Combination platelet glycoprotein IIb/IIIa receptor and lepirudin administration during percutaneous coronary intervention in patients with heparin-induced thrombocytopenia

[Heparin-Induced Thrombocytopenia]

The extensive use of therapeutic doses of heparin to prevent thrombosis in critically ill patients with COVID-19 during the pandemic has led to an increased incidence of bleeding and heparin-induced thrombocytopenia (HIT). In addition, the introduction of the AstraZeneca and Johnson&Johnson vaccines against COVID-19 into clinical practice was associated with the development of a rare but very severe, adverse thrombotic complication, vaccine-induced immune thrombotic thrombocytopenia (VITT). Thrombotic complications of VITT turned out to be similar to HIT both clinically and pathophysiologically. HIT is a potentially fatal immune-mediated adverse drug response that results in emergence of antibodies that activate platelets in the presence of heparin. HIT is characterized by a high incidence of venous and arterial thromboses, often with fatal outcomes. Currently, there are clearly defined international guidelines for the diagnosis, treatment and prevention of HIT. In case of thrombotic complications, non-heparin anticoagulants should be used.

Treatment and prevention of heparin-induced thrombocytopenia: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition)

This chapter about the recognition, treatment, and prevention of heparin-induced thrombocytopenia (HIT) is part of the Antithrombotic and Thrombolytic Therapy: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs. Grade 2 suggests that individual patient values may lead to different choices. Among the key recommendations in this chapter are the following: For patients receiving heparin in whom the clinician considers the risk of HIT to be > 1.0%, we recommend platelet count monitoring over no platelet count monitoring (Grade 1C). For patients who are receiving heparin or have received heparin within the previous 2 weeks, we recommend investigating for a diagnosis of HIT if the platelet count falls by >/= 50%, and/or a thrombotic event occurs, between days 5 and 14 (inclusive) following initiation of heparin, even if the patient is no longer receiving heparin therapy when thrombosis or thrombocytopenia has occurred (Grade 1C). For patients with strongly suspected (or confirmed) HIT, whether or not complicated by thrombosis, we recommend use of an alternative, nonheparin anticoagulant (danaparoid [Grade 1B], lepirudin [Grade 1C], argatroban [Grade 1C], fondaparinux [Grade 2C], or bivalirudin [Grade 2C]) over the further use of unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH) therapy or initiation/continuation of vitamin K antagonists (VKAs) [Grade 1B]. The guidelines include specific recommendations for nonheparin anticoagulant dosing that differ from the package inserts. For patients with strongly suspected or confirmed HIT, we recommend against the use of vitamin K antagonist (VKA) [coumarin] therapy until after the platelet count has substantially recovered (usually, to at least 150 x 10(9)/L) over starting VKA therapy at a lower platelet count (Grade 1B); that VKA therapy be started only with low maintenance doses (maximum, 5 mg of warfarin or 6 mg of phenprocoumon) over higher initial doses (Grade 1B); and that the nonheparin anticoagulant (eg, lepirudin, argatroban, danaparoid) be continued until the platelet count has reached a stable plateau, the international normalized ratio (INR) has reached the intended target range, and after a minimum overlap of at least 5 days between nonheparin anticoagulation and VKA therapy rather than a shorter overlap (Grade 1B). For patients receiving VKAs at the time of diagnosis of HIT, we recommend use of vitamin K (10 mg po or 5 to 10 mg IV) [Grade 1C].

[Heparin-induced thrombocytopenia]

Hemorrhage is the most common and best-recognized complication of heparin treatment. However, a potentially more dangerous complication is the development of heparin-induced thrombocytopenia (HIT). All patients exposed to heparin, irrespective of the dose and route of administration, are at risk of developing HIT. It is due to the formation of antibodies against the heparin-platelet factor 4 complex, which cause secondary activation of platelets, coagulation and, finally, increased thrombin production. The main symptom is the sudden onset of thrombocytopenia involving a drop in the platelet count to less than 50% of the basal level, with or without the appearance of thrombotic complications some 5 to 14 days after the start of heparin therapy. Heparin-induced thrombocytopenia can be detected early in patients receiving heparin by monitoring the platelet count. Demonstration of heparin-dependent platelet activation using an antigen or functional assay confirms the clinical diagnosis. Once the diagnosis of HIT has been confirmed serologically or there is a high level of suspicion of HIT, heparin must be suspended and treatment with an alternative anticoagulant should be considered. This review contains a discussion of the diagnosis and treatment of this syndrome.

Percutaneous coronary interventions in patients with heparin-induced thrombocytopenia

Accomplishing a successful percutaneous coronary intervention in a patient with a suspected or diagnosed heparin-induced thrombocytopenia (HIT) requires the selection of an appropriate alternative anticoagulant and a thorough assessment of bleeding and thrombotic risks. In this review, we suggest an evidence-based management algorithm that takes into account the clinical phase of HIT (acute, recent, and remote HIT) and the associated risk when patients present with acute coronary syndrome. The algorithm also integrates preventive measures directed at decreasing the bleeding risk associated with the antithrombotic and invasive therapies used for HIT and percutaneous coronary intervention.

Heparin induced thrombocytopenia: diagnosis and management update

Heparin-induced thrombocytopenia (HIT) is a potentially devastating immune mediated adverse drug reaction caused by the emergence of antibodies that activate platelets in the presence of heparin. Despite thrombocytopenia, bleeding is rare; rather, HIT is strongly associated with thromboembolic complications involving both the arterial and venous systems. A number of laboratory tests are available to confirm the diagnosis; however, when HIT is clinically suspected, treatment should not be withheld pending the result. Fortunately, therapeutic strategies have been refined, and new and effective therapeutic agents are available. Treatment options are focused on inhibiting thrombin formation or direct thrombin inhibition. Warfarin should not be used until the platelet count has recovered.

Direct thrombin inhibition during percutaneous coronary intervention in patients with heparin-induced thrombocytopenia

Patients with or at risk of heparin-induced thrombocytopenia (HIT) who are undergoing percutaneous coronary intervention (PCI) are at particular risk of thrombosis due to the prothrombotic nature of HIT and the endovascular disruption from PCI. Patients require aggressive anticoagulation during PCI, and alternative, nonheparin anticoagulation is recommended over heparin in patients with acute or previous HIT. Argatroban, bivalirudin, and lepirudin are nonheparin, fast-acting, parenteral direct thrombin inhibitors (DTIs). Multicenter, prospective studies have demonstrated that argatroban and lepirudin each reduce thrombosis in HIT and that argatroban and bivalirudin each provide adequate anticoagulation during PCI in patients with or at risk of HIT. We review current therapeutic practices with direct thrombin inhibitors in patients with or at risk of HIT during PCI, including individuals requiring periprocedural anticoagulation, and the factors influencing the choice of DTI in this setting.