This is a randomized 1:1, two arm, single-blind, single-site, parallel group, post-marketing comparison study of the effects on antithrombotic biomarkers of aliskiren 150-300mg/day alone vs combined treatment with aliskiren 150-300mg/day plus valsartan 160mg/day over a four week primary treatment period. An optional four week extension phase may be offered pending assessment of the antithrombotic biomarker assays at week four.