Current trends in platelet transfusions practice: The role of ABO-RhD and human leukocyte antigen incompatibility

Platelet transfusions have contributed to the revolutionary modern treatment of hypoproliferative thrombocytopenia. Despite the long-term application of platelet transfusion in therapeutics, all aspects of their optimal use (i.e., in cases of ABO and/or Rh (D incompatibility) have not been definitively determined yet. We reviewed the available data on transfusion practices and outcome in ABO and RhD incompatibility and platelet refractoriness due to anti-human leukocyte antigen (HLA) antibodies. Transfusion of platelets with major ABO-incompatibility is related to reduced posttransfusion platelet (PLT) count increments, compared to ABO-identical and minor, but still are equally effective in preventing clinical bleeding. ABO-minor incompatible transfusions pose the risk of an acute hemolytic reaction of the recipient that is not always related to high anti-A, B donor titers. ABO-identical PLT transfusion seems to be the most effective and safest therapeutic strategy. Exclusive ABO-identical platelet transfusion policy could be feasible, but alternative approaches could facilitate platelet inventory management. Transfusion of platelets from RhD positive donors to RhD negative patients is considered to be effective and safe though is associated with low rate of anti-D alloimmunization due to contaminating red blood cells. The prevention of D alloimmunization is recommended only for women of childbearing age. HLA alloimmunization is a major cause of platelet refractoriness. Managing patients with refractoriness with cross-matched or HLA-matched platelets is the current practice although data are still lacking for the efficacy of this practice in terms of clinical outcome. Leukoreduction contributes to the reduction of both HLA and anti-D alloimmunization

Central Retinal Vein Occlusion Secondary to Clomiphene Treatment in a Male Carrier of Factor V Leiden

We report a case of a 35-year-old previously healthy man treated with clomiphene for infertility, who presented with blurred vision in his left eye due to ocular vein occlusion as documented by fluorescein angiography. The patient was heterozygous for the factor V Leiden (FV Leiden) mutation and for the 1298 A-C polymorphism of the methylene-tetrahydrofolate reductase (MTHFR) gene. He was treated with clopidogrel and is now free of symptoms. Because congenital thrombophilia is a moderate risk factor for central retinal vein occlusion and the administration of clomiphene may trigger this process, we recommend screening of young patients for FV Leiden before clomiphene treatment

eNOS Gene Variants and the Risk of Premature Myocardial Infarction

BACKGROUND: Endothelial nitric oxide synthase (eNOS) as well as nitric oxide play an important role in the regulation of cardiovascular function. There are limited and controversial data regarding the impact of polymorphisms of eNOS gene that is implicated in the vasoconstrictive properties of the endothelium in the pathogenesis of premature myocardial infarction (MI)

Prevalence of Prothrombotic Polymorphisms in Greece

The aim of this study was to assess the prevalence of several polymorphisms in genes that are involved in several pathways such as hemostasis, fibrinolysis, platelet membrane receptor activity, endothelial integrity and function, lipid metabolism, and regulation of blood pressure in healthy subjects of Greek origin. Most of these polymorphisms are mainly associated with conditions such as venous thromboembolism and atherothrombosis, and their prevalence has not been studied yet in Greece. We tested 140 healthy individuals for factor V (FV)1691G/A, FV4070G/A, FII 20210G/A, factor XIII (FXIII) exon 2G/T, fibrinogen beta-455G/A, plasminogen activator inhibitor-1 (PAI-1)-675 4G/5G, human platelet antigens 1 (HPA1) a/b, apolipoprotein B (ApoB) 10708 G/A, apolipoprotein E (ApoE) E2, E3, and E4, angiotensin-converting enzyme (ACE) D/I, 5,10 methylenetetrahydrofolate reductase (MTHFR) 677C/T, and MTHFR 1298A/C polymorphisms using a PCR and reverse hybridization technique that detects all of them simultaneously. The allele frequencies observed are in accordance with those reported in other Caucasian populations and almost identical to those of East Mediterranean populations. This first report from Greece may serve as a baseline for planning further investigations of these polymorphisms in association with several clinical entities and for launching guidelines for patient testing of various disease settings in this population

Retinal vein occlusion: genetic predisposition and systemic risk factors

The role of systemic risk factors (age, smoking, diabetes, arterial hypertension) in the development of retinal vein occlusion (RVO) is well established. However, the association of RVO with genetic predisposition to thrombosis remains poorly understood. The aim of the study was to assess any possible additional effect of genetic predisposition to the already well known ‘classical’ risk factors of RVO in a cohort of elderly Greek patients. Fifty-one elderly patients with RVO and 51 healthy individuals matched for age and sex were evaluated for systemic risk factors (smoking, diabetes, dyslipidemia, arterial hypertension) and coagulation defects (lupus anticoagulant, natural inhibitors of coagulation). Additionally, genotyping was performed for mutations/polymorphisms involved in haemostasis such as: FV G1691A, FV G4070A, FIIG 20210A, MTHFR C677T and A1298C, PAI-1-675 4G/5G, F XIII exon 2G/T, EPCR A4600G and G4678C. We identified systemic risk factors in the majority of the patients Hypertension (P=0.001), dyslipidemia (P=0.029) and diabetes (P=0.01) are associated with RVO in the majority of the patients. The prevalence of prothrombotic risk factors was not significantly different in the patients with RVO compared to controls. Apart from systemic risk factors, genetic predisposition to thrombosis does not seem to have an important association with RVO in this group of elderly patients. Blood Coagul Fibrinolysis 24:279-283 (C) 2013 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins

Haemostatic profile of riboflavin-treated apheresis platelet concentrates.

BACKGROUND: The haemostatic activity of platelet concentrates (PCs) treated with pathogen reduction technology (PRT) remains a subject of debate. Our aim was to investigate the effect of Mirasol PRT on the haemostatic properties of PCs stored in plasma. MATERIAL AND METHODS: Untreated and Mirasol-treated platelets stored in plasma and derived from ten split double-dose apheresis PCs were evaluated in vitro on days 1, 3 and 5 post collection for functionality, microparticle procoagulation activity (MPA), endogenous thrombin potential (ETP), and haemostatic profile using rotational thromboelastometry (ROTEM). RESULTS: P-selectin expression was significantly higher in Mirasol-treated platelets compared with untreated counterparts on days 3 and 5 (p=0.003 and p=0.002, respectively). Clot strength, as shown by EXTEM maximum clot firmness (MCF), was significantly lower in the Mirasol-treated platelets at all time points (days 1, 3, 5) than in untreated platelets (p=0.009, p<0.001, p<0.001, respectively). There was a considerable increase in MPA over time (p<0.001) and this was significantly higher in the Mirasol-treated platelets on day 5 (p=0.015). A notable acceleration of decrease in ETP values was observed for Mirasol-treated PCs over time (p<0.001), with significant differences between PRT-treated and untreated PCs on days 3 and 5 (p=0.038 and p=0.019, respectively). Clot strength attenuation was significantly associated with pH reduction (p<0.001, Spearman’s rho: 0.84), increased microparticle procoagulant activity (p<0.001, Spearman’s rho: -0.75), and with decreased ETP (p<0.032, Spearman’s rho: 0.41). DISCUSSION: Increased platelet activation induced by PRT treatment leads to a decrease in in vitro haemostatic capacity as seen by reduced clot strength and thrombin generation capacity over time. The clinical relevance of this needs to be investigated

The Safety and Efficacy of Tranexamic Acid in Oncology Patients Undergoing Endoprosthetic Reconstruction and a ROTEM-Based Evaluation of Their Hemostatic Profile: A Pilot Study

Simple Summary Tranexamic acid can be an effective and safe way to reduce perioperative bleeding following an endoprosthetic reconstruction of a lower limb after a bone tumor resection. Tranexamic acid does not result in a complete shutdown of the fibrinolysis, supporting its safe use without increasing the risk of thromboembolic complications. Background: An endoprosthetic reconstruction in musculoskeletal oncology patients is associated with significant blood loss. The purpose of this study is to evaluate the safety and efficacy of tranexamic acid (TXA) for these patients and to assess any changes in their hemostatic profile using rotational thromboelastometry (ROTEM). Methods: A retrospective observational study was performed including 61 patients with primary or metastatic bone tumors who underwent surgery. Group A (n = 30) received both intravenous and local TXA whereas Group B (n = 31) was the control group. The primary outcomes were perioperative blood loss and blood unit transfusions and the secondary outcomes included the incidence of thromboembolic complications and a change in blood coagulability as reflected by ROTEM parameters. Results: The median difference in blood loss between the two groups was 548.5 mL, indicating a 29.2% reduction in the 72 h blood loss following TXA administration (p < 0.001). TXA also led to a reduced transfusion of 1 red blood cell (RBC) unit per patient (p < 0.001). The two groups had similar rates of thromboembolic complications (p = 0.99). The antifibrinolytic properties of TXA were confirmed by the significantly higher INTEM, FIBTEM and EXTEM LI60 (p < 0.001, p = 0.005 and p < 0.001, respectively) values in the TXA group. Conclusion: Tranexamic acid was associated with a significant reduction in perioperative blood loss and transfusion requirements without a complete shutdown of the fibrinolysis. Larger studies are warranted to assess the frequency of these outcomes in musculoskeletal oncology patients