Current concepts in platelet transfusion

Delayed-onset eptifibatide-induced thrombocytopenia

PURPOSE

We present a unique case of delayed-onset, profound eptifibatide-induced thrombocytopenia that occurred 5 days after initiation of the drug.

SUMMARY

Eptifibatide is a platelet glycoprotein IIb/IIIa receptor inhibitor with indications for use in patients with acute coronary syndromes. Eptifibatide-induced thrombocytopenia is uncommon but well studied and typically occurs within 24 hours of initiation of the drug. In the case described here, a 62-year-old male with a past history of coronary artery disease (including percutaneous coronary intervention within the past 12 months) was started on eptifibatide at a dosage of 2 µg/kg per minute for management of significant thrombus burden prior to a planned cardiac revascularization procedure; heparin for anticoagulation was also initiated. About 5 days after initiation of eptifibatide, the patient developed severe thrombocytopenia, with the platelet count dropping precipitously from 249 × 103/µL on admission to less than 1 × 103/µL. After eptifibatide and heparin therapy were discontinued and the patient was switched to argatroban, the platelet count recovered to 38 × 103/µL over the next 2 days. An eptifibatide platelet antibody assay was positive for IgG-mediated reactions consistent with eptifibatide-induced thrombocytopenia. Scoring of this case with the Naranjo scale yielded a score of 4, suggesting a possible adverse reaction to eptifibatide.

CONCLUSION

This is the first published case report of profound eptifibatide-induced thrombocytopenia occurring more than 24 hours after eptifibatide initiation and serves to bring awareness that a delayed reaction can occur.

Emergency cesarean section in glanzmann thrombasthenia: Anaesthetic management without recombinant factor VIIa

Glanzmann thrombasthenia (GT) is a congenital disorder inherited autosomal recessively, caused by deficiency of platelet membrane glycoprotein IIb-IIIa complex leading to defective platelet aggregation, and manifesting as mucocutaneous bleeding. Parturients with GT requiring emergency cesarean section are at high risk for perioperative bleeding complications. The anesthetist should be prepared with the necessary measures to control bleeding. This paper presents the successful management of a 23-year-old primigravida with GT undergoing cesarean section in a resource-limited setup where thromboelastography and recombinant factor VIIa (rFVIIa) are not available.

Perinatal Transmission of Dengue Infection among Dengue Hemorrhagic Fever Outbreaks in Southern Vietnam: The First Case Managed at Tu Du Hospital and Review of Literature

Dengue hemorrhagic fever is a high-risk pathology in pregnancy, leading to an increased mortality rate for both the mother and baby. Perinatal transmission of dengue infection may occur during the labor stage of the febrile phase, despite its extreme rarity. In the present case, a young female patient with pregnancy at 39 weeks 3 days of gestational age was hospitalized because of dengue hemorrhagic fever. Upon monitoring, her platelet count gradually decreased to a very low of 13,000 mm3 on the third day of fever. However, her platelet count increased soon afterwards. On the eighth day of admission, she was delivered by emergency cesarean section due to acute fetal distress. The female neonate was promptly assessed by the pediatric team upon cesarean surgery. The neonate was diagnosed with vertical transmission of dengue infection based on positive dengue virus nonstructural protein 1 antigen, and low platelet count was found on the first day postpartum. When there is a high suspicion of perinatal transmission, closely monitoring the newborn helps to avoid the adverse outcomes and mortality for the infant. Herein, we thoroughly report an unusual case of maternal-fetal transmission of dengue during pregnancy at our maternity hospital.

Advancement and Applications of Platelet-inspired Nanoparticles: A Paradigm for Cancer Targeting

Platelet-inspired nanoparticles have ignited the possibility of new opportunities for producing similar biological particulates, such as structural cellular and vesicular components, as well as various viral forms, to improve biocompatible features that could improve the nature of biocompatible elements and enhance therapeutic efficacy. The simplicity and more effortless adaptability of such biomimetic techniques uplift the delivery of the carriers laden with cellular structures, which has created varied opportunities and scope of merits like; prolongation in circulation and alleviating immunogenicity improvement of the site-specific active targeting. Platelet-inspired nanoparticles or medicines are the most recent nanotechnology-based drug targeting systems used mainly to treat blood-related disorders, tumors, and cancer. The present review encompasses the current approach of platelet-inspired nanoparticles or medicines that have boosted the scientific community from versatile fields to advance biomedical sciences. Surprisingly, this knowledge has streamlined to development of newer diagnostic methods, imaging techniques, and novel nanocarriers, which might further help in the treatment protocol of the various diseased conditions. The review primarily focuses on the novel advancements and recent patents in nanoscience and nanomedicine that could be streamlined in the future for the management of progressive cancers and tumor targeting. Rigorous technological advancements like biomimetic stem cells, pH-sensitive drug delivery of nanoparticles, DNA origami devices, virosomes, nano cells like exosomes mimicking nanovesicles, DNA nanorobots, microbots, etc., can be implemented effectively for target-specific drug delivery.

Antiplatelet Therapy for Atherothrombotic Disease in 2022—From Population to Patient-Centered Approaches

Antiplatelet agents, with aspirin and P2Y₁₂ receptor antagonists as major key molecules, are currently the cornerstone of pharmacological treatment of atherothrombotic events including a variety of cardio- and cerebro-vascular as well as peripheral artery diseases. Over the last decades, significant changes have been made to antiplatelet therapeutic and prophylactic strategies. The shift from a population-based approach to patient-centered precision medicine requires greater awareness of individual risks and benefits associated with the different antiplatelet strategies, so that the right patient gets the right therapy at the right time. In this review, we present the currently available antiplatelet agents, outline different management strategies, particularly in case of bleeding or in perioperative setting, and develop the concept of high on-treatment platelet reactivity and the steps toward person-centered precision medicine aiming to optimize patient care.

Indian College of Radiology and Imaging Evidence-Based Guidelines for Interventions in Portal Hypertension and Its Complications

Portal hypertension is a complication of chronic liver disease. Various radiological interventions are being done to aid in the diagnosis of portal hypertension; further, an interventional radiologist can offer various treatments for the complications of portal hypertension. Diagnosis of portal hypertension in its early stage may require hepatic venous pressure gradient measurement. Measurement of gradient also guides in diagnosing the type of portal hypertension, measuring response to treatment and prognostication. This article attempts to provide evidence-based guidelines on the management of portal hypertension and treatment of its complications.

Indian College of Radiology and Imaging Evidence-Based Guidelines for Percutaneous Image-Guided Biliary Procedures

Percutaneous biliary interventions are among the commonly performed nonvascular radiological interventions. Most common of these interventions is the percutaneous transhepatic biliary drainage for malignant biliary obstruction. Other biliary procedures performed include percutaneous cholecystostomy, biliary stenting, drainage for bile leaks, and various procedures like balloon dilatation, stenting, and large-bore catheter drainage for bilioenteric or post-transplant anastomotic strictures. Although these procedures are being performed for ages, no standard guidelines have been formulated. This article attempts at preparing guidelines for performing various percutaneous image-guided biliary procedures along with discussion on the published evidence in this field.

Activity-based cost of platelet transfusions in medical and surgical inpatients at a US hospital

BACKGROUND AND OBJECTIVES

Previous studies by the Cost of Blood Consensus Conference (COBCON) have used a comprehensive, standardized and generalizable activity-based costing (ABC) model to estimate the cost of red blood cell transfusions and plasma transfusion. The objective of this study was to determine the total cost of platelet transfusions in a real-world US hospital inpatient setting.

MATERIALS AND METHODS

This database analysis study retrospectively collected costs for all activities related to platelet transfusion in a single-acute care US teaching hospital in 2017. Costs were collected in a stepwise manner using a custom ABC model which mapped the technical, administrative and clinical processes involved in the transfusion of platelets.

RESULTS

For the 15 024 inpatients included in the analysis, 6335 (42·2%) were given a blood type and screen, and 941 (6·3%) received a transfusion of one or more blood products. A total of 333 platelet units were transfused in 131 patients (mean 2·54 units per patient): 211 (63·4%) units in medical inpatients and 122 (36·6%) in surgical inpatients. The total cost was $1359·99 per platelet unit, corresponding to $3457·06 per inpatient. Acquisition costs made up the largest proportion of the total cost (45·1%) followed by direct and indirect overheads (38·7%) and hospital processes costs (16·3%).

CONCLUSION

This is the first study to use an ABC costing model to determine the full cost of platelet transfusions within a US inpatient setting. This provides a useful reference point for comparisons with other transfusion products, and considerations for cost reduction.

Quantitation of phosphatidylserine-exposing platelets and platelet-derived microparticles in platelet products: A new strategy to improve efficacy of platelet transfusion

Platelet transfusion is an effective therapy to prevent or treat bleeding. Considering the different clinical purposes of transfusion, it is necessary to assess the quality of platelet products prepared in transfusion laboratories. So far, there is no solution to the problem of how best to do this. Here, we summarize the quantitation of phosphatidylserine (PS)-exposing platelets and platelet-derived microparticles (PMPs) in platelet products using previously reported data. Because PS promotes the assembly and enhances the activity of coagulation factors, classifying platelet products according to their concentrations of PS-exposing platelets and PMPs will improve the therapeutic treatment of transfusion recipients.

Affordable, Reliable Dual-Platform Approach to Quantitating Phosphatidylserine-Exposing Platelets in Platelet Components

OBJECTIVE

To compare the number of phosphatidylserine (PS)-exposing platelets obtained using the dual-platform approach and bead-based flow cytometry.

METHODS

Platelets were enumerated using the ADVIA 2010i instrument (Siemens AG). The numbers and percentages of PS-exposing platelets in 175 platelet products were determined using a FACSCalibur flow cytometer (Becton, Dickinson and Company) and counting beads.

RESULTS

Our results showed good correlation (r2 = 0.96; P <.001) between the PS-exposing platelets obtained using counting beads and the dual-platform approach. The results of Bland-Altman analysis showed a bias of +46,449 cells per µL and a limit of agreement (LOA) from -197,863 to 290,762 cells per µL. Also, 8 measurements (5.0%) revealed a number of PS-exposing platelets outside the LOA ranges. Further, 21 measurements (12.0%) revealed greater than 2-fold changes in the number of PS-exposing platelets.

CONCLUSIONS

The results suggest that the dual-platform approach is affordable and reliable for quantitating PS-exposing platelets as part of monitoring the quality of platelet products.

Quantitation of Cell-Derived Microparticles in Blood Products and Its Potential Applications in Transfusion Laboratories

Cell-derived microparticles (MPs) are small fragments released from various cells when they are activated or undergo apoptosis. In the field of transfusion medicine, a number of studies have documented increased levels of MPs in blood products, which have been associated with multiple factors, including donor variability, blood component processing, and storage. In addition, transfusions that contain high levels of MPs are linked to posttransfusion complications. Considering the clinical importance of MP levels, transfusion laboratories should routinely screen blood products for them. However, this practice is not yet applied routinely, perhaps in part because of a lack of understanding of how to apply MP data to transfusion medicine. We describe the methods used to quantitate MPs in blood components and discuss the application of these quantitative data in routine transfusion laboratories in order to manage quality, improve the outcomes of transfusions, and minimize their complications.

Lusutrombopag for the Treatment of Thrombocytopenia in Patients With Chronic Liver Disease Undergoing Invasive Procedures (L-PLUS 2)

Thrombocytopenia may be associated with increased bleeding risk impacting timing and outcome of invasive procedures in patients with chronic liver disease (CLD). Lusutrombopag, a small-molecule, thrombopoietin (TPO) receptor agonist, was evaluated as a treatment to raise platelet counts (PCs) in patients with thrombocytopenia and CLD undergoing invasive procedures. L-PLUS 2 was a global, phase 3, randomized, double-blind, placebo-controlled study. Adults with CLD and baseline PCs < 50 × 10⁹ /L were randomized to receive once-daily lusutrombopag 3 mg or placebo ≤ 7 days before an invasive procedure scheduled 2-7 days after the last dose. The primary endpoint was avoidance of preprocedure platelet transfusion and avoidance of rescue therapy for bleeding. A key secondary endpoint was number of days PCs were ≥ 50 × 10⁹ /L throughout the study. Safety analysis was performed on patients who received at least one dose of study drug. This study occurred between June 15, 2015, and April 19, 2017, with a total of 215 randomized patients (lusutrombopag, 108; placebo, 107); 64.8% (70/108) of patients in the lusutrombopag group versus 29.0% (31/107) in the placebo group met the primary endpoint (P < 0.0001; difference of proportion 95% confidence interval [CI], 36.7 [24.9, 48.5]). The median duration of PCs ≥ 50 × 10⁹ /L was 19.2 days with lusutrombopag (without platelet transfusion) compared with 0.0 in the placebo group (with platelet transfusion) (P = 0.0001). Most adverse events were mild or moderate in severity, and rates were similar in the lusutrombopag and placebo groups (47.7% and 48.6%, respectively). Conclusion: Lusutrombopag was superior to placebo for reducing the need for platelet transfusions and achieved durable PC response in patients with thrombocytopenia and CLD undergoing invasive procedures, with a safety profile similar to placebo.

Assessment of Time-Dependent Platelet Activation Using Extracellular Vesicles, CD62P Exposure, and Soluble Glycoprotein V Content of Platelet Concentrates with Two Different Platelet Additive Solutions

Novel analytical measures are needed to accurately monitor the properties of platelet concentrates (PCs). Since activated platelets produce platelet-derived extracellular vesicles (EVs), analyzing EVs of PCs may provide additional information about the condition of platelets. The prospect of using EVs as an auxiliary measure of platelet activation state was investigated by examining the effect of platelet additive solutions (PASs) on EV formation and platelet activation during PC storage. The time-dependent activation of platelets in PCs with PAS-B or with the further developed PAS-E was compared by measuring the exposure of CD62P by flow cytometry and the content of soluble glycoprotein V (sGPV) of PCs by an immunoassay. Changes in the concentration and size distribution of EVs were determined using nanoparticle tracking analysis. A time-dependent increase in platelet activation in PCs was demonstrated by increased CD62P ex-posure, sGPV content, and EV concentration. Using these strongly correlating parameters, PAS-B platelets were shown to be more activated compared to PAS-E platelets. Since the EV concentration correlated well with the established platelet activation markers CD62P and sGPV, it could potentially be used as a complementary parameter for platelet activation for PCs. More detailed characterization of the resulting EVs could help to understand how the PC components contribute the functional effects of transfused PCs.

Biomaterials and Advanced Technologies for Hemostatic Management of Bleeding

Bleeding complications arising from trauma, surgery, and as congenital, disease-associated, or drug-induced blood disorders can cause significant morbidities and mortalities in civilian and military populations. Therefore, stoppage of bleeding (hemostasis) is of paramount clinical significance in prophylactic, surgical, and emergency scenarios. For externally accessible injuries, a variety of natural and synthetic biomaterials have undergone robust research, leading to hemostatic technologies including glues, bandages, tamponades, tourniquets, dressings, and procoagulant powders. In contrast, treatment of internal noncompressible hemorrhage still heavily depends on transfusion of whole blood or blood's hemostatic components (platelets, fibrinogen, and coagulation factors). Transfusion of platelets poses significant challenges of limited availability, high cost, contamination risks, short shelf-life, low portability, performance variability, and immunological side effects, while use of fibrinogen or coagulation factors provides only partial mechanisms for hemostasis. With such considerations, significant interdisciplinary research endeavors have been focused on developing materials and technologies that can be manufactured conveniently, sterilized to minimize contamination and enhance shelf-life, and administered intravenously to mimic, leverage, and amplify physiological hemostatic mechanisms. Here, a comprehensive review regarding the various topical, intracavitary, and intravenous hemostatic technologies in terms of materials, mechanisms, and state-of-art is provided, and challenges and opportunities to help advancement of the field are discussed.

Bio-inspired nanomedicine strategies for artificial blood components

Blood is a fluid connective tissue where living cells are suspended in noncellular liquid matrix. The cellular components of blood render gas exchange (RBCs), immune surveillance (WBCs) and hemostatic responses (platelets), and the noncellular components (salts, proteins, etc.) provide nutrition to various tissues in the body. Dysfunction and deficiencies in these blood components can lead to significant tissue morbidity and mortality. Consequently, transfusion of whole blood or its components is a clinical mainstay in the management of trauma, surgery, myelosuppression, and congenital blood disorders. However, donor-derived blood products suffer from issues of shortage in supply, need for type matching, high risks of pathogenic contamination, limited portability and shelf-life, and a variety of side-effects. While robust research is being directed to resolve these issues, a parallel clinical interest has developed toward bioengineering of synthetic blood substitutes that can provide blood's functions while circumventing the above problems. Nanotechnology has provided exciting approaches to achieve this, using materials engineering strategies to create synthetic and semi-synthetic RBC substitutes for enabling oxygen transport, platelet substitutes for enabling hemostasis, and WBC substitutes for enabling cell-specific immune response. Some of these approaches have further extended the application of blood cell-inspired synthetic and semi-synthetic constructs for targeted drug delivery and nanomedicine. The current study provides a comprehensive review of the various nanotechnology approaches to design synthetic blood cells, along with a critical discussion of successes and challenges of the current state-of-art in this field. WIREs Nanomed Nanobiotechnol 2017, 9:e1464. doi: 10.1002/wnan.1464 For further resources related to this article, please visit the WIREs website.

In vitro characterization of SynthoPlate™ (synthetic platelet) technology and its in vivo evaluation in severely thrombocytopenic mice

Essentials Platelet transfusion suffers from availability, portability, contamination, and short shelf-life. SynthoPlate™ (synthetic platelet technology) can resolve platelet transfusion limitations. SynthoPlate™ does not activate resting platelets or stimulate coagulation systemically. SynthoPlate™ significantly improves hemostasis in thrombocytopenic mice dose-dependently.

SUMMARY

Background Platelet transfusion applications face severe challenges, owing to the limited availability and portability, high risk of contamination and short shelf-life of platelets. Therefore, there is significant interest in synthetic platelet substitutes that can provide hemostasis while avoiding these issues. Platelets promote hemostasis by injury site-selective adhesion and aggregation, and propagation of coagulation reactions on their membranes. On the basis of these mechanisms, we have developed a synthetic platelet technology (SynthoPlate™) that integrates platelet-mimetic site-selective 'adhesion' and 'aggregation' functionalities via heteromultivalent surface decoration of lipid vesicles with von Willebrand factor-binding, collagen-binding and active platelet integrin glycoprotein (GP) IIb-IIIa-binding peptides. Objective To evaluate SynthoPlate for its effects on platelets and plasma in vitro, and for systemic safety and hemostatic efficacy in severely thrombocytopenic mice in vivo. Methods In vitro, SynthoPlate was evaluated with aggregometry, fluorescence microscopy, microfluidics, and thrombin and fibrin generation assays. In vivo, SynthoPlate was evaluated for systemic safety with prothrombin and fibrin assays on plasma, and for hemostatic effects on tail-transection bleeding time in severely thrombocytopenic (TCP) mice. Results SynthoPlate did not aggregate resting platelets or spontaneously promote coagulation in plasma, but could amplify the recruitment and aggregation of active platelets at the bleeding site, and thereby site-selectively enhance fibrin generation. SynthoPlate dose-dependently reduced bleeding time in TCP mice, to levels comparable to those in normal mice. SynthoPlate has a reasonable circulation residence time, and is cleared mostly by the liver and spleen. Conclusion The results demonstrate the promise of SynthoPlate as a synthetic platelet substitute in transfusion treatment of platelet-related bleeding complications.

Mimicking adhesive functionalities of blood platelets using ligand-decorated liposomes

Platelet transfusion is used for treating a variety of bleeding complications. Natural platelet-based transfusion products have very short storage life (3-7 days) and high risks of biological contamination and side effects. Consequently, there is significant clinical interest in synthetic platelet-mimetic constructs that can promote hemostasis, while allowing convenient large-scale production, easy portability, long storage life, and minimal biological risks. To this end, research efforts are being directed toward particles that can amplify aggregation of activated platelets or can mimic platelet's ability to undergo adhesion to various vascular matrix proteins. Here, we report on a synthetic construct design that combines the mimicry of platelet's shear-dependent adhesion to vWF and shear-independent adhesion to collagen under flow, on a single particle. For this, we have used 150-nm-diameter liposomes as model particles and have decorated their surface simultaneously with vWF-binding and collagen-binding recombinant protein fragments or synthetic peptide motifs. We demonstrate in vitro that these surface-modified liposomes are able to adhere onto vWF surfaces in a shear-dependent fashion and onto collagen surfaces in a shear-independent fashion under flow. Moreover, when the vWF-binding and the collagen-binding were integrated on a single liposomal platform, the resultant heteromultivalent liposomes showed significantly enhanced adhesion to a vWF/collagen mixed surface compared to liposomes bearing vWF-binding or collagen-binding ligands only, as long as the ligand motifs did not spatially interfere with each other. Altogether, our results establish the feasibility of efficiently mimicking platelet's dual adhesion mechanisms on synthetic particles.

Peptide-decorated liposomes promote arrest and aggregation of activated platelets under flow on vascular injury relevant protein surfaces in vitro

Platelet-mimetic synthetic hemostats are highly attractive in transfusion medicine. To this end, past research reports have described particles that either amplify platelet aggregation or mimic platelet adhesion. However, a construct design that effectively combines both functionalities has not been reported. Here we describe the design of a liposomal construct simultaneously surface-decorated with three peptides (a vWF-binding peptide (VBP), a collagen-binding peptide (CBP), and an active platelet clustering cyclic-RGD (cRGD) peptide), that can integrate platelet-mimetic dual hemostatic activities of adhesion and aggregation. We first demonstrate that surface-immobilized cRGD-liposomes are capable of aggregating activated platelets onto themselves. Subsequently, we demonstrate that hetero-multivalent liposomes bearing VBP, CBP, and cRGD, when introduced in flow with ≈ 20,000 activated platelets per microliter, are capable of adhering to vWF/collagen surfaces and promoting the recruitment/aggregation of platelets onto themselves. We envision that optimizing this construct can lead to a highly refined synthetic hemostat design for potential application in transfusion medicine.

HLA Antigens Shed from the Surface of Synthetic or Naturally Occurred Platelet-Derived Microparticles During Storage of Platelet Concentrate

The demand for standard platelet concentrates (PCs) has continued to increase in the recent years. Infusible platelet membranes (IPM) prepared from new or outdated human platelets have been developed as an alternative to standard PCs, with the additional advantage of long shelf life and increased viral safety. Reduction of HLA antigens on the IPM has been assigned as one of the probable advantages of this product. In re-examining this issue, we studied the existence of HLA class I on the surface of IPM microparticles. In comparison we also surveyed HLA expression on the surface of the naturally occurred platelet-derived microparticles (nPMPs) during 7 days storage. Intended for producing IPM, PCs obtained from Iranian blood transfusion organization were lysed; virally inactivated with wet heat in the presence of a heat stabilizer and then sonicated. IPMs were separated using centrifugation and liquid-stored in 4°C. The expression of HLA class I antigens was surveyed using flow cytometry technique. HLA molecules were present on the microparticles. Shedding of HLA antigens was demonstrated from the surface of the both liquid-stored IPM and nPMPs during storage. Storage of IPM in 4°C was accompanied with significant reduction of HLA molecules. It seemed that achievement of HLA-free IPM could be impossible unless chloroquine treated platelets were used to prepare these microvesicles.

Platelet transfusions: impact on hemostasis, thrombosis, inflammation and clinical outcomes

Platelet transfusion is one of the most crucial therapeutic approaches in Medicine. However, severe and fatal adverse reactions may develop. In addition to their important function in hemostasis, platelets' role in inflammation has become more evident. Recently, platelets are also recognized as the main source of circulating soluble CD40 ligand (sCD40L, (CD154)), which plays significant roles in hemostasis, platelet activation, clot stability, interactions with other cells, and upregulation of different mediators. In this review, we will briefly highlight the importance of platelet transfusion, its role in inflammatory and thrombotic transfusion reactions, and visit the most recent findings on sCD40L.