Therapeutic plasma exchange: an update from the Canadian Apheresis Group.

In 1997, the Canadian Apheresis Group reviewed data on 103,416 plasma exchange procedures that had been collected since 1980. Although the number of plasma exchanges gradually increased (from 3189 to 8208 per year), the pattern changed. In 1981, the five most frequent indications for plasma exchange resulted in 55% of all such procedures; by 1997, the five most frequent indications for plasma exchange resulted in 81.1% of all such procedures. During this period, three conditions that were originally among the most frequent indications for plasma exchange became among the least frequent. This paper reviews the published evidence that supports or refutes the use of plasma exchange in the category of the five most frequent indications from 1981 to 1997: thrombotic thrombocytopenic purpura, myasthenia gravis, chronic inflammatory demyelinating polyneuropathy, Waldenstrom macroglobulinemia, the Guillain-Barre syndrome, rheumatoid arthritis, systemic lupus erythematosus, and multiple sclerosis. For most disorders, use of plasma exchange procedures is correlated with published evidence, and the changing patterns of plasma exchange use by members of the Canadian Apheresis Group reflect published evidence. Annual center-by-center reviews of use of plasma exchange may also have influenced practice patterns.