Dimitrios N. Tziakas

A randomized trial of genotype-guided dosing of acenocoumarol and phenprocoumon.

BACKGROUND Observational evidence suggests that the use of a genotype-guided dosing algorithm may increase the effectiveness and safety of acenocoumarol and phenprocoumon therapy. METHODS We conducted two single-blind, randomized trials comparing a genotype-guided dosing algorithm that included clinical variables and genotyping for CYP2C9 and VKORC1 with a dosing algorithm that included only clinical variables, for the initiation of acenocoumarol or phenprocoumon treatment in patients with atrial fibrillation or venous thromboembolism. The primary outcome was the percentage of time in the target range for the international normalized ratio (INR; target range, 2.0 to 3.0) in the 12-week period after the initiation of therapy. Owing to low enrollment, the two trials were combined for analysis. The primary outcome was assessed in patients who remained in the trial for at least 10 weeks. RESULTS A total of 548 patients were enrolled (273 patients in the genotype-guided group and 275 in the control group). The follow-up was at least 10 weeks for 239 patients in the genotype-guided group and 245 in the control group. The percentage of time in the therapeutic INR range was 61.6% for patients receiving genotype-guided dosing and 60.2% for those receiving clinically guided dosing (P=0.52). There were no significant differences between the two groups for several secondary outcomes. The percentage of time in the therapeutic range during the first 4 weeks after the initiation of treatment in the two groups was 52.8% and 47.5% (P=0.02), respectively. There were no significant differences with respect to the incidence of bleeding or thromboembolic events. CONCLUSIONS Genotype-guided dosing of acenocoumarol or phenprocoumon did not improve the percentage of time in the therapeutic INR range during the 12 weeks after the initiation of therapy. (Funded by the European Commission Seventh Framework Programme and others; EU-PACT ClinicalTrials.gov numbers, NCT01119261 and NCT01119274.).

Atrial Fibrillation and Hypercoagulability: Dependent on Clinical Factors or/and on Genetic Alterations?

AbstractIt is well known that atrial fibrillation is associated with high incidence of thromboembolic events, propably due to a prothrombotic or hypercoagulable state. However, it is unclear whether or not there is any difference of this prothrombotic state in the clinical subgroups of atrial fibrillation patients, that is, in those with paroxysmal, persistent or permanent atrial fibrillation. From the other side the role of the arrhythmia duration on the changes of coagulative variables in atrial fibrillation patients is not clearly enough.The contribution of genetic and functional alterations in factors of the coagulation and fibrinolytic pathways (that is hemostatic risk factors) to the development of hypercoagulation state in atrial fibrillation requires clarification.We investigated therefore (1) if there are differences in the prothrombotic state between patients with different clinical status of the arrhythmia, (2) if the arrhythmia duration per se could be an independent determinant of the prothrombotic state in all atrial fibrillation patients and (3) if coexistent genetic alterations in haemostatic risk factors in patients with atrial fibrillation could contribute to the development of prothrombotic abnormalities. Methods: Over a period of 23 months, we studied 55 patients with chronic non-valvular atrial fibrillation. We recruited 18 consecutive patients (13 men, mean age 59 ± 10 years) with paroxysmal atrial fibrillation 17 patients (11 men, mean age 61 ± 7 years) with persistent atrial fibrillation who underwent elective successful DC and remained in sinus rhythm at the 3 month visit and 20 patients (14 men mean age 64 ± 9) with permanent atrial fibrillation. Blood results were compared to 17 age-sex- and race-matched controls. The prothrombotic state was quantified by measurement of plasma levels of fibrinogen, soluble P-selectin (an index of platelet activation) and von Willebrand factor (a marker of endothelial dysfunction). We assessed the frequencies of factor V Leiden and prothrombin variant G20210A to determine whether particular inherited haemostatic risk factors may have contribution to the development of prothrombotic state in atrial fibrillation patients. Results: Permanent atrial fibrillation was associated with significant raised levels of von Willebrand factor, fibrinogen levels and soluble P-selectin compared to matched controls (all p < 0.001) and matched patients with paroxysmal and permanent AF (all p ranged between <0.003 and <0.002). Patients with persistent atrial fibrillation had significantly elevated von Willebrand factor levels (p = 0.0064) and fibrinogen levels (p = 0.002), but not Soluble P-selectin (p = 0.509). when compared to controls. Patients with paroxysmal atrial fibrillation had significantly elevated levels of P-selectin (p = 0.005) and fibrinogen (p = 0.003), but not von Willebrand factor (p = .0.61) compared to controls. Stepwise multiple regression analyses demonstrated that the arrhythmia duration (approximately 3 years) was an independent predictor of abnormal von Willebrand factor, fibrinogen and soluble P-selectin levels. Restoration of sinus rhythm in paroxysmal atrial fibrillation subgroup and successful electrical cardioversion of patients with permanent fibrillation atrial fibrillation did not significantly alter levels of the affected factors.The frequency of factor V Leiden was 8.9 in all studied patients with atrial fibrillation, versus 2.4% in the control group (odds ratio {OR} 4.6 [95% confidence (CI) 1.4–17.5], p = 0.02). The frequency of the prothrombin variant G20210A was 6.4.% compared with control group 1.6% (OR 4.9 [95% confidence interval (CI) 1.2–2.9], p = 0.04).There was a trend towards an increased frequency of factor V Leiden and/or prothrombin variant G20210A in patients age <55 years and in patients living at a particular area of Thrace mountains. Conclusions: Our results showed that there were significant differences in the prothrombotic state when patients with paroxysmal, and persistent atrial fibrillation were compared to matched patients with permanent atrial fibrillation and controls in sinus rhythm.The duration of the arrhythmia (about 3 years) was an independent predictor of abnormal measured factors. We found for the first time that some genetic alterations in haemostatic risk factors could be coexist in atrial fibrillation patients and may be a contributor to the development of hypercoagulability in atrial fibrillation patients.

Development of an easily applicable risk score model for contrast-induced nephropathy prediction after percutaneous coronary intervention: A novel approach tailored to current practice

BACKGROUND Several risk factors for contrast-induced nephropathy (CIN) after percutaneous coronary intervention (PCI) have been identified. The cumulative effect of these risk factors on renal function has been assessed with the development of risk score models in a number of studies. However, concerns were raised that estimates of the risk attributable to individual factors may be unreliable. We sought to develop a simple risk score for developing CIN after PCI irrespective of use of prophylactic measures and also capturing the effect of pre-intervention medication and presence of various co-morbidities. METHODS Consecutive patients treated with elective or urgent PCI at our cardiac catheterization laboratory were enrolled (derivation cohort n = 488, validation cohort n = 200). CIN was defined as increase ≥ 25% and/or ≥ 0.5 mg/dl in serum creatinine at 48 h after PCI vs baseline. Multivariable logistic regression analysis was then performed to identify independent predictors of CIN (pre-existing renal disease, metformin use, history of previous PCI, peripheral arterial disease and ≥ 300 ml of contrast volume). RESULTS The incidence of CIN in the development cohort was 10.2% with a significant trend across increasing score values (p < 0.001). The model demonstrated good discriminating power (c-statistic 0.759) and excellent calibration (calibration slope 0.91). The model was validated internally by bootstrapping in 1000 samples (c-statistic 0.753) and in a cohort of 200 patients (c-statistic 0.864) demonstrating stable performance. CONCLUSIONS The proposed risk score is easily applicable and allows for practically simple risk assessment compared to other published scores while at the same time overcomes drawbacks of previous model designs.

Red blood cell distribution width: a strong prognostic marker in cardiovascular disease: is associated with cholesterol content of erythrocyte membrane.

OBJECTIVES Red blood cell distribution width (RDW), a measure of the variability in size of circulating erythrocytes, has recently been shown to be a strong predictor of adverse outcomes in patients with a great spectrum of cardiovascular disease. Recently, cholesterol content of erythrocytes membranes (CEM) has been associated with clinical instability in coronary artery disease whilst it has been linked with red blood cells (RBC) size and shape. Since the biological mechanisms underlying the association of higher RDW with cardiovascular mortality risk are currently unclear, we studied the association of CEM with RDW. METHODS 296 consecutive angina patients (236 men, mean age 69 ± 2 years) were prospectively assessed; 160 had chronic stable angina (CSA) and 136 had an acute coronary syndrome (ACS). RESULTS Patients presenting with ACS had increased CEM levels (121.6 μg/mg (40.1) vs 74.4 μg/mg (26.6), p < 0.001) as well as exhibited greater anisocytosis (13.9% (0.9) vs 13.3% (0.7), p < 0.001) compared to patients with CSA. Simple correlation analysis showed that CEM levels were positively associated with RDW values (r = 0.320, p < 0.001). Multivariable linear regression showed that CEM levels were associated with RDW values independently from possible confounders (inflammatory, nutritional renal or hematological). CONCLUSIONS Data from the present study showed an independent association between cholesterol content of erythrocyte membranes and anisocytosis. Increased CEM levels -a novel biomarker of clinical instability in CAD - may facilitate our understanding why RDW is associated with increased morbidity and mortality in cardiovascular disease.

Anti-inflammatory cytokine profile in acute coronary syndromes: behavior of interleukin-10 in association with serum metalloproteinases and proinflammatory cytokines

BACKGROUND The anti-inflammatory cytokine interleukin-10 (IL-10) downregulates the production of metalloproteinases (MMPs) and upregulates the production of their tissue inhibitors (TIMPs). The aim of this study was to assess the levels of IL-10 in patients with acute myocardial infarction (AMI) and unstable angina (UA), as well as to investigate the relationship of circulating IL-10 with the levels of MMPs (MMP-1, -2, -9), their tissue inhibitor (TIMP-1), pro-inflammatory cytokines (IL-6, tumor necrosis factor (TNF)-alpha) and serum lipids in the same patient population. METHODS Serum MMP-1, -2, -9, TIMP-1, IL-6, TNF-alpha and IL-10 were measured by ELISA assays in 23 patients with AMI and 20 patients with UA after their hospital admission, as well as in 16 healthy controls subjects. The lipid profile was assessed by measuring the serum levels of total cholesterol, HDL-cholesterol, LDL-cholesterol and triglycerides. RESULTS AMI patients exhibited significantly higher serum levels of IL-10 as compared with those of UA patients and healthy controls (both P=0.005). In contrast, there was no significant difference in IL-10 levels between UA patients and healthy controls. In AMI patients there was a statistically significant positive correlation of serum IL-10 with the levels of MMP-9 (rho=0.588, P=0.003), IL-6 (rho=0.502, P=0.015) and HDL-cholesterol (rho=0.697, P<0.001), as well as a significant negative correlation with the levels of triglycerides (rho=-0.417, P=0.048). CONCLUSIONS Our results suggest that UA is associated with low serum activity of IL-10, while a significant elevation of this anti-inflammatory cytokine accompanies the peripheral immune responses of AMI. This observation indicates that different patterns of inflammatory reactions are implicated in the pathophysiology of two clinical conditions.

The role of red blood cells in the progression and instability of atherosclerotic plaque

This review attempts to present a focused summary of selected areas of the rapidly growing knowledge regarding the red blood cells role in atherosclerotic plaque progression and instability. A summary of the characteristics of the erythrocyte membranes is provided, followed by a brief review of the in vitro and in vivo work that has helped clarify their role in atherosclerosis. Mechanisms by which erythrocytes enter the atherosclerotic plaque and contribute to its progression and instability are presented. Finally, some elements that may be clinically important regarding erythrocytes in coronary artery disease are discussed.

Interleukin-8 is increased in the membrane of circulating erythrocytes in patients with acute coronary syndrome

AIMS Studies have shown that erythrocyte membranes are present within necrotic cores in atherosclerotic plaques, and that circulating erythrocytes in patients with acute coronary syndrome (ACS) have increased total cholesterol content (CEM). Interleukin-8 (IL-8) binds to erythrocytes and during intraplaque haemorrhage it is released into the plaque and thus may contribute to inflammatory cascade and atherosclerotic plaque instability. The present study was undertaken to test the hypothesis that erythrocyte membrane IL-8 is elevated in patients with ACS compared with those with chronic stable angina (CSA). METHODS AND RESULTS Consecutive patients who presented with CSA (n = 120, 92 men, 62 +/- 9 years), ACS (n = 118, 90 men, 62 +/- 10 years) or with chest pain who had normal coronary arteries (n = 36, 26 men, 60 +/- 7 years), were studied prospectively. IL-8 concentrations in erythrocyte membranes (rIL-8) and in plasma (pIL-8), C-reactive protein (CRP) and CEM were measured. rIL-8 levels [mean +/- 1 SD (standard deviation)] were higher in ACS (102.9 +/- 70.1 pg/mL) compared with CSA (44.7 +/- 22.8 pg/mL) (P < 0.001). No difference in pIL-8 levels between the two coronary artery disease groups was observed (P = 0.280). Serum CRP levels were correlated with rIL-8 levels (r = 0.294, P < 0.001); no association was found between CRP and pIL-8 levels (r = 0.025, P = 0.706). Further, rIL-8 had an independent association with ACS, when CRP and CEM were taken into consideration. CONCLUSION This study shows for the first time that rIL-8 content was significantly higher in ACS, compared with CSA. These findings endorse results from our previous studies suggesting that erythrocytes may play an important role in the development of unstable atherosclerotic plaque.

Epidemiology of the diabetic heart.

Diabetes mellitus is a worldwide epidemic. Cardiovascular disease remains the major cause of morbidity and mortality in people with diabetes. Studies have suggested that increased risk of cardiovascular disease is not restricted to type II or type I diabetes mellitus, but extends to prediabetic stages such as impaired fasting glucose, impaired glucose tolerance, metabolic syndrome, and obesity. Insulin resistance, impaired fasting glucose, impaired glucose tolerance, and diabetes mellitus form a continuous sequence of risk for cardiovascular disease. Therefore, cardiovascular disease mortality and morbidity within the diabetes epidemic grow into vast proportions. Evidence also exists that diabetic patients have a high prevalence of heart failure or impaired diastolic and systolic cardiac function subsequent to the combination of coronary artery disease, hypertension, and diabetic cardiomyopathy. In view of the proportions of this new epidemic, prevention of diabetes and its prediabetic states is likely to be the most effective strategy to prevent serious cardiovascular events.

Associations Between Collagen Synthesis and Degradation and Aortic Function in Arterial Hypertension

BACKGROUND Studies have suggested that collagen accumulation in the aortic wall may contribute to the stiff aorta in arterial hypertension. However, data in human hypertension are limited. In this investigation, relations between markers of collagen metabolism and aortic function in patients with arterial hypertension were evaluated. METHODS We studied 72 hypertensive patients (age 53 +/- 5 years) and 27 age- and gender-matched normotensive individuals. Elastic properties of the aorta were assessed by aortic pulse wave velocity (carotid-to-femoral pulse wave velocity (PWVc-f)). Free amino-terminal propeptides of precollagen type I (PINP, reflecting collagen I synthesis), serum telopeptides of collagen type I (CITP, an index of collagen I degradation), free amino-terminal propeptides on precollagen type III (PIIINP, reflecting collagen III metabolism), prometalloproteinase-1 (proMMP-1), and tissue inhibitor of metalloproteinase-1 (TIMP-1) levels were determined by commercially available immunoassays. RESULTS Patients with arterial hypertension had greater PWVc-f (P = 0.01); and higher levels of PINP/CITP compared to control (P = 0.04). PWVc-f was significantly associated with PINP/CITP ratio (analysis of variance (ANOVA), P = 0.03). Hypertensive patients had significantly higher levels of proMMP-1/TIMP-1 (P = 0.04); PWVc-f was significantly associated with proMMP-1 (ANOVA, P = 0.03) and proMMP-1/TIMP-1 (ANOVA, P = 0.04). Associations between PWVc-f and proMMP-1 and between PWVc-f and PINP/CITP ratio remained significant after adjustment for PWVc-f confounders and antihypertensive treatment. CONCLUSIONS Alterations in collagen turnover that favor collagen type I synthesis; as well as proMMP-1 expression are related to increased aortic stiffness in treated hypertensive individuals without left ventricular (LV) hypertrophy.

Total Cholesterol Content of Erythrocyte Membranes and Coronary Atherosclerosis: An Intravascular Ultrasound Pilot Study

Background: Increasing evidence suggests that erythrocytes may participate in atherogenesis. We sought to investigate the relationship between total cholesterol content in erythrocyte membranes (CEM) and coronary atheroma burden in patients with coronary artery disease (CAD). Methods: We prospectively enrolled 28 participants: 11 patients with angiographically significant CAD and 17 controls. Intravascular ultrasound (IVUS) and 3-dimensional reconstruction of coronary arteries was performed in the patient subgroup. Results: Cholesterol content of erythrocyte membranes was higher in patients compared to controls (P < .01). Cholesterol content of erythrocyte membranes correlated with total atheroma volume (r = .82, P < .01) and with percentage plaque area at the vessel site with minimal lumen area (r = .75, P < .05). On multivariate analysis, CEM was the only variable independently predicting total atheroma volume (P = .05). Conclusions: This pilot study is the first to demonstrate a significant relation between CEM and coronary atherosclerotic burden, suggesting a possible role of erythrocyte membrane—derived lipids in the expansion of atheromata. The results merit validation in larger studies.