HMOX1 and coronary artery disorder: Furthermore, HO-1 levels in the 4 groups of CAD(−), 1-VD, 2-VD, and 3-VD were 0.35, 0.49, 0.44, and 0.44 ng/mL, respectively, and HO-1 levels were highest in the 1-VD group (P < 0.05) (Figure 2).