Stent implantation in patients with metal allergy: a systemic review and meta-analysis

The aim of this study was to assess whether outcomes of patients with metal allergy after coronary stent implantation differ from those of patients without metal allergy.

A meta-analysis was carried out to compare the outcome in patients who are allergic to the metal material of a stent with those who are nonallergic. A computer-based online retrieval of databases and manual searches were performed to identify articles that addressed the association between in-stent restenosis (ISR) and contact allergy to stent materials, without language restrictions. The meta-analysis was carried out with a fixed-effect model using STATA 11. Odds ratio (OR) was used as an effect size.

Nine relevant articles, encompassing 1223 patients, were identified. Being allergic to stent material obviously increased the risk of ISR. With the fixed model, ORs for allergic patients and nonallergic patients were 2.65 (confidence interval 1.82-3.82). A subgroup analysis of race was carried out. OR in the Asian group was higher than that in the European group (3.71 vs. 2.25), which might suggest that Asians who are allergic to stent material have a higher risk of ISR than Europeans.

Allergy to stent material worsens the prognosis of patients with coronary stent implantation. New well-designed prospective clinical trials are required to confirm this relationship and to establish the indispensability of a skin patch test before coronary stent implantation.