High risk of stent thrombosis in the first 6 months after coronary stenting

OBJECTIVES: To estimate the incidence of stent thrombosis (ST) after early discontinuation of clopidogrel. BACKGROUND: Premature discontinuation of clopidogrel is the strongest risk factor for ST. In contrast, recent studies suggest that shorter dual antiplatelet therapy (DAPT) can be discontinued as soon as 3 months after stenting. However, these studies included very few ACS patients and were not powered for ST. Hence, little is known about the occurrence of ST in high-risk populations when DAPT is discontinued early. METHODS: This is a subanalysis of The Dutch ST Registry 437 ST cases (mainly first-generation DES and BMS). Acute coronary syndrome was the indication for index-PCI in 74% of the patients. Clopidogrel discontinuation rates in ST patients and matched controls were used to calculate the absolute incidence of ST after early clopidogrel discontinuation. RESULTS: The overall rate of ST after cessation of clopidogrel was 4.6% (95%CI: 3.9-5.4%), as compared to 1.7% (95%CI: 1.5-1.9%) in patients who did not discontinue clopidogrel. The incidence of ST was 35.4% when clopidogrel was discontinued in the first 30 days after index-PCI declining to 11.7% when clopidogrel was discontinued in the first 180 days. CONCLUSIONS: This dedicated ST registry shows that ST rates were very high when clopidogrel was discontinued before 6 months after index-PCI and therefore suggests that clopidogrel discontinuation in the first 6 months after ACS should be avoided.