New Hydrophilic Helixone Dialyzers as an Alternative for Hemodialysis Patients With Membrane Hypersensitivity Reactions: A Retrospective Single-Cohort Study

Synthetic dialysis membranes, particularly those composed of polysulfone blended with polyvinylpyrrolidone, are commonly used in hemodialysis due to their efficiency. However, hypersensitivity reactions-often atypical and not fitting traditional type A and B classifications-have increasingly been reported. Symptoms include chest tightness, bronchospasm, oxygen desaturation, and hypotension, often without clear etiology. The need for safer alternatives has led to interest in newer dialyzer technologies, such as the hydrophilic helixone membrane which incorporates tocopherol to enhance biocompatibility.

We conducted a multicenter, retrospective observational study in four hemodialysis units in Catalonia (Spain). Thirty-one stable patients previously diagnosed with hypersensitivity to synthetic membranes and dialyzing with cellulose triacetate were switched to hydrophilic helixone (CorAL) dialyzers. Clinical data, including symptoms before and after the switch, were extracted from medical records. The primary outcome was the occurrence of adverse reactions after the transition.

Of the 31 patients (mean age 70.1 ± 13.9 years), the most common symptoms at initial reaction included cutaneous (21, 67.7%), respiratory (13, 41.9%), and cardiovascular (9, 29.0%) manifestations. After switching to hydrophilic helixone, 28 patients (90.3%) had no further hypersensitivity symptoms over a mean follow-up of 5.8 ± 4.3 months. Three patients experienced mild reactions (two with pruritus, one with hypotension) and reverted to cellulose triacetate. No significant associations were found between relapse and the type of membrane or symptom profile.

The hydrophilic helixone membranes appear to be a safe and well-tolerated alternative for patients with a history of hypersensitivity to synthetic membranes. These findings suggest that hydrophilic helixone dialyzers may allow more patients to continue treatment with synthetic membranes without severe reactions, potentially improving biocompatibility and treatment flexibility in routine clinical practice. While the findings are promising, larger prospective studies are necessary to confirm the safety and long-term clinical benefits.