Overview of Platelet Transfusion

Reduction of Platelet Outdating and Shortage by Forecasting Demand With Statistical Learning and Deep Neural Networks: Modeling Study

BACKGROUND

Platelets are a valuable and perishable blood product. Managing platelet inventory is a demanding task because of short shelf lives and high variation in daily platelet use patterns. Predicting platelet demand is a promising step toward avoiding obsolescence and shortages and ensuring optimal care.

OBJECTIVE

The aim of this study is to forecast platelet demand for a given hospital using both a statistical model and a deep neural network. In addition, we aim to calculate the possible reduction in waste and shortage of platelets using said predictions in a retrospective simulation of the platelet inventory.

METHODS

Predictions of daily platelet demand were made by a least absolute shrinkage and selection operator (LASSO) model and a recurrent neural network (RNN) with long short-term memory (LSTM). Both models used the same set of 81 clinical features. Predictions were passed to a simulation of the blood inventory to calculate the possible reduction in waste and shortage as compared with historical data.

RESULTS

From January 1, 2008, to December 31, 2018, the waste and shortage rates for platelets were 10.1% and 6.5%, respectively. In simulations of platelet inventory, waste could be lowered to 4.9% with the LASSO and 5% with the RNN, whereas shortages were 2.1% and 1.7% with the LASSO and RNN, respectively. Daily predictions of platelet demand for the next 2 days had mean absolute percent errors of 25.5% (95% CI 24.6%-26.6%) with the LASSO and 26.3% (95% CI 25.3%-27.4%) with the LSTM (P=.01). Predictions for the next 4 days had mean absolute percent errors of 18.1% (95% CI 17.6%-18.6%) with the LASSO and 19.2% (95% CI 18.6%-19.8%) with the LSTM (P<.001).

CONCLUSIONS

Both models allow for predictions of platelet demand with similar and sufficient accuracy to significantly reduce waste and shortage in a retrospective simulation study. The possible improvements in platelet inventory management are roughly equivalent to US $250,000 per year.

Assessment and Management of Immune Thrombocytopenia (ITP) in the Emergency Department: Current Perspectives

Immune thrombocytopenia (ITP) is characterized by a platelet count less than 100 × 10^9/L without anemia or leukopenia. Patients with ITP may be asymptomatic, or they may have mild bleeding like petechiae, purpura, or epistaxis. In rare cases, they may present to the emergency department (ED) with life-threatening bleeding as a result of their thrombocytopenia. The emergency physician should thus be prepared to diagnose ITP and treat the bleeding that can result from it. The diagnosis of ITP requires excluding secondary causes of thrombocytopenia, and in the ED, the bare minimum workup for ITP includes a complete blood count and a peripheral blood smear. The peripheral blood smear should show a small number of large platelets with normal morphology, and there should not be an increased number of schistocytes. Many patients with ITP require no emergent treatment. However, if a patient with suspected ITP presents to the ED with critical hemorrhage, the emergency physician should initiate treatment with a platelet transfusion, corticosteroids, and intravenous immune globulin (IVIG) as soon as possible. For less severe bleeding, platelet transfusions are not recommended, and the treatment consists of corticosteroids by themselves or in conjunction with IVIG.

Platelet Transfusion: An Update on Indications and Guidelines

Platelets are commonly transfused either therapeutically or prophylactically to maintain hemostasis. Most platelet transfusions are used to manage patients with hematologic malignancies. Although platelet transfusion guidelines have been published, platelet transfusion practices are still heterogeneous. Platelet transfusion guidelines partly lack recommendations or differ in the platelet threshold recommendations in some clinical situations. This article reviews platelet transfusions focusing on transfusion guidelines and platelet thresholds in different clinical settings.

Platelet transfusion for patients with platelet dysfunction: effectiveness, mechanisms, and unanswered questions

PURPOSE OF REVIEW

In this review, we discuss current clinical guidelines and potential underlying mechanisms regarding platelet transfusion therapy in patients at risk of bleeding, comparing management of patients with thrombocytopenia versus those with qualitative platelet disorders.

RECENT FINDINGS

Platelet transfusion therapy is highly effective in managing bleeding in patients with hypoproliferative thrombocytopenia. Clinical trials have demonstrated that platelet transfusion can be used at a lower trigger threshold and reduced platelet doses, and may be used therapeutically rather than prophylactically in some situations, although additional data are needed. In patients with inherited platelet disorders such as Glanzmann's Thrombasthenia or those with RASGRP2 mutations, platelet transfusion may be ineffective because of competition between transfused and endogenous platelets at the site of vascular injury. Successful management of these patients may require transfusion of additional platelet units, or mechanism-driven combination therapy with other pro-hemostatic agents. In patients on antiplatelet therapy, timing of transfusion and inhibitor mechanism-of-action are key in determining therapeutic success.

SUMMARY

Expanding our understanding of the mechanisms by which transfused platelets exert their pro-hemostatic function in various bleeding disorders will improve the appropriate use of platelet transfusion.

Platelet transfusion for cancer secondary thrombocytopenia: Platelet and cancer cell interaction

Chemoradiotherapy and autoimmune disorder often lead to secondary thrombocytopenia in cancer patients, and thus, platelet transfusion is needed to stop or prevent bleeding. However, the effect of platelet transfusion remains controversial for the lack of agreement on transfusion strategies. Before being transfused, platelets are stored in blood banks, and their activation is usually stimulated. Increasing evidence shows activated platelets may promote metastasis and the proliferation of cancer cells, while cancer cells also induce platelet activation. Such a vicious cycle of interaction between activated platelets and cancer cells is harmful for the prognosis of cancer patients, which results in an increased tumor recurrence rate and decreased five-year survival rate. Therefore, it is important to explore platelet transfusion strategies, summarize mechanisms of interaction between platelets and tumor cells, and carefully evaluate the pros and cons of platelet transfusion for better treatment and prognosis for patients with cancer with secondary thrombocytopenia.

Towards Reduction or Substitution of Cytotoxic DMSO in Biobanking of Functional Bioengineered Megakaryocytes

Donor platelet transfusion is currently the only efficient treatment of life-threatening thrombocytopenia, but it is highly challenged by immunological, quality, and contamination issues, as well as short shelf life of the donor material. Ex vivo produced megakaryocytes and platelets represent a promising alternative strategy to the conventional platelet transfusion. However, practical implementation of such strategy demands availability of reliable biobanking techniques, which would permit eliminating continuous cell culture maintenance, ensure time for quality testing, enable stock management and logistics, as well as availability in a ready-to-use manner. At the same time, protocols applying DMSO-based cryopreservation media were associated with increased risks of adverse long-term side effects after patient use. Here, we show the possibility to develop cryopreservation techniques for iPSC-derived megakaryocytes under defined xeno-free conditions with significant reduction or complete elimination of DMSO. Comprehensive phenotypic and functional in vitro characterization of megakaryocytes has been performed before and after cryopreservation. Megakaryocytes cryopreserved DMSO-free, or using low DMSO concentrations, showed the capability to produce platelets in vivo after transfusion in a mouse model. These findings propose biobanking approaches essential for development of megakaryocyte-based replacement and regenerative therapies.

Human platelet lysate to substitute fetal bovine serum in hMSC expansion for translational applications: a systematic review

BACKGROUND

Foetal bovine serum (FBS), is the most commonly used culture medium additive for in vitro cultures, despite its undefined composition, its potential immunogenicity and possible prion/zoonotic transmission. For these reasons, significant efforts have been targeted at finding a substitute, such as serum free-media or human platelet-lysates (hPL). Our aim is to critically appraise the state-of-art for hPL in the published literature, comparing its impact with FBS.

MATERIALS AND METHODS

In June 2019 a systematic search of the entire Web of Science, Medline and PubMed database was performed with the following search terms: (mesenchymal stem cells) AND (fetal bovine serum OR fetal bovine calf) AND (human platelet lysate). Excluded from this search were review articles that were published before 2005, manuscripts in which mesenchymal stem cells (MSCs) were not from human sources, and when the FBS controls were missing.

RESULTS

Based on our search algorithm, 56 papers were selected. A review of these papers indicated that hMSCs cultured with hPL showed a spindle-shaped elongated morphology, had higher proliferation indexes, similar cluster of differentiation (CD) markers and no significant variation in differentiation lineage (osteocyte, adipocyte, and chondrocyte) compared to those cultured with FBS. Main sources of primary hMSCs were either fat tissue or bone marrow; in a few studies cells isolated from alternative sources showed no relevant difference in their response.

CONCLUSION

Despite the difference in medium choice and a lack of standardization of hPL manufacturing, the majority of publications support that hPL was at least as effective as FBS in promoting adhesion, survival and proliferation of hMSCs. We conclude that hPL should be considered a viable alternative to FBS in hMSCs culture-especially with a view for their clinical use.

Platelet Transfusion: And Update on Challenges and Outcomes

Platelet transfusion is a common practice in onco-hematologic patients for preventing or treating hemorrhages. Platelet concentrates can be transfused with therapeutic or prophylactic purposes. With the aim to help clinicians to take the decisions on platelet transfusion, some guidelines have been developed based on the current scientific evidence. However, there are some controversial issues and available scientific evidence is not enough to solve them. There is little information about what is the best platelet product to be transfused: random platelets or single donor apheresis platelets, and plasma-suspended or additive solution suspended platelets. Platelets are often transfused without respecting the ABO compatibility, but influence of this practice on platelet transfusion outcome is not well established. In the prophylactic platelet transfusion set there are some questions unsolved as the platelet threshold to transfuse prior to specific procedures or surgery, and even if platelet transfusion is necessary for some specific procedures as autologous hematopoietic stem cell transplantation. A challenging complication raised from multiple platelet transfusions is the platelet transfusion refractoriness. The study and management of this complication is often disappointing. In summary, although it is a widespread practice, platelet transfusion has still many controversial and unknown issues. The objective of this article is to review the current evidence on platelet transfusion practices, focusing on the controversial issues and challenges.

Allele and haplotype frequencies of human platelet and leukocyte antigens in platelet donors

OBJECTIVE

To described the allele and haplotype frequencies of human leukocyte antigen genes at the -A, -B loci and human platelet antigen genes for human platelet antigen systems 1 to 9, 11 and 15 in blood.

METHODS

We included 867 healthy unrelated volunteer donors who donated platelets between January 2011 and December 2014. Microarray genotyping was performed using a BeadChip microarray. Medium resolution typing of the human leukocyte antigen at loci A and B was carried out using sequence-specific oligonucleotide probe hybridization. We used multivariate analysis and our human leukocyte antigen population was compared to data from the United States national bone marrow donor program. Human platelet antigen results were compared to a literature review and data from around the world.

RESULTS

Our human leukocyte antigen haplotype results were more similar to those of hispanics, followed by caucasians. Likewise, our human platelet antigen sample is more similar to those of Argentina, Rio Grande do Sul and Italy.

CONCLUSION

This was the first article that discusses human platelet antigen and human leukocyte antigen data together. Rare genotypes or antibody associations can make patient management difficult. A blood bank with genotyped donors allows for optimal transfusion and can contribute to better results. Our information can serve as basis for a database of platelet antigen polymorphisms.

Ultraviolet-Based Pathogen Inactivation Systems: Untangling the Molecular Targets Activated in Platelets

Transfusions of platelets are an important cornerstone of medicine; however, recipients may be subject to risk of adverse events associated with the potential transmission of pathogens, especially bacteria. Pathogen inactivation (PI) technologies based on ultraviolet illumination have been developed in the last decades to mitigate this risk. This review discusses studies of platelet concentrates treated with the current generation of PI technologies to assess their impact on quality, PI capacity, safety, and clinical efficacy. Improved safety seems to come with the cost of reduced platelet functionality, and hence transfusion efficacy. In order to understand these negative impacts in more detail, several molecular analyses have identified signaling pathways linked to platelet function that are altered by PI. Because some of these biochemical alterations are similar to those seen arising in the context of routine platelet storage lesion development occurring during blood bank storage, we lack a complete picture of the contribution of PI treatment to impaired platelet functionality. A model generated using data from currently available publications places the signaling protein kinase p38 as a central player regulating a variety of mechanisms triggered in platelets by PI systems.

Preprocedural platelet transfusion for patients with thrombocytopenia undergoing interventional radiology procedures is not associated with reduced bleeding complications

BACKGROUND

Platelet (PLT) transfusion before interventional radiology procedures is commonly performed in patients with thrombocytopenia. However, it is unclear if PLT transfusion is associated with reduced bleeding complications.

STUDY DESIGN AND METHODS

This is a retrospective cohort study of adults undergoing interventional radiology procedures between January 1, 2009, and December 31, 2013. Baseline characteristics, coagulation variables, transfusion requirements, and procedural details were evaluated. Propensity-matched analyses were used to assess relationships between PLT transfusions and the outcomes of interest, including a primary outcome of periprocedural red blood cell (RBC) transfusion during the procedure or within the first 24 hours after procedure.

RESULTS

A total of 18,204 participants met inclusion criteria, and 2060 (11.3%) had a PLT count of not more than 100 × 10⁹ /L before their procedure. Of these, 203 patients (9.9) received preprocedural PLTs. There was no significant difference in RBC requirements between those receiving or not receiving preprocedural PLTs in propensity-matched analysis (odds ratio [OR], 1.45; 95% confidence interval [CI], 0.95-2.21; p = 0.085). PLT transfusion was associated with increased rates of intensive care unit admission (OR [95% CI], 1.57 [1.07-2.32]; p = 0.022).

CONCLUSION

In patients with thrombocytopenia undergoing interventional radiology procedures, preprocedural PLT transfusion was not associated with reduced periprocedural RBC requirements. These findings suggest that prophylactic PLT transfusions are not warranted in nonbleeding patients with preprocedural PLT counts exceeding 50 × 10⁹ /L. Future clinical trials are needed to further define relationships between prophylactic PLT administration and bleeding complications, especially at more severe levels of thrombocytopenia or in the presence of PLT dysfunction.

Platelet count evolution as a predictor of outcome after splenectomy for immune thrombocytopenic purpura

Splenectomy is the definitive second-line therapy for refractory immune thrombocytopenic purpura (ITP), and has a reported response rate of 50-80%. Medical attention should be reconsidered when there is no evidence of accessory spleen in refractory ITP patients after splenectomy. The purpose of this study was to determine whether platelet count evolution differs between patients with a successful or unsuccessful result after splenectomy for ITP. Archived records of 104 consecutive patients that underwent splenectomy for ITP were reviewed. Patients were divided into two groups (failures and successes) using a final follow-up platelet count of 100,000/μL as a cut-off. Platelet count evolutions in these two groups were compared using the Student's t test. Successes and failures were found to have significantly different platelet counts from two days postoperatively (P = 0.016). The area under the receiver operating characteristic curve was 0.630 (95% confidence interval, 0.518-0.741, P = 0.030), and when a cut-off value of 100,000/μL was used, sensitivity and specificity were 68.2 and 51.2%, respectively. To obtain positive and negative predictive values exceeding 50%, additional platelet counts were required at one week and one month after splenectomy. We propose a protocol for ITP follow-up after splenectomy.

Blood Products

Perioperative hemorrhage, anemia, thrombocytopenia, and coagulopathy are common in the surgical intensive care unit. As a result, blood product transfusion occurs frequently. While red blood cell, plasma, and platelet transfusions have a lifesaving role in the resuscitation of patients with trauma and hemorrhagic shock, their application in other settings is under scrutiny. Current data would suggest a conservative approach be taken, thus avoiding unnecessary transfusion and associated potential adverse events. New and developmental products such as prothrombin complex concentrates offer appealing alternatives to traditional transfusion practice—potentially with fewer risks—however, further investigation into their safety and efficacy is required before practice change can take place.

Human platelet lysate: Replacing fetal bovine serum as a gold standard for human cell propagation?

The essential physiological role of platelets in wound healing and tissue repair builds the rationale for the use of human platelet derivatives in regenerative medicine. Abundant growth factors and cytokines stored in platelet granules can be naturally released by thrombin activation and clotting or artificially by freeze/thaw-mediated platelet lysis, sonication or chemical treatment. Human platelet lysate prepared by the various release strategies has been established as a suitable alternative to fetal bovine serum as culture medium supplement, enabling efficient propagation of human cells under animal serum-free conditions for a multiplicity of applications in advanced somatic cell therapy and tissue engineering. The rapidly increasing number of studies using platelet derived products for inducing human cell proliferation and differentiation has also uncovered a considerable variability of human platelet lysate preparations which limits comparability of results. The main variations discussed herein encompass aspects of donor selection, preparation of the starting material, the possibility for pooling in plasma or additive solution, the implementation of pathogen inactivation and consideration of ABO blood groups, all of which can influence applicability. This review outlines the current knowledge about human platelet lysate as a powerful additive for human cell propagation and highlights its role as a prevailing supplement for human cell culture capable to replace animal serum in a growing spectrum of applications.

Platelet transfusion for patients with cancer

BACKGROUND

Platelet transfusion is a critical and often necessary aspect of managing cancer. Low platelet counts frequently lead to bleeding complications; however, the drugs used to combat malignancy commonly lead to decreased production and destruction of the very cell whose function is essential to stop bleeding. The transfusion of allogeneic platelet products helps to promote hemostasis, but alloimmunization may make it difficult to manage other complications associated with cancer.

METHODS

The literature relating to platelet transfusion in patients with cancer was reviewed.

RESULTS

Platelet storage, dosing, transfusion indications, and transfusion response are essential topics for health care professionals to understand because many patients with cancer will require platelet transfusions during the course of treatment. The workup and differentiation of non-immune-mediated compared with immune-mediated platelet refractoriness are vital because platelet management is different between types of refractoriness.

CONCLUSIONS

A combination of appropriate utilization of platelet inventory and laboratory testing coupled with communication between those caring for patients with cancer and those providing blood products is essential for effective patient care.

The Inflammatory Role of Platelets via Their TLRs and Siglec Receptors

Platelets are non-nucleated cells that play central roles in the processes of hemostasis, innate immunity, and inflammation; however, several reports show that these distinct functions are more closely linked than initially thought. Platelets express numerous receptors and contain hundreds of secretory products. These receptors and secretory products are instrumental to the platelet functional responses. The capacity of platelets to secrete copious amounts of cytokines, chemokines, and related molecules appears intimately related to the role of the platelet in inflammation. Platelets exhibit non-self-infectious danger detection molecules on their surfaces, including those belonging to the “toll-like receptor” family, as well as pathogen sensors of other natures (Ig- or complement receptors, etc.). These receptors permit platelets to both bind infectious agents and deliver differential signals leading to the secretion of cytokines/chemokines, under the control of specific intracellular regulatory pathways. In contrast, dysfunctional receptors or dysregulation of the intracellular pathway may increase the susceptibility to pathological inflammation. Physiological vs. pathological inflammation is tightly controlled by the sensors of danger expressed in resting, as well as in activated, platelets. These sensors, referred to as pathogen recognition receptors, primarily sense danger signals termed pathogen associated molecular patterns. As platelets are found in inflamed tissues and are involved in auto-immune disorders, it is possible that they can also be stimulated by internal pathogens. In such cases, platelets can also sense danger signals using damage associated molecular patterns (DAMPs). Some of the most significant DAMP family members are the alarmins, to which the Siglec family of molecules belongs. This review examines the role of platelets in anti-infection immunity via their TLRs and Siglec receptors.

Utilization of cross-matched or HLA-matched platelets for patients refractory to platelet transfusion

BACKGROUND

Use of cross matching or HLA matching for donor selection is the basis of managing patients refractory to platelet (PLT) transfusion. Because of changes in patient care, we evaluated the effect of cross matching and HLA matching in patients refractory to PLT transfusion.

STUDY DESIGN AND METHODS

We identified all patients who received either HLA-matched or cross-matched PLTs during a 3-year period at our medical center. Patient records were reviewed and laboratory data were collected. One- to 4-hour corrected count increments (CCIs) were calculated for transfusions given up to 72 hours before receiving these specialized units and the HLA-matched or cross-matched units themselves.

RESULTS

Thirty-two patients were identified who received a total of 354 PLT transfusions. Of these, 161 were from unselected apheresis, 152 were cross matched, and 41 were HLA selected. The median CCI for random-donor transfusions was 0 (range, 0 × 10(9)-10.5 × 10(9)/L), for cross-matched PLT transfusions 1.7 × 10(9)/L (0 × 10(9)-5.1 × 10(9)/L), and for HLA-matched transfusions 1.2 × 10(9)/L (0 × 10(9)-13.9 × 10(9)/L). Only 25 and 30% of cross-match-compatible or HLA-selected units, respectively, gave 1- to 4-hour CCIs of more than 5.0 × 10(9)/L compared to 12% of the transfusions from random donors. There were no significant differences in the 1- to 4-hour CCIs when comparing random units with HLA-selected or cross-match-compatible units. There was also no significant difference when comparing the HLA-matched and cross-match-compatible PLT units with each other.

CONCLUSIONS

The use of cross-match-compatible or HLA-matched units did not provide better increments in PLT count when compared to random nonselected units. Clinical factors may overpower immunologic matching.

A Review of and Recommendations for the Management of Patients With Life-Threatening Dabigatran-Associated Hemorrhage

Dabigatran is an oral direct thrombin inhibitor that is approved for the prevention of stroke and systemic embolism in nonvalvular atrial fibrillation. Dabigatran has several advantages over warfarin including predictable pharmacokinetics and pharmacodynamics which eliminates the need for routine laboratory monitoring, superiority over warfarin in preventing stroke, or systemic embolism without having an increased risk of bleeding. However, as with any anticoagulant, there remains a real chance of bleeding, including major or life-threatening hemorrhage. Many physicians feel comfortable managing bleeding complications on older anticoagulants like warfarin and heparin, due to extensive experience with the medications along with antidotes to reverse their effects as well as established protocols for treating anticoagulant-associated hemorrhage. However, most physicians have limited clinical experience with dabigatran, there is no specific antidote for dabigatran reversal and there is a paucity of protocols, guidelines, and recommendations for how to manage dabigatran-associated hemorrhage. In this review, we present a case series of patients admitted to our institution for management of bleeding while receiving dabigatran. We retrospectively reviewed these cases to evaluate the efficacy and rationale of the various anticoagulation reversal strategies employed in the context of the existing evidence found in the literature. Specific focus is placed on the therapies utilized and the coagulation studies used to manage these patients.

Animating platelet production adds physiological context

Animating complex biological processes contextualizes them within their underlying physiology, identifies gaps in our mechanistic understanding, affirms the importance of continued research, and provides a bridge between academic scientists and the general public. Here, two videos illustrate the clinical value of and translate state-of-the-art research in platelet production.

Case management and supportive treatment for patients with Crimean-Congo hemorrhagic fever

Crimean-Congo hemorrhagic fever (CCHF) is a tick-borne infection which has been increasing in Turkey and European countries since the year 2000. The disease is particularly endemic in the Middle East and in some African countries. It is also seen in European countries as a travel infection. Patients with confirmed diagnosis are usually hospitalized for monitoring, while patients with good overall condition may be monitored on an outpatient basis. Hospitals that manage CCHF should have easy access to a blood bank, and tertiary care hospitals must have a well-equipped intensive care unit. Strict blood and body fluid control precautions should be started on admission to limit CCHF exposure. The follow-up period for each patient is determined based on individual clinical status and laboratory values. Since there is no specific antiviral treatment for CCHF, supportive treatment is essential. This review highlights some of the major features of case monitoring and supportive treatment in CCHF.

High concentration plasma-reduced plateletapheresis concentrates

Single-donor hyperconcentrated plateletapheresis (dry-platelets) collection has been introduced in the 90's as a part of the newly developed multi-component collection strategy. This approach allowed to safely collect multiple components from a single apheresis donation, i.e. RBC, FFP and/or plateletpheresis units. Dry-platelets are usually resuspended in additive solution to maintain an adequate pH during the storage period until use. Some concern existed about possible higher degrees of platelet activation in dry-platelets units when compared to standard concentration (1.0-1.6 × 10(6)/μL platelets) units and its possible correlation with lower in vivo efficiency and/or survival of the former units. Several authors investigated this specific issue, and dry-platelets units proved to be equally effective than standard concentration plateletpheresis units in recipients. The use of dry-platelets units may reduce (i) the risk of passive infusion of naturally occurring ABO-related hemolytic antibodies when donor O platelets are given to group A, B, or AB recipient, (ii) the risk of TRALI when multiparous donors undergo plateletpheresis. Furthermore, dry-platelet collection may allow for an increased amount of FFP sent to industry. Finally, hyperconcentrated platelet units may be used for "niche" indications, such as intrauterine platelet transfusion or, in case of autologous dry-platelet collection, for further freezing for long term storage in selected patients within onco-hematological settings.