American Society of Hematology 2018 guidelines for management of venous thromboembolism: heparin-induced thrombocytopenia

Abstract

Background: Heparin-induced thrombocytopenia (HIT) is an adverse drug reaction mediated by platelet-activating antibodies that target complexes of platelet factor 4 and heparin. Patients are at markedly increased risk of thromboembolism. Objective: These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians, and other health care professionals in their decisions about diagnosis and management of HIT. Methods: ASH formed a multidisciplinary guideline panel balanced to minimize potential bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline development process, including updating or performing systematic evidence reviews. The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess evidence and make recommendations, which were subject to public comment. Results: The panel agreed on 33 recommendations. The recommendations address screening of asymptomatic patients for HIT, diagnosis and initial management of patients with suspected HIT, treatment of acute HIT, and special situations in patients with acute HIT or a history of HIT, including cardiovascular surgery, percutaneous cardiovascular intervention, renal replacement therapy, and venous thromboembolism prophylaxis. Conclusions: Strong recommendations include use of the 4Ts score rather than a gestalt approach for estimating the pretest probability of HIT and avoidance of HIT laboratory testing and empiric treatment of HIT in patients with a low-probability 4Ts score. Conditional recommendations include the choice among non-heparin anticoagulants (argatroban, bivalirudin, danaparoid, fondaparinux, direct oral anticoagulants) for treatment of acute HIT.

The risk of major bleeding in patients with suspected heparin‐induced thrombocytopenia

“…Clinical practice guidelines recommend that patients with suspected HIT and an intermediate or high 4Ts score be treated empirically with an alternative anticoagulant while awaiting the results of HIT laboratory testing . While such a recommendation incorporates an estimate of the risk of HIT (and therefore the risk of thrombosis) into clinical decision making, it does not include a formal assessment of bleeding risk.…”

“…Thus, clinical prediction scores such as the 4Ts score or HIT Expert Probability (HEP) score are useful for estimating the pre‐test likelihood of HIT and guiding initial management decisions . With an intermediate or high score, clinical practice guidelines recommend stopping heparin and starting an alternative anticoagulant while awaiting confirmatory laboratory test results …”

Chinese expert consensus on diagnosis and treatment of coagulation dysfunction in COVID-19

“…For patients with a high likelihood of or confirmed HIT, the use of heparin should be discontinued and they should be switched to non-heparin anticoagulants such as argatroban or bivalirudin [33]. 1) Argatroban: Patients who are allergic to heparin or HIT can choose argatroban anticoagulation.…”

Fondaparinux in heparin‐induced thrombocytopenia: A decade's worth of clinical experience

“…The release of the American Society of Hematology (ASH) 2018 guidelines for management of venous thromboembolism: heparin‐induced thrombocytopenia (HIT), after this writing, recommended the use of fondaparinux in the treatment of acute HIT with thromboembolic complications. Despite the reference to the very low certainty in the evidence about effects, no preference is suggested for non‐heparin anticoagulants over fondaparinux in these guidelines.…”

“…Looking at the different guideline recommendations from various professional or governmental associations reveals that these differ not only in methodological aspects but as well in their conclusions drawn . While some guidelines recommend the use of fondaparinux, fondaparinux carries a level 2C recommendation from the American College of Chest Physicians (ACCP) . However, ACCP held out the prospect of readjusting their recommendations once more clinical evidence has emerged.…”