Isovolemic Erythrocytapheresis; Fixed Versus Patient Tailored Volume Exchange in Patients with Polycythemia or Hemochromatosis.
Authors: Wijermans P.W. , van Egmond L. , Ypma P.F. , Schipperus M.R. , Kerkhoffs Jean-Louis , Bohmer L.H. 
Published: April 2020

Abstract
Introduction: Conventional phlebotomy is the standard therapy to remove either erythrocytes or iron in patients with Polycythema Vera (and sec. polyglobulinemia) or patients with hemochromatosis (HC) (and iron overload). This treatment that should be repeated regular has its side effects, is often experienced as inconvenient by the patients and the desired effect is not always reached. We developed an erythrocytapheresis technique based on an isovolemic principle that can be used to remove larger amounts of erythrocytes and is experienced as more convient by the patients. Here we report our experience and compare conventional phlebotomy with either a removal of a the fixed volume of 500 ml or with an exchange volume based on a decrease in Ht ordered by the haematologist.
Technique: The erythrocytapheresis was performed according to the standard procedure using a Cobe Spectra. The establish an isovolmic procedure the removed erythrocyte volume was replaced by albumin and ACD anticoagulant with either a volume of 500ml or with a calculated volume to reach the desired Ht.
Patients: 29 patients (14 male, 15 female) were entered in this study with a median age of 57 years (range 20–80years). 14 patients were diagnosed as PV patients, 10 with HC, 4 with sec. polyglobulinemia and 1 with sec. iron overload. In 10 patients this therapy was started for reasons of intolerance or insufficient result of repeated phlebotomy. In 19 patients it was used as front line therapy before cytoreductive treatment was started or as supportive care.
Results: A total number of 137 procedures were performed. 105 with a fixed volume of 500 ml and 32 with a calculated volume based on the desired decrease of the Ht. The maximum number of procedures was 22 in a patient with phlebotomy resistant HC. All procedures were performed without any clinical problems and experienced as more convenient by those patients who could compare these techniques.
In 14 PV patients 47 procedures were performed with a median removal of 16% of the total erythrocyte volume. Compared with conventional phlebotomy this was an improvement in 12 patients with a median increase in erythrocyte removal of 58% (range −14%–81%). In the 10 HC patients 69 procedures with median erythrocyte volume removal of 535 ml was performed. This was a median removal of 22% (range 17–24%) of the total erythrocyte volume and an improvement of median 140% (range 65–216%) compared with phlebotomy. In the other 5 patients the median removed volume was 13% (11–16%) with an improvement of 13% (range 11–16%).
The erythrocyte volume removed with the patient tailored volume exchange were all within the range of the volumes removed with the fixed exchange volume technique.
Conclusions: Isovolemic erythrocytapheresis is a save and efficient technique either to removed large volumes of erythrocytes or to treat iron overload. Patient tailored volume removal is as yet not more efficient as the fixed volume procedures. Probably this technique can be improved further both technically and by removal larger amounts of erythrocytes.