Prolonged double antiplatelet therapy in a cohort of "de novo" diabetic patients treated with drug-eluting stent implantation

Diabetes mellitus (DM) accounts for >25% of all percutaneous coronary interventions. In patients with DM, drug-eluting stent implantation is associated with a reduced risk of restenosis and target lesion revascularization. However, concern has been raised about the incidence of late and very late stent thrombosis and the increased mortality rate, mostly after thienopyridine withdrawal. We evaluated the long-term prognostic effect of thienopyridine discontinuation after drug-eluting stent implantation on the subsequent occurrence of stent thrombosis and all-cause death among a cohort of high-risk "de novo" diabetic patients. From May 2002 to December 2005, 542 consecutive patients with DM underwent drug-eluting stent implantation at 2 hospitals in Milan, Italy. For study purposes, only the 217 patients who had not previously undergone percutaneous or surgical revascularization were considered in the final analysis. The follow-up time was curtailed at 3.5 years. Detailed information about dual antiplatelet therapy (DAT) were collected for all patients included. Of the 217 patients, 15 died (6.9%); in 9 cases, the cause of death was cardiac (4.1%). The incidence of cumulative stent thrombosis was 4.6% (10 patients); 3 stent thromboses were early (1.38%), 5 late (2.3%), and only 2 were very late (0.9%). Of the 10 cases of stent thrombosis, 5 were definite and 5 were probable. Most (80%) of the stent thromboses occurred within the first 6 months during DAT. The median duration of DAT was 420 days (interquartile range 350 to 859). DAT discontinuation was the only independent predictor of the follow-up events (hazard ratio 20.42, 95% confidence interval 4.99 to 83.62). In conclusion, DM remains an independent adverse factor on clinical outcome. In this setting, prolonged DAT, even beyond that recommended in the guidelines, might be beneficial.