Heparin-induced thrombocytopenia is rare in pregnancy

Fausett, M. Bardett; Vogtländer, M F; Lee, R.M.; Esplin, M. Sean; Branch, D. Ware; Rodgers, George M.; Silver, Robert M.

doi:10.1067/mob.2001.114690

Cited by 116 publications

(32 citation statements)

References 19 publications

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“…19,20 Patients who undergo cardiac or orthopedic surgery and receive UFH have a higher risk of HIT (1%-5%) than medical or obstetric patients (0.1%-1%). 13,14,[21][22][23][24] Women have approximately twice the risk of developing HIT as men. 18 Table 2 [25][26][27][28][29][30][31][32][33][34][35] presents the incidence of HIT in various patient populations.…”

Section: 2mentioning

confidence: 99%

Treatment and Prevention of Heparin-Induced Thrombocytopenia

Linkins

Dans

Moores

et al. 2012

Chest

848

335

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Section: 2mentioning

confidence: 99%

Treatment and Prevention of Heparin-Induced Thrombocytopenia

Linkins

Dans

Moores

et al. 2012

Chest

848

335

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“…However, certain observations suggest that non-drug factors could also influence risk of HIT. For example, one meta-analysis [4] found that postsurgery patients are more likely than medical patients to develop HIT, and another study [5] reported that pregnant women are less likely than non-pregnant females to develop HIT.…”

Section: Introductionmentioning

confidence: 99%

Anti‐PF4/heparin antibody formation postorthopedic surgery thromboprophylaxis: the role of non‐drug risk factors and evidence for a stoichiometry‐based model of immunization

Warkentin

Cook

Marder

et al. 2010

Journal of Thrombosis and Haemostasis

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To cite this article: Warkentin TE, Cook RJ, Marder VJ, Greinacher A. Anti-PF4/heparin antibody formation postorthopedic surgery thromboprophylaxis: the role of non-drug risk factors and evidence for a stoichiometry-based model of immunization. J Thromb Haemost 2010; 8: 504-12.Summary. Background: Heparin-induced thrombocytopenia is an antibody-mediated disorder exhibiting variable frequency in different clinical settings. Antibodies recognize PF4/heparin complexes formed at optimal stoichiometric molar ratios. Objective: To identify clinical factors influencing risk of anti-PF4/heparin immunization. Patients/methods: We performed observational studies and exploratory analyses of the frequency of anti-PF4/heparin antibody formation in 6324 patients who received enoxaparin or fondaparinux in four randomized controlled trials of postorthopedic surgery thromboprophylaxis. Variables included surgery type (knee vs. hip), timing of first anticoagulant dose (pre-vs. postsurgery), circumstances of surgery (elective vs. hip fracture), anticoagulant (enoxaparin vs. fondaparinux) and body-mass index (BMI). We applied a stoichiometry-based model that predicts immunization risk based on expected differences in PF4/anticoagulant ratios in different settings, and specifically used this model to predict the effect of increasing BMI quartiles upon relative risk (RR) of immunization for fondaparinux vs. enoxaparin. Results: Anti-PF4/heparin immunization was more frequent after knee vs. hip surgery (particularly for enoxaparin), and when enoxaparin was given post-rather than pre-elective surgery; however, the opposite occurred with hip fracture surgery, that is, antibody formation was more frequent when enoxaparin or fondaparinux was given presurgery. The RR of immunization for fondaparinux vs. enoxaparin decreased significantly for increasing BMI quartiles, an effect predominantly because of increasing immunization with enoxaparin at increasing BMI quartiles. Conclusions: Several non-drug factors -including type and circumstances of surgery, timing of first anticoagulant dose and BMI -influence risk of anti-PF4/heparin antibody formation, consistent with a stoichiometry-based immunization model of PF4 and anticoagulant ratios occurring during the early perioperative period.

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“…31 According to hospitalwide surveillance studies of 32-to 36-month duration, HIT occurred in 1.2% of all patients who received heparin for Ͼ4 days 32 and in 1.0% of all inpatients receiving any form of heparin. 30 …”

Section: Frequencymentioning

confidence: 99%

“…21,26 -28 HIT, while reported in obstetric patients, 29 is rare, occurring in one study in no (0/244) heparin-treated pregnant females yet in 4% (10/244) of nonpregnant controls. 30 Despite variability in the frequency of HIT, patients of any age receiving any type of heparin at any dose by any route of administration can develop HIT. 31 According to hospitalwide surveillance studies of 32-to 36-month duration, HIT occurred in 1.2% of all patients who received heparin for Ͼ4 days 32 and in 1.0% of all inpatients receiving any form of heparin.…”

Section: Frequencymentioning

confidence: 99%