Prothrombin fragment 1+2 is associated with intima media thickness of the carotid artery in patients with myocardial infarction

Myocardial injury after non-cardiac surgery and per operative fibrin metabolism in patients undergoing hip-fracture surgery: an observational study

Myocardial injury after non-cardiac surgery (MINS) is associated with a 2-3-fold increased risk of subsequent major cardiovascular events and postoperative mortality. The pathological mechanism behind MINS is not fully uncovered. We hypothesized that patients with MINS following hip fracture surgery would have an altered haemostatic balance pre- and postoperative compared with patients without MINS. This was investigated in a prospective single-centre observational study including patients consecutively. The outcomes were changes in thrombin generation, fibrinogen/fibrin turnover, tissue plasminogen activator, plasminogen activator inhibitor-1 and fibrin structure measurements in patients developing MINS and patients who did not. Outcomes were measured preoperatively and two hours postoperatively. Seventy-two patients were included whereof 26 (36%) patients developed MINS. D-dimer delta values were significantly higher in patients developing MINS than in patients who did not (p = 0.01). After adjusting for age, sex, smoking, alcohol abuse, atrial fibrillation, anticoagulant medication preoperative CRP, preoperative creatinine and duration of surgery, the association remained significant (p = 0.04). There were no significant changes in thrombin generation, in markers of fibrinogen/fibrin turnover besides D-dimer, or in fibrin structure measurements pre- and postoperatively between patients with and without MINS. As such, a relationship between the coagulative and fibrinolytic activity and MINS cannot be ruled out in patients with MINS after hip fracture surgery. Registration: The study was an observational sub-study to a multicentre randomised clinical trial registered at ClinicalTrials.gov (NCT02344797).

Differential cellular effects of old and new oral anticoagulants: consequences to the genesis and progression of atherosclerosis

The main purpose of anticoagulants is to diminish fibrin formation, thereby decreasing the risk of venous or arterial thrombosis. Vitamin K antagonist have been used for many decades in order to achieve reduced thrombotic risk, despite major drawbacks of this class of drugs such as cumbersome dossing and monitoring of anticoagulant status. To overcome these drawbacks of VKA, new classes of anticoagulants have been developed including oral anticoagulants for direct inhibition of either thrombin or factor Xa, which can be administrated in a fixed dose without monitoring. Coagulation factors can activate cellular protease-activated receptors, thereby inducing cellular processes as inflammation, apoptosis, migration, and fibrosis. Therefore, inhibition of coagulation proteases not only attenuates fibrin formation, but may also influence pathophysiological processes like vascular calcification and atherosclerosis. Animal models revealed that VKA therapy induced both intima and media calcification and accelerated plaque vulnerability, whereas specific and direct inhibition of thrombin or factor Xa attenuated atherosclerosis. In this review we provide an overview of old and new oral anticoagulants, as well discuss potential pleiotropic effects with regard to calcification and atherosclerosis. Although translation from animal model to clinical patients seems difficult at first sight, effort should be made to fully understand the clinical implications of long-term oral anticoagulant therapy on vascular side effects.

Apolipoprotein polymorphism is associated with pro-thrombotic profile in non-demented dyslipidemic subjects

Apolipoprotein gene polymorphism has an important role in lipid metabolism and in the development of cerebro- and cardio-vascular disease (CCVD), including dementia. Dyslipidemia and hemostatic abnormalities are key risk factors associated with athero-sclerotic events preceding CCVD. The aim of this study was to evaluate the possible relationships of various apolipoprotein-species with hemostatic parameters and cognitive function. Lipid profile, gene polymorphism, coagulation markers, and mini-mental state examination (MMSE) scores were assessed in 109 dys-lipidemic subjects and in 107 healthy control volunteers. Thrombin-activatable fibrinolysis inhibitor (TAFI) plasma levels were significantly higher in apolipoprotein-E2 (apoE2) patients when compared to other apoE forms. The apoA5 -1131T>C polymorphism was associated with elevated D-dimer concentration in dyslipidemic TT homozygous individuals. MMSE did not correlate with lipid or coagulation profile. These data suggest that apoE and apoA5 variants have an effect on hemostatic parameters, but they neither influence nor predict cognitive performance in non-demented individuals.

Individuals with coronary artery disease at a young age and features of the metabolic syndrome have an increased prothrombotic potential

The relation between coagulation and atherosclerosis has been extensively described, pointing towards a hypercoagulable state in patients with atherosclerosis, especially in young individuals. However, not all studies were conclusive. It is known that the metabolic syndrome (MetS), a risk factor for coronary artery disease (CAD), is related to a higher incidence of thrombo-embolic events. We hypothesised that individuals with CAD at a young age and MetS have an increased prothrombotic potential. It was the study objective to analyse the endogenous thrombin potential (ETP) and related thrombin generation parameters in patients with CAD before the age of 51 in men and 56 in women with and without MetS features and their healthy first-degree relatives. In this case-control study we included 118 CAD patients and 50 first-degree relatives (controls). Parameters of thrombin generation were obtained with calibrated automated thrombinography. An adjusted general linear model (GLM) showed a positive association between the peak thrombin levels and the presence of CAD at a young age. Based on the NCEP criteria we divided our patient group in CAD patients with and without MetS, and compared them to the controls without MetS. We showed that CAD patients with MetS have increased ETP levels, both in comparison with healthy first-degree relatives and with CAD patients without MetS. There were no differences in ETP between patients without MetS and healthy controls. In conclusion, this study shows that individuals with CAD at a young age and MetS features have an increased prothrombotic potential, compared to CAD patients without MetS.

Accelerated in vivo thrombin formation independently predicts the presence and severity of CT angiographic coronary atherosclerosis

OBJECTIVES

This study sought to investigate the association between thrombin generation in plasma and the presence and severity of computed tomography angiographically defined coronary atherosclerosis in patients with suspected coronary artery disease (CAD).

BACKGROUND

Besides its pivotal role in thrombus formation, experimental data indicate that thrombin can induce an array of pro-atherogenic and plaque-destabilizing effects. Although thrombin plays a role in the pathophysiology of atherosclerosis progression and vascular calcification, the clinical evidence remains limited.

METHODS

Using 64-slice coronary computed tomographic angiography, we assessed the presence and characteristics of CAD in patients (n = 295; median age 58 years) with stable chest pain. Coronary artery calcification was graded as absent (Agatston score 0), mild (Agatston score 1 to 100), moderate (Agatston score 101 to 400), and severe (Agatston score >400). Calibrated automated thrombography was used to assess endogenous thrombin potential in plasma in vitro. Thrombin-antithrombin complex (TATc) levels were measured as a marker for thrombin formation in vivo.

RESULTS

TATc plasma levels were substantially higher in patients with CAD versus patients without CAD (p = 0.004). Significant positive correlations were observed between steadily increasing TATc levels and the severity of CAD (r = 0.225, p < 0.001). In multinomial logistic regression models, after adjusting for established risk factors, TATc levels predicted the degree of coronary artery calcification: mild (odds ratio: 1.56, p = 0.006), moderate (odds ratio: 1.56, p = 0.007), and severe (odds ratio: 1.67, p = 0.002). Trends were comparable between the groups when stratified according to the degree of coronary luminal stenosis.

CONCLUSIONS

This study provides novel clinical evidence indicating a positive independent association between enhanced in vivo thrombin generation and the presence and severity of coronary atherosclerosis, which may suggest that thrombin plays a role in the pathophysiology of vascular calcification and atherosclerosis progression.

The impact of blood coagulability on atherosclerosis and cardiovascular disease

Although the link between blood coagulation and atherogenesis has been long postulated, only recently, and through the extensive work on transgenic mice, crossbred on an atherogenic background, has the direction of this interaction become visible. In general, hypercoagulability in mice tends to increase atherosclerosis, whereas hypocoagulability reduces the atherosclerotic burden, depending on the mouse model used. The information on a direct relationship between coagulation and atherosclerosis in humans, however, is not that clear. Almost all coagulation proteins, including tissue factor, are found in atherosclerotic lesions in humans. In addition to producing local fibrin, a matrix for cell growth, serine proteases such as thrombin may be very important in cell signaling processes, acting through the activation of protease-activated receptors (PARs). Activation of PARs on vascular cells drives many complex processes involved in the development and progression of atherosclerosis, including inflammation, angiogenesis, and cell proliferation. Although current imaging techniques do not allow for a detailed analysis of atherosclerotic lesion phenotype, hypercoagulability, defined either by gene defects of coagulation proteins or elevated levels of circulating markers of activated coagulation, has been linked to atherosclerosis-related ischemic arterial disease. New, high-resolution imaging techniques and sensitive markers of activated coagulation are needed in order to study a causal contribution of hypercoagulability to the pathophysiology of atherosclerosis. Novel selective inhibitors of coagulation enzymes potentially have vascular effects, including inhibition of atherogenesis through attenuation of inflammatory pathways. Therefore, we propose that studying the long-term vascular side effects of this novel class of oral anticoagulants should become a clinical research priority.

Echogenicity of the carotid intima-media complex and cardiovascular risk factors

INTRODUCTION

Increased carotid intima-media thickness (IMT) has been associated with increased risk of myocardial infarction (MI) and stroke. A measure of echogenicity, the grey scale median (GSM), has been shown to be inversely correlated with cardiovascular risk factors and to be predictive of mortality in a community-based cohort. We assessed the factors associated with carotid IM-GSM in younger, non-diabetic patients with a recent MI.

METHODS AND RESULTS

A total of 122 patients (women, 25%) aged 31-80 years (61) were recruited 2-3 days after an acute MI. Ultrasound examinations of the carotid arteries were performed 1-12 months after the MI. IMT was 0·78 (SD 0·17) mm on the right side and 0·81 (0·20) mm on the left side (P = 0·05). GSM was 88·60 (range 46-132, SD 18·32) on the right side and 82·10 (40-126, 17·89) on the left side (P = 0·002). Triglycerides (TG) correlated with GSM on both sides (right, r = -0·27, P = 0·003; left, r = -0·18, P = 0·05). On the right side, GSM was 92·15 and 82·26 (P = 0·05) in patients with TG < and ≥1·7, and on the left side, it was 84·04 and 74·55 (P = 0·02) in patients with TG < and ≥2·3. On multivariate analysis, TG were significantly associated with GSM, both on the right side (P = 0·01) and on the left side (P = 0·009).

CONCLUSION

We found a negative association between TG and carotid IM-GSM on both sides in patients with a recent MI. Our results also suggest that atherosclerosis progression may be faster on the left side in patients with coronary heart disease.