Carotid-femoral pulse wave velocity ( PWV ) was measured with aplanation tonometry ( Sphygmocor ) after 8 ( W8 ) and 24 weeks ( W24 ) of treatment by the single-pill combination valsartan-amlodipine ( 80/5 mg , then 160/10 mg ) or an atenolol-amlodipine combination ( 50/5 mg , then 100/10 mg ) in a prospective , randomized , parallel-groups multicenter trial with PROBE design .