216 Does Aortic Stenosis Effect Platelet Closure Time and Von Willebrand Factor Activity?

BackgroundAbnormal platelet function is associated with increased bleeding risk. Limited evidence suggests that platelet dysfunction is a cause of bleeding in patients with aortic stenosis (AS).Method40 patients with degenerative AS underwent detailed haematological assessment. Platelet closure time...

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Veröffentlicht in:Heart (British Cardiac Society) 2016-06, Vol.102 (Suppl 6), p.A143
Hauptverfasser: Choudhary, Ferrah, Kirby, Richard, Peter, Christina, Henderson, Robert
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creator Choudhary, Ferrah
Kirby, Richard
Peter, Christina
Henderson, Robert
description BackgroundAbnormal platelet function is associated with increased bleeding risk. Limited evidence suggests that platelet dysfunction is a cause of bleeding in patients with aortic stenosis (AS).Method40 patients with degenerative AS underwent detailed haematological assessment. Platelet closure time (PCT) in seconds, was measured from a citrated blood sample by a PFA 100 benchtop analyser. In the presence of standardized flow conditions and collagen and ADP agonists, high shear rates are created, leading to aggregation of platelets and subsequent occlusion at the aperture site. The PCT is recorded as the time taken for the aperture occlusion to develop. Mean platelet volume (MPV) and platelet count (as per the impedance method) were measured from an EDTA sample by a XE2100 analyser. Von Willebrand factor activity was assessed with collagen binding assay (vWF:CB). Each patient completed a questionnaire to document use of antiplatelet therapy (with aspirin/clopidogrel) and bleeding events (using the ISTH bleeding questionnaire).ResultsOf the 40 patients, 8 had mild AS, 23 moderate AS and 9 severe AS. The average age was 74.9 years (range 39–97) and 47.5% were male. All patients had a normal MPV. A low platelet count was noted in 3 patients and all had an associated prolonged PCT. VWF activity was abnormal in 60% (n = 24: 5 mild AS, 12 moderate, 7 severe) but there was no correlation with AS severity.Overall, 25 patients (62.5%) had a prolonged PCT, including 5 patients (1 mild AS, 1 moderate AS and 3 severe AS) with significant bleeding events (2 patients with gastrointestinal bleeding and 3 with epistaxis). All bleeding events occurred within 3 months of the haematological assessment and in 2 cases were ongoing when the patient completed the questionnaire. Only 1 patient with normal PCT had significant bleeding. A higher PCT was associated with more severe AS (p = 0.002, Table 1) and with the use of antiplatelet therapy (p = 0.043). Patients without antiplatelet therapy (n = 18) had a mean PCT of 126.5 (SD 36.94) vs patients on antiplatelet therapy, mean PCT of 174.5 (SD 82.15). There was no statistically significant relationship between PCT and vWF activity (p = 0.16).ConclusionThis study demonstrates that PCT is associated with AS severity but this association may be partly explained by an excess of antiplatelet therapy use in patients with severe AS. In this small sample there was no association between platelet closure time and abnormal vWF activity. On
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Limited evidence suggests that platelet dysfunction is a cause of bleeding in patients with aortic stenosis (AS).Method40 patients with degenerative AS underwent detailed haematological assessment. Platelet closure time (PCT) in seconds, was measured from a citrated blood sample by a PFA 100 benchtop analyser. In the presence of standardized flow conditions and collagen and ADP agonists, high shear rates are created, leading to aggregation of platelets and subsequent occlusion at the aperture site. The PCT is recorded as the time taken for the aperture occlusion to develop. Mean platelet volume (MPV) and platelet count (as per the impedance method) were measured from an EDTA sample by a XE2100 analyser. Von Willebrand factor activity was assessed with collagen binding assay (vWF:CB). Each patient completed a questionnaire to document use of antiplatelet therapy (with aspirin/clopidogrel) and bleeding events (using the ISTH bleeding questionnaire).ResultsOf the 40 patients, 8 had mild AS, 23 moderate AS and 9 severe AS. The average age was 74.9 years (range 39–97) and 47.5% were male. All patients had a normal MPV. A low platelet count was noted in 3 patients and all had an associated prolonged PCT. VWF activity was abnormal in 60% (n = 24: 5 mild AS, 12 moderate, 7 severe) but there was no correlation with AS severity.Overall, 25 patients (62.5%) had a prolonged PCT, including 5 patients (1 mild AS, 1 moderate AS and 3 severe AS) with significant bleeding events (2 patients with gastrointestinal bleeding and 3 with epistaxis). All bleeding events occurred within 3 months of the haematological assessment and in 2 cases were ongoing when the patient completed the questionnaire. Only 1 patient with normal PCT had significant bleeding. A higher PCT was associated with more severe AS (p = 0.002, Table 1) and with the use of antiplatelet therapy (p = 0.043). Patients without antiplatelet therapy (n = 18) had a mean PCT of 126.5 (SD 36.94) vs patients on antiplatelet therapy, mean PCT of 174.5 (SD 82.15). There was no statistically significant relationship between PCT and vWF activity (p = 0.16).ConclusionThis study demonstrates that PCT is associated with AS severity but this association may be partly explained by an excess of antiplatelet therapy use in patients with severe AS. In this small sample there was no association between platelet closure time and abnormal vWF activity. Ongoing studies will explore these findings in greater detail.Abstract 216 Table 1Severity of ASMildModerateSevere Number of Patients8239Presence of Anaemia (% and range)25%(109–118 g/L)39.1%(90–126 g/L)33%(75–127 g/L)Platelet Closure Time in seconds(mean and SD)163.75SD 72.84109.5SD=25.13215.44SD 81.80Prolonged Closure Times (%)50%52.2%100%Antiplatelet Use in Patients with Prolonged CT (%)50%41.7%77.8%Abnormal vWF:CB assay (%)50%63.6%55.6%*Reference ranges: Normal Hb levels in women = 115–165 g/L and in men = 130–180 g/L. PFA closure times with collagen/ADP = 71–106 s</description><identifier>ISSN: 1355-6037</identifier><identifier>EISSN: 1468-201X</identifier><identifier>DOI: 10.1136/heartjnl-2016-309890.216</identifier><language>eng</language><publisher>London: BMJ Publishing Group LTD</publisher><ispartof>Heart (British Cardiac Society), 2016-06, Vol.102 (Suppl 6), p.A143</ispartof><rights>2016, Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions</rights><rights>Copyright: 2016 (c) 2016, Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions</rights><lds50>peer_reviewed</lds50><woscitedreferencessubscribed>false</woscitedreferencessubscribed></display><links><openurl>$$Topenurl_article</openurl><openurlfulltext>$$Topenurlfull_article</openurlfulltext><thumbnail>$$Tsyndetics_thumb_exl</thumbnail><linktopdf>$$Uhttps://heart.bmj.com/content/102/Suppl_6/A143.1.full.pdf$$EPDF$$P50$$Gbmj$$H</linktopdf><linktohtml>$$Uhttps://heart.bmj.com/content/102/Suppl_6/A143.1.full$$EHTML$$P50$$Gbmj$$H</linktohtml><link.rule.ids>114,115,314,776,780,23550,27901,27902,77343,77374</link.rule.ids></links><search><creatorcontrib>Choudhary, Ferrah</creatorcontrib><creatorcontrib>Kirby, Richard</creatorcontrib><creatorcontrib>Peter, Christina</creatorcontrib><creatorcontrib>Henderson, Robert</creatorcontrib><title>216 Does Aortic Stenosis Effect Platelet Closure Time and Von Willebrand Factor Activity?</title><title>Heart (British Cardiac Society)</title><description>BackgroundAbnormal platelet function is associated with increased bleeding risk. Limited evidence suggests that platelet dysfunction is a cause of bleeding in patients with aortic stenosis (AS).Method40 patients with degenerative AS underwent detailed haematological assessment. Platelet closure time (PCT) in seconds, was measured from a citrated blood sample by a PFA 100 benchtop analyser. In the presence of standardized flow conditions and collagen and ADP agonists, high shear rates are created, leading to aggregation of platelets and subsequent occlusion at the aperture site. The PCT is recorded as the time taken for the aperture occlusion to develop. Mean platelet volume (MPV) and platelet count (as per the impedance method) were measured from an EDTA sample by a XE2100 analyser. Von Willebrand factor activity was assessed with collagen binding assay (vWF:CB). Each patient completed a questionnaire to document use of antiplatelet therapy (with aspirin/clopidogrel) and bleeding events (using the ISTH bleeding questionnaire).ResultsOf the 40 patients, 8 had mild AS, 23 moderate AS and 9 severe AS. The average age was 74.9 years (range 39–97) and 47.5% were male. All patients had a normal MPV. A low platelet count was noted in 3 patients and all had an associated prolonged PCT. VWF activity was abnormal in 60% (n = 24: 5 mild AS, 12 moderate, 7 severe) but there was no correlation with AS severity.Overall, 25 patients (62.5%) had a prolonged PCT, including 5 patients (1 mild AS, 1 moderate AS and 3 severe AS) with significant bleeding events (2 patients with gastrointestinal bleeding and 3 with epistaxis). All bleeding events occurred within 3 months of the haematological assessment and in 2 cases were ongoing when the patient completed the questionnaire. Only 1 patient with normal PCT had significant bleeding. A higher PCT was associated with more severe AS (p = 0.002, Table 1) and with the use of antiplatelet therapy (p = 0.043). Patients without antiplatelet therapy (n = 18) had a mean PCT of 126.5 (SD 36.94) vs patients on antiplatelet therapy, mean PCT of 174.5 (SD 82.15). There was no statistically significant relationship between PCT and vWF activity (p = 0.16).ConclusionThis study demonstrates that PCT is associated with AS severity but this association may be partly explained by an excess of antiplatelet therapy use in patients with severe AS. In this small sample there was no association between platelet closure time and abnormal vWF activity. Ongoing studies will explore these findings in greater detail.Abstract 216 Table 1Severity of ASMildModerateSevere Number of Patients8239Presence of Anaemia (% and range)25%(109–118 g/L)39.1%(90–126 g/L)33%(75–127 g/L)Platelet Closure Time in seconds(mean and SD)163.75SD 72.84109.5SD=25.13215.44SD 81.80Prolonged Closure Times (%)50%52.2%100%Antiplatelet Use in Patients with Prolonged CT (%)50%41.7%77.8%Abnormal vWF:CB assay (%)50%63.6%55.6%*Reference ranges: Normal Hb levels in women = 115–165 g/L and in men = 130–180 g/L. PFA closure times with collagen/ADP = 71–106 s</description><issn>1355-6037</issn><issn>1468-201X</issn><fulltext>true</fulltext><rsrctype>article</rsrctype><creationdate>2016</creationdate><recordtype>article</recordtype><recordid>eNo1kE1LAzEQhoMoWKv_IeB5az5283GSUlsVCgoWFTyEJJtilu2mJqnQmxf_qL_EXaqnmXnnYQYeACBGE4wpu3p3OuamawuCMCsokkKiCcHsCIxwycQQvx73Pa2qgiHKT8FZSg1CqJSCjcBbj_58fd8El-A0xOwtfMquC8knOF-vnc3wsdXZtS7DWRvSLjq48hsHdVfD59DBF9-2zsRhXGibQ4RTm_2nz_vrc3Cy1m1yF391DFaL-Wp2Vywfbu9n02VhOBFFTYytCJOS14YYR6iwFeaWE0s1NkxXCFWc4LpfSM2rEpWCUFlaLBzmmFI6BpeHs9sYPnYuZdWEXez6jwpzSXlJEBM9RQ-U2TRqG_1Gx73CSA0S1b9ENUhUB4mqN0N_AY7nZi4</recordid><startdate>201606</startdate><enddate>201606</enddate><creator>Choudhary, Ferrah</creator><creator>Kirby, Richard</creator><creator>Peter, Christina</creator><creator>Henderson, Robert</creator><general>BMJ Publishing Group LTD</general><scope>K9.</scope></search><sort><creationdate>201606</creationdate><title>216 Does Aortic Stenosis Effect Platelet Closure Time and Von Willebrand Factor Activity?</title><author>Choudhary, Ferrah ; Kirby, Richard ; Peter, Christina ; Henderson, Robert</author></sort><facets><frbrtype>5</frbrtype><frbrgroupid>cdi_FETCH-LOGICAL-b728-d2bc526997db2be238c517c72c3a1b6a5005721d2389a7540482394c18e171333</frbrgroupid><rsrctype>articles</rsrctype><prefilter>articles</prefilter><language>eng</language><creationdate>2016</creationdate><toplevel>peer_reviewed</toplevel><toplevel>online_resources</toplevel><creatorcontrib>Choudhary, Ferrah</creatorcontrib><creatorcontrib>Kirby, Richard</creatorcontrib><creatorcontrib>Peter, Christina</creatorcontrib><creatorcontrib>Henderson, Robert</creatorcontrib><collection>ProQuest Health &amp; Medical Complete (Alumni)</collection><jtitle>Heart (British Cardiac Society)</jtitle></facets><delivery><delcategory>Remote Search Resource</delcategory><fulltext>fulltext</fulltext></delivery><addata><au>Choudhary, Ferrah</au><au>Kirby, Richard</au><au>Peter, Christina</au><au>Henderson, Robert</au><format>journal</format><genre>article</genre><ristype>JOUR</ristype><atitle>216 Does Aortic Stenosis Effect Platelet Closure Time and Von Willebrand Factor Activity?</atitle><jtitle>Heart (British Cardiac Society)</jtitle><date>2016-06</date><risdate>2016</risdate><volume>102</volume><issue>Suppl 6</issue><spage>A143</spage><pages>A143-</pages><issn>1355-6037</issn><eissn>1468-201X</eissn><abstract>BackgroundAbnormal platelet function is associated with increased bleeding risk. Limited evidence suggests that platelet dysfunction is a cause of bleeding in patients with aortic stenosis (AS).Method40 patients with degenerative AS underwent detailed haematological assessment. Platelet closure time (PCT) in seconds, was measured from a citrated blood sample by a PFA 100 benchtop analyser. In the presence of standardized flow conditions and collagen and ADP agonists, high shear rates are created, leading to aggregation of platelets and subsequent occlusion at the aperture site. The PCT is recorded as the time taken for the aperture occlusion to develop. Mean platelet volume (MPV) and platelet count (as per the impedance method) were measured from an EDTA sample by a XE2100 analyser. Von Willebrand factor activity was assessed with collagen binding assay (vWF:CB). Each patient completed a questionnaire to document use of antiplatelet therapy (with aspirin/clopidogrel) and bleeding events (using the ISTH bleeding questionnaire).ResultsOf the 40 patients, 8 had mild AS, 23 moderate AS and 9 severe AS. The average age was 74.9 years (range 39–97) and 47.5% were male. All patients had a normal MPV. A low platelet count was noted in 3 patients and all had an associated prolonged PCT. VWF activity was abnormal in 60% (n = 24: 5 mild AS, 12 moderate, 7 severe) but there was no correlation with AS severity.Overall, 25 patients (62.5%) had a prolonged PCT, including 5 patients (1 mild AS, 1 moderate AS and 3 severe AS) with significant bleeding events (2 patients with gastrointestinal bleeding and 3 with epistaxis). All bleeding events occurred within 3 months of the haematological assessment and in 2 cases were ongoing when the patient completed the questionnaire. Only 1 patient with normal PCT had significant bleeding. A higher PCT was associated with more severe AS (p = 0.002, Table 1) and with the use of antiplatelet therapy (p = 0.043). Patients without antiplatelet therapy (n = 18) had a mean PCT of 126.5 (SD 36.94) vs patients on antiplatelet therapy, mean PCT of 174.5 (SD 82.15). There was no statistically significant relationship between PCT and vWF activity (p = 0.16).ConclusionThis study demonstrates that PCT is associated with AS severity but this association may be partly explained by an excess of antiplatelet therapy use in patients with severe AS. In this small sample there was no association between platelet closure time and abnormal vWF activity. Ongoing studies will explore these findings in greater detail.Abstract 216 Table 1Severity of ASMildModerateSevere Number of Patients8239Presence of Anaemia (% and range)25%(109–118 g/L)39.1%(90–126 g/L)33%(75–127 g/L)Platelet Closure Time in seconds(mean and SD)163.75SD 72.84109.5SD=25.13215.44SD 81.80Prolonged Closure Times (%)50%52.2%100%Antiplatelet Use in Patients with Prolonged CT (%)50%41.7%77.8%Abnormal vWF:CB assay (%)50%63.6%55.6%*Reference ranges: Normal Hb levels in women = 115–165 g/L and in men = 130–180 g/L. PFA closure times with collagen/ADP = 71–106 s</abstract><cop>London</cop><pub>BMJ Publishing Group LTD</pub><doi>10.1136/heartjnl-2016-309890.216</doi></addata></record>
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title 216 Does Aortic Stenosis Effect Platelet Closure Time and Von Willebrand Factor Activity?
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