Angiotensin-converting enzyme insertion/deletion polymorphism does not influence the restenosis rate after coronary stent implantation

Background. Experimental studies have shown an activation of the
angiotensin-converting enzyme (ACE) system as a response to
endothelial injury. Recent publications have elucidated the
hypothesis that the ACE gene polymorphism may influence the level
of late luminal loss after coronary stent implantation. It is still
unclear whether the polymorphism of the angiotensin gene is a major
predictor of the extent of neointimal hyperplasia. In this
multicenter study, we therefore tested the relationship between the
ACE gene polymorphism and the restenosis rate after coronary stent
implantation. Methods: As a substudy of the optimization with
intracoronary, ultrasound (ICUS) to reduce stent restenosis
(OPTICUS) study, we analyzed ACE serum levels and the ACE gene
polymorphism in 154 patients at 9 different centers. All patients
underwent elective coronary stent implantation in a stenosis of a
major coronary vessel. Balloon inflations were repeated until a
satisfactory result was achieved in on-line quantitative coronary
angiography or ICUS fulfilling the OPTICUS study criteria. After
follow-up of 6 months, all patients underwent reangiography tinder
identical projections as the baseline procedure. A blinded
quantitative analysis of the initial procedure as well as the
follow-up examinations were performed by an independent core
laboratory. ACE gene polymorphism and ACE serum activity were
measured at the 6-month follow-up in a double-blinded setting.
Results: With respect to the ACE gene polymorphism, there were
three subgroups: DID genotype (48 patients), ID (83 patients) and
11 (23 patients). The subgroups did not differ in regard to age,
gender, extent of coronary artery disease, stenosis length, initial
degree of stenosis or degree of stenosis after stent implantation.
In all, 39 patients (25.3%) had significant restenosis: 12 DD
patients (25.0%), 18 ID patients (21.7%) and 9 II patients (39.1%)
(odds ratio 2.164, 95% confidence interval 0.853-5.493). We
obtained the following results for ACE serum levels: 0.53 mumol/l/s
in the DD subgroup, 0.29 mumol/l/s in the ID.