Clopidogrel and risk for acute coronary events

Clopidogrel Response Variability: Review of the Literature and Practical Considerations

Dual antiplatelet therapy with aspirin and a P2Y12 inhibitor is standard therapy following acute coronary syndrome and percutaneous coronary intervention. Despite the use of potent antiplatelet agents, vascular events continue to occur. Lack of response to clopidogrel therapy has been widely investigated using various methods of platelet function testing. These studies have consistently found an association between poor clopidogrel response and an increased risk of vascular events. Strategies to overcome this problem include higher clopidogrel doses or the use of an alternative P2Y12 agent. To date, the majority of studies investigating tailored antiplatelet therapy have failed to show any reduction in clinical events likely due to the low-risk population studied. Despite this lack of benefit from altering therapy, platelet function testing may be done in certain patient populations. Patients at high risk of deleterious outcomes from stent thrombosis may be an appropriate patient population for platelet function testing to ensure adequate response to therapy. In addition, emerging data suggests a potential role for platelet function testing to assess for bleeding risk. The purpose of this article is to review the key studies demonstrating response variability to clopidogrel therapy, strategies to overcome variability, and practical considerations for the clinician.

Colonoscopy with Polypectomy in Patients Taking Clopidogrel

BACKGROUND AND AIMS

To investigate the bleeding risk of colonoscopy with polypectomy in patients taking clopidogrel.

METHODS

Retrospective review of patients undergoing colonoscopy with polypectomy without interruption of clopidogrel. Patients with lesions larger than 1cm were generally rescheduled for polypectomy off clopidogrel. Most of the polyps were removed using cold snare technique. Endoscopic clips were routinely applied prophylactically.

RESULTS

A total of 125 polypectomies were performed in 60 patients. The average polyp size was 5.4 ± 2.1 mm. One patient (1.7%, CI 0.3-8.9%) developed post-polypectomy bleeding that resolved without treatment. Three patients (5%, CI 1.7-14%) had immediate bleeding during the procedure and all resolved with prompt clip application.

CONCLUSIONS

Polypectomy of lesions up to 1cm in size can be performed without interruption of clopidogrel.

Clopidogrel and coronary stents: risks and benefits

Clopidogrel has become increasingly important in the management of patients with coronary stents. Clopidogrel is an oral agent that acts on the adeno-sine diphosphate receptor to irreversibly inhibit platelet aggregation. Along with aspirin, clopidogrel has a significant role in the treatment of atherothrombotic diseases. Recent concerns about late stent thrombosis highlight the need for long-term therapy with clopidogrel in addition to aspirin in these populations. This article reviews the role of clopidogrel in the treatment of atherothrombotic diseases and after coronary intervention, as well as the current approach in the prevention of stent thrombosis. It also discusses experimental and upcoming drugs that may be superior to clopidogrel.