The efficiency of transfusing high doses of platelets in hematologic patients with thrombocytopenia: results of a prospective, randomized, open, blinded end point (PROBE) study

The appropriateness of platelet transfusions in hematological patients and the potential for improvement

BACKGROUND

Hematology patients are intensive platelet users. In clinical practice, a substantial proportion of platelet (PLT) transfusions are routinely administered outside the guidelines despite compelling evidence for recommendations. Those unnecessary PLT transfusions are an unjustified extra burden on a scarce healthcare resource and may also be detrimental to the patients. This study aims to evaluate indications and assess the appropriateness of PLT transfusion, as well as to identify common discrepancies and propose modalities for better compliance with guidelines.

MATERIAL AND METHODS

The audit of all PLT orders for adult hematological inpatients was conducted over 2 months. The assessment was performed using guidelines for PLT transfusion. Patient demographic, clinical, and transfusion data were collected from hospital electronic medical records.

RESULTS

Based on 286 PLT orders, 344 PCs were transfused to 67 patients: 235 (82.2%) prophylactical due to low PLT count, 34 (11.9%) preprocedural and 17 (5.9%) therapeutic. Overall, 105 (36.77%) PLT transfusions were inappropriate: 78 (33.2%) of all prophylactic PLT transfusions due to low PLT count, 17 (50%) off all preprocedural and 10 (58.8%) of all therapeutical transfusion. The major reason for PLT transfusion inappropriateness was transfusion above the recommended threshold. Double units of PCs were transfused in 36.7% of all PLT transfusions and 32.4% of them were considered inappropriate.

CONCLUSION

Our audit of PLT transfusion practice found a large proportion of inappropriate PLT transfusions. Based on the most common deviations from the guidelines a variety of targeted measures for improvement are proposed.

A data-informed system to manage scarce blood product allocation in a randomized controlled trial of convalescent plasma

BACKGROUND

Equitable allocation of scarce blood products needed for a randomized controlled trial (RCT) is a complex decision-making process within the blood supply chain. Strategies to improve resource allocation in this setting are lacking.

METHODS

We designed a custom-made, computerized system to manage the inventory and allocation of COVID-19 convalescent plasma (CCP) in a multi-site RCT, CONCOR-1. A hub-and-spoke distribution model enabled real-time inventory monitoring and assignment for randomization. A live CCP inventory system using REDCap was programmed for spoke sites to reserve, assign, and order CCP from hospital hubs. A data-driven mixed-integer programming model with supply and demand forecasting was developed to guide the equitable allocation of CCP at hubs across Canada (excluding Québec).

RESULTS

18/38 hospital study sites were hubs with a median of 2 spoke sites per hub. A total of 394.5 500-ml doses of CCP were distributed; 349.5 (88.6%) doses were transfused; 9.5 (2.4%) were wasted due to mechanical damage sustained to the blood bags; 35.5 (9.0%) were unused at the end of the trial. Due to supply shortages, 53/394.5 (13.4%) doses were imported from Héma-Québec to Canadian Blood Services (CBS), and 125 (31.7%) were transferred between CBS regional distribution centers to meet demand. 137/349.5 (39.2%) and 212.5 (60.8%) doses were transfused at hubs and spoke sites, respectively. The mean percentages of total unmet demand were similar across the hubs, indicating equitable allocation, using our model.

CONCLUSION

Computerized tools can provide efficient and immediate solutions for equitable allocation decisions of scarce blood products in RCTs.

A systematic literature review on the use of platelet transfusions in patients with thrombocytopenia

Objective: Investigate globally, current treatment patterns, benefit-risk assessments, humanistic, societal and economic burden of platelet transfusion (PT). Methods: Publications from 1998 to June 27, 2018 were identified, based on databases searches including MEDLINE®; Embase and Cochrane Database of Systematic Reviews. Data from studies meeting pre-specified criteria were extracted and validated by independent reviewers. Data were obtained for efficacy and safety from randomized controlled trials (RCTs); data for epidemiology, treatment patterns, effectiveness, safety, humanistic and societal burden from real-world evidence (RWE) studies; and economic data from both. Results: A total of 3425 abstracts, 194 publications (190 studies) were included. PT use varied widely, from 0%-100% of TCP patients; 1.7%-24.5% in large studies (>1000 patients). Most were used prophylactically rather than therapeutically. 5 of 43 RCTs compared prophylactic PT with no intervention, with mixed results. In RWE studies PT generally increased platelet count (PC). This increase varied by patient characteristics and hence did not always translate into a clinically significant reduction in bleeding risk. Safety concerns included infection risk, alloimmunization and refractoriness with associated cost burden. Discussion: In RCTs and RWE studies there was significant heterogeneity in study design and outcome measures. In RWE studies, patients receiving PT may have been at higher risk than those not receiving PT creating potential bias. There were limited data on humanistic and societal burden. Conclusion: Although PTs are used widely for increasing PC in TCP, it is important to understand the limitations of PTs, and to explore the use of alternative treatment options where available.

Comparison of efficacy of low and high dose prophylactic platelet transfusion therapy in thrombocytopenic haemato-oncology patients

INTRODUCTION

To determine an optimal platelet dose in thrombocytopenic patients is important for their judicious use. Transfusing platelets in different doses and comparing their post transfusion response can achieve this.

AIM

To compare the efficacy of low and high dose single donor apheresis platelets (SDAP) with standard dose transfusions in terms of Corrected Count Increment (CCI), Percent Platelet Recovery (PPR) and transfusion free interval.

METHOD

It was a prospective case control study done from January 2016 to April 2017. Twenty-eight hemato-oncology patients with CCI ≥5000 at 20-24 hours after standard dose (3 × 10¹¹/unit), received low dose (1.5 × 10¹¹ platelets/unit) and high dose (>4 × 10¹¹ platelets/unit) SDAP. CCI and PPR were calculated after 20 to 24 hours of transfusion. Transfusion free interval and bleeding episodes were also noted. Grading was done according to WHO bleeding scale.

RESULT

There was no statistical difference in CCI and PPR when standard dose was compared with low dose (CCI: p = 0.92, PPR: p = 0.89). When standard and high dose was compared, standard dose gave better results than the high dose in terms of CCI (p = 0.006) and PPR (p = 0.008) although the post transfusion increments were comparable (p = 0.938). High dose gave better (p = 0.005) platelet count increments than low dose but CCI (p = 0.04) and PPR (p = 0.05) was significantly less than the low dose. The difference in transfusion free intervals after three doses was not significant. Donor exposure to the patients was significantly (p = 0.000) reduced to 17.5%.

CONCLUSION

Possibility of low dose as an alternative to standard dose can be considered in view of comparable platelet response indicators and significantly reduced donor exposure.

[Comparative study on platelet transfusion in Lorraine-Champagne and Alsace in 2015]

OBJECTIVES

To find explanations for the observed differences of platelets concentrates (PC) deliveries between 2 French regions, Lorraine-Champagne (LOCH) and Alsace (ALSA).

METHODS

This is a non-interventional prospective study, performed during 30 days in 2015 in intensive care, cardiovascular surgery and onco-hematological wards of 8 LOCH and ALSA hospitals. Questionnaires listing clinical and biological parameters were attached to the prescription forms and filled in at each PC prescription.

RESULTS

In all, 290 patients, 1093 prescriptions and 1093 deliveries of PC were analyzed. The pre-transfusional context (patient weight, prophylactic or curative situation, pre-transfusional platelet count) were homogenous. The phasing of the prescription forms wording had a direct impact on the doses' formulation : 100 % of the LOCH forms were expressed in platelet quantity (PQ), vs 22 % in ALSA. The mean interval between 2 transfusions was 2.9 days in ALSA vs 4.9 days in LOCH. The mean PQ/delivery was higher in ALSA (5.6.10¹¹ vs 4.0.10¹¹ in LOCH). The delivered PQs were compared to the 2003 French recommendations that were in force in 2015. Twenty-seven percent of the LOCH delivered PQs were in the recommended interval, vs Forty-nine percent in ALSA. Due to the systematic delivery of a single PC unit, including weights>80Kg, LOCH presented 63 % insufficient PQ deliveries. Twenty-two percent of the deliveries in ALSA were over the recommended interval, mostly linked with the simultaneous delivery of a second PC.

CONCLUSION

This study identifies disparities in terms of prescription and delivery between LOCH and ALSA, which may explain their respective PC consumption levels.

Platelet transfusion: Current challenges

Since the late sixties, platelet concentrates are transfused to patients presenting with severe thrombocytopenia, platelet function defects, injuries, or undergoing surgery, to prevent the risk of bleeding or to treat actual hemorrhage. Current practices differ according to the country or even in different hospitals and teams. Although crucial advances have been made during the last decades, questions and debates still arise about the right doses to transfuse, the use of prophylactic or therapeutic strategies, the nature and quality of PC, the storage conditions, the monitoring of transfusion efficacy and the microbiological and immunological safety of platelet transfusion. Finally, new challenges are emerging with potential new platelet products, including cold stored or in vitro produced platelets. The most debated of these points are reviewed.

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.

Prophylactic platelet transfusion prior to central venous catheter placement in patients with thrombocytopenia: study protocol for a randomised controlled trial

BACKGROUND

Severe thrombocytopenia should be corrected by prophylactic platelet transfusion prior to central venous catheter (CVC) insertion, according to national and international guidelines. Even though correction is thought to prevent bleeding complications, evidence supporting the routine administration of prophylactic platelets is absent. Furthermore, platelet transfusion bears inherent risk. Since the introduction of ultrasound-guided CVC placement, bleeding complication rates have decreased. The objective of the current trial is, therefore, to demonstrate that omitting prophylactic platelet transfusion prior to CVC placement in severely thrombocytopenic patients is non-inferior compared to prophylactic platelet transfusion.

METHODS/DESIGN

The PACER trial is an investigator-initiated, national, multicentre, single-blinded, randomised controlled, non-inferior, two-arm trial in haematologic and/or intensive care patients with a platelet count of between 10 and 50 × 10⁹/L and an indication for CVC placement. Consecutive patients are randomly assigned to either receive 1 unit of platelet concentrate, or receive no prophylactic platelet transfusion prior to CVC insertion. The primary endpoint is WHO grades 2-4 bleeding. Secondary endpoints are any bleeding complication, costs, length of intensive care and hospital stay and transfusion requirements.

DISCUSSION

This is the first prospective, randomised controlled trial powered to test the hypothesis of whether omitting forgoing platelet transfusion prior to central venous cannulation leads to an equal occurrence of clinical relevant bleeding complications in critically ill and haematologic patients with thrombocytopenia.

TRIAL REGISTRATION

Nederlands Trial Registry, ID: NTR5653 ( http://www.trialregister.nl/trialreg/index.asp ). Registered on 27 January 2016. Currently recruiting. Randomisation commenced on 23 February 2016.

Consensus Report by the Pediatric Acute Lung Injury and Sepsis Investigators and Pediatric Blood and Marrow Transplant Consortium Joint Working Committees on Supportive Care Guidelines for Management of Veno-Occlusive Disease in Children and Adolescents: Part 2-Focus on Ascites, Fluid and Electrolytes, Renal, and Transfusion Issues

Even though hepatic veno-occlusive disease (VOD) is a potentially fatal complication of hematopoietic cell transplantation (HCT), there is paucity of research on the management of associated multiorgan dysfunction. To help provide standardized care for the management of these patients, the HCT Subgroup of the Pediatric Acute Lung Injury and Sepsis Investigators and the Supportive Care Committee of the Pediatric Blood and Marrow Transplant Consortium, collaborated to develop evidence-based consensus guidelines. After conducting an extensive literature search, in part 2 of this series we discuss the management of fluids and electrolytes, renal dysfunction; ascites, pleural effusion, and transfusion and coagulopathy issues in patients with VOD. We consider the available evidence using the GRADE criteria.

Rationale and design of platelet transfusions in haematopoietic stem cell transplantation: the PATH pilot study

INTRODUCTION

In patients with transient thrombocytopenia being treated with high-dose chemotherapy followed by stem cell rescue-haematopoietic stem cell transplantation (HSCT), prophylactic transfusions are standard therapy to prevent bleeding. However, a recent multicentre trial suggests that prophylactic platelet transfusions in HSCT may not be necessary. Additionally, the potential overuse of platelet products places a burden on a scarce healthcare resource. Moreover, the benefit of prophylactic platelet transfusions to prevent clinically relevant haemorrhage is debatable. Current randomised data compare different thresholds for administering prophylactic platelets or prophylactic versus therapeutic platelet transfusions. An alternative strategy involves prescribing prophylactic antifibrinolytic agents such as tranexamic acid to prevent bleeding.

METHODS AND ANALYSIS

This report describes the design of an open-labelled randomised pilot study comparing the prophylactic use of oral tranexamic acid with platelet transfusions in the setting of autologous HSCT. In 3-5 centres, 100 patients undergoing autologous HSCT will be randomly assigned to either a prophylactic tranexamic acid or prophylactic platelets bleeding prevention strategy-based daily platelet values up to 30 days post-transplant. The study will be stratified by centre and type of transplant. The primary goal is to demonstrate study feasibility while collecting clinical outcomes on (1) WHO and Bleeding Severity Measurement Scale (BSMS), (2) transplant-related mortality, (3) quality of life, (4) length of hospital stay, (5) intensive care unit admission rates, (6) Bearman toxicity scores, (7) incidence of infections, (8) transfusion requirements, (9) adverse reactions and (10) economic analyses.

ETHICS AND DISSEMINATION

This study is funded by a peer-reviewed grant from the Canadian Institutes of Health Research (201 503) and is registered on Clinicaltrials.gov NCT02650791. It has been approved by the Ottawa Health Science Network Research Ethics Board. Study results will presented at national and international conferences. Importantly, the results of this trial will inform the feasibility and conduct of a larger study.

TRIAL REGISTRATION NUMBER

NCT02650791; Pre-results.

Current Status of Platelet Transfusion in Pediatric Patients

Outside the neonatal period, most platelets that are transfused to pediatric patients are given to those who are thrombocytopenic secondary to malignancy and associated therapy and/or hematopoietic progenitor cell transplant, or to those with significant bleeding associated with surgery, especially cardiac surgery. Indications for platelet transfusion, doses, and other practices for children largely mimic adult platelet transfusion protocols because there are few pediatric-specific studies in this area. Pediatric platelet transfusion practices would benefit from focused pediatric research. The appropriate indications and doses for platelet transfusions in oncology, hematopoietic progenitor cell transplant, and cardiac surgery patients need to be determined.

Comparison of different platelet count thresholds to guide administration of prophylactic platelet transfusion for preventing bleeding in people with haematological disorders after myelosuppressive chemotherapy or stem cell transplantation

BACKGROUND

Platelet transfusions are used in modern clinical practice to prevent and treat bleeding in people who are thrombocytopenic due to bone marrow failure. Although considerable advances have been made in platelet transfusion therapy in the last 40 years, some areas continue to provoke debate, especially concerning the use of prophylactic platelet transfusions for the prevention of thrombocytopenic bleeding.This is an update of a Cochrane review first published in 2004, and previously updated in 2012 that addressed four separate questions: prophylactic versus therapeutic-only platelet transfusion policy; prophylactic platelet transfusion threshold; prophylactic platelet transfusion dose; and platelet transfusions compared to alternative treatments. This review has now been split into four smaller reviews looking at these questions individually; this review compares prophylactic platelet transfusion thresholds.

OBJECTIVES

To determine whether different platelet transfusion thresholds for administration of prophylactic platelet transfusions (platelet transfusions given to prevent bleeding) affect the efficacy and safety of prophylactic platelet transfusions in preventing bleeding in people with haematological disorders undergoing myelosuppressive chemotherapy or haematopoietic stem cell transplantation (HSCT).

SEARCH METHODS

We searched for randomised controlled trials (RCTs) in the Cochrane Central Register of Controlled Trials (CENTRAL) (Cochrane Library 2015, Issue 6, 23 July 2015), MEDLINE (from 1946), Embase (from 1974), CINAHL (from 1937), the Transfusion Evidence Library (from 1950), and ongoing trial databases to 23 July 2015.

SELECTION CRITERIA

We included RCTs involving transfusions of platelet concentrates, prepared either from individual units of whole blood or by apheresis, and given to prevent bleeding in people with haematological disorders (receiving myelosuppressive chemotherapy or undergoing HSCT) that compared different thresholds for administration of prophylactic platelet transfusions (low trigger (5 x 10(9)/L); standard trigger (10 x 10(9)/L); higher trigger (20 x 10(9)/L, 30 x 10(9)/L, 50 x 10(9)/L); or alternative platelet trigger (for example platelet mass)).

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by Cochrane.

MAIN RESULTS

Three trials met our predefined inclusion criteria and were included for analysis in the review (499 participants). All three trials compared a standard trigger (10 x 10(9)/L) versus a higher trigger (20 x 10(9)/L or 30 x 10(9)/L). None of the trials compared a low trigger versus a standard trigger or an alternative platelet trigger. The trials were conducted between 1991 and 2001 and enrolled participants from fairly comparable patient populations.The original review contained four trials (658 participants); in the previous update of this review we excluded one trial (159 participants) because fewer than 80% of participants had a haematological disorder. We identified no new trials in this update of the review.Overall, the methodological quality of the studies was low across different outcomes according to GRADE methodology. None of the included studies were at low risk of bias in every domain, and all the included studies had some threats to validity.Three studies reported the number of participants with at least one clinically significant bleeding episode within 30 days from the start of the study. There was no evidence of a difference in the number of participants with a clinically significant bleeding episode between the standard and higher trigger groups (three studies; 499 participants; risk ratio (RR) 1.35, 95% confidence interval (CI) 0.95 to 1.90; low-quality evidence).One study reported the number of days with a clinically significant bleeding event (adjusted for repeated measures). There was no evidence of a difference in the number of days of bleeding per participant between the standard and higher trigger groups (one study; 255 participants; relative proportion of days with World Health Organization Grade 2 or worse bleeding (RR 1.71, 95% CI 0.84 to 3.48, P = 0.162; authors' own results; low-quality evidence).Two studies reported the number of participants with severe or life-threatening bleeding. There was no evidence of any difference in the number of participants with severe or life-threatening bleeding between a standard trigger level and a higher trigger level (two studies; 421 participants; RR 0.99, 95% CI 0.52 to 1.88; low-quality evidence).Only one study reported the time to first bleeding episode. There was no evidence of any difference in the time to the first bleeding episode between a standard trigger level and a higher trigger level (one study; 255 participants; hazard ratio 1.11, 95% CI 0.64 to 1.91; low-quality evidence).Only one study reported on all-cause mortality within 30 days from the start of the study. There was no evidence of any difference in all-cause mortality between standard and higher trigger groups (one study; 255 participants; RR 1.78, 95% CI 0.83 to 3.81; low-quality evidence).Three studies reported on the number of platelet transfusions per participant. Two studies reported on the mean number of platelet transfusions per participant. There was a significant reduction in the number of platelet transfusions per participant in the standard trigger group (two studies, mean difference -2.09, 95% CI -3.20 to -0.99; low-quality evidence).One study reported on the number of transfusion reactions. There was no evidence to demonstrate any difference in transfusion reactions between the standard and higher trigger groups (one study; 79 participants; RR 0.07, 95% CI 0.00 to 1.09).None of the studies reported on quality of life.

AUTHORS' CONCLUSIONS

In people with haematological disorders who are thrombocytopenic due to myelosuppressive chemotherapy or HSCT, we found low-quality evidence that a standard trigger level (10 x 10(9)/L) is associated with no increase in the risk of bleeding when compared to a higher trigger level (20 x 10(9)/L or 30 x 10(9)/L). There was low-quality evidence that a standard trigger level is associated with a decreased number of transfusion episodes when compared to a higher trigger level (20 x 10(9)/L or 30 x 10(9)/L).Findings from this review were based on three studies and 499 participants. Without further evidence, it is reasonable to continue with the current practice of administering prophylactic platelet transfusions using the standard trigger level (10 x 10(9)/L) in the absence of other risk factors for bleeding.

Different doses of prophylactic platelet transfusion for preventing bleeding in people with haematological disorders after myelosuppressive chemotherapy or stem cell transplantation

BACKGROUND

Platelet transfusions are used in modern clinical practice to prevent and treat bleeding in people who are thrombocytopenic due to bone marrow failure. Although considerable advances have been made in platelet transfusion therapy in the last 40 years, some areas continue to provoke debate, especially concerning the use of prophylactic platelet transfusions for the prevention of thrombocytopenic bleeding.This is an update of a Cochrane review first published in 2004, and updated in 2012 that addressed four separate questions: prophylactic versus therapeutic-only platelet transfusion policy; prophylactic platelet transfusion threshold; prophylactic platelet transfusion dose; and platelet transfusions compared to alternative treatments. This review has now been split into four smaller reviews; this review compares different platelet transfusion doses.

OBJECTIVES

To determine whether different doses of prophylactic platelet transfusions (platelet transfusions given to prevent bleeding) affect their efficacy and safety in preventing bleeding in people with haematological disorders undergoing myelosuppressive chemotherapy with or without haematopoietic stem cell transplantation (HSCT).

SEARCH METHODS

We searched for randomised controlled trials in the Cochrane Central Register of Controlled Trials (CENTRAL) (Cochrane Library 2015, Issue 6), MEDLINE (from 1946), Embase (from 1974), CINAHL (from 1937), the Transfusion Evidence Library (from 1950), and ongoing trial databases to 23 July 2015.

SELECTION CRITERIA

Randomised controlled trials involving transfusions of platelet concentrates, prepared either from individual units of whole blood or by apheresis, and given to prevent bleeding in people with malignant haematological disorders or undergoing HSCT that compared different platelet component doses (low dose 1.1 x 10(11)/m(2) ± 25%, standard dose 2.2 x 10(11)/m(2) ± 25%, high dose 4.4 x 10(11)/m(2) ± 25%).

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by The Cochrane Collaboration.

MAIN RESULTS

We included seven trials (1814 participants) in this review; six were conducted during one course of treatment (chemotherapy or HSCT).Overall the methodological quality of studies was low to moderate across different outcomes according to GRADE methodology. None of the included studies were at low risk of bias in every domain, and all the included studies had some threats to validity.Five studies reported the number of participants with at least one clinically significant bleeding episode within 30 days from the start of the study. There was no difference in the number of participants with a clinically significant bleeding episode between the low-dose and standard-dose groups (four studies; 1170 participants; risk ratio (RR) 1.04, 95% confidence interval (CI) 0.95 to 1.13; moderate-quality evidence); low-dose and high-dose groups (one study; 849 participants; RR 1.02, 95% CI 0.93 to 1.11; moderate-quality evidence); or high-dose and standard-dose groups (two studies; 951 participants; RR 1.02, 95% CI 0.93 to 1.11; moderate-quality evidence).Three studies reported the number of days with a clinically significant bleeding event per participant. There was no difference in the number of days of bleeding per participant between the low-dose and standard-dose groups (two studies; 230 participants; mean difference -0.17, 95% CI -0.51 to 0.17; low quality evidence). One study (855 participants) showed no difference in the number of days of bleeding per participant between high-dose and standard-dose groups, or between low-dose and high-dose groups (849 participants).Three studies reported the number of participants with severe or life-threatening bleeding. There was no difference in the number of participants with severe or life-threatening bleeding between a low-dose and a standard-dose platelet transfusion policy (three studies; 1059 participants; RR 1.33, 95% CI 0.91 to 1.92; low-quality evidence); low-dose and high-dose groups (one study; 849 participants; RR 1.20, 95% CI 0.82 to 1.77; low-quality evidence); or high-dose and standard-dose groups (one study; 855 participants; RR 1.11, 95% CI 0.73 to 1.68; low-quality evidence).Two studies reported the time to first bleeding episodes; we were unable to perform a meta-analysis. Both studies (959 participants) individually found that the time to first bleeding episode was either the same, or longer, in the low-dose group compared to the standard-dose group. One study (855 participants) found that the time to the first bleeding episode was the same in the high-dose group compared to the standard-dose group.Three studies reported all-cause mortality within 30 days from the start of the study. There was no difference in all-cause mortality between treatment arms (low-dose versus standard-dose: three studies; 1070 participants; RR 2.04, 95% CI 0.70 to 5.93; low-quality evidence; low-dose versus high-dose: one study; 849 participants; RR 1.33, 95% CI 0.50 to 3.54; low-quality evidence; and high-dose versus standard-dose: one study; 855 participants; RR 1.71, 95% CI 0.51 to 5.81; low-quality evidence).Six studies reported the number of platelet transfusions; we were unable to perform a meta-analysis. Two studies (959 participants) out of three (1070 participants) found that a low-dose transfusion strategy led to more transfusion episodes than a standard-dose. One study (849 participants) found that a low-dose transfusion strategy led to more transfusion episodes than a high-dose strategy. One study (855 participants) out of three (1007 participants) found no difference in the number of platelet transfusions between the high-dose and standard-dose groups.One study reported on transfusion reactions. This study's authors suggested that a high-dose platelet transfusion strategy may lead to a higher rate of transfusion-related adverse events.None of the studies reported quality-of-life.

AUTHORS' CONCLUSIONS

In haematology patients who are thrombocytopenic due to myelosuppressive chemotherapy or HSCT, we found no evidence to suggest that a low-dose platelet transfusion policy is associated with an increased bleeding risk compared to a standard-dose or high-dose policy, or that a high-dose platelet transfusion policy is associated with a decreased risk of bleeding when compared to a standard-dose policy.A low-dose platelet transfusion strategy leads to an increased number of transfusion episodes compared to a standard-dose strategy. A high-dose platelet transfusion strategy does not decrease the number of transfusion episodes per participant compared to a standard-dose regimen, and it may increase the number of transfusion-related adverse events.Findings from this review would suggest a change from current practice, with low-dose platelet transfusions used for people receiving in-patient treatment for their haematological disorder and high-dose platelet transfusion strategies not being used routinely.

The association between platelet transfusion and idiopathic pneumonia syndrome is unaffected by platelet product type

BACKGROUND

Methods used to produce platelet (PLT) components, pooling of PLT-rich plasma (PRP-PLT) and apheresis (AP-PLT), may variably contribute to the pathogenesis and severity of idiopathic pneumonia syndrome (IPS).

STUDY DESIGN AND METHODS

We performed a retrospective cohort study of 906 allogeneic hematopoietic cell transplant recipients to examine associations between PLT product type and risks of developing IPS and dying after IPS onset. Proportional hazards models included separate terms for the sum of all PLT transfusions and the sum of PRP-PLT units received in the 3 or 7 days before IPS onset. Similarly constructed models analyzed the outcome of time to death after IPS onset. All analyses were adjusted for known IPS risk factors.

RESULTS

Patients received a median of three PRP-PLT transfusions (interquartile range [IQR], 0-6) and five AP-PLT transfusions (IQR, 1-13) while at risk for IPS. Seventy-five patients (8%) developed IPS by Posttransplant Day 120. The proportion of PRP-PLT transfusions was not associated with risk of developing IPS (3-day hazard ratio [HR] 0.98, 95% CI 0.74-1.29, p = 0.86; 7-day HR 1.00, 95% CI 0.86-1.15, p = 0.95) or dying after IPS onset (3-day HR 0.99, 95% CI 0.75-1.31, p = 0.97; 7-day HR 0.98, 95% CI 0.78-1.12, p = 0.47).

CONCLUSION

The association between PLT transfusions and risk of developing IPS or dying after IPS onset does not differ according to PLT product type. Further research is required to identify potentially modifiable steps in PLT component production that contribute to IPS.

A therapeutic-only versus prophylactic platelet transfusion strategy for preventing bleeding in patients with haematological disorders after myelosuppressive chemotherapy or stem cell transplantation

BACKGROUND

Platelet transfusions are used in modern clinical practice to prevent and treat bleeding in thrombocytopenic patients with bone marrow failure. Although considerable advances have been made in platelet transfusion therapy in the last 40 years, some areas continue to provoke debate, especially concerning the use of prophylactic platelet transfusions for the prevention of thrombocytopenic bleeding.This is an update of a Cochrane review first published in 2004 and updated in 2012 that addressed four separate questions: therapeutic-only versus prophylactic platelet transfusion policy; prophylactic platelet transfusion threshold; prophylactic platelet transfusion dose; and platelet transfusions compared to alternative treatments. We have now split this review into four smaller reviews looking at these questions individually; this review is the first part of the original review.

OBJECTIVES

To determine whether a therapeutic-only platelet transfusion policy (platelet transfusions given when patient bleeds) is as effective and safe as a prophylactic platelet transfusion policy (platelet transfusions given to prevent bleeding, usually when the platelet count falls below a given trigger level) in patients with haematological disorders undergoing myelosuppressive chemotherapy or stem cell transplantation.

SEARCH METHODS

We searched for randomised controlled trials (RCTs) in the Cochrane Central Register of Controlled Trials (Cochrane Library 2015, Issue 6), MEDLINE (from 1946), Embase (from 1974), CINAHL (from 1937), the Transfusion Evidence Library (from 1950) and ongoing trial databases to 23 July 2015.

SELECTION CRITERIA

RCTs involving transfusions of platelet concentrates prepared either from individual units of whole blood or by apheresis, and given to prevent or treat bleeding in patients with malignant haematological disorders receiving myelosuppressive chemotherapy or undergoing HSCT.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by The Cochrane Collaboration.

MAIN RESULTS

We identified seven RCTs that compared therapeutic platelet transfusions to prophylactic platelet transfusions in haematology patients undergoing myelosuppressive chemotherapy or HSCT. One trial is still ongoing, leaving six trials eligible with a total of 1195 participants. These trials were conducted between 1978 and 2013 and enrolled participants from fairly comparable patient populations. We were able to critically appraise five of these studies, which contained separate data for each arm, and were unable to perform quantitative analysis on one study that did not report the numbers of participants in each treatment arm.Overall the quality of evidence per outcome was low to moderate according to the GRADE approach. None of the included studies were at low risk of bias in every domain, and all the studies identified had some threats to validity. We deemed only one study to be at low risk of bias in all domains other than blinding.Two RCTs (801 participants) reported at least one bleeding episode within 30 days of the start of the study. We were unable to perform a meta-analysis due to considerable statistical heterogeneity between studies. The statistical heterogeneity seen may relate to the different methods used in studies for the assessment and grading of bleeding. The underlying patient diagnostic and treatment categories also appeared to have some effect on bleeding risk. Individually these studies showed a similar effect, that a therapeutic-only platelet transfusion strategy was associated with an increased risk of clinically significant bleeding compared with a prophylactic platelet transfusion policy. Number of days with a clinically significant bleeding event per participant was higher in the therapeutic-only group than in the prophylactic group (one RCT; 600 participants; mean difference 0.50, 95% confidence interval (CI) 0.10 to 0.90; moderate-quality evidence). There was insufficient evidence to determine whether there was any difference in the number of participants with severe or life-threatening bleeding between a therapeutic-only transfusion policy and a prophylactic platelet transfusion policy (two RCTs; 801 participants; risk ratio (RR) 4.91, 95% CI 0.86 to 28.12; low-quality evidence). Two RCTs (801 participants) reported time to first bleeding episode. As there was considerable heterogeneity between the studies, we were unable to perform a meta-analysis. Both studies individually found that time to first bleeding episode was shorter in the therapeutic-only group compared with the prophylactic platelet transfusion group.There was insufficient evidence to determine any difference in all-cause mortality within 30 days of the start of the study using a therapeutic-only platelet transfusion policy compared with a prophylactic platelet transfusion policy (two RCTs; 629 participants). Mortality was a rare event, and therefore larger studies would be needed to establish the effect of these alternative strategies. There was a clear reduction in the number of platelet transfusions per participant in the therapeutic-only arm (two RCTs, 991 participants; standardised mean reduction of 0.50 platelet transfusions per participant, 95% CI -0.63 to -0.37; moderate-quality evidence). None of the studies reported quality of life. There was no evidence of any difference in the frequency of adverse events, such as transfusion reactions, between a therapeutic-only and prophylactic platelet transfusion policy (two RCTs; 991 participants; RR 1.02, 95% CI 0.62 to 1.68), although the confidence intervals were wide.

AUTHORS' CONCLUSIONS

We found low- to moderate-grade evidence that a therapeutic-only platelet transfusion policy is associated with increased risk of bleeding when compared with a prophylactic platelet transfusion policy in haematology patients who are thrombocytopenic due to myelosuppressive chemotherapy or HSCT. There is insufficient evidence to determine any difference in mortality rates and no evidence of any difference in adverse events between a therapeutic-only platelet transfusion policy and a prophylactic platelet transfusion policy. A therapeutic-only platelet transfusion policy is associated with a clear reduction in the number of platelet components administered.

Platelet transfusion: a clinical practice guideline from the AABB

BACKGROUND

The AABB (formerly, the American Association of Blood Banks) developed this guideline on appropriate use of platelet transfusion in adult patients.

METHODS

These guidelines are based on a systematic review of randomized, clinical trials and observational studies (1900 to September 2014) that reported clinical outcomes on patients receiving prophylactic or therapeutic platelet transfusions. An expert panel reviewed the data and developed recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework.

RECOMMENDATION 1

The AABB recommends that platelets should be transfused prophylactically to reduce the risk for spontaneous bleeding in hospitalized adult patients with therapy-induced hypoproliferative thrombocytopenia. The AABB recommends transfusing hospitalized adult patients with a platelet count of 10 × 109 cells/L or less to reduce the risk for spontaneous bleeding. The AABB recommends transfusing up to a single apheresis unit or equivalent. Greater doses are not more effective, and lower doses equal to one half of a standard apheresis unit are equally effective. (Grade: strong recommendation; moderate-quality evidence).

RECOMMENDATION 2

The AABB suggests prophylactic platelet transfusion for patients having elective central venous catheter placement with a platelet count less than 20 × 109 cells/L. (Grade: weak recommendation; low-quality evidence).

RECOMMENDATION 3

The AABB suggests prophylactic platelet transfusion for patients having elective diagnostic lumbar puncture with a platelet count less than 50 × 109 cells/L. (Grade: weak recommendation; very-low-quality evidence).

RECOMMENDATION 4

The AABB suggests prophylactic platelet transfusion for patients having major elective nonneuraxial surgery with a platelet count less than 50 × 109 cells/L. (Grade: weak recommendation; very-low-quality evidence).

RECOMMENDATION 5

The AABB recommends against routine prophylactic platelet transfusion for patients who are nonthrombocytopenic and have cardiac surgery with cardiopulmonary bypass. The AABB suggests platelet transfusion for patients having bypass who exhibit perioperative bleeding with thrombocytopenia and/or evidence of platelet dysfunction. (Grade: weak recommendation; very-low-quality evidence).

RECOMMENDATION 6

The AABB cannot recommend for or against platelet transfusion for patients receiving antiplatelet therapy who have intracranial hemorrhage (traumatic or spontaneous). (Grade: uncertain recommendation; very-low-quality evidence).

Platelet transfusion goals in oncology patients

Despite the advances in platelet component preparation and transfusion support over the years, platelet products remain a limited resource due to their short (5 day) shelf life, and therefore their optimal use in the non-bleeding thrombocytopenic patient continue to draw much attention. There have been a number of national and international guidelines for platelet transfusion therapy in patients with hematologic diseases, some within the last 1-2 years that have incorporated key randomized controlled trials (RCTs) which address issues, such as the optimal platelet dose, the most appropriate threshold for prophylactic platelet transfusions, and whether prophylactic platelet transfusions are superior to therapeutic-only platelet transfusion practices for the prevention life-threatening bleeding in patients with hypoproliferative thrombocytopenia. This review highlights key RCTs and recent systematic reviews focused on optimal platelet transfusion therapy in adult and pediatric patients with hypoproliferative thrombocytopenia secondary to chemotherapy or hematopoietic stem cell transplant (HSCT), discuss how recent innovations in platelet component processing may affect transfusion efficiency, and introduce renewed concepts on adjuvant therapies to prevent bleeding in the hypoproliferative thrombocytopenic patient.

Hemostatic function and transfusion efficacy of apheresis platelet concentrates treated with gamma irradiation in use for thrombocytopenic patients

BACKGROUND

During the transfusion of blood components, the transfer of allogeneic donor white blood cells (WBCs) can mediate transfusion-associated graft-versus-host disease (TA-GVHD). To minimize the reaction, exposure of blood products to gamma irradiation is currently the standard of care. The aim of our study was to evaluate and compare hemostatic function, transfusion efficacy, and safety of gamma-irradiated single-donor apheresis platelet concentrates (PCs) and of conventional non-irradiated PCs in patients with chemotherapy-induced thrombocytopenia.

METHODS

20 double-dose single-donor leukoreduced PCs were split in two identical units; one was gamma-irradiated with 25 Gy (study arm A) and the other remains non-irradiated (study arm B). Both units were stored under equal conditions. Hematologic patients were randomly assigned to receive gamma-irradiated or conventional non-irradiated PCs. Hemostatic function was evaluated by thrombelastography (TEG). TEG measurements were taken pre transfusion and 1 and 24 h post transfusion. TEG profiles were measured, noting the time to initiate clotting (R), the angle of clot formation (α), and the maximum amplitude (clot strength (MA)). Whole blood samples were collected from these thrombocytopenic patients at 1 and 24 h for PLT count increments (CIs) and corrected count increments (CCIs) with assessments of transfusion efficacy. Time to next PLT transfusion, transfusion requirement of RBCs, active bleeding, and adverse events (AEs), were analyzed.

RESULTS

No differences could be found in hemostatic function parameters (MA, R, and α) between study arms A and B (all p values > 0.096) pre transfusion as well as 1 and 24 h post transfusion. No differences between study arms A and B were observed for mean (± standard deviation (SD)) 1-hour CCI (12.83 ± 6.33 vs. 11.59 ± 5.97) and 24-hour CCI (6.56 ± 4.10 vs. 5.76 ± 4.05). Mean 1-hour CI and 24-hour CI were not significantly different in both study arms (p = 0.254 and p = 0.242 respectively). Median time to the next PC transfusion after study PC was not significantly different between groups: (2.4 vs. 2.2 days, p = 0.767). No differences could be found in transfusion requirement of red blood cells (p = 0.744) between both study arms. There were also no regarding bleeding, adverse events, and acute transfusion reaction(s).

CONCLUSIONS

This study confirms safety of gamma-irradiated PCs for treatment thrombocytopenia. Hemostatic function, transfusion efficacy, bleeding, and safety of single-donor apheresis PCs treated with gamma irradiation versus untreated control PCs are comparable.

A pilot study to assess the hemostatic function of pathogen-reduced platelets in patients with thrombocytopenia

BACKGROUND

Platelet (PLT) support is critical to the care of patients with thrombocytopenia, but allogeneic transfusions carry risk. Pathogen reduction mitigates some transfusion risks, but effects on PLT function remain a concern. This clinical pilot study assessed the effect of pathogen reduction technology with riboflavin plus ultraviolet light using thrombelastography (TEG).

STUDY DESIGN AND METHODS

This prospective, randomized, crossover study compared Mirasol-treated (MIR) and standard reference (REF) PLT transfusions. PLT counts and TEG measurements were taken at pretransfusion and 1- and 24-hour-posttransfusion time points. The primary outcome measure was the pretransfusion to 1-hour-posttransfusion change in maximum amplitude (ΔMA(1 hr)). Secondary endpoints included ΔMA among other time points, relative MA, and the PLT count-MA correlation.

RESULTS

Of 16 enrolled patients, one withdrew before study treatment and three did not require two transfusions, leaving 12 patients in the efficacy analyses (seven MIR-REF, five REF-MIR). ΔMA(1 hr) (mean ± SD) was 10.60 ± 6.47 mm for MIR and 14.33 ± 5.38 mm for REF (p = 0.20, n = 10). ΔMA(24hr) was 9.49 ± 7.94 for MIR and 7.13 ± 3.08 for REF (p = 0.38, n = 9); ΔMA(24hr-1 hr) was -1.11 ± 2.95 for MIR and -7.20 ± 4.81 for REF (p = 0.016, n = 8). MA values for MIR and REF correlated with the log of PLT count (rMIR = 0.6901, rREF = 0.7399).

CONCLUSION

TEG is sensitive to changes in hemostatic function resulting from a single PLT transfusion. MIR and REF provided similar increments in hemostatic function in the immediate posttransfusion period and at 24 hours. A significant difference detected for ΔMA(24hr-1 hr) suggests different PLT clearance mechanisms. The relationship of these variables to clinically meaningful outcomes, for example, bleeding events or transfusion requirements, has yet to be determined.

Measuring bleeding as an outcome in clinical trials of prophylactic platelet transfusions

A 12-year-old girl with acute myeloid leukemia has completed her third cycle of chemotherapy and is in the hospital awaiting count recovery. Her platelet count today is 15 000 and, based on your institution's protocol, she should receive a prophylactic platelet transfusion. She has a history of allergic reactions to platelet transfusions and currently has no bleeding symptoms. The patient's mother questions the necessity of today's transfusion and asks what her daughter's risk of bleeding would be if the count is allowed to decrease lower before transfusing. You perform a literature search regarding the risk of bleeding with differing regimens for prophylactic platelet transfusions.

The observation of bleeding complications in haemato-oncological patients: stringent watching, relevant reporting

BACKGROUND

The reported percentage of haemato-oncological patients experiencing bleeding complications is highly variable, ranging from 5 to 70%, posing a major problem for comparison of clinical platelet transfusion trials using bleeding complications as a primary endpoint. In a pilot study we assessed the impact of the design of scoring of bleeding on the percentage of patients with WHO grade 2 or higher bleeding grades.

STUDY DESIGN AND METHODS

We performed a prospective, observational study using a rigorous bleeding observation system in thrombocytopenic patients with haemato-oncological disorders. Endpoints of the study were the percentage of patients and days with bleeding WHO grade ≥ 2 comparing designs in which skin bleeding represent a continuation of a previous bleed or a new bleed.

RESULTS

In four participating hospitals 64 patients suffering 870 evaluable thrombocytopenic days (platelet count < 80 × 10(9) L(-1)) were included. At least one episode of bleeding grade ≥ 2 occurred in 36 patients (56%). Most grade 2 bleeding complications occurred mucocutaneously. The percentage of days with bleeding of grade ≥ 2 was 16% but decreases to 8% when only newly developed skin bleeding was included.

CONCLUSION

Rigorous daily observation results in a bleeding incidence that is comparable to recent reportings applying the same method. The results of this study show that censoring for stable skin bleeding has a profound effect on bleeding incidence per day. The clinical relevance of rigorous or clinically judged bleeding scores as an endpoint remains to be defined.

Prophylactic platelet transfusion for prevention of bleeding in patients with haematological disorders after chemotherapy and stem cell transplantation

BACKGROUND

Platelet transfusions are used in modern clinical practice to prevent and treat bleeding in thrombocytopenic patients with bone marrow failure. Although considerable advances have been made in platelet transfusion therapy in the last 40 years, some areas continue to provoke debate especially concerning the use of prophylactic platelet transfusions for the prevention of thrombocytopenic bleeding.

OBJECTIVES

To determine the most effective use of platelet transfusion for the prevention of bleeding in patients with haematological disorders undergoing chemotherapy or stem cell transplantation.

SEARCH METHODS

This is an update of a Cochrane review first published in 2004. We searched for randomised controlled trials (RCTs) in the Cochrane Central Register of Controlled Trials (CENTRAL Issue 4, 2011), MEDLINE (1950 to Nov 2011), EMBASE (1980 to Nov 2011) and CINAHL (1982 to Nov 2011), using adaptations of the Cochrane RCT search filter, the UKBTS/SRI Transfusion Evidence Library, and ongoing trial databases to 10 November 2011.

SELECTION CRITERIA

RCTs involving transfusions of platelet concentrates, prepared either from individual units of whole blood or by apheresis, and given to prevent bleeding in patients with haematological disorders. Four different types of prophylactic platelet transfusion trial were included.

DATA COLLECTION AND ANALYSIS

In the original review one author initially screened all electronically derived citations and abstracts of papers, identified by the review search strategy, for relevancy. Two authors performed this task in the updated review. Two authors independently assessed the full text of all potentially relevant trials for eligibility. Two authors completed data extraction independently. We requested missing data from the original investigators as appropriate.

MAIN RESULTS

There were 18 trials that were eligible for inclusion, five of these were still ongoing.Thirteen completed published trials (2331 participants) were included for analysis in the review. The original review contained nine trials (718 participants). This updated review includes six new trials (1818 participants).Two trials (205 participants) in the original review are now excluded because fewer than 80% of participants had a haematological disorder.The four different types of prophylactic platelet transfusion trial, that were the focus of this review, were included within these thirteen trials.Three trials compared prophylactic platelet transfusions versus therapeutic-only platelet transfusions. There was no statistical difference between the number of participants with clinically significant bleeding in the therapeutic and prophylactic arms but the confidence interval was wide (RR 1.66; 95% CI 0.9 to 3.04).The time taken for a clinically significant bleed to occur was longer in the prophylactic platelet transfusion arm. There was a clear reduction in platelet transfusion usage in the therapeutic arm. There was no statistical difference between the number of participants in the therapeutic and prophylactic arms with platelet refractoriness, the only adverse event reported.Three trials compared different platelet count thresholds to trigger administration of prophylactic platelet transfusions. No statistical difference was seen in the number of participants with clinically significant bleeding (RR 1.35; 95% CI 0.95 to 1.9), however, this type of bleeding occurred on fewer days in the group of patients transfused at a higher platelet count threshold (RR 1.72; 95% CI 1.33 to 2.22).The lack of a difference seen for the number of participants with clinically significant bleeding may be due to the studies, in combination, having insufficient power to demonstrate a difference, or due to masking of the effect by a higher number of protocol violations in the groups of patients with a lower platelet count threshold. Using a lower platelet count threshold led to a significant reduction in the number of platelet transfusions used. There were no statistical differences in the number of adverse events reported between the two groups.Six trials compared different doses of prophylactic platelet transfusions. There was no evidence to suggest that using a lower platelet transfusion dose increased: the number of participants with clinically significant (WHO grade 2 or above) (RR 1.02; 95% CI 0.93 to 1.11), or life-threatening (WHO grade 4) bleeding (RR 1.87; 95% CI 0.86 to 4.08). A higher platelet transfusion dose led to a reduction in the number of platelet transfusion episodes, but an increase in total platelet utilisation. Only one adverse event, wheezing after transfusion, had a significantly higher incidence when standard and high dose transfusions were compared but this difference was not seen when low dose and high dose transfusions were compared. It is therefore likely to be a type I error (false positive).One small trial compared prophylactic platelet transfusions versus platelet-poor plasma. The risk of a significant bleed was decreased in the prophylactic platelet transfusion arm (RR 0.47; 95% CI 0.23 to 0.95) and this was statistically significant.All studies had threats to validity; the majority of these were due to methodology of the studies not being described in adequate detail.Although it was not the main focus of the review, it was interesting to note that in one of the pre-specified sub-group analyses (treatment type) two studies showed that patients receiving an autologous transplant have a lower risk of bleeding than patients receiving intensive chemotherapy or an allogeneic transplant (RR 0.73, 95% CI 0.65 to 0.82).

AUTHORS' CONCLUSIONS

These conclusions refer to the four different types of platelet transfusion trial separately. Firstly, there is no evidence that a prophylactic platelet transfusion policy prevents bleeding. Two large trials comparing a therapeutic versus prophylactic platelet transfusion strategy, that have not yet been published, should provide important new data on this comparison. Secondly, there is no evidence, at the moment, to suggest a change from the current practice of using a platelet count of 10 x 10(9)/L. However, the evidence for a platelet count threshold of 10 x 10(9)/L being equivalent to 20 x 10(9)/L is not as definitive as it would first appear and further research is required. Thirdly, platelet dose does not affect the number of patients with significant bleeding, but whether it affects number of days each patient bleeds for is as yet undetermined. There is no evidence that platelet dose affects the incidence of WHO grade 4 bleeding.Prophylactic platelet transfusions were more effective than platelet-poor plasma at preventing bleeding.

New thoughts on the correct dosing of prophylactic platelet transfusions to prevent bleeding

PURPOSE OF REVIEW

Recent studies have evaluated the effects of platelet dose on hemostasis.

RECENT FINDINGS

As long as a critical level of 5000  platelets/μl is maintained, platelet counts do not affect bleeding. The risk of WHO grade 2 or greater bleeding was 25% on days with morning platelet counts of less than 5000/μl and was 17% at platelet counts between 6000 and 80 000/μl (P < 0.001). Therefore, it is not surprising that platelet doses of half to twice the usual dose of 2.2 × 10(11)  platelets/transfusion/body surface area (BSA) do not affect any bleeding grade. However, the risk of grade 2 or greater bleeding is higher in patients receiving an allogeneic hematopoietic stem cell transplant (HSCT, 79%) versus those receiving chemotherapy for hematologic malignancies (73%) or those receiving an autologous HSCT (57%) (P < 0.001 for the latter versus the first two groups). In contrast, in children under 18, the risk of bleeding was higher in all treatment groups than in adults, particularly for children receiving autologous HSCT (93 to 83% based on increasing patient age). However, for none of these treatment categories did platelet dose affect bleeding risk.

SUMMARY

Platelet doses in ranges between half to twice the usual dose of 2.2 × 10(11)  platelets/transfusion/BSA have no affect on WHO bleeding grades.

Platelet dose for prophylactic platelet transfusions

Although guidelines exist to deal with some aspects of platelet transfusion practice, many important clinical issues have not been addressed in large randomized controlled trials (RCTs). Slichter et al. conducted a RCT of prophylactic platelet transfusions to determine the effects of the dose of platelets on clinical signs of bleeding, the use of platelet and red cell transfusions, changes in the recipient's post-transfusion platelet count, days to next transfusion and adverse events (Effects of Prophylactic Platelet Dose on Transfusion Outcomes [PLADO] trial). The primary end point of the study (i.e., the percentage of patients in each group with at least one episode of bleeding of grade 2 or higher according to the WHO criteria) was not significantly different (71, 69 and 70% of patients in the low-, medium- and high-dose group, respectively). According to these data, one can conclude that the dose of platelets transfused has no significant effect on the incidence of bleeding in patients with hypoproliferative thrombocytopenia and platelet counts no greater than 10 × 10⁹/l.

Current practice and future directions for optimization of platelet transfusions in patients with severe therapy-induced cytopenia

Platelet transfusions are mainly used for patients with thrombocytopenia due to bone marrow failure, especially cancer patients developing severe chemotherapy-induced thrombocytopenia (e.g. patients with acute leukemia or other hematologic malignancies). A prophylactic transfusion strategy is now generally accepted in developed countries. Some clinical data, however, support the use of a therapeutic transfusion strategy at least for certain subsets of these patients. Several methodological approaches can then be used to evaluate the outcome of platelet transfusions, including peripheral blood platelet increments and bleeding assessments. Several factors will influence the efficiency of platelet transfusions; fever and ongoing hemorrhage are among the most important patient-dependent factors, but the number and quality of the transfused platelets are also important. The quality of transfused platelets can be evaluated by analyzing platelet activation, metabolism or senescence/apoptosis. Only evaluation of metabolism is included in international guidelines, but high-throughput methods for evaluation of activation and senescence/apoptosis are available and should be incorporated into routine clinical practice if future studies demonstrate that they reflect clinically relevant platelet characteristics. Finally, platelet transfusions have additional biological effects that may cause immunomodulation or altered angioregulation; at present it is not known whether these effects will influence the long-time prognosis of cancer patients. Thus, several questions with regard to the optimal use of platelet transfusions in cancer patients still need to be answered.

A systematic assessment of the quality of reporting for platelet transfusion studies

BACKGROUND

As evidence-based medicine assumes increasing importance, there is a need for high-quality reporting of clinical studies. A recent review of clinical platelet (PLT) studies indicated variability in reporting. We undertook a critical analysis of PLT transfusion studies to determine the quality of reporting.

STUDY DESIGN AND METHODS

A systematic MEDLINE search for clinical studies of PLT transfusion was performed to identify articles. Relevant observational studies (OBS) were critiqued using the STROBE checklist and randomized controlled clinical trials (RCTs) using the CONSORT checklist. Studies were further evaluated with a PLT-specific checklist developed by the authors. Observations were analyzed descriptively and using Pareto analysis.

RESULTS

A total of 772 articles were identified by the search. Eighty-six articles (23 RCTs and 63 OBS) met eligibility criteria. All RCTs, and a similar number of OBS (24), were randomly selected for analysis. Studies reported the scientific background and rationale, key results, and outcomes. OBS frequently did not consider bias and confounders. RCTs frequently did not explain bias, interim analyses, stopping rules, success of blinding, or weaknesses of multiple analyses. The PLT-specific critique found many studies adequately reported basics of the PLT product, PLT increment, and transfusion reactions. Studies frequently failed to report specific details of PLT compatibility, details of product preparation, and use of other blood products.

CONCLUSION

Recently published articles of clinical PLT transfusion share common strengths and weaknesses. The quality of reporting may be improved by providing guidelines to authors and journal editors that list the essential elements of a well-reported clinical study of PLT transfusion.

Dose of prophylactic platelet transfusions and prevention of hemorrhage

BACKGROUND

We conducted a trial of prophylactic platelet transfusions to evaluate the effect of platelet dose on bleeding in patients with hypoproliferative thrombocytopenia.

METHODS

We randomly assigned hospitalized patients undergoing hematopoietic stem-cell transplantation or chemotherapy for hematologic cancers or solid tumors to receive prophylactic platelet transfusions at a low dose, a medium dose, or a high dose (1.1x10(11), 2.2x10(11), or 4.4x10(11) platelets per square meter of body-surface area, respectively), when morning platelet counts were 10,000 per cubic millimeter or lower. Clinical signs of bleeding were assessed daily. The primary end point was bleeding of grade 2 or higher (as defined on the basis of World Health Organization criteria).

RESULTS

In the 1272 patients who received at least one platelet transfusion, the primary end point was observed in 71%, 69%, and 70% of the patients in the low-dose group, the medium-dose group, and the high-dose group, respectively (differences were not significant). The incidences of higher grades of bleeding, and other adverse events, were similar among the three groups. The median number of platelets transfused was significantly lower in the low-dose group (9.25x10(11)) than in the medium-dose group (11.25x10(11)) or the high-dose group (19.63x10(11)) (P=0.002 for low vs. medium, P<0.001 for high vs. low and high vs. medium), but the median number of platelet transfusions given was significantly higher in the low-dose group (five, vs. three in the medium-dose and three in the high-dose group; P<0.001 for low vs. medium and low vs. high). Bleeding occurred on 25% of the study days on which morning platelet counts were 5000 per cubic millimeter or lower, as compared with 17% of study days on which platelet counts were 6000 to 80,000 per cubic millimeter (P<0.001).

CONCLUSIONS

Low doses of platelets administered as a prophylactic transfusion led to a decreased number of platelets transfused per patient but an increased number of transfusions given. At doses between 1.1x10(11) and 4.4x10(11) platelets per square meter, the number of platelets in the prophylactic transfusion had no effect on the incidence of bleeding. (ClinicalTrials.gov number, NCT00128713.)

Prediction of fatal intracranial hemorrhage in patients with acute myeloid leukemia

BACKGROUND

Intracranial hemorrhage (ICH) is the second leading cause of mortality in patients with acute myeloid leukemia (AML). However, the prognostic factors for ICH in AML patients are still under investigation.

PATIENTS AND METHODS

A total of 841 AML patients admitted to the Department of Internal Medicine from January 1995 to December 2007 were enrolled in this study.

RESULTS

There were 51 patients with ICH, median age of 51 (range 17-86), including 12 patients diagnosed as acute promyelocytic leukemia. Forty-three patients were refractory/relapsed status. ICH was localized in the supratentorium (44 cases), basal ganglion (9), cerebellum (5), and brainstem (4). Twenty-one patients had multiple sites. Thirty-eight patients had intraparenchymal hemorrhage, 16 subarachnoid hemorrhage (SAH), 10 subdural hemorrhage, and one epidural hemorrhage (EDH). Hemorrhage ruptured into the ventricles in 13 patients. Thirty-four patients (67%) died of ICH within 30 days of diagnosis. Multivariate analysis revealed four independent prognostic factors, prolonged prothrombin time international normalized ratio >1.5 (P < 0.001), brainstem hemorrhage (P = 0.001), SAH (P = 0.017), and EDH (P = 0.014). Other clinico-laboratory data had no impact on 30-day survival.

CONCLUSIONS

ICH has high morbidity and mortality in AML. Early detection and aggressive correction coagulopathy may prevent the catastrophic event. Prompt image study for locations and types of ICH can predict outcomes.

A randomized controlled trial comparing standard- and low-dose strategies for transfusion of platelets (SToP) to patients with thrombocytopenia

A noninferiority study was performed comparing low-dose and standard-dose prophylactic platelet transfusions. A double-blind randomized controlled trial (RCT) was performed in 6 sites in 3 countries. Thrombocytopenic adults requiring prophylactic platelet transfusion were randomly allocated to standard-dose (300-600 × 109 platelets/product) or low-dose (150- < 300 × 109 platelets/product) platelets. The primary outcome (World Health Organization [WHO] bleeding ≥ grade 2) was assessed daily through clinical examination, patient interview, and chart review. A WHO grade was assigned through adjudication. The Data Safety Monitoring Board stopped the study because the difference in the grade 4 bleeding reached the prespecified threshold of 5%. At this time, 129 patients had been randomized and 119 patients were included in the analysis (58 low dose; 61 standard dose). Three patients in the low-dose arm (5.2%) had grade 4 bleeds compared with none in the standard-dose arm. WHO bleeding grade 2 or higher was 49.2% (30/61) in the standard-dose arm and 51.7% (30/58) in the low-dose group (relative risk [RR], 1.052; 95% confidence interval [CI], 0.737-1.502). A higher rate of grade 4 bleeding in patients receiving low-dose prophylactic platelet transfusions resulted in this RCT being stopped. Whether this finding was due to chance or represents a real difference requires further investigation. These clinical studies are registered on http://www.clinicaltrials.gov as NCT00420914.

Consensus and controversies in platelet transfusion: trigger for indication, and platelet dose

Platelet transfusion is about to commemorate its 50th year since its introduction in therapeutics. It is then surprising to see, that in spite of reaching this respectful age, we have not been able to definitely establish all the aspects related to its clinical use. Some of these facets are platelet transfusion threshold and the platelet dose to administer. Historically, two different transfusion triggers have been used for prophylactic and therapeutic platelet transfusions. For prophylactic platelet transfusion an increasing body of evidences suggests that a transfusion trigger of 10 x 10(9) per liter is appropriate for most clinical settings. In contrast, evidence for supporting a certain therapeutic transfusion trigger is lacking. Nevertheless, there is consensus that the platelet count should not be allowed to fall below 50 x 10(9) per liter in patients with acute bleeding. Another important aspect still pending of clear definition is the issue of the platelet dose to be transfused. It has been addressed by some small studies but a definite answer to this important clinical issue is, at least so far, still pending. The results of two ongoing trials, one sponsored by NIH through the Clinical Trials Network in Transfusion Medicine and Hemostasis and the other promoted by the BEST Collaborative Group are expected to help us to clearly defining the more effective and efficient way to transfuse platelet concentrates.