Activated platelets are involved in blood coagulation by exposing phosphatidylserine (PS), which serves as a substrate for assembling coagulation complexes. Platelets accelerate fibrin formation and thrombin generation, two final reactions of the coagulation cascade. We investigated the effects of antiplatelet drugs on platelet impact in these reactions and platelet ability to expose PS. Washed human platelets were incubated with acetylsalicylic acid (ASA), ticagrelor, ASA in combination with ticagrelor, ruciromab (glycoprotein IIb-IIIa antagonist), or prostaglandin E1 (PGE1). Platelets were not activated or activated by collagen and sedimented in multiwell plates, and plasma was added after supernatant removal. Fibrin formation (clotting) was monitored in a recalcification assay by light absorbance and thrombin generation in a fluorogenic test. PS exposure was assessed by annexin V staining using flow cytometry. Ticagrelor (alone and in combination with ASA), ruciromab, and PGE1, but not ASA, prolonged the lag phase and decreased the maximum rate of plasma clotting and decreased the peak and maximum rate of thrombin generation. Inhibition was observed when platelets were not treated with exogenous agonists (activation by endogenous thrombin) and pretreated with collagen. Ticagrelor (alone and in combination with ASA), ruciromab, and PGE1, but not ASA, decreased PS exposure on washed platelets activated by thrombin and by thrombin + collagen. PS exposure on activated platelets in whole blood was lower in patients with acute coronary syndrome receiving ticagrelor + ASA in comparison with donors free of medications. These results indicate that antiplatelet drugs are able to suppress platelet coagulation activity not only in vitro but also after administration to patients.

Aim. To study the outcomes frequency and structure in patients with atrial fibrillation (AF) depending on the cardioembolic events preventing method: left atrial appendage (LAA) isolation, direct oral anticoagulants (DOACs) or warfarin.Material and methods. A prospective observational study included patients with AF and high risk of cardioembolic complications and without contraindications to anticoagulants. Patients who refused long-term oral anticoagulants taking underwent LAA isolation, the rest of the patients received DOACs or warfarin. The observation period was 3 years. Mortality, cardioembolic complications and major bleeding (according to GARFIELD criteria) cumulative incidence was assessed.Results. We included 245 patients: 46 patients were treated with LAA isolation, 100 with warfarin, and 99 with DOACs. Multivariate regression analysis demonstrated a statistically significant advantage of LAA occluder in terms of combined endpoint achieving frequency compared to warfarin (hazard ratio [HR] 3.10; 95% confidence interval [CI] 1.01-9.54; p=0.049), and to DOACs (HR 3.44, 95% CI 1.15-10.29; p=0.027). A similar result was obtained for all-cause mortality (HR 5.24; 95% CI 1.12-24.55; p=0.036 and HR 5.58; 95% CI 1.22-25.49; p=0.027, respectively). There were no significant differences in bleeding rates between the groups.Conclusion. This observational study demonstrates the superiority of LAA isolation as a first-line therapy over DOACs and warfarin in patients with AF and high risk of cardioembolic complications. Randomized trials are required to confirm these observations.

Activated platelets are involved in blood coagulation by exposing phosphatidylserine (PS), which serves as a substrate for assembling coagulation complexes. Platelets accelerate fibrin formation and thrombin generation, two final reactions of the coagulation cascade. We investigated the effects of antiplatelet drugs on platelet impact in these reactions and platelet ability to expose PS. Washed human platelets were incubated with acetylsalicylic acid (ASA), ticagrelor, ASA in combination with ticagrelor, ruciromab (glycoprotein IIb-IIIa antagonist) or prostaglandin E1 (PGE1). Platelets were not activated or activated by collagen, sedimented in multiwell plates and plasma was added after supernatant removal. Fibrin formation (clotting) was monitored in a recalcification assay by light absorbance and thrombin generation in a fluorogenic test. PS exposure was assessed by annexin V staining using flow cytometry. Ticagrelor (alone and in combination with ASA), ruciromab and PGE1, but not ASA prolonged the lag phase and decreased the maximum rate of plasma clotting, and decreased the peak and maximum rate of thrombin generation. Inhibition was observed when platelets were not treated with exogenous agonists (activation by endogenous thrombin) and pretreated with collagen. Ticagrelor (alone and in combination with ASA), ruciromab and PGE1, but not ASA decreased PS exposure on washed platelets activated by thrombin and by thrombin + collagen. PS exposure on activated platelets in whole blood was lower in patients with acute coronary syndrome receiving ticagrelor + ASA in comparison with donors free of medications. These results indicate that antiplatelet drugs are able to suppress platelet coagulation activity not only in vitro but also after administration to patients.

Objective: comparison of general anesthesia (GA) and intravenous conscious sedation during left atrial appendage occlusion (LAAO).Materials and Methods. The study included 120 patients from LAAO Register at the National Medical Research Center of Cardiology, who were divided into GA (n = 100) and intravenous sedation (n = 20) groups. In-hospital outcomes were assessed, as well as outcomes and data of transesophageal echocardiography (TEE) at 45 days and 6 months.Results. 3 patients required intraoperative conversion of the anesthetic method to GA. The duration of the procedure, the time of fluoroscopy, the amount of contrast medium, and the technical success did not differ signifcantly between the two groups. The incidence of in-hospital complications in the GA group was 10%, and 15% in the intravenous sedation group (p = 0.453). There were no statistically signifcant differences between the groups in long-term outcomes and TEE data after 45 days and 6 months.Conclusion. Combined intravenous sedation with local anesthesia is an effective and fairly safe method of anesthesiological support for implantation of the occluder of the left atrial auricle. It can be used in patients with a high risk of GA, with predictable difculties of tracheal intubation, as well as if the patient wishes accordingly. The limitations of the use of intravenous sedation in combination with local anesthesia are anatomical variants of SFM that are difcult for occluder implantation, as well as the patient's low tolerance to ECG in consciousness.