The impact of GP IIb/IIIa inhibitors during primary percutaneous coronary intervention in acute myocardial infarction patients

The use of glycoprotein (GP) IIb/IIIa inhibitors during percutaneous coronary interventions (PCI) in the acute phase of myocardial infarction (AMI) is still a matter of debate. The aim of the present study was to compare the outcomes of patients with acute ST-segment elevation myocardial infarction who underwent primary PCI and were concomitantly treated with GP IIb/IIIa inhibitors with those who were not treated with these drugs. Between January 1996 and November 2003, a total of 418 consecutive patients underwent PCI in the setting of ST-segment elevation AMI. At the operator's discretion, 287 patients were concomitantly treated with GP IIb/IIIa inhibitors and 115 patients were not. Angiographic success and final TIMI 3 flow in the infarct-related artery was achieved more frequently in patients treated with GP IIb/IIIa inhibitors (90% vs. 77%; p=0.001). The in-hospital composite endpoint of death, reinfarction and bleeding complications was significantly better in patients treated with GP IIb/IIIa inhibitors (4% vs. 12%; p=0.005). Furthermore, the adjusted 12-month survival rate was significantly better in these patients (RR: 2.99, CI: 1.29-6.9; p=0.01). Therefore, adjunctive therapy with GP IIbIIIa inhibitors during primary PCI is associated with improved short-term outcomes and one-year survival without an increased risk of bleeding.     

Patterns of upstream antiplatelet therapy use before primary percutaneous coronary intervention for acute ST-elevation myocardial infarction (from the CRUSADE National Quality Improvement Initiative)

We sought to determine the usage patterns and impact of upstream glycoprotein IIb/IIIa inhibitor and clopidogrel in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI). We studied trends in the use of upstream glycoprotein IIb/IIIa inhibitors and clopidogrel in 3,895 patients with STEMI undergoing primary PCI at 124 hospitals in the United States participating in the CRUSADE initiative from March 2005 to December 2006. Administration of these agents >15 minutes before PCI was considered pre-PCI use, and administration < or =15 minutes before, during, and after PCI was considered peri-PCI use. A total of 3,566 patients (91.6%) received glycoprotein IIb/IIIa inhibitors within 24 hours of presentation, of whom 1,225 (34.4%) received this medication before PCI. Similarly, 3,785 patients (97.2%) received clopidogrel within 24 hours of presentation, of whom 1,029 (27.2%) received this medication before PCI. From 2005 to 2006, pre-PCI glycoprotein IIb/IIIa inhibitor use decreased from 43.4% to 33.5%, whereas pre-PCI clopidogrel use increased from 21.2% to 31.5%. Clinical characteristics, risk of adverse outcomes, and bleeding events were similar in the pre- versus peri-PCI glycoprotein IIb/IIIa inhibitor and clopidogrel cohorts, respectively. In conclusion, most patients with STEMI undergoing primary PCI receive glycoprotein IIb/IIIa inhibitors and clopidogrel, but only (1/3) are treated upstream with these agents and this upstream use does not have a significant impact on outcomes. These results indicate that further studies are needed to determine the optimal dosing and timing of antiplatelet therapies for patients undergoing primary PCI.     

Rationale and design of the ETN-STEP (Early administration of Tirofiban in mid to high risk patients with non-ST elevation acute coronary syndrome referred for percutaneous coronary intervention) project: A multi-center, randomized, controlled clinic trial in Chinese patients

As a member of Glycoprotein IIb/IIIa (GP IIb/IIIa) inhibitors, Tirofiban had been shown to improve myocardial reperfusion and clinical outcomes in patients undergoing percutaneous coronary intervention (PCI), but the optimal timing of administration of Tirofiban remains unclear. In order to compare the effects of upstream versus downstream administration of Tirofiban in Chinese patients with mid to high risk, non-ST elevation acute coronary syndrome (ACS) referred for PCI, a multicenter, randomized, controlled, prospective study will be conducted. A total of 500 mid to high risk, non-ST-segment elevation myocardial infarction (NSTEMI) ACS patients will be recruited for this study. Patients will be randomized to Tirofiban upstream administration group (initiated 12 h before PCI) and Tirofiban downstream administration group (initiated at cath-lab after angiography). Thrombolysis in myocardial infarction (TIMI) flow grades, TIMI myocardial perfusion grades (TMPG), and Corrected TIMI frame counting (CTFC) before and after PCI, as well as clinical outcomes during the hospital stay, and within 30 days after PCI will be compared between the two groups. This study will provide evidence on the optimal timing for initiating administration of Tirofiban in mid to high NSTEMI ACS subjects undergoing PCI.     

Effectiveness and safety of glycoprotein IIb/IIIa inhibitors and clopidogrel alone and in combination in non-ST-segment elevation myocardial infarction (from the National Registry of Myocardial Infarction-4)

We investigated whether a combination of clopidogrel and glycoprotein (GP) IIb/IIIa inhibitors safely decreases hospital mortality, reinfarction, and major bleeding beyond either therapy alone in patients with non-ST-elevation myocardial infarction (NSTEMI). GP IIb/IIIa inhibitors and clopidogrel, separately, have been shown to decrease adverse outcomes in patients with non-ST-elevation acute coronary syndromes, but the need for combination therapy is uncertain. Multivariate and propensity analyses compared the frequency of death, reinfarction, and major bleeding during hospitalization in 38,691 patients with NSTEMI who were enrolled in the National Registry of Myocardial Infarction 4 from July 2000 to December 2003. Of these, 65% received GP IIb/IIIa inhibitors only, 16.1% clopidogrel only, and 18.8% combination therapy. Among patients who did not undergo percutaneous coronary intervention (PCI), the composite end point of death, reinfarction, and major bleeding was significantly lower with combination therapy than with GP IIb/IIIa inhibitors alone (odds ratio 0.77, 95% confidence interval 0.67 to 0.88). In contrast, this composite end point was significantly higher when combination therapy was employed rather than clopidogrel alone (odds ratio 1.55, 95% confidence interval 1.33 to 1.81). However, among patients who underwent PCI, the composite end point was similar between combination therapy and GP IIb/IIIa inhibitor-only groups (odds ratio 1.01, 95% confidence interval 0.89 to 1.14). Further, there was a strong trend toward a higher composite end point among patients who received combination therapy rather than clopidogrel alone (odds ratio 1.31, 95% confidence interval 0.99 to 1.72). In conclusion, commonly employed strategies using a GP IIb/IIIa inhibitor alone or with the combination of clopidogrel plus GP IIb/IIIa inhibitor in NSTEMI may not be justified in comparison with a simpler strategy of clopidogrel used alone, especially in patients who have not undergone PCI.     

Glycoprotein IIb/IIIa inhibition in the setting of acute ST-segment elevation myocardial infarction

Glycoprotein (GP) IIb/IIIa inhibitors have been extensively studied in the setting of percutaneous coronary intervention (PCI) and in the management of non-ST-segment elevation acute coronary syndromes. However, the use of GP IIb/IIIa inhibitors is less well established in the setting of acute ST-segment elevation myocardial infarction (MI). Multiple nonrandomized studies suggest that combination therapy with GP IIb/IIIa inhibitors and thrombolytic agents leads to increased rates of TIMI 3 flow. However, two clinical trials involving over 22,000 patients demonstrated that combination therapy is associated with only modest reductions in major adverse cardiac events, does not reduce mortality, and is associated with an increase in bleeding. In the setting of primary PCI, four clinical trials involving over 3,000 patients demonstrated that GP IIb/IIIa inhibition results in a significant decrease in the need for urgent target vessel revascularization but not in reductions of death or recurrent MI. Thus, GP IIb/IIIa inhibition may provide only limited benefits in the setting of acute ST-segment elevation MI.     

Small peptide GP IIb/IIIa receptor inhibitors as upstream therapy in non-ST-segment elevation acute coronary syndromes: results of the PURSUIT, PRISM, PRISM-PLUS, TACTICS, and PARAGON trials.

The primary pathophysiologic mechanism underlying all non-ST-segment elevation acute coronary syndromes (NSTE ACS) is the formation of platelet-rich coronary thrombi in response to spontaneous or intervention-induced endothelial damage with exposure of subendothelial substrates. Antagonists of the glycoprotein (GP) IIb/IIIa receptor ameliorate this process by blocking the final common pathway for platelet aggregation. Based upon collective data in over 24,000 patients, clinical trials have demonstrated that treatment of NSTE ACS patients with GP IIb/IIIa agents results in an approximate 12% relative risk reduction in the incidence of death or myocardial infarction at 30 days. The magnitude of this clinical benefit is increased in patients who are troponin-positive and who are referred for early percutaneous intervention. Potential benefits of GP IIb/IIIa inhibitor use must be weighed against an increased risk of bleeding. Ongoing controversies exist concerning the relative efficacy of different GP IIb/IIIa antagonists, the accurate use of platelet function tests to define safe and efficacious drug dosing, the adjunctive use of additional anti-thrombotic agents, and the optimal timing of upstream therapy before diagnostic cardiac catheterization and revascularization.     

Planned versus provisional use of glycoprotein IIb/IIIa inhibitors in smokers undergoing percutaneous coronary intervention

Postmortem and angiographic studies have demonstrated that thrombosis is the primary cause of coronary artery occlusion in smokers. Further, smokers have high levels of fibrinogen, increased platelet aggregation, and more platelet-dependent thrombin generation than do nonsmokers, suggesting that glycoprotein (GP) IIb/IIIa inhibitor use during percutaneous coronary intervention (PCI) may be especially useful among smokers. We evaluated a subpopulation of active smokers in the REPLACE-2 trial to assess the effect of treating smokers with bivalirudin and provisional GP IIb/IIIa blockade compared with heparin and planned GP IIb/IIIa blockade. The REPLACE-2 trial enrolled 1,558 smokers and 4,305 nonsmokers. Smokers who were treated with bivalirudin had an absolute 3.2% increase in the composite end point of death and myocardial infarction at 48 hours compared with smokers who were treated with heparin and GP IIb/IIIa inhibitors (7.7% vs 4.5%, p=0.008, interaction p=0.016). This difference was ameliorated when GP IIb/IIIa inhibitors were used consistently in a previous trial that compared bivalirudin with heparin during PCI (4.6% vs 6.7%, p=0.322). In conclusion, these results suggest that smokers may derive particular benefit with GP IIb/IIIa inhibitors for decreasing myocardial infarction and death after PCI. These findings require further validation from other large, randomized trials.     

Use of platelet glycoprotein IIb/IIIa inhibitors in saphenous vein graft percutaneous coronary intervention and clinical outcomes

Platelet glycoprotein (GP) IIb/IIIa inhibitors are widely used in percutaneous coronary intervention (PCI). Previous studies have suggested that they do not offer benefit in saphenous vein graft PCI. Nonetheless, their use remains widespread during vein graft angioplasty. We retrospectively analyzed 1,537 patients who underwent saphenous vein graft PCI. Patients who received a GP IIb/IIIa inhibitor (n = 941) were compared with those who did not receive any GP IIb/IIIa inhibitor (n = 596). The primary end point was myonecrosis after PCI (creatine kinase-MB level >3 times the upper reference limit). The incidence of myonecrosis after PCI was similar between the group that received GP IIb/IIIa and the group that did not (odds ratio for GP IIb/IIIa use 1.39, 95% confidence interval 0.97 to 2.00, p = 0.07). Propensity-adjusted analysis demonstrated no significant difference in myonecrosis after PCI, in-hospital mortality, Q-wave myocardial infarction, or bleeding (blood transfusion, retroperitoneal bleed, or hematoma) between the 2 groups. In an analysis restricted to patients who were treated with an emboli protection device, GP IIb/IIIa use was not associated with decreased myonecrosis after PCI (this was also the case for patients who were not treated with an emboli protection device). Unadjusted survival (mean follow-up 5.5 +/- 0.1 years) was similar between the group that received GP IIb/IIIa and the group that did not (log-rank test, p = 0.89). There was no difference in survival after adjusting for the propensity to receive a GP IIb/IIIa inhibitor (adjusted odds ratio for GP IIb/IIIa use 0.92, 95% confidence interval 0.69 to 1.23, p = 0.59). In conclusion, adjunctive use of platelet GP IIb/IIIa inhibitors in saphenous vein graft PCI does not appear to be associated with less myonecrosis or improved survival.     

A propensity analysis of the impact of platelet glycoprotein IIb/IIIa inhibitor therapy on in-hospital outcomes after percutaneous coronary intervention

It is unknown whether the benefits of parenteral platelet glycoprotein (GP) IIb/IIIa inhibitors as an adjunct to percutaneous coronary intervention (PCI) demonstrated in randomized clinical trials extend to patients treated outside the setting of clinical trials. A contemporary registry of 10,847 consecutive PCI procedures was analyzed to determine the effect of GP IIb/IIIa inhibitor treatment on in-hospital major adverse coronary events ([MACEs] composite of death, urgent coronary artery bypass surgery, periprocedural myocardial infarction, abrupt closure, and stent thrombosis). In this registry, GP IIb/IIIa inhibitors were administered to 20.1% of patients. These patients were younger, more often men, and less often hypertensive than untreated patients. GP IIb/IIIa inhibitor-treated patients were more likely to present with acute myocardial infarction or unstable angina. Stents were placed in 79% of patients treated with GP IIb/IIIa inhibitors. MACEs occurred in 7.8% of GP IIb/IIIa inhibitor-treated patients compared with 3.8% of untreated patients (p <0.001). After multivariable adjustment for the propensity of GP IIb/IIIa inhibitor treatment as well as other possible confounders and interactions known to influence MACEs, GP IIb/IIIa inhibitor treatment was associated with a 57% increase in the risk of a MACE (odds ratio 1.57, 95% confidence interval 1.22 to 2.03; p = 0.0004). In a data set consisting of patients with a high degree of acuity predominantly treated with stent placement, GP IIb/IIIa inhibitor treatment is associated with an increase in thrombotic complications of PCI.     

The role of risk stratification in the decision to provide upstream versus selective glycoprotein IIb/IIIa inhibitors for acute coronary syndromes: a cost-effectiveness analysis.

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.     

Glycoprotein IIb/IIIa inhibitors during rescue percutaneous coronary intervention in acute myocardial infarction

Although percutaneous coronary intervention (PCI) following full-dose thrombolytic therapy (rescue angioplasty) is a common procedure, there is ample controversy regarding the usefulness of the procedure. Moreover, few data are available concerning the safety and efficacy of concomitant treatment with glycoprotein (GP) IIb/IIIa inhibitors in these patients. The aim of the present study was to compare the clinical outcomes of patients who underwent rescue PCI with stents and were treated with GP IIb/IIIa inhibitors. A total of 59 consecutive patients underwent rescue PCI at our institution during the study period, 29 patients (49.2%) were treated concomitantly with a GP IIb/IIIa inhibitor and 30 patients (50.8%) were not. Baseline clinical characteristics were similar between the two groups. In-hospital outcomes regarding death, reinfarction and the need for urgent target vessel revascularization was significantly lower in patients treated with GP IIb/IIIa inhibitors compared to those who were not treated (3.4% vs. 26.7%; p = 0.01, respectively). However, GP IIb/IIIa inhibitor administration was not an independent predictor of better outcomes by multivariate analysis. There was a higher rate of major bleeding complications in patients who received GP IIb/IIIa inhibitors, though it did not achieve statistical significance (6.9% vs. 0%; p = 0.14, respectively). The composite endpoint of major, minor bleeding and vascular complications was similar in both groups (24.1% vs. 16.7%; p = 0.48). In conclusion, the administration of GP IIb/IIIa inhibitors in patients undergoing rescue PCI after failed thrombolysis with stents was safe and may have a beneficial effect on 30-day event-free survival rates, without a significant increase in bleeding or vascular complications. These results warrant further investigation.     

Interpretation of new treatment guidelines for non-ST-segment elevation acute coronary syndromes: "ischemia-guided" versus "early invasive" strategies

The American College of Cardiology/American Heart Association Task Force on Practice Guidelines has recently published recommendations regarding the diagnosis and management of patients with non-ST-segment elevation (NSTE) acute coronary syndromes (ACS). Conventional therapy for non-ST-segment elevation acute coronary syndrome (NSTE ACS) has traditionally employed an "ischemia-guided" approach in which diagnostic cardiac catheterization and revascularization are only used in patients with objective-evidence of residual myocardial ischemia as identified by recurrent symptoms or provocative stress testing. More recent studies, however, have demonstrated improved clinical outcomes with the use of an "early invasive" approach, employing routine coronary angiography early in the patient's hospital course, followed by percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG) surgery where appropriate. Improved clinical outcomes associated with an "early invasive" strategy may have evolved as a consequence of recent advances in both adjunctive pharmacotherapy and revascularization technique. For example, use of GP IIb/IIIa inhibitors and/or low-molecular-weight heparin prior to catheterization have been shown to reduce clinical events in NSTE ACS patients, and may reduce the risk of an invasive approach by plaque passivation prior to interventional therapy. Perhaps more importantly, the combined use of GP IIb/IIIa inhibitors and intracoronary stenting may reduce the potential early hazard of an invasive approach by specifically decreasing the incidence of death and non-fatal myocardial infarction associated with percutaneous intervention. In spite of the benefits of this synergistic combination of pharmacology and mechanical revascularization, risk stratification remains important in identifying high-risk individuals most likely to benefit from an "early invasive" approach.     

Association of glycoprotein IIb/IIIa inhibitors and long-term survival following administration during percutaneous coronary intervention for acute myocardial infarction

Objectives: We sought to evaluate the impact of GP IIb/IIIa receptor blockers on long-term mortality in patients undergoing PCI for AMI. Background: Glycoprotein (GP) IIb/IIIa inhibitors are potent suppressors of platelet aggregation and when used during percutaneous coronary intervention (PCI) for the treatment of acute myocardial infarction (AMI) may improve short-term clinical outcomes, including survival. However, the impact of GP IIb/IIIa treatment during PCI for AMI on long-term survival is unknown. Methods: Patients undergoing primary or rescue PCI for AMI within 24 hours of symptom onset with or without GP IIb/IIIa inhibitor treatment were identified from a multicenter PCI database. All cause mortality at a mean follow-up of 3 years was the primary end point. Results: Of the 269 patients treated with primary or rescue PCI for AMI, 107 (40%) received a GP IIb/IIIa antagonist. Patients treated with GP inhibitors were more likely to present with or develop heart failure (13% vs. 6.2%, P = 0.052). Left ventricular ejection fraction was reduced in those treated with GP IIb/IIIa antagonists (44% vs. 48%, P = 0.051). The extent of coronary artery disease did not differ between groups. Stent use was 80% in both groups. Procedural success was high and did not differ between groups. In-hospital mortality was low and did not differ between groups. The mortality at a mean follow-up of 3 years was 1.9% among patients treated with a GP IIb/IIIa antagonist and 15% for those who were not treated (log-rank P = 0.0005). Treatment with a GP IIb/IIIa antagonist was independently associated with a significant reduction in the hazard of long-term mortality (Hazard Ratio, 0.159; 95% Confidence Interval, 0.034–0.729; P = 0.018). Conclusions: Treatment of patients undergoing PCI for AMI with GP IIb/IIIa antagonists appears to be associated with a profound reduction in late mortality.     

Low-molecular-weight heparin compared with unfractionated heparin for patients with non–ST-segment elevation acute coronary syndromes treated with glycoprotein IIb/IIIa inhibitors: Results from the CRUSADE initiative

Background: Both heparin and glycoprotein (GP) IIb/IIIa inhibitor therapy and early invasive management strategies are recommended by the American College of Cardiology (ACC)/American Heart Association (AHA) guidelines for the treatment of patients with non–ST-segment elevation acute coronary syndromes (NSTE ACS). However, controversy exists about which form of heparin—unfractionated (UF) or low-molecular-weight (LMW)—is preferable. We sought to compare the efficacy and safety of these treatment strategies in a large contemporary population of patients with NSTE ACS. Methods: Using data from the CRUSADE Initiative, we evaluated LMWH and UFH in high-risk NSTE ACS patients (positive cardiac markers and/or ischemic ST-segment changes) who had received early (< 24 hours) GP IIb/IIIa inhibitor therapy and underwent early invasive management. In-hospital outcomes were compared among treatment groups. Results: From a total of 11,358 patients treated at 407 hospitals in the US from January 2002–June 2003, 6881 (60.6%) received UFH and 4477 (39.4%) received LMWH. Patients treated with UFH were more often admitted to a cardiology inpatient service (73.6% vs. 65.5%, P < 0.0001) and more frequently underwent diagnostic catheterization (91.8% vs. 85.9%, P < 0.0001) and percutaneous coronary intervention (PCI) (69.7% vs. 56.9%, P < 0.0001) than patients treated with LMWH. The point estimate of the adjusted risk of in-hospital death or reinfarction was slightly lower among patients treated with LMWH (odds ratio [OR] 0.81, 95% confidence interval [CI] 0.67–0.99) and the risk of red blood cell transfusion was similar (OR 1.01, 95% CI 0.89–1.15). Among patients who underwent PCI within 48 hours, adjusted rates of death (OR 1.14, 95% CI 0.71–1.85), death or reinfarction (OR 0.93, 0.67–1.31), and transfusion (OR 1.16, 0.89–1.50) were similar. Patients who underwent PCI more than 48 hours into hospitalization had reduced rates of death (OR 0.64, 0.46–0.88), death or reinfarction (OR 0.57, 0.44–0.73), and transfusion (OR 0.66, 0.52–0.84). Conclusions: In routine clinical practice, patients treated with GP IIb/IIIa inhibitors have slightly improved outcomes and similar bleeding risks with LMWH than with UFH. These findings are consistent with current ACC/AHA guidelines but raise important questions about the safety and effectiveness of antithrombotic therapy in real-world clinical practice. Abbreviations abstract Using data from the CRUSADE Initiative, we evaluated low-molecular-weight heparin (LMWH) and unfractionated heparin (UFH) in high-risk patients with non–ST-segment elevation acute coronary syndromes (NSTE ACS) who received early (<24 hours) glycoprotein (GP) IIb/IIIa inhibitors and early invasive management. In-hospital outcomes were compared among treatment groups. LMWH was associated with slightly improved clinical outcomes and similar rates of transfusion compared with UFH. Our results support the current ACC/AHA guidelines recommendations but raise concerns about the safety and efficacy of UFH in the setting of background use of upstream GP IIb/IIIa inhibitors for patients with NSTE ACS in routine clinical practice. CRUSADE is funded by Millennium Pharmaceuticals, Inc. (Cambridge, Massachusetts) and Schering Corporation (Kenilworth, New Jersey). Bristol-Myers Squibb/Sanofi Pharmaceuticals Partnership provides an unrestricted grant in support of the program.     

The combination of enoxaparin, glycoprotein IIb/IIIa inhibitors and an early invasive approach among acute coronary syndrome patients

OBJECTIVES: This study was designed to assess the feasibility and safety of enoxaparin in combination with glycoprotein (GP) IIb/IIIa inhibitors during percutaneous coronary intervention (PCI) as part of an early invasive strategy in patients presenting with acute coronary syndromes (ACS). BACKGROUND: Trials in patients with ACS have evaluated the utility of enoxaparin, adjuvant GP IIb/IIIa inhibitors with PCI, and an early invasive approach. Information about the combination of all three of these approaches, however, is limited. METHODS: Forty-nine patients with ACS underwent cardiac catheterization, of whom 23 underwent PCI with enoxaparin and GP IIb/IIIa inhibitors. RESULTS: The primary endpoint of the study, a composite of death, myocardial infarction or urgent revascularization at 30 days, occurred in 8% of patients undergoing PCI. There were no deaths. One patient received a blood transfusion. No other adverse events occurred. These event rates were comparable to those from the pooled EPILOG/EPISTENT database, in which intravenous unfractionated heparin was used in conjunction with GP IIb/IIIa receptor blockade. The mean anti-Xa level in patients undergoing PCI was 0.74 0.48 U/ml. The majority of patients who underwent PCI within eight hours of their last dose of enoxaparin had therapeutic anti-Xa levels. CONCLUSION: In patients with ACS, enoxaparin in combination with GP IIb/IIIa inhibitors and an early invasive approach resulted in comparable clinical complication and bleeding rates versus historical references utilizing unfractionated heparin.     

Bleeding risk of platelet glycoprotein IIb/IIIa receptor antagonists in broad-based practice (results from the Society for Cardiac Angiography and Interventions Registry)

Randomized trials of platelet glycoprotein (GP) IIb/IIIa receptor inhibitors in patients who have undergone percutaneous coronary intervention (PCI) have shown a modest increase in bleeding risk associated with GP IIb/IIIa inhibitor use. Because clinical trials often enroll highly selected patient populations and are performed in high-volume experienced centers, these results may not apply to a nonclinical trial population, thus altering the risk-benefit ratio of the drugs. Given the widespread use of these agents, we sought to determine bleeding risks in a broad-based population of patients who underwent PCI. We performed a retrospective cohort study of GP IIb/IIIa inhibitors and bleeding in 18,821 procedures from June 1, 1996 to December 31, 1998 using the Society for Cardiac Angiography and Interventions Registry. The primary outcome was bleeding events, defined as clinically significant hematoma formation or hemorrhage. Bleeding risk was 1.9% in the 2,525 patients who received GP IIb/IIIa inhibitors compared with 1.0% in the 16,296 who did not (unadjusted odds ratio [OR] 1.87, 95% confidence interval [CI] 1.35 to 2.59, p <0.001). After adjustment for multiple clinical and procedural variables, the effect was attenuated, with at most a twofold bleeding risk associated with GP IIb/IIIa inhibitor use (adjusted OR 1.39, 95% CI 0.96 to 2.03, p = 0.083). The small increase in absolute risk of bleeding from GP IIb/IIIa inhibitor use in this study is similar to the risk observed in clinical trials. Assuming these agents are as effective as shown in these trials, the risk-benefit ratio of GP IIb/IIIa inhibitors in broad-based PCI practice should be favorable.     

Profound thrombocytopenia associated with tirofiban: case report and review of literature

Platelet glycoprotein (GP)IIb/IIIa inhibitors prevent fibrinogen binding and platelet aggregation. Inhibition of platelet activity at the injured coronary plaque is a target for novel therapeutic strategies. They decrease ischemic complications associated with non-ST-segment elevation acute coronary syndromes and percutaneous coronary intervention. Thrombocytopenia is a serious complication well described with the use of the prototype GP IIb/IIIa inhibitor abciximab. Its association with other agents of this class has been underemphasized. It is important to monitor platelet counts closely after initiation of GP IIb/IIIa inhibitor therapy, not only for abciximab, but also for small molecule inhibitors such as eptifibatide and tirofiban. Monitoring of platelet counts at 2 to 6 hours and 24 hours will detect most cases of acute thrombocytopenia. Adverse events may be prevented by prompt discontinuation of GP IIb/IIIa inhibitor therapy. The authors present a case of profound thrombocytopenia after the administration of tirofiban in the treatment of a patient with an acute coronary syndrome.     

What anti‐thrombotic therapy is best with primary PCI for acute ST elevation myocardial infarction: How should the HORIZONS trial change current practice?

The current standard of care for anti‐thrombotic therapy with primary PCI for acute ST elevation myocardial infarction (STEMI) is aspirin, clopidogrel, unfractionated heparin and platelet glycoprotein IIb/IIIa inhibitors. However, heparin and glycoprotein IIb/IIIa inhibitors are associated with a high incidence of bleeding, and many of the trials documenting benefit with this therapy were performed before the widespread use of stents and clopidogrel. Bivalirudin is a direct thrombin inhibitor which has been found to have similar efficacy with less bleeding compared with heparin plus glycoprotein IIb/IIIa inhibitors when used with elective PCI and with PCI for unstable angina and non‐ST elevation myocardial infarction. The HORIZONS trial evaluated bivalirudin compared with unfractionated heparin and IIb/IIIa inhibitors in patients with STEMI treated with primary PCI and found similar MACE (major adverse cardiac events) with less bleeding and a lower incidence of net adverse clinical events (MACE or major bleeding) at 30 days. Mortality at 30 days was also significantly less with bivalirudin. These results make a strong case for the use of bivalirudin with primary PCI in the great majority of patients with STEMI, with the possible exception of patients with cardiogenic shock or stent thrombosis, and patients with a large thrombus burden or no re‐flow following PCI. In the latter case, platelet glycoprotein IIb/IIIa inhibitors would be used as a bail‐out strategy. © 2008 Wiley‐Liss, Inc.     

Antiplatelet Strategies: Evaluating Their Current Role in the Setting of Acute Coronary Syndromes

Numerous clinical trials have established the value of antiplatelet therapies for acute coronary syndromes (ACS). Aspirin (ASA), thienopyridines (i.e., clopidogrel and ticlopidine) and GP IIb/IIIa antagonists comprise the major classes of antiplatelet therapies demonstrated to be of benefit in the treatment of ACS and for the prevention of thrombotic complications of percutaneous coronary intervention (PCI). Clopidogrel is beneficial when administered before and after PCI, and is more effective when combined with either ASA or GP IIb/IIIa inhibitors in preventing post‐PCI complications, coronary subacute stent thrombosis, and thrombotic events in general. It is currently unclear whether a higher loading dose of clopidogrel (600 mg) is better than the standard loading dose (300 mg), how long therapy should continue, and which maintenance dose is optimal. The role of the GP IIb/IIIa antagonists in ACS is less clear due to conflicting data from several studies with different patient populations. Currently, it appears that the use of GP IIb/IIIa antagonists might be most beneficial in high‐risk ACS patients scheduled to undergo PCI, who demonstrate non‐ST‐segment elevation myocardial infarction and elevated troponin levels. Copyright © 2008 Wiley Periodicals, Inc.     

GP IIb/IIIa inhibitors during primary percutaneous coronary intervention for STEMI: New trial and registry data

Primary percutaneous coronary intervention (PCI) with adjunctive glycoprotein (GP) IIb/IIIa receptor inhibitor therapy administered in the cardiac catheterization laboratory is the optimal reperfusion strategy for patients with ST-elevation myocardial infarction. Most available data regarding these agents are from trials comparing abciximab to placebo alone. Noninferiority trials comparing small-molecule GP IIb/IIIa receptor inhibitors, such as tirofiban and eptifibatide with abciximab, have used markers for myocardial reperfusion as primary end points but are underpowered to detect significant differences in hard clinical outcomes. Such a trial would need to enroll a very large number of patients and thus make it practically impossible to perform. Registry data reveal that most patients undergoing primary PCI are treated with small-molecule GP IIb/IIIa receptor inhibitors in clinical practice, and no observed difference is observed in safety and efficacy when compared with patients treated with abciximab therapy.