Heparin-induced thrombocytopenia (HIT): The use of platelet transfusion

One of the topics of discussion this week was the utilization of platelet transfusions in patients with heparin-induced thrombocytopenia.

Goel R, et al. Platelet transfusions in platelet consumptive disorders are associated with arterial thrombosis and in-hospital mortality. Blood. 2015 Feb 26;125(9):1470-6.

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While platelets are primary mediators of hemostasis, there is emerging evidence to show that they may also mediate pathologic thrombogenesis. Little data are available on risks and benefits associated with platelet transfusions in thrombotic thrombocytopenic purpura (TTP), heparin-induced thrombocytopenia (HIT) and immune thrombocytopenic purpura (ITP). This study utilized the Nationwide Inpatient Sample to evaluate the current in-hospital platelet transfusion practices and their association with arterial/venous thrombosis, acute myocardial infarction (AMI), stroke, and in-hospital mortality over 5 years (2007-2011). Age and gender-adjusted odds ratios (adjOR) associated with platelet transfusions were calculated. There were 10 624 hospitalizations with TTP; 6332 with HIT and 79 980 with ITP. Platelet transfusions were reported in 10.1% TTP, 7.1% HIT, and 25.8% ITP admissions. Platelet transfusions in TTP were associated with higher odds of arterial thrombosis (adjOR = 5.8, 95%CI = 1.3-26.6), AMI (adjOR = 2.0, 95%CI = 1.2-3.3) and mortality (adjOR = 2.0,95%CI = 1.3-3.0), but not venous thrombosis. Platelet transfusions in HIT were associated with higher odds of arterial thrombosis (adjOR = 3.4, 95%CI = 1.2-9.5) and mortality (adjOR = 5.2, 95%CI = 2.6-10.5) but not venous thrombosis. Except for AMI, all relationships remained significant after adjusting for clinical severity and acuity. No associations were significant for ITP. Platelet transfusions are associated with higher odds of arterial thrombosis and mortality among TTP and HIT patients.

Salter BS, et al. Heparin-Induced Thrombocytopenia: A Comprehensive Clinical Review. J Am Coll Cardiol. 2016 May 31;67(21):2519-32.

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“Because of the limited evidence available, the 2012 American College of Chest Physicians (ACCP) guidelines do not recommend routine platelet transfusion in patients with HIT. However, they do support transfusions to severely thrombocytopenic patients with HIT who are bleeding or necessitate transfusion during the performance of an invasive procedure with a high risk for bleeding (6). More recently, Goel et al. (90) further stratified the risk for platelet transfusion by using the Nationwide Inpatient Sample registry, producing results from the largest available inpatient database. Among those diagnosed with HIT, 7.1% received platelet transfusions; 20.6% of these patients experienced thrombotic complications, revealing a significant association between platelet transfusions and arterial thrombotic events in HIT.”

East JM, Cserti-Gazdewich CM, Granton JT. Heparin-Induced Thrombocytopenia in the Critically Ill Patient. Chest. 2018 Sep;154(3):678-690.

Full-text for Emory users.

“Transfusion thresholds for states of thrombotic thrombocytopenia are not established, and studies in some conditions (such as thrombotic thrombocytopenic purpura or antiphospholipid antibody syndrome) may not be generalizable to HIT.80, 81 Platelet needs or hazards in the patient suspected of having HIT may not be different from those with other forms of platelet insufficiency. Given the high bleeding risk of patients in the ICU, and perioperative patients in particular, the bleeding risk (by deferring platelet transfusion) may outweigh that of theoretical thrombosis (with platelet transfusion). If HIT is confirmed, then consultation from hematology or thrombosis services should help guide platelet thresholds in a patient with HIT confirmed on an individualized basis.”

DynaMed. (2019, August 30). Heparin-Induced Thrombocytopenia (HIT). Ipswich, MA: EBSCO Information Services. Retrieved November 15, 2019.

More PubMed results on HIT.

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