F.G.R. Fowkes

Aspirin for Prevention of Cardiovascular Events in a General Population Screened for a Low Ankle Brachial Index: A Randomized Controlled Trial

CONTEXT A low ankle brachial index (ABI) indicates atherosclerosis and an increased risk of cardiovascular and cerebrovascular events. Screening for a low ABI can identify an asymptomatic higher risk group potentially amenable to preventive treatments. OBJECTIVE To determine the effectiveness of aspirin in preventing events in people with a low ABI identified on screening the general population. DESIGN, SETTING, AND PARTICIPANTS The Aspirin for Asymptomatic Atherosclerosis trial was an intention-to-treat double-blind randomized controlled trial conducted from April 1998 to October 2008, involving 28,980 men and women aged 50 to 75 years living in central Scotland, free of clinical cardiovascular disease, recruited from a community health registry, and had an ABI screening test. Of those, 3350 with a low ABI (< or = 0.95) were entered into the trial, which was powered to detect a 25% proportional risk reduction in events. INTERVENTIONS Once daily 100 mg aspirin (enteric coated) or placebo. MAIN OUTCOME MEASURES The primary end point was a composite of initial fatal or nonfatal coronary event or stroke or revascularization. Two secondary end points were (1) all initial vascular events defined as a composite of a primary end point event or angina, intermittent claudication, or transient ischemic attack; and (2) all-cause mortality. RESULTS After a mean (SD) follow-up of 8.2 (1.6) years, 357 participants had a primary end point event (13.5 per 1000 person-years, 95% confidence interval [CI], 12.2-15.0). No statistically significant difference was found between groups (13.7 events per 1000 person-years in the aspirin group vs 13.3 in the placebo group; hazard ratio [HR], 1.03; 95% CI, 0.84-1.27). A vascular event comprising the secondary end point occurred in 578 participants (22.8 per 1000 person-years; 95% CI, 21.0-24.8) and no statistically significant difference between groups (22.8 events per 1000 person-years in the aspirin group vs 22.9 in the placebo group; HR, 1.00; 95% CI, 0.85-1.17). There was no significant difference in all-cause mortality between groups (176 vs 186 deaths, respectively; HR, 0.95; 95% CI, 0.77-1.16). An initial event of major hemorrhage requiring admission to hospital occurred in 34 participants (2.5 per 1000 person-years) in the aspirin group and 20 (1.5 per 1000 person-years) in the placebo group (HR, 1.71; 95% CI, 0.99-2.97). CONCLUSION Among participants without clinical cardiovascular disease, identified with a low ABI based on screening a general population, the administration of aspirin compared with placebo did not result in a significant reduction in vascular events. TRIAL REGISTRATION isrctn.org Identifier: ISRCTN66587262.

Blood viscosity, fibrinogen, and activation of coagulation and leukocytes in peripheral arterial disease and the normal population in the Edinburgh Artery Study.

BackgroundIncreased blood and plasma viscosity, hematocrit, fibrinogen, and activation of coagulation and leukocytes have been reported in patients with claudication; however, their associations with symptomatic and asymptomatic peripheral arterial disease have not been reported in an epidemiological study Methods and ResultsBlood and plasma viscosity, hematocrit, fibrinogen, urinary fibrinopeptide A, plasma leukocyte elastase, and uric acid were measured in a random sample of 1,581 men and women aged 55-74 years in Edinburgh, Scotland, and related to peripheral arterial stenosis (ankle-brachial systolic pressure index, ABPI) and to lower limb ischemia (intermittent claudication and reactive hyperemia test). Each variable (except fibrinopeptide A) was significantly related to prevalent symptomatic and asymptomatic peripheral arterial disease. On multivariate analysis, blood viscosity (p<0.05) and fibrinogen (p<0.01) were independently associated with peripheral arterial narrowing (ABPI); a positive interaction was found between fibrinogen and smoking in the association with ABPI. Plasma viscosity was associated with claudication in the presence of a given degree of arterial narrowing (odds ratio of claudication in top quintile compared with bottom quintile of plasma viscosity, 3.35; 95% CI, 1.32, 8.51). Leukocyte elastase and uric acid were each associated with reactive hyperemia independently of arterial narrowing (p<0.01). ConclusionBlood rheological factors and leukocyte activation as well as arterial narrowing are associated with lower limb ischemia in the general population and may be implicated in its pathogenesis.

Increasing incidence of aortic aneurysms in England and Wales.

The numbers of patients being admitted to hospital with aortic aneurysms have increased recently. A study was carried out to try to find out whether this was a true increase in incidence or whether it could be attributable to more accurate diagnosis and better surgical techniques. From analyses of routine statistics it was found that from 1950 to 1984 age standardised mortality rose 20-fold in men to 47.1 per 100,000 population and 11-fold in women to 22.2 per 100,000 and that this was mainly due to more deaths from abdominal aneurysms. Hospital admissions of men with abdominal aneurysms were found to have increased steadily from 1968 to 1983, but the increase for women admitted did not begin until 1978. An increase in both emergency and elective admissions and only a marginal fall in deaths in hospital (from 45% to 39%) suggest that admissions for abdominal aneurysms increased across a wide range of severity of disease. It is concluded for the following reasons that the true incidence of aortic aneurysms, particularly abdominal aneurysms, has been increasing in England and Wales: the trends are not wholly compatible with advances in diagnosis and surgery, there are inconsistencies by age and sex, and increases have occurred in the number of complicated as well as uncomplicated cases.

Quality of life following lower limb amputation for peripheral arterial disease

Lower limb amputations for peripheral arterial disease are performed predominantly on an elderly population with poor social support and concomitant medical problems. The effect of amputations on the quality of life of this population has not been properly assessed. The quality of life of 149 amputees from one hospital was evaluated using the Nottingham Health Profile and compared to that of a control group matched for age and sex. One hundred and thirty (87%) amputees and 115 (77%) controls responded to the questionnaire. Amputees reported significantly more problems with mobility, social isolation, lethargy, pain, sleep and emotional disturbance than controls (p < 0.001). However, mobility was the only significant independent factor after matched logistic regression analysis (p < 0.001). The differences in social isolation and emotional distress lost their significance after adjustment for mobility. The overall quality of life following lower limb amputation for peripheral arterial disease is poor, but much of this is secondary to restricted mobility. Rehabilitation following amputation should therefore focus on attempts to improve mobility.

Cross-linked fibrin degradation products, progression of peripheral arterial disease, and risk of coronary heart disease

Haemostatic and rheological factors may predict cardiovascular disease. We studied patients with intermittent claudication to see if the progression of peripheral arterial disease and the risks of coronary events could be predicted by baseline packed cell volume, plasma fibrinogen, blood and plasma viscosites, von Willebrand factor antigen, cross-linked fibrin degradation products (XLFDP), urinary fibrinopeptide A, and plasma leucocyte elastase. In 617 patients with claudication followed up for one year, baseline XLFDP was related most strongly to coronary events, relative risk 4.4 (95% CI 1.3-19.0) between top and bottom quintiles. Plasma fibrinogen was the strongest independent predictor of death from coronary disease. XLFDP was the only factor, in addition to age and cigarette smoking, that was independently associated (p = 0.008) with deterioration in peripheral arterial disease. We conclude that, in patients with peripheral arterial disease, plasma concentration of XLFDP, a measure of ongoing fibrin formation and degradation, is a strong predictor of both disease progression and future coronary risk. These results accord with the hypothesis that fibrin formation contributes to progression of coronary and peripheral atherosclerosis.

Improved Prediction of Fatal Myocardial Infarction Using the Ankle Brachial Index in Addition to Conventional Risk Factors The Edinburgh Artery Study

Background—Prediction of major cardiovascular and cerebrovascular events using conventional risk factor models is limited. Noninvasive measures of subclinical atherosclerosis such as the ankle brachial index (ABI) could improve risk prediction and provide more focused primary prevention strategies. We wished to determine the added value of a low ABI in the prediction of long-term risk of cardiovascular and cerebrovascular events and death. Methods and Results—In 1988, 1592 men and women 55 to 74 years of age were randomly selected from the age-sex registers of 11 general practices in Edinburgh, Scotland, and followed up over a period of 12 years for incident events. After adjustment for age and sex, an ABI ≤0.9 was predictive of an increased risk of fatal myocardial infarction (MI), cardiovascular death, all-cause death, combined fatal and nonfatal MI, and total cardiovascular events. After further adjustment for prevalent cardiovascular disease, diabetes, and conventional risk factors, a low ABI was independently predictive of the risk of fatal MI. Addition of the ABI significantly (P≤0.01) increased the predictive value of the model for fatal MI compared with a model containing risk factors alone. Comparison of areas under receiver operator characteristic curves confirmed that a model including the ABI discriminated marginally better than one without. Conclusions—Addition of the ABI significantly improved prediction of fatal MI over and above that of conventional risk factors. We recommend that the ABI be incorporated into routine cardiovascular screening and that the potential of its inclusion into cardiovascular scoring systems (with a view to improving their accuracy) now be examined.

Fibrinogen genotype and risk of peripheral atherosclerosis

There is conflicting evidence about the influence of fibrinogen genotype on plasma fibrinogen concentrations, and the relation between genotype and atherosclerotic disease has not been studied. In a population-based case-control study we aimed to find out whether certain fibrinogen genotypes are associated with an increased risk of peripheral atherosclerosis. 121 subjects with peripheral arterial disease and 126 healthy controls matched for age and sex were selected from a random population sample aged 55-74 years in the Edinburgh Artery Study. Mean fibrinogen concentrations were higher in cases than in controls (3.12 [95% confidence interval 2.99-3.26] vs 2.75 [2.64-2.85], p less than 0.001). A greater proportion of cases than controls were homozygous or heterozygous for an allele at the beta fibrinogen locus (4.2 kb allele, Bcl I digestion); the allele frequency was 0.197 in cases and 0.097 in controls (p less than 0.005). Extended haplotypes for 4.2 kb heterozygotes were also associated with an increased risk of peripheral arterial disease. However, haplotype had only a small effect on the association of plasma fibrinogen concentration with disease, and the relation of haplotype with disease was independent of age, sex, social class, smoking status, plasma fibrinogen, alcohol consumption, body mass index, and diabetes mellitus. We conclude that variation at the beta fibrinogen locus is associated with an increased risk of peripheral atherosclerosis. The influence is not mediated simply by way of increased fibrinogen concentrations but could be due to a structurally variant fibrinogen or linkage disequilibrium with a neighbouring gene.

Relationships between ability and personality:does intelligence contribute positively to personal and social adjustment?

Intelligence/personality associations were studied in four large datasets. Correlations between general ability (g) and major personality traits were generally consistent with previous findings. For other traits, an interpretation of the correlation patterning is that traits classifiable as adaptive in terms of personal and social adjustment have positive correlations with g, whilst maladaptive traits have negative correlations. Regression modelling confirmed these associations and structural equation modelling of selected traits showed that Neuroticism acts as a mediator of g on the outcome. Non-linear relationships between intelligence and personality were not found. In two of the datasets the correlation between Neuroticism and Psychoticism decreased with ability level, and the correlation between fluid and crystallised ability increased with level of Neuroticism.

Smoking, haemostatic factors and lipid peroxides in a population case control study of peripheral arterial disease

The aim of this study was to determine differences between cases of peripheral arterial disease and healthy controls in levels of haemostatic factors and lipid peroxides and the influence of cigarette smoking. The study groups were selected from the Edinburgh Artery Study which is a random sample survey of men and women aged 55-74 years. Mean levels of plasma fibrinogen, von Willebrand factor, beta-thromboglobulin, plasminogen activator inhibitor (type I), cross-linked fibrin degradation products and lipid peroxides were markedly elevated in 121 study cases compared with 126 age- and sex-matched controls. For example, cross-linked fibrin degradation products had a geometric mean of 106.8 ng/ml (95% confidence interval (CI) 95.3, 119.8) in study cases and 74.7 ng/ml (95% CI 67.0, 83.4) in controls (P < 0.001). Inclusion of smoking in logistic regressions of each factor on peripheral arterial disease significantly reduced the odds of disease for von Willebrand factor and for cross-linked fibrin degradation products, but had little effect on the increased odds associated with fibrinogen, beta-thromboglobulin, plasminogen activator inhibitor and lipid peroxides. We conclude that, in men and women in Edinburgh, peripheral atherosclerosis is associated with lipid peroxidation, endothelial disturbance, platelet activation, elevated fibrinogen, fibrin formation and increased inhibition of fibrinolysis. The most important effects of cigarette smoking in promoting atherosclerosis may be endothelial disturbance and fibrin formation.

Plasma fibrinogen, haemostatic factors and prediction of peripheral arterial disease in the Edinburgh Artery Study.

&NA; The role of fibrinogen and other haemostatic factors in prediction of peripheral arterial disease (PAD) has not been established. We examined the associations of plasma fibrinogen, von Willebrand Factor (vWF), tissue plasminogen activator (t‐PA) antigen, fibrin D‐dimer, and factor VII with the development and clinical progression of PAD. In the Edinburgh Artery Study, 1592 men and women, aged between 55 and 74 years, were followed prospectively over 5 years to detect the onset of PAD, and the deterioration of established PAD. At baseline, 418 individuals had evidence of PAD and 60 (14.4%) subsequently deteriorated. 1080 subjects had no baseline disease, but 59 (5.5%) developed PAD during follow‐up. Median levels of fibrinogen and vWF were higher in the group developing disease compared with the group which did not (2.78 g/l versus 2.57 g/l, P ≤ 0.01; 116 IU/dl versus 104 IU/dl, P ≤ 0.05; respectively). After adjusting for age and sex, fibrinogen (P ≤ 0.01) and vWF (P ≤ 0.05) were significantly associated with the risk of developing PAD. The association between fibrinogen and development of disease remained after adjusting for cardiovascular risk factors and baseline ischaemic heart disease (relative risk, 1.35, 95% confidence interval, 1.05, 1.73; P ≤ 0.05). None of the haemostatic factors were significantly associated with progression of PAD. In conclusion, plasma fibrinogen levels are related to the future onset of PAD, providing further evidence of a possible role of elevated fibrinogen in the development of atherosclerotic disease.