doc28_35_2016-04-15 Michelson (Platelet Function Testing in the Clinic)
download 
Report Transcription
28_35_2016-04-15 Michelson (Platelet Function Testing in the Clinic)
Platelet Function Testing in the Clinic Alan D. Michelson Professor of Pediatrics and Professor of Medicine Harvard Medical School Director, Center for Platelet Research Studies Director, Thrombosis and Anticoagulation Program Boston Children’s Hospital, Dana-Farber Cancer Institute Disclosures Research grants: GLSynthesis, Lilly, Sysmex Data monitoring boards: Lilly Scientific advisory board: AstraZeneca Platelet Function • 3 Michelson Nature Reviews Drug Discovery 2010;9:154-169 Platelet Function Michelson Nature Reviews Drug Discovery 2010;9:154-169 Platelet Function Michelson Nature Reviews Drug Discovery 2010;9:154-169 Platelet Function Michelson Nature Reviews Drug Discovery 2010;9:154-169 Platelet Function Michelson Nature Reviews Drug Discovery 2010;9:154-169 Platelet Function Michelson Nature Reviews Drug Discovery 2010;9:154-169 Platelet Function Michelson Nature Reviews Drug Discovery 2010;9:154-169 Platelet Function Michelson Nature Reviews Drug Discovery 2010;9:154-169 Platelet Function Michelson Nature Reviews Drug Discovery 2010;9:154-169 Platelet Function Michelson Nature Reviews Drug Discovery 2010;9:154-169 Antiplatelet Agents FDA-approved Michelson Nature Reviews Drug Discovery 2010;9:154-169 Antiplatelet Agents FDA-approved Michelson Nature Reviews Drug Discovery 2010;9:154-169 Antiplatelet Agents FDA-approved Michelson Nature Reviews Drug Discovery 2010;9:154-169 Antiplatelet Agents FDA-approved Michelson Nature Reviews Drug Discovery 2010;9:154-169 Antiplatelet Agents FDA-approved Michelson Nature Reviews Drug Discovery 2010;9:154-169 Antiplatelet Agents FDA-approved Michelson Nature Reviews Drug Discovery 2010;9:154-169 Congenital Disorders of Platelet Function Michelson Nature Reviews Drug Discovery 2010;9:154-169 Congenital Disorders of Platelet Function Bernard-Soulier syndrome Platelet-type VWD GPVI defect α2β1 defect Receptors for Adhesive Proteins Glanzmann thrombasthenia Modified from Michelson Nature Reviews Drug Discovery 2010;9:154-169 Congenital Disorders of Platelet Function P2Y12 defect Receptors for Soluble Agonists TXA2 receptor defect Modified from Michelson Nature Reviews Drug Discovery 2010;9:154-169 Congenital Disorders of Platelet Function α-storage pool deficiency (gray platelet syndrome) α-Granules Quebec platelet disorder Paris-Trousseau syndrome/11-q terminal deletion disorder Modified from Michelson Nature Reviews Drug Discovery 2010;9:154-169 Congenital Disorders of Platelet Function δ-storage pool deficiency Hermansky-Pudlak syndrome Dense Granules Chediak-Higashi syndrome Modified from Michelson Nature Reviews Drug Discovery 2010;9:154-169 Congenital Disorders of Platelet Function α-Granules and Dense Granules α,δ-storage pool deficiency Modified from Michelson Nature Reviews Drug Discovery 2010;9:154-169 Congenital Disorders of Platelet Function Signal Transduction G proteins Phospholipase A2 Phospholipase C COX1 Modified from Michelson Nature Reviews Drug Discovery 2010;9:154-169 Congenital Disorders of Platelet Function Procoagulant Phospholipids Scott syndrome Stormorken Modified from Michelson Nature Reviews Drug Discovery 2010;9:154-169 Michelson in PLATELETS (Michelson, 3rd ed, Elsevier/Academic Press, 2013) Bernard-Soulier Syndrome Cattaneo in PLATELETS (Michelson, 3rd ed, Elsevier/Academic Press, 2013) MYH9-Related Disease Lambert & Poncz in PLATELETS (Michelson, 3rd ed, Elsevier/Academic Press, 2013) 2013;121:250 2013;121:250 Light Transmisssion Aggregometry Jennings in PLATELETS (Michelson, 2nd ed, Elsevier/Academic Press, 2007) Measurement of Platelet ATP Release by Lumiaggregometry PPi = inorganic pyrophosphate Hayward in PLATELETS (Michelson, 3rd ed, Elsevier/Academic Press, 2013) Lumiaggregometry PAR1 100 µM Dawood Blood 2012;120:5041 WHYHAVEGUIDELINESFORTHEDIAGNOSISOF INHERITEDPLATELETFUNCTIONDISORDERS(IPFD)? • Laboratorytestsforplateletfunctiondisordersarenotwell standardizedandnotaswidelyavailableasbloodclottingassays • Arationalstepwisediagnosticapproach,goingfromsimple screeningteststohighlyspecializedlaboratorytechniques,may becost-effective • Astepwisediagnosticapproachcanalsoallownon-specialized centerswithlimitedresourcestoformulatewell-grounded diagnostichypothesesforsubsequentreferraltospecialized centers • GeneticdiagnosisofIFPD,althoughdesirable,iscurrentlyusually impracticalbecausesinglecandidategenesforconventional sequencingseldomexistandnextgenerationsequencingisstill notwidelyavailable,isrelativelyexpensiveandispronetofalsepositives ISTH SSC Working Party JTH 2015;13:314 ISTH SSC Working Party JTH 2015;13:314 Bleeding ScoreQuestionnaire • Astandardizedbleedingtoolistobeencouragedto unifytheassessmentofbleedingseverity • ThequantitativeISTHVWDBleedingScorecanbe provisionallyused butitisnotvalidatedfor inheritedplateletdisorders ABleedingScoreQuestionaire shouldbespecifically validatedforIPFD ISTH SSC Working Party JTH 2015;13:314 Testsexcludedfromthediagnosticflowchart • PFA-100® and Template Skin Bleeding Time: not recommended because of their poor diagnostic accuracy and low sensitivity • Impedance aggregometry: not recommended because inaccurate for milder platelet defects (although it has theoretical advantages like rapidity, lack of centrifugation, ease of execution) • Mepacrine uptake by flow cytometry not recommended for the study of dense granules: lack of sensitivity/validation Theymaybeusedasadditionaltestsinindividual laboratoriesifadequatelystandardized ISTH SSC Working Party JTH 2015;13:314 DIAGNOSTICWORK-UP ISTH SSC Working Party JTH 2015;13:314 FIRSTSTEPTESTS LTA (screening) Bloodsmear (lumiaggregometry) Platelet size S N L normal altered All the remaining Morphologic alterations platelets GPS ARC othercells Stormorken CHS GATA1 GPS MYH9-RD BSS GPS GT-variant PT-VWD PTS VCF ARC GATA1 Filaminopathy Medich White MYH9-RD α δ GPS QPD WAS(±) ARC Stormorken GATA1 Scott WAS Flowcytometry(FC) (screening) Granulesrelease α,δ GPIIb/IIIaactivation δ- SPD HPS α-δ SPD CHS PSD WAS(±) FPDAMLMDS GT Stormorken Platelet GP GPIIb/IIIa GPIIIa GPIb/IX GPIb Filaminopathy (±) EPI(*) QPD/α 2 receptor(±)/GT/WAS(±)/FPD AML MDS/LADIII/δSPD/PSD/cPLA2/ARC(±)/White(±) ADP P2Y12 defect/GPS/GT/WAS(±)/FPD SPD/PSD/cPLA2/ARC(±) COLLAGEN α 2β 1/GPVI/SPD/P2Y12/GT/Stormorken/GPS/WAS/LADIII/PSD/c PLA2/ARC(±)/FPD AML MDS/GATA1/Filaminopathy(±) White(±) AA COX-1/TP defect/GT/P2Y12 MDS/ARC(±)/White(±) RISTOCETIN PT-VWD/BSS/GATA1 AML GT GT BSS/VC F BSS MDS/LADIII/δ- defect/δ-SPD/FPD AML Total amount of blood required: ~21-28ml ISTH SSC Working Party JTH 2015;13:314 DIAGNOSTICWORK-UP SECONDSTEPTESTS Flowcytometry (extension) LTA (extension) α-thr GPS/GT/LADIII TRAP-6 GPS/GT/LADIII U46619 TP defect/GT/LADIII GPIa/IIa α 2β 1 CRP GPVI/GT/LADIII GPIV GPIV CVX GPVI/GT/LADIII/ Filaminopathy(±) GPVI GPVI PAR4-ap GPS/GT/LADIII PMA PKC defect/GT/LADIII A23187 Ca2+ defects/GT/LADIII Inhibition byIloprost or PGE1 Serum TxB2 Gsplateletdefect cPLA2 COX-1 Txsynthase deficiency Granulescontent Platelet procoagulant activity PlateletGP impaired enhanced Scott Stormorken LTAristocetinenhanced A) Patient’splasma+control pltsenhanced B) Patient’splasma+control pltsnormal 2B-VWD GPS WAS(±) ARC Stormorken GATA1 Clot retraction Mixing tests (LTA/Flowcytometry) A α B PT-VWD δ α,δ δ- SPD HPS CHS WAS(±) FPDAMLMDS Filaminopathy(±) α-δ SPD TEM Granulecontent ormorphology Structural abnormalities GPS δ−SPD αδ-SPD PTS Medich ARC GT White α 2β 1 Stormorken York Medich WAS White PTS Filaminopathy Total amount of blood required: ~3-15ml ISTH SSC Working Party JTH 2015;13:314 DIAGNOSTICWORK-UP Biochemicalstudies THIRDSTEPTESTS Surfaceglycoproteins(WB) /Spreading assay/Adhesionandthrombusformationunder flow conditions/Protein phosphorylation (WB, FC)/Secondmessengers(Ca2+,IP3,cAMP)/ Receptorbindingstudies/WesternBlottingfor MYH10 Signallingpathwaydefects Filaminopathy(±) WAS Gsplateletdefect Receptordefects FPD/AML/MDS PTS MYH9-RD Total amount of blood required: ~3-50ml Molecular genetic diagnosis ITGA2B,ITGB3 GP1BA,GP1BB,GP9 GP1BA WAS NBEAL2,GFI1B Del11q23 (FLI1) del22q11.2 CD36 GP6 TMEM16F PLAU(duplication) TBXA2R HPS1,AP32B1,HPS3, HPS4,HPS5, HPS6,DTNBP1, BLOC1S3,PLDN LYST P2RY12 GNAS VPS33B,VIPAS39 STIM1,ORAI1 FERMT3 RUNX1 GATA1 FLNA TBXAS1 PLA2G4A MYH9 GT BSS PT-VWD WAS GPS PTS VCF GPIVdeficiency GPVIdeficiency ScottSyndrome QPD ThromboxaneA2 HPS CHS P2Y12defect Gsplateletdefect ARC Stormorken LADIII FPD/AML/MDS GATA1 Filaminopathy Txsynthasedeficiency cPLA2 MYH9-RD Association of Explanatory Variables Identified as Significant in Univariate Analysis with Bleeding Score After Adjustment for the Platelet Count These tests may be useful markers of future bleeding risk in ITP Frelinger Blood 2015;126:873 Platelet Function Testing for Monitoring of Antiplatelet Therapy? Laboratory tests to monitor P2Y12 inhibition Test Light transmission aggregation (LTA) of platelet-rich plasma Principle Decreased turbidity of aggregated vs. non-aggregated platelets Readout % aggregation VerifyNow P2Y12 Co-aggregation of fibrinogencoated beads with platelets in whole blood PRU (Platelet Reactivity Units) Multiplate MEA Whole blood impedance aggregometry AUC (area under the curve) PLT VASP/P2Y12 Changes in VASP phosphorylation measured by flow cytometry PRI (Platelet Reaction Index) TEG PlateletMapping(TM) Platelet-dependent increase in clot strength MA (Maximum Amplitude, mm) Published recommendations/guidelines 2011 ACCF/AHA/SCAI Guideline for Percutaneous Coronary Intervention (J Am Coll Cardiol 2011;58:e44– 122) Class IIb Platelet function testing may be considered in patients at high risk for poor clinical outcomes. (Level of Evidence: C) In patients treated with clopidogrel with high platelet reactivity, alternative agents, such as prasugrel or ticagrelor, might be considered. (Level of Evidence: C) Class III: No Benefit The routine clinical use of platelet function testing to screen patients treated with clopidogrel who are undergoing PCI is not recommended. (Level of Evidence: C) Platelet Function Testing for Monitoring of Antiplatelet Therapy? Not currently recommended in clinical practice, because randomized controlled trials of modification of antiplatelet therapy based on platelet function testing have not shown benefit: – GRAVITAS (Price JAMA 2011:305;1097) – TRIGGER-PCI (Trenk JACC 2012:59;2159) – ARCTIC (Collet NEJM 2012:367;2100) Barnard & Michelson N Engl J Med 1995;333:1051
