This is consistent with previous studies showing increased circulating EPCs in acute myocardial infarction and stroke [29,30], and with the observation that the number of EPCs CD45+CD34+KDR+ was negatively related to FMD value, which confirms the potential interaction between EPCs CD45+CD34+KDR+ and endothelial damage and dysfunction. Here, CD34 is linked to acute myocardial infarction.