Dual antiplatelet therapy in coronary artery disease: A case-based approach
ABSTRACTCurrent guidelines support dual antiplatelet therapy with aspirin and clopidogrel (Plavix) in a number of clinical scenarios, ie, in ST-segment-elevation myocardial infarction (MI), non-ST-elevation MI, and percutaneous coronary intervention. The guidelines are based on strong evidence from several large randomized clinical trials over the last 10 years. The authors present several cases to show how to put this evidence into day-to-day clinical practice.
KEY POINTS
- Dual antiplatelet therapy is recommended after ST-elevation MI or non-ST-elevation acute coronary syndromes, with aspirin indefinitely and clopidogrel for up to 1 year.
- Dual antiplatelet therapy is recommended for at least 1 month after placement of a bare-metal stent and for at least 1 year (or possibly indefinitely) after placement of a drug-eluting stent.
- There is no compelling indication for clopidogrel in patients with chronic coronary artery disease.
- Compared with clopidogrel, prasugrel (Effient) is associated with lower rates of MI, urgent target-vessel revascularization, and in-stent thrombosis, but at the cost of a higher risk of major bleeding.
CASE 2: NON-ST-ELEVATION ACUTE CORONARY SYNDROME
A 65-year-old woman living independently with no significant medical history presents to the emergency room with 2 hours of waxing and waning substernal chest pain. Her blood pressure is 145/90 mm Hg, her heart rate is 95 beats per minute, and the results of her physical examination are unremarkable. Resting electrocardiography reveals 1.5-mm ST-segment depression in the inferior leads, and her troponin T level on admission is two times the upper limit of normal. She is given aspirin and is started on low-molecular-weight heparin and intravenous nitroglycerin.
What would be the value of starting clopidogrel in this patient?
Clopidogrel in non-ST-elevation acute coronary syndromes
The ACC/AHA guidelines strongly support starting clopidogrel in patients with non-ST-elevation acute coronary syndromes (Table 2).5
The CURE trial (Clopidogrel in Unstable Angina to Prevent Recurrent Events)11 provided the evidence for this recommendation. In this trial, 12,562 patients from 482 centers in 28 countries who presented within 24 hours of coronary symptoms, without ST elevation, were randomized to receive either clopidogrel (a 300-mg loading dose, followed by 75 mg daily) or placebo for 3 to 12 months (mean 9 months).
Significantly fewer patients in the clopidogrel group reached one of the end points of the composite primary outcome (cardiovascular death, nonfatal MI, or stroke): 9.3% vs 11.4%, 95% confidence interval (CI) 0.72–0.90, P < .001. Significantly fewer of them also suffered one of the secondary outcomes, ie, severe ischemia, heart failure, or need for revascularization.
Of concern was a higher rate of major bleeding in the clopidogrel group (3.7%) than in the placebo group (2.7%) without an excess of fatal bleeding. For every 1,000 patients treated with clopidogrel, 6 required a blood transfusion. Nevertheless, CURE proved that patients with non-ST-elevation acute coronary syndromes benefited from clopidogrel, regardless of whether they underwent percutaneous coronary intervention.
Comment. Our patient should receive clopidogrel and, if she has no significant bleeding, she should continue to take it for at least 12 months after discharge. It is important for the primary care physician to ensure compliance with this agent and not discontinue it on routine clinical follow-up.
