Heparin induced thrombocytopenia hit is an antibodymediated adverse drug reaction that can lead to devastating thromboembolic complications, including pulmonary embolism, ischemic limb necrosis necessitating limb amputation, acute myocardial infarction, and stroke. Included patients being evaluated for thrombocytopenia or suspected hit in two clinical settings. Hit results from an interaction between negatively charged heparin and a. Smock, md associate professor of pathology, medical director, arup hemostasisthrombosis laboratory. Target population adult patients with suspicion or diagnosis of heparin induced thrombocytopenia key practice recommendations screening for hit 1. This reaction can destroy the patients platelets and, in the worst cases, cause clots to form in the patients blood, which is the opposite of what heparin is meant to achieve. Pdf heparininduced thrombocytopenia hit is a major health problem, especially in cardiac surgery theaters, cardiac catheterization labs. Heparininduced thrombocytopenia hit is an immunemediated, prothrombotic disorder caused by plateletactivating antibodies of igg class that recognize multimolecular complexes consisting of a.
Heparininduced thrombocytopenia hit is the development of thrombocytopenia a low platelet count, due to the administration of various forms of heparin, an anticoagulant. Negatively charged heparin forms a complex with positively charged platelet factor. Smock, md associate professor of pathology, medical director, arup hemostasisthrombosis laboratory, university of utah and george m. The 4ts scoring system is a screening tool that accurately rules out hit. Heparininduced thrombocytopenia new england journal. Heparininduced thrombocytopenia is a profoundly dangerous, potentially lethal, immunologically mediated adverse drug reaction to unfractionated heparin or, less commonly, to lowmolecular. Heparininduced thrombocytopenia hit is a lifethreatening. Heparin induced thrombocytopenia hit is a serious complication of heparin therapy that has a high rate of morbidity thrombosis and amputation and mortality. Treatment and prevention of heparininduced thrombocytopenia. The following guideline is intended to guide the management of heparin induced thrombocytopenia and includes recommendations for diagnosis and treatment agents. Has been described without heparin exposure associated with venous and arterial thrombosis typical previous infectious gram neg bacteria or inflammatory event pos immunoassay significant. This algorithm has been developed for md anderson using a multidisciplinary approach considering circumstances particular to md andersons specific patient population, services and structure, and clinical information. Hit is usually an immune response which typically occurs 410 days after exposure to heparin.
Heparininduced thrombocytopenia blood american society. Heparininduced thrombocytopenia hit is an antibodymediated adverse drug reaction that can lead to devastating thromboembolic complications, including pulmonary embolism, ischemic limb necrosis. Heparin induced thrombocytopenia hit is an immune igg mediated condition that occurs secondary to heparin exposure. Riia thrombocytopenia high risk of thrombosis occurs in 50% of untreated cases may be venous dvt, pe or arterial limb ischemia, stroke, mi thrombotic complications can be fatal. Heparininduced thrombocytopenia heparininduced thrombocytopenia hit is characterized by a decrease in the platelet count of more than 50% from the highest platelet count value after the start of heparin, an onset 5 to 10 days after the start of heparin, hypercoagulability, and the presence of heparindependent, plateletactivating igg. Heparin induced thrombocytopenia hit can cause an immunemediated thrombocytopenia that can lead to thrombosis, stroke, loss of limb, or other ischemic events e. Heparininduced thrombocytopenia hit is an adverse reaction to the drug heparin resulting in an abnormally low amount of platelets thrombocytopenia. This algorithm has been developed for md anderson using a multidisciplinary approach considering circumstances particular. Rodgers, md, phd professor of medicine and pathology, medical director, arup hemostasisthrombosis laboratory, university of utah. Hit predisposes to thrombosis the abnormal formation of blood clots inside a blood vessel because platelets release microparticles that activate thrombin, thereby. The primary clinical presentation of hit is thrombocytopenia, usually with a.
This cardiology patient page focuses on heparin induced thrombocytopenia hit, a complication of heparin therapy. Hit is caused by formation of immunoglobulin g antibodies that recognize complexes of platelet factor 4 pf4 and heparin and activate platelets resulting in mild to moderate thrombocytopenia platelet count thrombocytopenia is a serious condition in which patients have a low platelet count. Hit is a clinicopathologic diagnosis where laboratory testing plays an essential role. Laboratory testing reveals a platelet count of 86,000 per cubic millimeter, as compared with 225,000 per cubic millimeter at the time of discharge nine days earlier. Heparin induced thrombocytopenia hit is considered the most common form of drug induced thrombocytopenia as well as one of the common causes of thrombocytopenia in hospitalized patients.
Moser, md heparininduced thrombocytopenia hit is a complication seen in approximately 1%3% of patients treated with unfractionated heparin therapy. Heparininduced thrombocytopenia hit is a lifethreatening immune response to heparin and its derivatives that is associated with a high risk of thromboembolic complications. Physicians evidencebased clinical practice guidelines 8th edition. Heparininduced thrombocytopenia is a profoundly dangerous, potentially lethal, immunologically mediated adverse drug reaction to unfractionated heparin or, less commonly, to lowmolecular weight heparin. Heparin induced thrombocytopenia hit is a lifethreatening immune response to heparin and its derivatives that is associated with a high risk of thromboembolic complications. Heparininduced thrombocytopenia blood american society of. Heparin induced thrombocytopenia kettering health network.
Pathogenic antibodies to pf4heparin bind and activate cellular fc. If heparin is given after the procedure, monitor platelet count daily. Heparininduced thrombocytopenia symptoms, diagnosis and. Heparin induced thrombocytopenia hit is a complication of heparin therapy and is characterized by two types. May 03, 2012 heparin induced thrombocytopenia hit is an adverse reaction to the drug heparin resulting in an abnormally low amount of platelets thrombocytopenia. Heparininduced thrombocytopenia diagnosis and management theodore e. American society of hematology 2018 guidelines for management of venous.
Riia on platelets and monocytes to propagate a hypercoagulable state culminating in lifethreatening thrombosis. Heparininduced thrombocytopenia hit immune complexes heparinpf4igg cause platelet activation via the platelet fc. Heparin induced thrombocytopenia mild to moderate thrombocytopenia or a 50 percent reduction after exposure to heparin or lowmolecularweight heparin arterial and venous thrombosis. Hit may also be associated with low molecular weight heparin use.
Heparininduced thrombocytopenia hit is an immune complication of heparin therapy caused by antibodies to complexes of platelet factor 4 pf4 and heparin. However, not all thrombocytopenia is due to such system alterations. The most commonly used intravenous anticoagulant is heparin. Heparin induced thrombocytopenia hit is a known complication of heparin exposure. Heparininduced thrombocytopenia is a profoundly dangerous, potentially lethal, immunologically mediated adverse drug reaction to unfractionated heparin or, less commonly, to lowmolecular weight. Heparininduced thrombocytopenia thrombocytopenia aug 01, 2000 heparin induced thrombocytopenia hit is a wellknown complication of heparin therapy.
Heparininduced thrombocytopenia hit is an antibodymediated adverse drug reac tion that can lead to devastating thromboembolic complications, including pulmonary embolism, ischemic. Heparin induced thrombocytopenia hit is a lifethreatening complication of exposure to heparin ie, unfractionated heparin, low molecular weight lmw heparin that occurs in up to 5 percent of patients exposed, regardless of the dose, schedule, or route of administration. Heparininduced thrombocytopenia hit is a syndrome of platelet activation, thrombocytopenia, and thrombosis that occurs in 15% of patients who receive heparin. Heparin induced thrombocytopenia hit is an antibodymediated adverse drug reac tion that can lead to devastating thromboembolic complications, including pulmonary embolism, ischemic limb necrosis necessitating limb amputation, acute myocardial infarction, and stroke.
Heparininduced thrombocytopenia american society of hematology. Guidelines on the diagnosis and management of heparininduced thrombocytopenia. Guidelines from the american college of chest physicians accp28 recom mend platelet count monitoring in patients with a risk of hit that is. Heparin induced thrombocytopenia hit is the development of thrombocytopenia a low platelet count, due to the administration of various forms of heparin, an anticoagulant. Heparininduced thrombocytopenia hit can cause an immunemediated thrombocytopenia that can lead to thrombosis, stroke, loss of limb, or other ischemic events. The 4ts for the diagnosis of heparin induced thrombocytopenia hit is a tool developed to help clinicians rule out hit in patients who develop thrombocytopenia in the clinical setting. This is the case with heparin induced thrombocytopenia, or hit. Heparininduced thrombocytopenia hit is a lifethreatening complication of exposure to heparin ie, unfractionated heparin, low molecular weight lmw heparin that occurs in up to 5. This reaction can destroy the patients platelets and, in the worst cases, cause clots to form. A 63yearold man with coronary artery disease who has recently undergone bypass surgery presents with dyspnea. Heparininduced thrombocytopenia hit is one of the most common fatal.
Do not send hit antibody testing elisa or serotonin release assay sra 4. Two clinical forms of hit are generally recognized. Heparin induced thrombocytopenia hit treatment page 1 of 7. Heparininduced thrombocytopenia genetic and rare diseases. Pathogenic antibodies to pf4 heparin bind and activate cellular fc. Hit is a rare condition where a patient has a reaction to heparin. Some patients with hit develop serious thrombotic complications like limb. Solidphase enzymeimmunoassays are an objective tool for ruling out hit, but a positive test requires platelet activation tests such as the serotonin. This induces the formation of antipf4 heparin igg antibodies.
Hit occurs in up to 5% of patients receiving unfractionated heparin ufh for. Warkentin, md h eparin induced thrombocytopenia hit is an adverse drug reaction characterized by thrombocytopenia and. The 2012 accp clinical guidelines recommend treating hit and hitt with the nonheparin anticoagulant agents lepirudin, argatroban, and. Heparininduced thrombocytopenia hit is a complication of heparin therapy and is characterized by two types. American and british guidelines recommend therapeutic dose anticoagulation for 4 weeks in patients with isolated hit and 3 months for hit. Heparininduced thrombocytopenia thrombocytopenia induced thrombocytopenia heparin induced thrombocytopenia hit is characterized by a decrease in the platelet count of more than 50% from the highest platelet count valu. Hit typically presents with a fall in platelet count with or without venous andor arterial. This complication of heparin is often confusing because in hit, heparin does the opposite of what it is supposed to do. Heparin induced thrombocytopenia hit is an adverse prothrombotic disorder caused by an immune response to complexes of platelet factor 4 and polyanions. Heparin induced thrombocytopenia hit is a syndrome of platelet activation, thrombocytopenia, and thrombosis that occurs in 15% of patients who receive heparin. Heparin induced thrombocytopenia hit is an immunemediated, prothrombotic disorder caused by plateletactivating antibodies of igg class that recognize multimolecular complexes consisting of a positively charged chemokine, platelet factor 4 pf4, bound to negatively charged heparin or certain other plateletassociated. Heparininduced thrombocytopenia mild to moderate thrombocytopenia or a 50 percent reduction after exposure to heparin or lowmolecularweight heparin arterial and venous thrombosis. Heparin induced thrombocytopenia hit is an unusual immunemediated adverse drug reaction with the central paradox being its strong association with thrombosis, despite the role of an anticoagulant heparin in causing a fall in platelet count thrombocytopenia. Management of heparininduced thrombocytopenia uptodate.
Heparin induced thrombocytopenia adult inpatient clinical. This cardiology patient page focuses on heparininduced thrombocytopenia hit, a complication of heparin therapy. Diagnosis of heparininduced thrombocytopenia karen a. Moser, md heparininduced thrombocytopenia hit is a complication seen in approximately 1%3% of patients treated with unfractionated heparin.
Heparininduced thrombocytopenia hit is an adverse prothrombotic disorder caused by an immune response to complexes of platelet factor 4 and polyanions. This can occur due to certain disease processes such as alterations in the immune system or with leukemia. What diagnostic studies are warranted, and how should this patient be treated. Guidelines on the diagnosis and management of heparin. Heparininduced thrombocytopenia hit is an unusual immunemediated adverse drug reaction with the central paradox being its strong association with thrombosis, despite the role of an anticoagulant. Heparin induced thrombocytopenia hit treatment page 1 of 7 disclaimer. Hit is an antibodymediated disorder of coagulation caused by exposure to heparin and associated with significant risk of thromboembolic complications and death 1,2,3.
Heparininduced thrombocytopenia hit is considered the most common form of druginduced thrombocytopenia as well as one of the common causes of thrombocytopenia in hospitalized patients. Physicians evidencebased clinical practice guidelines. Key clinical pointsheparininduced thrombocytopenia heparininduced thrombocytopenia hit is characterized by a decrease in the platelet count of more than 50% from the highest platelet count valu. Because the platelet count normalizes even with continued heparin therapy, it is not associated with increased thrombotic risk. Negatively charged heparin forms a complex with positively charged platelet factor 4 pf4 1. Heparin induced thrombocytopenia hit is a clinicopathological syndrome that occurs when heparin dependent, igg antibodies bind to heparin platelet factor 4 pf4 complexes to activate platelets and produce a hypercoagulable state. Heparininduced thrombocytopenia hit is heparins most clinically. Warkentin, md h eparin induced thrombocytopenia hit is an adverse drug reaction characterized by thrombocytopenia and a high risk for venous or arterial thrombosis. Heparininduced thrombocyto penia hit is an adverse drug reaction characterized by thrombocytopenia and a high risk for venous or arterial thrombosis.
1545 491 1413 315 1314 685 172 707 597 1617 1132 799 314 973 1060 1356 1114 76 1431 1326 389 137 1417 283 488 701 985 986 992 1482 985 342 362 760 1350