Transfusion medicine
Apheresis
Low density lipoprotein (LDL) apheresis

Author: Huy Phu Pham, M.D., Garrett S. Booth, M.D., M.S. (see Authors page)

Revised: 3 November 2017, last major update March 2014

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed Search: Transfusion low density lipoprotein apheresis

Cite this page: Pham, H.P., Booth, G. Low density lipoprotein (LDL) apheresis. PathologyOutlines.com website. http://pathologyoutlines.com/topic/transfusionmedLDL.html. Accessed November 23rd, 2017.
Definition / general
  • LDL apheresis: removal of LDL ("bad" cholesterol) by separating whole blood into its components and then selectively removing LDL from plasma by filtration / absorption; see guidelines at Circulation 2014;129:S1
Instrumentation
Epidemiology
  • Familial hypercholesterolemia:
    • High LDL levels from birth secondary to genetic mutation in ApoB / E (LDL) receptor
    • Autosomal dominant
    • Associated with early LDL deposits in tendons forming xanthomata; also early onset coronary artery disease
    • Patients with 2 mutations have more severe disease (OMIM: HYPERCHOLESTEROLEMIA, FAMILIAL [Accessed 1 November 2017])
  • Lipoprotein(a) hyperlipoproteinemia:
  • Refsum disease:
    • Autosomal recessive disorder that results in tetrad of abnormalities:
      • Retinitis pigmentosa, peripheral neuropathy, cerebellar ataxia and elevated protein levels in cerebrospinal fluid, without an increase in the number of cells
    • Most common presenting symptom is night blindness (OMIM: REFSUM DISEASE, CLASSIC [Accessed 1 November 2017])
    • Treat by removing excess phytanic acid plus dietary modification (avoid dairy)
  • Sudden sensorneurial hearing loss:
Vascular access
  • LDL apheresis can be performed either with peripheral IV access or with a central venous catheter (CVC)
  • However, chronic treatment and CVC is nearly always required; may begin at ages 6 - 7 years for homozygous familial hypercholesterolemia cases
Indications
  • For therapeutic procedure, the American Society for Apheresis (ASFA) delineates LDL apheresis based on the acuity of the clinical presentation
    • Familial hypercholesterolemia (FH) LDL apheresis homozygotes: Category I
    • Familial hypercholesterolemia LDL apheresis heterozygotes: Category II
    • Liprotein(a) hyperlipoproteinemia LDL apheresis: Category II
    • Peripheral vascular diseases LDL apheresis: Category III
    • Phytanic acid storage disease (Refsum disease) LDL apheresis: Category II
    • Sudden sensorineural hearing loss LDL apheresis: Category III
Volume exchanged and technical details
  • All LDL apheresis systems use heparin alone or in combination with citrate as its anticoagulant so must screen patients for history of heparin induced thrombocytopenia (HIT)
  • The Liposorber instrument only uses heparin; citrate interferes with the interaction between the column and apoB lipoproteins
Adverse events
  • Overall adverse event rate is approximately 11% with no difference between instruments
  • Most are minor: post procedure bleeding, vomiting, hypotention, hypoglycemia
  • Discontinue ACE inhibitor medication prior to adsorption LDL apheresis; it causes excess bradykinin accumulation, leading to hypotensive reactions; can use angiotensin receptor blockers (ARBs) as an alternative
  • Longstanding LDL apheresis can lower vitamin B12, ferritin and transferrin, contributing to anemia and possible need for dietary supplements
Laboratory
Treatment
  • For FH, treatment can be lifelong to stabilize or improve coronary artery atherosclerosis
  • Frequency of procedure is adjusted to maintain target LDL level
  • Multiple LDL procedures are needed to reduce the time averaged LDL levels
  • LDL level can decrease dramatically after single procedure but long term goal is > 60% reduction from baseline