RESULTS	Following CAS , PSV gradually increased during follow-up , whereas PSV remained relatively stable after CEA ; mean difference of PSV between CAS and CEA : 23 cm/s ( 95 % CI , -5 to 52 ) , 58 cm/s ( 95 % CI , 27-89 ) , and 69 cm/s ( 95 % CI , 31-107 ) at 30 days , 12 months , and 24 months .\