High levels of serum lipoprotein(a) in patients with ischemic heart disease with normal coronary angiogram and thromboangiitis obliterans Original Research Article

To determine whether lipoprotein(a) (Lp(a)) contributes to the acceleration of cardiovascular diseases without atherosclerotic lesion, we have measured serum Lp(a) level in male subjects aged 40–69 years with thromboangiitis obliterans (n = 40) and ischemic heart disease (IHD) with normal coronary angiogram (n = 35) in addition to subjects with arteriosclerosis obliterans (n = 123) and IHD with atherosclerotic coronary lesion (n = 203). Cases who had no IHD, arteriosclerosis obliterans or thromboangiitis obliterans were selected as a control group (n = 316). Subjects without any diseases or abnormal findings in physical examination and laboratory data were selected from the control group as the healthy control group (n=156). The Lp(a) levels of arteriosclerosis obliterans and IHD with atherosclerotic coronary lesion were significantly higher (17.0 mg/dl and 13.1 mg/dl; median) than those of control and healthy control groups (9.9 mg/dl and 9.4 mg/dl, respectively) (P < 0.01), in agreement with previous reports. Furthermore, the Lp(a) level of IHD with normal coronary angiogram group was significantly higher (18.9 mg/dl) than those of the control and healthy control groups (P < 0.05). The Lp(a) level of thromboangiitis obliterans group was also much higher (21.3 mg/dl) than that of the healthy control group (P < 0.05). The current study suggests that Lp(a) is one of the independent risk factors for the development of atherosclerotic diseases such as arteriosclerosis obliterans and IHD with atherosclerotic coronary lesion. Furthermore, high levels of Lp(a) in cases with cardiovascular diseases without atherosclerotic lesion, such as IHD with normal coronary angiogram and thromboangiitis obliterans, suggest that Lp(a) could also contribute to the pathogenesis of cardiovascular diseases by a mechanism different from atherosclerosis.