KYOTO, JAPAN — Contact sensitivity to nickel may play an etiologic role in a subset of cases of in-stent restenosis involving bare metal coronary stents.
A positive reaction to nickel was documented in 10 of 78 patients who underwent patch testing to a series of metals, as well as clinically driven quantitative coronary angiography, a median of 9 months after placement of one or more bare metal stents, according to Dr. Golara Honari.
The patch test-positive group had a “modestly” but nonetheless significantly greater lumen loss in the stented segment than did the patch test-negative patients. The mean lumen loss in the 13 stented segments placed in nickel-sensitive patients was 1.1 mm, compared with 0.69 mm in 100 stented segments in patients who had negative reactions, Dr. Honari of the Cleveland Clinic Foundation reported at an international investigative dermatology meeting.
The association between lumen loss and a positive patch test to nickel remained significant in a multivariate linear regression analysis controlling for known risk factors for in-stent restenosis, including diabetes, smoking, and stent length.
Other metals included in the patch test series were chromium, cobalt, molybdenum, and manganese, all of which are commonly used in stents and other cardiovascular devices. No significant associations were found between lumen loss or other angiographic end points and positive reactions to these other metals.
The hypothesis is that contact sensitivity to the nickel present in a bare metal stent may increase the endovascular inflammatory response to the device, resulting in an increased risk of in-stent restenosis. Further investigation is warranted before researchers draw any definitive conclusions, Dr. Honari said at the meeting of the European Society for Dermatological Research, the Japanese Society for Investigative Dermatology, and the Society for Investigative Dermatology.