Two clinical forms of hit are generally recognized. Heparin induced thrombocytopenia hit treatment page 1 of 7. A 63yearold man with coronary artery disease who has recently undergone bypass surgery presents with dyspnea. Heparininduced thrombocytopenia in a nonheparinnaive. Heparininduced thrombocytopenia hit with thrombosis occurs in about 1 in 2,000 heparintreated patients. A 52year old obese patient undergoing antithrombotic therapy with enoxaparin after hip surgery presented.
Heparininduced thrombocytopenia hit is an immunemediated complication of heparin therapy. It is associated with significant morbidity and mortality if unrecognized. List of heparininduced thrombocytopenia medications. Heparininduced thrombocytopenia is a clinicopathologic syndrome that can be associated with severe complications and significant mortality. Heparininduced thrombocytopenia hit is a complication of heparin therapy and is characterized by two types. The management of patients with heparininduced thrombocytopenia who require anticoagulant therapy kathryn hassell, md for patients with heparininduced thrombocytopenia hit, reexposure to heparin is generally not recommended. Heparininduced thrombocytopaenia following abdominal. Heparininduced thrombocytopenia is a prothrombotic disorder mediated by igg antibodies.
Heparininduced thrombocytopenia is a syndrome of antibodymediated thrombocytopenia that paradoxically is often associated with thrombosis. Heparin induced thrombocytopenia hit treatment page 2 of 7 disclaimer. Heparininduced thrombocytopenia associated with pulmonary. Coexistence of heparininduced thrombocytopenia and. Thrombotic thrombocytopenic purpura ou health sciences center. 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. However, these patients are likely to require anticoagulation therapy at some point in the future. Heparin induced thrombocytopaenia hit is a rare lifethreatening complication following exposure to heparin. Novel oral anticoagulants for heparininduced thrombocytopenia.
Temporal aspects of heparininduced thrombocytopenia nejm. Heparininduced thrombocytopenia history and exam bmj. Type ii heparininduced thrombocytopenia hit is a lifethreatening adverse drug reaction initiated by heparin administration. Patients receiving implantation of ventricular assist devices vad suffer a high incidence of heparin induced thrombocytopenia hit. Misdiagnosis of heparininduced thrombocytopenia hit is common and exposes patients to highrisk therapies and potentially serious adverse events. Evidencebased guidelines for managing patients with immune thrombocytopenia itp were last presented by ash. Heparininduced thrombocytopenia shaikh n j emerg trauma shock. Once hit is clinically suspected, heparin should be stopped immediately and direct thrombin inhibitor. Heparininduced thrombocytopenia hit is an immunemediated hypercoagulable disorder caused by antibodies to platelet factor 4 pf4 and heparin. Coexistence of heparininduced thrombocytopenia and thrombotic thrombocytopenic purpura in a postoperative cardiac surgery patient. Evaluation of pretest clinical score 4 ts for the diagnosis of heparininduced thrombocytopenia in two clinical settings.
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. Each category receives a score of 0 to 2, and the resulting total score places patients at. Target population adult patients with suspicion or diagnosis of heparin induced thrombocytopenia key practice recommendations screening for. The pathophysiology of heparininduced thrombocytopenia includes an immunemediated reaction to heparin that activates platelets and results in an acquired hypercoagulability. As compared with dtis, fondaparinux therapy is also more userfriendly intermittent subcutaneous injections. Heparininduced thrombocytopenia hit is an antibodymediated adverse drug reaction that can lead to devastating thromboembolic complications, including pulmonary embolism, ischemic limb necrosis. Heparininduced thrombocytopenia is the development of thrombocytopenia due to the administration of heparin. The widely used 4 ts clinical scoring system evaluates the following 4 criteria. Recognition, treatment, and prevention of heparininduced thrombocytopenia.
Clinical features of heparininduced thrombocytopenia including risk factors for thrombosis. Hit is the most common type of druginduced, immunemediated thrombocytopenia and is associated with high morbidity and mortality if undiagnosed the wide use of heparin in hospitalised patients demonstrates that hit can develop in patients receiving. Hit predisposes to thrombosis and, when identified, the condition is then called heparininduced thrombocytopenia and thrombosis hitt. It is mediated by immunemediated thrombocytopaenia due to antibody against heparin pl. An overview of the heparininduced thrombocytopenia syndrome. Downloaded from at univ of cincinnati serials dept on june 27, 2017. We described a rare case of lmwhinduced hit complicated with proven pulmonary embolism pe in a 75yearold male patient who hospitalized with diagnose of right knee osteoarthritis and was underwent total knee arthroplasty. Hit is usually an immune response which typically occurs 410 days after exposure to heparin. Thrombocytopenia tp is a common finding in patients hospitalized for cardiovascular causes and needing antiplatelet and anticoagulant therapies.
The arterial or venous thromboses may threaten life and limb hence alternative. Thrombocytopenia is no longer essential for the diagnosis of hit, since a 50% drop in the platelet count may be a more specific indicator. N engl j med dec at 23 years of followup, life expectancy was nearly 3 years longer with prostatectomy than with watchful waiting. Differential diagnosis of thrombocytopenia in the icu. Bleeding and coagulopathies in critical care inside the silver fridge.
Fondaparinux has often been used offlabel to treat hit type ii in patients without aki. Guidelines on the diagnosis and management of heparin. Loriann linkins from mcmaster university discusses her study of rivaroxaban in heparininduced thrombocytopeniahit. Complications of hit are venousarterial thrombosis, skin gangrene, and acute platelet activation syndrome. Nonheparin anticoagulants for heparininduced thrombocytopenia. Delayedonset heparininduced thrombocytopenia and thrombosis. Administration of low molecular weight heparin lmwh is recommended for prophylaxis of venous thromboembolism in patients undergoing hip surgery. Heparin induced thrombocytopenia nejm pdf antiplatelet factor 4 heparin antibodies present a major risk of heparin induced thrombocytopenia hit. Heparininduced thrombocytopenia pubmed central pmc. Heparin induced thrombocytopenia hit is a potentially devastating complication of therapy with either unfractionated or lowmolecularweight heparin. Heparin induced thrombocytopenia is a prothrombotic disorder caused by plateletactivating antibodies that recognize platelet factor 4 pf4 heparin complexes. Download heparin induced thrombocytopenia, fourth edition.
New guidelines for heparininduced thrombocytopenia on september 3, 20 uwmedicine laboratory services released a new reflexive panel for hit antibody testing. Hit develops in temporal association with heparin therapy and manifests either as an unexplained thrombocytopenia or thrombocytopenia complicated by thrombosis. Hit results from an autoantibody directed against platelet factor 4. New guidelines for heparininduced thrombocytopenia. Heparininduced thrombocytopenia investigations bmj. However, tp is not only a numeric parameter, but mostly a dynamic condition affected by the. Heparininduced thrombocytopenia hit is an adverse reaction to the drug heparin resulting in an abnormally low amount of platelets thrombocytopenia. The 4ts score is commonly used as it is the most evaluated tool to date.
Heparininduced thrombocytopenia hit is the most important and most frequent druginduced, immunemediated type of thrombocytopenia. University of nebraska medical center, department of internal medicine, division of hematology oncology, 987680 nebraska medical center, omaha, usa, ne. The current standard of care for preventing blood clots in a cancer setting includes treatment with lowmolecularweight heparin lmwh, but. Rivaroxaban in heparininduced thrombocytopenia youtube. Antiplatelet, thrombocytopenia, bleeding complications, thrombosis, anticoagulant agents. Stanley benke, department of internal medicine, division of hematologyoncology, winnipeg, manitoba, canada. 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 percent of patients exposed, regardless of the dose, schedule, or route of administration. The propensity for thrombosis distinguishes hit from other common druginduced. Heparininduced thrombocytopenia hit is an immunemediated syndrome of thrombocytopenia and thrombosis as a result of heparin exposure. New oral anticoagulants for the management of heparin. Heparin induced thrombocytopenia adult inpatient clinical. Anticoagulation in cancer patients with thrombocytopenia. Managing immune thrombocytopenia nejm journal watch. Heparininduced thrombocytopenia is a profoundly dangerous, potentially lethal, immunologically mediated adverse drug reaction to unfractionated heparin or, less commonly, to lowmolecular weight heparin.
Heparininduced thrombocytopenia, fourth edition download. New oral anticoagulants for the management of heparin induced thrombocytopenia. Antithrombotic therapy is required to manage heparin induced thrombocytopenia hitbut currently approved agents such as argatroban must be given parenterally and closely monitored. Laboratory testing reveals a platelet count of 86,000 per cubic millimeter, as. Because the platelet count normalizes even with continued heparin therapy, it is not associated with increased thrombotic risk. The primary objective of this study was to evaluate the impact of collaboration between an inpatient pharmacydriven anticoagulation management service ams and hospital reference laboratory to reduce inappropriate hit antibody.
A number of clinical prediction tools have been developed to help physicians determine clinical probability of hit. In this context, heparininduced thrombocytopenia hit type ii is a complication of rare incidence but sometimes fatal outcome. The following guideline is intended to guide the management of heparin induced thrombocytopenia and includes recommendations for diagnosis and treatment agents. Maximal treatment efficacy was obtained in all patients at an approximately sixfold less bleeding risk than in subjects treated with direct thrombin inhibitors dtis, including argatroban. Thrombosis precedes thrombocytopenia in approximately 25% of patients with hit. Antiplatelet and anticoagulation treatment in patients. The use of heparin to flush some vascular access devices makes hit a concern for infusion nurses. Heparininduced thrombocytopenia develops in a 57yearold man who underwent kneereplacement surgery 7 days previously.
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