• The primary outcome measure is Pulse Wave Velocity. [ Time Frame: The time frame is 5 months ] [ Designated as safety issue: No ]
  

• The secondary outcome measures are Augmentation Index (AIx) and Forced Expiratory Volume in 1 second (FEV1) [ Time Frame: The time frame is 5 months ] [ Designated as safety issue: No ]
  

This is a multicenter, randomized, double-blind, placebo controlled study to evaluate the effect of Fluticasone Propionate/Salmeterol DISKUS 250/50mcg (FSC) BID on arterial stiffness in COPD subjects. Following a 1 to 14 day run-in period, approximately 250 subjects will be randomly assigned to double-blind treatment for 12 weeks. After the 12 week treatment period, subjects in both treatment arms will receive open label Tiotropium bromide Handihaler18mcg (Tio)QD for 4 weeks in addition to their continued study drug (either FSC250/50 or placebo). The primary measure of efficacy is Pulse Wave Velocity (PWV) at Endpoint. Secondary efficacy measures include Augmentation Index (AIx), Biomarkers of cardiovascular disease, measures of lung function. (e.g. FEV1). Safety will be assessed through the collection of adverse events and COPD exacerbations. Exploratory endpoints include the effect of Tiotropium on PWV and AIx when added to placebo or FSC. Treatment groups will be stratified based on current smoking status. There will be a total of 6 study visits (screening, randomization, and after 4, 8, 12 and 16 weeks of treatment). A follow-up phone contact for collection of adverse event and pregnancy information (if applicable) will be conducted approximately 14 days following the last study visit.