Shinsato et al. 2010 and Tei et al. 2007 compared VAS for leg pain as well as 6 MWD (6-minute walking distance), ABI (ankle/brachial index), leg blood flows with Doppler laser imaging and angiography, gene expression levels of CD34+ blood cells and serum levels of VEGF, and nitrates and nitrites in patients hospitalised with peripheral artery disease [34, 45]. Here, CD34 is linked to peripheral arterial disease.