Evaluation of a new whole-blood filter that allows preparation of platelet concentrates by platelet-rich plasma methods

Abstract Platelet concentrates prepared in acidified plasma (pH 6.5-6.7) are superior to concentrates prepared by standard methods, and are 80-90 per cent as effective as platelet rich plasma (PRP). The use of excess citric acid to acidify plasma promotes resuspension of the concentrate by eliminating clumping, which is a major factor in the decreased effectiveness of standard concentrates. Analysis of posttransfusion recovery and survival of platelets reveals no evidence of platelet injury in an acid medium. Acidification of PRP inhibits the aggregation of platelets by adenosine diphosphate (ADP). The presence of endogenous ADP may be an important factor in clumping during standard concentrate preparation. A method of acidification of PRP using citric acid is described which allows preparation of an effective concentrate from fresh whole blood without subjecting the red cells to acid pH. Reconstitution of the acidified platelet poor plasma and its native red cells increases the citrate molarity by less than 6 per cent and results in minimal decrease in pH of the whole blood.

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In Vivo Evaluation of Extended Stored Platelet Concentrates.

Blood ◽

10.1182/blood.v108.11.946.946 ◽

2006 ◽

Vol 108 (11) ◽

pp. 946-946 ◽

Cited By ~ 3

Author(s):

Sherrill J. Slichter ◽

Doug Bolgiano ◽

Jill Corson ◽

Mary Kay Jones ◽

Todd Christoffel ◽

...

Keyword(s):

Whole Blood ◽

Platelet Rich Plasma ◽

Storage Conditions ◽

Mean Value ◽

Platelet Concentrates ◽

In Vivo Evaluation ◽

Platelet Storage ◽

Volunteer Donor ◽

Simple Ratio

Abstract Background: With the introduction of bacterial testing, extended storage of platelets is now possible as long as platelet viability is maintained. Although apheresis platelets have recently been licensed for seven days of storage, platelet concentrates are still only licensed for five days. We performed studies to determine the post-storage viability of platelets stored as concentrates. As yet, there are no established criteria for platelet viability that must be met at the end of storage. However, two different criteria for evaluating post-storage platelet viability have been suggested: compare the stored platelet results with each donor’s fresh platelet results; or establish a fixed platelet standard with an expected mean value along with the lower limit of the 95% confidence interval (lower 95% CI) of the mean. Methods: Forty-four normal volunteers donated a unit of whole blood, the whole blood was centrifuged to give platelet-rich plasma (PRP), and the PRP was then centrifuged to produce a platelet concentrate. The platelet concentrates were re-suspended and stored in either 100% plasma or in 20% plasma and 80% Plasmalyte (a platelet storage solution) for five to eight days in Terumo Teruflex bags. At the end of storage, a sample of blood was obtained from each volunteer to prepare fresh platelets to compare the results of a fresh platelet transfusion with the transfusion of the same volunteer’s stored platelets. The fresh and stored platelets were alternately radiolabeled with either 51Cr or 111In, re-injected into their volunteer donor, and serial blood samples were drawn from the volunteer after transfusion of the fresh and stored platelets to determine platelet recoveries and survivals. Results: Results are shown in Table 1. Conclusions: After seven days of storage in plasma, the platelets could qualify for standards of: 74% and 53% as a simple ratio of fresh to stored platelet recoveries and survivals, respectively; according to Dumont’s method of analysis (Transfusion, in press), achievable stored platelet recoveries would be 63% of fresh and survivals would be 40% of fresh; and as a fixed standard, platelet recoveries averaged 45% and survivals 4.4 days with lower 95% CI’s of 35% and 3.3 days, respectively. After eight days of storage in plasma, platelet recoveries and survivals gave unacceptable results. Instead of increasing or at least maintaining post-storage platelet viability, Plasmalyte markedly reduced platelet viability compared to plasma stored platelets at each storage interval. In Vivo Radiolabeled Autologous Platelet Recoveries and Survivals STORAGE CONDITIONS PLATELET RECOVERIES (%) PLATELET SURVIVALS (Days) Solution Time (Days) N Fresh Stored Fresh Stored Data are given as the average ±1 S.D. Plasma 5 10 62±12 55±11 7.7±1.5 6.1±1.0 Plasma 6 10 61±7 46±12 8.2±1.5 5.1±1.6 Plasmalyte 6 3 47±30 29±16 5.1±3.4 1.8±0.2 Plasma 7 10 61±11 45±14 8.3±1.0 4.4±1.5 Plasmalyte 7 5 62±17 30±12 7.4±0.6 2.2±1.1 Plasma 8 3 67±12 31±8 8.3±0.6 2.9±0.8 Plasmalyte 8 3 70±3 21±8 8.2±0.8 0.7±0.1

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Reversal Strategy For Antagonizing The P2Y12-Inhibitor Ticagrelor By Platelet Concentrates

Blood ◽

10.1182/blood.v122.21.1153.1153 ◽

2013 ◽

Vol 122 (21) ◽

pp. 1153-1153

Author(s):

Hobl Eva-Luise ◽

Petra Jilma-Stohlawetz ◽

Ulla Derhaschnig ◽

Schoergenhofer Christian ◽

Michael Schwameis ◽

...

Keyword(s):

Platelet Aggregation ◽

Whole Blood ◽

Ex Vivo ◽

Platelet Reactivity ◽

Platelet Rich Plasma ◽

Loading Dose ◽

Platelet Concentrates ◽

P2y12 Inhibitor ◽

Autologous Platelet Rich Plasma ◽

Autologous Platelet

Abstract Background Patients on anti-platelet therapy have a higher incidence of bleeding complications and reversal of anti-platelet drug effects is an important issue in emergency situations. For old and conventional anti-coagulants, reversal strategies are established. However, there is no experience or recommendation how to antagonize the reversible and highly effective P2Y12-inhibitor ticagrelor and how to restore platelet function following ticagrelor dosing. The aim of this study was to investigate an ex vivo model to reverse the effects of ticagrelor and to estimate the optimal quantity of platelet transfusions required to normalize platelet aggregation. Methods Healthy volunteers (n=20) ingested a loading dose of 180 mg ticagrelor. Blood samples were obtained at baseline to gain autologous platelet rich plasma and to perform aggregation studies after 3h, i.e. at the time of expected maximal ticagrelor concentrations and maximimal platelet inhibition. To normalize platelet aggregation, increasing amounts of autologous platelet rich plasma (PRP) were added ex vivo to hirudin anti-coagulated blood, by spiking PRP into blood at ratios of 1:10, 1:5 and 1:3. Platelet aggregation was assessed by whole blood multiple electrode aggregometry (MEA; Multiplate). For interpretation of aggregation, we defined a cutoff level of 40 U (Units) as the lower limit of the normal range. Volunteers above this level were considered to exhibit normal platelet reactivity. Nonparametric tests were used and statistical comparisons were performed with the Friedman ANOVA, and the Wilcoxon test for post-hoc comparisons. A two-tailed p-value of less than 0.05 was considered significant. Results Ingestion of 180 mg ticagrelor reduced average aggregation responses from 71 to 16 A.U. (p<0.001) and the platelet reactivity index in the VASP-assay from 88 to 22 units (p<0.001) A clear dose-response was obtained after spiking whole blood with increasing amounts of PRP. After addition of PRP at a ratio of 1:10, platelet aggregation increased to 31±14 U. When assuming that one apheresis platelet concentrate (200 mL) typically contains a minimum of 2 x1011 platelets, the ratio of 1:10 corresponds to 0.5 units of apheresis platelet concentrates. A ratio of 1:5 – equivalent to 1 unit of platelet concentrates – increased ADP induced platelet aggregation to 41±14 U. Platelet aggregation increased further to 48±18 U following the addition of PRP at a ratio of 1:3, which corresponds to 1.5 units of platelet concentrates (figure 1). All comparisons were significant at p<0.01. Conclusion Platelets dose-dependently improved ex vivo platelet aggregation of subjects after a loading dose of 180 mg of ticagrelor. It is estimated that > 2 units of apheresis platelet concentrates will be necessary to completely restore baseline platelet aggregation in the majority of patients. Point-of-care platelet function tests may be suitable tools to verify this concept in emergency patients and to estimate the extent of the reversal and de-risk on an individual patient’s level. Disclosures: No relevant conflicts of interest to declare.

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Reevaluation of the resting time period when preparing whole blood-derived platelet concentrates with the platelet-rich plasma method

Transfusion ◽

10.1111/j.1537-2995.2006.00756.x ◽

2006 ◽

Vol 46 (4) ◽

pp. 572-577 ◽

Cited By ~ 9

Author(s):

Gary Moroff ◽

Linda Kline ◽

Michelle Dabay ◽

Suzanne Hunter ◽

Adrienne Johnson ◽

...

Keyword(s):

Whole Blood ◽

Platelet Rich Plasma ◽

Platelet Concentrates ◽

Plasma Method ◽

Time Period ◽

Resting Time

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Effect of bedside filtration on aggregates from cold‐stored whole blood–derived platelet‐rich plasma and apheresis platelet concentrates

Transfusion ◽

10.1111/trf.16741 ◽

2021 ◽

Author(s):

Valery J. Li ◽

S. Lawrence Bailey ◽

Jeffrey Miles ◽

Chomkan Usaneerungrueng ◽

Lydia Y. Fang ◽

...

Keyword(s):

Whole Blood ◽

Platelet Rich Plasma ◽

Platelet Concentrates

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Time Dependence of Whole Blood Aggregation in Response to Platelet Activating Factor (PAF)

Thrombosis and Haemostasis ◽

10.1055/s-0038-1642746 ◽

1988 ◽

Vol 59 (02) ◽

pp. 162-163 ◽

Cited By ~ 5

Author(s):

R R Taylor ◽

J Strophair ◽

M Sturm ◽

R Vandongen ◽

L J Beilin

Keyword(s):

Time Dependence ◽

Whole Blood ◽

Platelet Rich Plasma ◽

Platelet Activating Factor ◽

Sampling Time ◽

Blood Sampling ◽

Impedance Aggregometry

SummaryThe aggregation/adhesion response to platelet activating factor (PAF) was studied in diluted whole blood by impedance aggregometry. The extent of aggregation varied directly with the interval between blood sampling and aggregation measurement over the first 30 minutes from sampling, then remained stable for the next 60 minutes of observation. This is an effect opposite to that described for aggregation to PAF in platelet rich plasma which, however, cannot be studied soon after sampling. Time dependence of aggregation is important and comparative measurements should be made during the period of stable aggregability.

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Macroaggregation of Platelets in Plasma, as Distinct from Microaggregation in Whole Blood (and Plasma), as Determined Using Optical Aggregometry and Platelet Counting respectively, is Specifically Impaired following Cardiopulmonary Bypass in Man

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648905 ◽

1994 ◽

Vol 72 (04) ◽

pp. 511-518 ◽

Cited By ~ 30

Author(s):

Valentine C Menys ◽

Philip R Belcher ◽

Mark I M Noble ◽

Rhys D Evans ◽

George E Drossos ◽

...

Keyword(s):

Cardiac Surgery ◽

Platelet Count ◽

Cardiopulmonary Bypass ◽

Whole Blood ◽

Platelet Rich Plasma ◽

Interquartile Range ◽

Contributory Factor ◽

Platelet Aggregability ◽

Aggregate Growth

SummaryWe determined changes in platelet aggregability following cardiopulmonary bypass, using optical aggregometry to assess macroaggregation in platelet-rich plasma (PRP), and platelet counting to assess microaggregation both in whole blood and PRP. Hirudin was used as the anticoagulant to maintain normocalcaemia.Microaggregation (%, median and interquartile range) in blood stirred with collagen (0.6 µg/ml) was only marginally impaired following bypass (91 [88, 93] at 10 min postbypass v 95 (92, 96] prebypass; n = 22), whereas macroaggregation (amplitude of response; cm) in PRP stirred with collagen (1.0µg/ml) was markedly impaired (9.5 [8.0, 10.8], n = 41 v 13.4 [12.7,14.3], n = 10; p <0.0001). However, in PRP, despite impairment of macroaggregation (9.1 [8.5, 10.1], n = 12), microaggregation was near-maximal (93 [91, 94]), as in whole blood stirred with collagen. In contrast, in aspirin-treated patients (n = 14), both collagen-induced microaggregation in whole blood (49 [47, 52]) and macroaggregation in PRP (5.1 [3.8, 6.6]) were more markedly impaired, compared with control (both p <0.001).Similarly, in PRP, macroaggregation with ristocetin (1.5 mg/ml) was also impaired following bypass (9.4 [7.2, 10.7], n = 38 v 12.4 [10.0, 13.4]; p <0.0002, n = 20), but as found with collagen, despite impairment of macroaggregation (7.2 [3.5,10.9], n = 12), microaggregation was again near-maximal (96 [93,97]). The response to ristocetin was more markedly impared after bypass in succinylated gelatin (Gelo-fusine) treated patients (5.6 [2.8, 8.6], n = 17; p <0.005 v control), whereas the response to collagen was little different (9.3 v 9.5). In contrast to findings with collagen in aspirin-treated patients, the response to ristocetin was little different to that in controls (8.0 v 8.3). Impairment of macroaggregation with collagen or ristocetin did not correlate with the duration of bypass or the platelet count, indicating that haemodilution is not a contributory factor.In conclusion: (1) Macroaggregation in PRP, as determined using optical aggregometry, is specifically impaired following bypass, and this probably reflects impairment of the build-up of small aggregates into larger aggregates. (2) Impairment of aggregate growth and consolidation could contribute to the haemostatic defect following cardiac surgery.

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Haemostatic Platelet Plug Formation in the Isolated Rabbit Mesenteric Preparation - An Analysis of Red Blood Cell Participation

Thrombosis and Haemostasis ◽

10.1055/s-0038-1650069 ◽

1980 ◽

Vol 44 (01) ◽

pp. 006-008 ◽

Cited By ~ 12

Author(s):

D Bergqvist ◽

K-E Arfors

Keyword(s):

Whole Blood ◽

Platelet Rich Plasma ◽

Adenosine Diphosphate ◽

In Vitro Test ◽

Pharmacological Agents ◽

Vitro Test ◽

Releasing Effect ◽

Plug Formation

SummaryIn a model using an isolated rabbit mesenteric preparation microvessels were transected and the time until haemostatic plugs formed was registered. Perfusion of platelet rich plasma gave no haemostasis whereas whole blood did. Addition of chlorpromazine or adenosine to the whole blood significantly prolonged the time for haemostasis, and addition of ADP to the platelet rich plasma significantly shortened it. It is concluded that red cells are necessary for a normal haemostasis in this model, probably by a combination of a haemodynamic and ADP releasing effect.The fundamental role of platelets in haemostatic plug formation is unquestionable but there are still problems concerning the stimulus for this process to start. Three platelet aggregating substances have been discussed – thrombin, adenosine diphosphate (ADP) and collagen. Evidence speaking in favour of thrombin is, however, very minimal, and the discussion has to be focused on collagen and ADP. In an in vitro system using polyethylene tubings we have shown that "haemostasis" can be obtained without the presence of collagen but against these results can be argued that it is only another in vitro test for platelet aggregation (1).To be able to induce haemostasis in this model, however, the presence of red blood cells is necessary. To further study this problem we have developed a model where haemostatic plug formation can be studied in the isolated rabbit mesentery and we have briefly reported on this (2).Thus, it is possible to perfuse the vessels with whole blood as well as with platelet rich plasma (PRP) and different pharmacological agents of importance.

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Antiheparin Activity of Human Serum and Platelet Factor 4

Thrombosis and Haemostasis ◽

10.1055/s-0038-1649105 ◽

1973 ◽

Vol 30 (01) ◽

pp. 093-105 ◽

Cited By ~ 1

Author(s):

C.H.J Sear ◽

L Poller ◽

F.R.C Path

Keyword(s):

Molecular Weight ◽

Ionic Strength ◽

Blood Serum ◽

Whole Blood ◽

Platelet Rich Plasma ◽

Gel Filtration ◽

Normal Serum ◽

Platelet Factor ◽

Mean Values ◽

Antiheparin Activity

SummaryThe antiheparin activity of normal serum has been studied by comparing the antiheparin activities of sera obtained from normal whole blood, platelet-rich plasma and platelet-’free’ plasma with a purified platelet extract during differential isoelectric precipitation and by gel filtration chromatography.The mean values for the activity of PRP-serum and PFP-serum were 106% (S.D. 11) and 10% (S.D. 3) of untreated whole blood respectively. The activity of whole blood serum, PRP serum and whole blood serum plus platelet extract precipitated under identical physical conditions, i.e. pH 7.0, I =0.008, indicating that the activities of the three samples are probably associated with PF4. PF4 precipitated from human platelet extract at pH 4.0, but this is probably due to the difference in the two biochemical environments investigated, i.e. serum and platelet extract.The gel filtration experiments revealed striking similarities between the major antiheparin activities of serum and platelet extract. At physiological pH and ionic strength both activities were associated with high molecular weight material, but at physiological pH and elevated ionic strength both activities behaved as much smaller entities of molecular weight between 25,000 and 30,000 daltons and it seems very likely that both activities are associated with the same molecule, i.e. PF4.

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