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Blood Nov 2022Platelet transfusions are commonly administered for the prevention or treatment of bleeding in patients with acquired thrombocytopenia across a range of clinical... (Review)
Review
Platelet transfusions are commonly administered for the prevention or treatment of bleeding in patients with acquired thrombocytopenia across a range of clinical contexts. Recent data, including randomized trials, have highlighted uncertainties in the risk-benefit balance of this therapy, which is the subject of this review. Hemovigilance systems report that platelets are the most frequently implicated component in transfusion reactions. There is considerable variation in platelet count increment after platelet transfusion, and limited evidence of efficacy for clinical outcomes, including prevention of bleeding. Bleeding events commonly occur despite the different policies for platelet transfusion prophylaxis. The underlying mechanisms of harm reported in randomized trials may be related to the role of platelets beyond hemostasis, including mediating inflammation. Research supports the implementation of a restrictive platelet transfusion policy. Research is needed to better understand the impact of platelet donation characteristics on outcomes, and to determine the optimal thresholds for platelet transfusion before invasive procedures or major surgery (eg, laparotomy). Platelet transfusion policies should move toward a risk-adapted approach that does not focus solely on platelet count.
Topics: Humans; Platelet Transfusion; Thrombocytopenia; Hemorrhage; Blood Platelets; Platelet Count
PubMed: 35926105
DOI: 10.1182/blood.2022016558 -
British Journal of Haematology Apr 2017A low platelet count is a frequently encountered haematological abnormality in patients treated in intensive treatment units (ITUs). Although severe thrombocytopenia... (Review)
Review
A low platelet count is a frequently encountered haematological abnormality in patients treated in intensive treatment units (ITUs). Although severe thrombocytopenia (platelet count <20 × 10 /l) can be associated with bleeding, even moderate-degree thrombocytopenia is associated with organ failure and adverse prognosis. The aetiology for thrombocytopenia in ITU is often multifactorial and correcting one aetiology may not normalise the low platelet count. The classical view for thrombocytopenia in this setting is consumption associated with thrombin-mediated platelet activation, but other concepts, including platelet adhesion to endothelial cells and leucocytes, platelet aggregation by increased von Willebrand factor release, red cell damage and histone release, and platelet destruction by the complement system, have recently been described. The management of severe thrombocytopenia is platelet transfusion in the presence of active bleeding or invasive procedure, but the risk-benefit of prophylactic platelet transfusions in this setting is uncertain. In this review, the incidence and mechanisms of thrombocytopenia in patients with ITU, its prognostic significance and the impact on organ function is discussed. A practical approach based on the authors' experience is described to guide management of a critically ill patient who develops thrombocytopenia.
Topics: Biomarkers; Blood Coagulation; Critical Illness; Disease Management; Humans; Incidence; Platelet Count; Prognosis; Thrombocytopenia
PubMed: 27982413
DOI: 10.1111/bjh.14482 -
Current Opinion in Hematology Nov 2021This review highlights recent advancements in understanding the regulation of platelet numbers, focusing on mechanisms by which carbohydrates (glycans) link platelet... (Review)
Review
PURPOSE OF THE REVIEW
This review highlights recent advancements in understanding the regulation of platelet numbers, focusing on mechanisms by which carbohydrates (glycans) link platelet removal with platelet production in the bone marrow in health and disease.
RECENT FINDINGS
This review is focused on the role of carbohydrates, specifically sialic acid moieties, as a central mediator of platelet clearance. We discuss recently identified novel mechanisms of carbohydrate-mediated platelet removal and carbohydrate-binding receptors that mediate platelet removal.
SUMMARY
The platelet production rate by megakaryocytes and removal kinetics controls the circulating platelet count. Alterations in either process can lead to thrombocytopenia (low platelet count) or thrombocytosis (high platelet count) are associated with the risk of bleeding or overt thrombus formation and serious complications. Thus, regulation of a steady-state platelet count is vital in preventing adverse events. There are few mechanisms delineated that shed light on carbohydrates' role in the complex and massive platelet removal process. This review focuses on carbohydrate-related mechanisms that contribute to the control of platelet numbers.
Topics: Blood Platelets; Humans; Megakaryocytes; Platelet Count; Polysaccharides; Thrombopoiesis
PubMed: 34605444
DOI: 10.1097/MOH.0000000000000682 -
Haematologica Jun 2014
Topics: Age Factors; Aging; Humans; Platelet Count
PubMed: 24881040
DOI: 10.3324/haematol.2014.106260 -
Anaesthesiology Intensive Therapy 2015Heparin-induced thrombocytopenia (HIT) is a clinical immune-mediated syndrome; symptoms of HIT result from the development of arterial and venous thrombosis and are... (Review)
Review
Heparin-induced thrombocytopenia (HIT) is a clinical immune-mediated syndrome; symptoms of HIT result from the development of arterial and venous thrombosis and are correlated with the severity of the thrombocytopenia. In all patients receiving heparin preparations in intensive care units, platelet counts should be monitored every 2-3 days throughout therapy, particularly during days 4-14 when HIT is most likely to develop. The major screening tests should always involve a clinical assessment of HIT probability (4Ts or HEP scoring systems) and enzymatic immunoassays (IgG antibodies) for patients with a moderate to high risk of HIT. The full possibilities of such advanced diagnostic procedures are limited in Poland because functional tests are still not widely available. If the diagnosis is questionable, all heparin preparations should be withdrawn and an alternative method of anticoagulation instituted until HIT has been conclusively excluded. The use of new-generation anticoagulants (direct thrombin or Xa factor inhibitors) is currently considered the treatment of choice. Old-generation anticoagulants should not be administered (vitamin K antagonists) as they can aggravate thrombosis. If administered, their action should be reversed by vitamin K once HIT is confirmed. Antithrombotic therapy with "new" anticoagulants should be carried out at least until platelet counts return to the baseline values; the recommended duration of therapy is 4 weeks in patients with isolated thrombocytopenia or 4 months in those with thrombotic complications. Vitamin K antagonists should not be applied until the normal platelet count is restored (usually > 150 G L⁻¹). When the therapy with vitamin K antagonists is reintroduced, "old" antagonists should be administered simultaneously with a "new" anticoagulant for at least 5 days due to an initial decrease in protein C concentration concentration, provided that the therapeutic value of INR is maintained (> 2) for at least 2 days.
Topics: Animals; Anticoagulants; Drug Monitoring; Heparin; Humans; Platelet Count; Poland; Severity of Illness Index; Thrombocytopenia
PubMed: 25751293
DOI: 10.5603/AIT.2015.0006 -
Platelets Mar 2018The last decade has witnessed an explosion in the depth, variety, and amount of human genetic data that can be generated. This revolution in technical and analytical... (Review)
Review
The last decade has witnessed an explosion in the depth, variety, and amount of human genetic data that can be generated. This revolution in technical and analytical capacities has enabled the genetic investigation of human traits and disease in thousands to now millions of participants. Investigators have taken advantage of these advancements to gain insight into platelet biology and the platelet's role in human disease. To do so, large human genetics studies have examined the association of genetic variation with two quantitative traits measured in many population and patient based cohorts: platelet count (PLT) and mean platelet volume (MPV). This article will review the many human genetic strategies-ranging from genome-wide association study (GWAS), Exomechip, whole exome sequencing (WES), to whole genome sequencing (WGS)-employed to identify genes and variants that contribute to platelet traits. Additionally, we will discuss how these investigations have examined and interpreted the functional implications of these newly identified genetic factors and whether they also impart risk to human disease. The depth and size of genetic, phenotypic, and other -omic data are primed to continue their growth in the coming years and provide unprecedented opportunities to gain critical insights into platelet biology and how platelets contribute to disease.
Topics: Blood Platelets; Female; Humans; Male; Mean Platelet Volume; Platelet Count
PubMed: 28649937
DOI: 10.1080/09537104.2017.1317732 -
Frontiers in Immunology 2022Some degree of platelet index abnormality has been found clinically in the autoimmune thyroid disease (AITD), but the findings are not uniform. (Meta-Analysis)
Meta-Analysis
BACKGROUND
Some degree of platelet index abnormality has been found clinically in the autoimmune thyroid disease (AITD), but the findings are not uniform.
METHODS
The PubMed, Web of Science, Cochrane Library, and Embase databases were searched for relevant articles published up to August 16th, 2022, with no restrictions on the language of the articles. Reference lists of eligible articles were also searched. A random effect model was used to pool the standardized mean difference (SMD) and 95% confidence interval (95% CI) of platelet count (PLT), mean platelet volume (MPV), and platelet distribution width (PDW) between AITD patients and healthy controls, and subgroup analyses were performed.
RESULTS
A total of 19 articles with 6173 people (3824 AITD patients and 2349 healthy people) were included in the meta-analysis. The results showed that PLT and MPV values were significantly increased in AITD patients when compared with healthy people (SMD: 0.164, 95% CI: 0.044 to 0.285; SMD: 0.256, 95% CI: 0.013 to 0.500), while no significant difference was found in PDW between the AITD group and the control group (SMD: 0.060, 95% CI: -0.164 to 0.284). Subgroup analysis according to disease type and thyroid function revealed that for PLT, this difference was only found in the Hashimoto's thyroiditis (HT) and hypothyroid groups, but not in the Graves' disease (GD) and hyperthyroid groups. For MPV, the results were the opposite of those for PLT: MPV was significantly higher in the GD, hyperthyroid, and euthyroid groups than in the control group, but not in the HT and hypothyroid groups. Sensitivity analysis showed that the stability of the pooled MPV was not good. No publication bias was found.
CONCLUSIONS
PLT and MPV are significantly elevated in patients with AITD, with PLT being more significantly elevated in HT and hypothyroidism, and MPV being more significantly increased in GD and hyperthyroidism. Appropriate clinical attention can be paid to the thyroid function of patients when abnormal platelet indices are found, and conversely, the consequences of abnormal platelet parameters such as elevated MPV lead to an increased occurrence of cardiovascular events, which should also be addressed in the AITD population.
SYSTEMATIC REVIEW REGISTRATION
https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022341823.
Topics: Humans; Hashimoto Disease; Mean Platelet Volume; Platelet Count; Graves Disease; Hyperthyroidism; Hypothyroidism
PubMed: 36618418
DOI: 10.3389/fimmu.2022.1089469 -
JAMA Network Open Jan 2022Individuals with cancer often have an elevated platelet count at the time of diagnosis. The extent to which an elevated platelet count is an indicator of cancer is...
IMPORTANCE
Individuals with cancer often have an elevated platelet count at the time of diagnosis. The extent to which an elevated platelet count is an indicator of cancer is unclear.
OBJECTIVE
To evaluate the association of an elevated platelet count with a cancer diagnosis.
DESIGN, SETTING, AND PARTICIPANTS
This nested case-control study included Ontario residents enrolled in the provincial health insurance plan who had 1 or more routine complete blood count (CBC) tests performed between January 1, 2007, and December 31, 2017, with follow-up through December 31, 2018. Case patients were individuals with a new cancer diagnosis during the observation period. Eligible control individuals were cancer free before the date of diagnosis for a case patient to whom they were matched. One case patient was matched to 3 controls based on sex, age, and health care use patterns. Data were analyzed from September 24, 2020, to July 13, 2021.
EXPOSURES
Case patients and controls were assigned to 1 of 5 exposure groups based on age- and sex-specific platelet count distributions in the control population: very low (≤10th percentile), low (>10th to 25th percentile), medium (>25th to <75th percentile), high (75th to <90th percentile), and very high (≥90th percentile).
MAIN OUTCOMES AND MEASURES
Odds ratios (ORs) were estimated for specific cancer sites for each category of platelet count at intervals up to 10 years after a blood test.
RESULTS
Of the 8 917 187 eligible Ontario residents with a routine CBC record available, 4 971 578 (55.8%) were women; the median age at the first CBC was 46.4 years (IQR, 32.5-59.5 years). Among individuals with a routine CBC record available, 495 341 (5.6%) received a diagnosis of first primary cancer during the 10-year observation period. The OR for a solid tumor diagnosis associated with a very high platelet count vs a medium platelet count in the 6-month period before the diagnosis was 2.32 (95% CI, 2.28-2.35). A very high platelet count was associated with colon (OR, 4.38; 95% CI, 4.22-4.54), lung (OR, 4.37; 95% CI, 4.22-4.53), ovarian (OR, 4.62; 95% CI, 4.19-5.09), and stomach (OR, 4.27; 95% CI, 3.91-4.66) cancers. Odds ratios attenuated with increasing time from CBC test to cancer diagnosis.
CONCLUSIONS AND RELEVANCE
In this nested case-control study, an elevated platelet count was associated with increased risk of cancer at several sites. Our findings suggest that an elevated platelet count could potentially serve as a marker for the presence of some cancer types.
Topics: Adult; Biomarkers; Case-Control Studies; Female; Humans; Male; Middle Aged; Neoplasms; Ontario; Platelet Count
PubMed: 35015064
DOI: 10.1001/jamanetworkopen.2021.41633 -
Frontiers in Immunology 2022Platelet (PLT) engages in immune and inflammatory responses, all of which are related to the prognosis of critically ill patients. Although thrombocytopenia at ICU...
OBJECTIVE
Platelet (PLT) engages in immune and inflammatory responses, all of which are related to the prognosis of critically ill patients. Although thrombocytopenia at ICU admission contributes to in-hospital mortality, PLT is repeatedly measured during ICU hospitalization and the role of longitudinal PLT trajectory remains unclear. We aimed to identify dynamic PLT trajectory patterns and evaluate their relationships with mortality risk and thrombocytopenia.
METHODS
We adopted a three-phase, multi-cohort study strategy. Firstly, longitudinal PLT trajectory patterns within the first four ICU days and their associations with 28-day survival were tested in the eICU Collaborative Research Database (eICU-CRD) and independently validated in the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. Secondly, the relationships among PLT trajectory patterns, thrombocytopenia, and 28-day mortality were explored and validated. Finally, a Mortality GRade system for ICU dynamically monitoring patients (Mortality-GRID) was developed to quantify the mortality risk based on longitudinal PLT, which was further validated in the Molecular Epidemiology of Acute Respiratory Distress Syndrome (MEARDS) cohort.
RESULTS
A total of 35,332 ICU patients were included from three cohorts. Trajectory analysis clustered patients into ascending (AS), stable (ST), or descending (DS) PLT patterns. DS patients with high baseline PLT decline quickly, resulting in poor prognosis. AS patients have low baseline PLT but recover quickly, favoring a better prognosis. ST patients maintain low PLT, having a moderate prognosis in between ( = 1.26, 95% CI: 1.14-1.38, = 6.15 × 10; = 1.58, 95% CI: 1.40-1.79, = 1.41 × 10). The associations remained significant in patients without thrombocytopenia during the entire ICU hospitalization and were robust in sensitivity analyses and stratification analyses. Further, the trajectory pattern was a warning sign of thrombocytopenia, which mediated 27.2% of the effects of the PLT trajectory on 28-day mortality ( = 1.11, 95% CI: 1.06-1.17, = 9.80 × 10). Mortality-GRID well predicts mortality risk, which is in high consistency with that directly estimated in MEARDS ( = 0.98, = 1.30 × 10).
CONCLUSION
Longitudinal PLT trajectory is a complementary predictor to baseline PLT for patient survival, even in patients without risk of thrombocytopenia. Mortality-GRID could identify patients at high mortality risk.
Topics: Cohort Studies; Critical Illness; Humans; Intensive Care Units; Platelet Count; Respiratory Distress Syndrome; Thrombocytopenia
PubMed: 36059447
DOI: 10.3389/fimmu.2022.936662 -
Frontiers in Immunology 2023
Topics: Humans; Megakaryocytes; Blood Platelets; Platelet Count; Communicable Diseases
PubMed: 37056755
DOI: 10.3389/fimmu.2023.1175200