Platelet aggregation in patients with chronic heart failure in a "vortex" flow

Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): Исследование выполнено в рамках фундаментальной темы НИИ кардиологии АААА-А15-115123110026-3. Platelet aggregation mechanisms are studied using standard methods without taking turbulence into account. However, in cardiovascular diseases, the blood rheology changes, and the parameters of the turbulent flow acquire strong prothrombotic effects. The adhesion of several platelets creates a "snowball" effect with platelet hyperaggregation, leading to rapid vessel occlusion. Thus, the study of platelet aggregation in patients with cardiovascular diseases in conditions of creating a "vortex" flow in platelet-rich plasma is very relevant. Objective to study the effect of "vortex" flow in platelet-rich plasma on spontaneous and epinephrine-induced platelet aggregation in patients with CHF. Material and method. We studied 15 patients (75% of them men) with CHD, having CHF I-III FC. Platelet aggregation activity was studied using a turbidimetric method using a laser analyzer (220 LA "NPF Biola", Russia). Platelet aggregation activity in platelet-rich plasma (BTP) was estimated by light transmission curves in % and average aggregate size in relative units (Rel. units), with the inducer epinephrine in concentrations of 2 and 10 mg/ml, with constant stirring at 800 rpm. The same parameters were evaluated byour ownproposed approach with a creation ofa "vortex" plasma flow, which were achieved by changing the mixing rate of BTP from 0 to 800 rpm. Aggregation data is presented as a median with an interquartile range (Me (Q1; Q3)). Statistical data processing was performed using SPSS packages (version 19). The differences were considered significant at a significance level of p < 0.05. Results. In patients with CHF, the indicators of spontaneous aggregation measured by the standard method were 3.1 (1.5; 4.0) % and 1.7 (1.1; 2.0) Rel. units. Under the conditions of a"vortex" flow, the aggregate size increased to 5.4 (3.2; 6.1) Rel. units(p = 0.04). The indicators of standard epinephrine-induced aggregation at a concentration of 2 mg/ml were 46.7 (35.8; 66.2) % and 15.0(11.4; 18.9) Rel. units, and when the mixing speed was changed from 0 to 800 rpm, the indicators increased to 52.7 (41.3; 76.5) % (p = 0.003) and 19.4 (17.3; 20.6) Rel. units(p = 0.04). In conditions of increased epinephrine concentration of 10 mg/ml, the indicators were 52.5 (41.9; 74.5) % (p = 0.03) and 15.8 (12.2; 18.4) Rel. units. Under the conditions of"vortex" flow, aggregation indicators were 75.4 (62.0; 80.5)% (p = 0.04), and the size of aggregates increased to 356.0 (230.5; 462.5) Rel. units. Conclusion. Standard methods for studying of platelet aggregation are not always sufficient to detect an increased pro-aggregative potential of platelets. The proposed method for creationof "vortex" flow conditions showed an increase in the size of platelet aggregates and the degree of aggregation against the background of increased epinephrine concentration in patients with chronic heart failure, which proves its effectiveness in detecting platelet hyperaggregation.

Effect of perioperative infusion therapy on the functional state of the hemostatic system in patients with concomitant coronary heart disease

Background. The choice of the infusion therapy regimen in the perioperative period remains a complex and controversial issue of modern anesthesiology. This is especially true for elderly patients with concomitant cardiovascular diseases, primarily coronary heart disease (CHD). Excessive fluid restriction in the perioperative period during the intervention can contribute to the development of arterial hypotension and hypoperfusion of vital organs. At the same time, excessive fluid intake in these patients is dangerous in terms of developing complications such as decompensation of heart activity, ischemic myocardial damage. There are many factors of the perioperative period that affect the processes of fluid metabolism in the body, the state of hemodynamics and other vital functions. Among them, the most significant factors are operational stress, features of the underlying disease and surgical intervention, the influence of anesthetics, the functional state of the cardiovascular system, kidneys, etc. One of the insufficiently considered factors that may influence the choice of infusion therapy, in our opinion, is the functional state of the hemostatic system in the preoperative period. Objective. To investigate the effect of perioperative infusion therapy on the functional state of the hemostatic system in patients with concomitant CHD. Materials and methods. A total of 92 patients who underwent abdominal surgery under combined general anesthesia with a ventilator were examined. The average age of patients was 61±12 years; risk on the ASA scale – II-III; risk of cardiac complications on the RCRI – 1-3; risk of thrombosis on the Caprini scale – 6.5±0.1. The functional state of platelets was assessed using the platelet aggregation analyzer AR 2110 (Belarus); the state of plasma hemostasis was assessed using standard coagulogram indicators. Results and discussion. When studying platelet aggregation in the initial state, significant fluctuations in the studied parameters were found from significant hypoaggregation to significant platelet hyperaggregation. For further analysis and differential correction, patients were divided into three groups depending on the degree of platelet aggregation. Group 1 included 22 patients with established hypoaggregation, 2nd group – 38 patients with established normal platelet aggregation, and 3rd group – 32 patients with platelet hyperaggregation. The coagulogram in the majority of patients in the initial state characterized normocoagulation or a tendency to hypercoagulation. Correction of changes in primary hemostasis was performed using infusion therapy, depending on the initial data of platelet aggregation. In the group with greegreece platelets was conducted infusion therapy with the liberal type – 5-10 ml/kg/h for intraoperative stage and 20-25 ml/kg/day after surgery; in the group with hoareau for restrictive type an average of 3-5 ml/kg/h for intraoperative stage and 20-25 ml/kg/day after surgery; in the group with normoergic the relatively restrictive type that was 5-7 ml/kg/h intraoperatively; 25 ml/kg/day after surgery. For specific correction of platelet-vascular hemostasis, etamzilate 12.5 % 4.0 ml was used in group 1 patients before surgery and later 4.0 ml three times a day; in group 3 patients, pentoxifylline 2 % 5.0 ml twice a day. Thromboprophylaxis with low-molecular-weight heparins in the perioperative period was performed in all patients according to current recommendations. As a result of this approach to the correction of established disorders of platelet-vascular hemostasis, a clear trend towards normalization of the studied parameters was established already at the intraoperative stage, this trend persisted a day after the operation. Thus, the indicators of platelet aggregation in group 1 patients at the intraoperative and early postoperative stages were 68.2 (59.5; 78.1) and 63.6 (60; 72.6); in group 3 patients – 79.7 (75.3; 94.2) and 74.6 (59.2; 83.4), respectively. Conclusions. Individualized infusion and pharmacological therapy allows correction of disorders of platelet-vascular hemostasis in patients with concomitant CHD, which may be useful for reducing the risk of thrombotic complications.

Endothelial Dysfunction and Platelet Hyperaggregation in type 2 Diabetes Mellitus: The era of novel anti-diabetic agents

Background: Diabetes mellitus (DM) incidence is ever-increasing and along with its microvascular and macrovascular complications is associated with a high morbidity and mortality burden globally. Major components of diabetes pathophysiology include glucotoxicity, lipotoxicity and insulin resistance, disturbing the vascular wall integrity and leading to endothelial dysfunction and platelet hyperaggregation. Objective: This review aims to identify and summarize the effect of novel anti-diabetic agents (glucagon-like peptide-1 receptor agonists, dipeptidyl peptidase-4 inhibitors, sodium-glucose co-transporter -2 inhibitors) on endothelial (EF) and platelet function (PF) and evaluate the consistency with the results of cardiovascular outcomes studies. Methods: We performed a structured search of the PubMed database for peer-reviewed research of the literature between 1981 and 2020 regarding the effect of DM and novel anti-diabetic agents on EF and PF. Results: We analyzed data regarding the effect of novel anti-diabetic agents on EF and PF as well as the pathophysiological interplay between DM, PF, and EF. The available studies use different methods to evaluate these outcomes and the results of different studies are rather conflicting as a result of different study designs, combinations of drugs tested, small study samples and patient population heterogeneity. Conclusion: The currently available data do not unequivocally support a consistent effect of novel antidiabetic agents on EF and PF. Further study is required ideally with validation of the results with clinical outcomes.

The Main Determinants of Diabetes Mellitus Vascular Complications: Endothelial Dysfunction and Platelet Hyperaggregation

Diabetes mellitus is a common disease that affects 3–5% of the general population in Italy. In some countries of northern Europe or in North America, it can even affect 6–8% of the population. Of great concern is that the number of cases of diabetes is constantly increasing, probably due to the increase in obesity and the sedentary nature of the population. According to the World Health Organization, in the year 2030 there will be 360 million people with diabetes, compared to 170 million in 2000. This has important repercussions on the lives of patients and their families, and on health systems that offer assistance to patients. In this review, we try to describe in an organized way the pathophysiological continuity between diabetes mellitus, endothelial dysfunction, and platelet hyperaggregation, highlighting the main molecular mechanisms involved and the interconnections.

Investigation of platelet aggregation in patients with laryngeal cancer

A comparative study of the induced platelet aggregation in patients with laryngeal cancer to determine the most revealing informative violations. It was compared evaluation of results of platelet aggregation in the blood plasma of patients with laryngeal cancer compared to the healthy persons. It was found intensification of ADP induced platelet aggregation in the concentration range which was used. At the same time with the increase the number of patients with platelet hyperaggregation reliable platelet decrease in blood and increase of patients with thrombocytopenia at the III-rd stage of laryngeal cancer are observed. In patients with lI-nd and III-rd stage of laryngeal cancer was found increase in the level, rate and aggregation time compared to the healthy persons. The most significant violations observed in the II-nd stage of the cancer process.

Aspirin-Platelet Sensitivity in Patients with Essential Thrombocythemia: Role βfibrinogen G-455-a Gene Polymorphism

Essential thrombocythemia (ET) is a myeloid neoplasm characterized by platelet activation and thrombotic risk. Aspirin (ASA) is the standard therapy to normal platelet hyperaggregation and to prevent the thrombosis. It is reported that thrombocythaemic patients are ASA insensitive. It is debated if inherited thrombophilia increases the thrombocythemic platelet activation and, hence, the ASA platelet insensitivity. Therefore, we evaluated βFibrinogen G-455-A gene polymorphism, as thrombophilic molecular mutation associated with increased platelet aggregation, platelet count, β-thromboglobulin (β-TG) and platelet factor 4(PF4) as markers of platelet activation, fibrinogen (Fg), platelet functional activity (PFA), as indicator of ASA platelet sensitivity, clot formation time (CFT) and the maximum clot firmness (MCF), as indicators of aspirinated platelet contribution to clot firmness. We studied 40 patients (24 men, 16 women; mean age 56 years, range 37-77) with ET according to WHO criteria. The mean duration of disease was 11 years. All patients were on ASA 100 mg once daily. The βFibrinogen G455-A genotype was determined using a commercialized polymerase chain reaction kit with sequence-specific primers. Platelets were measured by automated analyzer. β-TG and PF4 were determined by ELISA. PFA, CFT and MCF were measured by Platelet Function Analyzer (PFA-100) and by ROTEM delta, respectively. All patients had heterozygous βFibrinogen G455-A. The mean platelet count was 441±72x109/L. All patients had normal Fg (244±47 mg/dl) high β-TG and PF4 (244±15 IU/ml vs 20±11 IU/ml and 162±56 IU/ml vs 6±2 IU/ml, respectively) (p<.0001 and p<.0001, respectively), prolonged C/EPI closure time (CT, unit: s, n.v. 84-160 s) (252±48 s), normal CFT (CFT, unit: s, n.v. 30-110 s) (50±7s) and MCF (MCF, unit: mm, n.v. 50-72 mm) (71±2 mm). These findings suggest that βFibrinogen G-455-A gene polymorphism does not affect the clonal platelet hyperaggregation in ET. Disclosures No relevant conflicts of interest to declare.

Anti-aggregant activity of new xanthine derivative under conditions of hyper aggregation of platelets in vitro

Aim. To study the anti-aggregant activity and the effectiveness of firstly synthesized cyclohexilammonium salt of 2-[1-ethil-3-methyl-7-(dioxotiethanyl-3)-xantinyl-8-thio]acetic acid as a potential antiplatelet agent under in vitro conditions. Methods. Experimental work was carried out on the blood of healthy donors and 74 male patients diagnosed with thrombosis of various localization. Thromboelastography of citrate blood samples was performed in the presence of the test substances on the device TEG 5000. The analysis determined the overall trend of coagulation, functional activity of platelets and fibrinogen, fibrinolytic activity and physico-mechanical properties of clots formed. ADP-, collagen-, and epinephrine-induced platelet aggregations were registered. Agregatogramm analysis was performed using software AGGR. We evaluated the general nature of the aggregation, the maximum aggregate, maximum aggregation rate, the average size of platelet aggregates. Results. Cyclohexilammonium salt of 2-[1-ethil-3-methyl-7-(dioxotiethanyl-3)-xantinyl-8-thio]acetic acid in in vitro conditions showed anti-aggregant activity greater than the reference substance, and effectively suppress hypercoagulation caused by an excess of thrombin and tissue factor. Conclusion. The results of the study make it possible to establish in a potentially high ex vivo therapeutic effect of a cyclohexilammonium salt of 2-[1-ethil-3-methyl-7-(dioxotiethanyl-3)-xantinyl-8-thio]acetic acid under conditions involving platelet hyperaggregation.