The causes of ‘early’ and ‘late’ stent thrombosis are now mostly understood, making these events much easier to prevent than ‘very late’ thrombosis, an international expert says.
Speaking at the CSANZ 2011 59th Annual Scientific Meeting in Perth last week, Associate Professor Don Cutlip, Director of the Cardiac Catheterization Laboratory at Beth Israel Deaconess Medical Center in Boston, Massachusetts, US, said early and late stent thrombosis represented about 50% of all stent thrombosis cases.
The risk of these events was “mostly due to procedure and mechanical factors and dual-antiplatelet therapy compliance” he said.
“We know much more about the risk factors and probably have a better chance of preventing these events than we do in some cases of the very late stent thrombosis.”
Findings from the Dutch Stent Thrombosis Registry showed stopping clopidogrel (Plavix) within the first 30 days was the most important predictor of developing early and late stent thrombosis (HR: 36.53), followed by stent under sizing and thirdly, stopping clopidogrel within the first six months, he said.
Professor Cutlip also analysed practice implications in light of the US Food and Drug Administration’s (FDA’s) boxed warning on clopidogrel highlighting reduced effectiveness of the drug in ‘poor metabolisers’.
He concluded that optimal screening for those patients and alternative therapies remained uncertain, particularly in patients with stable coronary disease.
Prasugrel could be used as an alternative in patients with acute coronary syndrome (ACS), especially younger patients, he suggested. He cautioned however, that it was linked with increased risk of major bleeding compared with clopidogrel.
Lower risk of stent thrombosis was also associated with second generation everolimus-eluting stents and zotarolimus-eluting stents versus paclitaxel-eluting stents, he said.
Professor Cutlip said future research would be required to assess the risk of stent thrombosis with newer devices including bio-absorbable polymers and stents.