Effects of glycoprotein IIb/IIIa inhibitors in patients undergoing percutaneous coronary intervention after pretreatment with clopidogrel: a meta-analysis of randomized trials

Integrin αIIbβ3: from discovery to efficacious therapeutic target

From the initial description of platelets in 1882, their propensity to aggregate and to contribute to thrombosis was apparent. Indeed, excessive platelet aggregation is associated with myocardial infarction and other thrombotic diseases whereas Glanzmann thrombasthenia, in which platelet aggregation is reduced, is a bleeding syndrome. Over the last half of the 20th century, many investigators have provided insights into the cellular and molecular basis for platelet aggregation. The major membrane protein on platelets, integrin αIIbβ3, mediates this response by rapidly transiting from its resting to an activated state in which it serves as a receptor for ligands that can bridge platelets together. Monoclonal antibodies, natural products, and small peptides were all shown to inhibit αIIbβ3 dependent platelet aggregation, and these inhibitors became the forerunners of antagonists that proceeded through preclinical testing and into large patient trials to treat acute coronary syndromes, particularly in the context of percutaneous coronary interventions. Three such αIIbβ3 antagonists, abciximab, eptifibatide, and tirofiban, received Food and Drug Administration approval. Over the past 15 years, millions of patients have been treated with these αIIbβ3 antagonists and many lives have been saved by their administration. With the side effect of increased bleeding and the development of new antithrombotic drugs, the use of αIIbβ3 antagonists is waning. Nevertheless, they are still widely used for the prevention of periprocedural thrombosis during percutaneous coronary interventions. This review focuses on the biology of αIIbβ3, the development of its antagonists, and some of the triumphs and shortcomings of αIIbβ3 antagonism.

Efficacy and safety of abciximab in diabetic patients who underwent percutaneous coronary intervention with thienopyridines loading: a meta-analysis

BACKGROUND

It has been controversial whether abciximab offered additional benefits for diabetic patients who underwent percutaneous coronary intervention (PCI) with thienopyridines loading.

METHODS

MEDLINE, EMBASE, the Cochrane library clinical trials registry, ISI Science Citation Index, ISI Web of Knowledge and China National Knowledge Infrastructure (CNKI) were searched, supplemented with manual-screening for relevant publications. Quantitative meta-analyses were performed to assess differences between abciximab groups and controls with respect to post-PCI risk of major cardiac events (MACEs), angiographic restenosis and bleeding complications.

RESULTS

9 trials were identified, involving 2,607 diabetic patients receiving PCI for coronary artery diseases. Among those patients who underwent elective PCI or primary PCI, pooling results showed that abciximab did not significantly reduce risks of MACEs (for elective-PCI patients: RR(1-month): 0.93, 95% CI: 0.60-1.44; RR(1-year): 0.95, 95% CI: 0.81-1.11; for primary-PCI patients: RR(1-month): 1.05, 95% CI: 0.70-1.57; RR(1-year): 0.98, 95% CI: 0.80-1.21), nor all-cause mortality, re-infarction and angiographic restenosis in either group. The only beneficial effect by abciximab appeared to be a decrease 1-year TLR (target lesion revascularization) risk in elective-PCI patients (RR1-year: 0.83, 95% CI: 0.70-0.99). Moreover, occurrence of minor bleeding complications increased in elective-PCI patients treated with abciximab (RR: 2.94, 95% CI: 1.68-5.13, P<0.001), whereas major bleedings rate was similar (RR: 0.83, 95% CI: 0.27-2.57).

CONCLUSIONS

Concomitant dosing of abciximab and thienopyridines provides no additional benefit among diabetic patients who underwent PCI; this conclusion, though, needs further confirmation in larger studies.

[Evaluation of a selective strategy for glycoprotein IIb/IIIa inhibitors administration in non-ST segment elevation acute coronary syndromes]

AIMS

We evaluated the impact of a selective strategy for glycoprotein IIb/IIIa inhibitors administration in non ST-segment elevation acute coronary syndrome.

PATIENTS AND METHOD

Between February 1st, 2007, and February 1st, 2009, 331 consecutive patients were prospectively included in the study. Criteria for upstream glycoprotein IIb/IIIa inhibitors administration were as follows: transient ST elevation greater than 1mm, ST-segment depression greater than 2mm, ischemic recurrence, TIMI risk score greater than 5. Global mortality and cardiovascular outcomes were assessed at Day 7 and Day 30.

RESULTS

The overall use of glycoprotein IIb/IIIa inhibitors was 16%. The procedure was successfully applied in 98%. Compared with non eligible patients (group 1, n = 254), eligible patients (group 2, n = 77) had a higher risk profile, median age: 73 versus 66, p < 0.01, TIMI risk score: 4 versus 3, p < 0.001. Eligible patients (66%) actually received the treatment. Among the 26 eligible but untreated patients, 19% had major bleeding risk, 34% had an unfavourable risk-benefit ratio and 34% were not suitable for an invasive strategy. Cardiovascular events occurred in 5.1% at Day 7 (Group 1, 1.6%), and 6.0% at Day 30 (group 1, 2.4%). Overall mortality at Day 30 was 1.2% (0.4% in Group 1).

CONCLUSION

A strategy for glycoprotein IIb/IIIa inhibitors administration in non ST-segment elevation acute coronary syndrome restricted to 4 very high risk situations may be considered, without evidence for a loss of chance in intermediate risk patients, untreated although eligible for treatment according to the current guidelines.