Myocardial infarction is a life-threatening emergency with a high mortality rate. A high plasma level of factor VIII is an established risk for both arterial and venous thrombotic events. In this mini-review, we report the case of a 41-year-old woman without cardiovascular risk factors or a previous history of thrombotic events, admitted for ST-elevation myocardial infarction, in whom coronary angiography showed a thrombotic occlusion in the left anterior descending artery. The patient underwent primary percutaneous coronary intervention (PCI), with GPIIB-IIIA antagonist, then, a pre-dilation with a semi-compliant balloon-catheter, followed by implantation of 2 stents. The etiological assessment revealed a high level of coagulation factor VIII (FVIII). She underwent anticoagulation therapy (with acenocoumarol) with well-controlled international normalised ratio (INR).

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.

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BACKGROUND: Animal models have been instrumental in defining thrombus formation, including the role of platelet surface glycoprotein (GP) receptors, in acute ischemic stroke (AIS). However, the involvement of GP receptors in human ischemic stroke pathophysiology and their utility as biomarkers for ischemic stroke risk and severity requires elucidation.
OBJECTIVE: To determine whether platelet GPIb and GPIIb/IIIa receptors are differentially expressed in patients with AIS and chronic cerebrovascular disease (CCD) compared with healthy volunteers (HV) and to identify predictors of GPIb and GPIIb/IIIa expression.
METHODS: This was a case-control study of 116 patients with AIS or transient ischemic attack (TIA), 117 patients with CCD, and 104 HV who were enrolled at our University hospital from 2010 to 2013. Blood sampling was performed once in the CCD and HV groups, and at several time points in patients with AIS or TIA. Linear regression and analysis of variance were used to analyze correlations between platelet GPIb and GPIIb/IIIa receptor numbers and demographic and clinical parameters.
RESULTS: GPIb and GPIIb/IIIa receptor numbers did not significantly differ between the AIS, CCD, and HV groups. GPIb receptor expression level correlated significantly with the magnitude of GPIIb/IIIa receptor expression and the neutrophil count. In contrast, GPIIb/IIIa receptor numbers were not associated with peripheral immune-cell sub-population counts. C-reactive protein was an independent predictor of GPIIb/IIIa (not GPIb) receptor numbers.
CONCLUSIONS: Platelet GPIb and GPIIb/IIIa receptor numbers did not distinguish between patient or control groups in this study, negating their potential use as a biomarker for predicting stroke risk.

BACKGROUND: The interactions among cells or among cells and components of the extracellular matrix, is a crucial pathophysiological process involving some molecules collectively known as adhesion molecules (CAMs). Glycoprotein IIb / IIIa receptors are only restricted to blood platelets and they bind fibrinogen and adhesion proteins such as fibronectin, vitronectin, von Willebrand factor to form cross bridges between adjacent platelets. IIb/IIIa receptor antagonists are an object of intense research activity for target therapy worldwide during the last decades. Three GPIIb/IIIa inhibitors, abciximab, tirofiban, and eptifibatide, have been approved for clinical use. Profound thrombocytopenia is an uncommon but clinically important complication of glycoprotein IIb/IIIa inhibitors.
METHODS: This case report discusses a forty-four-year-old male patient with acute coronary syndrome who underwent percutaneous coronary intervention and developed profound thrombocytopenia within 4 hours of first administration of eptifibatide.
CONCLUSIONS: This report adds another case of eptifibatide-induced thrombocytopenia to the medical literature and endorses the importance of platelet count monitoring after initiating therapy with this agent.

The management of patients with drug eluting stents (DES) who require early surgical intervention prior to the completion of antiplatelet therapy is challenging. Available literature suggests that bridging these high risk patients with glycoprotein IIb/IIIa (g2b3a) inhibitors could be efficacious in preventing stent thrombosis (Ben Morrison et al., Catheter Cardiovasc Interv 2012;79;575-582). However, this still remains to be proven in larger prospective studies. We report a case of stent thrombosis in a patient with DES planned for neurosurgery while on bridging g2b3a inhibitors therapy in the perioperative period.

Tirofiban is a glycoprotein (GP) IIb/IIIa receptor antagonist used in the treatment of acute coronary syndrome (ACS). Thrombocytopenia is a well-known complication of GPIIb/IIIa inhibitors. Life-threatening complications such as alveolar and gastrointestinal system hemorrhages may occur in the course of thrombocytopenia. Platelet count should be monitored closely, including during the first few hours of the infusion. Adverse events may be prevented by prompt discontinuation of the therapy. Herein we present two cases of profound and sudden thrombocytopenia associated with tirofiban use in the treatment of ACS together with a review of the literature.

OBJECTIVE: Drug-induced immune thrombocytopaenia is a rare, serious condition that can be triggered by numerous medications. To characterize the spectrum of drugs associated with immune thrombocytopaenia (ITP) in the Berlin Case-Control Surveillance Study (FAKOS).
METHODS: Adult hospitalized patients with new onset idiopathic, secondary or drug-induced acute ITP and hospital control patients were ascertained by active surveillance in 50 Berlin hospitals (>180 clinical departments) between 2000 and 2009. Drug exposures were obtained in a personal interview. Chronic cases were excluded in a follow-up after 6 or more months. A standardized causality assessment was conducted for each ITP patient to assess possible drug aetiology. Drug risks were quantified in a case-control design with unconditional logistic regression analysis.
RESULTS: Ninety out of 169 validated cases of acute ITP were assessed as being at least possibly drug-related (n= 85 different drugs overall, n = 30 drugs with certain or probable causality). Drugs involved in ≥ 2 cases with a probable or certain relationship were tirofiban (n = 10 cases), abciximab (n = 4), trimethoprim/sulphamethoxazole (n = 4), influenza vaccine (n = 3), and citalopram (n = 2). Pneumococcal and poliomyelitis vaccine were assessed as probably causing ITP in one case each. In the case-control analyses, significantly increased risks were observed for tirofiban, abciximab, trimethoprim/sulphamethoxazole, gentamicin, triamterene/hydrochlorothiazide, drospirenone/ethinylestradiol, and influenza vaccination.
CONCLUSIONS: Our study confirms known ITP risks for glycoprotein IIb/IIIa receptor antagonists and sulphonamides and generates signals for several other drugs and vaccines. New onset of ITP should not only direct attention to drugs as possible aetiological agents, but also to vaccines that are known to cause autoimmune phenomena.

For patients requiring surgery within their first year following coronary stent placement, maximizing the prevention of stent thrombosis with antiplatelet therapy while minimizing the risk of intraoperative bleeding has become a management challenge for cardiologists, surgeons and anesthesiologists. In this manuscript, we describe a case of a patient who received three stents (two of which were drug-eluting) and 7 months later was bridged with intravenous eptifibatide, a short-acting glycoprotein (GP) IIb/IIIa inhibitor, for 3 days prior to bronchoscopy and cervical mediastinoscopy for a suspected lung cancer. We then review the current literature for data and guidelines describing the use of short-acting GP IIb/IIIa as bridge therapy. Finally, we provide recommendations, based on our experience combined with this review, for bridge therapy in the perioperative period for patients with recent coronary stents.