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Sugraliyev AB. [Heparin-Induced Thrombocytopenia]. KARDIOLOGIIA 2024; 64:18-25. [PMID: 38841785 DOI: 10.18087/cardio.2024.5.n2186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Accepted: 10/28/2022] [Indexed: 06/07/2024]
Abstract
The extensive use of therapeutic doses of heparin to prevent thrombosis in critically ill patients with COVID-19 during the pandemic has led to an increased incidence of bleeding and heparin-induced thrombocytopenia (HIT). In addition, the introduction of the AstraZeneca and Johnson&Johnson vaccines against COVID-19 into clinical practice was associated with the development of a rare but very severe, adverse thrombotic complication, vaccine-induced immune thrombotic thrombocytopenia (VITT). Thrombotic complications of VITT turned out to be similar to HIT both clinically and pathophysiologically. HIT is a potentially fatal immune-mediated adverse drug response that results in emergence of antibodies that activate platelets in the presence of heparin. HIT is characterized by a high incidence of venous and arterial thromboses, often with fatal outcomes. Currently, there are clearly defined international guidelines for the diagnosis, treatment and prevention of HIT. In case of thrombotic complications, non-heparin anticoagulants should be used.
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Pong T, Cyr K, Aparicio-Valenzuela J, Carlton C, Lee AM. A Modified 4Ts Score for Heparin-Induced Thrombocytopenia in the Mechanical Circulatory Support Population. J Cardiothorac Vasc Anesth 2023; 37:2499-2507. [PMID: 37407329 DOI: 10.1053/j.jvca.2023.06.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 06/16/2023] [Accepted: 06/21/2023] [Indexed: 07/07/2023]
Abstract
OBJECTIVE To identify risk factors and develop a pretest scoring system to differentiate patients with heparin-induced thrombocytopenia (HIT) in the mechanical circulatory support (MCS) population. The authors present a modified "4TMCS" scoring system, which considers the "type of mechanical circulatory support" that may help identify patients at risk for developing postoperative HIT. DESIGN A retrospective cohort study. Patients who underwent cardiac surgery were categorized into 3 groups: (1) normal platelet count, (2) thrombocytopenia with a negative HIT test, and (3) thrombocytopenia with a positive HIT test. A comparison of diagnostic accuracy between the 4Ts and 4TMCS probability scores was performed. SETTING At a single adult tertiary-care center. PARTICIPANTS A total of 5,314 patients who underwent cardiac surgery between May 1, 2008 and December 31, 2016. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS In total, 125 out of 5,314 patients (2.4%) were diagnosed with HIT, of whom 75 out of 5,314 (1.4%) had clinical evidence of thrombosis. Overall, in-hospital mortality was 25.6%, 11.7%, and 1.5% in the HIT(+), HIT(-), and control groups, respectively (p < 0.001). Mechanical circulatory support was associated with a significantly increased risk for HIT, with an incidence of 5.9% in patients receiving MCS versus 1.9% in those without (p < 0.001). Area under the receiver operator curve (AUC) analysis demonstrated improved diagnostic accuracy of the 4TMCS score compared with the 4Ts (AUC = 0.83 v 0.77, p < 0.044). The 4TMCS score had higher sensitivity than the 4Ts, using the guideline-recommended score cutoff of ≥4 (95.2% v 85.7%). CONCLUSION Heparin-induced thrombocytopenia is associated with worse outcomes and increased morbidity and mortality in the MCS population. Awareness of patient risk factors and the application of a modified 4TMCS probability score may allow for more accurate screening and treatment of HIT in the MCS population.
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Affiliation(s)
- Terrence Pong
- Department of Cardiothoracic Surgery, School of Medicine, Stanford University, Stanford, Stanford, CA
| | - Kevin Cyr
- Department of Cardiothoracic Surgery, School of Medicine, Stanford University, Stanford, Stanford, CA
| | - Joy Aparicio-Valenzuela
- Department of Cardiothoracic Surgery, School of Medicine, Stanford University, Stanford, Stanford, CA
| | - Cody Carlton
- Department of Cardiothoracic Surgery, School of Medicine, Stanford University, Stanford, Stanford, CA
| | - Anson M Lee
- Department of Cardiothoracic Surgery, School of Medicine, Stanford University, Stanford, Stanford, CA.
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Aguiar de Sousa D, Romoli M, Sánchez Van Kammen M, Heldner MR, Zini A, Coutinho JM, Arnold M, Ferro JM. Cerebral Venous Thrombosis in Patients With Heparin-Induced Thrombocytopenia a Systematic Review. Stroke 2022; 53:1892-1903. [PMID: 35240862 DOI: 10.1161/strokeaha.121.036824] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND Cerebral venous thrombosis (CVT) has recently been reported as a common thrombotic manifestation in association with vaccine-induced thrombotic thrombocytopenia, a syndrome that mimics heparin-induced thrombocytopenia (HIT) and occurs after vaccination with adenovirus-based SARS-CoV-2 vaccines. We aimed to systematically review the incidence, clinical features, and prognosis of CVT occurring in patients with HIT. METHODS The study protocol was registered with PROSPERO (CRD42021249652). MEDLINE, EMBASE and Cochrane CENTRAL were searched up to June 1, 2021 for HIT case series including >20 patients, or any report of HIT-related CVT. Demographic, neuroradiological, clinical, and mortality data were retrieved. Meta-analysis of proportions with random-effect modeling was used to derive rate of CVT in HIT and in-hospital mortality. Pooled estimates were compared with those for CVT without HIT and HIT without CVT, to determine differences in mortality. RESULTS From 19073 results, we selected 23 case series of HIT (n=1220) and 27 cases of HIT-related CVT (n=27, 71% female). CVT developed in 1.6% of 1220 patients with HIT (95% CI,1.0%-2.5%, I2=0%). Hemorrhagic brain lesions occurred in 81.8% of cases of HIT-related CVT and other concomitant thrombosis affecting other vascular territory was reported in 47.8% of cases. In-hospital mortality was 33.3%. HIT-related CVT carried a 29% absolute increase in mortality rate compared with historical CVT controls (33.3% versus 4.3%, P<0.001) and a 17.4% excess mortality compared with HIT without CVT (33.3% versus 15.9%, P=0.046). CONCLUSIONS CVT is a rare thrombotic manifestation in patients with HIT. HIT-related CVT has higher rates of intracerebral hemorrhage and a higher mortality risk, when compared with CVT in historical controls. The recently reported high frequency of CVT in patients with vaccine-induced thrombotic thrombocytopenia was not observed in HIT, suggesting that additional pathophysiological mechanisms besides anti-platelet factor-4 antibodies might be involved in vaccine-induced thrombotic thrombocytopenia-related CVT.
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Affiliation(s)
- Diana Aguiar de Sousa
- Department of Neurology, Centro Hospitalar Universitário de Lisboa Norte - Hospital de Santa Maria, Lisbon, Portugal (D.A.d.S., J.M.F.).,Faculdade de Medicina, Universidade de Lisboa, Portugal (D.A.d.S., J.M.F.)
| | - Michele Romoli
- Neurology and Stroke Unit, "Maurizio Bufalini" Hospital, Cesena, Italy (M.R.).,Neurology Clinic, University of Perugia - S. Maria della Misericordia Hospital, Italy (M.R.)
| | - Mayte Sánchez Van Kammen
- Department of Neurology, Amsterdam University Medical Center, the Netherlands (M.S.V.K., J.M.C.)
| | - Mirjam R Heldner
- Department of Neurology, University hospital and University of Bern, Switzerland (M.R.H., M.A.)
| | - Andrea Zini
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Neurologia e Rete Stroke Metropolitana, Ospedale Maggiore, Bologna, Italy (A.Z.)
| | - Jonathan M Coutinho
- Department of Neurology, Amsterdam University Medical Center, the Netherlands (M.S.V.K., J.M.C.)
| | - Marcel Arnold
- Department of Neurology, University hospital and University of Bern, Switzerland (M.R.H., M.A.)
| | - José M Ferro
- Department of Neurology, Centro Hospitalar Universitário de Lisboa Norte - Hospital de Santa Maria, Lisbon, Portugal (D.A.d.S., J.M.F.).,Faculdade de Medicina, Universidade de Lisboa, Portugal (D.A.d.S., J.M.F.)
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Bashover EM, Stefaniuk CM, Harding CV, Maitta RW. Use of a whole-cell ELISA to detect additional antibodies in setting of suspected heparin-induced thrombocytopenia. Eur J Haematol 2019; 103:99-106. [PMID: 31107976 DOI: 10.1111/ejh.13263] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 05/17/2019] [Indexed: 01/13/2023]
Abstract
OBJECTIVES Type II heparin-induced thrombocytopenia (HIT) is mediated by formation of antibodies to platelet factor 4 (PF4)-heparin complexes. We evaluated anti-PF4-heparin-negative samples for the presence of additional anti-platelet and anti-red blood cell (RBC) antibodies using whole-cell platelet/ RBC ELISAs we developed. METHODS Seventy-three samples tested for anti-PF4-heparin by ELISA were included: 62 tested negative, 9 tested positive, and 2 had equivocal results. Plasma specimens from healthy donors were used as controls. RESULTS 100% (9/9) anti-PF4-positive samples had anti-platelet antibodies detected by whole-cell platelet ELISA. 42.2% (27/64) anti-PF4-heparin-negative samples were negative for anti-platelet and anti-RBC antibodies. 32.8% (21/64) negative samples showed reactivity to both platelets and RBC; 12.5% (8/64) negative samples were each reactive with either platelet or RBC ELISA, respectively. Additionally, two samples that tested equivocal by anti-PF4-heparin ELISA had antibodies to both platelets and RBC by whole-cell ELISA. CONCLUSIONS Our study suggests that patients with thrombocytopenia testing negative for anti-PF4-heparin may still harbor antibodies to platelets. However, additional research is needed to determine the significance of these antibodies. Nevertheless, these findings may encourage clinicians to further investigate patients with possible immune-mediated etiologies of thrombocytopenia and anemia.
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Affiliation(s)
- Eva M Bashover
- Department of Pathology, Case Western Reserve University School of Medicine, University Hospitals Cleveland Medical Center, Cleveland, Ohio
| | - Catherine M Stefaniuk
- Department of Pathology, Case Western Reserve University School of Medicine, University Hospitals Cleveland Medical Center, Cleveland, Ohio
| | - Clifford V Harding
- Department of Pathology, Case Western Reserve University School of Medicine, University Hospitals Cleveland Medical Center, Cleveland, Ohio
| | - Robert W Maitta
- Department of Pathology, Case Western Reserve University School of Medicine, University Hospitals Cleveland Medical Center, Cleveland, Ohio
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Nagler M, Bakchoul T. Clinical and laboratory tests for the diagnosis of heparin-induced thrombocytopenia. Thromb Haemost 2017; 116:823-834. [DOI: 10.1160/th16-03-0240] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Accepted: 08/16/2016] [Indexed: 12/27/2022]
Abstract
SummaryA rapid diagnostic work-up is required in patients with suspected heparin-induced thrombocytopenia (HIT). However, diagnosis of HIT is challenging due to a number of practical issues and methodological limitations. Many laboratory tests and a few clinical scoring systems are available but the individual characteristics and the diagnostic accuracy of these are hard to appraise. The 4Ts score is a well evaluated clinical assessment tool with the potential to rule out HIT in many patients. Still, it requires experience and is subject to a relevant inter-observer variability. Immunoassays such as enzyme-linked immunosorbent assays or recently developed rapid assays are able to exclude HIT in a number of patients. But, accuracy of immunoassays differs depending on type of assay, threshold, antibody specificity and even manufacturer. Due to a comparatively low positive predictive value, HIT cannot be confirmed by immunoassays alone. In addition, only some of them are immediately accessible, particularly in small laboratories. While functional assays such as the serotonin release assay (SRA) and the heparin-induced platelet activation assay (HIPA) are considered as gold standard for diagnosis of HIT, they require a highly specialised laboratory. In addition, some of them are not adequately evaluated. In clinical practice, we recommend an integrated diagnostic approach combining not only clinical assessment (the 4Ts score) but immunoassays and functional assays as well. We propose a clear diagnostic algorithm supporting clinical decision-making. Furthermore, we provide an overview of all current laboratory techniques for HIT and discuss diagnostic pathways and strategies to reduce diagnostic errors, and future perspectives.
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Wallis DE, Lewis BE, Messmore H, Wehrmacher WH. State-of-the-Art Review : Heparin-induced Thrombocytopenia and Thrombosis Syndrome. Clin Appl Thromb Hemost 2016. [DOI: 10.1177/107602969800400303] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- Diane E. Wallis
- Cardiovascular Institute and Section of Hematology, Department of Medicine, Loyola University Medical Center, Maywood, Illinois, and Hines Veterans Hospital, Hines, Illinois, U.S.A
| | - Bruce E. Lewis
- Cardiovascular Institute and Section of Hematology, Department of Medicine, Loyola University Medical Center, Maywood, Illinois, and Hines Veterans Hospital, Hines, Illinois, U.S.A
| | - Harry Messmore
- Cardiovascular Institute and Section of Hematology, Department of Medicine, Loyola University Medical Center, Maywood, Illinois, and Hines Veterans Hospital, Hines, Illinois, U.S.A
| | - William H. Wehrmacher
- Cardiovascular Institute and Section of Hematology, Department of Medicine, Loyola University Medical Center, Maywood, Illinois, and Hines Veterans Hospital, Hines, Illinois, U.S.A
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Diagnostic value of immunoassays for heparin-induced thrombocytopenia: a systematic review and meta-analysis. Blood 2015; 127:546-57. [PMID: 26518436 DOI: 10.1182/blood-2015-07-661215] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 10/27/2015] [Indexed: 01/20/2023] Open
Abstract
Immunoassays are essential in the workup of patients with suspected heparin-induced thrombocytopenia. However, the diagnostic accuracy is uncertain with regard to different classes of assays, antibody specificities, thresholds, test variations, and manufacturers. We aimed to assess diagnostic accuracy measures of available immunoassays and to explore sources of heterogeneity. We performed comprehensive literature searches and applied strict inclusion criteria. Finally, 49 publications comprising 128 test evaluations in 15 199 patients were included in the analysis. Methodological quality according to the revised tool for quality assessment of diagnostic accuracy studies was moderate. Diagnostic accuracy measures were calculated with the unified model (comprising a bivariate random-effects model and a hierarchical summary receiver operating characteristics model). Important differences were observed between classes of immunoassays, type of antibody specificity, thresholds, application of confirmation step, and manufacturers. Combination of high sensitivity (>95%) and high specificity (>90%) was found in 5 tests only: polyspecific enzyme-linked immunosorbent assay (ELISA) with intermediate threshold (Genetic Testing Institute, Asserachrom), particle gel immunoassay, lateral flow immunoassay, polyspecific chemiluminescent immunoassay (CLIA) with a high threshold, and immunoglobulin G (IgG)-specific CLIA with low threshold. Borderline results (sensitivity, 99.6%; specificity, 89.9%) were observed for IgG-specific Genetic Testing Institute-ELISA with low threshold. Diagnostic accuracy appears to be inadequate in tests with high thresholds (ELISA; IgG-specific CLIA), combination of IgG specificity and intermediate thresholds (ELISA, CLIA), high-dose heparin confirmation step (ELISA), and particle immunofiltration assay. When making treatment decisions, clinicians should be a aware of diagnostic characteristics of the tests used and it is recommended they estimate posttest probabilities according to likelihood ratios as well as pretest probabilities using clinical scoring tools.
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Fiorenza MA, Frazee EN, Personett HA, Dierkhising RA, Schramm GE. Assessment of a modified 4T scoring system for heparin-induced thrombocytopenia in critically ill patients. J Crit Care 2013; 29:426-31. [PMID: 24462656 DOI: 10.1016/j.jcrc.2013.12.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 12/13/2013] [Accepted: 12/22/2013] [Indexed: 10/25/2022]
Abstract
PURPOSE The purpose of the study is to determine if a modified 4T (m4T) scoring system, which omits clinical evaluation of other thrombocytopenic etiologies, is different from the 4T scoring system's probability to predict a positive heparin-induced thrombocytopenia (HIT) laboratory test in the intensive care unit. MATERIALS AND METHODS This is a single-centered retrospective analysis of critically ill adults who had an enzyme-linked immunosorbent assay antiplatelet factor 4 antibody (ELISA anti-PF4 Ab) ordered. Patients were identified as HIT positive (optical density, ≥0.40) or HIT negative (optical density, <0.40) based on the ELISA anti-PF4 Ab. Both 4T and m4T scores were calculated, and the diagnostic accuracy was compared using paired receiver operating characteristic curves. RESULTS A total of 1487 adult intensive care unit patients with an ELISA anti-PF4 Ab ordered between January 2007 and December 2009 were eligible for study enrollment. Application of exclusion criteria and random selection yielded a total of 232 patients included for analysis (58 HIT-positive and 174 HIT-negative patients). The area under the curve for the 4T and m4T scores were 0.683 (95% confidence interval, 0.604-0.762) and 0.680 (95% confidence interval, 0.600-0.759), respectively (P=.065). CONCLUSION This study does not show a difference in the probability of the m4T and 4T scoring systems to predict a positive ELISA anti-PF4 Ab test in the critically ill patient population. Further prospective studies are needed to validate the m4T scoring system.
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Affiliation(s)
| | | | | | - Ross A Dierkhising
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN
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9
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The identification and management of heparin-induced thrombocytopenia in the vascular patient. J Vasc Surg 2012; 55:562-70. [DOI: 10.1016/j.jvs.2011.10.082] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 09/28/2011] [Accepted: 10/02/2011] [Indexed: 11/22/2022]
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Affiliation(s)
- Elizabeth A Eklund
- Division of Hematology/Oncology, Department of Medicine, Feinberg School of Medicine of Northwestern University, Olsen 8524, 710 N Fairbanks Court, Chicago, IL 60611, USA.
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Walenga JM, Prechel M, Jeske WP, Hoppensteadt D, Maddineni J, Iqbal O, Messmore HL, Bakhos M. Rivaroxaban - an oral, direct Factor Xa inhibitor - has potential for the management of patients with heparin-induced thrombocytopenia. Br J Haematol 2008; 143:92-9. [DOI: 10.1111/j.1365-2141.2008.07300.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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12
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Hopkins CK, Goldfinger D. Platelet transfusions in heparin-induced thrombocytopenia: a report of four cases and review of the literature. Transfusion 2008; 48:2128-32. [PMID: 18657085 DOI: 10.1111/j.1537-2995.2008.01822.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Heparin-induced thrombocytopenia (HIT) is a complication of heparin therapy associated with thrombocytopenia and thrombosis. The diagnosis of HIT is based on clinical criteria and laboratory tests, including the serotonin release assay (SRA). Because HIT patients are thrombocytopenic, platelet (PLT) transfusions may be contemplated; however, many published reviews have concluded that PLT transfusions are contraindicated in HIT because they may precipitate thrombotic events. This study reports four patients with clinically suspected HIT who received PLT transfusions without complications, and the literature regarding this subject has been reviewed. STUDY DESIGN AND METHODS Patients with a SRA ordered for suspected HIT were retrospectively identified. Charts of patients with positive SRAs who received a PLT transfusion when HIT was clinically suspected were reviewed for evidence of PLT transfusion safety and efficacy. A comprehensive search of the published literature regarding PLT transfusions in patients with HIT was conducted. RESULTS A SRA was performed on 189 patients with suspected HIT. Thirteen patients tested positive and 4 of these received a PLT transfusion. No patient developed a thrombotic complication. All 4 patients had adequate posttransfusion PLT increments. Two of the 3 patients with active bleeding had cessation of bleeding after transfusion. Review of the literature revealed no case of a complication clearly attributable to PLT transfusion. CONCLUSION Four patients with clinically suspected HIT and a positive SRA were transfused PLTs both efficaciously and safely. These outcomes, combined with the results of the literature review, suggest that PLT transfusions should not be withheld when clinically indicated in patients with HIT.
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Affiliation(s)
- Courtney K Hopkins
- Department of Pathology and Laboratory Medicine, Division of Transfusion Medicine, David Geffen School of Medicine at University of California, Los Angeles, California, USA.
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Lee DH, Warkentin TE. Frequency of Heparin-Induced Thrombocytopenia. HEPARIN-INDUCED THROMBOCYTOPENIA 2007. [DOI: 10.3109/9781420045093.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Kottke-Marchant K, Bontempo FA. A positive in vitro assay is required to diagnose heparin-induced thrombocytopenia. Med Clin North Am 2003; 87:1215-24. [PMID: 14680302 DOI: 10.1016/s0025-7125(03)00108-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A 57-year-old woman is admitted for coronary artery bypass graft. She has had a recent coronary angiogram (with heparin exposure), which revealed high-grade stenoses of the left anterior descending coronary artery, right coronary artery, and left circumflex artery. The preoperative platelet count is 300,000/microL. Heparin is administered during cardiopulmonary bypass. The platelet count on postoperative day 1 is 160,000/microL and on postoperative day 6 is 60,000/microL. Heparin-induced thrombocytopenia (HIT) is suspected and HIT assays are ordered.
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Affiliation(s)
- Kandace Kottke-Marchant
- Section of Hemostasis and Thrombosis, Department of Clinical Pathology, The Cleveland Clinic Foundation, 9500 Euclid Avenue, L30, Cleveland, OH 44195, USA.
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15
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Leo A, Winteroll S. Laboratory diagnosis of heparin-induced thrombocytopenia and monitoring of alternative anticoagulants. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 2003; 10:731-40. [PMID: 12965896 PMCID: PMC193890 DOI: 10.1128/cdli.10.5.731-740.2003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Albrecht Leo
- Blood Bank, Institute for Immunology, University Medical Center, Heidelberg University, Heidelberg, Germany.
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16
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Nguyen TN, Gal P, Ransom JL, Carlos R. Lepirudin use in a neonate with heparin-induced thrombocytopenia. Ann Pharmacother 2003; 37:229-33. [PMID: 12549954 DOI: 10.1177/106002800303700214] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVE To describe a case of heparin-induced thrombocytopenia (HIT) in a premature infant and the doses of danaparoid and lepirudin needed to achieve appropriate therapeutic endpoints. CASE SUMMARY A 30-week gestational age infant was diagnosed with HIT with heparin antibodies. Danaparoid 2.0-2.4 units/kg/h achieved anti-Xa levels of 0.2-0.4 U/mL, but thrombocytopenia failed to resolve. Lepirudin was started in place of danaparoid. Lepirudin doses of 0.03-0.05 mg/kg/h achieved target activated partial thromboplastin time values of 1.5-2.0 times baseline. DISCUSSION Dosing information for danaparoid in neonates is limited, and information for lepirudin appears only in German literature at this time. HIT is well documented in newborns, and lepirudin use in these situations is likely to increase. This report provides some guidance for optimal dosing. It also provides some guidance for HIT evaluation in preterm infants, in whom blood volume for laboratory tests is a major issue. CONCLUSIONS HIT is an important and potentially fatal problem in neonates. Lepirudin may be the drug of choice, especially since danaparoid is now unavailable. Initial lepirudin dosing should not exceed 0.05 mg/kg/h.
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Affiliation(s)
- Thuy N Nguyen
- Neonatal Intensive Care, The Women's Hospital of Greensboro, Moses Cone Health System, Greensboro, NC 27401-1020, USA
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Abstract
Heparin-induced thrombocytopenia (HIT) is an important side effect of heparin therapy associated with significant morbidity and mortality if unrecognized. The platelet count typically falls below 150,000/ micro l 5-14 days after heparin is started. Thrombosis is the major clinical complication. The diagnosis is confirmed with a variety of functional and antigenic assays. Heparin binds to PF4, resulting in a conformational change in the molecule that exposes neo-epitopes that act as immunogens. Antibodies form against the heparin-PF4 complex, the major target antigen. The IgG-heparin-PF4 immune complex binds either via its Fab domain to the platelet surface or via its Fc domain to the FcgammaIIA receptor on the surface of the platelet, resulting in further platelet activation. Continued release of PF4 from activated platelets leads to increasing PF4-heparin complex formation, and a self-propagating cycle of platelet consumption and generation of procoagulant platelet-derived microparticles. Other procoagulant effects of the HIT antibody include endothelial cell damage, stimulation of platelet-leukocyte aggregates, and release of tissue factor from monocytes.
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Affiliation(s)
- Robert F Reilly
- Section of Nephrology, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
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18
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Harenberg J, Wang LC, Hoffmann U, Huhle G, Feuring M. Laboratory diagnosis of heparin-induced thrombocytopenia type II after clearance of platelet factor 4/heparin complex. THE JOURNAL OF LABORATORY AND CLINICAL MEDICINE 2001; 137:408-13. [PMID: 11385361 DOI: 10.1067/mlc.2001.115099] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Laboratory confirmation of heparin-induced thrombocytopenia (HIT) is limited by assay sensitivity. We investigated whether laboratory confirmation can be improved after antigen clearance by determining free antibody and combining the results of antigenic and biologic assays. Blood samples were collected over 5 to 6 weeks in 14 HIT patients. As an antigenic assay, the fluorescence-linked immunofiltration assay (FLIFA) was performed, and as a biologic assay, the carbon 14-labeled serotonin release assay was performed. At day 1 when heparin was stopped, 11 of 14 patients showed positive results in both assays; thus each assay had a sensitivity of 80%. The 3 patients with negative results seroconverted in one or both assays during the subsequent 7 days. Combining the positive results of the assays increased the sensitivity to 100% at day 7, regardless of whether the antigenic or the biologic assay was performed first. Both assays became negative in all patients within 5 to 6 weeks. The sensitivity of antigen and biologic assays in HIT patients increased to 100% after the time course of the heparin-induced antibody. We assume that in some HIT patients the free antibody can be detected after withdrawal of heparin and after clearance of the platelet-factor 4/heparin complex.
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Affiliation(s)
- J Harenberg
- Department of Medicine IV, University Hospital, Faculty of Clinical Medicine Mannheim of the Ruprecht-Karls University of Heidelberg, Germany
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McCrae KR, Bussel JB, Mannucci PM, Remuzzi G, Cines DB. Platelets: an update on diagnosis and management of thrombocytopenic disorders. HEMATOLOGY. AMERICAN SOCIETY OF HEMATOLOGY. EDUCATION PROGRAM 2001; 2001:282-305. [PMID: 11722989 DOI: 10.1182/asheducation-2001.1.282] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Thrombocytopenia in the pregnant patient may result from a number of causes, most of which involve either immune-mediated platelet destruction or platelet consumption. Many of these disorders share clinical and laboratory features, making accurate diagnosis difficult. Moreover, uterine evacuation is indicated in the therapy of some disorders, while in others alternative interventions may allow the pregnancy to be carried to term. These and other issues are discussed as part of a comprehensive review of the differential diagnosis and management of thrombocytopenia in pregnancy. The term "refractory ITP" is used with reference to two distinct groups of patients: 1) patients in whom the platelet count cannot be easily increased, including those who are poorly responsive to initial single agent treatment, and 2) those with persistent thrombocytopenia despite the use of conventional therapies. An approach to management of the former group will be presented, followed by a discussion of patients with chronic refractory ITP. The latter will include presentation of new data on the role of Helicobacter pylori in ITP and whether its treatment ameliorates thrombocytopenia, as well as the use of rituximab and other modalities. Thrombotic microangiopathies such as thrombotic thrombocytopenic purpura (TTP) are rare, but life threatening causes of thrombocytopenia. Ultra-large multimers of von Willebrand factor (vWF) aggregate platelets intravascularly, and congenital or immune-mediated deficiencies of a metalloprotease that cleaves these ultra-large multimers may cause TTP. However, little information exists concerning the behavior of this protease in other physiological and pathological conditions. Levels of this protease have now been measured in healthy individuals of different ages, full-term newborns, pregnant women and a patients with variety of pathologic conditions, and these data will be reviewed herein. Heparin-induced thrombocytopenia/thrombosis (HIT/T) remains the most common antibody-mediated, drug-induced thrombocytopenic disorder, and a leading cause of morbidity and mortality. Based on clinical correlations and murine models, there is increasing evidence that antibodies to complexes between platelet factor 4 (PF4) and heparin cause HIT/T, and the molecular composition of the relevant antigen has also become better defined. However, the introduction of sensitive ELISAs to measure anti-PF4/heparin antibodies has complicated diagnosis in some settings in which the incidence of such antibodies in unaffected patients exceeds the incidence of the disease. In addition, the FDA approval of Lepirudin and Argatroban has expanded the repertoire of agents available for therapy of HIT/T and may change the approach to management of asymptomatic patients with thrombocytopenia. However, the optimal use of these drugs in commonly encountered settings remains in evolution, and a need for alternative approaches to prevention and treatment is evident.
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Affiliation(s)
- K R McCrae
- Department of Hematology/Oncology, Case Western Reserve University, School of Medicine, Cleveland, OH 44107-4937, USA
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20
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Fabris F, Ahmad S, Cella G, Jeske WP, Walenga JM, Fareed J. Pathophysiology of heparin-induced thrombocytopenia. Clinical and diagnostic implications--a review. Arch Pathol Lab Med 2000; 124:1657-66. [PMID: 11079020 DOI: 10.5858/2000-124-1657-pohit] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE This review of heparin-induced thrombocytopenia (HIT), the most frequent and dangerous side effect of heparin exposure, covers the epidemiology, pathophysiology, clinical presentation, diagnosis, and treatment of this disease syndrome. DATA SOURCES AND STUDY SELECTION Current consensus of opinion is given based on literature reports, as well as new information where available. A comprehensive analysis of the reasons for discrepancies in incidence numbers is given. The currently known mechanism is that HIT is mediated by an antibody to the complex of heparin->platelet factor 4, which binds to the Fc receptor on platelets. New evidence suggests a functional heterogeneity in the anti-heparin-platelet factor 4 antibodies generated to heparin, and a "superactive" heparin-platelet factor 4 antibody that does not require the presence of heparin to promote platelet activation or aggregation has been identified. Up-regulation of cell adhesion molecules and inflammatory markers, as well as preactivation of platelets/endothelial cells/leukocytes, are also considered to be related to the pathophysiology of HIT. Issues related to the specificity of currently available and new laboratory assays that support a clinical diagnosis are addressed in relation to the serotonin-release assay. Past experience with various anticoagulant treatments is reviewed with a focus on the recent successes of thrombin inhibitors and platelet GPIIb/IIIa inhibitors to combat the platelet activation and severe thrombotic episodes associated with HIT. CONCLUSIONS The pathophysiology of HIT is multifactorial. However, the primary factor in the mediation of the cellular activation is due to the generation of an antibody to the heparin-platelet factor 4 complex. This review is written as a reference for HIT research.
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Affiliation(s)
- F Fabris
- Department of Medical and Surgical Sciences, University of Padua, Medical School, Padua, Italy
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Abstract
Abstract
The frequency of immune heparin-induced thrombocytopenia (HIT) varies among prospective studies. It is unknown whether this is caused by differences in the heparin preparations, the patient populations, or the types of serologic assay used to confirm the diagnosis. Seven hundred forty-four patients were studied from 3 different clinical treatment settings, as follows: unfractionated heparin (UFH) during or after cardiac surgery (n = 100), UFH after orthopedic surgery (n = 205), and low-molecular-weight heparin (LMWH) after orthopedic surgery (n = 439). Both an activation assay and an antigen assay were used to detect heparin-dependent IgG (HIT-IgG) antibodies. By activation assay, the frequency of HIT-IgG formation ranged from a low of 3.2% in orthopedic patients receiving LMWH to a high of 20% in cardiac patients receiving UFH; by antigen assay, the corresponding frequencies ranged from 7.5% to 50%. Both UFH use (P = .002) and cardiac surgery (P = .01) were more likely to be associated with HIT-IgG formation. However, among patients in whom HIT-IgG formed and who were administered UFH, the probability for HIT was higher among orthopedic patients than among cardiac patients (by activation assay: 52.6% compared with 5%; odds ratio, 21.1 [95% CI, 2.2-962.8]; P = .001; by antigen assay: 34.5% compared with 2.0%; odds ratio, 25.8 [95% CI, 3.2-1141]; P < .001). It is concluded that there is an unexpected dissociation between the frequency of HIT-IgG formation and the risk for HIT that is dependent on the patient population. HIT-IgG antibodies are more likely to form in patients who undergo cardiac surgery than in orthopedic patients, but among patients in whom antibodies do form, orthopedic patients are more likely to develop HIT.
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Abstract
The frequency of immune heparin-induced thrombocytopenia (HIT) varies among prospective studies. It is unknown whether this is caused by differences in the heparin preparations, the patient populations, or the types of serologic assay used to confirm the diagnosis. Seven hundred forty-four patients were studied from 3 different clinical treatment settings, as follows: unfractionated heparin (UFH) during or after cardiac surgery (n = 100), UFH after orthopedic surgery (n = 205), and low-molecular-weight heparin (LMWH) after orthopedic surgery (n = 439). Both an activation assay and an antigen assay were used to detect heparin-dependent IgG (HIT-IgG) antibodies. By activation assay, the frequency of HIT-IgG formation ranged from a low of 3.2% in orthopedic patients receiving LMWH to a high of 20% in cardiac patients receiving UFH; by antigen assay, the corresponding frequencies ranged from 7.5% to 50%. Both UFH use (P = .002) and cardiac surgery (P = .01) were more likely to be associated with HIT-IgG formation. However, among patients in whom HIT-IgG formed and who were administered UFH, the probability for HIT was higher among orthopedic patients than among cardiac patients (by activation assay: 52.6% compared with 5%; odds ratio, 21.1 [95% CI, 2.2-962.8]; P = .001; by antigen assay: 34.5% compared with 2.0%; odds ratio, 25.8 [95% CI, 3.2-1141]; P < .001). It is concluded that there is an unexpected dissociation between the frequency of HIT-IgG formation and the risk for HIT that is dependent on the patient population. HIT-IgG antibodies are more likely to form in patients who undergo cardiac surgery than in orthopedic patients, but among patients in whom antibodies do form, orthopedic patients are more likely to develop HIT.
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Heparin-induced thrombocytopenia: new evidence for the dynamic binding of purified anti-PF4–heparin antibodies to platelets and the resultant platelet activation. Blood 2000. [DOI: 10.1182/blood.v96.1.182.013k18_182_187] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Immune heparin-induced thrombocytopenia (HIT) is associated with antibodies directed against a complex of platelet factor 4 (PF4) and heparin. We were able to affinity purify anti-PF4–heparin IgG (HIT IgG) from the plasma of 2 patients with HIT. Under conditions that were more physiological and sensitive than those in previous studies, we observed that this HIT IgG caused platelet aggregation on the addition of heparin. Platelets activated with HIT IgG increased their release and surface expression of PF4. We quantitated, for the first time, the binding of affinity-purified HIT iodine 125–IgG to platelets as they activated in a plasma milieu. Binding of the HIT IgG was dependent on heparin and required some degree of platelet activation. Blocking the platelet FcγRII with the monoclonal antibody IV.3 did not prevent HIT IgG binding to activated platelets. We concluded that anti-PF4–heparin IgG is the component in these HIT plasmas that induces platelet aggregation. The Fab region of HIT IgG binds to PF4–heparin on the surface of activated platelets. We propose that only then does the Fc portion of the bound IgG further activate the same or adjacent platelets through the Fc receptor. Our data support a dynamic model of platelet activation in which released PF4 enhances further antibody binding and more release.
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Heparin-induced thrombocytopenia: new evidence for the dynamic binding of purified anti-PF4–heparin antibodies to platelets and the resultant platelet activation. Blood 2000. [DOI: 10.1182/blood.v96.1.182] [Citation(s) in RCA: 139] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Immune heparin-induced thrombocytopenia (HIT) is associated with antibodies directed against a complex of platelet factor 4 (PF4) and heparin. We were able to affinity purify anti-PF4–heparin IgG (HIT IgG) from the plasma of 2 patients with HIT. Under conditions that were more physiological and sensitive than those in previous studies, we observed that this HIT IgG caused platelet aggregation on the addition of heparin. Platelets activated with HIT IgG increased their release and surface expression of PF4. We quantitated, for the first time, the binding of affinity-purified HIT iodine 125–IgG to platelets as they activated in a plasma milieu. Binding of the HIT IgG was dependent on heparin and required some degree of platelet activation. Blocking the platelet FcγRII with the monoclonal antibody IV.3 did not prevent HIT IgG binding to activated platelets. We concluded that anti-PF4–heparin IgG is the component in these HIT plasmas that induces platelet aggregation. The Fab region of HIT IgG binds to PF4–heparin on the surface of activated platelets. We propose that only then does the Fc portion of the bound IgG further activate the same or adjacent platelets through the Fc receptor. Our data support a dynamic model of platelet activation in which released PF4 enhances further antibody binding and more release.
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Schenk JF, Berg G, Mörsdorf S, Stefan B, Kroll H, Krischek B, Pindur G, Schieffer H, Wenzel E. Heparin-induced thrombocytopenia: a critical risk/benefit analysis of patients in intensive care treated with R-hirudin. Clin Appl Thromb Hemost 2000; 6:151-6. [PMID: 10898275 DOI: 10.1177/107602960000600306] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Patients in intensive care may be at high risk of in vivo platelet activation because comorbid conditions, such as infections, septicemia, shock, disseminated intravascular coagulation, and cancer represent procoagulant states. Hyperreactivity of platelets with or without a decline of cell count may result in thromboembolic complications potentially associated with the phenomenon of heparin-induced thrombocytopenia. We analyzed the data of 10 patients highly suspected of having heparin-induced thrombocytopenia during their intensive care treatment of 29 plus or minus 22 days. In seven patients, thrombocytopenia coincided with thromboembolic complications. Six patients had additionally undergone fibrinolytic therapy before starting activated partial thromboplastin time-adapted alternative anticoagulation with r-hirudin. In three patients, the platelet count decreased without a clinical manifestation, of heparin-induced thrombocytopenia. R-Hirudin treatment monitored by activated partial thromboplastin time and prothrombin time (PT) was effective and safe. The target value for activated partial thromboplastin time was a twofold prolongation. In four of five patients with deep venous thrombosis, a partial recanalization of the lower extremity could be achieved. Three patients with pulmonary embolism associated with deep venous thrombosis in two cases and in one additional case with an acute myocardial infarction did clinically profit from fibrinolysis with recombinant tissue plasminogen activator (rtPA) and r-hirudin treatment. Two lethal events probably caused by the underlying multimorbidity could not be prevented. No recurrence of thrombosis occurred, and there were no severe bleeding complications attributed to r-hirudin treatment. Platelet counts were significantly reduced on day 9.4 plus or minus 6.4 of heparin administration in all cases (>50% decrease related to the initial values) from 224,000 plus or minus 126,000/microL to 96,000 plus or minus 61,000/microL, and increased during rhirudin treatment to mean values of 224,000 plus or minus 126,000/microL. The heparin-induced platelet activation assay (HIPAA) assay was positive in 8/10 cases, whereas the PF4 enzyme-linked immunosorbent assay showed a positive result in four of eight analyzed cases. In four cases, the assays were concordantly positive. The PF4 enzyme-linked immunosorbent assay was not performed in two cases.
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Affiliation(s)
- J F Schenk
- Department of Clinical Hemostaseology and Transfusion Medicine, University of Homburg, Germany
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Koster A, Kuppe H, Crystal GJ, Mertzlufft F. Cardiovascular surgery without cardiopulmonary bypass in patients with heparin-induced thrombocytopenia type II using anticoagulation with recombinant hirudin. Anesth Analg 2000; 90:292-8. [PMID: 10648309 DOI: 10.1097/00000539-200002000-00010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- A Koster
- Department of Anesthesiology, German Heart Center, Berlin, Germany
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Cardiovascular Surgery Without Cardiopulmonary Bypass in Patients with Heparin-Induced Thrombocytopenia Type II Using Anticoagulation with Recombinant Hirudin. Anesth Analg 2000. [DOI: 10.1213/00000539-200002000-00010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Calaitges JG, Liem TK, Spadone D, Nichols WK, Silver D. The role of heparin-associated antiplatelet antibodies in the outcome of arterial reconstruction. J Vasc Surg 1999; 29:779-85; discussion 785-6. [PMID: 10231627 DOI: 10.1016/s0741-5214(99)70203-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
PURPOSE This study was designed to determine the incidence rate of heparin-associated antiplatelet antibodies (HAAb) in patients who require major vascular reconstruction and to determine whether the HAAb were associated with perioperative thrombotic events. METHODS One hundred six patients who underwent elective arterial reconstruction for cerebrovascular occlusive disease (n = 48), aortoiliac occlusive disease (n = 13), aortoiliac aneurysm (n = 17), mesenteric arterial occlusive disease (n = 1), or infrainguinal arterial occlusive disease (n = 28) prospectively underwent evaluation from July 1, 1996, to June 30, 1997. Heparin-associated antibody tests (with a two-point platelet aggregation assay) and platelet counts (via Coulter counter) were performed before surgery and on or after the 4th day after vascular reconstruction. Arterial reconstruction thromboses were established by means of duplex ultrasound scanning or angiography. Acute myocardial infarction (AMI) and venous thromboses were diagnosed with clinical criteria and duplex ultrasound scanning, respectively. A significant decrease in platelet count was defined as a platelet count of less than 100, 000/mm3 or as a more than 30% drop in the platelet count. RESULTS Twenty-two patients (21%) had at least one positive HAAb assay: one assay was positive before surgery only (after angiography), six were positive both before and after surgery, and 15 were positive after surgery only. There were three perioperative deaths-one in the HAAb-positive group and two in the HAAb-negative group. Ten thrombotic events occurred in the perioperative period. Four thrombotic events (three operative site thromboses and one AMI) occurred in the HAAb-positive group (18.2%). All of these patients were undergoing heparin therapy. Of the six patients (with three operative site thromboses, two deep venous thromboses, and one AMI) in the HAAb-negative group (7%; P =.21), three were undergoing heparin therapy. No patient who was HAAb positive with a thrombotic event had thrombocytopenia or a significant decrease in platelet count. CONCLUSION The frequent exposure to heparin by patients with peripheral vascular disease is associated with a high incidence rate (21%) of HAAb formation, which makes it one of the more common hypercoagulable conditions in these patients. The patients who were HAAb positive had a 2.6-fold increase in perioperative thrombotic events. Thrombocytopenia or decreasing platelet counts were not reliable clinical markers for identifying patients who were HAAb positive. It is suggested that all patients who have undergone heparin therapy and who have an unexplained perioperative thrombotic event develop should undergo testing for HAAb.
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Affiliation(s)
- J G Calaitges
- Department of Surgery, University of Missouri-Columbia, 65212, USA
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Abstract
Heparin-induced thrombocytopenia with or without thrombosis has been recognized increasingly as a serious complication of heparin use. This article reviews type II heparin-induced thrombocytopenia, which is mediated by an antibody that in most cases has specificity for a complex between heparin and platelet factor 4, a secreted platelet alpha-granule protein. The antibody-heparin-platelet factor 4 complex can activate platelets and endothelial cells, thereby initiating thrombosis. Clinical thrombosis in this syndrome may be arterial or venous. Treatment of the syndrome requires discontinuation of heparin and institution of an alternative anticoagulant.
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Affiliation(s)
- K L Kaplan
- University of Rochester Medical Center, Vascular Medicine Unit, NY 14642, USA.
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Affiliation(s)
- G Arepally
- UNM Health Sciences Center, Albuquerque, USA
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