Presurgical circulating platelet-derived microparticles level as a risk factor of blood transfusion in patients with valve heart disease undergoing cardiac surgery.

BACKGROUND: Cell-derived microparticles (MPs) are membrane vesicles that have emerged as a potential biomarker for various diseases and their clinical complications. This study investigates the role of MPs as a risk factor for blood transfusion in patients with valve heart disease undergoing cardiac surgery. METHODS: Forty adult patients undergoing heart valve surgery with cardiopulmonary bypass (CPB) were enrolled, and venous blood samples were collected prior to surgical incision. Plasma rich in MPs was prepared by double centrifugation, and the concentration of MPs was determined using the Bradford method. Flow cytometry analysis was performed to determine MPs count and phenotype. Patients were divided into "with transfusion" (n = 18) and "without transfusion" (n = 22) groups based on red blood cell (RBC) transfusion. RESULTS: There was no significant difference in MPs concentration between the "with transfusion" and "without transfusion" groups. Although the count of preoperative platelet-derived MPs (PMPs), monocyte-derived MPs (MMPs), and red cell-derived MPs (RMPs) was higher in "without transfusion" group, these differences were not statistically significant. The preoperative PMPs count was negatively correlated with RBC transfusion (P = 0.005, r = -0.65). Multivariate logistic regression analysis revealed that the count of CD41+ PMPs, Hemoglobin (Hb), and RBC count were risk factors for RBC transfusion. CONCLUSION: This study suggests that the presurgical levels of PMPs, Hb, and RBC count can serve as risk factors of RBC transfusion in patients with valve heart disease undergoing cardiac surgery. The findings provide insights into the potential use of MPs as biomarkers for blood transfusion prediction in cardiac surgery.

Correlations between the Circulating Level of Cell-Derived Microparticles and Surgical Variables in Heart Valve Surgery with Cardiopulmonary Bypass.

Background: Cell-derived microparticles (MPs) as membrane vesicles are procoagulant. They play a role in surgical hemostasis. In this study, the correlations between the circulating level of cell-derived MPs and surgical variables in heart valve surgery were investigated. Methods: The present prospective case-series study was conducted in Rajaie Cardiovascular Medical and Research Center from January through March 2021. Forty patients undergoing heart valve surgery with cardiopulmonary bypass (CPB) were enrolled. Before the induction of anesthesia and 30 minutes after the administration of protamine sulfate, venous blood samples were collected. After MP isolation, the concentration of MPs was determined via the Bradford method. Flow cytometry analysis was performed to determine the MP count and phenotype. Intraoperative variables and postoperative routine coagulation tests were defined as surgical variables. Postoperative coagulopathy was defined as an activated partial thromboplastin time (aPTT) ≥48 seconds or an international normalized ratio (INR) >1.5. Results: The total concentration of MPs and the MP count increased significantly after surgery compared with before surgery. The postoperative concentration of MPs was positively correlated with the CPB time (P=0.030, ρ=0.40). The preoperative concentration of MPs was significantly lower in patients with higher postoperative aPTT and INR (P=0.003, P= -0.50 and P=0.020, P= -0.40, respectively). In multivariate logistic regression analysis, the preoperative MP concentration (OR, 1.00; 95% CI, 1.00 to 1.01; P=0.017) was considered a risk factor for postoperative coagulopathy. Conclusion: The levels of MPs, especially platelet-derived MPs, rose after surgery, in correlation with the CPB time. Given the role of MPs in the induction of coagulation and inflammation, they can be considered therapeutic goals for preventing postoperative complications. In addition, the preoperative levels of MPs are a risk factor for predicting the occurrence of postoperative coagulopathy in heart valve surgery.

Role of Using a Thromboelastometry-Based Protocol for Transfusion Management in Combined Coronary Artery Bypass Grafting and Valve Surgery: A Randomized Clinical Trail.

The aim of this study was to evaluate the impact of using a thromboelastometry-based protocol on transfusion requirements in patients undergoing combined coronary artery bypass grafting (CABG) and valve surgery. 80 adult patients scheduled for elective combined CABG and valve surgery were included in this clinical trial study. Patients were randomly allocated to the thromboelastometry (ROTEM) (n = 40) or control groups (n = 40). In the ROTEM group, transfusion was directed according to a thromboelastometry-based protocol. In the control group, transfusion was conducted according to the routine practices including conventional coagulation testing and clinical judgments. Finally, transfusion requirements were compared between groups. Use of thromboelastometry- based protocol resulted in 67% reduction in blood products units' consumption as well as 23% in the percentage of patients transfused. This reduction was especially evident in relation to fresh frozen plasma (FFP) and platelet consumption. No significant differences were found both in the percentage of patients receiving RBC and number of transfused RBC units. Using thromboelastometry tests incorporated a protocol results in reduction of transfusion requirements in patients undergoing elective combined CABG and valve surgery.

Effect of Mesenchymal Stem Cell-derived Microvesicles on Megakaryocytic Differentiation of CD34+ Hematopoietic Stem Cells.

Purpose: Mesenchymal stem cells (MSCs) release hematopoietic cytokines, growth factors, and Microvesicles (MVs) supporting the hematopoietic stem cells (HSCs). MVs released from various cells, playing a crucial role in biological functions of their parental cells. MSC-derived MVs contain microRNAs and proteins with key roles in the regulation of hematopoiesis. Umbilical cord blood (UCB) is a source for transplantation but the long-term recovery of platelets is a main problem. Therefore, we intend to show that MSC-MVs are able to improve the differentiation of UCB-derived CD34+ cells to megakaryocyte lineage. Methods: In this descriptive study, MSCs were cultured in DMEM to collect the culture supernatant, which was ultracentrifuged for the isolation of MVs. HSCs were isolated from UCB using MACS method and cultured in IMDM supplemented with cytokines and MVs in three different conditions. Megakaryocyte differentiation was evaluated through the expression of specific markers and genes after 72 hours, and the data was analyzed by t test (P<0.05). Results: The expression of specific megakaryocyte markers (CD41 and CD61) in the presence of different concentrations of MSC-MVs did not show any significant difference. Also, the expression of specific genes of megakaryocyte lineage was compared with control group. The expression of GATA2 and c-Mpl was significantly increased, GATA1 was not significantly decreased, and FLI1 was significantly decreased. Conclusion: MSC-MVs could improve the expression of specific megakaryocyte genes; however, there was no significant expression of CD markers. Further studies, including the evaluation of late stages of megakaryocyte differentiation, are required to evaluate platelet production and shedding.

Comparison of standard coagulation testing with thromboelastometry tests in cardiac surgery.

Introduction: According to the several evidences, using thromboelastometry as a point of care test can be effective in reduction in blood loss and transfusion requirements in cardiac surgeries. However, there are limited data regarding to the comparison of thromboelastometry and the standard coagulation tests. In this study, we compared thromboelastometry and standard coagulation tests (PT, PTT and fibrinogen level) in patients under combined coronary-valve surgery. Methods: Forty adult patients who were under on-pump combined coronary-valve surgery were included in this study. Thromboelastometry tests Fibtem, Intem, Extem and Heptem), along with standard coagulation tests (PT, PTT and fibrinogen assay) were simultaneously performed in two time points, before and after the pump (pre-CPB and post-CPB, respectively). Results: A total of 80 blood samples were analyzed. There were no significant correlation between PT test and the CT-Extem parameter as well as PTT and CT-Intem parameter either in pre-CPB and post-CPB (P >0.05). On the contrary, fibrinogen level had high correlation with A10-Fibtem and A10-Extem in pre-PCB (P <0.05). 82% of PT and 84% of PTT measurements were outside the reference range, while abnormal CT in Extem and Intem was observed in 17.9%. Conclusion: For management of bleeding, adequate perioperative haemostatic monitoring is indispensable during cardiac surgery. Standard coagulation tests are time consuming and cannot be interchangeably used with thromboelastomety and relying on their results to decide whether blood transfusion is necessary, leads to the inappropriate transfusion.

Perioperative changes in platelet count and function in patients undergoing cardiac surgery.

Background: Patients undergoing cardiac surgery are at increased risk of bleeding due to multifactorial coagulopathies. In the present study, we aimed at investigating the changes in platelet count and function during and after surgery as well as determining the association of the platelet dysfunction with bleeding and transfusion requirements in these patients. Methods: A total of 40 adult patients scheduled for elective valve coronary cardiac surgery were included in this prospective observational study. Changes in platelet count and function with ADP, acid arachidonic, and collagen (light transmission aggregometry) were analyzed at three time points: before CPB, after CPB, and 24 hours after end of surgery. Postoperative bleeding and intraoperative transfusion requirements were recorded. Results: There were a significant reverse correlation between CPB time and ADP-induced aggregation, particularly after CPB and postoperative AA-induced aggregation. There was not any significant correlation between platelet count and function at all-time points. Both platelet count and platelet aggregation significantly reduced during CPB. While platelet aggregation increased on postoperative Day 1, platelet count reduced by about 40% after CPB, and remained at this level postoperatively. Patients with abnormal ADP-induced aggregation had significant increased postoperative bleeding and transfusion requirements. Conclusion: The results of this study demonstrate that platelet count and platelet aggregation are reduced during CPB. Our results emphasized the effect of platelet dysfunction on increased postoperative bleeding and transfusion requirements. Perioperative monitoring of platelet function can be considered as a bleeding management strategy for implantation of PBM programs.