title: Does nickel allergy play a role in the development of in-stent restenosis?
abstract: OBJECTIVE
  It was suggested that coronary in-stent restenosis might be triggered by allergy to nickel and molybdenum ions released from stainless-steel stents. We sought to explore any possible relationship between nickel allergy and in-stent restenosis.
  
  
  METHODS
  50 patients were studied, who underwent elective follow-up coronary angiography for recurrent symptoms after prior coronary stenting, at least 3 months following the index procedure. Consecutively, we enrolled 25 patients with > or = 50% in-stent restenosis (study group), and 25 others with < 50% restenosis (control group), as revealed by coronary angiography. Evaluation for nickel allergy was performed using 5% nickel sulphate solution in petroleum applied as a patch test to the interscapular region by the Finn chamber method. A positive test was defined as an inflammatory response with erythema, edema, papulovesicles, or infiltration after 48 or 72 hours.
  
  
  RESULTS
  The mean age of the whole study cohort was 55.9 +/- 13.9 years, 44 (88%) being males. Two patients of the study group (8%) had a history of contact allergy to metals. However, both of them showed a negative patch test result. No patient in the control group had a history of metal allergy (p > 0.05). Only one patient in the study group (4%) had a positive patch test result for nickel contact allergy, whereas all patients in the control group had a negative result (p > 0.05).
  
  
  CONCLUSIONS
  Based on the available evidence, a cause-effect relationship between nickel allergy and in-stent restenosis cannot be confirmed.
authors.affiliation: Department of Cardiology, School of Medicine, Ain Shams University, Cairo, Egypt.
authors.forename: R
authors.initials: R
authors.lastname: El-Mawardy
authors.forename: H
authors.initials: H
authors.lastname: Fuad
authors.forename: Z
authors.initials: Z
authors.lastname: Abdel-Salam
authors.forename: M
authors.initials: M
authors.lastname: Ghazy
authors.forename: W
authors.initials: W
authors.lastname: Nammas
mesh_terms: D000368:Aged; D015331:Cohort Studies; D017023:Coronary Angiography; D005260:Female; D006083:Graft Occlusion, Vascular / Q000209:etiology*; D006801:Humans; D006965:Hyperplasia / Q000209:etiology; D006967:Hypersensitivity / Q000150:complications* / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D009532:Nickel / Q000009:adverse effects*; D012189:Retrospective Studies; D012882:Skin Tests; D013193:Stainless Steel; D015607:Stents / Q000009:adverse effects*
chemical_list: D013193:Stainless Steel; D009532:Nickel