Thursday, March 16, 2006

Basket Late Study

This study was presented at the just completed ACC annual scientific meeting at Atlanta, Georgia. Dr M. Pfisterer presented his findings in a study of 743 patients who had either a paclitaxel eluting stent, or a sirolimus eluting stent or a bare metal stent, in a 1:1:1 proportion. The aim of the study was to evaluate late thrombotic events among patients treated with drug eluting stents vs bare metal stents 1 year after clopidogrel discontinuation. The study population comprised of 21% ST elevation MI patients, 37% unstable angina, and 42% stable angina. Multivessel disease was present in 67%, and the culprit artery was the left anterior descending in 51% of patients. An average of 1.9 stents was used per patient.

The authors found that in the year following clopidogrel discontinuation, the primary composite endpoint of cardiac death or MI occurred significantly more frequently in the drug-eluting stent group (4.9% vs 1.3%, p=0.01). Non-fatal MI was also higher in the drug-eluting stent group (4.1% vs 1.3%, p=0.04) and cardiac death trended higher (1.2% vs 0%, p=0.09). There was no difference in restenosis driven target vessel revascularization (4.5% vs 6.7%, p=0.21). Late stent thrombosis (combination of angiographic document thrombosis and thrombotic clinical events) occurred in 2.6% of the drug-eluting stent group and 1.3% of the bare metal stent group (p=0.23). The median time of the late thrombotic event was 116 days following clopidogrel discontinuation, but events occurred throughout the one year follow-up (range 362 days).

This is a very important finding. DES were invented to avoid restenosis. Restenosis does not kill. But late stent thrombosis, after the discontinuation of clopidogrel, can cause myocardial infarctions and death. Therefore those of us who implant DES must take note of this. How long then do we have to continue clopidogrel? Clopidogrel is not exactly cheap. Looks like DES is one important reason to use plavix for years. How long?? Is DES a good invention exchanging restenosis (repeat target lesion revascularisation) with heart attacks and potential death?

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