Beneficial effects of plasmapheresis before thymectomy on the outcome in myasthenia gravis

Since 1980, we have performed plasmapheresis before thymectomy for patients with generalized symptoms in order to protect against myasthenic crisis and to improve patient outcomes after thymectomy. The aim of this study was to evaluate an immediate and a long-term results of plasmapheresis before thymectomy for myasthenia gravis, retrospectively.

Between January 1980 and December 1997, 51 patients with Osserman class IIA or IIB symptoms were treated with transsternal thymectomy. Nineteen patients (group 1) were treated with plasmapheresis before thymectomy and 32 patients (group 2) were treated with thymectomy alone.

In group 1, the time of plasmapheresis prior to thymectomy was 3.2 +/- 1.5. Nine (28.1%) patients in group 2 had crisis within 1 year after thymectomy as compared with only one (5.3%) patient in group 1 had crisis (p = 0.049). There was no evidence of crisis within 30 days after thymectomy in group 1 and 5 (15.6%) patients in group 2 (p = 0.0724). There was no postoperative death among patients in group 1. Responses to thymectomy in group 1 improved significantly, the improvement and pharmacologic remission rate had increased up to 100% and 79% at 5-7 years after operation, while the improvement and pharmacologic remission rate of group 2 had increased to 81.3% (p = 0.0466 vs. group 1) and 50.0% at that time (p = 0.0427 vs. group 1).

The present study demonstrated that preoperative plasmapheresis may facilitate improved outcomes of patients with myasthenia gravis after thymectomy.