Continued treatment with thienopyridine , as compared with placebo , reduced the rates of stent thrombosis ( 0.4 % vs. 1.4 % ; hazard ratio , 0.29 [ 95 % confidence interval { CI } , 0.17 to 0.48 ] ; P < 0.001 ) and major adverse cardiovascular and cerebrovascular events ( 4.3 % vs. 5.9 % ; hazard ratio , 0.71 [ 95 % CI , 0.59 to 0.85 ] ; P < 0.001 ) .