Extended storage of autologous apheresis platelets in plasma

Effect of platelet storage duration on clinical outcomes and incremental platelet change in critically ill children

The safety of platelet (PLT) concentrates with longer storage duration has been questioned due to biochemical and functional changes that occur during blood collection and storage. Some studies have suggested that transfusion efficacy is decreased and immune system dysfunction is worsened with increased storage age. We sought to describe the effect of PLT storage age on laboratory and clinical outcomes in critically ill children receiving PLT transfusions.

STUDY DESIGN AND METHODS

We performed a secondary analysis of a prospective, observational point-prevalence study. Children (3 days to 16 years of age) from 82 pediatric intensive care units in 16 countries were enrolled if they received a PLT transfusion during one of the predefined screening weeks. Outcomes (including PLT count increments, organ dysfunction, and transfusion reactions) were evaluated by PLT storage age.

RESULTS

Data from 497 patients were analyzed. The age of the PLT transfusions ranged from 1 to 7 days but the majority were 4 (24%) or 5 (36%) days of age. Nearly two-thirds of PLT concentrates were transfused to prevent bleeding. The indication for transfusion did not differ between storage age groups (P = .610). After patient and product variables were adjusted for, there was no association between storage age and incremental change in total PLT count or organ dysfunction scoring. A significant association between fresher storage age and febrile transfusion reactions (P = .002) was observed.

CONCLUSION

The results in a large, diverse cohort of critically ill children raise questions about the impact of storage age on transfusion and clinical outcomes which require further prospective evaluation.

Factors related to the outcome of prophylactic platelet transfusions in patients with hematologic malignancies: an observational study

BACKGROUND

A better knowledge of the connections between platelet concentrate (PC) characteristics and transfusion outcomes in day-to-day practice would help improve the selection process of the most appropriate PC.

STUDY DESIGN AND METHODS

In this study of prophylactic platelet transfusions in patients with hematologic malignancies between 2002 and 2012, outcome criteria were corrected count increments (CCIs) and platelet transfusion intervals (TIs, in days). Studied characteristics were ABO matching status, platelet source, dose, storage duration, irradiation, washing, and transfusion sequence number (TSN). The analysis consisted of multivariable linear mixed-effects models with adjustments for patient diagnosis, sex, and type of treatment.

RESULTS

Overall, 869 patients and 6662 platelet transfusions were analyzed. For each day after the second day of storage, the CCI and TI decreased by 0.88 and 0.06 day, respectively. Compared to ABO-identical, transfusion with major ABO-incompatible PCs decreased the CCI and TI by 0.79 and 0.21 day, respectively. Platelet washing reduced the CCI and TI by 2.28 and 0.24 day, respectively. There was no significant association between platelet source or irradiation and CCI or TI. TI increased as the platelet dose per kg increased. Both CCI and TI decreased as the TSN increased.

CONCLUSION

Transfusion outcomes were significantly related to several PC-related factors. Associations for ABO matching status and storage duration were stronger than previously reported. Taking into account such factors when selecting a PC for transfusion could be beneficial to the recipient.

The effect of variation in donor platelet function on transfusion outcome: a semirandomized controlled trial

The effect of variation in platelet function in platelet donors on patient outcome following platelet transfusion is unknown. This trial assessed the hypothesis that platelets collected from donors with highly responsive platelets to agonists in vitro assessed by flow cytometry (high-responder donors) are cleared more quickly from the circulation than those from low-responder donors, resulting in lower platelet count increments following transfusion. This parallel group, semirandomized double-blinded trial was conducted in a single center in the United Kingdom. Eligible patients were those 16 or older with thrombocytopenia secondary to bone marrow failure, requiring prophylactic platelet transfusion. Patients were randomly assigned to receive a platelet donation from a high- or low-responder donor when both were available, or when only 1 type of platelet was available, patients received that. Participants, investigators, and those assessing outcomes were masked to group assignment. The primary end point was the platelet count increment 10 to 90 minutes following transfusion. Analysis was by intention to treat. Fifty-one patients were assigned to receive platelets from low-responder donors, and 49 from high-responder donors (47 of which were randomized and 53 nonrandomized). There was no significant difference in platelet count increment 10 to 90 minutes following transfusion in patients receiving platelets from high-responder (mean, 21.0 × 10⁹/L; 95% confidence interval [CI], 4.9-37.2) or low-responder (mean, 23.3 × 10⁹/L; 95% CI, 7.8-38.9) donors (mean difference, 2.3; 95% CI, -1.1 to 5.7; P = .18). These results support the current policy of not selecting platelet donors on the basis of platelet function for prophylactic platelet transfusion.

Impedance aggregometric analysis of platelet function of apheresis platelet concentrates as a function of storage time

Multiple electrode (impedance) aggregometry (MEA) allows reliable monitoring of platelet function in whole blood. The aims of the present study were to implement MEA for analyzing aggregation in platelet concentrates and to correlate results with storage time and blood gas analysis (BGA). We investigated the influence of platelet counts, calcium concentrations and agonists on platelet aggregation. Samples of apheresis concentrates up to an age of 12 days were investigated by MEA and BGA. For ASPI- and TRAPtest MEA was reproducible for a platelet count of 400 per 10^-9L and a calcium concentration of 5 mmol L^-1. Platelets at the age of 2-4 days yielded steady aggregation. Platelet concentrates exceeding the storage time for transfusion showed steady aggregation up to 10 days, but a significant decline on day 12. Weak correlation was found regarding pCO₂ and MEA as well as regarding glucose concentration and MEA. Our results indicate that MEA is applicable for evaluation of aggregation in stored apheresis concentrates. Prolonged storage seems not to be prejudicial regarding platelet aggregation. Platelet concentrates showed acceptable BGA throughout storage time. Further studies are required to evaluate the application of MEA for quality controls in platelet concentrates.

Past, present and forecast of transfusion medicine: What has changed and what is expected to change?

Blood transfusion is the second most used medical procedures in health care systems worldwide. Over the last few decades, significant changes have been evolved in transfusion medicine practices. These changes were mainly needed to increase safety, efficacy, and availability of blood products as well as reduce recipients' unnecessary exposure to allogeneic blood. Blood products collection, processing, and storage as well as transfusion practices throughout all patient populations were the main stream of these changes. Health care systems across the world have adopted some or most of these changes to reduce transfusion risks, to improve overall patients' outcome, and to reduce health care costs. In this article, we are going to present and discuss some of these recent modifications and their impact on patients' safety.

Aging of platelets stored for transfusion

A goal of platelet storage is to maintain the quality of platelets from the point of donation to the point of transfusion - to suspend the aging process. This effort is judged by clinical and laboratory measures with varying degrees of success. Recent work gives encouragement that platelets can be maintained ex vivo beyond the current 5 -7 day shelf life whilst maintaining their quality, as measured by posttransfusion recovery and survival. However, additional measures are needed to validate the development of technologies that may further reduce the aging of stored platelets, or enhance their hemostatic properties.

Responsiveness of platelets during storage studied with flow cytometry--formation of platelet subpopulations and LAMP-1 as new markers for the platelet storage lesion

BACKGROUND AND OBJECTIVES

Storage lesions may prevent transfused platelets to respond to agonists and arrest bleeding. The aim of this study was to evaluate and quantify the capacity of platelet activation during storage using flow cytometry and new markers of platelet activation.

MATERIALS AND METHODS

Activation responses of platelets prepared by apheresis were measured on days 1, 5, 7 and 12. In addition, comparisons were made for platelet concentrates stored until swirling was affected. Lysosome-associated membrane protein-1 (LAMP-1), P-selectin and phosphatidylserine (PS) exposure were assessed by flow cytometry on platelets in different subpopulations in resting state or following stimulation with platelet agonists (cross-linked collagen-related peptide (CRP-XL), PAR1- and PAR4-activating peptides).

RESULTS

The ability to form subpopulations upon activation was significantly decreased already at day 5 for some agonist combinations. The agonist-induced exposure of PS and LAMP-1 also gradually decreased with time. Spontaneous exposure of P-selectin and PS increased with time, while spontaneous LAMP-1 exposure was unchanged. In addition, agonist-induced LAMP-1 expression clearly discriminated platelet concentrates with reduced swirling from those with retained swirling. This suggests that LAMP-1 could be a good marker to capture changes in activation capacity in stored platelets.

CONCLUSION

The platelet activation potential seen as LAMP-1 exposure and fragmentation into platelet subpopulations is potential sensitive markers for the platelet storage lesion.

Evaluation of store lesion in platelet obtained by apheresis compared to platelet derived from whole blood and its impact on the in vitro functionality

Platelet units for transfusion purposes are obtained manually from whole blood or by apheresis, in an automated process. In both methods, platelets during storage present a characteristics grouped under the name "storage lesion" that are associated with adverse effects on platelet units. Oxidative stress has been claimed to be one of major causes, leading to activation and apoptosis processes affecting their post transfusion functionality. In this work, we observed an association between apheresis and a reduced presence of oxidative stress and better results in functional markers in stored platelets, compared to manually obtained platelets. Then, apheresis which would ensure a greater number of functional platelets during the 5 days of storage, compared to concentrates obtained from whole blood.

Clinical and quality evaluation of apheresis vs random-donor platelet concentrates stored for 7 days

BACKGROUND AND OBJECTIVES

The clinical efficacy of different types of platelets remains under debate. We conducted a pilot study to prospectively evaluate the impact of subsequent storage on the in vitro quality and post-transfusion outcome of apheresis prepared platelets (APCs) vs random donor platelets (RDPs).

MATERIALS AND METHODS

We studied 30 units of APCs, and 30 units of RDPs. We performed assays on days 1, 3, 5 and 7, evaluating ADP aggregation, platelet count and pH. Fifteen thrombocytopenic patients with haematologic conditions were evaluated. Each patient received prophylactic transfusions of both components, and their post-transfusion platelet increments were compared. Twenty-five transfusions were apheresis prepared, and 35 transfusions were received as RDPs. None of the RDPs were leukoreduced.

RESULTS

The median platelet counts for APCs on days 1, 3, 5 and 7 were; 2070, 1990, 1680 and 1240 × 10(3)  µL(-1) , respectively, and were; 1290, 850, 499 and 284 × 10(3)  µL(-1) , respectively for RDPs. The pH of all units was more than 6·2. Both groups demonstrated a significant decrease of ADP aggregation after 3 days of storage (P < 0·05). However, APCs provided satisfactory increments for 90·9% of transfusions. On the sixth and seventh days of storage, APCs provided significantly higher platelet increments (18·7 × 10(3)  µL(-1) ) compared with RDPs (3·20 × 10(3)  µL(-1) ) (P < 0·05). Significantly longer transfusion intervals were also achieved with APCs (P < 0·05).

CONCLUSION

Although other variables may have confounded the results, subsequent storage of APCs appeared to provide higher increments with longer intervals of transfusion compared with RDPs. Future prospective studies are needed, adjusting for other possible confounding variables.

A randomized noninferiority crossover trial of corrected count increments and bleeding in thrombocytopenic hematology patients receiving 2- to 5- versus 6- or 7-day-stored platelets

BACKGROUND

Bacterial screening offers the possibility of extending platelet (PLT) storage to Day 7. We conducted a noninferiority, crossover trial comparing PLTs stored for 6 or 7 days versus 2 to 5 days.

STUDY DESIGN AND METHODS

Stable hematology patients were allocated to receive blocks of 2- to 5- and 6- or 7-day PLTs in random order. The primary outcome was the proportion of successful transfusions during the first block, defined as a corrected count increment (CCI) of more than 4.5 at 8 to 24 hours posttransfusion.

RESULTS

Of 122 patients with an evaluable first block, 87 (71%) and 84 (69%) had successful transfusions after 2- to 5- and 6- or 7-day PLTs of mean (SD) ages of 3.8 (1.0) and 6.4 (0.5) days, respectively. Six- or 7-day PLTs were declared noninferior to 2- to 5-day PLTs since the upper confidence interval (CI) limit was less than the predefined noninferiority margin of 10% (95% CI, -14.0% to 9.1%; p = 0.766). Logistic regression analysis gave an adjusted odds ratio of 0.86 (95% CI, 0.47-1.58; p = 0.625). Mean (SD) 8- to 24-hour CCIs were 9.4 (7.9) and 7.7 (7.1) after transfusion with 2- to 5- or 6- or 7-day PLTs (95% CI, -3.31 to 0.03; p = 0.054). The proportions of days with bleeding scores of WHO Grade 2 or higher were 13% (38/297 days) and 11% (32/296 days; 95% CI, -3.2 to 7.2; p = 0.454). Median interval to next PLT transfusion (2 days) was unaffected (95% CI, -10.5 to 5.4; p = 0.531).

CONCLUSION

In hematology patients, there was no evidence that 6- or 7-day PLTs were inferior to 2- to 5-day PLTs, as measured by proportion of patients with successful transfusions, bleeding events, or interval to next transfusion.

Exploratory studies of extended storage of apheresis platelets in a platelet additive solution (PAS)

To evaluate the poststorage viability of apheresis platelets stored for up to 18 days in 80% platelet additive solution (PAS)/20% plasma, 117 healthy subjects donated platelets using the Haemonetics MCS+, COBE Spectra (Spectra), or Trima Accel (Trima) systems. Control platelets from the same subjects were compared with their stored test PAS platelets by radiolabeling their stored and control platelets with either (51)chromium or (111)indium. Trima platelets met Food and Drug Administration poststorage platelet viability criteria for only 7 days vs almost 13 days for Haemonetics platelets; ie, platelet recoveries after these storage times averaged 44 ± 3% vs 49 ± 3% and survivals were 5.4 ± 0.3 vs 4.6 ± 0.3 days, respectively. The differences in storage duration are likely related to both the collection system and the storage bag. The Spectra and Trima platelets were hyperconcentrated during collection, and PAS was added, whereas the Haemonetics platelets were elutriated with PAS, which may have resulted in less collection injury. When Spectra and Trima platelets were stored in Haemonetics' bags, poststorage viability was significantly improved. Platelet viability is better maintained in vitro than in vivo, allowing substantial increases in platelet storage times. However, implementation will require resolution of potential bacterial overgrowth during storage.

Resuscitation of trauma-induced coagulopathy

For 30 years, the Advanced Trauma Life Support course of the American College of Surgeons taught that coagulopathy was a late consequence of resuscitation of injury. The recognition of trauma-induced coagulopathy overturns that medical myth and creates a rationale for procoagulant resuscitation. Analysis of the composition of currently available blood components allows prediction of the upper limits of achievable coagulation activity, keeping in mind that oxygen transport must be maintained simultaneously. RBCs, plasma, and platelets given in a 1:1:1 unit ratio results in a hematocrit of 29%, plasma concentration of 62%, and platelet count of 90,000 in the administered resuscitation fluid. Additional amounts of any 1 component dilute the other 2 and any other fluids given dilute all 3. In vivo recovery of stored RBCs is ∼90% and that of platelets ∼60% at the mean age at which such products are given to trauma patients. This means that useful concentrations of the administered products are a hematocrit of 26%, a plasma coagulation factor activity of 62% equivalent to an international normalized ratio of ∼1.2, and a platelet count of 54,000. This means there is essentially no good way to give blood products for resuscitation of trauma-induced coagulopathy other than 1:1:1. Because 50% of trauma patients admitted alive to an academic-level 1 trauma center who will die of uncontrolled hemorrhage will be dead in 2 hours, the trauma system must be prepared to deliver plasma- and platelet-based resuscitation at all times.