[Platelet adhesion mediated by von Willebrand factor in patients with premature coronary artery disease].

Aim    To study platelet adhesion mediated by von Willebrand factor (VWF) in patients with premature ischemic heart disease (IHD).Material and methods    This study enrolled 58 patients with stable IHD, including 45 men younger than 55 years with the first manifestation of IHD at the age of <50 years and 13 women younger than 65 years with the first manifestation of IHD at the age of <60 years. The control group consisted of 33 patients, 13 men younger than 55 years and 20 women younger than 65 years without IHD. Platelet adhesion to the collagen surface at the shear rate of 1300 s-1 was studied by evaluating the intensity of scattered laser light from the collagen-coated optical substrate in a flow chamber of a microfluidic device after 15-min circulation of whole blood in the chamber. Decreases in platelet adhesion after addition to the blood of monoclonal antibodies (mAb) to platelet receptors glycoproteins Ib (GPIb) to inhibit the receptor interaction with VWF were compared for patients of both groups. Results    In patients with premature IHD, the decrease in platelet adhesion following the platelet GPIb receptor inhibition was significantly less than in patients of the control group (74.8 % (55.6; 82.7) vs. 28.9 % (-9.8; 50,5), p <0.001). For the entire sample, the median decrease in platelet adhesion following the GPIb receptor inhibition was 62.8 % (52.2; 71.2). With an adjustment for traditional risk factors of IHD, a decrease in platelet adhesion of >62.8% after blocking GPIb receptors increased the likelihood of premature IHD (OR=9.84, 95 % CI: 2.80-34.59; p <0.001).Conclusion    Blocking the interaction of GPIb receptors with VWF in patients with premature IHD and increased shear rate induced a greater decrease in platelet adhesion than in patients without this disease. This suggested that an excessive interaction of VWF with platelets might contribute to the pathogenesis of premature IHD.

Monomeric form of C-reactive protein in the assessment of the residual inflammatory cardiovascular risk in patients with subclinical carotid atherosclerosis.

Aim      To study the relationship between monomeric C-reactive protein (mCRP) and the progression of asymptomatic carotid atherosclerosis in patients with a moderate risk for cardiovascular diseases (CVD) as assessed with the SCORE model.Material and methods  The study included 80 men and women aged 53.1±5.8 years assigned to the category of a moderate risk for CVDs by the SCORE model with a low-density lipoprotein cholesterol (LDL-C) level of 2.7-4.8 mmol/l and asymptomatic, hemodynamically insignificant (<50% luminal narrowing) carotid atherosclerosis according to ultrasonic data. All patients were prescribed atorvastatin to achieve a LDL-C level <2.6 mmol/l. After 7 years of follow-up, ultrasonic examination of carotid arteries was performed, and concentrations of high-sensitivity C-reactive protein (hsCRP) and mCRP were measured.Results A concentration of LDL-C <2.6 mmol/l was achieved in all patients. The progression of atherosclerosis as determined by an increased number of atherosclerotic plaques (ASPs), was observed in 45 (56 %) patients. At 7 months of follow-up, concentrations of cCRP were higher in the group of patients with progressive carotid atherosclerosis, while the levels of hsCRP did not differ between the groups. Increased mCRP concentrations were associated with changes in variables of the "atherosclerotic load", including the number of ASPs, total ASP height, and the intima-media thickness (IMT). In patients with a median mCRP concentration of 5.2 [3.3; 7.1] µg/l and more, the increases in mean ACP number and total ASP height were considerably higher than in patients with mCRP concentrations lower than the median (3.9 and 2.7 times, respectively), whereas the odds ratio for the progression of asymptomatic carotid atherosclerosis was 5.5 (95 % confidence interval, CI: 2.1-14.6; p=0.001). ROC analysis showed that the concentration of hsCRP had no predictive value for prognosis of asymptomatic carotid atherosclerosis (p=0.16), while the area under the ROC curve (AUC) for mCRP was 0.75±0.056 (95 % CI: 0.64-0.86; p=0.001).Conclusion      According to the results of 7-year follow-up, the plasma concentration of mCRP was significantly higher in patients with an increased number of ASPs than in patients without this increase. An increased level of mCRP may indicate a higher inflammatory risk of CVD.

Complex Interaction of Platelets, von Willebrand Factor and Leukocytes, in Whole Blood at High Shear Rates Is Mediated by Platelet GPIIb/IIIa Receptor.

We studied the contribution of von Willebrand factor (vWF) into blood cell adhesion to collagen-coated surfaces in whole blood of healthy volunteers. Adhesion of blood cells to collagen I was measured at shear rate of 2300 sec-1. The interaction of platelet GPIIb/IIIa receptor with vWF was blocked with monoclonal anti-GPIIb/IIIa antibodies. The degree of cell adhesion was quantified by measuring the intensity of scattered light after 15-min perfusion: in samples with blocked GPIIb/IIIa it decreased to 0.39±0.13 V vs 0.06±0.03 V in control samples (p=0.002). Under a fluorescence microscope, intensively stained structures consisting of vWF, platelets, and leukocytes attached to the collagen surface were observed. After blockade of GPIIb/IIIa, these structures were absent. Leukocyte recruitment at high shear rates is a time-dependent process sensitive to complex interaction of vWF, leukocytes, and platelets, in which the platelet GPIIb/IIIa receptor is essential.

Kinetics of Platelet Adhesion to Protein-Coated Surface in Whole Blood Samples at High Flow Rates.

We studied platelet adhesion to fibrinogen-coated surface in whole blood samples under conditions of high flow rates. The degree of platelet adhesion was evaluated by the intensity of laser light scattered from protein-coated optical surface with adhered platelets. The intensity of adhesion in whole blood samples at high flow rates was by 2.7 (2.4; 4.1) times higher than in platelet-rich plasma samples. Among the factors intensifying platelet adhesion in the whole blood at high flow rates, von Willebrand factor is of utmost importance. At low flow rates, platelet adhesion almost totally depends on platelet-fibrinogen interaction. At high flow rates, the interactions of platelets with both fibrinogen and von Willebrand factor become equally important.

[Acute Coronary Syndrome Registry of High Risk Patients: 30-Day Outcome].

AIM: The aim of the study is to evaluate important additional cardiovascular (CV) risk factors of major adverse cardiac events (MACE) in patients with acute coronary syndrome (ACS) during the first 30 days after index event. MATERIALS AND METHODS: Overall 750 patients with ACS were enrolled in the single center prospective registry from 2012-2015yy. 569 patients received dual antiplatelet therapy and in 425 cases platelet function testing (PFT) were performed. Most of the patients characterized as high risk elderly patients with multiple CV risk factors and high comorbidity index. RESULTS: At 30-day follow-up the mortality rate was 10,1%. Singlevariate analysis showed strong association between MACE and age, atrial fibrillation, stroke, chronic kidney disease, low ejection fraction, type 2 myocardial infarction (T2MI). Multivariate analysis showed that high-on-treatment platelet reactivity (PFT> 45%) with odds ratio 4.418 (p=0.0001), chronic kidney disease (OR 6.538 p=0.001) and T2MI (OR 1.925 p=0.0001) were significantly associated with adverse outcome. CONCLUSION: ACS registry showed high mortality level in real-life practice compared with randomized clinical trials due to the high prevalence of elderly patients with high comorbidity index. Patients with T2MI have significantly more severe prognosis and chronic kidney disease associated with increased MACE. PFT in this category of patients is reasonable for more accurate risk stratification.

[Relation of Functional Activity of Platelets to Prognosis of Unfavorable Cardiovascular Events in Patients with Acute Coronary Syndrome. Results of a Registry Study].

AIM: to assess relation ofhigh functional activity ofplatelets to prognosis ofunfavorable cardiovascular events in patients with Acute Coronary Syndrome (ACS). MATERIALS: The study was based on the data of a single center ACS registry conducted in the Central Clinical Hospital of the Presidential Affairs Department of Russian Federation. Of 529 included patients in 425 without contraindications to double antiplatelet therapy we carried out analysis of dependence of 30 days level of unfavorable events on parameters of functional activity of platelets. RESULTS: High on-treatment platelet reactivity (HTPR) was found to be associated with 3.5 increase of mortality in the group of patients with high cardiovascular risk. Logistic model of prognosis of unfavorable events based on multifactorial analysis of data from patients with measured platelet aggregation included chronic kidney disease, type of myocardial infarction, and degree ofplatelet aggregation >45%. C -statistic was equal to 0.77. We also present in this paper discussion of problems related to studying approaches to individualization of anti-aggregation therapy in real clinical practice and problems of organization ofsimilar studies. CONCLUSION: The study showed that patients with ACS increased platelet aggregation, as well as chronic kidney disease and type 2 MI are associated with a 30 day prognosis of adverse events.

Real-Time Recording of Platelet Adhesion to Fibrinogen-Coated Surface under Flow Conditions.

We present a testing system allowing real-time recording of the kinetics of platelet adhesion to fibrinogen-coated surface under flow conditions. The system consists of an optical flow chamber, semiconductor laser, two photodetectors, analog-to-digital converter, computer, and peristaltic pump. Platelet adhesion to fibrinogen-coated surface is recorded with two photodetectors and analyzed by the intensity of total internal reflection and scattered laser radiation at the boundary of the blood sample and fibrinogen-coated optical surface. Kinetics of platelet adhesion was studied as a function of shear rate and platelet concentration. The specificity of platelet adhesion with proteins on the surface of the flow chamber was verified by blocking IIb/IIIa glycoprotein complex on platelets with Fab2 fragments of monoclonal antibodies.

[The CD45-positive thrombocytes and neutrophils/lymphocytes level ratio in evaluation of risk of development of re-stenosis шт patients with chronic ischemic heart disease and diabetes mellitus type II.]

The purpose of study is to investigate significance of detection of number of CD45-positive thrombocytes and ratio neutrophils/lymphocytes in evaluation of risk of development of re-stenosis after implantation of drug-eluting stents in patients with chronic ischemic heart disease and diabetes mellitus type II. The examination was applied to 126 patients with chronic forms of ischemic heart disease who passed through repeat coronary angiography during first year after implantation of drug-eluting stents. The patients were separated on two groups depending on availability of diabetes mellitus type II. In both groups, the patients passed through comparing of angiography and clinical characteristics. Also, a logistic model was developed prognosticating development of re-stenosis. The re-stenosis developed more often in patients with diabetes mellitus type II (54.5%) than in patients without diabetes mellitus type II (32.4%; p=0.01). The comparative analysis of more than 35 characteristics permitted to establish risk factors of development of re-stenosis with the highest prognosticating capacity among patients with diabetes mellitus type II. These risk factors were CD45-positive thrombocytes and ratio neutrophils/lymphocytes. To prognosticate development of re-stenosis a logistic regression model was developed comprising number of circulating CD45-positive thrombocytes, ratio neutrophils/lymphocytes and availability of diabetes mellitus type II. The model demonstrated high prognosticating value as regards development of re-stenosis: OR = 15.1 (95% CI 4.81-31, p < 0.001). The square under ROC-curve: AUC = 0.83 (95% CI 0,72-0,92; р < 0,001). The increasing of number of circulating CD45-positive thrombocytes and ratio neutrophils/lymphocytes can be considered as a valuable risk factors of development of re-stenosis in case of diabetes mellitus type II.

Relationship between the Level of Circulating CD45+ Platelets and Development of Restenosis after Implantation of Drug-Eluting Stents to Patients with Coronary Heart Disease.

The study was carried out in 126 patients with stable angina pectoris, who underwent elective coronary artery stenting with drug-eluting stents and follow-up angiography within 6-12 months thereafter. Five significant risk factors of restenosis were identified by binary comparisons of different variables. The logistic regression equation that included the level of CD45-positive platelets, diabetes, small vessel stenting, number of simultaneously implanted stents in one patient, and lesion length demonstrates the highest level of prediction of in-stent restenosis (OR=22.8; p<0.001). ROC-analysis demonstrated high prognostic value of the logit model (area under ROC curve 0.87, p<0.001). The data suggest that a close relationship exists between the development of restenosis and the level of circulating CD45+ platelets.

Acetylsalicylic Acid Produces Different Effects on the Production of Active Oxygen Species by Activated Platelets in Different Inflammatory Diseases.

We studied the effect of acetylsalicylic acid on ROS generation by platelets in patients after surgical interventions and in patients with bronchial asthma was studied. Platelets stimulated with platelet-activating factor are characterized by weak luminol-enhanced chemiluminescence in healthy people and patients after operations with laparoscopic incisions. Addition of platelet activation factor to platelet samples from patients after open abdominal surgery caused intensive chemiluminescence that was suppressed after platelet incubation with acetylsalicylic acid. At the same time, platelets of patients with aspirin-sensitive asthma did not respond to addition of platelet activating factor, but after incubation with acetylsalicylic acid, an intensive burst of chemiluminescence was detected with a maximum in 5-10 sec after the addition of a platelet-activating factor. In patients with bronchial asthma tolerant to aspirin, platelet activation factor did not induce chemiluminescence irrespective of incubation with acetylsalicylic acid.