Preoperative autologous plateletpheresis in patients undergoing open heart surgery

Blood conservation is an important aspect of care provided to the patients undergoing cardiac operations with cardiopulmonary bypass (CPB). It is even more important in patients with anticipated prolonged CPB, redo cardiac surgery, patients having negative blood group and in patients undergoing emergency cardiac surgery. In prolonged CPB the blood is subjected to more destruction of important coagulation factors, in redo surgery the separation of adhesions leads to increased bleeding and difficulty in achieving the haemostasis and in patients with negative blood group and emergency operations, the availability of sufficient blood can be a problem. Harvesting the autologous platelet rich plasma (PRP) can be a useful method of blood conservation in these patients. The above four categories of patients were prospectively studied, using either autologous whole blood donation or autologous platelet rich plasma (PRP) harvest in the immediate pre-bypass period. Forty two patients were included in the study and randomly divided into two equal groups of 21 each, control group (Group I) in which one unit of whole blood was withdrawn, and PRP group (Group II) where autologous plateletpheresis was utilised. After reversal of heparin, autologous whole blood was transfused in the control group and autologous PRP was transfused in the PRP group. The chest tube drainage and the requirement of homologous blood and blood products were recorded. Average PRP harvest was 643.33 +/- 133.51 mL in PRP group and the mean whole blood donation was 333.75 +/- 79.58 mL in the control group. Demographic, preoperative and intra operative data showed no statistically significant differences between the two groups. The PRP group patients drained 26.44% less (p<0.001) and required 38.5% less homologous blood and blood products (p<0.05), in the postoperative period. Haemoglobin levels on day zero (day of operation) and day three were statistically not different between the two groups. We conclude that autologous plateletpheresis is a better method of blood conservation in terms of better haemostasis, and less requirement of blood and blood products in the postoperative period as compared with the autologous whole blood donation. This technique can be especially useful in the above-mentioned categories of patients.     

The effect of aprotinin on activated protein C-mediated downregulation of endogenous thrombin generation

Thrombin plays a central role in coagulation and haemostasis. Binding of thrombin to thrombomodulin generates activated protein C (APC), which exerts a negative feedback on thrombin formation. Aprotinin, a natural proteinase inhibitor is used extensively during cardiac surgery because this procedure is often associated with profound activation of coagulation and inflammatory pathways. Some in vitro evidences suggest that aprotinin inhibits APC, but the clinical relevance is unclear. The recombinant human soluble thrombomodulin (rhsTM)-modified thrombin generation (TG) assay was used to investigate the effects of aprotinin on APC in plasma samples obtained from healthy volunteers, aprotinin-treated cardiac surgical patients and in protein C (PC)-depleted plasma. Based on the results of in vitro TG assay, addition of rhsTM (0.75-3.0 microg/ml) to volunteer or patient platelet-poor plasma significantly reduced (70.8 +/- 21.9 and 95.3% +/- 4.6%, respectively) thrombin formation when compared with PC-depleted plasma (8.3% +/- 5.2%). Aprotinin (100-200 KIU) caused a small, statistically insignificant decrease in the peak thrombin formation in normal and PC-deficient plasma (12.0 +/- 6.1%). In cardiac surgical patients, levels of functional PC, factor II, antithrombin and platelet significantly decreased after cardiopulmonary bypass (CPB). Soluble thrombomodulin concentrations were increased after CPB (3.5 +/- 2.2 to 5.0 +/- 2.2 ng/ml), but they were still within the normal range for human plasma. Our results showed that, even though endogenous PC level is decreased after CPB, it retains its activity in the presence of thrombomodulin, and aprotinin has limited inhibitory effect on APC generation.     

Combination of autologous Transfusion and Retrograde Autologous Priming Decreases Blood Requirements

In a prospective study, 60 patients posted for coronary artery bypass graft (CABG) surgery on cardiopulmonary bypass (CPB) were assigned to 2 groups of 30 each. (group A =combination of acute normovolaemic haemodilution (ANH) and retrograde autologous priming (RAP), group B=control). The aim was to investigate whether retrograde autologous priming reduces haemoditution as compared to control cases. Patients who had a history of previous cardiac surgery and patients with severe left ventricular dysfunction, were excluded. Group A patients were subjected to pre-CPB intraoperative autologous blood collection prior to heparin administration. Heparin was given (300IU/Kg) and the aorta was cannulated. In addition, prior to bypass, if the patients had a systolic BP>100 mm Hg, 300cc of their blood was withdrawn in a retrograde manner via aortic cannula into the CPB circuit up to the arterial filter, while the 'displaced' asanguinous prime was diverted into a transfer bag. The total bank blood (whole blood) used intra-op was 26 units in the study group [mean 0.86 unit per patient] versus 52 units in the control group (mean 1.73 units per patient) (P<0.001). Blood components and products were not used in this study. The average fall in haematocrit (Hct) on CPB was 27.03% in the study group versus 39.5% in the control group (P < 0.001). Thus retrograde autologous griming in combination with autologus transfusion significantly reduces the need for bank blood.     

Reduction of homologous blood requirement in cardiac surgery by intraoperative aprotinin application--clinical experience in 152 cardiac surgical patients

The protease inhibitor aprotinin interacts with plasmin and kallikrein, which are generated in cardiac surgery during cardiopulmonary bypass (CPB). The influence of high-dose aprotinin application (2 million kallikrein inactivator units given i.v. at the beginning of anaesthesia followed by a 500,000 KIU/h infusion throughout the operation and additional 2 millions KIU added to the priming of the oxygenator) on perioperative blood loss and donor blood requirement was studied in 152 adult cardiac surgical patients. This group was compared to 317 patients having cardiac surgery without the application of aprotinin. Aprotinin reduced the homologous blood requirement by 43% (1783 +/- 100 vs 1015 +/- 131 ml, p less than 0.05), while the reduction of postoperative blood loss was 29% (1070 +/- 43 vs 761 +/- 51 ml, p less than 0.05). Fortytwo percent of the aprotinin treated patients completed their hospital stay without having any donor blood transfusion compared to 18% in the group without aprotinin. The blood saving effect was even more pronounced in operations with prolonged perfusion times. Intra- and postoperative complications were equally distributed in both groups. The blood-saving effect of aprotinin may be due to a platelet-preserving effect and/or kallikrein inhibition during CPB. There were no clinically relevant side effects related to aprotinin observed. It is concluded that high dose aprotinin therapy reduces both postoperative blood loss and homologous blood requirement, and therefore the routine application of aprotinin during cardiac surgical procedures is to be recommended.     

Quality of harvested autologous platelets compared with stored donor platelets for use after cardiopulmonary bypass procedures

Platelet dysfunction has a major contribution in bleeding after cardiopulmonary bypass (CPB) and transfusion of platelets is frequently used to secure haemostasis. Allogeneic platelets prepared for transfusion are functionally impaired. Autologous platelets harvested preoperatively require a shorter storage time before transfusion and their use also avoids the risks associated with transfusion of allogeneic blood products. For the first time, we have compared the functional quality of autologous platelets with allogeneic platelets prepared by two methods, immediately before infusion. Platelet activation was assessed by P-selectin expression and fibrinogen binding using flow cytometry. We also monitored the effects of CPB surgery and re-infusion of autologous platelets on platelet function. Autologous platelet-rich plasma (PRP) contained a significantly lower (P < 0.05) percentage of P-selectin-positive and fibrinogen-positive platelets compared with allogeneic platelet preparations, and also contained a significantly higher (P < 0.05) percentage of responsive platelets. Allogeneic platelets prepared by donor apheresis were more activated and less responsive than those produced by centrifugation of whole blood. In patients' blood, the percentage of platelets expressing P-selectin or binding fibrinogen increased significantly after CPB (P < 0.05), while the percentage of platelets responsive to in vitro agonists was decreased (P < 0.05 in autologous transfusion patients), consistent with platelet activation during the procedure. The percentage of activated platelets decreased (statistically not significant) after re-infusion of autologous PRP. P-selectin expression had returned to pre-CPB levels 24 h post-operatively. Autologous platelet preparations display minimal activation, but remain responsive. Conservation of platelet function may contribute to the potential clinical benefits of autologous transfusion in cardiopulmonary bypass.     

Effectiveness of preoperatively obtained autologous platelet concentrates in open heart surgery

BACKGROUND: Autologous blood components have been widely introduced in open heart surgery. However, the effectiveness of autologous platelet products remains controversial. METHODS: Autologous platelet concentrates (PC) were collected from patients (n = 35) scheduled for primary valvular heart surgery 1 to 3 days before the operation and were transfused immediately after cardiopulmonary bypass. Blood loss and platelet-related factors were compared with the control patients who had no PC (n=35). RESULTS: There were no serious complications in harvesting, preservation, and transfusion of autologous PC. The maximal platelet aggregation response significantly improved after its transfusion and tended to be higher with autologous PC stored 1 day than with ones stored 2-3 days. Activation of coagulation and fibrinolytic factors did not significantly differ between the groups. Postoperative blood loss was significantly less in autologous PC group, and seemed to have a negative correlation with platelet aggregation response. CONCLUSIONS: Autologous PC can be safely prepared and are clinically effective in reduction of postoperative blood loss in open heart surgery.     

Platelet concentrates produced from whole blood using the Atreus processing system

Background  The Atreus 2C+ system automates whole blood (WB) processing into a red cell concentrate, plasma and buffy coat (BC) suitable for platelet concentrate (PC) manufacture. This study compared the quality of PC made from BC using the Atreus, with those made by a manual method.
Study design and methods  WB was collected into Atreus disposables or standard bottom and top processing packs and held without active cooling for 26 h at 22 ± 2°C before processing, either with the Atreus, or using a centrifuge and press. BC were rested for 3 h and then 4 BC were pooled with one unit of plasma, mixed, centrifuged and pressed to make a pooled PC. The PC were analysed for quality markers to day 9 of storage.
Results  Platelet quality was good in both Atreus 2C+ derived PC and control units throughout storage. Metabolic markers (pH, ATP and HSR) and activation markers (CD62P, sCD62P, annexin V binding, microparticles, GP IIb/IIIa) did not differ between the Atreus and control units. Atreus-derived PC had significantly lower platelet yields (302 ± 59 × 10⁹ platelets/unit; mean ± standard deviation, n  = 8) than control PC (411 ± 76 × 10⁹ platelets/unit; P  < 0·01), but met the UK guidelines for platelet yield
Conclusion  From these in vitro data, PC produced from buffy coats prepared using the Atreus appear suitable for clinical use, and WB may be held at ambient temperature overnight without the use of active cooling devices. Optimizing the secondary processing conditions to handle Atreus 2C+ derived BC may increase the platelet yield.     

Whole blood coagulation in children with thrombocytopenia and the response to platelet replacement, recombinant factor VIIa, and a potent factor VIIa analogue

The present study evaluated dynamic coagulation profiles, platelet aggregation, and thrombin generation in whole blood (WB) from eight children with thrombocytopenia during chemotherapy, and the haemostatic potential of platelets (+60 × 10⁹/l), recombinant factor VIIa (rFVIIa – NovoSeven^®), and a potent rFVIIa analogue (NN1731) both at 1 and 4 μg/ml. Dynamic WB coagulation profiles were recorded by thrombelastometry employing activation with tissue factor (TF – Innovin^®) at low concentrations. The baseline WB coagulation patterns were characterised by a prolonged clotting time (CT) and a pronounced reduction in clot propagation (MaxVel). WB platelet aggregation signal was five times lower in the study group compared with measurements in modelled thrombocytopenic WB from healthy volunteers. In vitro addition of fresh platelets reversed the coagulopathy. Addition of rFVIIa induced no significant changes in the thrombelastographic profile, whereas spiking with NN1731 shortened the CT significantly. The changes in WB thrombin generation reflected the changes in the MaxVel. In modeled thrombocytopenic WB from healthy individuals, both rFVIIa and NN1731 exhibited a pronounced haemostatic effect with NN1731 showing greater potency than rFVIIa. Compromised platelet function in the study group was assumingly responsible for the weakened haemostatic potential of rFVIIa as well as that of NN1731.     

Fibrinolytic activity and bleeding after cardiac surgery with cardiopulmonary bypass and low-dose aprotinin therapy.

Low-dose aprotinin inhibits hyperfibrinolysis in cardiac surgery. However, excessive postoperative bleeding and increased fibrinolysis may occur despite low dose-aprotinin administration. We investigated (i) whether fibrinolytic activity significantly rises under low-dose aprotinin administration, and (ii) whether this is associated with excessive postoperative bleeding (> or = 1000 ml/24 h). In a prospective single-blind trial, 120 consecutive patients were randomized to receive 280 mg aprotinin or no aprotinin before skin incision. D-dimer levels increased significantly to the end of surgery, reaching higher levels in the control group. The risk for excessive bleeding was lower in the aprotinin group (12 versus 37%, = 0.001). Fifteen minutes after heparin reversal, patients were at risk for excessive bleeding, when enhanced fibrinolysis was documented (aprotinin group, D-dimer > or = 1.0 micro g/ml, odds ratio = 9.1, = 0.047; control group, D-dimer > or = 3.0 micro g/ml, odds ratio = 4.6, = 0.014). Ninety-seven per cent of the aprotinin group and 81% of control group patients had no excessive bleeding when the D-dimer plasma level was below these values. We conclude that (i) fibrinolytic activity significantly rises under low-dose aprotinin administration, and (ii) plasma D-dimer levels at end of surgery may help to identify patients who are unlikely to develop excessive postoperative bleeding.     

Whole blood laboratory model of thrombocytopenia for use in evaluation of hemostatic interventions

This study describes a laboratory model of whole blood (WB) thrombocytopenia established with blood from healthy volunteers. We obtained a mean platelet count of 16 × 10⁹/l (95% confidence interval, 10–22) in WB by repeatedly replacing the platelet-rich supernatant with autologous platelet-poor plasma from the same individual. Thrombelastographic profiles of WB clot formation and WB clot stability were performed in parallel with measurements of WB platelet aggregation response. Thrombocytopenia reduced the maximum rate of WB clot formation, while ex vivo addition of platelets reversed the coagulopathy of thrombocytopenia. Control experiments revealed minimal changes in coagulation factors, distribution of bloods cells, and platelet activation capabilities. The WB model appears useful in research, development, and evaluation of the effects of hemostatic interventions in thrombocytopenia.     

Activated protein C inhibits thrombus formation in a system with flowing blood

We studied the effect of increasing concentrations of protein C (PC) and activated protein C (APC) on haemostasis in an in vitro thrombosis model. Blood from healthy donors was anticoagulated with citrate–phosphate–dextrose (final citrate concentration 19 m m ) or a low molecular weight heparin (LMWH, 20 IU/ml). Enzymatically denuded rabbit aorta segments were exposed to flowing blood for 10 min in an annular perfusion chamber. PC and APC were added to the perfusate immediately prior to exposure. In citrated blood at a shear rate of 800/s, PC and APC induced a statistically significant decrease in platelet deposit at 16 μg/ml and 32 μg/ml. In perfusions performed with blood anticoagulated with LMWH, there was no effect on platelet deposition at 16 and 32 μg/ml either at shear rates of 300/s or 800/s. Addition of PC showed no effect on fibrin deposition at a shear rate of 300/s; in contrast, a non-statistically significant 40% reduction was seen at a shear rate of 800/s, compared to controls. Addition of APC caused a 100% reduction in fibrin formation at 16 and 32 μg/ml at both shear rates studied. PC and APC inhibited platelet deposition on the exposed subendothelial surface, in a dose-dependent manner. Effects of PC and APC on platelet function might be mediated through inhibition of thrombin generation at the platelet microenvironment.     

Extended storage of whole blood before the preparation of blood components: in vitro effects on red blood cells in Erythro-Sol environment

Background and Objectives  Routine procedures for extended storage of whole blood (WB) before the preparation of blood components are of interest primarily for logistical reasons. We stored red cell units in either Erythro-Sol 2 (E-Sol 2, test units, 150 ml added) or in saline-adenine-glucose–mannitol (SAG-M) (reference units, 100 ml added) that were prepared after storage of WB at room temperature for 8, 12, 16 or 19 h after blood collection.
Study Design and Methods  Red blood cells were stored for 42 days. We measured pH, glucose, lactate, haemolysis, red blood cell adenosine triphosphate and 2,3-diphosphoglycerate on days 1, 7, 14, 21, 28, 35 and 42.
Results  Haematocrits were significantly lower in E-Sol 2 than in SAG-M due to the higher volume of E-Sol 2 added compared to SAG-M. Significantly reduced levels were found in E-Sol 2 of extracellular pH (throughout storage after 8-h hold and initially after 12-, 16- or 19-h hold), of lactate (initially after 8-h hold and throughout storage after 12-, 16- or 19-h hold), and of haemolysis from day 35 in the 8-h and on day 42 in the 12-h hold group. Sigificantly increased levels of adenosine triphosphate were seen in E-Sol 2 after 8-h hold (from day 14) and after 12-h hold (at days 21, 35 and 42) compared to SAG-M. Significantly higher concentrations of 2,3-diphosphoglycerate were noticed primarily after 8-h hold of WB.
Conclusion  The use of E-Sol 2 as a replacement for SAG-M does not significantly improve in vitro data after extended storage of WB at room temperature before preparation of blood components. However, after 8-h hold in vitro characteristics similar to or better than in fresh blood will be maintained for several weeks in E-Sol 2, a situation that makes E-Sol 2 superior to SAG-M when storage of WB is limited to 8 h. Some improvement was noted after 12-h hold as well.     

Effects of preemptive therapy with milrinone or amrinone on perioperative platelet function and haemostasis in patients undergoing coronary bypass grafting

Preemptive therapy with a phosphodiesterase III inhibitor preserves cardiac function and oxygen transport after cardiac surgery, and its safety on platelet function and haemostasis must be verified. We examined the effects of preemptively administered milrinone or amrinone on platelet function and haemostasis. In 45 cardiac surgery patients, we randomly administered milrinone 50 microg/kg plus 0.5 microg/kg/min for 10 hours, amrinone 1.5 mg/kg plus 10 microg/kg/min infusion for 10 hours, or placebo at release of aortic cross-clamp. Whole blood platelet aggregation, haematological values, and postoperative chest drainage were examined. Three patients in the placebo, 1 patient in the amrinone, and 2 patients in the milrinone groups received allogenic blood transfusion (654 +/- 365 ml) intraoperatively, but no patient postoperatively. The mean platelet counts 3 days postoperative in the milrinone and amrinone groups did not significantly differ from the placebo group (10.9 +/- 3.3 and 12.1 +/- 3.8, vs. 12.1 +/- 3.4x10(4) per cubic millimeter, respectively), and chest-tube drainage in the first 24 hours did not significantly differ (450 +/- 156 and 391 +/- 184, vs. 448 +/- 140 ml, respectively). Although there were changes in platelet aggregation consequent to surgery there was no significant differences in platelet aggregation or other haematological values among the three groups. Preemptive therapy of milrinone or amrinone does not deteriorate perioperative platelet function and haemostasis beyond surgical interventions.     

Rapid Preparation of Fresh Platelet Concentrates from CPD-Blood by (Mild) Acidification

Abstract. Two methods of preparation of platelet concentrates (PC) derived from citrate-phosphate-dextrose (CPD) whole blood have been compared: (1) resuspension after having left the PC undisturbed at room temperature for 1 h (according to Mourad), and (2) immediate resuspension of the PC after the centrifugation of a platelet-rich plasma which has been acidified beforehand by the addition of ACD. In vitro platelet yield in acidified (CPD/ACD-)PC was at least equal to and, in cases with a particularly strong postcentrifugal tendency for clumping of platelets, clearly better (p<0.05) than in the 'Mourad platelets'. The results show that it is possible to produce PC from fresh CPD whole blood without delay. This may be helpful in clinical situations where freshly prepared PC should be available immediately. A special double bag (Fenwal DFX 733) containing CPD-A in the primary bag and 10 ml of ACD in the satellite bag, allows preparation of PC under these conditions in a closed system.     

Textilinin-1, an alternative anti-bleeding agent to aprotinin: Importance of plasmin inhibition in controlling blood loss

Aprotinin has been used widely in surgery as an anti-bleeding agent but is associated with a number of side effects. We report that textilinin-1, a serine protease inhibitor from Pseudonaja textilis venom with sequence relatedness to aprotinin, is a potent but reversible plasmin inhibitor and has a narrower range of protease inhibition compared to aprotinin. Like aprotinin, textilinin-1 at 5 μmol/l gave almost complete inhibition of tissue plasminogen activator-induced fibrinolysis of whole blood clots. The activated partial thromboplastin time for plasma was markedly increased by aprotinin but unaffected by textilinin-1. In a mouse tail-vein bleeding model, intravenous textilinin-1 and aprotinin caused similar decreases in blood loss but time to haemostasis in the textilinin-treated animals was significantly shorter than in aprotinin-treated mice. Based on these data, textilinin-1 merits further investigation as a therapeutic alternative to aprotinin.     

Changes in Platelet Demand in Association with the Spread of Autologous Peripheral Blood Progenitor Cell Transplantation

Abstract: Changes in platelet demand accompanying widespread application of autologous peripheral blood progenitor cell transplantation (APBPCT) were anticipated. The differences in the transfused volume of platelet concentrate (PC) among 8 patients with malignant lymphoma who were treated with APBPCT and 10 patients with malignant lymphoma who were not treated with APBPCT, although peripheral blood progenitor cell harvests had been performed, were studied. The former was 81 Japanese PC units more than the latter. Considering the supplied volume of PC from Red Cross blood centers and the number of APBPCTs in 1996 in Japan, the Japanese demand for PC increases by 0.16% for enforced APBPCT versus 0.36%, which includes the PC demand necessary in all treatment courses. The total increment in PC demand associated with APBPCT is not large enough to threaten the PC supply of Japan even if the number of APBPCTs increases rapidly.     

In vitro function of platelet concentrates prepared after filtration of whole blood or buffy coat pools

BACKGROUND/METHOD: Data on the quality of platelet concentrates (PC) produced by the buffy coat method and stored beyond 5 days in plasma are limited. We therefore evaluated the quality of PCs prepared by leucocyte depletion of whole blood (Terumo WBSP, n = 10) or a buffy coat pool (Pall Autostop, n = 10), and stored for 7 days in plasma by assessing platelet parameters and markers of platelet activation. RESULTS: In both types of PC, levels of glucose decreased during storage but were not totally depleted (> 11 mM on day 7). In contrast, lactate levels increased on storage and was consistently < 20 mM throughout, with pH maintained at > 6.8 in all units. Hypotonic shock response scores were > 47% in all units at day 7. On day 1, markers of platelet activation were significantly higher in WBSP PC, but by day 7 were similar for percentage CD63+ and CD62P + (40%) with levels of platelet microparticles and annexin V binding two-fold higher in WBSP. The expression of CD61 did not alter during storage and the percentage of platelets expressing CD42b was > 88% in all units on day 7. RANTES (Regulated on activation, normal, T-cell expressed and secreted) and TGFbeta released from platelets by day 7 was < 800 ng/ml and 90 ng/ml, respectively. C3a(desarg) increased throughout storage in both types of PC, but without a commensurate increase in the terminal complex SC5b-9 or activation of factor XII. CONCLUSION: Our data indicates that the in vitro characteristics of PCs prepared using these methods is maintained over storage for 7 days in plasma and is not associated with significant deterioration of platelet function. ONE SENTENCE SUMMARY: In vitro function of platelet concentrates prepared by either filtration of whole blood, or pooled buffy coats.     

Escherichia coli sepsis from contaminated platelet transfusion

Transfusion of pooled platelet concentrate (PC) caused a septic reaction characterized by sustained hypotension, high cardiac output, and low systemic vascular resistance. Investigation demonstrated the same strain of Escherichia coli in the patient's blood, the transfused pooled PC, and recalled packed red blood cells separated from the same unit of whole blood as one of the platelet units in the contaminated pool. Five hundred other units of PC from the same supplier were cultured prospectively, and 7% were bacterially contaminated. The level of contamination was 20 or fewer colony-forming units per milliliter in all except one unit, the only one associated with a febrile transfusion reaction. This episode illustrates the continuing importance of sepsis as a cause of platelet transfusion reactions and demonstrates the usefulness of appropriate cultures and epidemiologic information in assessing the source.     

The Use of Fresh Plasma and a Plasma-free Medium to Enhance the Aggregation Response of Stored Platelets

Platelet aggregation in response to ADP (10 μM) and collagen (4 μg/ml) in fresh and stored platelet concentrates (PC) and the enhancement of aggregation of the stored platelets after resuspension in fresh plasma and plasma-free medium were measured. The ability of platelets in autologous plasma to respond to the two agonists decreased significantly on days 2 and 5 of storage to 18 and 4% (p < 0.001) respectively of that seen in platelet-rich plasma on day 0 (100%). A 2-fold or greater improvement (p < 0.01) in the aggregation response was achieved when the autologous plasma in stored PC was replaced by fresh allogeneic plasma just before testing. The effect was even greater (three-fold or more, p < 0.001) when the autologous plasma was first replaced by plasma-free medium followed by suitable dilution for the test in fresh allogeneic plasma. These observations indicate another way to rejuvenate stored platelets and enhance their residual capacity to aggregate ex vivo. They could provide a basis for a suitable test for use within a quality assurance programme for stored PC.     

Antifibrinolytic use in adult cardiac surgery

PURPOSE OF REVIEW: Antifibrinolytics are used to attenuate the coagulopathy associated with cardiopulmonary bypass. However, recent studies suggest that the antifibrinolytic aprotinin is associated with increased renal and vascular events and death compared to its alternatives. To develop a recommendation for antifibrinolytic use in adult cardiac surgery, we performed a systematic review and meta-analysis to determine the association of the antifibrinolytics with efficacy, safety and cost outcomes. RECENT FINDINGS: Aprotinin, when compared to placebo, significantly decreased blood transfusions and reoperations for bleeding, strokes and cognitive dysfunction, and significantly increased renal dysfunction but not renal failure. Tranexamic acid significantly decreased blood transfusions, but was not statistically associated with other outcomes. Aminocaproic acid was not statistically associated with any measured outcome. Although aprotinin costs more than its alternatives, its costs may approximate those of its alternatives when longer time horizons are considered. SUMMARY: We support the targeted use of aprotinin in adult cardiac surgery patients at high risk for bleeding or stroke, and discourage the use of aprotinin in those at high risk for renal failure. Although fewer data are available for tranexamic and aminocaproic acid, we support their use as alternatives to aprotinin in those at high risk for bleeding.