Platelet Function Disorders in Bleeding Patients without Other Coagulopathies

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 4650-4650
Author(s):  
Francine R. Dembitzer ◽  
Ellinor I.B. Peerschke ◽  
Caroline Cromwell ◽  
Xiaofei Zhang ◽  
Louis M. Aledort
Keyword(s):  
Platelet Aggregation ◽  
Board Of Directors ◽  
Platelet Function ◽  
Coagulation Factor ◽  
Clinical History ◽  
Study Cohort ◽  
Advisory Committees ◽  
Normal Platelet ◽  
Platelet Function Disorders ◽  
Age Range

Abstract Introduction: We present a series of 105 patients referred for hematologic consultation to evaluate a clinical bleeding disorder. Little is known regarding the prevalence of non-genetic qualitative platelet disorders and which of these might respond to desmopressin. Methods: Patients were assessed over a two-year period, from December 2011 through December 2013. Patients, who were found to have neither von Willebrand's disease nor coagulation factor deficiencies, nor quantitative platelet defects, were tested for platelet function abnormalities by PFA-100 (Dade Behring, Marburg, Germany) and platelet aggregation and secretion studies using lumi aggregation (Chrono-Log Corp., Havertown, PA, USA). Selected patients with abnormal platelet function were given a trial of intravenous desmopressin to determine efficacy, and platelet function studies were repeated 2 hours later. Results: Of the 105 referred patients (26 males, age range 15-83 years; 79 females, age range 21-86 years), 67 with either normal (n=43) or abnormal (n=24) PFA-100 results were not evaluated further based on their clinical history and presentation. 18 patients with abnormal PFA-100 results, consisting of Collagen/ADP, Collagen/Epinephrine, or both, had platelet aggregation and secretion studies performed. 16 of these patients had abnormal platelet aggregation and secretion studies, while 2 patients had normal studies. In addition, 20 patients with normal PFA-100 results underwent platelet aggregation and secretion studies. Of these, 17 had abnormal platelet aggregation and secretion predominantly in response to two or more weak agonists, including ADP, epinephrine and/or arachidonic acid. Only 3 of these 20 patients had normal platelet aggregation and secretion. Of the 16 patients with both abnormal PFA-100 and abnormal platelet aggregation and secretion tests, 11 underwent subsequent pre- and post- desmopressin platelet function testing. 7 of the 11 patients showed improvement or complete normalization of at least one PFA-100 parameter, i.e., either Collagen/ADP, Collagen/Epinephrine, or both. However, results of platelet aggregation and secretion tests remained unchanged, irrespective of PFA-100 results. Conclusions: In the present study, platelet aggregation and secretion studies in patients with no other coagulopathies revealed platelet function defects in approximately 30% of the study cohort. Platelet function defects were in response to weak agonists, including ADP, epinephrine, and/or arachidonic acid.Our data support the recent SCC ISTH recommendations against the use of PFA-100 for platelet function screening.We recommend that the hematologist carefully assess the bleeding history, and, if significant, pursue platelet aggregation and secretion studies to identify potential platelet function defects. Disclosures Aledort: Baxter Healthcare: Membership on an entity's Board of Directors or advisory committees, Other: DSMB Participation; Kedrion BioPharma: Consultancy, Membership on an entity's Board of Directors or advisory committees.

Identification of Qualitative Platelet Disorders in Adolescent Women with Heavy Menstrual Bleeding

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 4922-4922
Author(s):  
Kristina M. Haley ◽  
Susan Lattimore ◽  
Cara McDavitt ◽  
Ayesha Khader ◽  
Colin Boehnlein ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Board Of Directors ◽  
Platelet Function ◽  
Research Funding ◽  
Blood Platelet ◽  
Bleeding Disorder ◽  
Advisory Committees ◽  
Adolescent Women ◽  
Platelet Disorder ◽  
Platelet Function Assays

Abstract Introduction: Nearly 40% of adolescent women experience heavy menstrual bleeding (HMB), and identifiable bleeding disorders are diagnosed in only 20-60% of these patients. We suspect that qualitative platelet disorders contribute to HMB, but are under-diagnosed. A pilot study was conducted to evaluate platelet function in adolescent women with HMB employing four novel, small-volume, whole blood platelet function assays. In addition, primary and secondary hemostasis, bleeding phenotype, and quality of life were assessed. Methods: Patients referred to the Young Women's Hematology Clinic at Oregon Health & Science University for evaluation of HMB were offered participation in the study. Participants underwent standard review of their medical and family history and physical exam. Standard lab evaluation included CBC, PT, PTT, fibrinogen, thrombin time, Von Willebrand Panel, PFA-100, and iron studies with platelet aggregation or phenotyping performed if clinically indicated. Using less than 0.5 mL of whole blood, platelet function was assessed with four novel platelet function assays: assessment of platelet activation, secretion, and aggregation was assessed by flow cytometry analysis, while platelet adhesion and aggregation was assessed under shear in a capillary tube. Quality of life (QOL) was assessed using the PedsQL tool. Bleeding phenotype was assessed with the ISTH Bleeding Assessment Tool (ISTH BAT). Menorrhagia was assessed with the Pictorial Bleeding Assessment Chart (PBAC), the Philipp Tool and the clinical history. Results: Nine participants have enrolled on study to date, with 2 completing the 3-month visit. The median age of the cohort was 16 years (14-18 years). Eight out of nine categorized their period as heavy, 6 also had epistaxis, and 7 reported excessive bruising. The median ISTH BAT score was 4 (3-7). Of the 7 patients who had a Philipp Score obtained, 5 were positive. Median PBAC score was 161 (64-196). Median ferritin was 13 ng/mL (4-65 ng/mL). Median QOL psychosocial score was 70 (68.36-88.25), comparable to that of pediatric patients with cancer. Of the 9 participants, 6 had platelet aggregation and phenotyping. Four participants did not receive a bleeding disorder diagnosis, 1 was diagnosed with Type 1 VWD, 1 was diagnosed with bleeding disorder, NOS, and 1 was diagnosed with Ehlers Danlos Syndrome. Two participants were diagnosed with a qualitative platelet disorder (QPD): one based on platelet aggregation and one based on thromboelastography. The four novel platelet function assays confirmed platelet function abnormalities in the participants diagnosed with QPD's (Figure 1&2). Impaired platelet response to agonist stimulation was also observed in participants with non-platelet disorder bleeding disorder diagnoses and in participants without a bleeding disorder diagnosis. Conclusions: In this pilot study, the etiology of HMB in adolescent women was evaluated with four novel platelet assays in addition to standard assays of hemostasis. A bleeding disorder diagnosis was not made with standard evaluations in 4 out of 9 participants. The novel assays detected platelet abnormalities not observed using currently available clinical labs, and confirmed the presence of abnormal platelet function in participants with abnormal platelet function testing. These assays require significantly less blood volume than currently available assays and expand investigation of platelet function to platelet adhesion and platelet interactions in whole and flowing blood. Further work is needed to determine the sensitivity and specificity of the novel assays in detecting platelet dysfunction. Continued investigation into the impact of HMB on the adolescent female population is needed. Disclosures Haley: CSL Behring: Honoraria; Baxalta: Membership on an entity's Board of Directors or advisory committees. Recht:Biogen: Membership on an entity's Board of Directors or advisory committees; CSL Behring: Membership on an entity's Board of Directors or advisory committees; Biogen: Research Funding; Genentech: Research Funding; Novo Nordisk: Research Funding; Baxalta: Research Funding; Novo Nordisk: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees.

Clot-On-A-Chip: A Microfluidic Device To Study Platelet Aggregation and Contractility Under Shear

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 2363-2363 ◽  
Author(s):  
Lucas Ting ◽  
Shirin Feghhi ◽  
Ari Karchin ◽  
Wes Tooley ◽  
Nathan J White ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Board Of Directors ◽  
Microfluidic Device ◽  
Platelet Function ◽  
Research Funding ◽  
Force Generation ◽  
Advisory Committees ◽  
Equity Ownership ◽  
Contractile Forces

Abstract Introduction In primary hemostasis, platelets adhere, activate, and aggregate at the wall of an injured vessel to form a hemostatic plug for the cessation of bleeding. After activation, platelets generate myosin-driven contractile forces to compact the size of the plug in order to reduce the space between platelets and prevent their disaggregation. Hemodynamic shear can be a major effector of platelet function in hemostasis, but its effect on the ability of platelets to produce contractile forces is an open question. Studying the dynamics of platelet aggregation and platelet force generation under hemodynamic shear can provide important insights into hemostasis and thrombosis. Method We have developed a microfluidic device that uses microscale blocks to induce platelet aggregation and microscale posts to measure platelet forces in a hemostatic plug. Whole human blood in heparin or citrate is pumped through a microfabricated chip containing microchannels with arrays of blocks and posts arranged along the bottom of a microchannel (Fig. 1). The surface of the blocks and posts are pre-coated with von Willebrand factor and type I collagen to allow for platelet adhesion. As blood is passes over a block, its rectangular shape induces a high shear rate that causes platelets to aggregate on its surface. A flexible micropost is situated behind each block. As platelets aggregate between the block and post, their contractile forces causes the post to bend toward the block. The deflection of the post is recorded under fluorescence microscopy and analyzed using quantitative image analysis of the videos. Since a microscale post bends like a cantilever beam, its deflection can be used to quantify the forces of platelets. Results Blebbistatin, a myosin inhibitor, was used to confirm that deflection of the posts by the platelets in heparinized blood was due to myosin activity. When blood was incubated with 2-MeSAMP, a P2Y12 antagonist, platelets were able to aggregate, but their ability to generate contractile forces was substantially reduced. This finding indicates that ADP activation is needed for platelet contractility under shear. The rate of hemodynamic shear was found to influence platelet function, for the rate of platelet aggregation and force generation were found to increase for blood sheared from 2000 to 12,000 s-1. Moreover, platelet aggregation and contractile forces were reduced when glycoprotein Ib-V-IX complex and integrin αIIbβ3 were inhibited with antibody AK2 and antibody fragment c7E3 Fab, respectively. When citrated blood was incubated with tissue plasminogen activator, platelets aggregate and produced contractile forces that increased steadily within the first ten minutes, but then the forces began to subside. Conclusions Our device can be used to study the role of hemodynamic shear in platelet function and gives insights into the role of platelet forces during hemostasis. Its microscale dimensions also allow us the study the biomechanics involved in the formation of a hemostatic plug during its early stages of growth and stability. Disclosures: White: Vidacare Corp: Honoraria; Stasys Medical Corp: Consultancy, Equity Ownership, Membership on an entity’s Board of Directors or advisory committees, Patents & Royalties; NIH: Research Funding; Coulter Foundation: Research Funding; Washington State Life Sciences Discovery Fund: Research Funding. Sniadecki:Stasys Medical Corporation: Equity Ownership, Founder Other, Membership on an entity’s Board of Directors or advisory committees.

scholarly journals Initial Evaluation of Adolescent Females Hospitalized with Heavy Menstrual Bleeding

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 1216-1216
Author(s):  
Lauren E Amos ◽  
Shannon L Carpenter
Keyword(s):  
Board Of Directors ◽  
Platelet Function ◽  
Adolescent Females ◽  
Bleeding Disorder ◽  
Diagnostic Evaluation ◽  
Heavy Menstrual Bleeding ◽  
Bleeding Disorders ◽  
Advisory Committees ◽  
Platelet Function Disorders ◽  
Von Willebrand

Abstract Background: Heavy menstrual bleeding (HMB) in adolescents can be severe and life-threatening. Up to 30% of young women who are hospitalized with anemia due to HMB have a bleeding disorder. Guidelines from the American College of Obstetrics and Gynecology (ACOG) and the National Heart, Lung, and Blood Institute (NHLBI) recommend evaluation for bleeding disorders in such patients. ACOG recommendations include testing for von Willebrand disease (VWD) and specify that consultation with a hematologist may help in interpreting results. NHLBI recommends testing for vWD be done in conjunction with a hematologist. As von Willebrand factor is an acute phase reactant, testing when patients are severely anemic and bleeding may not provide accurate results. ACOG guidelines do not include testing for platelet function disorders (PFD), though PFD may be as prevalent as VWD in females with HMB. Early and accurate diagnosis of bleeding disorders is important for health and quality of life, yet limited data exists on the diagnostic evaluation for bleeding disorders in adolescent females hospitalized for HMB. Objectives: To evaluate the diagnostic evaluation of bleeding disorders in adolescent females hospitalized for HMB. Methods: A retrospective, single center chart review of female patients aged 9-21 years hospitalized for HMB and anemia at a tertiary care children's hospital from January 1, 2000 until December 31, 2017 was done. HMB was defined as menses ≥7 days in length, use of 8 or more pads or tampons per day during menses, pictorial bleeding assessment chart (PBAC) score greater than 100, or symptomatic anemia. Patients were identified from our Hemophilia Treatment Center (HTC) registry, review of patients seen at a comprehensive clinic staffed by pediatric hematologists and gynecologists for adolescent females with HMB and bleeding disorders, and by an Electronic Medical Record (EMR) query of admission and discharge diagnoses of HMB and anemia. Data obtained included clinical features, diagnostic evaluation, and laboratory results. Results: 118 patients hospitalized for HMB and anemia were included. Inpatient Hematology consult or outpatient referral occurred in 68 (58%) of the patients; 60/68 (88%) had a bleeding disorder evaluation completed. 34 patients had a hematologic disorder. PFD was the most common (15/34; 44%) followed by VWD (9/34; 26%). 42% (50/118) of the patients did not have a Hematology consult or outpatient referral (Table 1). While hospitalized for HMB and anemia, 29 of the 50 patients had testing for vWD performed and only 4/29 (14%) had testing repeated as an outpatient once hemoglobin normalized. No patients tested for VWD while inpatient had results consistent with the diagnosis. Platelet function testing was performed in 10/50 patients using the platelet function analyzer (PFA-100) in 8 patients and platelet aggregometry in 2 patients. Conclusions: Despite national guidelines and the presence of known risk factors such as HMB since menarche and HMB causing severe anemia, the hematology service was not involved in the diagnostic process for a significant number of adolescent females. In these patients, testing often occurred while patients were hospitalized and was not repeated. Testing for platelet function disorders occurred infrequently and mainly consisted of the PFA-100 which lacks sensitivity and specificity. When patients were evaluated by Hematology and tested for bleeding disorders, a large proportion had a bleeding disorder, of which PFD were most common. This study demonstrates the need for standardization of the evaluation of adolescent females hospitalized for HMB. Guidelines should be updated to include testing for PFD. Hematologists should be involved when females are hospitalized for HMB and anemia. Disclosures Carpenter: Genentech Incorporated: Membership on an entity's Board of Directors or advisory committees; Nationwide Children's Hospital: Speakers Bureau; Bayer: Honoraria; Kedrion Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Novo Nordisk Pharmaceuticals, Inc: Consultancy; HEMA Biologics: Consultancy; American Academy of Pediatrics: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novo Nordisk: Consultancy; National Hemophilia Foundation (Impact Education): Speakers Bureau; Kane County State's Attorney: Consultancy; CSL Behring: Speakers Bureau; 4th Judicial District Attorney's Office- Colorado: Consultancy; Kedrion Biopharmaceuticals: Consultancy.

scholarly journals Surgery-Associated Bleeding Risk in Patients with Platelet Function Disorders - a Cross Sectional Study with the American Thrombosis and Hemostasis Network Dataset (ATHNdataset)

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 180-180
Author(s):  
Divyaswathi Citla Sridhar ◽  
Robert F. Sidonio ◽  
Dunlei Cheng ◽  
Sanjay Ahuja
Keyword(s):  
Board Of Directors ◽  
Platelet Function ◽  
Advisory Committees ◽  
Glanzmann Thrombasthenia ◽  
Risk Of Bleeding ◽  
Storage Pool ◽  
Dental Procedures ◽  
Platelet Function Disorders ◽  
Bleeding Episodes ◽  
Bernard Soulier Syndrome

Abstract Introduction: Platelet function disorders (PFDs) are a group of heterogenous bleeding disorders with varying bleeding phenotype. Intraoperative and post-operative bleeding are serious complications among patients with PFDs undergoing surgery. There are very few studies in literature that have specifically investigated surgery associated bleeding complications in PFDs. The aim of this study was to utilize a large national dataset to describe surgeries performed in patients with PFD, characterize the bleeding associated with these surgical procedures and outline the therapeutic approaches adopted. Methods: In this retrospective study, the ATHNdataset was queried for demographic data, PFD diagnosis, surgeries among patients with PFD, intraoperative and post-operative bleeding episodes and treatment. Descriptive statistics were used. The ATHNdataset captures information from patients with bleeding and clotting disorders from over 140 federally funded hemophilia and thrombosis treatment centers (HTCs) in the US. Patients authorize inclusion of their demographic and clinical information in this de-identified Health Insurance Portability and Accountability Act (HIPAA)-compliant data set. Results: From January 2010 to March 2020, the ATHNdataset captured 2767 patients with PFDs, of which 1769 (63.93%) were female and 998 (36.1%) were male, with 1393 patients between 0-18 years (50%) and 1374 (50%) adults >18 years. PFDs identified include 32 patients with Bernard Soulier syndrome (1.16%), 131 patients with Glanzmann thrombasthenia (4.7%), 4 patients with Gray platelet syndrome (0.14%), 29 patients with Hermansky Pudlak syndrome (1%), 1548 patients with storage pool deficiency (55.9%), and 1023 patients diagnosed as PFD (36.9%). A total of 3252 procedures were reported between 2010 and 2020; 1271 patients (46%) patients with at least one documented procedure. Figure 1 shows common procedures among patients with PFDs. Surgery-associated bleeding episodes (includes intraoperative and post-operative bleeds) were reported with 69 procedures (2.1%), which included intraoperative bleeds reported for 18 procedures (0.5%) and post-operative bleeds reported for 51 procedures (1.6%). Of the 60 procedures in patients with Glanzmann thrombasthenia, surgery-associated bleeding episodes were reported after 9 dental procedures (41%), 1 circumcision (25%) and 11 other surgeries/procedures (18.3%). Of the 6 procedures in patients with Bernard Soulier syndrome, no intraoperative or post-operative bleeding episodes were reported. Of 1688 procedures in patients with storage pool deficiency, surgery-associated bleeding episodes were reported after 26 dental procedures (1.5%) and 62 other surgeries/procedures (3.67%). No intraoperative or post-operative mortality was reported among these patients. Of 1272 patients who underwent at least 1 procedure, 646 patients (50.7%) received some form of treatment before/during/after a procedure. Among these 646 patients, 2794 exposure days of hemostasis medications were used before/during/after procedures. Among these, 49% were prior to the procedure, 0.7 % during the procedure and 49.5% after the procedure. Treatments used are shown in figure 2. Conclusion: Our study shows that patients with PFDs have a substantial risk of bleeding associated with surgery. Identifying the risk of bleeding by type and providing appropriate pre-surgical prophylaxis can decrease rates of surgery-associated bleeding in PFDs. Figure 1 Figure 1. Disclosures Sidonio: Sanofi, Takeda, Octapharma, Bayer, Biomain, Grifols, Kedrion, Genentech. Catalyst, Guardian Therapeutics, Novo Nordisk, Hema Biologics, Uniqure.: Consultancy, Honoraria. Ahuja: Genentech: Membership on an entity's Board of Directors or advisory committees; Takeda: Other: DSMB member ; XaTek, Inc: Patents & Royalties; Sanofi: Membership on an entity's Board of Directors or advisory committees.

scholarly journals The Secreted Tyrosine Kinase Vlk Is Essential for Normal Platelet Activation and Thrombus Formation

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 10-11
Author(s):  
Leila Revollo ◽  
Glenn Merrill-Skoloff ◽  
Karen De Ceunynck ◽  
James Dilks ◽  
Mattia Bordoli ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Tyrosine Kinase ◽  
Board Of Directors ◽  
Platelet Function ◽  
Secretory Pathway ◽  
Thrombus Formation ◽  
Extracellular Proteins ◽  
Advisory Committees ◽  
Extracellular Domains

Tyrosine phosphorylation of proteins secreted into the extracellular space has been observed in cell cultures and in vivo, yet little is known about the role that phosphorylation of extracellular proteins serves in modulating cell function. An important reason for the gap in our knowledge of the functional significance of extracellular protein phosphorylation has been the delay in identifying extracellular kinases. Within the last decade, however, bioinformatic strategies to identify kinases with signal peptides, coupled with biochemical approaches to characterize kinases in the secretory pathway, have described several kinases that phosphorylate secretory pathway and extracellular substrates. Of the known kinases containing signal sequences, Fam20B and VLK have been identified in platelets. VLK has been identified as a broadly expressed secretory pathway tyrosine kinase secreted from platelets in an activation dependent manner. Its role in platelet function, however, has not been previously studied. To understand the contribution of tyrosine phosphorylation of secreted factors and extracellular domains of transmembrane proteins in platelet function and thrombus formation, we generated mice whose platelets lacked VLK. Mice with megakaryocyte/platelet-specific VLK deficiency (Vlk-cKO) exhibited normal platelet abundance, volume and morphology, and tail clip bleeding times, but showed dramatic changes in platelet function in vitro and in vivo. In vivo, platelet accumulation was reduced by 90% in Vlk-cKO mice compared to control (Vlkf/f) littermates (P = 0.02) following laser-induced injury of cremaster arterioles (Figure). Likewise, fibrin generation was reduced in mice lacking platelet VLK by 62% (P = 0.009). In vitro, evaluation of resting and thrombin-stimulated VLK-deficient platelets demonstrated a significant decrease of several tyrosine phosphobands compared to control. Platelet function testing of VLK-deficient platelets (Figure) showed decreased platelet aggregation in response to stimulation with 100 µM AYPGKF, a PAR4 agonist, (Vlkf/f: 70+5.1%; Vlk-cKO: 23+8.0%) or 4 µg/mL collagen (Vlkf/f: 53+2.5%; Vlk-cKO: 27.5+2.9%). Dense and α-granule release in response to AYPGKF were also significantly decreased in platelets in which VLK had been silenced. In contrast, Vlk-cKO platelets aggregated normally in response to either 10 µM, 40 µM, or 100 µM ADP, and the aggregation defect in response to low doses of AYPGKF was reversed by subthreshold concentrations (2.5 µM) of ADP. Furthermore, stimulation with high-dose 150 µM AYPGFK or 5 U/ml thrombin resulted in comparable platelet function and ATP secretion in control and Vlk-cKO platelets respectively, ruling out a storage pool defect. Taken together, these results suggest that a dense granule secretion defect contributes to the decrease in platelet aggregation observed in platelets in which VLK is absent. In human platelets, tyrosines phosphorylated in secreted and extracellular domains of transmembrane proteins implicated in the regulation of platelet function were identified by mass spectroscopy analysis. Extracellular proteins or proteins with phosphosites that mapped to extracellular domains included ectonucleoside triphosphate diphosphodydrolase 6 [ENTPD6], platelet basic protein, integrin αIIß, and multimerin-1. These studies demonstrate that the secretory pathway tyrosine kinase VLK is critical for stimulus dependent platelet aggregation and thrombus formation, and provide the first evidence that secreted kinases contribute to platelet function. Disclosures De Ceunynck: Sanofi: Current Employment. Dilks:PlateletBiogenesis: Current Employment. Peters:PlateletBiogenesis: Current Employment. Noetzli:Anylam: Current Employment. Rosen:Keros Therapeutics: Membership on an entity's Board of Directors or advisory committees. Italiano:PlateletBioGenesis: Consultancy, Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding. Flaumenhaft:STRM.Bio: Membership on an entity's Board of Directors or advisory committees; PlateletDiagnostics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; QuercisPharma: Membership on an entity's Board of Directors or advisory committees.

A History of Abnormal Bleeding Correlates with Platelet Dysfunction in Aggregation Studies but Not PFA-100 Analyses

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 3447-3447 ◽  
Author(s):  
Dharmesh Gopalakrishnan ◽  
Heesun J Rogers ◽  
Paul Elson ◽  
Keith R. McCrae
Keyword(s):  
Flow Cytometry ◽  
Arachidonic Acid ◽  
Platelet Aggregation ◽  
Board Of Directors ◽  
Platelet Function ◽  
Bleeding Event ◽  
Advisory Committees ◽  
History Of ◽  
Abnormal Bleeding ◽  
Platelet Release

Abstract Introduction:In this retrospective medical records-based study we analyzed the association between abnormal spontaneous or procedure-related bleeding and patterns of abnormality in tests of platelet function. Commonly used platelet function tests include Platelet Function Analyzer -100 Closure Times (PFA-100 CT), platelet aggregation testing using Light Transmission Aggregometry (LTA), and platelet dense granule release assay (by lumi-aggregometry). Other related tests include Von Willebrand factor (VWF) analysis, platelet flow-cytometry for cell surface glycoprotein expression, and electron microscopy. LTA in our center uses five different agonists - ADP, arachidonic acid, collagen, epinephrine and ristocetin, while lumi-aggregometry is performed using four agonists - ADP, arachidonic acid, collagen and epinephrine. Methods:This study included 497 patients who had platelet aggregation testing done using LTA between August 2008 and August 2013. Sixty-nine percent (n = 354) of these patients had a history of abnormal bleeding. Since the data were not normally distributed, Wilcoxon rank-sum test (for continuous variables) and Fisher's exact test (for categorical variables) were used wherever appropriate. P value of < 0.05 was considered as significant. Results:Of the patients with a history of abnormal bleeding, 81% had spontaneous bleeding, 29% had surgery/procedure-related bleeding, and 13% had history of both types of abnormal bleeding. Three hundred nine of these patients had a recent (< 4 weeks) bleeding event. Abnormal bleeding, recent or historical, was found to associate significantly with impaired platelet aggregation, as well as platelet release in response to ADP, arachidonic acid, collagen or epinephrine (P<0.001 for all). Abnormal aggregation and release in response to ≥2 different agonists was also significantly associated with abnormal bleeding, as was the total number of abnormalities on the aggregation and release panel (P<0.001). A history of a recent bleeding event (<4 weeks) was found to be associated with reduced aggregation in response to arachidonic acid (P = 0.001), impaired aggregation and release in response to collagen (P =0.04 and <0.001 respectively), and reduced platelet release in response to epinephrine (P = 0.005). Recent bleeding also correlated with the total number of abnormalities in the aggregation (P = 0.002) and release panels (p =0.03). No significant association was found between a history of abnormal bleeding (either recent or historical) and prolonged PFA-100 closure times (collagen/ADP or collagen/epinephrine), or any abnormality in VWF analyses or platelet flow-cytometry studies. Conclusions:While PFA-100 closure times, VWF analyses and platelet flow-cytometry panel failed to show an association with abnormal bleeding (historical or recent), impaired platelet aggregation or release in response to several agonists was found to correlate with abnormal spontaneous and/or procedure-related bleeding, recent as well as historical, suggesting that platelet aggregation and release assays may be useful in diagnosis of a bleeding diathesis in patients with an appropriate clinical history Disclosures McCrae: Halozyme: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Syntimmune: Consultancy; Momenta: Consultancy.

Ristocetin-Induced Platelet Aggregation for Monitoring of Bleeding Tendency in Ibrutinib-Treated Patients with Chronic Lymphocytic Leukemia

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 718-718 ◽  
Author(s):  
Lukas Kazianka ◽  
Christa Drucker ◽  
Cathrin Skrabs ◽  
Philipp Bernhard Staber ◽  
Edit Anna Porpaczy ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Board Of Directors ◽  
Platelet Function ◽  
Research Funding ◽  
Bleeding Event ◽  
Normal Subjects ◽  
Lymphocytic Leukemia ◽  
Bleeding Tendency ◽  
Bleeding Events ◽  
Advisory Committees

Abstract Background. Inhibition of Bruton´s tyrosine kinase (BTK) with the small molecule ibrutinib has significantly improved the survival of patients with chronic lymphocytic leukemia (CLL). BTK is also expressed in platelets. Collagen- and von Willebrand Factor (vWF)-dependent (ristocetin-induced) impairment of platelet function has recently been described (Levade M et al., Blood 2014, 124:3991-5;Kamel S et al., Leukemia 2015, 29:783-787) . Bleeding events were observed in 61% of patients in a recently published 3 year follow-up (Byrd JC et al., Blood 2015, 125:2497-2506). Bleeding under ibrutinib is generally mild (CTC grade 1-2 corresponding to spontaneous bruising or petechiae), but grade 3 or 4 bleeding can be observed, particularly after trauma. We hypothesized that quantitative assessment of platelet aggregation in ibrutinib CLL patients could help (1) to predict bleeding tendency, and (2) to guide patients through invasive procedures. Patientsand Methods. Twenty-four adult patients with previously treated CLL (16 male/8 female, median age 67 years, range 55-84) received ibrutinib orally at a planned dose of 420mg/day and were regularly monitored and thoroughly investigated for bleeding tendency. The median time on ibrutinib was 7.5 months, (range 1-27). Bleeding events (any CTC grade) occurred in 13 (54%) and dose-reductions to 280 (N=12) or 140mg (N=3) (for bleeding, infections, or neutropenia) were made in 15 (63%) of patients during a median observation period of 5 months (range 1-12). Bleeding was observed in 4 of 6 patients with concomitant anticoagulation. Of note, only 1 of the 24 patients had a CTC grade 3 bleeding event, and no grade 4 or 5 events were observed. Ristocetin-induced platelet aggregation (RIPA, herein referred to as RCoF) was quantitatively measured in fresh hirudin-blood by whole blood aggregometry with a Multiplate® Analyzer (Roche Diagnostics). Platelet aggregation was expressed in AUC units (U) (normal range 98-180U). Controls included normal subjects (N=53). Consecutive samples before and during treatment were available in all patients. Statistical methods comprised t-Test and ANOVA using SAS. Results. Ristocetin-induced platelet aggregation was already diminished before ibrutinib treatment (median 51 RCoF U) when compared to normal controls (Table 1). This is likely due to lower platelet counts in CLL patients influencing overall platelet aggregability (Hanke AA et al., Eur J Med Res 2010, 15:214-219). During ibrutinib treatment, platelet aggregation was substantially impaired (median of 22U). A direct comparison of available paired samples in 5 patients showed a significant decrease after ibrutinib initiation (51 to 14.5U; p=0.0028). Of note, significantly lower values were measured at visits when bleeding events were documented (N=34) compared to patient visits without bleeding tendency (N=70) (median 13 vs. 42U; p<0.001). The median RCoF value was lower in patients with CTC grade > 2 (N=10) vs. <2 bleeding (11 vs. 14U). Similar results were obtained for collagen-dependent platelet function (bleeding vs. no bleeding: 17 vs. 19.5U; p=0.002). RCoF values were correlated with platelet count (r2 =0.34; p<0.0001) at median values of 103 vs. 138 G/L in patients with or without bleeding, respectively. There was also a significant difference between the lowest RCoF values in individual patients with or without bleeding (7.5 vs. 16.5U; p=0.027) (Figure 1). No bleeding event was observed in patients whose lowest RCoF value was greater than 25U. Long-term kinetics of vWF-dependent platelet function was assessed in 7 patients and corresponded with ibrutinib dose. When ibrutinib was stopped, recovery of RCoF to greater than 70U was observed in as little as 48hours, suggesting a short time to normalization of platelet function. Conclusion. These data indicate that quantitative assessment of vWF-dependent platelet function in ibrutinib treated patients may serve to monitor therapy particularly in the setting of bleeding tendency, anticoagulation, or planned invasive procedures. Further evaluation of platelet function as a pharmacodynamic marker seems warranted. Figure 1. VWF-dependent platelet function (RCoF) in normal subjects or CLL patients before and during ibrutinib treatment with or without bleeding. Figure 1. VWF-dependent platelet function (RCoF) in normal subjects or CLL patients before and during ibrutinib treatment with or without bleeding. Figure 2. Lowest RCoF values in individual patients with or without bleeding. Figure 2. Lowest RCoF values in individual patients with or without bleeding. Disclosures Staber: Genactis: Research Funding; Janssen: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Takeda-Millenium: Research Funding; Karyopharm: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Roche: Consultancy, Honoraria; Morphosys: Consultancy, Honoraria. Pabinger:Boehringer Ingelheim: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Bayer: Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees; CSL Behring: Membership on an entity's Board of Directors or advisory committees, Other: Travel support, Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees; Baxter: Membership on an entity's Board of Directors or advisory committees. Jilma:True North Therapeutics, Inc.: Consultancy, Research Funding. Jaeger:Hoffmann La Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; True North Therapeutics, Inc.: Research Funding.

Evaluation of the Gene Encoding Calcium Diacylglycerol Guanine Nucleotide Exchange Factor I (CalDAG-GEFI) in Human Patients with Congenital Qualitative Platelet Disorders.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 5078-5078
Author(s):  
John Puetz ◽  
Mary Boudreaux
Keyword(s):  
Platelet Aggregation ◽  
Platelet Function ◽  
Guanine Nucleotide ◽  
Nucleotide Exchange ◽  
Factor I ◽  
Normal Platelet ◽  
Guanine Nucleotide Exchange ◽  
Nucleotide Exchange Factor ◽  
Platelet Function Disorders ◽  
Mucocutaneous Bleeding

Abstract Abstract 5078 Normal platelet function is dependent on an orchestrated series of interactions resulting in primary hemostasis. Dysfunction in any step of platelet activation and aggregation results in abnormal platelet function and abnormal mucocutaneous bleeding. Defects in agonist/receptor interactions, membrane phospholipid and cytoskeleton structure, signal transduction, storage pool content and release have all been described. While some congenital qualitative platelet function disorders such as Bernard-Soulier syndrome or Glanzmann thrombasthenia are well characterized at the molecular and genetic level, the majority of congenital platelet function disorders are not. Recently, insights into the molecular and genetic causes of platelet signal transduction and secretion pathway disorders have been found in animals. Dogs and cattle with recurrent abnormal mucocutaneous bleeding symptoms and abnormal in vitro platelet aggregation have been found to be caused by a mutation in the calcium-diacylglycerol guanine nucleotide exchange factor I (CalDAG-GEFI) gene. Genetic ablation of CalDAG-GEFI in mice has resulted in abnormal platelet function and bleeding. Polymorphisms in the human CalDAG-GEFI gene have been linked to Kindlin-3/ FERMT3 mutations resulting in a leukocyte adhesions defect associated with platelet dysfunction (LAD-III or LAD-1/variant syndrome). To date, mutations in the CalDAG-GEFI gene in humans associated with abnormal platelet function and bleeding have not been described. To determine if mutations in the human CalDAG-GEFI gene are associated with abnormal mucocutaneous bleeding and platelet aggregation dysfunction, we have begun sequencing the CalDAG-GEFI gene in human patients with a congenital qualitative platelet function disorder of unknown etiology. As control groups, we will also evaluate the CalDAG-GEFI gene sequence of unaffected family members and unrelated blood donors known to have normal platelet aggregation. Preliminary results of our analysis will be presented. Disclosures No relevant conflicts of interest to declare.

scholarly journals Comparison of LTA Versus Wbila in Pediatric Patients with Suspected Platelet Function Disorders

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 3762-3762
Author(s):  
Abigail Wax ◽  
Bhavia Doshi ◽  
Abinaya Arulselvan ◽  
Amrom Obstfeld ◽  
Michele P. Lambert
Keyword(s):  
Board Of Directors ◽  
Platelet Function ◽  
Pediatric Patients ◽  
Young Patients ◽  
Patient Characteristics ◽  
Serotonin Release ◽  
Advisory Committees ◽  
Platelet Function Disorders ◽  
Pediatric Populations ◽  
Abnormal Results

Abstract Background Diagnosis of platelet function disorders in pediatric patients is complicated by difficulties identifying at risk patients (due to young age, fewer hemostatic challenges) (Gresele, Journal of Thrombosis and Haemostasis, 2015), large quantities of blood required for standard testing, and inability to use large gauge needles to perform phlebotomy increasing the probability of false positive results. Diagnostic testing for pediatric platelet disorders has recently shifted from Light Transmission Aggregometry (LTA) with serotonin release to Whole Blood Impedance Lumi-Aggregometry (WBILA). There is a paucity of literature comparing LTA and WBILA and few studies examining bleeding assessment tools in exclusively pediatric populations. LTA is widely studied and considered the gold standard of platelet testing. However, the newer and less validated WBILA has a lower blood volume requirement making it potentially more suitable for very young patients in need of testing. Therefore, there is a significant need to validate results from WBILA testing to be able to perform platelet testing on young patients. Aims The study purpose was to analyze lab testing results and patient characteristics for patients that have had WBILA or LTA with serotonin release and compare results across testing platforms. We also compared performance characteristics for patients with access to both methods. Further, we compared Bleeding Assessment Tool (BAT) scores, age distributions and types of testing results and their occurrences for both types of testing. Methods Medical and laboratory records of children evaluated at the Children's Hospital of Philadelphia and at the Hospital of the University of Pennsylvania that were referred for a variety of causes from 1/1/2016 until 6/30/2018 were examined. Males and females referred for concerns for bleeding who are age 2 months to 21 years at time of evaluation were included. In late 2016 the coagulation laboratory at CHOP validated WBILA. Prior to this, patients were tested using LTA. Patient history and demographic information, indication for testing, aggregometry findings and final diagnosis were compared prior to and after this transition. Medical records were used to derive a bleeding score. Approximately 300 records were reviewed. Results For LTA with serotonin release, ages were distributed bimodally with peaks at 6 years and 16 years with an average of 10.6 years (SD=5.4 years). The most frequent indications for testing were epistaxis (24%) and easy bruising (20%). For WBILA, ages were distributed bimodally with peaks at 35 months and 15 years with an average of 8.6 years (SD=5.5 years). The most frequent indications for testing were epistaxis (27%) and family history (17%). Average age of patients tested with WBILA was significantly lower than LTA with serotonin release (p=0.0013). No difference in distribution or average BAT scores was seen between patients tested with LTA and WBILA. The percent of abnormal results for cases with LTA testing was 32% versus 27% for WBILA cases, a difference that was not statistically significant. This suggests that the tests have similar diagnostic performance. Additionally, there is a trend towards an association between higher BAT scores and abnormal test results, but not significantly due to few abnormal cases. Finally, comparison of WBILA with LTA results showed that for the 9 patients with both studies, 4 had normal WBILA after borderline abnormal LTA results and 5 had congruent findings. Conclusions Our data highlight the differences in results and patient characteristics between LTA and WBILA testing. The most significant difference between the two tests was age distribution, with LTA, which requires more blood, being performed in older patients. In examining test performance, our analysis of BAT scores suggests that in our population a higher BAT score may be associated with higher probability of abnormal result, but differences in scores are small and make it hard to differentiate patients appropriate for testing based on bleeding scores alone. Our rate of abnormal results is similar to that of other populations, and highlights the difficulty of diagnosis in pediatric populations. Based on the consistent frequencies of abnormal findings across test types and the analysis of BAT scores, WBILA may be an acceptable alternative to LTA with serotonin release in young patients needing evaluation for platelet function defects. Disclosures Doshi: Bayer: Research Funding. Lambert:Rigel: Consultancy; Summus: Consultancy; Shionogi: Consultancy; Novartis: Membership on an entity's Board of Directors or advisory committees; Educational Concepts in Medicine: Consultancy; Bayer: Membership on an entity's Board of Directors or advisory committees; CSL: Consultancy; Sysmex: Consultancy; Amgen: Membership on an entity's Board of Directors or advisory committees.

scholarly journals A Multi-Institution Retrospective Study to Assess Bleeding Phenotype Among Patients with Platelet Function Disorders

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 3033-3033
Author(s):  
Divyaswathi Citla Sridhar ◽  
Robert F. Sidonio ◽  
Michael Silvey ◽  
Dunlei Cheng ◽  
Sanjay Ahuja
Keyword(s):  
Retrospective Study ◽  
Board Of Directors ◽  
Platelet Function ◽  
Burden Of Illness ◽  
Heavy Menstrual Bleeding ◽  
Menstrual Bleeding ◽  
Advisory Committees ◽  
Post Surgery ◽  
Platelet Function Disorders ◽  
Bleeding Episodes

Abstract Introduction: Platelet function disorders (PFD) clinically manifest with wide variability in mucocutaneous bleeding and significant hemorrhage post-surgery or trauma. The overall prevalence of PFD is not known, as there have not been large population-based studies. Treatment of these patients vary based on their bleeding phenotype. Additionally, the exact bleeding phenotype of many qualitative platelet defects are not well described in literature. This study aims to describe the bleeding phenotype among patients with different (PFD). Methods: This is a retrospective study among patients with PFD conducted at 3 Hemophilia Treatment centers - HOG Center for Bleeding and Clotting Disorders of CHOA, Children's Mercy hospital HTC and Rainbow babies & Children's hospital HTC. Institutional IRB approval was obtained at all 3 institutions. We collected data on demographics, bleeding symptoms at presentation, bleeding episodes, management of these bleeds over a 6-year time period (2015-2020). Results: We identified 131 patients with PFDs at 3 institutions. This included 67 males (51.2%) and 64 females (48.8%). Among 131 patients, 72 patients (55%) had a defect in platelet agonist interaction/receptor defect (ADP/Epinephrine/Collagen/TXA2/Arachidonic acid), 37 patients (28.2%) had delta storage pool defect, 8 patients (6.1%) had Glanzmann thrombasthenia, 7 patients (5.3%) had a platelet release defect, 3 patients (2.3%) with an alpha granule defect, 2 patients (1.5%) with Bernard Soulier syndrome and 1 patient (0.76%) with Wiskott Aldrich syndrome. The most common bleeding symptoms at presentation were epistaxis (40.4%), followed by easy bruising (31.3%), heavy menstrual bleeding (15.2%), gum bleeding (6.87%) and gastrointestinal bleeding (4.58%). From 2015-2020, a total of 162 bleeds were documented, and 68 patients (51.9%) with at least 1 documented episode of bleeding. 67.2% of these bleeds were spontaneous, 12.3% were secondary to trauma, 4.9% after a dental procedure, 2.5% after surgery and 0.6% after child birth. The most common type of bleeding episode in diagnosed patients included epistaxis (50%), heavy menstrual bleeding (17.9%), skin/soft tissue bleed (5.5%), gastrointestinal (5.5%) and dental/tooth related (4.9%). 93 bleeding episodes (57.4%) required some form of treatment in various settings - home (73%), clinic (15%), emergency room (7.5%), hospitalization (14%) and ICU stay (2%). Treatments included antifibrinolytics (68.8%), recombinant factor VIIa (11.8%), desmopressin (9.6%), hormonal therapy (9.6%) and platelet transfusions (5.3%). Conclusions: Our study helps characterize the bleeding phenotype and management in patients with various PFD. This data is crucial in understanding the burden of illness among different types of PFD, and to understand health care utilization to better serve the needs of these poorly characterized patients. Disclosures Sidonio: Sanofi, Takeda, Octapharma, Bayer, Biomain, Grifols, Kedrion, Genentech. Catalyst, Guardian Therapeutics, Novo Nordisk, Hema Biologics, Uniqure.: Consultancy, Honoraria. Silvey: Genentech: Speakers Bureau; Sanofi Genzyme: Membership on an entity's Board of Directors or advisory committees. Ahuja: XaTek, Inc: Patents & Royalties; Sanofi: Membership on an entity's Board of Directors or advisory committees; Takeda: Other: DSMB member ; Genentech: Membership on an entity's Board of Directors or advisory committees.

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