Nickel-Free Drug-Eluting Stents
Yes, there are current drug-eluting stents that are nickel-free or have negligible nickel release, specifically those made from cobalt-chromium or platinum-chromium alloys rather than stainless steel.
Stent Platform Materials and Nickel Content
Modern drug-eluting stents have evolved significantly in their platform materials 1:
- First-generation stents were predominantly made from 316L stainless steel, which contains nickel as a major component 2
- Second-generation stents utilize cobalt-chromium or platinum-chromium alloys with improved strut design 1
- Bare-metal stents are composed of either stainless steel (nickel-containing) or cobalt-chromium alloys (minimal to no nickel) 3
Clinical Significance of Nickel in Stents
The nickel concern has two important clinical contexts:
Nickel allergy prevalence: Approximately 19% of patients undergoing stent implantation test positive for nickel allergy 2. Among patients with chronic refractory in-stent restenosis, 30% were nickel-positive compared to only 9% in those without recurrent restenosis 2.
Actual nickel release is negligible: Recent laboratory testing demonstrates that nickel release from modern intracranial stents (which share similar alloy compositions with coronary stents) is undetectable even after 30 days of incubation in plasma-like media 4. This suggests that previously reported hypersensitivity reactions may be misattributed to nickel allergy 4.
Practical Recommendations
For patients with documented nickel allergy:
- Select drug-eluting stents with cobalt-chromium or platinum-chromium platforms rather than stainless steel platforms 1
- The clinical risk from nickel-containing stents appears lower than historically believed, as nickel release is negligible 4
- Nickel allergy remains a significant predictor of chronic refractory in-stent restenosis (odds ratio 5.41) 2, justifying avoidance when alternatives exist
Alternative hypersensitivity considerations:
Drug-eluting stents contain five potential antigens beyond the metal platform: polymer coating, eluted drug, and concomitant medications (clopidogrel and aspirin) 5. Hypersensitivity reactions can manifest as Kounis syndrome with acute coronary events 5.
Current Stent Options
Second-generation drug-eluting stents with non-stainless steel platforms include 1:
- Everolimus-eluting stents (cobalt-chromium or platinum-chromium platforms)
- Zotarolimus-eluting stents (cobalt-chromium platforms)
- Newer biolimus-eluting stents with biocompatible or biodegradable polymers
These platforms demonstrate superior vascular healing responses and lower thrombotic events compared to first-generation stainless steel stents 1.