Thermofiltration in hypercholesterolemia treatment: analysis of removal and posttreatment cholesterol recovery

Thermofiltration, a system of membrane plasmapheresis for LDL apheresis, is used to treat patients with refractory hyperlipidemia. In this system, the separated plasma is warmed to or above physiologic temperature, filtered with a membrane filter, and returned to the patient on-line. Plasma infusion products are not required. In this study one calculated plasma volume was treated weekly, biweekly, or monthly in patients classified as type II hypercholesterolemic. Reduction and sieving of lipoproteins were evaluated. The reduction ratios of high-density lipoprotein cholesterol (HDLc) and low-density lipoprotein cholesterol (LDLc) were 0.30 +/- 0.06 and 0.58 +/- 0.05, respectively (mean +/- S.D.). Sieving coefficients of the plasma filter for HDLc and LDLc were 0.62 +/- 0.12 and 0.03 +/- 0.02, respectively (mean +/- S.D. of 31 treatments). To evaluate the posttreatment recovery the apparent fractional catabolic rates (FCRa) for total cholesterol and LDLc were calculated. FCRa was 0.151 +/- 0.06 and 0.148 +/- 0.06 day-1 for total cholesterol and LDLc, respectively. The ratio of the posttreatment concentration on the seventh day to the concentration immediately pretreatment was found to be significantly higher for HDLc than for LDLc, 0.92 +/- 0.8 vs. 0.77 +/- 0.1 (mean +/- S.D.), due to faster HDLc recovery. The ratio of LDLc/HDLc was lowered for up to 2 weeks after the treatments.