Impact of clinical syndrome acuity on the differential response to 2 glycoprotein IIb/IIIa inhibitors in patients undergoing coronary stenting: the TARGET Trial

Review: The pathogenesis of type 2 diabetes and cardiovascular disease

Type 2 diabetes mellitus is increasing in prevalence, and is a potent risk factor for the development of atherosclerotic vascular disease and increased risk of adverse cardiovascular events. Approximately 15—25% of patients presenting with ischaemic heart disease have a history of diabetes mellitus. This cohort of patients continues to be at heightened short and long-term risk. This review highlights the many proposed biological drivers that likely play a deterministic role in the cardiovascular outcome of patients with type 2 diabetes mellitus.

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.

Balance of Ischemia and Bleeding in Selecting an Antithrombotic Regimen

Complications after percutaneous coronary intervention (PCI) are of 2 types: ischemic and bleeding. This article provides strategies to individualize pharmacologic regimens after PCI based on periprocedural risk assessment. A practical method to assess whether a patient is at risk for ischemic or bleeding complications is the use of risk scores. Patients at a low risk of bleeding benefit from aggressive antithrombotic therapy. Patients at a high risk of bleeding benefit from selective use of antithrombotic agents. As a large number of antithrombotic agents are currently available, individualization of the antithrombotic drug regimes should be considered in every patient.

Stenting in Acute STEMI Intervention

Stenting in acute myocardial infarction (AMI) has the benefits of achieving acute optimal angiographic results and correcting residual dissection to decrease the incidence of restenosis and reocclusion. Studies have shown that percutaneous transluminal coronary angioplasty for primary treatment after AMI is superior to thrombolytic therapy regarding the restoration of normal coronary blood flow. Coronary stenting improves initial success rates, decreases the incidence of abrupt closure, and is associated with a reduced rate of restenosis. In the presence of thrombus-containing lesions, coronary stenting constitutes an effective therapeutic strategy, either after failure of initial angioplasty or electively as the primary procedure.

Contemporary use of glycoprotein IIb/IIIa inhibitors

Platelet glycoprotein IIb/IIIa inhibitors (GPI) are antithrombotic agents preventing the binding of fibrinogen to GP IIb/IIIa receptors. Thus, GPI interfere with interplatelet bridging mediated by fibrinogen. Currently, three generic GPI with different antithrombotic properties are available for intravenous administration: abciximab, eptifibatide, and tirofiban. The development of oral GPI was abandoned, whereas intravenous GPI were introduced in various clinical settings during the 1990s, yielding substantial benefit in the treatment of acute coronary syndromes, particularly during percutaneous coronary interventions. Results of the many randomised trials evidenced the efficacy of this drug class, though these trials were conducted prior to the emergence of modern oral antiplatelet therapy with efficient P2Y(12) inhibitors. Subsequent trials failed to consolidate the strongly favourable impression of GPI, and indications for their use have been more restricted in recent years. Nonetheless, GPI may still be beneficial during coronary interventions among high-risk patients including acute ST-elevation and non-ST-elevation myocardial infarctions, particularly in the absence of adequate pretreatment with oral antiplatelet drugs or when direct thrombin inhibitors are not utilised. Intracoronary GPI administration has been suggested as adjunctive therapy during primary percutaneous coronary intervention, and the results of larger ongoing trials are expected to elucidate its clinical potential. The present review outlines the key milestones of GPI development and provides an up-to-date overview of the clinical applicability of these drugs in the era of refined coronary stenting, potent antithrombotic drugs, and novel thrombin inhibiting agents.

Comparison of catheterization laboratory initiated abciximab and eptifibatide during percutaneous coronary intervention in acute coronary syndromes (an ACUITY substudy)

Abciximab and eptifibatide have been shown to reduce ischemic complications compared with heparin alone in patients with acute coronary syndromes who undergo percutaneous coronary intervention. Whether 1 agent is safer and/or more effective has not been prospectively examined. The aim of this study was to assess the outcomes related to downstream glycoprotein IIb/IIIa inhibitor treatment selection during percutaneous coronary intervention in 2,211 patients with moderate and high-risk acute coronary syndromes in the prospective multicenter Acute Catheterization and Urgent Intervention Triage Strategy (ACUITY) trial. The protocol permitted operator selection of abciximab (n = 835) or eptifibatide (n = 1,376) for routine use in the trial. Multivariate and propensity-based adjustments were used to assess the independent association of glycoprotein IIb/IIIa inhibitor treatment selection with prespecified study end points. Compared to patients receiving eptifibatide, those administered abciximab were older, more likely to be enrolled outside of North America, more frequently had biomarker elevations and ST-segment deviation, but had fewer baseline cardiac risk factors and previous revascularization procedures. After multivariate propensity-based adjustment, abciximab was independently associated with significantly fewer net clinical adverse events (odds ratio 0.61, 95% confidence interval 0.42 to 0.90, p = 0.01), mediated by composite ischemia (odds ratio 0.61, 95% confidence interval 0.38 to 0.98, p = 0.04) and major bleeding (odds ratio 0.58, 95% confidence interval 0.34 to 1.00, p = 0.051). In conclusion, in this prespecified but nonrandomized comparison in patients with acute coronary syndromes who underwent percutaneous coronary intervention with catheterization laboratory initiation of glycoprotein IIb/IIIa inhibitors, the use of abciximab rather than eptifibatide was associated with improved clinical outcomes at 30 days. These findings should be viewed as exploratory in light of the nonrandomized and heterogeneous nature of the comparator groups and significant potential for residual confounding.

Boosting platelet inhibition in poor responder to aspirin and clopidogrel undergoing percutaneous coronary intervention: role of tirofiban

Nowadays, aspirin (acetylsalicylic acid) and clopidogrel form the cornerstone in prevention of cardiovascular events and their clinical effectiveness has been well established. The thienopyridine clopidogrel is a prodrug that, after hepatic metabolization, strongly inhibits adenosine diphosphate-induced platelet aggregation. Aspirin is a non-steroidal anti-inflammatory drug that exerts its anti-platelet action through the irreversible acetylation of platelet cyclooxygenase (COX)-1, blocking thromboxane A2 production. However, despite dual-antiplatelet therapy, some patients still develop recurrent cardiovascular ischemic events. Many studies have clearly showed that a marked variability exists in the responsiveness to aspirin and clopidogrel, being the poor responder patients at higher risk of short (peri-procedural) and long-term ischemic complications. In particular, these patients showed a major recurrence of myocardial infarction and, after stent implantation, of stent thrombosis. The mechanisms of aspirin and clopidogrel poor response are numerous and not fully elucidated, and are likely multifactorial (eg, genetic polymorphisms, elevated baseline platelet reactivity, drug interaction). How to improve the short- and long-term outcome of these patients is currently unknown. Recently published and ongoing clinical trials are evaluating different strategies for the acute and chronic treatments (eg, reload of clopidogrel, double clopidogrel maintenance dose, switching to prasugrel). In this paper, we reviewed all available evidence on aspirin and clopidogrel resistance and focused our attention on tirofiban, a glycoprotein IIb/IIIa inhibitor that may be used to obtain a better platelet inhibition in poor responder patients during the acute phase and in particular during percutaneous coronary intervention.

Cangrelor: a novel P2Y12 receptor antagonist

Antiplatelet therapy is critical in the prevention of thrombotic complications of acute coronary syndrome and percutaneous coronary interventions. Current antiplatelet agents (aspirin, clopidogrel and glycoprotein IIb/IIIa antagonists) have demonstrated the capacity to reduce major adverse cardiac events. However, these agents have limitations that compromise their clinical utility. The platelet P2Y12 receptor plays a central role in platelet function and is a focus in the development of antiplatelet therapies. Cangrelor is a potent, competitive inhibitor of the P2Y12 receptor that is administered by intravenous infusion and rapidly achieves near complete inhibition of ADP-induced platelet aggregation. This investigational drug has been studied for use during coronary procedures and the management of patients experiencing acute coronary syndrome and is undergoing evaluation for use in the prevention of perioperative stent thrombosis.

Re-evaluating risk factors for periprocedural complications during percutaneous coronary intervention in patients with unstable angina/non-ST-elevation myocardial infarction: who may benefit from more intensive antiplatelet therapy?

PURPOSE OF REVIEW

Controversy regarding the optimal antiplatelet/antithrombotic regimen indicates a need to re-evaluate the place of these agents in treating patients with unstable angina/non-ST-segment elevation myocardial infarction undergoing percutaneous coronary intervention.

RECENT FINDINGS

Although clinical trial data suggest that glycoprotein IIb-IIIa inhibition benefits moderate-risk to high-risk patients, recent studies question the use of intensive antiplatelet therapy in lower risk patients. The resultant shift towards less intensive alternative regimens raises questions about identifying patients in whom an alternative strategy is preferable. The concept of risk stratification for coronary intervention has evolved from lesion-based categorization to include clinical factors, for example, elevated levels of cardiac troponin.

SUMMARY

Risk factors for periprocedural complications during percutaneous coronary intervention can be divided into anatomic (unprotected left main stenting, bifurcation lesions, and diffuse disease) and clinical (older age, diabetes, renal disease, left ventricular function, recent myocardial damage, and female sex) factors. These may interact additively or synergistically, increasing the likelihood of complications in patients who might otherwise have been considered at low risk. We need to reconsider, therefore, how we identify appropriate options and, hopefully, optimize clinical outcomes. This review evaluates risk factors for periprocedural complications in an effort to determine patients who may benefit most from intensive antiplatelet regimens.

Effectiveness and safety of reduced-dose enoxaparin in non-ST-segment elevation acute coronary syndrome followed by antiplatelet therapy alone for percutaneous coronary intervention

Adjunctive pharmacotherapy for stabilizing patients with acute coronary syndrome/non-ST-segment elevation myocardial infarction (ACS/NSTEMI) and for subsequent percutaneous coronary intervention (PCI) includes a combination of anticoagulant and antiplatelet agents. However, all anticoagulants have been shown to paradoxically activate platelets and induce other prothrombotic activities, increase bleeding, and/or cause thrombocytopenia. A single-center experience of 1,400 consecutive patients presenting with ACS/NSTEMI managed using decreased-dose anticoagulation (enoxaparin) and dual-antiplatelet therapy (aspirin and clopidogrel) followed by triple-antiplatelet therapy (aspirin, clopidogrel, and eptifibatide) alone, without additional anticoagulation, during subsequent PCI was retrospectively analyzed. Patients received a median of 3 doses of enoxaparin at a mean dose of 0.51 mg/kg. The final dose was administered 10.8 hours (mean) before PCI. Medical management "failed" in 8 patients (0.6%), and each required emergency PCI. The overall technical success rate was 99.8%. One major adverse clinical event (0.1%) occurred within 24 hours after PCI. Non-Q-wave myocardial infarction occurred in 1.8% of patients, major and minor bleeding complications, in 0.1% and 2.1%, respectively, and thrombocytopenia in 1.3%. Five additional major adverse clinical events (0.4%) occurred within 30 days after PCI, none involving target vessel thrombosis. In conclusion, for patients with ACS/NSTEMI, reduced-dose enoxaparin combined with dual-antiplatelet therapy followed by triple-antiplatelet therapy alone (without additional anticoagulation) during subsequent PCI appears safe and may prove efficacious.

Monitoring antiplatelet therapy during peripheral vascular and coronary interventions

Platelets play a central role in the initiation and propagation of thrombus formation. The use of antiplatelet and antithrombotic medications during peripheral vascular and coronary interventions helps reduce the likelihood of intravascular thrombus formation and adverse ischemic events. As formation of intravascular thrombus and subacute stent thrombosis are thrombin- and platelet-mediated phenomenon, achieving optimal activated clotting time and platelet inhibition (PI) during the interventional procedure is critical. However, as a quick and easy measure of platelet function has previously not been available in the interventional laboratory, cardiovascular interventions are routinely performed after administration of oral or intravenous antiplatelet agents without evaluating platelet function. Recently, point-of-care rapid platelet function assays have become available that allow quick and reproducible measure of platelet function in the interventional laboratory after administration of aspirin, thienopyridines, and glycoprotein IIb/IIIa inhibitors. Though PI can now be routinely measured during vascular interventions, considerable inconsistencies exist in the management of patients based on these results. We present an algorithm for the management of antiplatelet therapy during cardiovascular interventions based on rapid evaluation of platelet function in the interventional laboratory.

Evaluation on the safety and efficacy of tirofiban in the treatment of acute coronary syndrome

To evaluate the safety and efficacy of tirofiban, a specific inhibitor of the platelet glycoprotein llb/llla receptor, in the treatment of unstable angina and myocardial infarction without persistent ST elevation (acute coronary syndrome, ACS), a total of 200 patients were randomly assigned to a heparin group and a tirofiban+heparin group on double-blind basis and the treatment effects of the two protocols on ACS were compared when the patients of both groups were taking aspirin at the same time. The composite primary end-point events consisted of death, myocardial infarction, or refractory ischemia. Our results showed that the frequency of the composite primary end point events in 30 days was lower in tirofiban+heparin group as compared with that of heparin group (13.9% vs 29.3 %, P=0.010). The rates of the other composite end point events in the tirofiban+heparin group were also lower than those in the heparin group in 4.5 days and in 30 days. Bleeding complication occurred in 7.0% of the patients receiving heparin alone and in 12.7% of the patients receiving tirofiban and heparin in combination (P=0.1717). The study showed that the incidence of ischemic events in patients with ACS receiving tirofiban+heparin was lower when compared with that of patients who received only heparin and aspirin, suggesting that tirofiban might be of special value in the treatment of ACS.

Thrombus predicts ischemic complications during percutaneous coronary intervention in saphenous vein grafts: Results from TARGET (do tirofiban and reopro give similar efficacy trial?)

BACKGROUND

Saphenous vein graft (SVG) percutaneous coronary intervention (PCI) carries a high risk of ischemic complications. However, there are scant recent data to identify which SVG lesions carry particularly high risk in recent years. We studied demographic and angiographic factors associated with ischemic complications after SVG PCI without distal protection in the TARGET (do tirofiban and reopro give similar efficacy trial?) study.

METHODS

TARGET was a multicenter double-dummy, double-blinded study randomizing 4,809 PCI patients to tirofiban or abciximab. Of these, 254 patients underwent PCI involving an SVG lesion. The primary endpoint of this analysis was major adverse cardiac events (MACEs) at 30 days, including death, nonfatal myocardial infarction (MI), and urgent target vessel revascularization.

RESULTS

No demographic characteristic was associated with 30-day MACE. Lesion length > 20 mm (odds ratio [OR] = 2.7, P = 0.03), thrombus (OR = 3.9, P = 0.003), eccentricity (P = 0.001), thrombolysis in myocardial infarction flow < 3 post-procedure (OR = 5.6, P = 0.037), and >1 target lesion (OR = 2.5, P = 0.035) were univariate variables associated with 30-day MACE. Multivariate analysis associated only thrombus (OR = 3.8, P = 0.015) with 30-day MACE. No difference in outcomes was noted between patients receiving abciximab and tirofiban. SVG patients had lesser angiographic success (95.6% vs. 98%, P = 0.04) and increased 30-day Q-wave MI (2.5% vs. 0.9%, P = 0.039) compared with non-SVG patients, but a similar incidence of death (0% vs. 0.4%), non-Q-MI (5.9% vs. 4.5%), and target vessel revascularization (0.5% vs. 1%).

CONCLUSION

In the era of routine stenting and GpIIb/IIIa inhibitors, thrombus is the angiographic characteristic most closely associated with adverse outcomes of SVG PCI.

Impact of the Degree of Peri-Interventional Platelet Inhibition After Loading With Clopidogrel on Early Clinical Outcome of Elective Coronary Stent Placement

OBJECTIVES

Our prospective study tested the hypothesis that the 30-day clinical outcome of elective percutaneous catheter intervention (PCI) differs between strata defined by quartiles of platelet aggregation after loading with 600 mg clopidogrel.

BACKGROUND

Platelet responses after loading with clopidogrel are highly variable. The impact of this variability on the peri-interventional risk of patients undergoing PCI has not been investigated prospectively.

METHODS

Our study included 802 consecutive patients undergoing elective coronary stent placement. Before PCI, patients received a loading dose of 600 mg clopidogrel followed by 75 mg daily. Primary end point was the 30-day composite of death, myocardial infarction, and target lesion revascularization (major adverse cardiac events [MACE]). Platelet aggregation was assessed immediately before PCI by optical aggregometry (5 micromol/l adenosine diphosphate).

RESULTS

During 30-day follow-up, 15 patients (1.9%) incurred MACE (3 deaths, 8 myocardial infarctions, 8 target lesion revascularizations). Quartiles of platelet aggregation were <4%, 4% to 14%, 15% to 32%, and >32%. Thirty-day MACE differed significantly (p = 0.034) between quartiles of platelet aggregation. It was 0.5% in the first quartile, 0.5% in the second, 3.1% in the third, and 3.5% in the fourth. Platelet aggregation above the median carried a 6.7-fold risk (95% confidence interval 1.52 to 29.41; p = 0.003) of 30-day MACE. Multivariable logistic regression analysis, including pertinent covariables, confirmed platelet aggregation as a significant independent predictor of 30-day MACE (adjusted odds ratio per 10% increase in platelet aggregation 1.32, 95% confidence interval 1.04 to 1.61; p = 0.026).

CONCLUSIONS

The level of platelet aggregation immediately before elective coronary stenting in patients pre-treated with a high loading dose of clopidogrel is correlated with early outcome after the procedure.

The Role of Risk Stratification in the Decision to Provide Upstream Versus Selective Glycoprotein IIb/IIIa Inhibitors for Acute Coronary Syndromes

OBJECTIVES

We endeavored to determine under what conditions a strategy of upstream use of small molecule platelet glycoprotein (GP) IIb/IIIa inhibitors for all acute coronary syndromes (ACS) patients is cost effective compared to that of selective use of abciximab in only those patients requiring percutaneous coronary intervention (PCI).

BACKGROUND

Small molecule GP IIb/IIIa inhibitors have shown benefit in ACS, but abciximab, the more expensive GP IIb/IIIa inhibitor, may be more effective during PCI. However, abciximab does not have proven efficacy in medical management. No prior study has attempted to balance these competing benefits.

METHODS

A decision analysis was performed to examine two strategies: 1) treat all ACS patients upstream with a small molecule GP IIb/IIIa inhibitor and continue through medical management and PCI, if performed; or 2) wait, and selectively use abciximab only in patients who ultimately undergo PCI. Applicable randomized controlled trial data were used for the principal analysis.

RESULTS

The strategy of upstream use of a small molecule GP IIb/IIIa inhibitor was superior to selective use, and economically acceptable, with a cost-effectiveness ratio of 18,000 dollars per year of life gained. The superiority of the upstream use strategy persisted over the majority of sensitivity analyses. When stratified by risk according to Thrombolysis in Myocardial Infarction risk score, a strategy of upstream use was only cost effective in those patients with moderate or high risk.

CONCLUSIONS

Upstream use of small molecule GP IIb/IIIa inhibition in ACS patients with moderate or high risk for cardiovascular events is a cost-effective approach that should be considered in this subset of patients.

The relationship of obesity to ischemic outcomes following coronary stent placement in contemporary practice

OBJECTIVES

We analyzed the relationship of obesity, determined by body mass index (BMI), to short- and long-term outcomes in the TARGET trial.

BACKGROUND

: Previous studies have conflicting findings regarding the relationship of BMI to outcomes following percutaneous coronary intervention (PCI).

METHODS

The TARGET trial studied the use of glycoprotein (GP) IIb/IIIa inhibition in patients undergoing planned coronary stent placement.

RESULTS

Eighty-one percent of all patients were overweight (BMI > 25), 36% were obese (BMI > 30), and United States patients were more frequently obese (38.7% vs. 25.8%, P < 0.001). Obese patients had a similar 30-day ischemic event rate compared with nonobese patients, but less major bleeding (0.4% vs. 1.1%, P = 0.013). Six-month death and myocardial infarction rates were similar in obese and nonobese patients. There was a J-shaped relationship between 6-month target vessel revascularization (TVR) and BMI with the lowest incidence of TVR at BMI 27.5. Six-month TVR was higher in the morbidly (BMI > 35) obese (12.4% vs 8.7%, P < 0.05). In extremely (BMI > 32) obese patients, this relationship was more significant (TVR 11.3% vs. 8.5%, P = 0.007), particularly in patients <65 years of age (TVR 12.3% vs. 8.4%, P = 0.003).

CONCLUSION

The majority of patients undergoing PCI are overweight, especially in the United States. Extreme obesity is associated with a significant increase in TVR following intent-to-stent PCI, especially in patients <65 years of age. With routine use of GP IIb/IIIa inhibitors, other long- and short-term ischemic events are similar in obese and nonobese patients. However, obese patients have significantly less major bleeding.

Tirofiban for the treatment of ischaemic stroke

Tirofiban is one of three glycoprotein IIb/IIIa receptor antagonists approved by the US FDA, beside abciximab and eptifibatide. The approval of tirofiban covers conservative treatment of myocardial infarction and unstable angina, as well as percutaneous coronary intervention, for which treatment with tirofiban is recommended in moderate-to-high-risk patients. The efficacy of glycoprotein IIb/IIIa antagonists in myocardial infarction indicated that these agents may also be helpful in the treatment of acute ischaemic stroke. Although experimental data are lacking, observational studies are promising. In recent years, increasing effort in studying glycoprotein IIb/IIIa antagonists has been made, mostly for treatment with abciximab. However, there is one Phase II trial that investigated treatment with tirofiban.

Peri-procedural myocardial injury: 2005 update

During the past three decades, percutaneous coronary intervention has become one of the cardinal treatment strategies for stenotic coronary artery disease. Technical advances, including the introduction of new devices such as stents, have expanded the interventional capabilities of balloon angioplasty. At the same time, there has been a decline in the rate of major adverse cardiac events, including Q-wave acute myocardial infarction, emergency coronary artery bypass grafting, and cardiac death. Despite these advances, the incidence of post-procedural cardiac marker elevation has not substantially decreased since the first serial assessment 20 years ago. As of now, these post-procedural cardiac marker elevations are considered to represent peri-procedural myocardial injury (PMI) with worse long-term outcome potential. Recent progress has been made for the identification of two main PMI patterns, one near the intervention site (proximal type, PMI type I) and one in the distal perfusion territory of the treated coronary artery (distal type, PMI type II) as well as for preventive strategies. Integrating these new developments into the wealth of clinical information on this topic, this review aims at giving a current perspective on the entity of PMI.

Effects of tirofiban plus clopidogrel versus clopidogrel plus provisional abciximab on biomarkers of myocardial necrosis in patients with non-ST-elevation acute coronary syndromes treated with early aggressive approach. Results of the CLOpidogrel, upstream TIrofiban, in cath Lab Downstream Abciximab (CLOTILDA) study

BACKGROUND

In non-ST-elevation acute coronary syndromes (NSTE-ACS), a strong correlation between adverse clinical events and peak values of myocardial necrosis markers has been found. In this study, we evaluated whether the adjunctive treatment with upstream tirofiban reduces the peak levels of cardiac troponin I and creatine kinase-MB (CK-MB) fraction in patients with NSTE-ACS undergoing early invasive strategy and pretreated with aspirin, heparin, and clopidogrel.

METHODS

A total of 300 patients were randomized to receive tirofiban (group 1) or not (group 2). Serial marker samples were collected before and after coronary angiography in all cases and after percutaneous coronary intervention (PCI) when performed.

RESULTS

Between the 2 groups, no differences were observed in clinical and angiographic findings. Percutaneous coronary intervention was globally performed in 198 patients (66%). Of 99 group 2 patients, 26 (26%) received abciximab just before PCI. No significant differences between the 2 groups were observed with regard to cardiac troponin I and CK-MB values at admission and at 6, 12, and 24 hours thereafter; peak values before coronary angiography; and peak values of index event. In addition, the cumulative biomarkers release of the index event was similar between the 2 groups. Major bleeding rate was 2% in group 1 and 1% in group 2 (P = not significant). Composite incidence of death, myocardial infarction, or rehospitalization for ACS at 30 days was 9% in group 1 and 10% in group 2.

CONCLUSIONS

In patients with NSTE-ACS undergoing early invasive strategy, the adjunctive administration of upstream tirofiban did not reduce the peak values and the cumulative release of myocardial necrosis markers, compared with aspirin, heparin, and clopidogrel given on admission and associated with selective use of abciximab just before PCI.

Mortality at 1 year for the direct comparison of tirofiban and abciximab during percutaneous coronary revascularization: do tirofiban and ReoPro give similar efficacy outcomes at trial 1-year follow-up

AIMS

Compared with placebo, abciximab has been associated with mortality reduction at late follow-up. The TARGET trial was performed to test whether tirofiban and abciximab provide similar efficacy outcomes among patients undergoing non-emergent, stent-based percutaneous coronary intervention. We report here the 1-year mortality of the study population.

METHODS AND RESULTS

In 18 countries at 149 hospitals, 4,809 patients undergoing elective or urgent stent implantation were randomly assigned a bolus and infusion of tirofiban or abciximab. Ischaemic events were assessed at 30 days and 6 months and mortality was assessed at 1 year. We previously reported that abciximab was superior to tirofiban considering the composite rate of death or myocardial infarction at 30 days among all patients and at 6 months among those with an acute coronary syndrome (ACS). At 1-year follow-up death occurred in 46 (1.9%) patients who received tirofiban and 42 (1.7%) patients who received abciximab (hazard ratio 1.10, 95% CI 0.72-1.67; P=0.660). Mortality rates for patients with ACS were 2.3% with tirofiban vs. 2.2% with abciximab (hazard ratio 1.03, 95% CI 0.64-1.67; P=0.897) and those without ACS were 1.4 vs. 1.0% (hazard ratio 1.32, 95% CI 0.56-3.13; P=0.530).

CONCLUSION

At 1 year, tirofiban provided a similar level of survival benefit compared with abciximab.

Characterization of myocardial infarction as an end point in two large trials of acute coronary syndromes

Myocardial infarction (MI) is a key component of composite end points in trials that evaluate new therapies in non-ST-segment elevation acute coronary syndromes. Types of MI events in these trials have not been well characterized. A similar clinical-events classification process adjudicated all suspected MI end points in the PURSUIT and PARAGON B trials. All MI end points were classified as nonprocedural, related to percutaneous coronary intervention, or related to coronary artery bypass grafting. A total of 16,173 patients was enrolled in the 2 trials, and 1,802 MI end points occurred during a 30-day follow-up. Nearly 66% of MI end points were not related to percutaneous coronary intervention or coronary artery bypass grafting. Patients who had MI compared with those who did not had higher 30-day mortality rates (13.6% vs 2.3%, p <0.001) and 6-month mortality rates (18.4% vs 4.4%, p <0.001). Patients who had been randomized to glycoprotein IIb/IIIa inhibition showed trends toward fewer MI events regardless of type. Two-thirds of MI end points in 2 large trials of acute coronary syndrome were not related to procedure. All MI types were associated with worse short- and long-term outcomes. Characterization of the type of MI provides an opportunity for more informed interpretation of clinical trial results and improved planning for future trials.

Outcomes with the paclitaxel-eluting stent in patients with acute coronary syndromes

OBJECTIVES

We sought to investigate the outcomes of paclitaxel-eluting stent implantation in patients with unstable angina or non-ST-segment elevation myocardial infarction undergoing percutaneous coronary intervention (PCI).

BACKGROUND

Whether the paclitaxel-eluting stent is safe and effective in patients with acute coronary syndromes (ACS) is unknown.

METHODS

In the TAXUS-IV trial, 1,314 patients with stable or unstable ischemic syndromes undergoing PCI were randomized to treatment with either the slow-release, polymer-based, paclitaxel-eluting TAXUS stent or a bare-metal EXPRESS stent (Boston Scientific Corp., Natick, Massachusetts). The results were stratified by the acuity of the presenting clinical syndrome.

RESULTS

Acute coronary syndromes were present in 450 patients (34.2%), 237 of whom were assigned to paclitaxel-eluting stents and 213 to bare-metal stents. The baseline and procedural characteristics were well matched between the groups. Clinical outcomes at 30 days were similar with both stents. At one-year follow-up, patients with ACS assigned to the paclitaxel-eluting stent compared to the control stent had strikingly lower rates of target lesion revascularization (TLR) (3.9% vs. 16.0%, p < 0.0001) and major adverse cardiac events (11.1 vs. 21.7%, p = 0.002). By multivariate analysis, ACS was an independent predictor of in-stent restenosis in the cohort treated with bare-metal stents (hazard ratio [HR] = 2.03 [95% confidence interval (CI) 1.05 to 3.92], p = 0.035), while among patients randomized to the paclitaxel-eluting stents, ACS was an independent predictor of freedom from restenosis (HR = 0.27 [95% CI 0.08 to 0.97], p = 0.04).

CONCLUSIONS

The use of the paclitaxel-eluting TAXUS stent was safe in patients with unstable ischemic syndromes, and was associated with marked reduction of ischemia-driven TLR and adverse cardiac events at one year.

Guidelines for percutaneous coronary interventions. The Task Force for Percutaneous Coronary Interventions of the European Society of Cardiology

In patients with stable CAD, PCI can be considered a valuable initial mode of revascularization in all patients with objective large ischaemia in the presence of almost every lesion subset, with only one exception: chronic total occlusions that cannot be crossed. In early studies, there was a small survival advantage with CABG surgery compared with PCI without stenting. The addition of stents and newer adjunctive medications improved the outcome for PCI. The decision to recommend PCI or CABG surgery will be guided by technical improvements in cardiology or surgery, local expertise, and patients' preference. However, until proved otherwise, PCI should be used only with reservation in diabetics with multi-vessel disease and in patients with unprotected left main stenosis. The use of drug-eluting stents might change this situation. Patients presenting with NSTE-ACS (UA or NSTEMI) have to be stratified first for their risk of acute thrombotic complications. A clear benefit from early angiography (<48 h) and, when needed, PCI or CABG surgery has been reported only in the high-risk groups. Deferral of intervention does not improve outcome. Routine stenting is recommended on the basis of the predictability of the result and its immediate safety. In patients with STEMI, primary PCI should be the treatment of choice in patients presenting in a hospital with PCI facility and an experienced team. Patients with contra-indications to thrombolysis should be immediately transferred for primary PCI, because this might be their only chance for quickly opening the coronary artery. In cardiogenic shock, emergency PCI for complete revascularization may be life-saving and should be considered at an early stage. Compared with thrombolysis, randomized trials that transferred the patients for primary PCI to a 'heart attack centre' observed a better clinical outcome, despite transport times leading to a significantly longer delay between randomization and start of the treatment. The superiority of primary PCI over thrombolysis seems to be especially clinically relevant for the time interval between 3 and 12 h after onset of chest pain or other symptoms on the basis of its superior preservation of myocardium. Furthermore, with increasing time to presentation, major-adverse-cardiac-event rates increase after thrombolysis, but appear to remain relatively stable after primary PCI. Within the first 3 h after onset of chest pain or other symptoms, both reperfusion strategies seem equally effective in reducing infarct size and mortality. Therefore, thrombolysis is still a viable alternative to primary PCI, if it can be delivered within 3 h after onset of chest pain or other symptoms. Primary PCI compared with thrombolysis significantly reduced stroke. Overall, we prefer primary PCI over thrombolysis in the first 3 h of chest pain to prevent stroke, and in patients presenting 3-12 h after the onset of chest pain, to salvage myocardium and also to prevent stroke. At the moment, there is no evidence to recommend facilitated PCI. Rescue PCI is recommended, if thrombolysis failed within 45-60 min after starting the administration. After successful thrombolysis, the use of routine coronary angiography within 24 h and PCI, if applicable, is recommended even in asymptomatic patients without demonstrable ischaemia to improve patients' outcome. If a PCI centre is not available within 24 h, patients who have received successful thrombolysis with evidence of spontaneous or inducible ischaemia before discharge should be referred to coronary angiography and revascularized accordingly--independent of 'maximal' medical therapy.

Elective percutaneous coronary intervention using broad-spectrum antiplatelet therapy (eptifibatide, clopidogrel, and aspirin) alone, without scheduled unfractionated heparin or other antithrombin therapy

BACKGROUND

Adjunctive pharmacotherapy during percutaneous coronary intervention (PCI) has historically consisted of a regimen of antiplatelet agents accompanied by an antithrombin agent, typically unfractionated heparin. Paradoxically, unfractionated heparin may activate platelets, induce other pro-thrombotic activities, increase bleeding complications, and cause thrombocytopenia. To optimize patient care and avoid the potential risks of unfractionated heparin in patients undergoing elective PCI, one of the authors began to use adjunctive pharmacotherapy consisting of broad-spectrum antiplatelet therapy alone, without scheduled unfractionated heparin or other antithrombin therapy.

METHODS

Five hundred consecutive patients undergoing scheduled, elective PCI (stent deployment, cutting balloon atherotomy, conventional balloon angioplasty, or high-speed rotational atherectomy) received adjunctive pharmacotherapy consisting of eptifibatide, clopidogrel, and aspirin.

RESULTS

The technical success rate was 100%. During the first 24 hours, there were no major adverse clinical events. Non-Q-wave myocardial infarction occurred in 1.6% of patients, major and minor bleeding complications in 0.2% and 0.6%, respectively, and thrombocytopenia in 0.6%. During the first 30 days, there was 1 (0.2%) major adverse clinical event.

CONCLUSIONS

For elective PCI, adjunctive pharmacotherapy consisting of broad-spectrum antiplatelet therapy alone, without scheduled unfractionated heparin or other antithrombin therapy, appears to be safe and may prove to be efficacious.

Practical approach to the diagnosis and management of thrombocytopenia associated with tirofiban treatment

Anti-GPIIb/IIIa associated thrombocytopenia has been reported in most large trials, but very little data is available regarding tirofiban. We report three cases of thrombocytopenia, most likely attributed to tirofiban (two moderate and one severe). For each patient, laboratory investigation has allowed us to exclude another cause of thrombocytopenia, particularly heparin-induced thrombocytopenia. Platelet count recovery could be earlier with tirofiban than with abciximab. Some suggestions are proposed for practical management of these patients with persistent thrombotic risk, who are sometimes candidates for cardiopulmonary bypass surgery.

Glycoprotein IIb-IIIa antagonists in non-ST elevation acute coronary syndromes and percutaneous interventions: from pharmacology to individual patient's therapy: Part 2: When and how to use various agents

Patients with high-risk characteristics admitted for non-ST elevation acute coronary syndromes benefit from an early invasive treatment, and in this case glycoprotein (GP) IIb/IIIa inhibitors appear effective in improving prognosis. There is however an ongoing debate on which of the currently available agents is the best in patients who are candidates for percutaneous coronary interventions. The dispute revolves on the optimal level of inhibition of platelet function and on whether the benefit is retained in the presence of pretreatment with thienopyridines. Especially the additional value of GP IIb/IIIa inhibition on top of an aggressive antithrombotic therapy (including aspirin, heparins, and clopidogrel) requires further clarification. Here we propose an algorithm for the practical use of available GPIIb/IIIa antagonists in relation with the patient's clinical presentation and concomitant use of other drugs and devices.

The additive value of tirofiban administered with the high-dose bolus in the prevention of ischemic complications during high-risk coronary angioplasty

OBJECTIVES

We sought to determine the safety and efficacy of high-dose bolus (HDB) tirofiban in high-risk patients undergoing percutaneous coronary intervention (PCI).

BACKGROUND

The use of HDB tirofiban in the catheterization laboratory is controversial. In particular, in patients with acute coronary syndromes undergoing PCI, there is no evidence that tirofiban administered in the catheterization laboratory is superior to heparin alone. This finding probably reflects the suboptimal platelet inhibition when tirofiban is employed at RESTORE (Randomized Efficacy Study of Tirofiban for Outcomes and Restenosis) regimen.

METHODS

A total of 202 patients (mean age 69 +/- 8 years; 137 males [68%]) undergoing high-risk PCI, pretreated with thienopyridines, were consecutively randomized to HDB tirofiban (25 microg/kg/3 min, and infusion of 0.15 microg/kg/min for 24 to 48 h) or placebo immediately before the procedure and then followed for a median time of 185 days (range 45 to 324 days) for the occurrence of the primary composite end point of death, myocardial infarction, target vessel revascularization (TVR), and bailout use of glycoprotein (GP) IIb/IIIa inhibitors.

RESULTS

The cumulative incidence of the primary end point was 35% and 20% in placebo and HDB tirofiban groups, respectively (hazard ratio 0.51, 95% confidence interval 0.29 to 0.88; p = 0.01). This difference was mainly due to the reduction of myocardial infarction and bailout use of GP IIb/IIIa inhibitors, with no significant effect on TVR or death. The safety profile did not differ between tirofiban and placebo.

CONCLUSIONS

The use of tirofiban, when administered at HDB, is safe and significantly reduces the incidence of ischemic/thrombotic complications during high-risk PCI.

National economic impact of tirofiban for unstable angina and myocardial infarction without ST elevation; example from the United Kingdom

BACKGROUND

Acute coronary syndromes without ST elevation are a major health and economic burden. Treatments such as glycoprotein IIb/IIIa antagonists like tirofiban reduce the risk of complications but the cost impact of these agents including cost offsets of avoiding complications are needed particularly in Europe.

METHODS

We used treatment patterns from the Prospective Registry of Acute Ischemic Syndromes in the UK, risk reductions derived from the PRISM-PLUS trial and cost estimates from the CHKS database to estimate the impact of tirofiban on PRAIS-UK patients with and without complications and subgroups at higher risk of complications. These subgroups (and proportions) were patients: (1) aged 60 or over with abnormal electrocardiograms (58%), (2) with ST depression or bundle branch block on admission (30%) and (3) with ST depression, bundle branch block or MI on admission (37%).

RESULTS

Total cost of care in the UK at 6 months for the estimated 87339 acute coronary syndromes admissions annually was pound 213 million, which would increase by pound 33 million (15.7%) if tirofiban were given to all patients, avoiding 2422 complications at a mean cost per event avoided of pound 13388. Among the subgroups, the mean cost per event avoided ranges from pound 10856 for subgroup 1 to pound 5953 for subgroup 3. Treating the latter subgroup, would avoid 1977 events at a cost of pound 12 million (5.5%).

CONCLUSION

The use of tirofiban in the UK to treat acute coronary syndromes patients without ST elevation provides an important therapeutic advantage at modest proportional increase in cost, particularly if targeted to higher risk subgroups as recommended in the European guidelines.

Use of GPIIb/IIIa inhibitors in cardiovascular medicine

The GPIIb/IIIa inhibitors were the first clinically used anti-integrin therapeutics. They opened the gate to a rapidly developing area of anti-integrin targeting as a therapeutic approach to many diseases. The use of GPIIb/IIIa inhibitors in interventional cardiology is widespread and still increasing, as is the number of percutaneous coronary interventions. There seems to be a class effect of GPIIb/IIIa inhibitors in percutaneous coronary intervention, but there are major differences in the pharmacokinetics and pharmacodynamics of these agents. Currently clinically approved for parenteral use are the Fab fragment abciximab (ReoPro, Lilly) and the small-molecule GPIIb/IIIa inhibitors eptifibatide (Integrilin, Millennium/Schering-Plough) and tirofiban (Aggrastat, Merck). This review focuses on the different pharmacological properties of these agents and summarizes present and future therapeutic use of GPIIb/IIIa inhibitors in cardiovascular and other vascular diseases.

Effect of Adjunctive Tirofiban Therapy on Angiographic and Clinical Outcomes in Patients With ST-segment Elevated Acute Myocardial Infarction Undergoing Primary Stenting

The benefit of primary percutaneous coronary intervention is limited by a 5% to 20% incidence of suboptimal epicardial coronary blood (< or = TIMI-2 flow). Recently, data has demonstrated that when administered in conjunction with primary stenting for the treatment of acute myocardial infarction (AMI), abciximab improves the success rate of the stenting procedure and provides additional clinical benefits. But data on a combination of tirofiban and primary stenting for treatment of ST-segment elevated (ST-se) AMI is unknown. Between May 1999 and September 2000, primary stenting without adjunctive tirofiban therapy was performed in 136 consecutive patients (control group) with ST-se AMI. Between January 2001 and May 2002, we routinely administered tirofiban to 133 consecutive patients (study group) with ST-se AMI before they underwent primary stenting. The angiographic and clinical outcomes of both groups were compared in a chronologically consecutive manner. The overall mortality rate was significantly higher in patients with failed (< or = TIMI-2 flow) than in patients with successful (TIMI-3) reperfusion (20.0% vs 3.5%, P < 0.0001). Univariate analysis demonstrated that there were no significant differences in the successful reperfusion (85.7% vs 84.6%, P = 0.84) or 30-day combined end points - death, recurrent ischemia or reinfarction (8.3% vs 11.0%, P = 0.59) between study and control group patients. Clinical variables were used to statistically analyze potential risk factors for unsuccessful reperfusion (< or = TIMI-2 flow) in the study group patients. Multiple stepwise logistic regression analysis demonstrated that the reference lumen diameter (RLD) of the infarct-related artery (IRA) > or = 3.5 mm (P = 0.0004) and the lesion length of the obstruction > or = 20.0 mm (P = 0.018) were the significant independent predictors of failed normalized coronary blood flow. There were no significant differences in the restenotic rate of IRA (29.2% vs 30.8%, P = 0.9) or mortality rate (1.6% vs 1.6%, P = 1.0) at six-month follow-up. In conclusion, our study demonstrates that primary stenting with adjunctive tirofiban therapy in ST-se AMI did not provide additional benefits in short-term and intermediate-term angiographic and clinical outcomes compared to conventional primary stenting.

Prediction of outcome after percutaneous coronary intervention for the acute coronary syndrome

BACKGROUND

The seven-component Thrombolysis In Myocardial Infarction (TIMI) score has been used to risk stratify, and to guide the medical management of, patients with unstable angina or non-ST-elevation myocardial infarction. We assessed the usefulness of the risk score in predicting in-hospital and 30-day outcomes in such patients who were undergoing percutaneous coronary intervention.

METHODS

Using the TIMI score, 2501 patients with unstable angina or non-ST-elevation myocardial infarction were divided into low-risk (zero to two risk factors; n = 974), intermediate-risk (three to four risk factors; n = 1339), and high-risk (five to seven risk factors; n = 188) groups, and outcomes were compared.

RESULTS

Angiographic/clinical success and the rate of minor procedural events were similar among the three groups. A higher TIMI risk score was associated with more cardiac comorbid conditions and more complicated angiographic lesions: longer lesions (P = 0.0009), more thrombotic lesions (P = 0.03), more multivessel disease (P <0.0001), and more American College of Cardiology/American Heart Association type B2/C lesions (P = 0.05). Although the risk score did not predict interventional technical success or intraprocedural complications, a high score was associated with prolonged hospital stay, higher postprocedural peak troponin levels, and 30-day major adverse cardiac events. Stepwise logistic regression showed that in conjunction with lesion length and patient sex, a high score was an independent predictor of 30-day major adverse cardiac events (odds ratio = 2.3; 95% confidence interval: 1.1 to 4.1; C statistic = 0.62).

CONCLUSION

Although a higher TIMI risk score in patients with unstable angina or non-ST-elevation myocardial infarction who were undergoing percutaneous coronary intervention correlated with adverse clinical outcome, the score alone cannot be used to guide diagnostic or therapeutic strategies.

Safety of same-day-discharge radial percutaneous coronary intervention: a retrospective study

BACKGROUND

The safety and feasibility of same-day discharge percutaneous coronary intervention (PCI) is still controversial.

METHODS

Patients (n = 943) had same-day discharge radial PCI between April 1998 and March 2001 in our hospital. Patients were contacted and asked whether they had entry site complications or a repeat angiogram and/or PCI within 24 hours and 1 month after the procedure.

RESULTS

At the time the study was conducted, 811 patients responded, 38 patients had died, and 94 were alive but refused to participate or it was impossible to contact them; 27 patients (2.8%) visited their doctor and/or the hospital within 24 hours after discharge because of entry site complications, and 38 patients (4.0%) visited within 1 month. However, none of the patients had major access site complications or needed to be admitted to the hospital. Within 24 hours from discharge 17 patients (2%) reported chest pain, and only 1 (0.1%) required a repeat angiogram, which did not show target vessel occlusion. During the first month, 94 patients (11.5%) reported chest pain, 11 (1.3%) underwent a repeat angiogram, out of which 4 had subacute vessel closure; 2 of the 132 patients that we could not contact had subacute stent thrombosis within 1 month and died.

CONCLUSIONS

None of the patients having same-day discharge radial PCI had major access site complications. Six patients (0.6%) had subacute vessel closure, but none had this during the first 24 hours after discharge. Same-day discharge radial PCI in certain low-risk patients is a safe and feasible strategy.

Triple antiplatelet therapy during percutaneous coronary intervention is associated with improved outcomes including one-year survival: results from the Do Tirofiban and ReoProGive Similar Efficacy Outcome Trial (TARGET)

OBJECTIVE

We sought to examine if clopidogrel treatment initiated before coronary stenting improved clinical outcomes among patients receiving aspirin and a glycoprotein (GP) IIb/IIIa inhibitor.

BACKGROUND

Antiplatelet therapy plays a pivotal role in contemporary percutaneous coronary interventions (PCI).

METHODS

Outcomes among 4,809 patients randomized to tirofiban or abciximab during PCI with stent placement were compared according to whether they received 300 mg of clopidogrel before PCI (93.1%) versus immediately after the procedure.

RESULTS

The 30-day primary composite end point (death, myocardial infarction [MI], or urgent target vessel revascularization [TVR]) was lower among clopidogrel-pretreated patients (6.6% vs. 10.4%, p = 0.009), mainly because of reduction of MI (6.0% vs. 9.5%, p = 0.012). The benefit of clopidogrel pretreatment was sustained at six months (death, MI, any TVR: 14.6% vs. 19.8%, HR = 0.71, p = 0.010), and this was due mainly to lowering of death and MI (7.8% vs. 13.0%, p = 0.001). At one year, clopidogrel pretreatment was associated with a lower mortality rate (1.7% vs. 3.6%, p = 0.011). Because clopidogrel pretreatment was not randomized, multivariable and propensity analyses were performed. After adjusting for baseline heterogeneity, clopidogrel pretreatment was an independent predictor for death or MI at 30 days (HR = 0.63, p = 0.012) and at six months (HR = 0.61, p = 0.003), and survival at one year (HR = 0.53, p = 0.044). No excess in 30-day bleeding events was noted with clopidogrel pretreatment.

CONCLUSIONS

Among patients undergoing coronary stent placement with aspirin and a GP IIb/IIIa inhibitor, clopidogrel pretreatment is associated with a reduction of death and MI irrespective of the type of GP IIb/IIIa inhibitor used.

Abciximab: an updated review of its therapeutic use in patients with ischaemic heart disease undergoing percutaneous coronary revascularisation

Abciximab (Reopro) is an antibody fragment that dose-dependently inhibits platelet aggregation and leucocyte adhesion by binding to the glycoprotein (GP) IIb/IIIa, vitronectin and Mac-1 receptors. Abciximab (0.25 mg/kg bolus plus infusion of 0.125 micro g/kg/min for 12 hours) showed greater efficacy than tirofiban in reducing the 30-day composite endpoint of death, nonfatal myocardial infarction (MI) or urgent target-vessel revascularisation in the randomised, double-blind TARGET study in patients scheduled for stent placement. In addition, the beneficial effects of treatment with abciximab previously observed in the randomised, multicentre, placebo-controlled EPILOG and EPISTENT studies have been maintained to 1 year, with a significantly reduced incidence of ischaemic complications relative to placebo consistently observed across a range of subgroups including age, sex, bodyweight and indication for revascularisation. The incidence of the composite endpoint was reduced in patients presenting with acute MI of <48 hours' duration in comparison with either fibrinolytic therapy or stenting alone in the randomised STOPAMI and ADMIRAL trials, primarily because of a reduced requirement for urgent repeat revascularisation and reduced incidence of mortality. In the randomised, nonblind, multicentre CADILLAC trial in patients with acute myocardial infarction (MI), stenting alone was superior to percutaneous transluminal coronary angioplasty (PTCA) and stenting alone was not inferior to PTCA plus abciximab. Recent large randomised, multicentre studies (ASSENT-3 and GUSTO-V) have shown higher efficacy (on various ischaemic endpoints) of abciximab in combination with either a reduced dose of tenecteplase or reteplase compared with the fibrinolytic drug alone. TIMI grade 3 flow rates at 60 and 90 minutes in the TIMI-14 and SPEED trials were higher in patients who received abciximab in combination with either alteplase or reteplase than abciximab alone and were similar to that seen with the full-dose fibrinolytic alone. In the randomised, multicentre GUSTO IV-ACS study, no significant differences in any of the ischaemic endpoints at either 7 or 30 days in patients with acute coronary syndromes who were not scheduled to undergo early revascularisation (within 12 hours of end of infusion) were apparent between those who received abciximab (bolus and either 24- or 48-hour infusion) and those who received placebo in addition to aspirin and heparin. The most common adverse events associated with the use of abciximab are bleeding complications and thrombocytopenia, although the risk of major bleeding can be limited through adhering to current administration protocols. Treatment costs are generally higher in both stent plus abciximab and angioplasty plus abciximab groups than stent plus placebo, primarily because of the acquisition cost of abciximab. Abciximab appeared most cost beneficial in high-risk patients undergoing elective percutaneous coronary revascularisation; among lower risk patients, abciximab therapy has been associated with higher total in-hospital and 6-month medical costs than eptifibatide.

CONCLUSION

The GP IIb/IIIa receptor antagonist abciximab, when used with aspirin and heparin, has demonstrated efficacy in reducing the short- and long-term risk of ischaemic complications in patients with ischaemic heart disease undergoing percutaneous coronary intervention, when used with aspirin and heparin. High-risk patients (including those with diabetes mellitus) derive particular benefits from abciximab treatment. Abciximab remains an important therapeutic option for the prevention of complications in patients with ischaemic heart disease.

Angiographic variables predict increased riskfor adverse ischemic events after coronarystenting with glycoprotein IIb/IIIa inhibition

OBJECTIVES

We sought to assess whether pre-procedural angiographic characteristics are associated with adverse clinical outcomes after coronary stenting with glycoprotein IIb/IIIa inhibition.

BACKGROUND

Ischemic complications after balloon angioplasty are associated with pre- and post-procedural angiographic variables. However, in the current era of stenting with IIb/IIIa inhibition, it is unknown whether angiographic features assessed before intervention confer an increased risk of adverse procedural and subsequent clinical outcomes.

METHODS

In the Do Tirofiban and ReoPro Give Similar Efficacy Outcomes? Trial (TARGET), 4,809 patients undergoing planned stenting were randomized to tirofiban or abciximab. Baseline demographic, clinical, and angiographic variables were obtained. Clinical end points were recorded at 30 days and six months. The relationship between angiographic variables and adverse clinical outcomes was assessed.

RESULTS

Patients with the combination of thrombus, lesion eccentricity, and lesion length >20 mm had a 21.4% composite incidence of death, myocardial infarction, or urgent target vessel revascularization (TVR) at 30 days, compared with 4.2% in those patients without these high-risk features (hazard ratio [HR] 3.24, p < 0.001). After adjustment, the risk was independently associated with thrombus (HR 1.40, p = 0.034), eccentricity (HR 1.67, p < 0.001), and lesion length >20 mm (HR 1.89, p < 0.001). The risk of six-month TVR was independently associated with left anterior descending coronary artery lesions (HR 1.46, p < 0.001), restenotic lesions at baseline (HR 1.58, p = 0.006), and lesion length (HR 1.19, p = 0.03).

CONCLUSIONS

Patients with thrombus, eccentric lesions, or lesion length >20 mm are at high risk for ischemic outcomes after coronary stenting, despite IIb/IIIa inhibition. Further research into novel anti-thrombotic therapies or procedural strategies is necessary for these patients.

Decrease of vascular smooth muscle cell locomotion by abciximab, but not tirofiban: a possible role of different affinity to alpha v beta 3 integrins

AIM

The EPISTENT and EPIC studies demonstrated a reduction of clinically driven re-interventions after percutaneous transluminal coronary angioplasty (PTCA) and stent implantation in patients treated with abciximab, while for tirofiban no similar effects could be demonstrated. This may be explained by the different effects on the migratory and invasive potential of vascular smooth muscle cells (VSMCs) by integrin alpha v beta 3 blockade. Therefore, the objective of this study was to compare the effectiveness of abciximab and tirofiban to affect VSMC migration and invasion.

METHODS

Vascular smooth muscle cells were treated with abciximab (0.1-1 microg/ml), tirofiban (0.1-1 microg/ml), and the alpha v beta 3 specific antibody LM609 (1-5 microg/ml), that was used as a positive control during the assay (treatment) over 24 h before the assay (pre-treatment), or before and during the assay (combined treatment). Sodium 3'-[1-(phenylaminocarbonyl)-3,4-tetrazolium]-bis (4-methoxyy-6-nitro) benzene sulfonic acid (XTT)-assay and cell counting measured the influence of the substances on VSMC proliferation. Using a Boyden Chamber model, the capability of VSMCs for migration and invasion was tested with different chemo-attractants and barriers.

RESULTS

Any influence of the platelet glycoprotein (GP) IIb/IIIa receptor (integrin alpha IIb beta 3) antagonists on VSMC proliferation could be excluded. After combined treatment, abciximab demonstrated a dose-dependent inhibition of migration (IC50 = 33 microg/ml) and invasion (IC50 = 0.5 microg/ml) of VSMCs. Administration during the assay without pre-treatment inhibited migration similarly (IC50 = 32 microg/ml) but invasion to a significant lower extent (IC50 = 44 microg/ml). Administration of tirofiban during the assay with or without pre-treatment had no inhibitory effect on VSMC migration and invasion. Pre-treatment alone with one of the substances also did not alter VSMC migration or invasion.

CONCLUSION

Abciximab administration in physiological concentrations was capable of significantly inhibiting the migratory and invasive potential of VSMCs, while for tirofiban no similar effect could be demonstrated.