and normal subjects, platelet aggregability was increased (both p < 0.01), and inhibition of aggregation by NTG and SNP was decreased (both p < 0.01). Multivariate analysis revealed that NO resistance occurred significantly more frequently with ACS than with SAP (odds ratio [OR] 2.3:1), and was less common among patients treated with perhexiline (OR 0.3:1) or statins (OR 0.45:1). Therapy with other antianginal drugs, extent of CAD, intensity of angina and coronary risk factors were not associated with variability in platelet responsiveness to NO donor. CONCLUSIONS: Patients with symptomatic ischemic heart disease, especially ACS, exhibit increased platelet aggregability and decreased platelet responsiveness to the antiaggregatory effects of NO donors. The extent of NO resistance in platelets is not correlated with coronary risk factors. Pharmacotherapy with perhexiline and/or statins may improve platelet responsiveness to NO.

Acute Disease↗