Lp(a) lipoprotein as a risk factor for coronary heart disease and cerebral infarction.

Attempts were made to prepare antisera monospecific for Lp(a) lipoprotein and to investigate the distribution of subjects according to plasma levels of Lp(a) in Japanese controls and patients with coronary heart disease or cerebral infarction. Positive plasma reactions to the double diffusion test for Lp(a) (Ouchterlony) were observed in 32.3% of the healthy Japanese subjects, which is similar to results previously reported in western countries. The plasma threshold level of 17 mg/dl was considered an appropriate point for dividing subjects into positive and negative groups depending on reactions to the double diffusion test. When subjects were divided into two groups at 17 mg/dl, a significant association was found between a high plasma level of Lp(a) and either coronary heart disease or cerebral infarction in the distribution of the cortical artery. These results suggest that Lp(a) may play an important part as a risk factor for coronary heart disease and cerebral infarction.