Thrombocytopenia in Acute Coronary Syndromes: Etiologies and Proposed Management

Severe thrombocytopenia induced by tirofiban after percutaneous coronary intervention: a case report

BACKGROUND

Tirofiban is a nonpeptide glycoprotein IIb/IIIa receptor antagonist used widely in patients subjected to percutaneous coronary intervention. While the usage of tirofiban sets an important clinical benefit, severe thrombocytopenia can occur with use of this agent.

CASE PRESENTATION

A 76-year-old Chinese man was admitted with 1-month history of sudden onset of chest tightness. He was diagnosed as having subacute inferior myocardial infarction, and percutaneous coronary intervention was performed. After the procedure, patient received tirofiban at 0.15 µg/kg/minute for 4 h. A blood sample was obtained for a complete blood count; severe thrombocytopenia was reported according to routine orders at our hospital. All antiplatelet drugs including tirofiban, aspirin, and clopidogrel were immediately discontinued. The patient received platelet transfusions and was treated with immunoglobulin G. Two days later, the patient's platelet count had increased to 75 × 109/L. There was a significant improvement after day 5, and the platelet count was 112 × 109/L. Seven days after the acute thrombocytopenia, he was discharged with normal platelet count.

CONCLUSIONS

Clinicians should be particularly aware of tirofiban-induced thrombocytopenia in routine practice.

Prognostic Value of Multiple Complete Blood Count-Derived Indices in Intermediate Coronary Lesions

Complete blood count (CBC)-derived indices have been proposed as reliable inflammatory biomarkers to predict outcomes in the context of coronary artery disease. These indices have yet to be thoroughly validated in patients with intermediate coronary stenosis. Our study included 1527 patients only with intermediate coronary stenosis. The examined variables were neutrophil-lymphocyte ratio (NLR), derived NLR, monocyte-lymphocyte ratio (MLR), platelet-lymphocyte ratio (PLR), systemic immune inflammation index (SII), system inflammation response index (SIRI), and aggregate index of systemic inflammation (AISI). The primary endpoint was the composite of major adverse cardiovascular events (MACEs), including all-cause death, non-fatal myocardial infarction, and unplanned revascularization. Over a follow-up of 6.11 (5.73-6.55) years, MACEs occurred in 189 patients. Receiver operator characteristic curve analysis showed that SIRI outperformed other indices with the most significant area under the curve. In the multivariable analysis, SIRI (hazard ratio [HR] 1.588, 95% confidence interval [CI] 1.138-2.212) and AISI (HR 1.673, 95% CI 1.217-2.300) were the most important prognostic factors among all the indices. The discrimination ability of each index was strengthened in patients with less burden of modifiable cardiovascular risk factors. SIRI also exhibited the best incremental value beyond the traditional cardiovascular risk model.

Eptifibatide, an Older Therapeutic Peptide with New Indications: From Clinical Pharmacology to Everyday Clinical Practice

Therapeutic peptides are oligomers or short polymers of amino acids used for various medical purposes. Peptide-based treatments have evolved considerably due to new technologies, stimulating new research interests. They have been shown to be beneficial in a variety of therapeutic applications, notably in the treatment of cardiovascular disorders such as acute coronary syndrome (ACS). ACS is characterized by coronary artery wall damage and consequent formation of an intraluminal thrombus obstructing one or more coronary arteries, leading to unstable angina, non-ST elevated myocardial infarction, and ST-elevated myocardial infarction. One of the promising peptide drugs in the treatment of these pathologies is eptifibatide, a synthetic heptapeptide derived from rattlesnake venom. Eptifibatide is a glycoprotein IIb/IIIa inhibitor that blocks different pathways in platelet activation and aggregation. In this narrative review, we summarized the current evidence on the mechanism of action, clinical pharmacology, and applications of eptifibatide in cardiology. Additionally, we illustrated its possible broader usage with new indications, including ischemic stroke, carotid stenting, intracranial aneurysm stenting, and septic shock. Further research is, however, required to fully evaluate the role of eptifibatide in these pathologies, independently and in comparison to other medications.

Complications and Management of Eptifibatide-Induced Thrombocytopenia

BACKGROUND

Eptifibatide is used in acute coronary syndromes to reversibly block platelet aggregation by inhibiting the platelet glycoprotein IIb/IIIa receptor. A serious adverse effect of eptifibatide is a profound drop in platelet count, termed eptifibatide-induced thrombocytopenia (EIT).

OBJECTIVE

To provide insight into the types of complications and management of EIT.

METHODS

Cases of EIT submitted to the Food and Drug Administration adverse event reporting system were evaluated. Data analyses included management of EIT, complications of thrombocytopenia, initial platelets, and platelet nadir following eptifibatide.

RESULTS

103 cases of EIT were reported from January 2010 to 2019; 57 cases met the Naranjo scale and were included. Only 37 of those cases contained information on how EIT was managed. Eptifibatide administration was withheld in all 37 of those cases. Platelet transfusions were administered in 20 cases (54%). Two cases were managed with steroids (5.4%), and 1 case used intravenous immunoglobulin G to reverse EIT (2%). The median initial platelet count prior to administration of eptifibatide was 207 000 cells/mm³ (SD = 69 000; n = 27), and median platelet nadir was 9000 cells/mm³ (SD = 19 000; n = 35) The majority of complications of EIT included bleeding events (16/28, 57%). Delayed procedures, prolonged stay, allergic reactions, and thrombosis were each reported in 3 patients (10.75%).

CONCLUSION AND RELEVANCE

Most cases of EIT were managed by withholding eptifibatide with platelet transfusion if necessary. The majority of complications included bleeding. However, significant procedure delays, prolonged hospital stay, thrombosis, and allergic reactions were also reported.

A Rare Case of Ticagrelor-Induced Profound Isolated Thrombocytopenia

Ticagrelor is a new oral antiplatelet drug that has a strong proven benefit of reducing the rate of death from cardiovascular causes, myocardial infarction, and stroke compared with clopidogrel. Ticagrelor is widely used by patients with acute coronary syndrome. However, profound thrombocytopenia has never been previously reported in such patients. We herein present our experience with a case of profound thrombocytopenia after ticagrelor administration. No drug possibly associated with thrombocytopenia was concomitantly prescribed. The patient's platelet count recovered rapidly after ticagrelor and platelet transfusion were discontinued.