Electrophysiological Assessment of Ulnar Nerve Function After Proximal and Distal Transulnar Coronary Angiography

Background: Transulnar access has emerged as a feasible alternative to transradial access for coronary angiography. However, the electrophysiological effects of proximal and distal transulnar approaches on ulnar nerve function remain insufficiently characterized. This study aimed to compare electrophysiological changes following proximal and distal transulnar coronary angiography and to evaluate their association with ulnar nerve involvement. Methods: This single-center retrospective observational study included 97 patients who underwent proximal (n = 56) or distal (n = 41) transulnar coronary angiography and developed post-procedural pain and/or paresthesia. Electroneuromyography and nerve conduction studies were performed before the procedure and at the fourth post-procedural week. Sensory and motor amplitudes, conduction velocities, and delta (Δ) changes were compared between groups. Generalized estimating equation analysis was additionally performed to evaluate longitudinal electrophysiological changes after adjustment for demographic and procedural variables. Results: No significant between-group differences were observed in pre- or post-procedural electrophysiological parameters. Although significant reductions in right ulnar sensory amplitude were observed over time, only 4 patients (4.1%) demonstrated post-procedural ulnar sensory amplitudes below the laboratory reference range, and no patient developed clinically significant ulnar neuropathy. Comparison of electrophysiological changes (Δ values) revealed no significant differences between proximal and distal transulnar access techniques. Generalized estimating equation analysis, adjusted for age and procedural characteristics, confirmed that the magnitude of electrophysiological changes over time was comparable between the two groups. Conclusions: Both proximal and distal transulnar access may be associated with mild, predominantly sensory, subclinical ulnar nerve involvement. However, distal transulnar access did not result in greater electrophysiological deterioration or additional neurological risk compared with proximal access.