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Gabarin N, Hack M, Revilla R, Arnold DM, Nazy I. Hematology in the post-COVID era: spotlight on vaccine-induced immune thrombotic thrombocytopenia and a conceptual framework (the 4P's) for anti-PF4 diseases. Expert Rev Hematol 2024; 17:39-45. [PMID: 38149432 DOI: 10.1080/17474086.2023.2298333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 12/19/2023] [Indexed: 12/28/2023]
Abstract
INTRODUCTION Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a life-threatening prothrombotic disorder first identified following the introduction of adenoviral vector vaccines for COVID-19. The condition is characterized by anti-PF4 antibodies and clinically presents with thrombocytopenia and thrombosis often in unusual anatomical sites. AREAS COVERED In this review, we discuss the clinical presentation, diagnostic testing, and treatment of VITT. We also review VITT-like syndromes that have been described in patients without previous vaccination. We propose a conceptual framework for the mechanism of anti-PF4 diseases that includes sufficiently high levels of PF4, the presence of a Polyanion that can form immune complexes with PF4, a Pro-inflammatory milieu, and an immunological Predisposition - the 4Ps. EXPERT OPINION Significant progress has been made in understanding the characteristics of the VITT antibody and in testing methods that can confirm that diagnosis. Future work should be directed at understanding long-term outcomes, mechanisms of thrombosis, and individual risk factors for this rare but dangerous immune-thrombotic disease.
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Affiliation(s)
- Nadia Gabarin
- Department of Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada
- McMaster Center for Transfusion Research, McMaster University, Hamilton, Ontario, Canada
| | - Michael Hack
- McMaster Center for Transfusion Research, McMaster University, Hamilton, Ontario, Canada
| | - Ryan Revilla
- McMaster Center for Transfusion Research, McMaster University, Hamilton, Ontario, Canada
| | - Donald M Arnold
- Department of Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada
- McMaster Center for Transfusion Research, McMaster University, Hamilton, Ontario, Canada
| | - Ishac Nazy
- Department of Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada
- McMaster Center for Transfusion Research, McMaster University, Hamilton, Ontario, Canada
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Gallo T, Curry SC, Heise CW, Antonescu CC, Raschke RA. Clinical decision support to reduce unnecessary diagnostic testing for heparin-induced thrombocytopenia. Br J Haematol 2023; 202:1011-1017. [PMID: 37271143 DOI: 10.1111/bjh.18902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 05/18/2023] [Accepted: 05/24/2023] [Indexed: 06/06/2023]
Abstract
Appropriate evaluation of heparin-induced thrombocytopenia (HIT) is imperative because of the potentially life-threatening complications. However, overtesting and overdiagnosis of HIT are common. Our goal was to evaluate the impact of clinical decision support (CDS) based on the HIT computerized-risk (HIT-CR) score, designed to reduce unnecessary diagnostic testing. This retrospective observational study evaluated CDS that presented a platelet count versus time graph and 4Ts score calculator to clinicians who initiated a HIT immunoassay order in patients with predicted low risk (HIT-CR score 0-2). The primary outcome was the proportion of immunoassay orders initiated but cancelled after firing of the CDS advisory. Chart reviews were conducted to assess anticoagulation usage, 4Ts scores and the proportion of patients who had HIT. In a 20-week period, 319 CDS advisories were presented to users who initiated potentially unnecessary HIT diagnostic testing. The diagnostic test order was discontinued in 80 (25%) patients. Heparin products were continued in 139 (44%) patients, and alternative anticoagulation was not given to 264 (83%). The negative predictive value of the advisory was 98.8% (95% CI: 97.2-99.5). HIT-CR score-based CDS can reduce unnecessary diagnostic testing for HIT in patients with a low pretest probability of HIT.
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Affiliation(s)
- Tyler Gallo
- Division of Clinical Data Analytics and Decision Support, University of Arizona College of Medicine - Phoenix, Phoenix, Arizona, USA
- Department of Pharmacy Practice and Science, University of Arizona College of Pharmacy, Phoenix, Arizona, USA
| | - Steven C Curry
- Division of Clinical Data Analytics and Decision Support, University of Arizona College of Medicine - Phoenix, Phoenix, Arizona, USA
- Department of Medical Toxicology, Banner - University Medical Center Phoenix, Phoenix, Arizona, USA
| | - C William Heise
- Division of Clinical Data Analytics and Decision Support, University of Arizona College of Medicine - Phoenix, Phoenix, Arizona, USA
- Department of Medical Toxicology, Banner - University Medical Center Phoenix, Phoenix, Arizona, USA
| | | | - Robert A Raschke
- Division of Clinical Data Analytics and Decision Support, University of Arizona College of Medicine - Phoenix, Phoenix, Arizona, USA
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Nilius H, Cuker A, Haug S, Nakas C, Studt JD, Tsakiris DA, Greinacher A, Mendez A, Schmidt A, Wuillemin WA, Gerber B, Kremer Hovinga JA, Vishnu P, Graf L, Kashev A, Sznitman R, Bakchoul T, Nagler M. A machine-learning model for reducing misdiagnosis in heparin-induced thrombocytopenia: A prospective, multicenter, observational study. EClinicalMedicine 2023; 55:101745. [PMID: 36457646 PMCID: PMC9706528 DOI: 10.1016/j.eclinm.2022.101745] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 10/26/2022] [Accepted: 10/27/2022] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Diagnosing heparin-induced thrombocytopenia (HIT) at the bedside remains challenging, exposing a significant number of patients at risk of delayed diagnosis or overtreatment. We hypothesized that machine-learning algorithms could be utilized to develop a more accurate and user-friendly diagnostic tool that integrates diverse clinical and laboratory information and accounts for complex interactions. METHODS We conducted a prospective cohort study including 1393 patients with suspected HIT between 2018 and 2021 from 10 study centers. Detailed clinical information and laboratory data were collected, and various immunoassays were conducted. The washed platelet heparin-induced platelet activation assay (HIPA) served as the reference standard. FINDINGS HIPA diagnosed HIT in 119 patients (prevalence 8.5%). The feature selection process in the training dataset (75% of patients) yielded the following predictor variables: (1) immunoassay test result, (2) platelet nadir, (3) unfractionated heparin use, (4) CRP, (5) timing of thrombocytopenia, and (6) other causes of thrombocytopenia. The best performing models were a support vector machine in case of the chemiluminescent immunoassay (CLIA) and the ELISA, as well as a gradient boosting machine in particle-gel immunoassay (PaGIA). In the validation dataset (25% of patients), the AUROC of all models was 0.99 (95% CI: 0.97, 1.00). Compared to the currently recommended diagnostic algorithm (4Ts score, immunoassay), the numbers of false-negative patients were reduced from 12 to 6 (-50.0%; ELISA), 9 to 3 (-66.7%, PaGIA) and 14 to 5 (-64.3%; CLIA). The numbers of false-positive individuals were reduced from 87 to 61 (-29.8%; ELISA), 200 to 63 (-68.5%; PaGIA) and increased from 50 to 63 (+29.0%) for the CLIA. INTERPRETATION Our user-friendly machine-learning algorithm for the diagnosis of HIT (https://toradi-hit.org) was substantially more accurate than the currently recommended diagnostic algorithm. It has the potential to reduce delayed diagnosis and overtreatment in clinical practice. Future studies shall validate this model in wider settings. FUNDING Swiss National Science Foundation (SNSF), and International Society on Thrombosis and Haemostasis (ISTH).
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Affiliation(s)
- Henning Nilius
- Department of Clinical Chemistry, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Adam Cuker
- Department of Medicine and Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Sigve Haug
- Mathematical Institute, University of Bern, Bern, Switzerland
- Albert Einstein Center for Fundamental Physics and Laboratory for High Energy Physics, University of Bern, Bern, Switzerland
| | - Christos Nakas
- Department of Clinical Chemistry, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Laboratory of Biometry, School of Agriculture, University of Thessaly, Volos, Greece
| | - Jan-Dirk Studt
- Division of Medical Oncology and Hematology, University and University Hospital Zurich, Zurich, Switzerland
| | | | - Andreas Greinacher
- Institut für Immunologie und Transfusionsmedizin, Universitätsmedizin Greifswald, Greifswald, Germany
| | - Adriana Mendez
- Department of Laboratory Medicine, Kantonsspital Aarau, Aarau, Switzerland
| | - Adrian Schmidt
- Clinic of Medical Oncology and Hematology, Municipal Hospital Zurich Triemli, Zurich, Switzerland
| | - Walter A. Wuillemin
- Division of Hematology and Central Hematology Laboratory, Cantonal Hospital of Lucerne and University of Bern, Switzerland
| | - Bernhard Gerber
- Clinic of Hematology, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland
| | - Johanna A. Kremer Hovinga
- Department of Hematology and Central Hematology Laboratory, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Prakash Vishnu
- Division of Hematology, CHI Franciscan Medical Group, Seattle, United States
| | - Lukas Graf
- Cantonal Hospital of St Gallen, Switzerland
| | | | - Raphael Sznitman
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - Tamam Bakchoul
- Centre for Clinical Transfusion Medicine, University Hospital of Tübingen, Tübingen, Germany
| | - Michael Nagler
- Department of Clinical Chemistry, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Corresponding author. Inselspital, Bern University Hospital, University of Bern, 3010 Bern, Switzerland.
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Cutler NS, Marchant BE. Comparison of screening scores for heparin induced thrombocytopenia after cardiopulmonary bypass. J Cardiothorac Vasc Anesth 2022; 36:3570-3575. [DOI: 10.1053/j.jvca.2022.04.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 03/21/2022] [Accepted: 04/06/2022] [Indexed: 11/11/2022]
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Besch G, Ilic D, Ginet M, d’Audigier C, Nguyen P, Ferreira D, Samain E, Mourey G, Pili-Floury S. Identification of Heparin-Induced Thrombocytopenia in Surgical Critically Ill Patients by Using the HIT Expert Probability Score: An Observational Pilot Study. J Clin Med 2022; 11:jcm11061515. [PMID: 35329842 PMCID: PMC8951334 DOI: 10.3390/jcm11061515] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 03/03/2022] [Accepted: 03/06/2022] [Indexed: 12/03/2022] Open
Abstract
Background: Heparin-induced thrombocytopenia (HIT) remains a challenging diagnosis especially in surgical intensive care unit (SICU) patients. The aim of the study was to evaluate for the first time the diagnostic accuracy of the HIT Expert Probability (HEP) score in the early identification of HIT in SICU patients. Methods: The HEP and 4Ts scores were calculated in all patients with suspected HIT during their stay in our SICU. The diagnosis of HIT was finally confirmed (HIT+ group) or excluded (HIT− group) by an independent committee blinded to the HEP and 4Ts score values. The primary outcome was the sensitivity and specificity of a HEP score ≥ 5 for the diagnosis of HIT. The secondary outcome was the area under the ROC curve (AUC) of the HEP and 4Ts scores in the diagnosis of HIT. Results: Respectively 6 and 113 patients were included in the HIT+ and HIT− groups. A HEP score value ≥ 5 had a sensitivity (95% confidence interval (95% CI)) of 1.00 (0.55−1.00), and a specificity (95% CI) of 0.92 (0.86−0.96). The AUC (95% CI) was significantly higher for the HEP score versus for the 4Ts score (0.967 (0.922−1.000) versus 0.707 (0.449−0.965); p = 0.035). Conclusions: A HEP score value < 5 could be helpful to rule out HIT in SICU patients.
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Affiliation(s)
- Guillaume Besch
- Department of Anesthesiology and Intensive Care Medicine, University Hospital of Besancon, F-25000 Besancon, France; (D.I.); (M.G.); (D.F.); (E.S.); (S.P.-F.)
- EA3920, University of Franche-Comte, 3 bvd Alexander Fleming, F-25000 Besancon, France
- Correspondence:
| | - Dejan Ilic
- Department of Anesthesiology and Intensive Care Medicine, University Hospital of Besancon, F-25000 Besancon, France; (D.I.); (M.G.); (D.F.); (E.S.); (S.P.-F.)
| | - Marc Ginet
- Department of Anesthesiology and Intensive Care Medicine, University Hospital of Besancon, F-25000 Besancon, France; (D.I.); (M.G.); (D.F.); (E.S.); (S.P.-F.)
| | - Clément d’Audigier
- Etablissement Français du Sang Bourgogne Franche-Comté, Hemostasis Department, Laboratoire de Biologie Médicale et de Greffe, F-25000 Besançon, France; (C.d.); (G.M.)
| | - Philippe Nguyen
- Department of Haematology, CHU Robert Debré, F-51000 Reims, France;
- EA3801, IFR-53, Reims Champagne-Ardenne University, F-51000 Reims, France
| | - David Ferreira
- Department of Anesthesiology and Intensive Care Medicine, University Hospital of Besancon, F-25000 Besancon, France; (D.I.); (M.G.); (D.F.); (E.S.); (S.P.-F.)
- EA481, Integrative and Clinical Neuroscience Laboratory, University Hospital of Besancon, F-25000 Besancon, France
| | - Emmanuel Samain
- Department of Anesthesiology and Intensive Care Medicine, University Hospital of Besancon, F-25000 Besancon, France; (D.I.); (M.G.); (D.F.); (E.S.); (S.P.-F.)
- EA3920, University of Franche-Comte, 3 bvd Alexander Fleming, F-25000 Besancon, France
| | - Guillaume Mourey
- Etablissement Français du Sang Bourgogne Franche-Comté, Hemostasis Department, Laboratoire de Biologie Médicale et de Greffe, F-25000 Besançon, France; (C.d.); (G.M.)
- Department of Clinical Hemostasis, University Hospital of Besancon, F-25000 Besancon, France
| | - Sebastien Pili-Floury
- Department of Anesthesiology and Intensive Care Medicine, University Hospital of Besancon, F-25000 Besancon, France; (D.I.); (M.G.); (D.F.); (E.S.); (S.P.-F.)
- EA3920, University of Franche-Comte, 3 bvd Alexander Fleming, F-25000 Besancon, France
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Abstract
Heparin-induced thrombocytopenia is a severe prothrombotic disease. Timely diagnosis and treatment are essential. Application of diagnostic algorithms based on validated clinical scoring tools and rapid, specific laboratory assays may improve outcomes.
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Stewart JJ, Turgeon R, Parker A, Koshman S, Omar MA. Comparison of risk-scoring systems for heparin-induced thrombocytopenia in cardiac surgery patients. Pharmacotherapy 2021; 41:1033-1040. [PMID: 34665467 DOI: 10.1002/phar.2636] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 09/16/2021] [Accepted: 10/05/2021] [Indexed: 11/11/2022]
Abstract
OBJECTIVES Several risk-scoring tools have been developed to exclude heparin-induced thrombocytopenia (HIT) in patients with thrombocytopenia, but these scores have not been reproduced or compared in the cardiac surgery population. The objective of this study was to validate and compare the modified 4T's (m4T) and Lillo-Le Louet (LLL) scores for HIT screening in the cardiac surgery population. METHODS In this nested case-control study, we retrospectively calculated the m4T and the cardiac surgery-specific score by LLL for 18 cases (HIT-positive) and 54 matched controls (HIT-negative) using characteristics known at the time the HIT assay was ordered post-cardiac surgery and compared their performances by their c-statistic (area under the receiver operating characteristic curve), sensitivity and specificity. RESULTS The median time from surgery to HIT assay order was 9.5 days (IQR 3.75-11.0) in the HIT-positive group and 2 days (IQR 2.0-3.0) in the HIT-negative group (p < 0.0001). The c-statistics for the m4T and the LLL scores were 0.76 (95% CI 0.64-0.85) and 0.63 (95% CI 0.51-0.74), respectively (p = 0.051). Sensitivity and specificity were 61% and 91% for the m4T, and 94% and 32% for the LLL score. CONCLUSION Performance of the m4T and LLL scores in discriminating HIT-positive from HIT-negative patients was modest among patients post-cardiac surgery. However, differences between the sensitivities of these scores suggest that the LLL score may be a safer tool for ruling out HIT in this population.
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Affiliation(s)
- Jackson J Stewart
- Pharmacy Services, Alberta Health Services, University of Alberta Hospital, Mazankowski Alberta Heart Institute, Edmonton, Alberta, Canada
| | - Ricky Turgeon
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Arabesque Parker
- Department of Critical Care, Division of Hematology Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Sheri Koshman
- Division of Cardiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Mohamed A Omar
- Pharmacy Services, Alberta Health Services, University of Alberta Hospital, Mazankowski Alberta Heart Institute, Edmonton, Alberta, Canada
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Ahmadinejad M, Shahbazi M, Chegini A. Heparin-Induced Thrombocytopenia in Iranian Cardiac Surgery Patients Using the 4Ts Clinical Scoring System and Laboratory Methods. Int J Hematol Oncol Stem Cell Res 2021; 15:230-238. [PMID: 35291665 PMCID: PMC8888360 DOI: 10.18502/ijhoscr.v15i4.7478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 09/11/2021] [Indexed: 11/29/2022] Open
Abstract
Background: Heparin-induced thrombocytopenia (HIT) is a serious adverse drug reaction. HIT diagnosis needs an algorithmic approach including clinical evaluation and laboratory tests (screening and confirmatory). Few studies have been conducted on HIT in Iran, and most existing research has been general and based on clinical evaluations alone. The present study was conducted to determine the prevalence of HIT among cardiac surgery patients using an algorithmic approach. Materials and Methods: A cross-sectional study was carried out over a period of 10 months, at Modares Hospital (Tehran, Iran) on 92 patients who were candidates for cardiac surgery. For the clinical evaluation, the 4Ts scoring system was used; in cases with 4Ts scores ≥4, a laboratory evaluation of anti-PF4/heparin antibody (Ab) was performed by enzyme-linked immunosorbent assay (ELISA) and a HIPA test too as a functional confirmatory method. The patients with 4Ts scores ≥4 who were ELISA positive (OD ≥0.2) and HIPA positive were taken as a definite case of HIT. Results: Of the 92 patients who had undergone cardiac surgery, 14 (15%) had 4Ts scores ≥4. Anti- PF4/heparin Ab was detected in eight patients using the ELISA and in six patients using the HIPA. Ultimately, definite HIT was confirmed in five of the patients. Conclusion: The prevalence of HIT was 5.4% among the cardiac surgery patients assessed in the present study. To the researchers’ knowledge, this is the first time that HIT has been evaluated in Iran using a comprehensive algorithmic approach including clinical history-taking and both immunological and functional laboratory tests, and the findings showed a slightly higher HIT frequency in this single-center study in comparison with the other studies carried out in other countries.
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Affiliation(s)
- Minoo Ahmadinejad
- Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran
| | - Massoumeh Shahbazi
- Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran
| | - Azita Chegini
- Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran
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Squiccimarro E, Jiritano F, Serraino GF, ten Cate H, Paparella D, Lorusso R. Quantitative and Qualitative Platelet Derangements in Cardiac Surgery and Extracorporeal Life Support. J Clin Med 2021; 10:jcm10040615. [PMID: 33561947 PMCID: PMC7914426 DOI: 10.3390/jcm10040615] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 01/30/2021] [Accepted: 02/03/2021] [Indexed: 01/19/2023] Open
Abstract
Thrombocytopenia and impaired platelet function are known as intrinsic drawbacks of cardiac surgery and extracorporeal life supports (ECLS). A number of different factors influence platelet count and function including the inflammatory response to a cardiopulmonary bypass (CPB) or to ECLS, hemodilution, hypothermia, mechanical damage and preoperative treatment with platelet-inhibiting agents. Moreover, although underestimated, heparin-induced thrombocytopenia is still a hiccup in the perioperative management of cardiac surgical and, above all, ECLS patients. Moreover, recent investigations have highlighted how platelet disorders also affect patients undergoing biological prosthesis implantation. Though many hypotheses have been suggested, the mechanism underlying thrombocytopenia and platelet disorders is still to be cleared. This narrative review aims to offer clinicians a summary of their major causes in the cardiac surgery setting.
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Affiliation(s)
- Enrico Squiccimarro
- Department of Cardiac Surgery, Mater Dei Hospital, 70125 Bari, Italy;
- Department of Emergency and Organ Transplant (DETO), University of Bari, 70125 Bari, Italy
- Cardio-Thoracic Surgery Department, Heart & Vascular Centre, Maastricht University Medical Centre (MUMC), 6229HX Maastricht, The Netherlands;
| | - Federica Jiritano
- Cardio-Thoracic Surgery Department, Heart & Vascular Centre, Maastricht University Medical Centre (MUMC), 6229HX Maastricht, The Netherlands;
- Cardiac Surgery Unit, Department of Experimental and Clinical Medicine, University “Magna Graecia” of Catanzaro, 88100 Catanzaro, Italy;
- Correspondence:
| | - Giuseppe Filiberto Serraino
- Cardiac Surgery Unit, Department of Experimental and Clinical Medicine, University “Magna Graecia” of Catanzaro, 88100 Catanzaro, Italy;
| | - Hugo ten Cate
- Center for Thrombosis and Hemostasis (CTH), University Medical Center of the Johannes Gutenberg-University Mainz, D-55131 Mainz, Germany;
- Thrombosis Center Maastricht, Maastricht University Medical Center (MUMC), 6229HX Maastricht, The Netherlands
- Cardiovascular Research Institute Maastricht (CARIM), 6229HX Maastricht, The Netherlands
| | - Domenico Paparella
- Division of Cardiac Surgery, Santa Maria Hospital, GVM Care & Research, 70125 Bari, Italy;
- Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy
| | - Roberto Lorusso
- Cardio-Thoracic Surgery Department, Heart & Vascular Centre, Maastricht University Medical Centre (MUMC), 6229HX Maastricht, The Netherlands;
- Cardiovascular Research Institute Maastricht (CARIM), 6229HX Maastricht, The Netherlands
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Moreno-Duarte I, Cooter M, Onwuemene OA, Ghadimi K, Welsby IJ. Clinical outcomes of cardiac surgery patients undergoing therapeutic plasma exchange for heparin-induced thrombocytopenia. Vox Sang 2021; 116:217-224. [PMID: 32965049 PMCID: PMC10308265 DOI: 10.1111/vox.13008] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 07/29/2020] [Accepted: 08/31/2020] [Indexed: 10/14/2023]
Abstract
BACKGROUND AND OBJECTIVES Heparin-induced thrombocytopenia (HIT) is an antibody-mediated condition that leads to thrombocytopenia and possible thrombosis. Patients with HIT who require cardiac surgery pose a challenge as high doses of heparin or heparin alternatives are required to permit cardiopulmonary bypass (CPB). Intraoperative therapeutic plasma exchange (TPE) is a valuable adjunct in the management of antibody-mediated syndromes including HIT. The clinical impact of TPE on thromboembolic events, bleeding and mortality after heparin re-exposure is not well established. We hypothesized that TPE with heparin re-exposure will not lead to HIT-related thromboembolic events, bleeding or increased mortality after cardiac surgery with CPB. MATERIALS AND METHODS We reviewed 330 patients who received perioperative TPE between September 2012 and September 2017. RESULTS Twenty four patients received TPE for HIT before anticipated heparin use for CPB. Most patients were males (79%) scheduled for advanced heart failure therapies. Three patients (12·5%) died within 30 days after surgery but none of the deaths were considered HIT-related. Thromboembolic events (TE) occurred in 3 patients within 7 days of surgery; of those, two were possibly HIT-related. CONCLUSION Therapeutic plasma exchange with heparin re-exposure was not strongly associated with HIT-related thrombosis/death after cardiac surgery with CPB.
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Affiliation(s)
| | - Mary Cooter
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA
| | - Oluwatoyosi A Onwuemene
- Division of Hematology, Department of Medicine, Duke University Medical Center, Durham, NC, USA
| | - Kamrouz Ghadimi
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA
| | - Ian J Welsby
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA
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Hilal T, Mudd J, DeLoughery TG. Hemostatic complications associated with ventricular assist devices. Res Pract Thromb Haemost 2019; 3:589-598. [PMID: 31624778 PMCID: PMC6781923 DOI: 10.1002/rth2.12226] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 05/08/2019] [Indexed: 01/03/2023] Open
Abstract
Hemostatic complications are common in patients with ventricular assist devices. The pathophysiologic mechanisms that lead to dysregulated hemostasis involve complex interactions between device surface, sheer stress, and blood flow. These factors lead to various manifestations that require a thorough understanding of the interplay among platelets, coagulation factors, and red cells. In this article, we review the pathophysiology of hematologic complications (bleeding, acquired von Willebrand disease, heparin-induced thrombocytopenia, hemolysis, stroke and pump thrombosis), the clinical manifestations, and the management of each. We summarize the evidence available for management of these entities and provide a pragmatic clinical review.
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Affiliation(s)
- Talal Hilal
- Division of Hematology/OncologyMayo Clinic Cancer CenterMayo ClinicPhoenixArizona
| | - James Mudd
- Center for Advanced Heart Disease and TransplantationProvidence Sacred Heart Medical CenterSpokaneWashington
| | - Thomas G. DeLoughery
- Division of Hematology/Medical OncologyKnight Cancer CenterOregon Health & Science UniversityPortlandOregon
- Division of Laboratory MedicineDepartment of PathologyOregon Health & Science UniversityPortlandOregon
- Division of Hematology/OncologyDepartment of PediatricsOregon Health & Science UniversityPortlandOregon
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Morita M, Nakanishi K, Masuda K, Yoshida K, Shimomura D, Ishida A, Shiga S, Ichiyama S. Acute non-heparin-induced thrombocytopenia during hemodiafiltration in a patient with multiple myeloma. Clin Case Rep 2019; 7:699-702. [PMID: 30997067 PMCID: PMC6452500 DOI: 10.1002/ccr3.1997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Revised: 11/19/2018] [Accepted: 12/04/2018] [Indexed: 11/13/2022] Open
Abstract
This report demonstrates that not only heparin-induced thrombocytopenia, but also hemodialysis conditions (platelet activation due to hemodiafiltration and heparin underdosing) may markedly reduce the platelet count and cause clotting in the hemodialysis circuit in patients in a hypercoagulable state. The clot prevention effects of bortezomib are therefore of great importance.
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Affiliation(s)
- Makiko Morita
- Department of Clinical LaboratoryKyoto University HospitalKyotoJapan
| | - Kayoko Nakanishi
- Department of Clinical LaboratoryKyoto University HospitalKyotoJapan
| | - Kenta Masuda
- Department of Clinical LaboratoryKyoto University HospitalKyotoJapan
| | | | | | - Atsumi Ishida
- Department of Clinical LaboratoryKyoto University HospitalKyotoJapan
| | - Shuichi Shiga
- Department of Clinical LaboratoryKyoto University HospitalKyotoJapan
| | - Satoshi Ichiyama
- Department of Clinical LaboratoryKyoto University HospitalKyotoJapan
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Lee CL, Colombo PC, Eisenberger A, Diuguid D, Jennings DL, Han J, Salna MP, Takeda K, Kurlansky PA, Yuzefpolskaya M, Garan AR, Naka Y, Takayama H. Abciximab/Heparin Therapy for Left Ventricular Assist Device Implantation in Patients With Heparin-Induced Thrombocytopenia. Ann Thorac Surg 2018; 105:122-128. [DOI: 10.1016/j.athoracsur.2017.06.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 04/21/2017] [Accepted: 06/07/2017] [Indexed: 12/13/2022]
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Wannamaker E, Kondo K, Johnson DT. Heparin-Induced Thrombocytopenia and Thrombosis: Preventing your Thrombolysis Practice from Taking a HITT. Semin Intervent Radiol 2017; 34:409-414. [PMID: 29249865 DOI: 10.1055/s-0037-1608864] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Heparin-induced thrombocytopenia and thrombosis (HITT) is an under-recognized cause of deep venous thrombosis treatment failure and of complications during catheter-directed thrombolysis. After a review of HITT pathophysiology, diagnosis, and management, three different cases are presented in this article. Each case highlights subtleties and challenges of HITT diagnosis and management. An example of a practical approach to the diagnosis of HITT is presented.
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Affiliation(s)
- Eric Wannamaker
- Department of Radiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Kimi Kondo
- Department of Radiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - D Thor Johnson
- Department of Radiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado
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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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Selleng S, Selleng K. Heparin-induced thrombocytopenia in cardiac surgery and critically ill patients. Thromb Haemost 2017; 116:843-851. [DOI: 10.1160/th16-03-0230] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 06/16/2016] [Indexed: 11/05/2022]
Abstract
SummaryThrombocytopenia as well as anti-platelet factor 4/heparin (PF4/H) antibodies are common in cardiac surgery patients and those treated in the intensive care unit. In contrast, heparin-induced thrombocytopenia (HIT) is uncommon in these populations (∼1 % and ∼0.5 %, respectively). A stepwise approach where testing for anti-PF4/H antibodies is performed only in patients with typical clinical symptoms of HIT improves diagnostic specificity of the laboratory assays without losing sensitivity, thereby helping to avoid overdiagnosis and resulting HIT overtreatment. Short-term re-exposure to heparin, especially given intraoperatively for cardiovascular surgery, is a reasonable therapeutic option in patients with a history of HIT who subsequently test negative for HIT antibodies. Organ failure(s), enhanced bleeding risks, and other characteristics require special considerations regarding non-heparin anticoagulation: Argatroban is the alternative anticoagulant with pharmacokinetics independent of renal function, but it has a prolonged half-life in case of impaired liver function. For bivalirudin, protocols during cardiopulmonary bypass surgery are established, and it is suitable for patients with liver insufficiency. A major issue of direct thrombin inhibitors are false high activated partial thromboplastin time values in patients with comorbidities affecting prothrombin, which can result in systematic underdosing of the drugs. This is not the case for danaparoid and fondaparinux, which can be monitored by anti-factor Xa assays, but have long half-lives and no suitable antidote. This review includes also information on management of on- and off-pump cardiac surgery, ventricular assist devices, percutaneous interventions, continuous renal replacement therapy, and extracorporeal membrane oxygenation in patients with HIT.
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Raschke RA, Gallo T, Curry SC, Whiting T, Padilla-Jones A, Warkentin TE, Puri A. Clinical effectiveness of a Bayesian algorithm for the diagnosis and management of heparin-induced thrombocytopenia. J Thromb Haemost 2017; 15:1640-1645. [PMID: 28622439 DOI: 10.1111/jth.13758] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Indexed: 11/28/2022]
Abstract
Essentials We previously published a diagnostic algorithm for heparin-induced thrombocytopenia (HIT). In this study, we validated the algorithm in an independent large healthcare system. The accuracy was 98%, sensitivity 82% and specificity 99%. The algorithm has potential to improve accuracy and efficiency in the diagnosis of HIT. SUMMARY Background Heparin-induced thrombocytopenia (HIT) is a life-threatening drug reaction caused by antiplatelet factor 4/heparin (anti-PF4/H) antibodies. Commercial tests to detect these antibodies have suboptimal operating characteristics. We previously developed a diagnostic algorithm for HIT that incorporated 'four Ts' (4Ts) scoring and a stratified interpretation of an anti-PF4/H enzyme-linked immunosorbent assay (ELISA) and yielded a discriminant accuracy of 0.97 (95% confidence interval [CI], 0.93-1.00). Objectives The purpose of this study was to validate the algorithm in an independent patient population and quantitate effects that algorithm adherence could have on clinical care. Methods A retrospective cohort comprised patients who had undergone anti-PF4/H ELISA and serotonin release assay (SRA) testing in our healthcare system from 2010 to 2014. We determined the algorithm recommendation for each patient, compared recommendations with the clinical care received, and enumerated consequences of discrepancies. Operating characteristics were calculated for algorithm recommendations using SRA as the reference standard. Results Analysis was performed on 181 patients, 10 of whom were ruled in for HIT. The algorithm accurately stratified 98% of patients (95% CI, 95-99%), ruling out HIT in 158, ruling in HIT in 10 and recommending an SRA in 13 patients. Algorithm adherence would have obviated 165 SRAs and prevented 30 courses of unnecessary antithrombotic therapy for HIT. Diagnostic sensitivity was 0.82 (95% CI, 0.48-0.98), specificity 0.99 (95% CI, 0.97-1.00), PPV 0.90 (95% CI, 0.56-0.99) and NPV 0.99 (95% CI, 0.96-1.00). Conclusions An algorithm incorporating 4Ts scoring and a stratified interpretation of the anti-PF4/H ELISA has good operating characteristics and the potential to improve management of suspected HIT patients.
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Affiliation(s)
- R A Raschke
- Division of Clinical Data Analytics and Decision Support, Department of Medicine, University of Arizona College of Medicine - Phoenix, Phoenix, AZ, USA
- Department of Critical Care Medicine, Banner - University Medical Center Phoenix, Phoenix, AZ, USA
| | - T Gallo
- Division of Clinical Data Analytics and Decision Support, Department of Medicine, University of Arizona College of Medicine - Phoenix, Phoenix, AZ, USA
| | - S C Curry
- Division of Clinical Data Analytics and Decision Support, Department of Medicine, University of Arizona College of Medicine - Phoenix, Phoenix, AZ, USA
- Department of Medical Toxicology, Banner - University Medical Center Phoenix, Phoenix, AZ, USA
| | - T Whiting
- Department of Critical Care Medicine, Banner - University Medical Center Phoenix, Phoenix, AZ, USA
| | - A Padilla-Jones
- Banner Research Institute, Banner - University Medical Center Phoenix, Phoenix, AZ, USA
| | - T E Warkentin
- Department of Pathology and Molecular Medicine, and Department of Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, ON, Canada
| | - A Puri
- Internal Medicine Residency, University of Arizona College of Medicine Phoenix, Phoenix, AZ, USA
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Minet V, Dogné JM, Mullier F. Functional Assays in the Diagnosis of Heparin-Induced Thrombocytopenia: A Review. Molecules 2017; 22:molecules22040617. [PMID: 28398258 PMCID: PMC6153750 DOI: 10.3390/molecules22040617] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 04/05/2017] [Accepted: 04/08/2017] [Indexed: 01/09/2023] Open
Abstract
A rapid and accurate diagnosis in patients with suspected heparin-induced thrombocytopenia (HIT) is essential for patient management but remains challenging. Current HIT diagnosis ideally relies on a combination of clinical information, immunoassay and functional assay results. Platelet activation assays or functional assays detect HIT antibodies that are more clinically significant. Several functional assays have been developed and evaluated in the literature. They differ in the activation endpoint studied; the technique or technology used; the platelet donor selection; the platelet suspension (washed platelets, platelet rich plasma or whole blood); the patient sample (serum or plasma); and the heparin used (type and concentrations). Inconsistencies in controls performed and associated results interpretation are common. Thresholds and performances are determined differently among papers. Functional assays suffer from interlaboratory variability. This lack of standardization limits the evaluation and the accessibility of functional assays in laboratories. In the present article, we review all the current activation endpoints, techniques and methodologies of functional assays developed for HIT diagnosis.
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Affiliation(s)
- Valentine Minet
- Department of Pharmacy, Namur Thrombosis and Hemostasis Center (NTHC), Namur Research Institute for LIfe Sciences (NARILIS), University of Namur, Namur 5000, Belgium.
| | - Jean-Michel Dogné
- Department of Pharmacy, Namur Thrombosis and Hemostasis Center (NTHC), Namur Research Institute for LIfe Sciences (NARILIS), University of Namur, Namur 5000, Belgium.
| | - François Mullier
- CHU UCL Namur, Namur Thrombosis and Hemostasis Center (NTHC), Hematology Laboratory, Université catholique de Louvain, Yvoir 5530, Belgium.
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Abstract
Heparin induced thrombocytopenia (HIT) is a pro-thrombotic and potentially fatal complication of heparin therapy. Its diagnosis rests on high clinical probability and the laboratory demonstration of anti-PF4/heparin antibodies. The high prevalence of thrombocytopenia in hospitalized patients and the high sensitivity but low specificity of immunoassays for HIT antibodies can lead to over-testing and over-diagnosis. We conducted a study to review HIT screening practices in a tertiary care setting. We reviewed 63 consecutive patients undergoing testing for anti-PF4/heparin antibodies over 3 months. Pre-test probability for HIT was calculated using the 4T score. Sixty three patients underwent testing for anti-PF4/heparin antibodies. Twenty one had been admitted for cardiovascular surgery, 5 for other surgery and 35 for non-surgical indications. Twenty nine patients (46 %) had low pre- test probability, twenty three (36.5 %) had intermediate probability, and eleven (17.4 %) had high pre-test probability of having HIT. Anti-PF4/heparin ELISA was positive in 8 of 63 patients. SRA was ordered for 16 patients and was positive in 5. Only five patients were diagnosed and treated for HIT. Over-testing for HIT is highly prevalent in a tertiary care setting. This increases cost and exposes patients to expensive anti-coagulation with its attendant risk of hemorrhage. The 4Ts score has been shown to have high sensitivity and may be used to rule out HIT in most situations, although its utility depends on subjective analysis. Consistently applying this in practice could minimize over-testing and facilitate safer, cost-effective care.
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Gupta S, Tiruvoipati R, Green C, Botha J, Tran H. Heparin induced thrombocytopenia in critically ill: Diagnostic dilemmas and management conundrums. World J Crit Care Med 2015; 4:202-212. [PMID: 26261772 PMCID: PMC4524817 DOI: 10.5492/wjccm.v4.i3.202] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 02/25/2015] [Accepted: 07/14/2015] [Indexed: 02/06/2023] Open
Abstract
Thrombocytopenia is often noted in critically ill patients. While there are many reasons for thrombocytopenia, the use of heparin and its derivatives is increasingly noted to be associated with thrombocytopenia. Heparin induced thrombocytopenia syndrome (HITS) is a distinct entity that is characterised by the occurrence of thrombocytopenia in conjunction with thrombotic manifestations after exposure to unfractionated heparin or low molecular weight heparin. HITS is an immunologic disorder mediated by antibodies to heparin-platelet factor 4 (PF4) complex. HITS is an uncommon cause of thrombocytopenia. Reported incidence of HITS in patients exposed to heparin varies from 0.2% to up to 5%. HITS is rare in ICU populations, with estimates varying from 0.39%-0.48%. It is a complex problem which may cause diagnostic dilemmas and management conundrum. The diagnosis of HITS centers around detection of antibodies against PF4-heparin complexes. Immunoassays performed by most pathology laboratories detect the presence of antibodies, but do not reveal whether the antibodies are pathological. Platelet activation assays demonstrate the presence of clinically relevant antibodies, but only a minority of laboratories conduct them. Several anticoagulants are used in management of HITS. In this review we discuss the incidence, pathogenesis, diagnosis and management of HITS.
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Nazi I, Arnold DM, Moore JC, Smith JW, Ivetic N, Horsewood P, Warkentin TE, Kelton JG. Pitfalls in the diagnosis of heparin-Induced thrombocytopenia: A 6-year experience from a reference laboratory. Am J Hematol 2015; 90:629-33. [PMID: 25809312 DOI: 10.1002/ajh.24025] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 03/03/2015] [Accepted: 03/21/2015] [Indexed: 12/11/2022]
Abstract
Heparin-induced thrombocytopenia (HIT) is caused by platelet-activating antibodies against complexes of platelet factor 4 (PF4) and heparin. The diagnosis of HIT is contingent on accurate and timely laboratory testing. Recently, alternative anticoagulants for the treatment of HIT have been introduced along with algorithms for better HIT diagnosis. However, the increased reliance on immunoassays for the diagnosis of HIT may have harmful consequences due to the high rate of false positive results. To compare trends and implications of current HIT testing approaches, we analyzed results over a six-year period from the McMaster University Platelet Immunology Reference Laboratory. From 2008 to 2013, 8,546 samples were investigated for HIT using both an in-house IgG-specific anti-PF4/heparin enzyme immunoassay (EIA) and the serotonin-release assay (SRA). Of 8,546 samples tested, 13.4% were true-positives (positive in both assays); 65.6% were true-negatives (negative in both assays); 20.9% were presumed false positive for HIT (EIA-positive/SRA-negative); and 0.2% were EIA-negative/SRA-positive. The frequency of EIA-positive/SRA-negative results increased over time (from 12.9% in 2008 to 22.9% in 2013). We found that the number of SRA-negative samples was reduced from referring centers that used an immunoassay as an initial screen; however, 41% of those samples tested negative in the immunoassay and in the SRA at the reference laboratory. The suspicion of HIT continues at a high rate and the agreement between the EIA and SRA test results remains problematic.
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Affiliation(s)
- Ishac Nazi
- Department of Medicine. Michael G. DeGroote School of Medicine; McMaster University; Hamilton Ontario Canada
| | - Donald M. Arnold
- Department of Medicine. Michael G. DeGroote School of Medicine; McMaster University; Hamilton Ontario Canada
- Canadian Blood Services; Hamilton Ontario Canada
| | - Jane C. Moore
- Department of Medicine. Michael G. DeGroote School of Medicine; McMaster University; Hamilton Ontario Canada
- Department of Pathology and Molecular Medicine; McMaster University; Hamilton Ontario Canada
| | - James W. Smith
- Department of Medicine. Michael G. DeGroote School of Medicine; McMaster University; Hamilton Ontario Canada
| | - Nikola Ivetic
- Department of Biochemistry and Biomedical Sciences; McMaster University; Hamilton Ontario Canada
| | - Peter Horsewood
- Department of Medicine. Michael G. DeGroote School of Medicine; McMaster University; Hamilton Ontario Canada
| | - Theodore E. Warkentin
- Department of Medicine. Michael G. DeGroote School of Medicine; McMaster University; Hamilton Ontario Canada
- Department of Pathology and Molecular Medicine; McMaster University; Hamilton Ontario Canada
| | - John G. Kelton
- Department of Medicine. Michael G. DeGroote School of Medicine; McMaster University; Hamilton Ontario Canada
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Chan CM, Woods CJ, Warkentin TE, Sheppard JAI, Shorr AF. The Role for Optical Density in Heparin-Induced Thrombocytopenia. Chest 2015; 148:55-61. [DOI: 10.1378/chest.14-1417] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
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Peripheral Thrombosis and Necrosis after Minimally Invasive Redo Mitral Valve Replacement due to Unknown Etiology: Difficult Diagnosis of Heparin Induced Thrombocytopenia. Case Rep Vasc Med 2015; 2015:383104. [PMID: 25954567 PMCID: PMC4411436 DOI: 10.1155/2015/383104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 04/01/2015] [Indexed: 12/04/2022] Open
Abstract
We report on a 75-year-old male with acute onset of peripheral thrombosis causing necrosis of the fingers, elbow, and toes associated with thrombocytopenia after minimally invasive redo mitral valve replacement. Both warfarin and dalteparin were commenced on postoperative day 1 and his INR reached 2.1 on postoperative day 4. On postoperative day 5, the patient developed peripheral thrombosis which progressed to necrosis on postoperative day 6. Platelet counts decreased significantly on the same day. His clinical features were compatible with heparin induced thrombocytopenia (HIT). However, serology testing was negative and the diagnosis was never confirmed. The patient was treated for HIT and platelet count improved eventually. Although no clear consensus exists, we believe this case illustrates why therapy for HIT should be initiated when clinical features strongly suggest HIT despite a negative serology test, unless an alternate diagnosis can be found.
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Pappalardo F, Agracheva N, Covello RD, Pieri M, De Bonis M, Calabrò MG, Koster A, Zangrillo A. Anticoagulation for Critically Ill Cardiac Surgery Patients: Is Primary Bivalirudin the Next Step? J Cardiothorac Vasc Anesth 2014; 28:1013-17. [DOI: 10.1053/j.jvca.2013.10.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Indexed: 11/11/2022]
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Sun X, Hill PC, Ellis J, Corso PJ, Taylor-Panek SL, Chen F. Ten-year screening for thrombocytopenia after aortic valve replacement. Interact Cardiovasc Thorac Surg 2014; 18:562-7. [DOI: 10.1093/icvts/ivt487] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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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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Matsumura Y, Nakada TA, Oda S. Relationship between the 4Ts scoring system and the antiplatelet factor 4/heparin antibodies test in critically ill patients. Acute Med Surg 2013; 1:37-44. [PMID: 29930820 DOI: 10.1002/ams2.15] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 11/10/2013] [Indexed: 01/06/2023] Open
Abstract
Aim Heparin-induced thrombocytopenia (HIT) is an adverse drug reaction and potentially progresses to fatal thrombosis. The 4Ts scoring system has been reported as a clinical pretest for HIT. However, its usefulness in critically ill patients has not yet been thoroughly examined. Thus, we evaluated the clinical usefulness of the 4Ts score in the diagnosis of HIT in critically ill patients. Methods One hundred and four critically ill patients who were admitted to our intensive care unit and who underwent the antiplatelet factor 4/heparin complex antibodies (PF4/heparin Ab) test with suspected HIT were enrolled in the study. The primary endpoint variable was the 4Ts score. The secondary endpoint variables were laboratory data, length of stay, and mortality, compared between thePF4/heparin Ab positive and negative groups. Results There was no significant difference in the 4Ts scores between the PF4/heparin Ab positive and negative groups. The positive predictive value (HIT patients/4T high score patients) was 15.4% (2/13), the negative predictive value (non-HIT patients/4T low score patients) was 87.5% (42/48), and the false-negative rate for the 4Ts score (4T low score patients/HIT patients) was as high as 54.5% (6/11). The PF4/heparin Ab positive patients had longer stay in intensive care compared to the PF4/heparin Ab negative patients (P = 0.035). Conclusions The present study showed the discrepancy between the 4Ts score and PF4/heparin Ab. When HIT is suspected in critically ill patients, an immediate HIT antibody test and initiation of therapeutic management of HIT are required regardless of the 4Ts score.
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Affiliation(s)
- Yosuke Matsumura
- Department of Emergency and Critical Care Medicine Chiba University Graduate School of Medicine Chiba Japan
| | - Taka-Aki Nakada
- Department of Emergency and Critical Care Medicine Chiba University Graduate School of Medicine Chiba Japan
| | - Shigeto Oda
- Department of Emergency and Critical Care Medicine Chiba University Graduate School of Medicine Chiba Japan
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Trehel-Tursis V, Louvain-Quintard V, Zarrouki Y, Imbert A, Doubine S, Stéphan F. Clinical and biologic features of patients suspected or confirmed to have heparin-induced thrombocytopenia in a cardiothoracic surgical ICU. Chest 2013; 142:837-844. [PMID: 22406956 DOI: 10.1378/chest.11-3074] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND The diagnosis of heparin-induced thrombocytopenia (HIT) is problematic in the surgical ICU, as there are multiple potential explanations for thrombocytopenia. We conducted a study to assess the incidence, clinical presentation, and outcome of HIT in a cardiothoracic surgical ICU. METHODS From January 2005 to December 2010, all patients with suspicion of HIT were prospectively identified, and data were collected retrospectively. Detection of anti-PF4/heparin antibodies and functional assays were systematically performed. RESULTS During the study period, 5,949 patients were admitted to the ICU (2,751 after cardiac surgery and 3,198 after thoracic surgery), of whom 101 were suspected to have HIT(1.7% [95% CI, 1.4%-2.0%]). Suspicion of HIT occurred at a median of 5 (4-9) days after ICU admission. Diagnosis was confirmed in 28 of 5,949 patients (0.47% [95% CI, 0.33%-0.68%]).Thrombosis was detected in 14 patients with HIT (50%) and in 12 patients without HIT (16%)( P 5 .0006). After receiver operating characteristic analysis (area under curve 5 0.78 0.06),a 4Ts score ≥ 5 had a sensitivity of 86% and a specificity of 70%. Course of platelet count was similar between the two groups. Six patients (21%) with HIT and 20 (27%) without died( P 5 .77). CONCLUSIONS Even with a prospective platelet monitoring protocol, suspicion for HIT arose in <2% of patients in a cardiothoracic ICU. Most were found to have other causes of thrombocytopenia,with HIT confirmed in 28 of 101 suspected cases (0.47% of all patients in the ICU). The 4Ts score may have value by identifying patients who should have laboratory testing performed.The mortality of patients with HIT was not different from other very ill thrombocytopenic patients in the ICU.
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Affiliation(s)
| | | | | | | | - Sylvie Doubine
- Hemostasis Laboratory, Centre Chirurgical Marie Lannelongue, Le Plessis Robinson, France
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Welp H, Ellger B, Scherer M, Lanckohr C, Martens S, Gottschalk A. Heparin-induced thrombocytopenia during extracorporeal membrane oxygenation. J Cardiothorac Vasc Anesth 2013; 28:342-4. [PMID: 23642887 DOI: 10.1053/j.jvca.2012.10.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2012] [Indexed: 11/11/2022]
Affiliation(s)
- Henryk Welp
- Department of Cardiac Surgery, University Hospital Münster, Germany.
| | - Björn Ellger
- Department of Anesthesiology, Intensive Care Medicine and Pain Therapy, University Hospital Münster, Germany
| | - Mirela Scherer
- Department of Cardiac Surgery, University Hospital Münster, Germany
| | - Christian Lanckohr
- Department of Anesthesiology, Intensive Care Medicine and Pain Therapy, University Hospital Münster, Germany
| | - Sven Martens
- Department of Cardiac Surgery, University Hospital Münster, Germany
| | - Antje Gottschalk
- Department of Anesthesiology, Intensive Care Medicine and Pain Therapy, University Hospital Münster, Germany
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Predictive value of the 4Ts scoring system for heparin-induced thrombocytopenia: a systematic review and meta-analysis. Blood 2012; 120:4160-7. [PMID: 22990018 DOI: 10.1182/blood-2012-07-443051] [Citation(s) in RCA: 289] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The 4Ts is a pretest clinical scoring system for heparin-induced thrombocytopenia (HIT). Although widely used in clinical practice, its predictive value for HIT in diverse settings and patient populations is unknown. We performed a systematic review and meta-analysis to estimate the predictive value of the 4Ts in patients with suspected HIT. We searched PubMed, Cochrane Database, and ISI Web of Science for studies that included patients with suspected HIT, who were evaluated by both the 4Ts and a reference standard against which the 4Ts could be compared. Quality of eligible studies was assessed by QUADAS-2 criteria. Thirteen studies, collectively involving 3068 patients, fulfilled eligibility criteria. A total of 1712 (55.8%) patients were classified by 4Ts score as having a low probability of HIT. The negative predictive value of a low probability 4Ts score was 0.998 (95% CI, 0.970-1.000) and remained high irrespective of the party responsible for scoring, the prevalence of HIT, or the composition of the study population. The positive predictive value of an intermediate and high probability 4Ts score was 0.14 (0.09-0.22) and 0.64 (0.40-0.82), respectively. A low probability 4Ts score appears to be a robust means of excluding HIT. Patients with intermediate and high probability scores require further evaluation.
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Lancaster C, Tobias JD. Why Is the Platelet Count Low: Should I Be Concerned About Heparin-Induced Thrombocytopenia? J Pediatr Pharmacol Ther 2012; 17:2-6. [DOI: 10.5863/1551-6776-17.1.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Christopher Lancaster
- Departments of Anesthesiology and Pediatrics, Nationwide Children's Hospital, and the Ohio State University, Columbus, Ohio
| | - Joseph D Tobias
- Departments of Anesthesiology and Pediatrics, Nationwide Children's Hospital, and the Ohio State University, Columbus, Ohio
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Abstract
Rapid laboratory assessment of heparin-induced thrombocytopenia (HIT) is important for disease recognition and management. The utility of contemporary immunoassays to detect antiplatelet factor 4 (PF4)/heparin antibodies is hindered by detection of antibodies unassociated with disease. To begin to distinguish properties of pathogenic anti-PF4/heparin antibodies, we compared isotype-matched monoclonal antibodies that bind to different epitopes: KKO causes thrombocytopenia in an in vivo model of HIT, whereas RTO does not. KKO binding to PF4 and heparin is specifically inhibited by human HIT antibodies that activate platelets, whereas inhibition of RTO binding is not differentially affected. Heparin increased the avidity of KKO binding to PF4 without affecting RTO, but it did not increase total binding or binding to nontetrameric PF4(K50E). Single-molecule forced unbinding demonstrated KKO was 8-fold more reactive toward PF4 tetramers and formed stronger complexes than RTO, but not to PF4(K50E) dimers. KKO, but not RTO, promoted oligomerization of PF4 but not PF4(K50E). This study reveals differences in the properties of anti-PF4 antibodies that cause thrombocytopenia not revealed by ELISA that correlate with oligomerization of PF4 and sustained high-avidity interactions that may simulate transient antibody-antigen interactions in vivo. These differences suggest the potential importance of epitope specificity in the pathogenesis of HIT.
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Abstract
Heparin-induced thrombocytopenia is a prothrombotic adverse drug effect induced by platelet-activating antibodies against multimolecular complexes of platelet factor 4 and heparin. Diagnosis rests on a clinical assessment of disease probability and laboratory testing. Management involves immediate discontinuation of heparin and initiation of an alternative anticoagulant. Because of the frequency of thrombocytopenia among heparinized patients, the limited specificity of widely available immunoassays, the limited availability of more specific functional assays, and clinicians' fears of missing a case of true disease, overtesting, overdiagnosis, and overtreatment have become common. As a result, a substantial number of thrombocytopenic patients are unnecessarily exposed to costly alternative anticoagulants and their attendant risk of bleeding. In this review, we describe not only our approach to the evaluation and management of patients with heparin-induced thrombocytopenia, but also the measures we use to minimize misdiagnosis and unnecessary treatment of patients without the disease. In addition, we propose areas of investigation for improvement of the diagnosis and management of this potentially fatal disorder.
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