Retransfusion of pericardial blood does not trigger systemic coagulation during cardiopulmonary bypass

Abstract

Objective: During cardiopulmonary bypass (CPB), systemic coagulation is believed to become activated by blood contact with the extracorporeal circuit and by retransfusion of pericardial blood. To which extent retransfusion activates systemic coagulation, however, is unknown. We investigated to which extent retransfusion of pericardial blood triggers systemic coagulation during CPB. Methods: Thirteen patients undergoing elective coronary artery bypass grafting surgery were included. Pericardial blood was retransfused into nine patients and retained in four patients. Systemic samples were collected before, during and after CPB, and pericardial samples before retransfusion. Levels of prothrombin fragment F 1+2 (ELISA), microparticles (flow cytometry) and non-cell bound (soluble) tissue factor (sTF; ELISA) were determined. Results: Compared to systemic blood, pericardial blood contained elevated levels of F 1+2 , microparticles and sTF. During CPB, systemic levels of F 1+2 increased from 0.28 (0.25-0.37; median, interquartile range) to 1.10 (0.49-1.55) nmol/l ( p = 0.001). This observed increase was similar to the estimated (calculated) increase ( p = 0.424), and differed significantly between retransfused and non-retransfused patients (1.12 nmol/l vs 0.02 nmol/l, p = 0.001). Also, the observed systemic increases of platelet-and erythrocyte-derived microparticles and sTF were in line with predicted increases ( p = 0.868, p = 0.778 and p = 0.205, respectively). Before neutralization of heparin, microparticles and other coagulant phospholipids decreased from 464 mg/ml (287-701) to 163 mg/ml (121-389) in retransfused patients ( p = 0.001), indicating rapid clearance after retransfusion. Conclusion: Retransfusion of pericardial blood does not activate systemic coagulation under heparinization. The observed increases in systemic levels of F 1+2 , microparticles and sTF during CPB are explained by dilution of retransfused pericardial blood. #

Transfusion of autologous extracellular vesicles from stored red blood cells does not affect coagulation in a model of human endotoxemia

“…This is in line with a previous study in coronary artery bypass patients who underwent retransfusion of pericardial blood containing high levels of EVs. Although the vesicles isolated from pericardial blood increased thrombin generation in vitro, infusion of these vesicles did not have an in vivo effect on systemic coagulation . We feel that dilution of the infused vesicles following transfusion more closely resembles a relevant clinical situation than does measuring effects of a whole blood unit.…”

“…Another factor that may account for the differences are the use of autologous blood instead of allogeneic transfusion products. The studies that reported effects of transfusion products on coagulation parameters used allogeneic products, whereas studies that did not report an effect, including our own, used autologous products …”

Exosomes and microvesicles in normal physiology, pathophysiology, and renal diseases

“…Microvesicles released into the circulation have a half-life of a couple of minutes to a few hours [38], during which they may be taken up by neighboring or distant cells. In humans undergoing cardiopulmonary bypass, transfusion or dobutamine-induced cardiac stress, elevated levels of circulating microvesicles were detected, but these returned to baseline levels within 15 min to ~6 h [39, 40]. Interestingly, clearance of microvesicles may depend on the cellular origin of the microvesicles as platelet-derived microvesicles were cleared sooner than microvesicles released from red blood cells [40].…”

Complement activation on the surface of cell-derived microparticles during cardiac surgery with cardiopulmonary bypass - is retransfusion of pericardial blood harmful?

“…The study design has been detailed previously. 20 Briefly, thirteen patients who underwent elective coronary artery bypass grafting assisted by CPB were included prospectively. Inclusion criteria were body surface area >1.66 m 2 and preoperative hemoglobin levels >7.5 mmol/L.…”

“…Two of the patients who were retransfused with pericardial blood also received allogeneic blood products (red cell concentrates). For a description of the extracorporeal system and the surgical procedure see the manuscript of van den Goor et al 20 This study was approved by the ethical committee of the Academic Medical Center of the University of Amsterdam and complies with the principles of the Declaration of Helsinki. All patients had given their written informed consent.…”