Plasma Exchange Therapy
Carol L. Koski, M.D., Principal Author
Plasma exchange (PE) or plasmapheresis is a process in which the plasma is removed from blood cells by a cell separator. The separator works either by using a continued flow centrifuge system or a membrane filtration device to separate the plasma from cellular blood components.
With either system, the cells are returned to the person undergoing treatment, while the plasma, which contains the antibodies, is discarded and replaced with other fluids. An anticoagulant to prevent clotting is given during the procedure.
Dosing and Tolerability
Plasma exchange treatment takes several hours and can be done on an outpatient basis. However, the procedure is not performed at all hospitals across the country. It is more commonly done at the major medical centers with a specialized plasmapheresis team.
Plasma exchange can be uncomfortable but is normally not painful. The number of treatments needed varies greatly depending on the particular disease and the person's general condition.
Typically, plasma exchange therapy for CIDP is initiated at 2-3 treatments per week for a total of 5-6 treatments with periodic re-treatment, if required. Clinical improvement can occur within days and tends to last for 3 to 4 weeks. Two small double blind randomized clinical trials with a total of 47 patients enrolled (Dyck, 1986; Hahn, 1996; Mehndiratta, 2004) showed that plasmapheresis provides significant short-term benefit in about two-thirds of patients, but rapid deterioration may occur afterwards.
The results from three randomized crossover trials showed that plasma exchange performed twice weekly over 3 to 6 weeks produced a temporal improvement in neurologic disability score, nerve conduction velocity and grip strength in 80% of patients within 2 to 3 weeks. However, the improvements were lost within 7 to 14 days when plasma exchange was discontinued. (Dyck, 1994, Dyck, 1996; Hahn, 1996)
The procedure is usually well tolerated but complications can include cardiac arrhythmia from an electrolyte imbalance, citrate-induced hypocalcemia, and hemolytic anemia. Many patients require a surgically placed central catheter which may become infected or develop clots. The procedure requires large bore intravenous catheters placed into central veins and repeated venous access can lead to venous stenosis and thrombosis at the site of venous access. (Ropper, 2003) In addition, the patient, rarely, may experience allergic reactions leading to and activation of coagulation, complement and fibrinolytic cascades, as well as platelet aggravation.
Because of adverse events related to difficulty with venous access, the use of citrate, and the hemodynamic changes that occur with plasma exchange therapy, the EFNS/PNS joint task force recommends that either IGIV or corticosteroid therapy be considered prior to plasma exchange. (Joint Task Force, 2005)
Plasmapheresis might be considered as an initial treatment for CIDP but not for long term treatment of CIDP. (Joint Task Force, 2005)
