An Improved Definition of Immune Heparin-Induced Thrombocytopenia in Postoperative Orthopedic Patients

Warkentin, Theodore E.; Roberts, Robin S.; Hirsh, Jack; Kelton, John G.

doi:10.1001/archinte.163.20.2518

Cited by 302 publications

(284 citation statements)

References 31 publications

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“…profile 1 ([a platelet count fall by > 50% (from the postoperative peak) between days 5 and 10 postsurgery] [12], and profile 2 (early-onset and persisting thrombocytopenia) [9,13]. Early-onset and persisting thrombocytopenia was defined as platelet counts that decreased within the first 4 days after surgery and remained below 100 · 10 9 L )1 until at least the seventh postoperative day.…”

Section: Assessing Platelet Count Changesmentioning

confidence: 99%

Early‐onset and persisting thrombocytopenia in post‐cardiac surgery patients is rarely due to heparin‐induced thrombocytopenia, even when antibody tests are positive

Selleng

Malowsky²,

Strobel

et al. 2010

Journal of Thrombosis and Haemostasis

158

123

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thrombocytopenia in post-cardiac surgery patients is rarely due to heparin-induced thrombocytopenia, even when antibody tests are positive. See also Gruel Y, Pouplard C. Post-operative platelet count profile: the most reliable tool for identifying patients with true heparin-induced thrombocypenia after cardiac surgery. This issue, pp 27-9.Summary. Background: The high frequency of thrombocytopenia in post-cardiac surgery patients makes it challenging to diagnose heparin-induced thrombocytopenia (HIT). Two platelet count profiles are reported as indicating possible HIT in these patients: profile 1 describes a platelet count fall that begins between postoperative days 5 and 10, whereas profile 2 denotes early-onset thrombocytopenia that persists beyond day 5. Objectives: Toexaminehowthese platelet count profiles correlate withantibodystatusandHITpost-cardiacsurgery.Methods:We prospectively screened 581 cardiac surgery patients for heparindependent antibodies by platelet factor 4 (PF4)-heparin immunoassay and platelet-activation test, and performed daily platelet counts (until day 10) with 30-day follow-up. Results: All three patients with platelet count profile 1 tested positive for platelet-activating anti-PF4-heparin IgG antibodies [odds ratio (OR) 521.7, 95% confidence interval (CI) 3.9-34 000, P = 0.002], and were judged to have HIT. In contrast, none of 25 patients with early-onset and persisting thrombocytopenia (profile 2) was judged to have HIT, including five patients testing positivefor platelet-activating anti-PF4-heparin IgG antibodies. In these patients, the frequency of heparin-dependent antibodies didnot differfromthat in non-thrombocytopeniccontrols, either for anti-PF4-heparin IgG (OR 1.7, 95% CI 0.7-4.1, P = 0.31) or for platelet-activating antibodies (OR 1.9, 95% CI 0.6-5.7, P = 0.20). Multivariate analysis revealed that type of cardiac surgery, but not HIT antibody status, predicted early-onset and persisting thrombocytopenia. Together, these findings show that HIT was uncommon in this study population [overall frequency, 3/581 (0.5%), 95% CI 0.1-1.5%]. Conclusions: Thrombocytopenia that begins between 5 and 10 days post-cardiac surgery is highly predictive for HIT. In contrast, early-onset and persisting thrombocytopenia is usually caused by non-HIT factors with coinciding heparin-dependent antibody seroconversion.

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Section: Assessing Platelet Count Changesmentioning

confidence: 99%

Early‐onset and persisting thrombocytopenia in post‐cardiac surgery patients is rarely due to heparin‐induced thrombocytopenia, even when antibody tests are positive

Selleng

Malowsky²,

Strobel

et al. 2010

Journal of Thrombosis and Haemostasis

158

123

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“…In that respect, it is both highly sensitive [37] and specific, because positive reactions are extremely rare in patients not exposed to heparin [30]. In various studies, 2-13% of patients thought to have HIT on clinical grounds were antibody-negative [40][41][42][43], but it is impossible to know how many of them may have had some other cause for their thrombocytopenia. In our experience, it is extremely rare for patients with ''typical'' HIT, especially those with associated thromboses, not to test positive in the ELISA.…”

Section: Solid-phase Assaysmentioning

confidence: 99%

Heparin‐induced thrombocytopenia and thrombosis

Davoren

Aster

2005

American J Hematol

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Heparin, employed clinically for more than 50 years, is still a widely used anticoagulant. Unfortunately, some patients given this agent develop thrombocytopenia and thrombosis. Because this side effect can have catastrophic consequences, it is imperative that all clinicians caring for patients who receive heparin have at least a basic understanding of its pathogenesis, diagnosis, and management. Am. J. Hematol. 81:36-44, 2006Hematol. 81:36-44, . ª 2005 Wiley-Liss, Inc.

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“…In addition, this system has a method of alerting nurses and physicians if the platelet count drops below 100,000 platelets/mm 3 , with a resulting notification rate of 6% for all patients monitored by the HNS system. Our HIT CDSS had a notification rate of 13%; the difference may reflect our more sensitive definition of HIT [4]. Evans and colleagues described a CDSS to help with the appropriate selection of antibiotics.…”

Section: Discussionmentioning

confidence: 91%

“…The incidence of HIT ranges from 1-3% depending on the type of heparin product and patient population [2,3]. Criteria for the diagnosis of HIT in patients treated with heparin products include either a significant proportional platelet count decrease (for example, a 50% decrease from maximum value), or a decrease below a specified threshold (for example, 150,000 platelets/mm 3 ) [4][5]. The highest risk of developing HIT occurs between 5 and 10 days of initial exposure to unfractionated (UFH) or low molecular weight heparin (LMWH) [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Effectiveness of a clinical decision support system to identify heparin induced thrombocytopenia

Riggio

Cooper

Leiby

et al. 2008

J Thromb Thrombolysis

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An Improved Definition of Immune Heparin-Induced Thrombocytopenia in Postoperative Orthopedic Patients

Abstract: A 50% or greater fall in the platelet count from the postoperative peak is a sensitive definition indicating possible HIT that is associated with an increased risk of thrombosis.

Cited by 302 publications

References 31 publications

Early‐onset and persisting thrombocytopenia in post‐cardiac surgery patients is rarely due to heparin‐induced thrombocytopenia, even when antibody tests are positive

Early‐onset and persisting thrombocytopenia in post‐cardiac surgery patients is rarely due to heparin‐induced thrombocytopenia, even when antibody tests are positive

Heparin‐induced thrombocytopenia and thrombosis

Effectiveness of a clinical decision support system to identify heparin induced thrombocytopenia

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