Clopidogrel plus aspirin versus aspirin alone for preventing cardiovascular disease.

BACKGROUND: Aspirin is the prophylactic antiplatelet drug of choice for people with cardiovascular disease. Adding a second antiplatelet drug to aspirin may produce additional benefit for those at high risk and those with established cardiovascular disease. OBJECTIVES: To quantify the benefit and harm of adding clopidogrel to standard long-term aspirin therapy for preventing cardiovascular events in people at high risk of cardiovascular disease and those with established cardiovascular disease. SEARCH STRATEGY: The searches have been updated: CENTRAL (Issue 3 2009), MEDLINE (2002 to September 2009) and EMBASE (2002 to September 2009). SELECTION CRITERIA: All randomized controlled trials comparing long term use of aspirin plus clopidogrel with aspirin plus placebo or aspirin alone in patients with coronary disease, ischemic cerebrovascular disease, peripheral arterial disease, or at high risk of atherothrombotic disease were included. DATA COLLECTION AND ANALYSIS: Data on mortality, non-fatal myocardial infarction, non-fatal stroke, unstable angina, heart failure, revascularizations, major and minor bleeding, and all adverse events were collected. The overall treatment effect was estimated by the pooled odds ratio (OR) with 95% confidence interval (CI) using a fixed-effect model (Mantel-Haenszel). MAIN RESULTS: No new studies were identified from the updated searches. A total of two RCTs were found: the CHARISMA and the CURE study. The CURE study enrolled only patients with a recent non-ST segment elevation acute coronary syndrome. The use of clopidogrel plus aspirin, compared with placebo plus aspirin, was associated with a lower risk of cardiovascular events (OR: 0.87, 95% CI 0.81 to 0.94; P<0.01) and a higher risk of major bleeding (OR 1.34, 95% CI 1.14 to 1.57; P<0.01). Overall, we would expect 13 cardiovascular events to be prevented for every 1000 patients treated with the combination, but 6 major bleeds would be caused. In the CURE trial, for every 1000 people treated, 23 events would be avoided and 10 major bleeds would be caused. In the CHARISMA trial, for every 1000 people treated, 5 cardiovascular events would be avoided and 3 major bleeds would be caused. AUTHORS' CONCLUSIONS: The available evidence demonstrates that the use of clopidogrel plus aspirin is associated with a reduction in the risk of cardiovascular events and an increased risk of bleeding compared with aspirin alone. Only in patients with acute non-ST coronary syndrome benefits outweigh harms.

Influenza vaccines for preventing coronary heart disease.

BACKGROUND: Vaccination against influenza may reduce the risk of coronary heart disease. However the evidence is scarce and the size of the benefit is unknown. OBJECTIVES: To assess the potential benefit of influenza vaccination for primary and secondary prevention of coronary heart disease. SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials, Issue 4 2007, MEDLINE (2005 to January 2008) and EMBASE (2005 to January 2008). Furthermore, we searched databases for recent or ongoing trials and reference lists of articles. Lastly, we contacted pharmaceutical companies for non published data or trials on influenza vaccination. No language restrictions were applied. SELECTION CRITERIA: Randomised clinical trials of influenza vaccination compared to placebo or no treatment in primary or secondary prevention with outcome on coronary heart disease. DATA COLLECTION AND ANALYSIS: Data extraction and the assessment of quality was done with a predefined form by two review authors independently. We contacted investigators when data on the outcome were missing. MAIN RESULTS: In the two included trials, 778 participants were randomised to vaccination or placebo. Only 39 participants died a cardiovascular death. In addition, only 35 participants had an acute myocardial infarction. Consequently, estimates of treatment effects were imprecise. AUTHORS' CONCLUSIONS: Despite the significant effect noted in the studies, we concluded that there are not enough data to evaluate the effect of vaccination on coronary heart disease.

Selective expansion of influenza A virus-specific T cells in symptomatic human carotid artery atherosclerotic plaques.

BACKGROUND AND PURPOSE: Evidence is accumulating that infection with influenza A virus contributes to atherothrombotic disease. Vaccination against influenza decreases the risk of atherosclerotic syndromes, indicating that inflammatory mechanisms may be involved. We tested the hypothesis that influenza A virus-specific T cells contribute to atherosclerotic plaque inflammation, which mediates the onset of plaque rupture. METHODS: T-cell cultures were generated from atherosclerotic segments and peripheral blood of 30 patients with symptomatic carotid artery disease. The response of plaque and peripheral blood T cells to influenza A virus was analyzed and expressed as a stimulation index (SI). Selective outgrowth of intraplaque influenza A-specific T cells was calculated by the ratio of plaque T cell SI and peripheral blood T cell SI for each patient. Accordingly, the patients were categorized as high- (SI ratio >or=5), intermediate- (5

Influenza infection and risk of acute pulmonary embolism.

BACKGROUND: Influenza infections have been associated with procoagulant changes. Whether influenza infections lead to an increased risk of pulmonary embolism remains to be established. METHODS: We conducted a nested case control study in a large cohort of patients with a clinical suspicion of having pulmonary embolism. Blood samples were collected to investigate the presence of influenza A and B by complement fixation assay (CFA). We compared case patients, in whom pulmonary embolism was proven (n = 102), to controls, in whom pulmonary embolism was excluded (n = 395). Furthermore, we compared symptoms of influenza-like illness in both patient groups 2 weeks prior to inclusion in the study, using the influenza-like illness (ILI) score, which is based on a questionnaire. We calculated the risk of pulmonary embolism associated with influenza infection. RESULTS: The percentage of patients with influenza A was higher in the control group compared to the case group (4.3% versus 1.0%, respectively, odds ratio 0.22; 95% CI: 0.03-1.72). Influenza B was not detectable in any of the cases and was found in 3 of the 395 controls (0.8%). The ILI score was positive in 24% of the cases and 25% in the control persons (odds ratio 1.16, 95% CI: 0.67-2.01). We did not observe an association between the ILI score and proven influenza infection. CONCLUSION: In this clinical study, influenza infection was not associated with an increased risk of acute pulmonary embolism. The ILI score is non-specific in this clinical setting.

Effects on coagulation and fibrinolysis induced by influenza in mice with a reduced capacity to generate activated protein C and a deficiency in plasminogen activator inhibitor type 1.

Influenza infections increase the risk of diseases associated with a prothrombotic state, such as venous thrombosis and atherothrombotic diseases. However, it is unclear whether influenza leads to a prothrombotic state in vivo. To determine whether influenza activates coagulation, we measured coagulation and fibrinolysis in influenza-infected C57BL/6 mice. We found that influenza increased thrombin generation, fibrin deposition, and fibrinolysis. In addition, we used various anti- and prothrombotic models to study pathways involved in the influenza-induced prothrombotic state. A reduced capacity to generate activated protein C in TM(pro/pro) mice increased thrombin generation and fibrinolysis, whereas treatment with heparin decreased thrombin generation in influenza-infected C57Bl/6 mice. Thrombin generation was not changed in hyperfibrinolytic mice, deficient in plasminogen activator inhibitor type-1 (PAI-1(-/-)); however, increased fibrin degradation was seen. Treatment with tranexamic acid reduced fibrinolysis, but thrombin generation was unchanged. We conclude that influenza infection generates thrombin, increased by reduced levels of protein C and decreased by heparin. The fibrinolytic system appears not to be important for thrombin generation. These findings suggest that influenza leads to a prothrombotic state by coagulation activation. Heparin treatment reduces the influenza induced prothrombotic state.

Serum levels of mannose-binding lectin and the risk of future coronary artery disease in apparently healthy men and women.

OBJECTIVE: To determine the association between serum levels of mannose-binding lectin (MBL) and the risk of future coronary artery disease (CAD) in apparently healthy men and women. METHODS AND RESULTS: We performed a prospective case-control study among apparently healthy men and women nested in the EPIC-Norfolk cohort. Baseline concentrations of MBL were measured in serum samples of 946 patients who experienced a myocardial infarction or died of CAD during follow-up, and 1799 matched controls who remained free of CAD. Among men, median MBL levels were 1.63 ng/mL (interquartile range [IQR]: 0.59 to 3.80) in cases and 1.20 ng/mL (IQR: 0.48 to 3.37) in controls. Among women, median MBL levels were 1.02 ng/mL (IQR: 0.43 to 2.95) in cases and 1.01 ng/mL (IQR: 0.43 to 2.94) in controls. After adjustment, the odds ratio in men for future CAD was 1.59 (95% confidence interval [CI]: 1.09 to 2.32; P for linearity=0.01) for those in the highest quartile compared with those in the lowest quartile. In women no such relation was observed. CONCLUSIONS: Elevated levels of MBL are associated with an increased risk of future CAD in apparently healthy men but not in women. The sex difference merits further exploration.

Serum levels of type II secretory phospholipase A2 and the risk of future coronary artery disease in apparently healthy men and women: the EPIC-Norfolk Prospective Population Study.

OBJECTIVES: To study the prospective relationship between serum levels of type II secretory phospholipase A2 (sPLA2) and the risk of future coronary artery disease (CAD) in apparently healthy men and women. METHODS AND RESULTS: We conducted a prospective nested case-control study among apparently healthy men and women aged 45 to 79 years. Cases (n=1105) were people in whom fatal or nonfatal CAD developed during follow-up. Controls (n=2209) were matched by age, sex, and enrollment time. sPLA2 levels were significantly higher in cases than controls (9.5 ng/mL; interquartile range [IQR], 6.4 to 14.8 versus 8.3 ng/mL; IQR, 5.8 to 12.6; P<0.0001). sPLA2 plasma levels significantly correlated with age, body mass index, systolic blood pressure, high-density lipoprotein (HDL) cholesterol levels, and C-reactive protein (CRP) levels. Taking into account matching for sex and age and adjusting for body mass index, smoking, diabetes, systolic blood pressure, low-density lipoprotein cholesterol, HDL cholesterol, and CRP levels, the risk of future CAD was 1.34 (1.02 to 1.71; P=0.02) for people in the highest sPLA2 quartile, compared with those in the lowest (P for linearity=0.03). CONCLUSIONS: Elevated levels of sPLA2 were associated with an increased risk of future CAD in apparently healthy individuals. The magnitude of the association was similar to that observed between CRP and CAD risk, and both associations were independent.

Chlamydia pneumoniae infections in mouse models: relevance for atherosclerosis research.

Mouse models have been frequently used in the study of Chlamydia pneumoniae (also known as Chlamydophila pneumoniae) infections. This gram-negative obligate intracellular bacterium causes respiratory infections, followed by dissemination of the bacterium to various organs throughout the body, including cardiovascular tissues, supporting the current hypothesis of a relationship between C. pneumoniae and atherosclerosis. Recently, clinical trials evaluated the effect of antichlamydial antibiotics on secondary cardiovascular events. Although small studies showed some effect, the large WIZARD study did not confirm these results, and the role of antichlamydial antibiotics in prevention of secondary events was questioned. To address these issues, data obtained from mouse models were systematically reviewed here. C. pneumoniae infections showed atherogenic properties in mice that were reproducible and confirmed by different research groups. However, antibiotic therapy was of limited value in these mouse models. Antibiotic therapy effectively cleared the acute infection, but did not influence the atherogenic properties of C. pneumoniae unless the therapy was started early during the acute infection. The results summarized here may help to better understand the results of the clinical antibiotic trials.

Infection and inflammation and the coagulation system.

Severe infection and inflammation almost invariably lead to hemostatic abnormalities, ranging from insignificant laboratory changes to severe disseminated intravascular coagulation (DIC). Systemic inflammation results in activation of coagulation, due to tissue factor-mediated thrombin generation, downregulation of physiological anticoagulant mechanisms, and inhibition of fibrinolysis. Pro-inflammatory cytokines play a central role in the differential effects on the coagulation and fibrinolysis pathways. Vice-versa, activation of the coagulation system may importantly affect inflammatory responses by direct and indirect mechanisms. Apart from the general coagulation response to inflammation associated with severe infection, specific infections may cause distinct features, such as hemorrhagic fever or thrombotic microangiopathy. The relevance of the cross-talk between inflammation and coagulation is underlined by the promising results in the treatment of severe systemic infection with modulators of coagulation and inflammation.

Infections and endothelial cells.

Systemic infection by various pathogens interacts with the endothelium and may result in altered coagulation, vasculitis and atherosclerosis. Endothelium plays a role in the initiation and regulation of both coagulation and fibrinolysis. Exposure of endothelial cells may lead to rapid activation of coagulation via tissue factor (TF) expression and the loss of anticoagulant properties by impairment of antithrombin III, TF pathway inhibitor (TFPI) and the protein C system. Endothelial-derived plasminogen activator inhibitor (PAI) is essential for the regulation of fibrinolysis and impaired endothelial function leads to imbalance in fibrinolysis, resulting in a procoagulant state. The interaction between inflammation and coagulation, soluble adhesion molecules and circulation endothelial cells is important in the pathogenesis of an unbalanced haemostatic system. Rather than being a unidirectional relationship, the interaction between inflammation and coagulation appears to be significant. In the crosstalk, the endothelium is playing a pivotal role.

Effect of recombinant activated factor VII on perioperative blood loss in patients undergoing retropubic prostatectomy: a double-blind placebo-controlled randomised trial.

BACKGROUND: Recombinant activated factor VII (factor VIIa) has prohaemostatic effects in bleeding patients with coagulation abnormalities. We aimed to test the hypothesis that recombinant factor VIIa could reduce perioperative blood loss in patients with normal coagulation systems. Therefore, we assessed safety and efficacy of this drug in patients undergoing retropubic prostatectomy, which is often associated with major blood loss and need for transfusion. METHODS: In a double-blind, randomised placebo-controlled trial, we recorded blood loss and transfusion requirements in 36 patients undergoing retropubic prostatectomy, who were randomised to receive an intravenous bolus of recombinant factor VIIa (20 microg/kg or 40 microg/kg) or placebo in the early operative phase. FINDINGS: Median perioperative blood loss was 1235 mL (IQR 1025-1407) and 1089 mL (928-1320) in groups given recombinant factor VIIa 20 microg/kg and 40 microg/kg, respectively, compared with 2688 mL (1707-3565) in the placebo group (p=0.001). Seven of twelve placebo-treated patients were transfused, whereas no patients who received 40 microg/kg recombinant factor VIIa needed transfusion. The odds ratio for receiving any blood product in patients treated with recombinant factor VIIa compared with control patients was 0 (95% CI 0.00-0.33) No adverse events arose. INTERPRETATION: An injection of recombinant factor VIIa can reduce perioperative blood loss and eliminate the need for transfusion in patients undergoing major surgery.