Thromboembolic events secondary to tirofiban-induced thrombocytopenia being treated with thrombopoietin: A case report

Critical Analysis of Thrombocytopenia Associated With Glycoprotein IIb/IIIa Inhibitors and Potential Role of Zalunfiban, a Novel Small Molecule Glycoprotein Inhibitor, in Understanding the Mechanism(s)

Thrombocytopenia is a rare but serious complication of the intravenous glycoprotein IIb/IIIa (GPIIb/IIIa; integrin αIIbβ3) receptor inhibitors (GPIs), abciximab, eptifibatide, and tirofiban. The thrombocytopenia ranges from mild (50 000-100 000 platelets/μL), to severe (20 000 to <50 000/μL), to profound (<20 000/μL). Profound thrombocytopenia appears to occur in <1% of patients receiving their first course of therapy. Thrombocytopenia can be either acute (<24 hours) or delayed (up to ~14 days). Both hemorrhagic and thrombotic complications have been reported in association with thrombocytopenia. Diagnosis requires exclusion of pseudothrombocytopenia and heparin-induced thrombocytopenia. Therapy based on the severity of thrombocytopenia and symptoms may include drug withdrawals and treatment with steroids, intravenous IgG, and platelet transfusions. Abciximab-associated thrombocytopenia is most common and due to either preformed antibodies or antibodies induced in response to abciximab (delayed). Readministration of abciximab is associated with increased risk of thrombocytopenia. Evidence also supports an immune basis for thrombocytopenia associated with the 2 small molecule GPIs. The latter bind αIIbβ3 like the natural ligands and thus induce the receptor to undergo major conformational changes that potentially create neoepitopes. Thrombocytopenia associated with these drugs is also immune-mediated, with antibodies recognizing the αIIbβ3 receptor only in the presence of the drug. It is unclear whether the antibody binding depends on the conformational change and whether the drug contributes directly to the epitope. Zalunfiban, a second-generation subcutaneous small molecule GPI, does not induce the conformational changes; therefore, data from studies of zalunfiban will provide information on the contribution of the conformational changes to the development of GPI-associated thrombocytopenia.

Tirofiban-induced thrombocytopenia

Tirofiban is a small non-peptide ligand-mimetic Glycoprotein (GP) IIb/IIIa inhibitor which can reversibly bind to the arginine-glycine-aspartic acid (RGD) recognition site of GP IIb/IIIa to prevent platelet aggregation. It reduces the incidence of thrombotic cardiovascular events in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS). Although generally considered safe, tirofiban has been reported to be associated with thrombocytopenia in several case reports and clinical trials. The pathogenesis for this adverse reaction is not entirely understood, is thought to be due to immune-mediated reaction. This side effect caused by tirofiban is especially concerning given how frequently it is used in the practice of contemporary cardiovascular care. The present review provides an overview of the pathophysiology, clinical presentation, management, and risk factors associated with tirofiban-induced thrombocytopenia.

A case report of acute myocardial infarction with extremely severe thrombocytopenia after percutaneous coronary intervention

INTRODUCTION

The case report's purpose is to remind doctors a rare complication named thrombocytopenia of antithrombotic drugs. As a result, severe bleeding or even life-threatening situations may be avoided.

PATIENT CONCERNS

A specific case of a patient with acute myocardial infarction, a significant decrease in platelet count was observed after percutaneous coronary intervention.

DIAGNOSIS

After ruling out other potential causes, the medical team considered tirofiban-induced thrombocytopenia as a possible explanation.

INTERVENTIONS AND OUTCOMES

Through careful monitoring and adjustment of medication, the patient's platelet count eventually returned to normal.

CONCLUSION

To ensure patient safety, it is advised to regularly monitor platelet counts at intervals of 2 to 6 hours before and after administering tirofiban.

Case Report: Life-threatening pancytopenia with tislelizumab followed by cerebral infarction in a patient with lung adenocarcinoma

Immune checkpoint inhibitors (ICIs) are an integral antitumor therapy for many malignancies. Most patients show very good tolerability to ICIs; however, serious immune-related adverse events (irAEs) with ICIs have been well documented and prevent some patients from continuing ICIs or even become the direct cause of patient death. Cytopenia is a rare irAE but can be life-threatening. Here, we present the case of a 66-year-old male patient with metastatic lung adenocarcinoma who received two doses of chemotherapy + PD-1 antibody tislelizumab and developed pancytopenia after each dose. Although the first episode of pancytopenia resolved with a treatment regimen of granulocyte colony-stimulating factor (G-CSF), thrombopoietin (TPO), and red blood cell and platelet transfusion, the second episode showed extreme resistance to these treatments and improved only after the administration of steroids. His second pancytopenia episode resolved after a long course of treatment with methylprednisolone, G-CSF, TPO, hetrombopag and multiple red blood cell and platelet transfusions. However, he suffered a cerebral infarction when his platelet count was in the normal range and gradually recovered 1 week later. This case highlights the importance of the early recognition and management of hematological irAEs.

Tirofiban Induced Thrombocytopenia: A Rare but Severe Adverse Effect

With the advent of medical technology, coronary angiography is a common practice to evaluate patient for coronary artery disease. Normally, patients undergoing angiogram receive antiplatelets, anticoagulants, and platelet aggregation inhibitor agents. Glycoprotein IIb/IIIa receptor inhibitors are a type of platelets antiaggregant agents that can cause severe thrombocytopenia in very few cases. We present a case of a 69-year-old female who presented with chest pain, underwent an angiography and had two stents placed. She was administered tirofiban during angiogram that caused acute severe thrombocytopenia decreasing her platelets count from 224 to 2 k/mm³ within 1 day. Patients platelets gradually recovered after trial of steroid and platelets transfusion. Antiplatelets (Aspirin and Clopidogrel) were resumed; however, patient’s platelets remained stable.

An Unusual Case of Drug-Induced Thrombocytopenia

Drug-induced thrombocytopenia (DIT) is a differential diagnosis for consideration when acute thrombocytopenia is encountered in the outpatient or inpatient setting. The mechanism of thrombocytopenia induced by different antiplatelet therapies varies. DIT may occur due to antibody formation following the exposure to a drug, or naturally occurring preexisting antibodies may produce rapid-onset thrombocytopenia when a drug molecule binds to a platelet receptor inducing a conformational change thus rendering it to be an antigen target for naturally occurring antibodies. A 66-year-old female with history of hypertension presented with non-ST elevation myocardial infarction, had drug eluting stent placed in first obtuse marginal artery of left circumflex coronary artery. Started on antiplatelet medications aspirin 81 mg, ticagrelor 90 mg (which was later transitioned to clopidogrel 75 mg), as well as tirofiban 12.5 mg (for 12 hours only). Tirofiban is a GP IIb/IIIa antagonist, other drugs in this class have been documented to induce thrombocytopenia as well, but rates for tirofiban appear to be the highest, the reason is unclear. These antibodies are thought to be either naturally occurring or induced from conformational changes to GP IIb/IIIa binding site after binding to the GP IIb/IIIa receptor, binding of these drugs to the receptor precipitates an epitope much more specific for platelet surface antigens. Tirofiban and clopidogrel/ticagrelor can cause thrombocytopenia, but onset in this case is unusual: acute antibody reaction would be expected within hours, not delayed 30 hours after starting antiplatelet medication, and nonacute reaction would present 1 to 2 weeks out.

[Long-lasting thrombocytopenia induced by glycoprotein IIb/IIIa inhibitor]

INTRODUCTION

Glycoprotein IIb/IIIa inhibitors (anti-GPIIbIIIa) prevent platelet binding to fibrinogen. Transient sometimes-severe thrombocytopenia is a well-known side effect.

OBSERVATION

A 71-year-old patient presented severe thrombocytopenia after the administration of tirofiban (anti-GPIIbIIIa). Corticosteroid treatment was initiated at day 10 because of persistence of severe thrombocytopenia with poor platelet transfusion efficacy. Corticosteroid treatment led to platelet recovery evoking an immune mediated mechanism for thrombocytopenia.

CONCLUSION

Anti-GPIIbIIIa are associated with a risk of dramatic thrombocytopenia. The underlying mechanism is poorly understood. The management of these usually transient thrombocytopenias is based on platelet transfusion. As report here, in some cases persistent thrombocytopenia can respond to corticosteroids.