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BACKGROPUND AND AIM Postoperative thrombocytopenia after surgical aortic valve replacement (SAVR) or transcatheter aortic valve replacement (TAVR) and aggravating causes were the aim of this retrospective study. METHODS Data of all patients treated with SAVR (n = 1068) and TAVR (n = 816) due to severe aortic valve stenosis was collected at our center from 2010 to 2017. Preprocedural and postprocedural values were collected from electronic patient records. RESULTS There was a significant drop in platelets in both groups, the TAVR group showed overall superior platelet preservation compared to the AVR group (P

Purpose of review Platelet transfusion is a widely used therapy in treating or preventing bleeding and haemorrhage in patients with thrombocytopenia or trauma. Compared with the relative ease of platelet transfusion, current practice for the storage of platelets is inefficient, costly and relatively unsafe, with platelets stored at room temperature (RT) for upto 5-7 days. Recent findings During storage, especially at cold temperatures, platelets undergo progressive and deleterious changes, collectively termed the 'platelet storage lesion', which decrease their haemostatic function and posttransfusion survival. Recent progress in understanding platelet activation and host clearance mechanisms is leading to the consideration of both old and novel storage conditions that use refrigeration and/or cryopreservation to overcome various storage lesions and significantly extend platelet shelf-life with a reduced risk of pathogen contamination. Summary A review of the advantages and disadvantages of alternative methods for platelet storage is presented from both a clinical and biological perspective. It is anticipated that future platelet preservation involving cold, frozen and/or pathogen reduction strategies in a proper platelet additive solution will enable longer term and safer platelet storage.

Previous work using a 4 h rabbit thrombogenicity model has shown that a nitric oxide (NO)-generating polymer extracorporeal circuit (ECC) with infusion of S-nitroso-N-acetyl-penicillamine (SNAP) preserved platelets even though platelets were activated, as shown by an increase in the glycoprotein p-selectin. The platelet preservation mechanism was shown to be due to a changing fibrinogen structure leading to attenuation of platelet aggregation. To understand the effects that SNAP, another RSNO, S-nitroso-glutathione (GSNO), as well as the non-RSNO, sodium nitroprusside (SNP), may have on human fibrinogen polymerization, this in vitro study evaluated the effects of released NO on thrombin-mediated fibrin formation and fibrinogen structure. Thrombin-induced fibrin formation at 300 μM SNAP (50 + 11% of baseline) was significantly reduced compared to SNAP's parent, N-acetyl-penicillamine (NAP), (95 ± 13%) after 1 h of RSNO exposure. GSNO, its parent, glutathione (GSH), and 1000 ppm NO gas did not attenuate the thrombin-mediated fibrin formation. SNAP, NAP and SNP exposure for 1 h, however, did not decrease thrombin activity by directly inhibiting thrombin itself. Changes in fibrinogen conformation as measured by intrinsic tryptophan fluorescence significantly decreased in the 300 μM SNAP (38 057 ± 1196 mean fluorescence intensity (MFI)) and SNP (368 617 ± 541 MFI) groups versus the NAP control (47 937 ± 1196 MFI). However, infused 1000 ppm NO gas had no direct effect on the ITF after 1 h of incubation at 37 °C. High performance liquid chromatography (HPLC) showed that fibrinogen degradation by 0.03 U ml−1 thrombin was concentration-dependently reduced after 1 h with SNAP but not with NAP or SNP. Western blotting analysis was done on the RSNOs, SNAP and NAP, and the non-RSNO, SNP, incubated fibrinogen solutions and the results showed that the percent level of the Aγ dimer with respect to total Aγ dimer + γ monomer was significantly reduced in the case of the SNAP group when compared to the SNP group. These results suggest that NO donors such as SNAP and SNP induce fibrinogen conformational changes by potentially nitrosating fibrinogen tyrosine residues. These NO-mediated fibrinogen changes induced via NO donors may provide another mechanism of NO for improving thromboresistance in ECCs.

The shelf-life of human platelets preserved in vitro for therapeutic transfusion is limited because of bacterial contamination and platelet storage lesion (PSL). The PSL is the predominant factor and limiting unfavorable interactions between the platelets and the non-biocompatible storage bag surfaces is the key to alleviate PSL. Here we describe a surface modification method for biocompatible platelet storage bags that dramatically extends platelet shelf-life beyond the current US Food and Drug Administration (FDA) standards of 5 days. The surface coating of the bags can be achieved through a simple yet effective dip-coating and light-irradiation method using a biocompatible polymer. The biocompatible polymers with tunable functional groups can be routinely fabricated at any scale and impart super-hydrophilicity and non-fouling capability on commercial hydrophobic platelet storage bags. As critical parameters reflecting the platelets quality, the activation level and binding affinity with von Willebrand factor (VWF) of the platelets stored in the biocompatible platelet bags at 8 days are comparable with those in the commercial bags at 5 days. This technique also demonstrates promise for a wide range of medical and engineering applications requiring biocompatible surfaces. Statement of significance Current standard platelet preservation techniques agitate platelets at room temperature (20–24 °C) inside a hydrophobic (e.g., polyvinyl chloride (PVC)) storage bag, thereby allowing preservation of platelets only for 5 days. A key factor leading to quality loss is the unfavorable interaction between the platelets and the non-biocompatible storage bag surfaces. Here, a surface modification method for biocompatible platelet storage bags has been created to dramatically extend platelet shelf-life beyond the current FDA standards of 5 days. The surface coating of the bags can be achieved via a simple yet effective dip-coating and light-irradiation method using a carboxybetaine polymer. This technique is also applicable to many other applications requiring biocompatible surfaces.

Nitric oxide (NO) is an endogenous vasodilator as well as natural inhibitor of platelet adhesion/activation. Nitric oxide releasing (NOrel) materials can be prepared by doping an NO donor species, such as diazeniumdiolated dibutylhexanediamine (DBHD/N2O2), within a polymer coating. The inherent hemocompatibility properties of the base polymer can also influence the efficiency of such NO release coatings. In this study, four biomedical grade polymers were evaluated in a 4 h rabbit model of thrombogenicity for their effects on extracorporeal circuit thrombus formation and circulating platelet count. At the end of 4 h, Elast-Eon E2As was found to preserve 58% of baseline platelets versus 48, 40, and 47% for PVC/DOS, Tecophilic SP-60D-60, and Tecoflex SG80A, respectively. Elast-Eon also had significantly lower clot area of 5.2 cm2 compared to 6.7, 6.1, and 6.9 cm2 for PVC/DOS, SP-60D-60, and SG80A, respectively. Based on the results obtained for the base polymer comparison study, DBHD/N2O2-doped E2As was evaluated in short-term (4 h) rabbit studies to observe the NO effects on prevention of clotting and preservation of platelet function. Platelet preservation for this optimal NO release formulation was 97% of baseline after 4 h, and clot area was 0.9 cm2 compared to 5.2 cm2 for controls, demonstrating that combining E2As with NO release provides a truly advanced hemocompatible polymer coating for extracorporeal circuits and potentially other blood contacting applications.

The effect of epigallocatechin-3- O-gallate (EGCG), a major component of green tea, on platelet preservation was evaluated. Single donor platelets ( N = 10) were collected and preserved by the standard method. EGCG was added to the platelet concentrates before preservation and then the functional and biochemical parameters were monitored throughout the storage period. After 6 days of preservation, the aggregability of the platelets was significantly maintained by addition of 50 and 100 μg/ml of EGCG. Platelet prothrombinase activity was also significantly retained by the addition of EGCG. The accumulation of P-selectin and RANTES in the plasma preserved with EGCG was less than those preserved without EGCG, which indicated that EGCG might inhibit platelet activation. Furthermore, EGCG reduced the increase of LDH in plasma during preservation and inhibited the activation of caspase-3 and cleavage of gelsolin, thereby showing that EGCG could inhibit the apoptosis of platelets. These results suggest that EGCG may play an effective role in preserving platelets by inhibiting the activation and apoptosis of platelets.

I was born in Halmstad, Sweden, in 1926. I began medical school in Lund and continued in Stockholm where I received an MD degree in 1951. I had training in surgery, internal medicine, clinical bacteriology, transfusion medicine, and blood group serology. I worked at the Karolinska Hospital and State Institute for Blood Group Serology, Stockholm, from 1952 to 1960. I obtained my PhD in immunology, Uppsala University, in 1962. I became the Blood Bank Director at the University Hospital, Uppsala, from 1960 to 1989, and professor and scientific consultant from 1989 onward. My research student at the blood bank, S Gunnar O. Johansson detected the first immunoglobulin E myeloma and characterized immunoglobulin E together with H Bennich. My main scientific interests include improvements of red blood cell and platelet preservation. In clinical transfusion medicine, I contributed to the use of adenine (acid-citrate-dextrose–adenine), additive solutions (saline-adenine-glucose-mannitol and platelet additive solution I), and improved component preparation techniques (“bottom-and-top” technique, Opti System). I was the Secretary General for the 12th Congress of the International Society of Blood Transfusion, Stockholm, 1964. I was a member of the Executive Council of the International Society of Blood Transfusion, and later became the Vice President and President (1969 to 1978). Fellow Royal Society of Sciences, Uppsala. Awards received included the Karl Landsteiner Memorial Award of AABB (1986) and the James Blundell Award of BBTS (1993).

Background We tested whether administration of FK633, a short-acting glycoprotein IIb/IIIa inhibitor, before median sternotomy and cardiopulmonary bypass was able to interrupt the platelet activation loop and thereby preserve platelet number and function. Methods This study investigated 16 pigs that underwent median sternotomy and 120 minutes of normothermic cardiopulmonary bypass (100 mL/kg) adding pericardial blood to the perfusate. FK633 was administered with heparin to one group (group F, n=8), whereas only heparin was administered to the control group (group C, n=8). Blood samples were obtained at several times, and complete blood count, platelet aggregation to adenosine diphosphate, thrombin-antithrombin complex, and bradykinin were evaluated. P-selectin expression and fibrinogen binding on platelet surfaces were measured by flow cytometry. Template bleeding times were measured before and after cardiopulmonary bypass. Chest tube drainage and hematocrit were determined at 2 and 6 hours after cardiopulmonary bypass. Results In group F, platelet counts were preserved from 90 minutes of cardiopulmonary bypass. Platelet aggregation was inhibited at the beginning of cardiopulmonary bypass and showed no change at wound closure, and bleeding times were shortened at 2 hours after cardiopulmonary bypass. There were significant reductions in hematocrit of drainage. Flow cytometry showed no changes in P-selectin expression and fibrinogen binding in group F, whereas P-selectin expression and fibrinogen binding were elevated in group C. Conclusions Platelet inhibition with FK633 before invasive surgical procedure preserved platelet counts during and after cardiopulmonary bypass, and produced normal or near-normal bleeding times in the immediate postoperative period.

Objective: Temporary pharmacologic inhibition of platelet function during and after cardiopulmonary bypass (CPB) (platelet anesthesia) is an attractive strategy for preserving platelets during CPB. We examined the efficacy of FK633, an ultra-short acting glycoprotein IIb/IIIa antagonist. Methods: The study was carried out in six mongrel dogs that received an intravenous bolus of 0.1 mg/kg of FK633 at the time of administration of heparin (group F), and six control dogs (group C). All animals underwent 60 min of normothermic CPB followed by a 2-h observation period. Blood samples for platelet count, platelet aggregation to adenosine diphosphate and parameters concerning the coagulation system were obtained at eight time points. Hemodynamics, bleeding time, and postoperative blood loss were assessed serially. Scanning electron micrograph of the oxygenator's membrane was investigated. Results: FK633 significantly protected platelet number (group F, 59 ± 10% versus group C, 38 ± 15% of the pre-CPB value; P < 0.01), and inhibited platelet aggregation to adenosine diphosphate (group F, 13 ± 12% versus group C, 35 ± 9% of the pre-CPB value; P < 0.01) during CPB. Postoperative blood loss did not significantly differ between the two groups, but there was a tendency of less bleeding in group F (group F, 73 ± 23 ml versus group C, 111 ± 44 ml; P = 0.09). In group F, scanning electron micrograph of the oxygenator's membrane showed that its surface was free from platelets. There were no significant differences between the groups in hemodynamics. Conclusions: An ultra-short acting glycoprotein IIb/IIIa antagonist, FK633, is effective in preventing both platelet aggregation and thrombocytopenia during CPB, and may be effective for minimizing postoperative bleeding.

Poly-2-methoxyethylacrylate (PMEA) is a new coating material, and several studies have revealed that PMEA-coated cardiopulmonary bypass (CPB) circuits have good biocompatibility. This study sought to compare this biocompatibility with those of heparin-coated and noncoated circuits.Forty-five patients undergoing coronary artery bypass grafting were randomly assigned to PMEA-coated (group P, n = 15), heparin-coated (group H, n = 15), or noncoated (group N, n = 15) circuit groups. Clinical data and the following markers were analyzed: (1) platelet preservation by number of platelets; (2) complement (C) activation by C3a and C4a levels; (3) inflammatory response by interleukin-6 (IL-6) and interleukin-8 (IL-8) levels.Platelet numbers were significantly preserved in group P compared with groups N and H. Postoperative blood loss did not differ among the groups. During CPB, C3a values were significantly lower in group H (536 +/- 145 ng/mL) than in group P (1,458 +/- 433 ng/mL, p0.01) and group N (1,815 +/- 845 ng/mL, p0.01). The C4a values did not differ 60 minutes after CPB initiation among the groups. The IL-6 and IL-8 levels were significantly lower in group P and group H than in group N.The PMEA coating was superior to heparin coating and noncoating in preserving platelets, and was equivalent to heparin coating in terms of the perioperative clinical course and inhibition of inflammatory cytokines, but slightly inferior in reducing complement activation.

Serotonin uptake and response to hypotonic shock were studied after storage of platelet-rich plasma for three days at 4, 25, and 37 C. Both properties were best maintained at 25 C. The greatly impaired serotonin uptake and hypotonic shock response of platelets stored for three days at 37 C were partly restored by resuspension of the platelets in fresh autologous plasma. No improvement was found when platelets stored at 4 C were resuspended in fresh autologous plasma. When platelet suspensions were stored for three days at 4, 25, and 37 C under continuous dialysis against plasma, the results obtained at 37 C were even better than those obtained with platelets stored at 25 C. These results indicate that if the accumulation of metabolites in the plasma milieu, which in addition to other changes results in a drop of pH, is prevented, the effective storage time of platelet concentrates can be prolonged. The use of a closed plastic dialysis system, based on the triple-bag transfusion set is suggested.

Background Poly(2-methoxyethylacrylate) (PMEA) is a new coating material, and several experimental studies have revealed excellent biocompatibility of PMEA-coated cardiopulmonary bypass circuits. The clinical utility of the PMEA-coated circuits was compared with that of uncoated circuits, focusing on perioperative inflammatory response. Methods Twenty-two patients were randomized to PMEA-coated (group P; Capiox RX25; n=11) or uncoated (group U; Capiox SX10; n=11) circuit group, and underwent coronary artery bypass grafting and/or valve operations. The following markers, as well as clinical outcomes, were analyzed perioperatively: (a) complement activation by C3a (including C3a-desArg) concentrations; (b) leukocyte activation by polymorphonuclear-elastase concentrations; (c) acute phase inflammatory response by interleukin-6 concentrations; and (d) platelet preservation by number of platelets. Results The maximal values of C3a and polymorphonuclear-elastase were significantly lower in group P than in group U. The intergroup difference of interleukin-6 was not significant. Although preservation of platelets was significantly better in group P until 1 hour after initiating cardiopulmonary bypass, no significant intergroup difference was observed thereafter. The duration of postoperative mechanical ventilation revealed no significant intergroup difference. Conclusions The PMEA-coated circuits exhibited better suppression of perioperative complement and leukocyte activation than the uncoated circuits. In addition, the price of the PMEA-coated circuits is the same as that of the uncoated circuits. Therefore, we judged that the clinical utility of the PMEA-coated circuits is superior to those of the uncoated circuits.

Return of blood activated by tissue factor is the main culprit for triggering the coagulation cascade. When this activated blood is diverted from the cardiopulmonary bypass (CPB) circuit, it becomes possible to evaluate the effect of surface treatment on platelet and complement activation. Twenty adult patients undergoing elective coronary artery bypass grafting (CABG) were randomly assigned either to a control group ( n= 10) or to a group in which the CPB circuit was completely coated with phosphorylcholine ( n= 10). Plasma concentrations of platelet factor 4 (PF4), β-thromboglobulin (βTG), C3, C3d, C4, TCC, thrombin generation, haptoglobin and free haemoglobin, as well as blood loss, were measured. No significant differences between the two groups were found for haemolysis and thrombin generation. The mean total release of PF4 and βTG during CPB was 9338± 17303 IU/ml/CPB and 3790± 4104 IU/ml/CPB in the coated group versus 22192± 13931 IU/ml/CPB ( p= 0.011) and 8040± 3986 IU/ml/CPB ( p= 0.005) in the control group. Blood loss was 30% less in the coated group compared to the control group. Phosphorylcholine coating appears to have a favourable effect on blood platelets, which is most obvious after studying the changes during CPB. Clinically, this effect resulted in a 30% reduction in blood loss.

Blood-material interactions are critical to the success of implantable medical devices that are used in thousands of patients every day. Some common blood-contacting devices include catheters, stents, vascular grafts, heart valve prostheses, and extracorporeal circulation/membrane oxygenation systems. Among other complications, thrombosis and clot formation remains one of the major challenges in clinical application of these devices. The initial biological response of blood to a foreign surface is the rapid adsorption of plasma proteins, which is followed by platelet adhesion and activation, and ultimately thrombus formation. The key factors in clot formation are the chemical and physical nature of the surfaces and their interactions with the blood components, such as platelets and plasma proteins. Despite decades of research, an ideal non-thrombogenic surface is still yet to be identified and clinical use of these blood-contacting devices requires use of anticoagulation agents, increasing the risk of bleeding in patients. In this chapter, we will review some of the current and most promising strategies that have been used over the years to develop polymeric materials with improved hemocompatibility, including highly hydrophilic or hydrophobic surfaces, albumin coated surfaces, zwitterionic polymers, attached endothelial cells, patterned surfaces, immobilized heparin, and nitric oxide (NO) releasing/generating surfaces. We will also discuss some of the important techniques employed (using in vitro and in vivo models) to assess the hemocompatibility of any new material, including the measurement of platelet preservation, platelet and protein adhesion, the effect of flow rates on thrombosis, and the ultimate surface clot area.

Hemocompatibility is the goal for any biomaterial contained in extracorporeal life supporting medical devices. The hallmarks for hemocompatibility include nonthrombogenicity, platelet preservation, and maintained platelet function. Both in vitro and in vivo assays testing for compatibility of the blood/biomaterial interface have been used over the last several decades to ascertain if the biomaterial used in medical tubing and devices will require systemic anticoagulation for viability. Over the last 50 years systemic anticoagulation with heparin has been the gold standard in maintaining effective extracorporeal life supporting. However, the biomaterial that maintains effective ECLS without the use of any systemic anticoagulant has remained elusive. In this review, the in vivo 4-h rabbit thrombogenicity model genesis will be described with emphasis on biomaterials that may require no systemic anticoagulation for extracorporeal life supporting longevity. These novel biomaterials may improve extracorporeal circulation hemocompatibility by preserving near resting physiology of the major blood components, the platelets and monocytes. The rabbit extracorporeal circulation model provides a complete assessment of biomaterial interactions with the intrinsic coagulation players, the circulating platelet and monocytes. This total picture of blood/biomaterial interaction suggests that this rabbit thrombogenicity model could provide a standardization for biomaterial hemocompatibility testing.

Cold-induced platelet aggregation (CIPA) in PRP has previously been documented in connection with platelet preservation (4–15°C). This report describes hypothermia-induced platelet aggregation (HIPA) in whole blood and at temperatures used in open-heart surgery (24–32°C). HIPA (specifically, the formation of occlusive aggregates) was studied in human whole blood. Fresh heparinized (1.5 U/ml) human blood was cooled and maintained at target temperatures (15, 20, 24, 28, 32, or 37°C) as it flowed (1 ml/min) through 75-cm long 1/32″ internal diameter polymer conduit. The formation of aggregates in the tubing was verified using optical video microscopy and was quantified by a light-scattering method and a constant-pressure filtration method. Donors were tested at least twice at each target temperature and were classified into three separate response regimes (Low, Medium, and High) on the basis of the number of aggregates and the duration of their appearance. The screening of 121 donors (average age 22.3 ± 4.3 years) for HIPA at 24°C (the temperature of maximum response) indicated 14% High Responders, 18% Medium Responders, and 68% Low Responders. HIPA was inhibited by EDTA, citrate, PGE1, and Tirofiban, but not by aspirin, and it was enhanced by elevated heparin levels. HIPA was consistently noted in the blood of a subpopulation of donors, and the associated platelet aggregates in the blood of High Responders were rigid and occlusive. It is postulated that such aggregates may contribute to cognitive dysfunction noted in patients undergoing hypothermic open-heart surgery, and that postulus is being investigated. Am. J. Hematol. 69:45–55, 2002. © 2002 Wiley-Liss, Inc.

BACKGROUND The platelet storage lesion is characterized metabolically by a pH decrease associated with lactic acid generation; a change in platelet morphology from discoid to spherical; a diminished response to in vitro challenge tests, such as the hypotonic shock response (HSR) and extent of shape change (ESC); increased surface P-selectin expression; and decreased in vivo recovery and survival. Altering storage conditions to improve these measures could allow for extension of the duration of in vitro storage. STUDY DESIGN AND METHODS ABO-identical paired platelet concentrates were pooled and then equally divided into two plastic bags. Either L-carnitine (LC) or an equal volume of saline (control) was added to one container of each pair. Platelets were stored at 20 to 24 degrees C for 5 to 10 days or at 1 to 6 degrees C for 5 days at various concentrations of LC between 0.1 and 15 mM: At the end of storage, pH, glucose consumption, lactate generation, HSR, ESC, and surface P-selectin expression were measured. In different experiments, paired platelet concentrates were spiked with a Staphylococcus epidermidis suspension in the presence and absence of L-carnitine at a concentration of 5 mM: RESULTS At 20 to 24 degrees C and concentrations of LC between 0.1 and 5 mM:, there was evidence of better pH preservation, less glucose consumption, and less lactate generation. Only with storage beyond 5 days was a difference present in either surface P-selectin expression or HSR. An L-carnitine concentration of 5 mM: appeared optimal. L-carnitine did not enhance the growth of bacteria after 7 to 8 days of storage. CONCLUSION LC at 5 mM: may improve the quality of platelet concentrates that are stored beyond 5 days. There was no indication that LC at this concentration would promote bacterial growth. It may be a useful additive to platelet preservation.

Aprotinin administration with or without a heparin-coated circuit is expected to modulate subclinical plasma coagulation and fibrinolysis and platelet function during cardiopulmonary bypass. We studied the effect of the application of both, either one, or neither of an aprotinin prime (100 million KIU) and heparin-coated circuit in 32 consecutive patients undergoing coronary artery bypass surgery randomly divided into four groups of 8 patients each. Aprotinin was not used with the non-heparin-coated circuit in the control group. Levels of fibrinopeptide A were significantly lower in the heparin-coated circuit groups (P

Using the current blood bank storage conditions at 22 degrees C, the viability and function of human platelets can be maintained for only 5 days. This does not allow for the necessary and extensive banking of platelets needed to treat patients afflicted with thrombocytopenia, a side effect of many invasive surgeries such as cardiopulmonary bypass or bone marrow transplantation. The development of optimal techniques for long-term cryopreservation and banking of human platelets would provide the ability to greatly extend the viable life of the platelet and would fulfill an increasing and urgent need in many clinical applications. To determine the optimal techniques for platelet preservation, the expression of an activation marker, phosphatidylserine, on the platelet membrane during storage at 22 and 8 degrees C as well as during the different freezing preservation processes was examined using flow cytometry and annexin V binding assay. Human platelets were identified by both CD41 and light scatter in flow cytometry. In cryopreservation experiments, effects of the following factors on platelet activation were evaluated: (a) cryoprotective agents (CPAs) type: dimethyl sulfoxide (Me2SO), ethylene glycol (EG), and propylene glycol (PG), (b) CPA concentration ranging from 0 to 3 M, and (c) ending temperatures of a slow cooling process at -1 degrees C/min. Our results demonstrated that (a) approximately 50% of platelets were activated on days 7 and 16 at 22 and 8 degrees C, respectively; (b) platelets were not significantly activated after 30-min exposure to 1 M Me2SO, EG, and PG at 22 degrees C, respectively, and (c) there was a significant difference in cryoprotective efficacy among these three CPAs in preventing platelets from cryoinjury. After being cooled to -10 degrees C, 74% of the cryopreserved platelets survived (nonactivated) in 1 M Me2SO solution, while in 1 M EG and 1 M PG solutions, 62 and 42% of the platelets survived, respectively. Using the information that Me2SO consistently yields higher percentages of nonactivated platelets and does not seem to be cytotoxic to platelets for 30-min exposure time, this was found to be the optimal cryoprotective agent for platelets. In addition, significant Me2SO toxicity to platelets was not noted until Me2SO concentrations exceeded 2 M. Finally, a concentration of 1 M Me2SO proved to be the most effective at all cryopreservation ending temperatures tested (-10, -30, -60, and -196 degrees C). In conclusion, under the present experimental conditions, a storage temperature of 8 degrees C appeared to be much better than 22 degrees C. Although the potential chemical toxicity of 1 M Me2SO, EG, or PG is negligible, 1 M Me2SO was found to be optimum for cryopreservation of human platelets. PG has the least cryoprotective function for low-temperature platelet survival.

Perioperative aprotinin decreases postoperative blood loss in adults undergoing cardiac operations, but its role is less clear in children. Therefore, a trial of aprotinin in pediatric cardiac operations was conducted to study the efficacy of its use in children.Forty-two patients were randomly assigned to receive either high-dose aprotinin or placebo. Aprotinin efficacy was assessed using time from protamine administration to skin closure, postoperative blood loss and hemoglobin loss, and postoperative transfusion requirements. Measures of fibrinolysis (fibrin degradation product titers) and platelet preservation (beta-thromboglobulin levels) were also assessed.There were no statistically significant differences between groups in any of the blood loss or transfusion parameters. Fibrin degradation product levels, measured 4 hours postoperatively, had increased significantly for control patients, but remained unchanged for the aprotinin group (p0.02). beta-Thromboglobulin levels increased more rapidly during cardiopulmonary bypass in the control group (p = 0.03).Aprotinin appears to provide no clinical benefit in routine pediatric cardiac operations. A reduction in fibrinolysis, with perhaps an early preservation of platelet structure, is seen in the aprotinin group.

Cytokines are implicated in the pathogenesis of the "whole-body inflammatory response" that may complicate the period after cardiopulmonary bypass (CPB). Low-Dose aprotinin in the pump during CPB has been shown to improve postoperative hemostasis and platelet preservation. We tested the hypothesis that low-dose aprotinin influences the inflammatory reaction (in terms of cytokine release) after CPB.In a prospective, randomized study, 36 patients undergoing elective coronary artery bypass grafting were investigated. Nineteen patients received low-dose aprotinin (2 x 10(6) KIU (280 mg] in the pump), and a control group of 19 did not. Complement activation, cytokine production, leukocyte elastase release. D-dimer level, full blood count, postoperative blood loss, and transfusion requirements were analyzed before, during, and after after CPB.Interleukin-1 beta was not detected in either group, whereas traces of tumor necrosis factor-alpha were infrequently observed. Plasma elastase, interleukin-6, interleukin-8, and neutrophil count increased (p0.001) during and after CPB compared with the baseline levels, reaching a peak at 2 hours after protamine administration in both groups before returning toward baseline at 24 hours. Proinflammatory cytokine markers did not differ significantly (p0.1) between the groups throughout the study period. The C5b-9 level increased (p0.001) in both groups perioperatively, reaching its peak 15 minutes after protamine. Twenty-four-hour postoperative blood loss was significantly (p0.001) reduced in the aprotinin group in association with markedly reduced D-dimer levels (p0.001). Patients in the aprotinin group also received significantly less banked blood postoperatively than the control group (p0.01).Low-dose aprotinin fails to modify proinflammatory cytokine release, yet confers hemostatic improvement through reduced fibrinolysis in patients undergoing routine coronary artery bypass grafting.

Development of increasingly complex perfusion devices with bonded heparin allowed for significant improvement of thromboresistance of most basic components required for cardiopulmonary bypass. In his recent review of heparin-coated cardiopulmonary bypass circuits, Gravlee cited 91 references dealing with heparin-coated surfaces, and far more can be found if the search includes material technology or heparin-coated devices not designed for cardiopulmonary bypass (eg, ventricular assist devices, hemofilters, catheters). The present review is focused on long-term application of heparin-coated equipment in conjunction with basic work on heparin bonding relevant for extracorporeal membrane oxygenation. Experimental open chest cardiopulmonary bypass using heparin-coated equipment without systemic heparinization up to 36 hours has shown improved thromboresistance, and better platelet preservation was demonstrated for perfusion with heparin-coated cardiopulmonary bypass equipment up to 5 days in the experimental set-up. Similar findings were reported for roller pump perfusion with heparin-coated tubing and centrifugal pump perfusion with heparin-coated pump heads. More recently, heparin bonding was also made available for oxygenators with true membranes that preclude plasma leakage. The available knowledge on clinical applications of heparin-coated perfusion equipment is mainly based on short-term applications like ours, which now includes more than 300 patients. Reduced postoperative blood loss and as a result fewer transfusions were the main benefits of heparin-coated equipment allowing for perfusion with low systemic heparinization. There are only a few reports on long-term use of heparin-coated equipment for prolonged circulatory support. However, the longest clinical application of a single device is that of an intravascular gas exchanger that remained fully functional during a 29-day implantation period. Finally, it appears, that circulating protamine interacts with surface-bound heparin. Protamine administration should therefore be avoided during perfusion with heparin-bonded equipment to maintain the improved thromboresistance.

A best-evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was ‘Is a fully heparin bonded cardiopulmonary bypass circuit superior to a standard cardiopulmonary bypass circuit?’ Altogether more than 792 papers were found using the reported search, of which 13 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated (Table 1). The studies analysed show that perfusion with heparin-coated and heparin-polymer-coated bypass does not increase the risk of adverse effects but reduces blood loss, re-operation rates, ventilation time, length of intensive care unit (ICU) and hospital stay and is also associated with improved biocompatibility, as evidenced by platelet preservation, reduced leucocyte and complement activation, and proinflammatory cytokine production. The various coated circuits have comparable biocompatibility as evaluated by a range of inflammatory markers and clinical outcomes. Three studies documented a significant decrease in post-operative blood loss (P = 0.001–0.54) and a meta-analysis found that perfusion with a heparin-bonded circuit resulted in a reduction in blood transfusion requirements (20%), ventilation time (P 250) resulted in the greatest clinical benefit and improvement in inflammation. One study documented significant platelet preservation with the use of third-generation heparin-polymer-bonded circuits (P ≤ 0.05). We conclude that despite heparin-bonded and newer third-generation heparin-polymer-bonded cardiopulmonary bypass circuits having a greater cost per person, their improved clinical outcomes and biocompatibility in patients undergoing cardiac surgery make them a preferable option to standard non-heparin-bonded circuits.

Background: Two types of surface coating for cardiopulmonary bypass (CPB) are used: bioactive (heparin, nitric oxide) and biopassive (albumin, polyethyleneoxide (PEO), phosphorylcholine). When haemocompatible coatings are combined with the separation of pleuro-pericardial aspiration, attenuation of both the coagulation and complement cascades, as well as better platelet preservation, has been demonstrated. This study wants to investigate if the combination of a bioactive with a biopassive coating (unfractionated heparin embedded in a phosphorylcholine matrix) combines the beneficial effects of both approaches. Materials and methods: Thirty patients undergoing elective CABG were prospectively randomized into two groups of 15 patients. The sole exclusion criterion was an ejection fraction of less than 40%. In the control group (PC), the whole CPB circuit was coated with phosphorylcholine (PC). In the study group (XPC), unfractionated heparin was embedded in the PC matrix of the oxygenator and arterial line filter. Results: No differences were found for haemolytic index, thrombin-anti-thrombin complex (TAT), IL-6, IL-10 and blood loss. PF4 plasma concentration increased from 27.6±22.0 IU/mL to 165.7±43.9 IU/mL (p Conclusions: Based on our results, there is no additional benefit in combining phosphorylcholine with unfractionated heparin in elective patients undergoing coronary artery bypass grafting (CABG). Massive haemodilution leads to enhanced complement activation.

Platelet storage lesion (PSL), correlating with reduced in vivo recovery/survival and hemostatic capacity after transfusion, is characterized essentially by morphological and molecular evidence of platelet activation and energy consumption in the medium. Processes that limit shelf-life are multifactorial, and include both necrosis and apoptosis. PSL is greatly influenced by factors including duration of storage, temperature, ratio of platelet number to media volume, solution composition with respect to energy content and buffering capacity, and gas permeability of the container. Recent progress for slowing PSL has been made with storage media that more effectively fuel ATP production and buffer the inevitable effects of metabolism. Improved oxygen-permeability of containers also helps to maintain aerobic-dominant glycolysis. Patients stand to benefit from platelet products of higher intrinsic quality that store well until the moment of transfusion.

Recent attention to solutions that replace most or all plasma in platelet concentrates, while maintaining satisfactory platelet function, is motivated by the potential of plasma reduction or depletion to mitigate various transfusion-related adverse events. This report considers the electrolytic composition of previously described platelet additive solutions, in order to draw general conclusions about what is required for platelet function and longevity. The optimal concentrations of Na(+) and Cl(-) are 69-115 mM. The presence of both K(+) and Mg(2+) in platelet suspension at nearly physiological concentrations (3-5mM and 1.5-3mM, respectively) is indispensable for good preservation capacity because both electrolytes are required to prevent platelet activation. In contrast to K(+) and Mg(2+), Ca(2+) may not be important because no free Ca(2+) is available in M-sol, which showed excellent platelet preservation capacity at less than 5% plasma concentration. The importance of bicarbonate (approximately 40 mM) can be recognized when the platelets are suspended in additive solution under less than 5% residual plasma concentration.

Sixty-three patients admitted for routine coronary bypass operations were randomized to cardiopulmonary bypass (CPB) with a membrane oxygenator (Capiox- CA) or a bubbler (Polystan or William Harvey- WH), and in the Polystan group to prime with or without albumin (P+ or P-). Platelets were counted and blood loss from the mediastinal drains during the first 12 postoperative hours was measured. The reduction in platelet numbers from baseline to closure of the sternum was significantly larger in the P- group (121 x 109/l, median) than in the CA group (55 x 109/l) (p 9/l) and WH (90 x 109/l) groups. The reduced platelet loss in the P+ group compared with P- was accompanied by a significant reduction in early postoperative chest tube drainage (480 versus 728 ml). Thus, precirculation of the CPB circuit with prime containing a low dose of albumin was a simple and inexpensive means of increasing platelet function with a bubble oxygenator.

Excessive hemorrhage secondary to cardiopulmonary bypass may be encountered after pediatric cardiac operations. Platelet dysfunction appears to be especially responsible for this problem. The proteinase inhibitor aprotinin is suggested to possess platelet preservation properties and reduce blood loss in this situation. The effects of aprotinin (25,000 U/kg after induction of anesthesia, 25,000 U/kg added to the prime, 25,000 U/kg every hour of cardiopulmonary bypass) on platelet function were randomly studied in 12 children with a weight of less than 10 kg (group 2) and 12 children weighing more than 10 kg (group 4), who were compared with two groups of children without aprotinin (group 1,10 kg; group 3,10 kg). Twelve children undergoing major vessel operations without cardiopulmonary bypass and aprotinin served as a control. Platelet function was assessed using aggregometry (turbidometric technique with adenosine diphosphate, 2.0 mumol/L; collagen, 4 micrograms/mL; epinephrine, 25 mumol/L; NaCl [control]). Platelet function was not altered in the control patients within the entire investigation period. Maximum aggregation in the small children was already lower at baseline in comparison with that of the children10 kg. Cardiopulmonary bypass was followed by a significant reduction in platelet aggregation in all groups. Treatment with aprotinin did not improve platelet function (maximum aggregation and maximum gradient of aggregation) in any group. On the first postoperative day, maximum aggregation in the small children exceeded baseline values, whereas in both groups of children10 kg baseline values had almost been established. Postoperative blood loss was not reduced by treatment with aprotinin.(ABSTRACT TRUNCATED AT 250 WORDS)

We have used recently developed flow cytometric techniques in combination with specific monoclonal antibodies (MoAbs): (i) to study the membrane expression of two major platelet glyco-protein (GP) complexes, GP Ib-IX and GP IIb-IIIa, and the appearance of activation-dependent membrane epitopes, and (ii) to evaluate the relative proportion of platelet-derived microparticles and their GP pattern during storage of platelet-rich plasma. Binding of fluoresceinated (FITC) LJ-P3, an anti-GP Ibalpha MoAb, to platelets continuously decreased by 50% during storage for 6 days. Binding of FITC-LJ-P4, directed to the GP IIb-IIIa complex on the platelet surface, also decreased during day 1-3, but increased again to baseline levels from day 4-6 of storage. The re-increase of GP IIb-IIIa was associated with the exposure of secretion-dependent granule membrane proteins, GMP-140 and GP-53, and the presence of thrombospondin at the platelet surface. These neoantigens are indicative of platelet activation. Moreover, the proportion of platelet-derived microparticles increased from 6 to 22% (p less than 0.001), whereby a predominant subpopulation of GP Ib-negative microparticles was identified. Thus, significant changes in platelet membrane GP occur during standard platelet preservation. These changes, resulting from time-dependent platelet activation and/or proteolysis in vitro may affect platelet GP receptor function upon transfusion.

The influence of additional hirudin in low doses on platelet and coagulation parameters was studied in platelet concentrates (PC) prepared by cytapheresis using citrate-dextrose solution formula A. The in vitro release of platelet factor 4 and β-thromboglobulin was markedly lowered and morphological platelet alterations, as assessed by platelet size studies were considerably less accentuated in the presence of hirudin over a 5-day storage period; this suggests a possibly protecting effect on platelet function. No clear activation of the coagulation and fibrinolysis system was evident during PC storage with and without hirudin since thrombin-antithrombin III complexes and D-dimers did not markedly change.

On LabVIEW, a temperature measurement and control system for constant temperature reciprocator platelet preservation box is designed based on Fuzzy-PID control. For temperature measurement part, we use multi-sensor data fusion algorithm to optimization data, and output fault early warming signal for sensors; Using Fuzzy-PID control algorithm to control the system, that will make the system has good dynamic characteristics, and has more ideal steady-state quality; Using LabVIEW software developing the temperature measurement and control system, that will make the measurement and control charts real-time display; Real-time state monitoring functions guarantee system security operation. And compared with traditional design method, using virtual technology allows the system to operation simply, to set up or reconstruct easily, and users can customize equipment function based on actual requirement.

Despite advances in the safety, processing, and storage of conventional 22°C liquid-stored allogeneic platelet concentrates (see Chapter 69), there are still significant limitations to standard platelet concentrates (Table 70-1). These limitations have led to efforts to minimize the exposure of recipients to allogeneic blood products and to develop safe and effective platelet products and substitutes with longer shelflives. This chapter reviews advances in the development of new platelet products, synthetic platelet substitutes, new storage methods, and novel pathogen inactivation technology for platelet concentrates.

Low-dose aprotinin in the pump during cardiopulmonary bypass (CPB) has been shown to improve postoperative hemostasis and platelet preservation. This investigation was undertaken to evaluate the effects of mini-dose pump prime only aprotinin (70 mg) on the hemostatic parameters and blood transfusion requirements in patients undergoing on-pump coronary artery bypass surgery (CABG).We studied 86 patients who underwent CABG. Forty patients received mini-dose aprotinin (500.000 KIU [70 mg] in the pump), and a control group of 46 did not. D-dimer level, full blood count, postoperative blood loss, and transfusion requirements were analyzed before, after one hour operation and first day after operation.Twenty-four-hour postoperative blood loss was significantly reduced in the aprotinin group (188+/- 51.5 ml vs. 818+/- 243.5 ml, [mean +/- standard deviation] p0.01). Patients in the aprotinin group also received significantly less banked blood posoperatively than the control group (1.20 +/- 0.52 vs. 3.33 +/- 1.13 Units/per patient (p0.04). One hour after operation, and 24 hours after operation D-dimer level was significantly reduced in the aprotinin group (p0.008 and p0.017, respectively).Mini dose pump-prime aprotinin reduces postoperative blood loss, transfusion requirements and yet confers hemostatic improvement through reduced fibrinolysis in patients undergoing routine coronary artery bypass grafting.

Background . Donor plasma proteins are associated with non-hemolytic allergic reactions, such as urticaria or laryngeal edema, in platelet-transfusion recipients. Replacement of plasma with synthetic media from platelet concentrates (PCs) is considered to be effective in preventing such reactions. However, platelets preserved in media depleted of less than 10% plasma are reported to have functions inferior to those preserved in plasma. Methods . Fukushima Cocktails (FCs) contain glycerol (25, 50 or 100 mM), sodium acetate, glucose and other components. To test the effect and determine the most suitable concentration of glycerol for platelet preservation, functions of platelets including aggregation, hypotonic shock response and swirling pattern and released biochemicals were measured with platelets preserved in Fukushima Cocktails. The effects of residual plasma on platelet functions were also evaluated. Autologous platelets stored for 3 days in solution containing 50 mM glycerol were transfused into healthy volunteer donors to evaluate their safety and survival. Results . The functions (aggregation and hypotonic shock response) of platelets preserved in Fukushima Cocktails with 10% residual plasma were preserved for 5–7 days as well as plasma controls, whereas platelets stored for 9 days in a medium lacking glycerol became swollen and β-thromboglobulin and thromboxane B 2 increased. When the residual plasma was more than 5%, platelet functions including aggregation, hypotonic shock response and swirling pattern were well preserved for 7 days. The in vivo platelet survival rates at 24 and 48 h after transfusion of platelets stored for 3 days in Fukushima Cocktail were 77% and 60%, respectively, which were not less than autologous plasma-stored platelets. Conclusion . Glycerol at a concentration of around 50 mM has a beneficial effect on platelet preservation for more than 7 days. The results of these experiments indicate that platelets stored in Fukushima Cocktail should be useful clinically.

To decrease the complications associated with cardiopulmonary bypass, novel biomaterials have been introduced that may be less thrombogenic than standard synthetic surfaces.Thirty-four patients undergoing coronary artery bypass grafting were randomized to bypass using either a control circuit or a circuit prepared "tip-to-tip" with a triblock-copolymer (polycaprolactone-polydimethylsiloxane-polycaprolactone).There was a progressive increase in thrombin generation in the control group during bypass, which was not seen in the test group. The test surface decreased the release of tissue plasminogen activator and plasmin-alpha2-antiplasmin complex formation (p0.005). There was also an increased platelet count and a decreased platelet activation in the test group, as detected by GMP-140 expression and beta-thromboglobulin release (p = 0.017). There was also significantly more debris that accumulated on the arterial filter in the control group, as confirmed by scanning electron microscopy.This clinical trial has demonstrated a significant difference in the hematologic effects of the test circuits, with evidence of platelet preservation, decreased fibrinolysis, and decreased thrombin generation. A larger trial would be necessary to establish the clinical relevance of these differences.

Background . The deleterious effects of cardiopulmonary bypass are greater in pediatric patients than in adults. The use of aprotinin to manipulate hemostasis has become an important factor in attempts to reduce adverse consequences of these effects. Methods . This article reviews the literature on the use of aprotinin in pediatric cardiac surgery. Results . Available studies have many deficiencies, often including lack of placebo control, nonhomogeneous populations and procedures, and absence of information on aprotinin plasma concentrations. Comparison of trial results is further complicated by differences in dose regimens, heparin-protamine protocols, and priming. Conclusions . Further trials are required to adequately assess aprotinin effect on platelet preservation, particularly in neonates, to evaluate aprotinin's antiinflammatory action, and to determine optimum dosages to achieve specific objectives. Aprotinin in pediatric cardiac surgery has been found to be associated with no adverse effects, to decrease fibrinolytic and probably platelet activation, and to offer important clinical benefits in specific groups of patients.