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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 29, No 1, January/February 2018
AFRICA
43
Coronary stent restenosis and the association with
allergy to metal content of 316L stainless steel
D Slodownik, C Danenberg, D Merkin, F Swaid, S Moshe, A Ingber, H Lotan, R Durst
Abstract
Background:
Most intra-coronary stents in use are made of
316 L stainless steel, which contains nickel, chromate and
molybdenum. Whether inflammatory and allergic reactions
to metals contribute to in-stent restenosis is still a matter of
debate.
Aim:
The aim of this study was to ascertain the relationship
between metal allergy and the occurrence of in-stent reste-
nosis.
Methods:
Ninety-nine adult patients who underwent two
cardiac catheterisations, up to two years apart, were included
in the study. Seventy patients had patent stents at the second
angiogram (patent stent group) and 29 were found to have
in-stent restenosis (restenosis group). All patients underwent
patch testing with the relevant metals and the 316L stainless
steel plate.
Results:
Twenty-eight (28.3%) patients were found to have an
allergy to at least one metal. There was no significant differ-
ence in the prevalence of metal allergy between the patent
stent group and the restenosis group (28.6 and 27.6%, respec-
tively;
p
=
0.921).
Conclusion:
Our data do not support the theory that contact
allergy plays a role in the pathogenesis of in-stent restenosis.
Keywords:
stent restenosis, metal allergy, stainless steel
Submitted 14/2/17, accepted 13/7/17
Cardiovasc J Afr
2018;
29
: 43–45
www.cvja.co.zaDOI: 10.5830/CVJA-2017-036
Risk factors for in-stent restenosis, such as diabetes mellitus,
diameter of the treated artery, length of the lesion and localisation
are well known. In-stent restenosis (ISR) results from excessive
fibroproliferative and inflammatory responses to the insult on
the arterial wall, leading to neo-intimal proliferation.
Hypersensitivity reaction to metals may be part of the
inflammatory process and one of the triggering factors in ISR.
1
Contact allergy is a common health concern worldwide, with an
estimated 15 to 20% of Western populations being hypersensitive
to at least one metal allergen.
2
Recently, much progress has
been made regarding the mechanisms underlying inflammatory
responses to this unique group of contact allergens, including
innate immune activation and T-cell activation by common
metal allergens, such as nickel, cobalt, palladium and chromate.
3
Koster and co-workers
1
were the first to demonstrate a higher
incidence of ISR in patients with delayed hypersensitivity to
metals, especially to nickel and molybdenum. Two years later,
Hillen
et al
.
4
published a study that showed no significant
differences in the incidence of restenosis in patients with
hypersensitivity to metals, compared to patients without
hypersensitivity to metals. Similarly, Iijima
5
demonstrated that
metal allergy was not associated with restenosis after initial stent
implantation. However, metal allergy was frequently observed in
patients with ISR recurrence.
Given the impact of ISR on coronary patient morbidity and
mortality rates, and given the contradictory data available in the
current literature, we conducted a case–control study aimed at
identifying an association between metal allergy and ISR.
Methods
An informed, written consent was obtained from all patients.
The study received the approval of the local institutional review
board for human research.
Ninety-nine patients aged 18 years and older, who underwent
at least two coronary artery catheterisations within a period
of two years at the Department of Cardiology, Hadassah
University Hospital in Jerusalem, were enrolled into the study. A
bare-metal stent was implanted in one coronary vessel during the
first catheterisation. The second catheterisation was performed
to assess the degree of restenosis.
Catheterisation was performed, using the Seldinger technique,
through the femoral artery with 6F standard catheters. In case of
intervention, a guiding catheter was introduced over a wire. Stent
implantation was usually performed after balloon predilatation.
Patients were divided into two groups as follows. The study
group consisted of 29 patients who underwent implantation of
at least one stent at the first catheterisation and were found to
have ISR during the second catheterisation. The control group
consisted of 70 patients who underwent implantation of at least
one stent at the first catheterisation and were found to have a
patent lumen during the second catheterisation.
The presence or absence of ISR was determined by the
cardiologists who performed the catheterisation. Significant
stenosis was defined as stenosis of 50% or more of the coronary
Department of Dermatology, Hadassah Hebrew University
Medical Centre, Jerusalem, Israel
D Slodownik,MD,
dans@tlvmc.gov.ilF Swaid, MD
A Ingber, MD
Cardiology Division, Hadassah Hebrew University Medical
Centre, Jerusalem, Israel
C Danenberg, MD
D Merkin, MD
H Lotan,MD
R Durst,MD
Sackler Faculty of Medicine, School of Public Health,
Department of Environmental and Occupational Health, Tel
Aviv University, Tel Aviv, Israel
S Moshe, MD