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Early-onset and persisting thrombocytopenia in post-cardiac surgery patients is rarely due to heparin-induced thrombocytopenia, even when antibody tests are positive
Article first published online: 28 SEP 2009
DOI: 10.1111/j.1538-7836.2009.03626.x
© 2009 International Society on Thrombosis and Haemostasis
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How to Cite
SELLENG, S., MALOWSKY, B., STROBEL, U., WESSEL, A., ITTERMANN, T., WOLLERT, H.-G., WARKENTIN, T. E. and GREINACHER, A. (2010), Early-onset and persisting thrombocytopenia in post-cardiac surgery patients is rarely due to heparin-induced thrombocytopenia, even when antibody tests are positive. Journal of Thrombosis and Haemostasis, 8: 30–36. doi: 10.1111/j.1538-7836.2009.03626.x
Publication History
- Issue published online: 14 DEC 2009
- Article first published online: 28 SEP 2009
- Received 2 July 2009, accepted 17 September 2009
- Abstract
- Article
- References
- Cited By
Keywords:
- cardiopulmonary bypass;
- diagnosis;
- heparin-induced thrombocytopenia;
- platelets
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 27–29.
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: To examine how these platelet count profiles correlate with antibody status and HIT post-cardiac surgery. Methods: We prospectively screened 581 cardiac surgery patients for heparin-dependent 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 positive for platelet-activating anti-PF4–heparin IgG antibodies. In these patients, the frequency of heparin-dependent antibodies did not differ from that in non-thrombocytopenic controls, 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.