Platelet function to estimate the bleeding risk in autoimmune thrombocytopenia

Panzer, Simon; Rieger, Miriam; Vormittag, Rainer; Eichelberger, Beate; Dunkler, Daniela; Pabinger, Ingrid

doi:10.1111/j.1365-2362.2007.01855.x

Cited by 49 publications

(48 citation statements)

References 32 publications

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“…In contrast, we report that increased levels of P-selectin on the surface of unstimulated platelets and reduced TRAP-induced platelet activation in ITP patients are significantly associated with higher bleeding scores even after adjustment for platelet counts (Figure 3; supplemental Table 2). A likely explanation for the difference in findings is that we used whole blood flow cytometry to study platelet activation whereas Panzer et al 6,29 performed flow cytometric analysis on platelet-rich plasma, the preparation of which is prone to introduce artifactual platelet activation. 8 In a recent study, 7 van Bladel et al reported that pediatric chronic ITP patients with a severe bleeding phenotype demonstrated decreased platelet co-aggregation with normal donor platelets in response to phorbol myristate acetate, compared with patients with a mild bleeding phenotype.…”

Section: Discussionmentioning

confidence: 98%

“…27 Panzer et al reported an increased percentage of circulating P-selectin-positive platelets in adult chronic ITP patients 28 and that ITP patients with high platelet surface P-selectin in vivo showed reduced agonist-induced platelet activation. 29 Panzer et al subsequently reported 6 that P-selectin expression on circulating platelets of ITP patients did not correlate with bleeding score, whereas platelet count and von Willebrand factordependent platelet adhesion were inversely associated with bleeding score. In contrast, we report that increased levels of P-selectin on the surface of unstimulated platelets and reduced TRAP-induced platelet activation in ITP patients are significantly associated with higher bleeding scores even after adjustment for platelet counts (Figure 3; supplemental Table 2).…”

Section: Discussionmentioning

confidence: 99%

“…However, there are scant data addressing the question of whether tests of platelet function can predict bleeding in patients with ITP, 6,7 because most tests of platelet function are affected by thrombocytopenia. However, platelet function measured by whole blood flow cytometry is largely unaffected by the platelet count because individual platelets are analyzed one at a time.…”

Section: Introductionmentioning

confidence: 99%

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Platelet function tests, independent of platelet count, are associated with bleeding severity in ITP

Frelinger

Grace

Gerrits

et al. 2015

Blood

132

123

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Key Points• ITP patients differ in their tendency to bleed despite similarly low platelet counts, thereby confounding treatment decisions.• Platelet function tests, independent of platelet count, are associated with bleeding severity in ITP patients.Immune thrombocytopenia (ITP) patients with similarly low platelet counts differ in their tendency to bleed. To determine if differences in platelet function in ITP patients account for this variation in bleeding tendency, we conducted a single-center, cross-sectional study of pediatric patients with ITP. Bleeding severity (assessed by standardized bleeding score) and platelet function (assessed by whole blood flow cytometry) with and without agonist stimulation was evaluated in 57 ITP patients (median age, 9.9 years). After adjustment for platelet count, higher levels of thrombin receptor activating peptide (TRAP)-stimulated percent P-selectin-and activated glycoprotein (GP)IIb-IIIa-positive platelets were significantly associated with a lower bleeding score, whereas higher levels of immature platelet fraction (IPF), TRAP-stimulated platelet surface CD42b, unstimulated platelet surface P-selectin, and platelet forward light scatter (FSC) were associated with a higher bleeding score. Thus, platelet function tests related to platelet age (IPF, FSC) and activation through the protease activated receptor 1 (PAR1) thrombin receptor (TRAPstimulated P-selectin, activated GPIIb-IIIa, and CD42b), independent of platelet count, are associated with concurrent bleeding severity in ITP. These tests may be useful markers of future bleeding risk in ITP. (Blood. 2015;126(7):873-879)

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Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Platelet function tests, independent of platelet count, are associated with bleeding severity in ITP

Frelinger

Grace

Gerrits

et al. 2015

Blood

132

123

View full text Add to dashboard Cite

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“…1 Further, agonist inducible platelet activation has been shown to be negatively associated with both platelet counts and spontaneous platelet activation. 2 Recently, pediatric ITP patients with lower agonist inducible platelet activity were shown to have more severe bleeding than pediatric ITP patients with higher platelet activity and this association persisted after correction for platelet counts.…”

Section: Introductionmentioning

confidence: 99%

Platelet function in adult ITP patients can be either increased or decreased, compared to healthy controls, and is associated with bleeding risk

et al. 2016

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Objectives: To test whether, together with platelet count, platelet activity could be an important predictor of bleeding risk in immune thrombocytopenia (ITP) patients.Methods: Platelet activity was tested by flow cytometric measurement of agonist induced P-selectin expression and compared between 23 adult ITP patients and 22 healthy volunteers. Results: Platelet activity could be either increased or decreased in ITP patients, compared to healthy volunteers. In the lowest platelet count category, normal to low platelet activity was associated with the biggest increase in bleeding risk. Risk difference 80% (95% confidence interval: 45-115%) for <32 × 10 9 platelets/L. For higher platelet counts, there was no association of platelet activity with bleeding risk. Discussion: Increased platelet activity was associated with decreased bleeding risk, but only in patients with low platelet counts. Conclusion: Platelet activity can be a predictor of bleeding risk in ITP patients with low platelet counts.

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“…The practice of an activity with higher risk of trauma, such as contact sports, should not be considered low risk. In patients with unexpected bleeding, additional laboratory tests should be performed to identify platelet dysfunction [20] or an additional haemostatic abnormality e.g. underlying von Willebrand disease [21,22].…”

Section: Introductionmentioning

confidence: 99%

Diagnosis and management of chronic ITP: comments from an ICIS expert group

Grainger¹,

Godeau²,

Bussel

et al. 2010

Ann Hematol

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Immune thrombocytopenia (ITP) is a common disorder in children and adults. In a patient with newly diagnosed ITP, the treatment strategy is relatively well defined. Second-line treatments are more controversial, and the management of chronic ITP is even more so. During the 3rd ICIS Expert Meeting on Consensus and Development of Strategies in ITP, held in Basel on September 3-5, 2009, a group of experts were tasked with reaching a consensus on some frequently asked questions relating to diagnosis and management of children and adults with chronic ITP. The content of this article is designed to provide a practical support to trained haematologists in their care of patients with chronic ITP.

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Platelet function to estimate the bleeding risk in autoimmune thrombocytopenia

Abstract: Platelet adhesion correlates with bleeding symptoms, while the size of aggregates that are formed under high shear correlates with in vivo platelet activation. The determination of these parameters may assist in estimating an individual bleeding risk and thus a decision for treatment.

Cited by 49 publications

References 32 publications

Platelet function tests, independent of platelet count, are associated with bleeding severity in ITP

Platelet function tests, independent of platelet count, are associated with bleeding severity in ITP

Platelet function in adult ITP patients can be either increased or decreased, compared to healthy controls, and is associated with bleeding risk

Diagnosis and management of chronic ITP: comments from an ICIS expert group

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