肝素诱导的血小板减少症 .ppt
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1、肝素诱导的血小板减少症肝素诱导的血小板减少症肝素诱导的血小板减少症肝素诱导的血小板减少症 史旭波史旭波 首都医科大学同仁医院首都医科大学同仁医院XIaXIIaIXaVIIa-III组织因子途径抑制物抗凝血酶IIa纤维蛋白原纤维蛋白蛋白C,蛋白S系统XaVIIIaVa内源性凝血系统外源性凝血系统凝血与抗凝系统凝血与抗凝系统EpidemiologyEpidemiologythe chance of significant exposure to heparin exceeds 50%in hospitalized patientsacute coronary syndrome (UA/MI)pul
2、monary embolismdeep venous thrombosis and prophylaxisatrial fibrillation/strokeheparinized pulmonary wedge cathetersPCIIABPSemi Thromb Hemost 1999;25 Suppl 1:57-60U.S.Estimated Causes of Accidental DeathsU.S.Estimated Causes of Accidental Deaths 1000 100040,00040,00090,00090,000Deaths per yearMedica
3、tion Errors Hospital AuditMedication Errors Hospital Audit%REFERENCE血小板减少症(血小板减少症(血小板减少症(血小板减少症(HIT/HITSHIT/HITSHIT/HITSHIT/HITS)美国每年有美国每年有1200万人因肢体或肺部血栓、心脏病或血管成万人因肢体或肺部血栓、心脏病或血管成型术而接受肝素治疗型术而接受肝素治疗36万人发生万人发生HIT12万人出现血栓并发症(静脉、动脉)万人出现血栓并发症(静脉、动脉)3.6万人死亡万人死亡 Heparin-induced ThrombocytopeniaHeparin-indu
4、ced ThrombocytopeniaHeparin-induced thrombocytopenia(HIT),an antibody-mediated syndrome,is associated with significant morbidity and mortalityconsidered a rarity in the pastunrecognized by many cliniciansdiagnoses can be difficult to confirmuntil recently there was no therapeutic options other than
5、discontinuation of heparinEpidemiologyEpidemiologythrombocytopenia is one of the most common laboratory abnormalities found among hospitalized patientsserologically proven HIT occurs in 1.5%to 3%of patients with heparin exposureN Engl J Med 1995;332:1330-5Cascade of events leading to formation of HI
6、T Cascade of events leading to formation of HIT antibodies and antibodies and prothromboticprothrombotic components Bleeding and ClottingBleeding and Clottingthe most feared consequence in these patients with a low platelet count is not bleeding but clottingpresent with mucocutaneous bleeding,rangin
7、g from petechiae and ecchymoses to life-threatening gastrointestinal and intracranial hemorrhageThrombosisThrombosisthrombosis is mostly venous not arterialmay result in bilateral deep venous thrombosis of the legspulmonary embolismvenous gangrene of fingers,toes,penis,or nipplesmyocardial infarctio
8、n,strokemesenteric arterial thrombosislimb ischemia and amputationCirculation 1999;100:587-93Am J Med 1996;101:502-7Thromb Haemost 1993;70:554-61Other Clinical FeaturesOther Clinical FeaturesSkin lesions at heparin injection siteSkin necrosisAcute platelet activation Acute inflammatory reactions(fev
9、er,chills,etc.)Skin NecrosisUsed with permission from Warkentin TE.Br J Haematol.1996;92:494497.Venous Limb Gangrene Used with permission from Warkentin TE,Elavathil LJ,Hayward CPM,Johnston MA,Russett JI,Kelton JG.Ann Intern Med.1997;127:804812.Morbidity and MortalityMorbidity and MortalityHIT-assoc
10、iated mortality is high(about 18%)5%of affected patients require limb amputationOvert bleeding or bruising is rare even with severe thrombocytopeniaAppropriate management can limit morbidity and mortalityHIT SyndromeHIT SyndromeType Inonimmunologic mechanisms(mild direct platelet activation by hepar
11、in)associated with an early(within 4 days)and usually mild decrease in platelet count(rarely 50%)count in the 50,000-80,000/mm range typical onset of 4-14 days occurs with any dose by any routepotential for development of life-threatening thromboembolic complicationsrarely causes bleedingRisks for H
12、ITRisks for HITType Iintravenous high-dose heparinType IIvaries with dose of heparinunfractionated heparin LMWHbovine porcinesurgical medical patientsDiagnosis of HITDiagnosis of HITabsence of another clear cause for thrombocytopeniathe timing of thrombocytopeniathe degree of thrombocytopeniaadverse
13、 clinical events(most often thrombocytpenia)positive laboratory tests for HIT antibodiesPathogenesis of Pathogenesis of Drug-induced thrombocytopeniaDrug-induced thrombocytopeniaCertain drugs(quinine,quinidine,sulfa antibiotics)link non-covalently to platelet membrane glycoproteinsvery rarely,IgG an
14、tibodies are produced that recognize these drug-glycoprotein complexesmacrophages remove the complexes causing severe thrombocytopeniaComparison of HIT and other Comparison of HIT and other Drug-Induced ThrombocytopeniaDrug-Induced Thrombocytopenia HIT Quinine/SulfaFrequency1/1001/10,000Onset5-8 day
15、s 7 daysPlatelet count20-150 x109/L50%that begins after 5 days of heparin therapy,but with the platelet count 150 x 109/L,should also raise the suspicion of HIT Common Laboratory Tests for HITCommon Laboratory Tests for HITTestAdvantagesDisadvantagesPAARapid and simple Low sensitivity-not suitable f
16、ortesting multiple samplesSRASensitivity 90%Washed platelet(technicallydemanding),needs radiolabeledmaterial 14CHIPARapid,sensitivity 90%Washed plateletsELISAHigh sensitivity,High cost,lower specificity for clinically significant HITThromb Haemost 1998;79:1-7platelet aggregation assay(PAA)serotonin
17、release assay(SRA)heparin induced platelet activation(HIPA)Functional AssayFunctional AssayPlatelet aggregation assay(PAA)performed by many laboratoriesincubate platelet-rich plasma from normal donors with patient plasma and heparinlimited by poor sensitivity and specificity because heparin can acti
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