Transcatheter patent foramen ovale closure in patients with and without documented nickel hypersensitivity

Abstract Background Transcatheter PFO closure has been established as a safe and feasible approach for secondary prevention in appropriately selected patients with previous cryptogenic stroke. The two FDA-approved devices, widely used, consist of a nitinol frame; a nickel-titanium alloy. Although nickel is recognized as the primary metal causing hypersensitivity reactions worldwide, the potential occurrence of nickel hypersensitivity following PFO closure remains a subject of debate. Purpose The aim of this study is to investigate whether patients with nickel hypersensitivity are more susceptible to experiencing adverse events after PFO closure and to explore the potential role of device selection. Methods We prospectively enrolled patients undergoing PFO closure at our tertiary hospital. Before the procedure, all patients underwent nickel skin patch tests, considered the gold standard for diagnosing nickel hypersensitivity. Subsequently, patients were randomized to receive one of the two FDA-approved devices. During a three-month follow-up period, we evaluated the primary endpoint, a composite outcome including patient-reported chest pain, palpitations, headaches, and rash. Blinding was maintained for the patients, the operator, and the assessor of endpoints regarding the results of the nickel skin patch tests. The chi-squared test was utilized to evaluate the primary endpoint. Results for continuous variables are expressed as mean ± standard deviation or, for non-normally distributed variables, as median (interquartile range). Results Between January 2021 and November 2023, a total of 63 patients were included in our analysis. The majority were men (n=33, 52.4%) with a mean age of 46.1 ± 10.1 years. The median RoPE score was 7 (6-8). Nickel hypersensitivity was documented in 30.8% of the patients. The primary endpoint was met in 37.7% (n=23) of the total sample, with a significantly higher incidence in patients with nickel hypersensitivity than in those without (61.1% versus 27.9%, p=0.015, OR: 4.060, 95% CI: 1.275 – 12.930). No significant difference was observed when analyzing the two devices separately (p=0.096 and p=0.078, respectively). No recurrent ischemic stroke, severe anaphylactic reaction, or requirement for device surgical removal was observed in any patient. Conclusions Our findings indicate that patients with documented nickel hypersensitivity are more likely to develop symptoms such as chest pain, palpitations, headaches, and rash following the procedure. However, these findings do not raise major safety concerns. The completion of our study is necessary to acquire more reliable and conclusive results.