Background: Plasma exchange (PE) is used to treat severe episodes of CNS demyelination unresponsive to corticosteroids. Predictors of long-term response are not well known.
Methods: We retrospectively reviewed the medical records of 41 patients consecutively treated by PE between January 1995 and July 2007. The primary outcome was improvement at 6 months after PE defined as decrease of >or=1 point in the Expanded Disability Status Scale (EDSS) score for patients with EDSS <or=7.5 or 1.5 points with EDSS >or=8.0 or improvement of more than 2 lines in the visual acuity chart for patients with optic neuritis (ON).
Results: Twenty-five patients (61%) were women, and the median age was 33 years (range 14-57 years). Twenty-three (56%) had multiple sclerosis, 2 (5%) had clinically isolated syndrome, 2 (5%) had Marburg disease, 7 (17%) had acute disseminated encephalomyelitis, 4 (10%) had neuromyelitis optica, 2 (5%) had idiopathic ON, and 1 (2%) had idiopathic transverse myelitis. The median EDSS score before the attack was 1.0 (range 0-6.5). At PE onset, the median EDSS score was 7.0 (range 3.0-9.5). Sixteen patients (39%) improved at discharge, and 26 (63%) improved at 6 months. In the multivariate analysis, early initiation of PE (odds ratio [OR] 6.29, 95% confidence interval [CI] 1.18-52.96) and improvement at discharge (OR 7.32, 95% CI 1.21-44.38) were significantly associated with response at 6 months.
Conclusions: Plasma exchange (PE) was associated with clinical improvement in 63% of patients at 6 months. Early initiation of PE and improvement at discharge were predictors of this response. Twelve patients (48%) who did not improve early did so during follow-up.