Background

An allergy to nickel metal is a common occurrence in the population, with a greater distribution amongst female patients. This can lead to difficulty in the management of intracranial aneurysms in these patients given that many aneurysm treatment devices are manufactured with nickel alloys, such as nitinol. Previously it has been reported that neurological injury may be attributed to these nickel based devices. In the context of patients with a suspected nickel based allergy, recommendations have been to undertake formal allergen testing and/or consider the use of devices which do not contain nickel although this can limit therapeutic options for patients. Although it has been purported that the nickel release from intracranial stents is negligible and that patients with an allergy may be safely treated with select nickel-containing devices

Objective

Our objective was to determine the outcomes of patients who have an allergy to nickel by undertaking a trial of stenting in an upper limb vessel with a nickel based stent, with follow-up assessment to assess for complications such as in-stent stenosis. If no complications developed in the upper limb stent, then these patients would then proceed to management of their intracranial aneurysms with a nickel based device.

Methods

Inclusion criteria were: endovascular and transcather procedures for neurovascular pathology involving nickel-allergic patients over a 10 year period. Retrospective analysis was undertaken to assess the outcomes following both the peripheral upper limb vessel and intracranial vessel stenting.

Results

Over a 10 year period, there were 7 patients who met the inclusion criteria for the study. Of these 7 patients, 4 had an ulnar stent implanted, while the remainder had a radial stent. These patients were either followed up with clinical examination at the site of stent implantation or focused ultrasound to assess stent patency. No patient developed in-stent stenosis or occlusion. These patients then went on to have their neurovascular interventions for aneurysm treatment, with no immediate or post-procedure complications. To date, these patients follow-up imaging continues to show good flow through stented vessels and no aneurysm recurrences.

Conclusions

This study highlights that in patients with a nickel allergy who require aneurysm treatment, undertaking stenting of an upper limb vessel prior to their subsequent intracranial aneurysm treatment is a viable therapeutic option.