Comparison of two platelet glycoprotein IIb/IIIa inhibitors, tirofiban and abciximab, for the prevention of ischemic events with percutaneous coronary revascularization

Intracoronary Versus Intravenous Low-Dose Tirofiban in Patients With ST-Elevation Myocardial Infarction: A Meta-Analysis of Randomised Controlled Trials

BACKGROUND

This meta-analysis aimed to evaluate the effects of intracoronary (IC) low-dose tirofiban versus intravenous (IV) administration on clinical outcomes in patients with ST-segment elevation myocardial infarction (STEMI).

METHODS

All published randomised controlled trials (RCTs) comparing the effects of IC low-dose tirofiban (a bolus of ≤10 ug/kg) versus IV administration in patients with STEMI were identified by searching PubMed, EMBASE, Cochrane Library, and ISI Web of Science from inception to June 2023, with no language restriction. The risk ratio (RR) with 95% confidence intervals (CI) and the weighted mean difference (WMD) with 95% CI were calculated.

RESULTS

Eleven RCTs involving 1,802 patients were included. Compared with the IV group, IC low-dose tirofiban was associated with improved major adverse cardiac events rate (RR 0.595, 95% CI 0.442-0.802; p=0.001), left ventricular ejection fraction (WMD 1.982, 95% CI 0.565-3.398; p=0.006), thrombolysis in myocardial infarction (TIMI) flow grade (RR 1.065, 95% CI 1.004-1.131; p=0.037), and TIMI myocardial perfusion grade (RR 1.194, 95% CI 1.001-1.425; p=0.049). The two groups had no significant difference in bleeding events (RR 0.952, 95% CI 0.709-1.279; p=0.745).

CONCLUSIONS

Intracoronary low-dose tirofiban administration may be a safe and effective alternative to IV administration in STEMI patients.

Glycoprotein IIb/IIIa inhibitors in the treatment of thromboembolic events related to endovascular treatment of cerebral aneurysms-systematic review and meta-analysis

BACKGROUND AND AIMS

Thromboembolism complication is considered the most common complication associated with the treatment of endovascular. This systematic review and meta-analysis aimed to assess the studies investigating the effect of glycoprotein IIb/IIIa inhibitor agents on thromboembolic complications during endovascular aneurysm coiling.

MATERIALS AND METHODS

This systematic review investigated the outcome of the use of three glycoprotein IIb/IIIa inhibitor agents (ie abciximab, tirofiban, and eptifibatide) on the thromboembolic complications during endovascular aneurysm coiling. The electronic databases of PubMed, Web of Science, Scopus, and Medline were searched up to 25 June 2021, using the keywords "Abciximab," "Tirofiban," and "Eptifibatide" incombination with "Thromboembolism Complication," "Aneurysms," and "Endovascular Aneurysm Coiling."

RESULTS

A total of 21 articles were found to be eligible and included in this review. The rates of complete and partial recanalization were estimated to be 56% and 92% in patients who underwent abciximab and tirofiban therapy, respectively. Rupture aneurysms were found in the majority of patients. In general, the mortality rate of the patients treated for thromboembolic complications during endovascular treatment of cerebral aneurysms with glycoprotein IIb/IIIa inhibitors was found to be 4.8% (CI 95%:0.027-0.067; p < .005). The average remission rate in studies investigating thromboembolism was 91% (CI 95%:0.88-0.95, I2 : 65.65/p < .001).

CONCLUSION

Based on the obtained results, a higher mean rate of complete recanalization by eptifibatide was found in studies in which abciximab or tirofiban were used, compared to other mentioned agents. Moreover, the amount of hemorrhage was reported to be less after using tirofiban rather than abciximab.

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.

Trends in Dual Antiplatelet Therapy Use for Neurointerventional Procedures for the Management of Intracranial Aneurysms

The use of periprocedural dual antiplatelet therapy (DAPT) has significantly evolved along with innovations in the endovascular management of intracranial aneurysms. Historically, aspirin and clopidogrel have been the most commonly employed regimen due to its safety and efficacy. However, recent studies highlight the importance of tailoring DAPT regimens to individual patient characteristics which may affect clopidogrel metabolism, such as genetic polymorphisms. In the present report, a systematic review of the literature was performed to determine optimal antiplatelet use with flow diverting stents, intracranial stents, intrasaccular devices, and stent-assisted coiling. Studies were analyzed for the number of aneurysms treated, DAPT regimen, and any thromboembolic complications. Based on inclusion criteria, 368 studies were selected, which revealed the increasing popularity of alternative DAPT regimens with the aforementioned devices. Thromboembolic or hemorrhagic complications associated with antiplatelet medications were similar across all medications. DAPT with ticagrelor, tirofiban, or prasugrel are effective and safe alternatives to clopidogrel and do not require enzymatic activation. Further clinical trials are needed to evaluate different antiplatelet regimens with various devices to establish highest-level evidence-based guidelines and recommendations.

Efficacy and safety of intracoronary versus intravenous tirofiban in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention: A meta-analysis of randomized controlled trials

Background

Effective antiplatelet therapy is critical for patients with ST-segment elevation myocardial infarction (STEMI) and receiving primary percutaneous coronary interventions (PPCI). Intracoronary (IC) and intravenous (IV) administration of tirofiban are commonly used during the procedure of PPCI. However, which is the better administration route of tirofiban have not been fully evaluated.

Methods

A comprehensive literature search of RCTs that comparing IC with IV tirofiban in STEMI patients undergoing PPCI was conducted, which were published as of May 7, 2022, in PubMed, Embase, Cochrane Library, Web of Science, Scopus and ClinicalTrials.gov. The primary efficacy endpoint was 30-day major adverse cardiovascular events (MACE) and the primary safety endpoint was in-hospital bleeding events.

Results

This meta-analysis included 9 trials involving 1177 patients. IC tirofiban significantly reduced the incidence of 30-day MACE (RR 0.65, 95% CI: 0.44 to 0.95, P = 0.028) and improved the rate of the thrombolysis in myocardial infarction (TIMI) grade 3 flow in high-dose (25 μg/kg) group (RR = 1.13, 95% CI: 0.99-1.30, P = 0.001), in-hospital (WMD 2.03, 95% CI: 1.03 to 3.02, P < 0.001), and 6-month left ventricular injection fraction (LVEF) (WMD 6.01, 95% CI: 5.02 to 6.99, P < 0.001) compared with IV. There was no significant difference in the incidences of in-hospital bleeding events (RR 0.96, 95% CI: 0.67 to 1.38, P = 0.82) and thrombocytopenia (RR 0.63, 95% CI: 0.26 to 1.57, P = 0.32) between the two groups.

Conclusions

IC tirofiban significantly improved the incidence of TIMI 3 in the high-dose group, in-hospital and 6-month LVEF, and reduced the 30-day MACE incidence without increasing the risk of bleeding compared with IV.

Photoinduced Vicinal 1,2-Difunctionalization of Olefins for the Synthesis of Alkyl Sulfonamides

Alkyl sulfonamides are an important class of bioactive molecules. Historical syntheses have relied on multistep sequences incorporating harsh reaction conditions. Photochemical methods have been limited to hydrosulfamoylation, installing only one substituent across an olefin. Herein, radical/polar crossover (RPC) is used to establish the first multicomponent 1,2-difunctionalization reaction incorporating a sulfonamide moiety and a second reaction partner. This protocol, exemplified on a range of olefins, utilizes various commercial sulfamoyl chlorides and organotrifluoroborates as coupling partners.

An Updated Review on Glycoprotein IIb/IIIa Inhibitors as Antiplatelet Agents: Basic and Clinical Perspectives

The glycoprotein (GP) IIb/IIIa receptor is found integrin present in platelet aggregations. GP IIb/IIIa antagonists interfere with platelet cross-linking and platelet-derived thrombus formation through the competition with fibrinogen and von Willebrand factor. Currently, three parenteral GP IIb/IIIa competitors (tirofiban, eptifibatide, and abciximab) are approved for clinical use in patients affected by percutaneous coronary interventions (PCI) in the location of acute coronary syndrome (ACS). GP IIb/IIIa antagonists have their mechanism of action in platelet aggregation prevention, distal thromboembolism, and thrombus formation, whereas the initial platelet binding to damage vascular areas is preserved. This work is aimed to provide a comprehensive review of the significance of GP IIb/IIIa inhibitors as a sort of antiplatelet agent. Their mechanism of action is based on factors that affect their efficacy. On the other hand, drugs that inhibit GP IIb/IIIa already approved by the FDA were reviewed in detail. Results from major clinical trials and regulatory practices and guidelines to deal with GP IIb/IIIa inhibitors were deeply investigated. The cardiovascular pathology and neuro-interventional surgical application of GP IIb/IIIa inhibitors as a class of antiplatelet agents were developed in detail. The therapeutic risk/benefit balance of currently available GP IIb/IIa receptor antagonists is not yet well elucidated in patients with ACS who are not clinically evaluated regularly for early cardiovascular revascularization. On the other hand, in patients who have benefited from PCI, the antiplatelet therapy intensification by the addition of a GP IIb/IIIa receptor antagonist (intravenously) may be an appropriate therapeutic strategy in reducing the occurrence of risks of thrombotic complications related to the intervention. Development of GP IIb/IIIa inhibitors with oral administration has the potential to include short-term antiplatelet benefits compared with intravenous GP IIb/IIIa inhibitors for long-term secondary preventive therapy in cardiovascular disease. But studies showed that long-term oral administration of GP IIb/IIIa receptor inhibitors has been ineffective in preventing ischemic events. Paradoxically, they have been linked to a high risk of side effects by producing prothrombotic and pro-inflammatory events.

Supplementation with omega-3 or omega-6 fatty acids attenuates platelet reactivity in postmenopausal women

Postmenopausal women are at increased risk for a cardiovascular event due to platelet hyperactivity. There is evidence suggesting that ω-3 polyunsaturated fatty acids (PUFAs) and ω-6 PUFAs have cardioprotective effects in these women. However, a mechanistic understanding of how these fatty acids regulate platelet function is unknown. In this study, we supplemented postmenopausal women with fish oil (ω-3 fatty acids) or evening primrose oil (ω-6 fatty acids) and investigated the effects on their platelet activity. The effects of fatty acid supplementation on platelet aggregation, dense granule secretion, and activation of integrin αIIbβ3 at basal levels and in response to agonist were tested in postmenopausal women following a supplementation and washout period. Supplementation with fish oil or primrose oil attenuated the thrombin receptor PAR4-induced platelet aggregation. Supplementation with ω-3 or ω-6 fatty acids decreased platelet dense granule secretion and attenuated basal levels of integrin αIIbβ3 activation. Interestingly, after the washout period following supplementation with primrose oil, platelet aggregation was similarly attenuated. Additionally, for either treatment, the observed protective effects post-supplementation on platelet dense granule secretion and basal levels of integrin activation were sustained after the washout period, suggesting a long-term shift in platelet reactivity due to fatty acid supplementation. These findings begin to elucidate the underlying mechanistic effects of ω-3 and ω-6 fatty acids on platelet reactivity in postmenopausal women. Hence, this study supports the beneficial effects of fish oil or primrose oil supplementation as a therapeutic intervention to reduce the risk of thrombotic events in postmenopausal women. https://clinicaltrials.gov/ct2/show/NCT02629497.

Antiplatelet agents for chronic kidney disease

BACKGROUND

Antiplatelet agents are widely used to prevent cardiovascular events. The risks and benefits of antiplatelet agents may be different in people with chronic kidney disease (CKD) for whom occlusive atherosclerotic events are less prevalent, and bleeding hazards might be increased. This is an update of a review first published in 2013.

OBJECTIVES

To evaluate the benefits and harms of antiplatelet agents in people with any form of CKD, including those with CKD not receiving renal replacement therapy, patients receiving any form of dialysis, and kidney transplant recipients.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 13 July 2021 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

We selected randomised controlled trials of any antiplatelet agents versus placebo or no treatment, or direct head-to-head antiplatelet agent studies in people with CKD. Studies were included if they enrolled participants with CKD, or included people in broader at-risk populations in which data for subgroups with CKD could be disaggregated.

DATA COLLECTION AND ANALYSIS

Four authors independently extracted data from primary study reports and any available supplementary information for study population, interventions, outcomes, and risks of bias. Risk ratios (RR) and 95% confidence intervals (CI) were calculated from numbers of events and numbers of participants at risk which were extracted from each included study. The reported RRs were extracted where crude event rates were not provided. Data were pooled using the random-effects model. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

We included 113 studies, enrolling 51,959 participants; 90 studies (40,597 CKD participants) compared an antiplatelet agent with placebo or no treatment, and 29 studies (11,805 CKD participants) directly compared one antiplatelet agent with another. Fifty-six new studies were added to this 2021 update. Seven studies originally excluded from the 2013 review were included, although they had a follow-up lower than two months. Random sequence generation and allocation concealment were at low risk of bias in 16 and 22 studies, respectively. Sixty-four studies reported low-risk methods for blinding of participants and investigators; outcome assessment was blinded in 41 studies. Forty-one studies were at low risk of attrition bias, 50 studies were at low risk of selective reporting bias, and 57 studies were at low risk of other potential sources of bias. Compared to placebo or no treatment, antiplatelet agents probably reduces myocardial infarction (18 studies, 15,289 participants: RR 0.88, 95% CI 0.79 to 0.99, I² = 0%; moderate certainty). Antiplatelet agents has uncertain effects on fatal or nonfatal stroke (12 studies, 10.382 participants: RR 1.01, 95% CI 0.64 to 1.59, I² = 37%; very low certainty) and may have little or no effect on death from any cause (35 studies, 18,241 participants: RR 0.94, 95 % CI 0.84 to 1.06, I² = 14%; low certainty). Antiplatelet therapy probably increases major bleeding in people with CKD and those treated with haemodialysis (HD) (29 studies, 16,194 participants: RR 1.35, 95% CI 1.10 to 1.65, I² = 12%; moderate certainty). In addition, antiplatelet therapy may increase minor bleeding in people with CKD and those treated with HD (21 studies, 13,218 participants: RR 1.55, 95% CI 1.27 to 1.90, I² = 58%; low certainty). Antiplatelet treatment may reduce early dialysis vascular access thrombosis (8 studies, 1525 participants) RR 0.52, 95% CI 0.38 to 0.70; low certainty). Antiplatelet agents may reduce doubling of serum creatinine in CKD (3 studies, 217 participants: RR 0.39, 95% CI 0.17 to 0.86, I² = 8%; low certainty). The treatment effects of antiplatelet agents on stroke, cardiovascular death, kidney failure, kidney transplant graft loss, transplant rejection, creatinine clearance, proteinuria, dialysis access failure, loss of primary unassisted patency, failure to attain suitability for dialysis, need of intervention and cardiovascular hospitalisation were uncertain. Limited data were available for direct head-to-head comparisons of antiplatelet drugs, including prasugrel, ticagrelor, different doses of clopidogrel, abciximab, defibrotide, sarpogrelate and beraprost.

AUTHORS' CONCLUSIONS

Antiplatelet agents probably reduced myocardial infarction and increased major bleeding, but do not appear to reduce all-cause and cardiovascular death among people with CKD and those treated with dialysis. The treatment effects of antiplatelet agents compared with each other are uncertain.

Glycoprotein IIb/IIIa inhibitors for the neurointerventionalist

Antiplatelet therapies are commonly used in neurointerventional procedures. However, specific guidelines for their use in these settings is lacking and it can often be difficult to balance the potential risks and benefits of these medications. Considering the continued growth and adoption of neurointerventional procedures, it is crucial to understand the properties of these agents in order to use them safely. Large-scale clinical trials are still needed to clarify many of these aspects for this emerging field. However, the existing literature already provides insight into which antiplatelet drugs are of benefit to the neurointerventionalist as well as their associated risks of ischemic and hemorrhagic complications. Hence, this review focuses on the applications of GPIIb/IIIA inhibitors to neurointerventional procedures.

Mimetics of the Arg-Gly-Asp Sequence: Synthesis and Studies of the Antiaggregative Properties

Abstract—

It is known that the Arg-Gly-Asp sequence in the fibrinogen molecule is key in binding to the receptors on the surface of platelets. We searched for the compounds which were able to inhibit the binding and synthesized the following analogs of this sequence: 2-acetoxybenzoyl-Arg-βAla-Asp, 4-piperidinecarbonyl-βAla-Asp, and 4-aminobezoyl-βAla-Asp. These compounds were shown to inhibit the platelets aggregation in a different degree. The 2-acetoxybenzoyl-Arg-βAla-Asp analog demonstrated the highest inhibitory activity. A decrease in the expression of the CD62p and CD63 markers on platelets was also found after the action of the Arg-Gly-Asp analogs, confirming the ability of these compounds to block the fibrinogen binding sites for the GP IIb/IIIa glycoprotein receptors.

Tirofiban: A Rare Cause of Thrombocytopenia in a Patient Undergoing Percutaneous Coronary Intervention

Patients admitted to the hospital can develop thrombocytopenia due to multifactorial causes. It can be pseudo-thrombocytopenia or true thrombocytopenia. Among patients admitted for chest pain, coronary angiography (CAG) is a common diagnostic test to evaluate patients for coronary artery disease (CAD). Normally, patients undergoing angiogram receive antiplatelets and anticoagulants pre-catheterization, and platelet aggregation inhibitor agents are sometimes used during and after CAG like in patients with high thrombus burden. Glycoprotein IIb/IIIa receptor inhibitors are a type of platelet antiaggregant agents that can cause severe thrombocytopenia in few cases. 

We present a case of a 68-year-old patient who came to the emergency department with inferior wall ST-segment elevation myocardial infarction and underwent angiography and had percutaneous coronary intervention (PCI) done. He was administered tirofiban during the angiogram that caused acute severe thrombocytopenia decreasing platelets count to 4000/microliter within one day. Patients' platelets gradually recovered after platelets transfusion. 

Cangrelor vs. glycoprotein IIb/IIIa inhibitors during percutaneous coronary intervention

BACKGROUND

To date, there are no real-world studies comparing cangrelor to glycoprotein IIb/IIIa inhibitors (GPI) during percutaneous coronary intervention (PCI). Thus, we performed this study to evaluate the safety and effectiveness of cangrelor compared to GPI during PCI.

METHODS

We identified patients who underwent PCI at our institution who received either cangrelor or GPI during PCI. Patients already on GPI or cangrelor prior to PCI or who received both cangrelor and GPI were excluded. Baseline demographics and clinical outcomes were extracted. Major bleeding is defined as a composite of major hematoma >4 cm, hematocrit drop >15, and gastrointestinal bleeding.

RESULTS

A total of 2072 patients received adjunctive antiplatelet therapy during PCI (cangrelor [n=478]; GPI [n=1594]). Patients' mean age was 61±12 years. Most (66%) presented with acute coronary syndrome. Patients who received cangrelor were older and had a higher percentage of acute coronary syndrome and lower baseline hematocrit in comparison with patients who received GPI. Procedural success was achieved in 94% of patients, with no difference between groups. Major bleeding events (1.7% vs. 5.1%, P=.001), any vascular complication rates, and hospital length of stay were significantly lower in the cangrelor group. In-hospital ischemic events did not differ between groups. On regression analysis, patients on cangrelor were noted to have significantly lower major bleeding events (OR 0.23; 95% CI, 0.09-0.59).

CONCLUSIONS

Balancing ischemic and bleeding risks with adjunctive antiplatelet drugs is of prime importance during PCI. Our real-world analysis shows that cangrelor is safe and effective when compared to GPI during PCI.

Efficacy and safety of abciximab versus tirofiban in addition to ticagrelor in STEMI patients undergoing primary percutaneous intervention

Platelet glycoprotein IIb/IIIa inhibitors (GPIs) have been part of the adjuvant treatment of acute coronary syndrome for years. However, real-life data regarding the efficacy and safety of GPIs under the current indications are lacking in the setting of potent platelet inhibition. The objectives were to assess the efficacy and safety of abciximab versus tirofiban in patients with ST-elevation acute myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI) and pretreated with ticagrelor, and to identify independent predictor factors of efficacy, bleeding and platelet drop. Three hundred sixty-two patients were divided by GPI administered. Clinical, laboratory, angiographic and outcome characteristics were compared. The primary objective was a composite efficacy endpoint (death from any cause, nonfatal myocardial infarction and nonfatal stroke) at 30 days. The secondary objectives were its individual components, safety (bleeding) and the impact on platelet count during hospital stay. The composite efficacy endpoint was similar in the abciximab and tirofiban groups (6.1% vs 7.3%; p = .632). There were also no differences in cardiovascular death (2.5% vs 2.4%; p = .958), nonfatal myocardial infarction (3% vs 4.3%; p = .521) and nonfatal stroke (0.5% vs 1.8%; p = .332). Tirofiban administration was associated with a higher incidence of bleeding (11.6% vs 22%; p = .008) with no differences in BARC ≥ 3b bleeding (3.6 vs 2.5%; p = .760). In STEMI patients undergoing PPCI with ticagrelor, abciximab and tirofiban had similar rates in the composite efficacy endpoint at 30 days. The 30-day bleeding rate was significantly higher in the tirofiban group. Tirofiban administration was an independent predictor of both bleeding and platelet count drop.

Discovery of a new class of integrin antibodies for fibrosis

Lung fibrosis, or the scarring of the lung, is a devastating disease with huge unmet medical need. There are limited treatment options and its prognosis is worse than most types of cancer. We previously discovered that MK-0429 is an equipotent pan-inhibitor of αv integrins that reduces proteinuria and kidney fibrosis in a preclinical model. In the present study, we further demonstrated that MK-0429 significantly inhibits fibrosis progression in a bleomycin-induced lung injury model. In search of newer integrin inhibitors for fibrosis, we characterized monoclonal antibodies discovered using Adimab's yeast display platform. We identified several potent neutralizing integrin antibodies with unique human and mouse cross-reactivity. Among these, Ab-31 blocked the binding of multiple αv integrins to their ligands with IC50s comparable to those of MK-0429. Furthermore, both MK-0429 and Ab-31 suppressed integrin-mediated cell adhesion and latent TGFβ activation. In IPF patient lung fibroblasts, TGFβ treatment induced profound αSMA expression in phenotypic imaging assays and Ab-31 demonstrated potent in vitro activity at inhibiting αSMA expression, suggesting that the integrin antibody is able to modulate TGFβ action though mechanisms beyond the inhibition of latent TGFβ activation. Together, our results highlight the potential to develop newer integrin therapeutics for the treatment of fibrotic lung diseases.

Use of Glycoprotein IIb/IIIa Inhibitors in the Modern Era of Acute Coronary Syndrome Management: A Survey of Cardiovascular Clinical Pharmacists

Evidence for the use of glycoprotein IIb/IIIa inhibitors (GPIs) in the management of acute coronary syndrome (ACS) is from the era of either limited utilization of P2Y12 inhibitors or prior the introduction of more potent P2Y12 inhibitors. This leads to divergent opinions regarding the role of these agents in contemporary practice. This study sought the opinion of cardiovascular clinical pharmacists regarding the role of GPIs in the modern of ACS management. A 13-question survey was created and distributed from June 2018 to July 2018 via the American College of Clinical Pharmacy's Cardiology Practice and Research Network e-mail listserv. The survey consisted of questions regarding the ideal use of GPIs in ACS management, preferred agent selection, and rational for selection. All results were analyzed with descriptive statistics. There were a total 69 responses of 1175 (response rate 5.9%). The majority felt there was still a role for GPI in accordance to the American College of Cardiology (ACC)/American Heart Association (AHA) guidelines for ST-segment elevation myocardial infarction (65.2%), with eptifibatide being preferred (55.1%). For non-ST-segment myocardial infraction (NSTEMI), only 49.3% felt role of GPI was in line with the ACC/AHA guidelines, but a notable number of respondents felt GPIs were only indicated in NSTEMI patients for bailout or thrombotic complications (18.8%). A majority (56.5%) felt GPIs could be used as an alternative for cangrelor when bridging. The decision to use one agent over another were efficacy data, cost, and pharmacokinetic profile.

From Snake Venom's Disintegrins and C-Type Lectins to Anti-Platelet Drugs

Snake venoms are attractive natural sources for drug discovery and development, with a number of substances either in clinical use or in research and development. These drugs were developed based on RGD-containing snake venom disintegrins, which efficiently antagonize fibrinogen activation of αIIbβ3 integrin (glycoprotein GP IIb/IIIa). Typical examples of anti-platelet drugs found in clinics are Integrilin (Eptifibatide), a heptapeptide derived from Barbourin, a protein found in the venom of the American Southeastern pygmy rattlesnake and Aggrastat (Tirofiban), a small molecule based on the structure of Echistatin, and a protein found in the venom of the saw-scaled viper. Using a similar drug discovery approach, linear and cyclic peptides containing the sequence K(R)TS derived from VP12, a C-type lectin protein found in the venom of Israeli viper venom, were used as a template to synthesize Vipegitide, a novel peptidomimetic antagonist of α2β1 integrin, with anti-platelet activity. This review focus on drug discovery of these anti-platelet agents, their indications for clinical use in acute coronary syndromes and percutaneous coronary intervention based on several clinical trials, as well as their adverse effects.

A Simple Clinical Pre-procedure Risk Model for Predicting Thrombocytopenia Associated With Periprocedural Use of Tirofiban in Patients Undergoing Percutaneous Coronary Intervention

Background: No risk model for predicting thrombocytopenia associated with periprocedural tirofiban exposure is available. The purpose of this study was to develop a simple clinical pre-procedure risk model based on pre-procedural characteristics for early prediction of thrombocytopenia before patients were exposed to tirofiban. Methods: The series included 1862 patients who underwent percutaneous coronary intervention with tirofiban exposure. Baseline demographic and clinical characteristics were collected from the hospital information system on admission. The earliest pro-procedural platelets within 72 h were used to evaluate the thrombocytopenia incidence. Risk factors associated with thrombocytopenia in patients with tirofiban exposure were investigated by univariable and multivariable analyses. Locally weighted scatterplot smoothing procedure was used to identify the cut points for the numeric variables. The discriminatory power of the scoring system was assessed with the receiver operating characteristic (ROC) curve analysis. Results: The occurrence of thrombocytopenia was 4.02% (75 of 1862), 4.01% (56 of 1396), and 4.08% (19 of 466) in the overall, developmental, and validation data sets, respectively. The risk score was developed based on five independent predictors: age ≥65y, white blood cell ≥12 × 10⁹/L, diabetes mellitus, congestive heart failure, and chronic kidney disease. This tool was well calibrated (Hosmer Lemeshow χ² = 6.914; P = 0.546) and good discrimination was well obtained in validation data set (C-statistic, 0.82). Conclusion: The clinical pre-procedure risk model is a simple and accurate tool for early identification of high-risk patients of thrombocytopenia before tirofiban exposure, allowing for timely and appropriate intervention.

Platelet Signaling and Disease: Targeted Therapy for Thrombosis and Other Related Diseases

Platelets are essential for clotting in the blood and maintenance of normal hemostasis. Under pathologic conditions such as atherosclerosis, vascular injury often results in hyperactive platelet activation, resulting in occlusive thrombus formation, myocardial infarction, and stroke. Recent work in the field has elucidated a number of platelet functions unique from that of maintaining hemostasis, including regulation of tumor growth and metastasis, inflammation, infection, and immune response. Traditional therapeutic targets for inhibiting platelet activation have primarily been limited to cyclooxygenase-1, integrin αIIbβ3, and the P2Y12 receptor. Recently identified signaling pathways regulating platelet function have made it possible to develop novel approaches for pharmacological intervention in the blood to limit platelet reactivity. In this review, we cover the newly discovered roles for platelets as well as their role in hemostasis and thrombosis. These new roles for platelets lend importance to the development of new therapies targeted to the platelet. Additionally, we highlight the promising receptor and enzymatic targets that may further decrease platelet activation and help to address the myriad of pathologic conditions now known to involve platelets without significant effects on hemostasis.

Real-world evidence: How pragmatic are randomized controlled trials labeled as pragmatic?

INTRODUCTION

Pragmatic randomized controlled trials (RCTs) mimic usual clinical practice and they are critical to inform decision-making by patients, clinicians and policy-makers in real-world settings. Pragmatic RCTs assess effectiveness of available medicines, while explanatory RCTs assess efficacy of investigational medicines. Explanatory and pragmatic are the extremes of a continuum. This debate article seeks to evaluate and provide recommendation on how to characterize pragmatic RCTs in light of the current landscape of RCTs. It is supported by findings from a PubMed search conducted in August 2017, which retrieved 615 RCTs self-labeled in their titles as "pragmatic" or "naturalistic". We focused on 89 of these trials that assessed medicines (drugs or biologics).

DISCUSSION

36% of these 89 trials were placebo-controlled, performed before licensing of the medicine, or done in a single-center. In our opinion, such RCTs overtly deviate from usual care and pragmatism. It follows, that the use of the term 'pragmatic' to describe them, conveys a misleading message to patients and clinicians. Furthermore, many other trials among the 615 coined as 'pragmatic' and assessing other types of intervention are plausibly not very pragmatic; however, this is impossible for a reader to tell without access to the full protocol and insider knowledge of the trial conduct. The degree of pragmatism should be evaluated by the trial investigators themselves using the PRECIS-2 tool, a tool that comprises 9 domains, each scored from 1 (very explanatory) to 5 (very pragmatic).

CONCLUSIONS

To allow for a more appropriate characterization of the degree of pragmatism in clinical research, submissions of RCTs to funders, research ethics committees and to peer-reviewed journals should include a PRECIS-2 tool assessment done by the trial investigators. Clarity and accuracy on the extent to which a RCT is pragmatic will help understand how much it is relevant to real-world practice.

Force-activatable biosensor enables single platelet force mapping directly by fluorescence imaging

Integrin-transmitted cellular forces are critical for platelet adhesion, activation, aggregation and contraction during hemostasis and thrombosis. Measuring and mapping single platelet forces are desired in both research and clinical applications. Conventional force-to-strain based cell traction force microscopies have low resolution which is not ideal for cellular force mapping in small platelets. To enable platelet force mapping with submicron resolution, we developed a force-activatable biosensor named integrative tension sensor (ITS) which directly converts molecular tensions to fluorescent signals, therefore enabling cellular force mapping directly by fluorescence imaging. With ITS, we mapped cellular forces in single platelets at 0.4µm resolution. We found that platelet force distribution has strong polarization which is sensitive to treatment with the anti-platelet drug tirofiban, suggesting that the ITS force map can report anti-platelet drug efficacy. The ITS also calibrated integrin molecular tensions in platelets and revealed two distinct tension levels: 12-54 piconewton (nominal values) tensions generated during platelet adhesion and tensions above 54 piconewton generated during platelet contraction. Overall, the ITS is a powerful biosensor for the study of platelet mechanobiology, and holds great potential in antithrombotic drug development and assessing platelet activity in health and disease.

The comparative safety of abciximab versus eptifibatide in patients on dialysis undergoing percutaneous coronary intervention: Insights from the Blue Cross Blue Shield of Michigan Cardiovascular Consortium (BMC2)

OBJECTIVES

We sought to evaluate the patterns of use and outcomes associated with eptifibatide and abciximab administration among dialysis patients who underwent percutaneous coronary intervention (PCI).

BACKGROUND

Contraindicated medications are frequently administered to dialysis patients undergoing PCI often resulting in adverse outcomes. Eptifibatide is a glycoprotein IIb/IIIa inhibitor that is often used during PCI and is contraindicated in dialysis.

METHODS

We included dialysis patients who underwent PCI from January 2010 to September 2015 at 47 hospitals in Michigan. We compared outcomes between patients who received eptifibatide compared with abciximab. Both groups required concurrent treatment with unfractionated heparin only. In-hospital outcomes included repeat PCI, bleeding, major bleeding, need for transfusion, and death. Optimal full matching was used to adjust for non-random drug administration.

RESULTS

Of 177 963 patients who underwent PCI, 4303 (2.4%) were on dialysis. Among those, 384 (8.9%) received eptifibatide and 100 (2.3%) received abciximab. Prior to matching, patients who received eptifibatide had higher pre-procedural hemoglobin levels (11.3 g/dL vs. 10.7 g/dL; P < 0.001) and less frequently had a history of myocardial infarction (36.5% vs. 52.0%; P = 0.005). After matching, there were no significant differences in in-hospital outcomes between eptifibatide and abciximab including transfusion (aOR: 1.15; 95%CI: 0.55-2.40; P = 0.70), bleeding (1.47; 0.64-3.40; P = 0.36), major bleeding (4.68; 0.42-52.3; P = 0.21), repeat PCI (0.38; 0.03-4.23; P = 0.43), and death (1.53; 0.2-9.05; P = 0.64).

CONCLUSIONS

Despite being contraindicated in dialysis, eptifibatide was used approximately 3.5 times more frequently than abciximab among dialysis patients undergoing PCI but was associated with similar in-hospital outcomes.

Intra-Arterial Use of Abciximab in Thromboembolic Complications Associated with Cerebral Aneurysm Coiling: The London Ontario Experience

BACKGROUND

Experience with intra-arterial infusion of abciximab for the treatment of endovascular thrombotic complications is limited to short case series. Our objective is to evaluate the safety and effectiveness of this drug for the treatment of thromboembolic complications during aneurysm coiling and to determine the risk factors.

METHODS

From an aneurysm coiling database, patients treated with intra-arterial abciximab after having thrombotic complications during the coiling procedure were selected for analysis. Complications after using abciximab were categorized as hemorrhage, distal migration of the thrombus, and aneurysm recanalization.

RESULTS

Fourteen coiling patients sustained a thromboembolic complication and were treated using intra-arterial infusion of abciximab and were subjected to further analysis. The age range was 48-76 years. Three patients were male. Seven patients had subarachnoid hemorrhage. Only complete recanalization was associated with clinical improvement, but this occurred in only 4 patients (28.5%). Partial or complete recanalization occurred in 13 patients (93%). Eight patients (57%) had complications derived from the infusion. Three patients had aneurysm recanalization, 3 patients had distal migration of the thrombus and 1 patient had a hemorrhagic complication. Eight patients demonstrated acute infarcts related to the occluded vessel, whereas 7 patients made a good functional recovery.

CONCLUSION

Successful recanalization of a vessel occluded by thrombus formation during aneurysm coiling using abciximab (Reopro) infusion is less than optimal. There are risks related to abciximab, including bleeding and aneurysm recanalization.

Antiplatelet Therapy in Acute Coronary Syndrome

Antiplatelet agents have for decades been used to improve outcomes in patients with acute coronary syndromes and have become increasingly valued, not only for their antithrombotic properties but also for their anti-inflammatory effects. The drug class continues to evolve as novel agents with increasingly efficacious antiplatelet actions are identified. This review will discuss antiplatelet agents, including aspirin, the P2Y₁₂ receptor antagonists and the glycoprotein IIb/IIIa inhibitors, that are currently used to treat patients with unstable angina and myocardial infarction, focusing on their pharmacological properties and the clinical evidence supporting their use.

The role of Glycoprotein IIb/IIIa inhibitors in acute coronary syndromes and the interference with anemia

The role played by glycoprotein (GP) IIb/IIIa inhibitors (GPI) has continuously evolved until the most recent Guidelines whereby they were stepped down from class I to class II recommendation for treating acute coronary syndromes (ACS). GPI compete with a wider use of ADP inhibitors and novel anticoagulant drugs although GPI use has greatly narrowed. However, GPI may still have a role. Several criteria were proposed to define post-PCI anemia which is strictly related to bleeding and transfusion. In ACS, it should be important to define anemia in comparative terms versus baseline levels: ≥ 15% of red blood cell decrease should be a practical cut-off value. If one wishes to concentrate on hemoglobin (Hb), a≥2g/dl Hb decrease from baseline should be considered. It is important to recognize post-PCI anemia in the setting of ACS. There are sub-populations exposed to short-term hemorrhagic and/or long-term ischemic risks. Ischemic and hemorrhagic risks need to be carefully evaluated along with thrombocytopenia and its prognostic significance in order to put all these blood and rheological parameters into a clinically oriented perspective on which therapeutical decisions should be based. Definition of high risk procedures (complexity, angiographic characteristics and patient's risk profile, regardless whether STEMI or NSTEMI) may help selecting GPI. There are positive elements in GPI use: efficacy, rapid onset and reversibility of action, absence of pharmacogenomic variability, pharmacoeconomic considerations and the possibility of intracoronary administration. All these elements should be evaluated when selecting these agents for therapeutics.

Effect of Preprocedural Thrombocytopenia on Prognosis After Percutaneous Coronary Intervention

OBJECTIVE

To assess early and late outcomes, including bleeding, in patients with thrombocytopenia undergoing percutaneous coronary intervention (PCI).

PATIENTS AND METHODS

We performed a retrospective single-center study of patients with preprocedural thrombocytopenia (platelet count ≤100,000/μL; n=204) undergoing PCI between 2003 and 2015. Inhospital and late outcomes were compared with those of a matched control group without thrombocytopenia (n=1281).

RESULTS

The most common causes of thrombocytopenia were liver disease, immune-mediated disease, and hematologic malignant neoplasms. Inhospital bleeding events after PCI were similar in patients with thrombocytopenia and matched controls (24 of 146 [16.4%] vs 179 of 1281 [14.0%]; P=.40) and were largely classified as minor using the Bleeding Academic Research Consortium (BARC) classification (89% BARC 1 or 2). There was no significant difference in inhospital death (4 of 146 [2.7%] vs 71 of 1281 [2.0%]; P=.56), but patients with thrombocytopenia had higher rates of platelet and red blood cell transfusion (18 of 146 [12.3%] vs 93 of 1281 [7.2%]; P=.05). During long-term follow-up, Kaplan-Meier estimated rates of bleeding events (BARC ≥2) were higher for thrombocytopenia (at 5 years, 7.9% vs 3.6%; P=.03). Patients with thrombocytopenia had a similar risk of long-term cardiac mortality, but significantly higher rates of noncardiac mortality (at 5 years, 28% vs 21%; P=.02).

CONCLUSION

This study suggests that short-term outcomes after PCI in patients with thrombocytopenia were favorable. On long-term follow-up, thrombocytopenia was associated with a higher risk of long-term noncardiac mortality and bleeding.

Gene mutations of platelet glycoproteins and response to tirofiban in acute coronary syndrome

CONTEXT AND OBJECTIVES

Glycoprotein inhibitors (abciximab, eptifibatide and tirofiban) are used in patients with unstable angina and non-ST-segment elevation myocardial infarction before percutaneous coronary intervention. Of these, tirofiban is the least effective. We hypothesized that the response to tirofiban might be associated with glycoprotein gene mutations.

DESIGN AND SETTING

Prospective study at Emergency Unit, Heart Institute (InCor), University of São Paulo.

METHOD

Intrahospital evolution and platelet aggregation in response to tirofiban were analyzed in relation to four glycoprotein mutations in 50 patients indicated for percutaneous coronary intervention: 17 (34%) with unstable angina and 33 (66%) with non-ST-segment elevation myocardial infarction. Platelet aggregation was analyzed using the Born method. Blood samples were obtained before and one hour after tirofiban infusion. Glycoproteins Ia (807C/T ), Ib (Thr/Met) , IIb (Ile/Ser ) and IIIa (PIA ) were the mutations selected.

RESULTS

Hypertension, dyslipidemia, diabetes, smoking, previous coronary artery disease and stroke were similar between the groups. Mutant glycoprotein IIIa genotypes had lower platelet aggregation before tirofiban administration than that of the wild genotype (41.0% ± 22.1% versus 55.9% ± 20.8%; P = 0.035). Mutant glycoprotein IIIa genotypes correlated moderately with lower platelet inhibition (r = -0.31; P = 0.030). After tirofiban administration, platelet glycoprotein Ia, Ib, IIb and IIIa mutations did not influence the degree of inhibition of platelet aggregation or intrahospital mortality.

CONCLUSIONS

Mutations of glycoproteins Ia, Ib, IIb and IIIa did not influence platelet aggregation in response to tirofiban in patients with unstable angina and non-ST-segment elevation myocardial infarction.

The Impact of Thrombocytopenia on Outcome in Patients with Acute Coronary Syndromes: A Single Center Retrospective Study

Background. In acute coronary syndromes (ACS), treated by combined antithrombotic therapy and percutaneous coronary interventions (PCI), thrombocytopenia may occur. Our aim was to evaluate predictors and the impact of thrombocytopenia on mortality in high-risk ACS patients. Methods. We retrospectively evaluated high-risk ACS patients. Thrombocytopenia was defined as platelet count <140.000/mL or a drop in platelet count of >50% during in-hospital stay. We compared demographic, laboratory, clinical, and mortality data between nonthrombocytopenic and thrombocytopenic ACS patients and evaluated independent predictors of thrombocytopenia. Results. In 371 ACS patients, thrombocytopenia was observed in 21.3%. Thrombocytopenic patients were significantly older and, less likely treated by PCIs (72.1% versus 89.7%, p < 0.001) and combined antithrombotic therapy, with increased incidence of in-hospital complications and the use of additional treatments, but with increased mortality at 30 days (27.8% versus 10.2%, p < 0.001) and 6 months (35.4% versus 13.6%, p < 0.001) when compared to nonthrombocytopenic patients. The use of antibiotics, transfusions, insertion of intra-aortic balloon pump (IABP), and prior stroke independently predicted thrombocytopenia. Conclusions. Thrombocytopenia, observed in about 20% of high-risk ACS patients, was associated significantly with in-hospital complications and mortality. Predictors of thrombocytopenia were the use of antibiotics, transfusions, insertion of IABP, and prior stroke.

The effects of tirofiban infusion on clinical and angiographic outcomes of patients with STEMI undergoing primary PCI

Objective:

The present study was designed to determine the effects of tirofiban (Tiro) infusion on angiographic measures, ST-segment resolution, and clinical outcomes in patients with STEMI undergoing PCI. Glycoprotein (GP) IIb/IIIa inhibitors are beneficial in ST-segment elevation myocardial infarction (STEMI) patients undergoing percutaneous coronary intervention (PCI), while the most effective timing of administration is still under investigation.

Methods:

A total of 1242 patients (83.0% males, mean (standard deviation; SD) age: 54.7 (10.9) years) with STEMI who underwent primary PCI were included in this retrospective non-randomized study in four groups, composed of no tirofiban infusion [Tiro (-); n=248], tirofiban infusion before PCI (pre-Tiro; n=720), tirofiban infusion during PCI (peri-Tiro; n=50), and tirofiban infusion after PCI (post-Tiro; n=224). In all Tiro (+) patients, bolus administration of Tiro (10 pg/kg) was followed by infusion (0.15 pg/kg/min) for a mean (SD) duration of 22.4±6.8 hours.

Results:

The pre-PCI Tiro group was associated with the highest percentage of patients with TIMI 3 flow (99.4%; p<0.001), the lowest corrected TIMI frame count [21(18-23.4); p<0.001], the highest percentage of patients with >75% ST-segment resolution (78.1%; p<0.001), and the lowest rate of in-hospital sudden cardiac death and in-hospital all-cause mortality (3.2%, p<0.05, 3.3%, p=0.01). Major bleeding was reported in 18 (1.8%) patients who received tirofiban.

Conclusion:

Use of standard-dose bolus tirofiban in addition to aspirin, high-dose clopidogrel, and unfractionated heparin prior to primary PCI significantly improves myocardial reperfusion, ST-segment resolution, in-hospital mortality rate, and in-hospital sudden cardiac death in patients with STEMI with no increased risk of major bleeding.

Long-term outcomes associated with hospital acquired thrombocytopenia among patients with non-ST-segment elevation acute coronary syndrome

BACKGROUND

Acquired thrombocytopenia after a non-ST-segment-elevation-acute coronary syndrome (NSTE-ACS) has been associated with increased in-hospital mortality and hemorrhagic complications, but longer term outcomes are unclear. We examined the association between thrombocytopenia and long-term outcomes after accounting for thrombocytopenia severity and discharge medication use.

METHODS

Data from 7,435 NSTE-ACS patients enrolled in the SYNERGY trial were analyzed. Severe thrombocytopenia was defined as a nadir platelet count <100 × 10(9)/L or a ≥ 50% drop from baseline. Mild thrombocytopenia was defined as a nadir platelet count between 100 and 149 × 10(9)/L with a <50% drop from baseline. The primary outcomes of interest were in-hospital GUSTO moderate-severe bleeding and 1-year mortality.

RESULTS

Overall, 675 patients (9.1%) developed mild thrombocytopenia and 139 patients (1.9%) developed severe thrombocytopenia. In-hospital bleeding risks were higher in patients with mild (7.7%, adjusted HR 1.63, 95% CI 1.16-2.29) or severe (28.2%, adjusted HR 6.93, 95% CI 4.55-10.56) thrombocytopenia than in patients without thrombocytopenia (5.2%). One-year mortality rates were 6.5%, 8.1%, and 28.1% among patients with no, mild, and severe thrombocytopenia, respectively (log rank P < 0.001) but only severe thrombocytopenia remained significantly associated with increased mortality after adjustment: HR 4.07, 95% CI 2.86-5.78. Patients who developed severe thrombocytopenia were less likely to be discharged on guideline-recommended antiplatelet therapy. The relationship between severe thrombocytopenia and mortality was attenuated by but persisted after adjusting for discharge medication use (HR 2.83, 95% CI 1.49-5.38).

CONCLUSIONS

Thrombocytopenia occurs commonly during the course of NSTE-ACS care; even mild decreases are associated with clinically meaningful bleeding. Patients who developed severe thrombocytopenia were less likely to be discharged on guideline-recommended antiplatelet therapy; this may contribute to their higher associated long-term mortality.

A comprehensive acute coronary syndrome algorithm for centers with percutaneous coronary intervention capability

A comprehensive acute coronary syndrome (ACS) protocol was developed to improve the quality of care for patients admitted with definite or probable ACS. These protocols were constructed to streamline the practice for diverse clinicians who care for ACS patients across a variety of clinical settings. They are applicable in the emergency department, the cardiac catheterization laboratory, and the inpatient settings for hospitals with primary percutaneous coronary intervention capability. These protocols standardized the care by selecting the best therapy for each clinical scenario based on available established guidelines to insure the safest and highest value (quality/cost) medical care.

Tirofiban in acute coronary syndromes

Acute coronary syndromes represent a major health problem in terms of incidence and mortality. Intracoronary platelet-rich thrombi may develop in response to plaque rupture, and are involved in the pathogenesis of all acute coronary syndromes. The glycoprotein IIb/IIIa receptor, a platelet surface integrin, plays a key role in platelet aggregation once it has been activated by specific ligands. The development of glycoprotein IIb/IIIa inhibitors has revolutionized the management of acute coronary syndromes. Tirofiban is one of three parenteral glycoprotein IIb/IIIa inhibitors in clinical use, and many trials have demonstrated its clinical efficacy and low rate of adverse effects in patients with non-ST-segment elevation acute coronary syndrome. This article reviews the data concerning its use in the clinical settings of acute coronary syndromes and percutaneous coronary angioplasty, and discusses its benefits in different treatment strategies and in association with other drugs. In particular, the role of early, upstream tirofiban coupled with early aggressive revascularization in the management of high-risk non-ST-segment elevation acute coronary syndromes is emphasized.

Development of glycoprotein IIb–IIIa antagonists: translation of pharmacodynamic effects into clinical benefit

This article will review the development of glycoprotein IIb-IIIa antagonists, with particular emphasis on the characteristics and pharmacodynamic studies of each agent that is available for clinical use. Abciximab is a Fab fragment of the 7E3 antibody that has high affinity and a slow rate of dissociation from glycoprotein IIb-IIIa. In contrast, the small molecules eptifibatide and tirofiban, have a much more rapid rate of dissociation, with an off time of 10 to 15 s. Accordingly, the circulating pool of abciximab is predominantly associated with platelets, whereas maintenance of a consistent concentration of tirofiban and eptifibatide in the blood is critical in order to achieve and sustain their inhibitory effects. The affinity of abciximab and tirofiban for glycoprotein IIb-IIIa are substantially greater than that of eptifibatide, necessitating maintenance of greater molar concentrations of eptifibatide in blood in order to achieve effective inhibition of the binding of fibrinogen to the activated conformer of glycoprotein IIb-IIIa.

Effects of Upstream Administration of Tirofiban Before Percutaneous Coronary Intervention on Spontaneous Reperfusion and Clinical Outcomes in Acute ST-Segment Elevation Myocardial Infarction

We assessed the effects of upstream administration of the glycoprotein IIb/IIIa inhibitor tirofiban before percutaneous coronary intervention (PCI) on spontaneous reperfusion (SR) of infarct-related artery (IRA) and the clinical outcomes in patients with ST-segment elevation myocardial infarction (STEMI). The incidence of SR of the IRA was significantly higher in the tirofiban group than in the no-tirofiban group (141 [36.5%] vs 21 [17.2%], P < .001). By multivariate logistic regression analysis, use of tirofiban (odds ratio 2.32, 95% confidence interval 1.25-4.31, P = .008) independently predicted the occurrence of SR. Kaplan-Meier survival analysis demonstrated that major adverse cardiovascular event-free survival was significantly higher in patients treated with tirofiban than in patients without tirofiban at 30-day (log rank = 11.65, P = .001) and 90-day follow-up (log rank = 16.79, P < .001). Upstream administration of tirofiban is significantly associated with increased SR of the IRA and favorable clinical prognosis in patients undergoing PCI for STEMI.

Platelet glycoprotein IIb/IIIa blockers during percutaneous coronary intervention and as the initial medical treatment of non-ST segment elevation acute coronary syndromes

BACKGROUND

During percutaneous coronary intervention (PCI), and in non-ST segment elevation acute coronary syndromes (NSTEACS), the risk of acute vessel occlusion by thrombosis is high. Glycoprotein IIb/IIIa blockers strongly inhibit platelet aggregation and may prevent mortality and myocardial infarction. This is an update of a Cochrane review first published in 2001, and previously updated in 2007 and 2010.

OBJECTIVES

To assess the efficacy and safety effects of glycoprotein IIb/IIIa blockers when administered during PCI, and as initial medical treatment in patients with NSTEACS.

SEARCH METHODS

We updated the searches of the Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochrane Library (Issue 12, 2012), MEDLINE (OVID, 1946 to January Week 1 2013) and EMBASE (OVID, 1947 to Week 1 2013) on 11 January 2013.

SELECTION CRITERIA

Randomised controlled trials comparing intravenous IIb/IIIa blockers with placebo or usual care.

DATA COLLECTION AND ANALYSIS

Two authors independently selected studies for inclusion, assessed trial quality and extracted data. We collected major bleeding as adverse effect information from the trials. We used odds ratios (OR) and 95% confidence intervals (CI) for effect measures.

MAIN RESULTS

Sixty trials involving 66,689 patients were included. During PCI (48 trials with 33,513 participants) glycoprotein IIb/IIIa blockers decreased all-cause mortality at 30 days (OR 0.79, 95% CI 0.64 to 0.97) but not at six months (OR 0.90, 95% CI 0.77 to 1.05). All-cause death or myocardial infarction was decreased both at 30 days (OR 0.66, 95% CI 0.60 to 0.72) and at six months (OR 0.75, 95% CI 0.64 to 0.86), although severe bleeding was increased (OR 1.39, 95% CI 1.21 to 1.61; absolute risk increase (ARI) 8.0 per 1000). The efficacy results were homogeneous for every endpoint according to the clinical condition of the patients, but were less marked for patients pre-treated with clopidogrel, especially in patients without acute coronary syndromes.As initial medical treatment of NSTEACS (12 trials with 33,176 participants), IIb/IIIa blockers did not decrease mortality at 30 days (OR 0.90, 95% CI 0.79 to 1.02) or at six months (OR 1.00, 95% CI 0.87 to 1.15), but slightly decreased death or myocardial infarction at 30 days (OR 0.91, 95% CI 0.85 to 0.98) and at six months (OR 0.88, 95% CI 0.81 to 0.96), although severe bleeding was increased (OR 1.29, 95% CI 1.14 to 1.45; ARI 1.4 per 1000).

AUTHORS' CONCLUSIONS

When administered during PCI, intravenous glycoprotein IIb/IIIa blockers reduce the risk of all-cause death at 30 days but not at six months, and reduce the risk of death or myocardial infarction at 30 days and at six months, at a price of an increase in the risk of severe bleeding. The efficacy effects are homogeneous but are less marked in patients pre-treated with clopidogrel where they seem to be effective only in patients with acute coronary syndromes. When administered as initial medical treatment in patients with NSTEACS, these agents do not reduce mortality although they slightly reduce the risk of death or myocardial infarction.