Apolipoprotein ϵ4 homozygosity — a determinant of restenosis after coronary angioplasty

Abstract

Conventional coronary risk factors have not consistently been found to be related to restenosis after coronary angioplasty. Apolipoprotein E (apo E) gene polymorphism and/or plasma apo(a) levels were determined in 195 subjects undergoing prospective follow up and angiographic study 6 months after elective balloon angioplasty of a previously untreated coronary obstruction. Restenosis (stenosis ⩾ 50% plus loss of ⩾ 50%, of initial gain) had occurred in 59 of 150 subjects for whom E genotypes were available. The apo ϵ4 allele frequency in those with restenosis was higher than those without (0.20 vs. 0.10, P < 0.01), attributable to an excess of ϵ4 homozygotes in the restenosis group (5 of 59 vs. I of 91, P < 0.04). Restenosis was not related to plasma apo(a) and the apo ϵ4 allele was not associated with elevated levels of apo(a) as has been reported elsewhere. No relationship was found between E genotype and serum lipid and lipoprotein levels; paradoxically, LDL cholesterol was significantly lower and HDL cholesterol higher in those with restenosis. In conclusion, homozygosity for apolipoprotein ϵ4 appears to be an important determinant of restenosis after coronary angioplasty.