Efficacy and Safety of Pathogen-Reduced Platelets Compared with Standard Apheresis Platelets: A Systematic Review of RCTs
Pathogens (Basel, Switzerland). 2022;11(6)
In this systematic review, we evaluate the efficacy and safety of blood components treated with pathogen reduction technologies (PRTs). We searched the Medline, Embase, Scopus, Ovid, and Cochrane Library to identify RCTs evaluating PRTs. Risk of bias assessment and the Mantel-Haenszel method for data synthesis were used. We included in this review 19 RCTs evaluating 4332 patients (mostly oncohematological patients) receiving blood components treated with three different PRTs. Compared with standard platelets (St-PLTs), the treatment with pathogen-reduced platelets (PR-PLTs) does not increase the occurrence of bleeding events, although a slight increase in the occurrence of severe bleeding events was observed in the overall comparison. No between-groups difference in the occurrence of serious adverse events was observed. PR-PLT recipients had a lower 1 and 24 h CI and CCI. The number of patients with platelet refractoriness and alloimmunization was significantly higher in PR-PLT recipients compared with St-PLT recipients. PR-PLT recipients had a higher number of platelet and RBC transfusions compared with St-PLT recipients, with a shorter transfusion time interval. The quality of evidence for these outcomes was from moderate to high. Blood components treated with PRTs are not implicated in serious adverse events, and PR-PLTs do not have a major effect on the increase in bleeding events. However, treatment with PRTs may require a greater number of transfusions in shorter time intervals and may be implicated in an increase in platelet refractoriness and alloimmunization.
Efficacy of UVC-treated, pathogen-reduced platelets versus untreated platelets: a randomized controlled non-inferiority trial
Pathogen reduction (PR) technologies for blood components have been established to reduce the residual risk of known and emerging infectious agents. THERAFLEX UVPlatelets, a novel UVC light-based PR technology for platelet concentrates, works without photoactive substances. This randomized, controlled, double-blind, multicenter, noninferiority trial was designed to compare the efficacy and safety of UVC-treated platelets to that of untreated platelets in thrombocytopenic patients with hematologic-oncologic diseases. Primary objective was to determine non-inferiority of UVC-treated platelets, assessed by the 1-hour corrected count increment (CCI) in up to eight per-protocol platelet transfusion episodes. Analysis of the 171 eligible patients showed that the defined non-inferiority margin of 30% of UVC-treated platelets was narrowly missed as the mean differences in 1-hour CCI between standard platelets versus UVC-treated platelets for intention-to-treat and perprotocol analyses were 18.2% (95% confidence interval [CI]: 6.4%; 30.1) and 18.7% (95% CI: 6.3%; 31.1%), respectively. In comparison to the control, the UVC group had a 19.2% lower mean 24-hour CCI and was treated with an about 25% higher number of platelet units, but the average number of days to next platelet transfusion did not differ significantly between both treatment groups. The frequency of low-grade adverse events was slightly higher in the UVC group and the frequencies of refractoriness to platelet transfusion, platelet alloimmunization, severe bleeding events, and red blood cell transfusions were comparable between groups. Our study suggests that transfusion of pathogen-reduced platelets produced with the UVC technology is safe but non-inferiority was not demonstrated. (The German Clinical Trials Register number: DRKS00011156).
Bacterial contamination rate of platelet components by primary culture: a systematic review and meta-analysis
BACKGROUND Platelets have the highest bacterial contamination risk of all blood components, and septic transfusion reactions remain a problem. A good estimate of contamination rates could provide information about residual risk and inform optimal testing strategies. We performed a systematic review and meta-analysis of platelet contamination rates by primary culture. STUDY DESIGN AND METHODS A literature search in December 2019 identified articles on platelet contamination rates using primary culture. We used meta-analysis to estimate the overall rate of contamination and meta-regression to identify heterogeneity. We studied the following sources of heterogeneity: collection method, sample volume, positivity criteria, and study date. Contamination rate estimates were obtained for apheresis (AP), platelet rich plasma (PRP), and buffy coat (BC) collection methods. RESULTS The search identified 6102 studies, and 22 were included for meta-analysis. Among these 22 studies, there were 21 AP cohorts (4,072,022 components), 4 PRP cohorts (138,869 components), and 15 BC cohorts (1,474,679 components). The overall mean contamination rate per 1000 components was 0.51 (95% CI: 0.38-0.67) including AP (0.23, 95% CI: 0.18-0.28), PRP, (0.38, 95% CI: 0.15-0.70), and BC (1.12, 95% CI: 0.51-1.96). There was considerable variability within each collection method. Sample volume, positivity criteria, and publication year were significant sources of heterogeneity. CONCLUSION The bacterial contamination rate of platelets by primary culture is 1 in 1961. AP and PRP components showed a lower contamination rate than BC components. There is clinically significant between-study variability for each method. Larger sample volumes increased sensitivity, and bacterial contamination rates have decreased over time.
Technical Procedures for Preparation and Administration of Platelet-Rich Plasma and Related Products: A Scoping Review
Frontiers in cell and developmental biology. 2020;8:598816
INTRODUCTION Platelet-rich plasma is widely used for different types of clinical situations, but universal standardization of procedures for its preparation is still lacking. METHODS Scoping review of comparative studies that have assessed at least two alternatives in one or more stages of preparation, storage and/or administration of PRP or its related products. A systematic search was conducted in MEDLINE, Embase, and LILACS. Two authors screened references independently. Data extraction was performed iteratively, and results were presented for each included comparison. RESULTS Thirty-nine studies were included after assessing full texts, focusing on the comparison of PRP to a related product, types of anticoagulants, centrifugation protocols, commercial kits, processing time, methods for activation, and application concomitantly to other substances. Only laboratory outcomes were assessed, as platelet, leukocyte and growth factor concentrations. CONCLUSION Results showed great variability related to methods employed in different stages of PRP processing, which may explain the variability observed in clinical trials assessing the efficacy of PRP for different clinical situations.
Platelet storage duration and its clinical and transfusion outcomes: a systematic review
Critical Care (London, England). 2018;22((1)):185.
BACKGROUND Platelets (PLTs) are usually stored for up to 5 days prior to transfusion, although in some blood services the storage period is extended to 7 days. During storage, changes occur in both PLT and storage medium, which may lead to PLT activation and dysfunction. The clinical significance of these changes remains uncertain. METHODS We performed a systematic review to assess the association between PLT storage time and clinical or transfusion outcomes in patients receiving allogeneic PLT transfusion. We searched studies published in English between January 2000 and July 2017 identified from MEDLINE, Embase, PubMed and the Cochrane Libraries. RESULTS Of the 18 studies identified, five included 4719 critically ill patients (trauma, post-cardiac surgery and a heterogeneous population of critically ill patients) and 13 included 8569 haematology patients. The five studies in critically ill patients were retrospective and did not find any association between PLT storage time when PLTs were stored for up to 5 days and mortality. There was also no association between older PLTs and sepsis in the two largest studies (n = 4008 patients). Of the 13 studies in haematology patients, seven analysed prolonged storage time up to 6.5 or 7 days. Administration of fresh PLTs (less than 2 or 3 days) was associated with a significant increase in corrected count increment (CCI) compared to older PLTs in seven of the eight studies analysing this outcome. One single centre retrospective study found an increase in bleeding events in patients receiving older PLTs. CONCLUSIONS PLT storage time does not appear to be associated with clinical outcomes, including bleeding, sepsis or mortality, in critically ill patients or haematology patients. The freshest PLTs (less than 3 days) were associated with a better CCI, although there was no impact on bleeding events, questioning the clinical significance of this association. However, there is an absence of evidence to draw definitive conclusions, especially in critically ill patients.
Concentrations of blood components in commercial platelet-rich plasma separation systems: a review of the literature
The American Journal of Sports Medicine. 2018;:363546517746112.
BACKGROUND Platelet-rich plasma (PRP) has proven to be a very safe therapeutic option in the treatment of tendon, muscle, bone, and cartilage injuries. Currently, several commercial separation systems are available for the preparation of PRP. The concentrations of blood components in PRP among these separation systems vary substantially. PURPOSE To systematically review and evaluate the differences between the concentrations of blood components in PRP produced by various PRP separation systems. STUDY DESIGN Systematic review. METHODS MEDLINE/PubMed, the Cochrane Central Register of Controlled Trials (CENTRAL), and EMBASE were searched for studies that compared the concentrations of blood components and growth factors in PRP between various separation systems and studies that reported on the concentrations of blood components and growth factors of single separation systems. The primary outcomes were platelet count, leukocyte count, and concentration of growth factors (eg, platelet-derived growth factor-AB [PDGF-AB], transforming growth factor-beta1 [TGF-beta1], and vascular endothelial growth factor [VEGF]). Furthermore, the preparation protocols and prices of the systems were compared. RESULTS There were 1079 studies found, of which 19 studies were selected for inclusion in this review. The concentrations of platelets and leukocytes in PRP differed largely between, and to a lesser extent within, the studied PRP separation systems. Additionally, large differences both between and within the studied PRP separation systems were found for all the growth factors. Furthermore, preparation protocols and prices varied widely between systems. CONCLUSION There is a large heterogeneity between PRP separation systems regarding concentrations of platelets, leukocytes, and growth factors in PRP. The choice for the most appropriate type of PRP should be based on the specific clinical field of application. As the ideal concentrations of blood components and growth factors for the specific fields of application are yet to be determined for most of the fields, future research should focus on which type of PRP is most suitable for the specific field.
Coagulation Factor Activities Changes Over 5 Days in Thawed Fresh Frozen Plasma Stored at Different Initial Storage Temperatures
Indian Journal of Hematology & Blood Transfusion : an Official Journal of Indian Society of Hematology and Blood Transfusion. 2018;34((3)):510-516.
Thawed plasma is fresh frozen plasma (FFP) that has been stored for 5 days at 1-6 degrees C. Duration of storage and different storage temperatures might affect the coagulation factor activity in thawed FFP. This study measured the changes of coagulation factor activities over 5 days in thawed FFP and stored at two different initial storage temperatures. Thirty-six units of FFP, which consisted of nine units each from blood groups A, B, AB, and O, were thawed at 37 degrees C. Each unit was divided into two separate groups (Group A and Group B) based on initial storage temperature. The first group was stored at 2-6 degrees C for 5 days (Group A). The second group was stored at 20-24 degrees C for initial 6 h followed by 2-6 degrees C for 5 days (Group B). Prothrombin time (PT), activated partial thromboplastin time (APTT), coagulation factor activities of fibrinogen, factor (F) II, FV, FVII, FVIII, FIX, FX, and von Willebrand factor antigen (vWF Ag) were assessed at baseline after thawing, at 6 h, and on days 1, 3, and 5 of storage for both groups. All coagulation factors mean activities in both storage groups decreased significantly over 5 days of storage. The mean FVIII activity at day 5 of storage was 36.9% in Group A and 39.8% in Group B. The other coagulation factors mean activities were > 50% on day 5 of storage in both groups. The coagulation factor activities of thawed FFP stored for 5 consecutive days were reduced in the two storage groups but most of the activities were still above 30%. This study suggests that thawed FFP stored for 5 days has the potential to ameliorate coagulation factor deficiencies in affected patients.
Hemostatic efficacy of pathogen-inactivated- versus untreated- platelets: a randomized controlled trial
Pathogen inactivation of platelet concentrates reduces the risk of blood-borne infections. However, its effect on platelet function and hemostatic efficacy of transfusion is unclear. We conducted a randomized noninferiority trial comparing the efficacy of pathogen inactivated platelets using riboflavin and ultraviolet B illumination technology (intervention) compared to standard plasma-stored platelets (control) for the prevention of bleeding in patients with hematologic malignancies and thrombocytopenia. The primary outcome parameter was the proportion of transfusion treatment periods in which the patient had grade 2 or higher bleeding as defined by World Health Organization (WHO) criteria. Between November 2010 and April 2016, 469 unique patients were randomized to 567 transfusion treatment periods (283 in the control arm, 284 in the intervention arm). There was a 3% absolute difference in grade ≥ 2 bleeding in the intention-to-treat analysis: 51% of the transfusion treatment periods in the control arm and 54% in the intervention arm (95% CI -6 to 11, p-value for noninferiority 0.012). In the per-protocol analysis, however, difference in grade ≥ 2 bleeding was 8%: 44% in the control arm and 52% in the intervention arm (95% CI -2 to 18, p-value for noninferiority 0.19). Transfusion increment parameters were about 50% lower in the intervention arm. There was no difference in the proportion of patients developing HLA class I alloantibodies. In conclusion, the noninferiority criterion for pathogen inactivated platelets was met in the intention-to-treat analysis. This finding was not demonstrated in the per protocol analysis. (The Netherlands National Trial Registry number: NTR2106).
Clinical effectiveness of platelets in additive solution treated with two commercial pathogen-reduction technologies
BACKGROUND Two noninferiority, randomized, controlled trials were conducted in parallel comparing the safety and efficacy of platelets treated with Intercept or Mirasol pathogen-reduction technologies versus standard platelets. STUDY DESIGN AND METHODS The primary endpoint was the percentage of hematology patients who developed World Health Organization Grade 2 or greater bleeding. A noninferiority margin of 11% was chosen based on expected Grade 2 or greater bleeding in 20% of controls. The study was closed for financial restrictions before reaching the planned sample size of 828 patients, and an intention-to-treat analysis was conducted on 424 evaluable patients. RESULTS In the Intercept trial (113 treated vs. 115 control patients), the absolute risk difference in Grade 2 or greater bleeding was 6.1%, with an upper one-sided 97.5% confidence limit of 19.2%. The absolute risk difference in the Mirasol trial (99 treated vs. 97 control patients) was 4.1%, and the upper one-sided 97.5% confidence limit was 18.4%. Neither absolute risk difference was statistically significant. In both trials, posttransfusion platelet count increments were significantly lower in treated versus control patients. Mean blood component use in treated patients versus controls was 54% higher (95% confidence interval, 36%-74%; Intercept) and 34% higher (95% confidence interval, 16%-54%; Mirasol) for platelets and 23% higher (95% confidence interval, 8%-39%; Intercept) and 32% higher (95% confidence interval, 10%-57%; Mirasol) for red blood cells. Unexpected reactions and adverse events were not reported. Mortality did not differ significantly between treated and control patients. CONCLUSION Although conclusions on noninferiority could not be drawn due to low statistical power, the study provides additional information on the safety and efficacy of pathogen-reduced platelets treated with two commercial pathogen-reduction technologies.
Effect of storage time of platelet products on clinical outcomes after transfusion: a systematic review and meta-analyses
Vox Sanguinis. 2017;112((4):):291-300
BACKGROUND Prolonged storage improves availability of platelet products but could also influence safety and efficacy. This systematic review and meta-analyses summarize and quantify the evidence of the effect of storage time of transfused platelets on clinical outcomes. METHODS A systematic search in seven databases was performed up to February 2016. All studies reporting storage time of platelet products and clinical outcomes were included. To quantify heterogeneity, I(2) was calculated, and to assess publication bias, funnel plots were constructed. RESULTS Twenty-three studies reported safety outcomes and fifteen efficacy outcomes. The relative risk of a transfusion reaction after old platelets compared to fresh platelets was 1.53 (95% confidence interval (CI): 1.04-2.25) (12 studies). This was 2.05 (CI:1.47-2.85) before and 1.05 (CI: 0.60-1.84) after implementation of universal leucoreduction. The relative risk of bleeding was 1.13 (CI: 0.97-1.32) for old platelets compared to fresh (five studies). The transfusion interval was 0.25 days (CI: 0.13; 0.38) shorter after transfusion of old platelets (four studies). Three studies reported use of platelet products: two for haematological patients and one for trauma patients. Selecting only studies in haematological patients, the difference was 4.51 units (CI: 1.92; 7.11). CONCLUSION Old platelets increase the risk of transfusion reactions in the setting of non-leucoreduction, shorten platelet transfusion intervals, thereby increase the numbers of platelet transfusions in haematological patients, and may increase the risk of bleeding.