Transfusion medicine
Apheresis
Plateletpheresis

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

Revised: 7 November 2017, last major update March 2014

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

PubMed Search: Plateletpheresis [title] "loattrfree full text"[sb]

Cite this page: Pham, H.P., Booth, G. Plateletpheresis. PathologyOutlines.com website. http://pathologyoutlines.com/topic/transfusionmedplateletpheresis.html. Accessed November 23rd, 2017.
Definition / general
  • Plateletpheresis (or thrombocytapheresis):
    • Process of removing platelets using an automated machine
      • Currently available instrumentations for plateletpheresis procedures are COBE Spectra and Trima Accel from Terumo and Fenwal Amicus from Fresenius Kabi
    • Can be used both as a platelet collection procedure from a donor and as a therapeutic modality to quickly decrease the platelet count in a patient with thrombocytosis
  • Apheresis platelets:
    • Collection by apheresis machine
    • Minimum platelet yield in an apheresis platelet product is 3.0 × 1011 platelets per unit
  • Instrument: Fenwal Amicus (from Fresenius Kabi)
    • Only for donor collection (NOT for therapeutic procedure)
    • Can be single needle or double needle procedure
    • Can collect:
      • Single or double apheresis platelet units
      • One apheresis platelet unit and one plasma unit
      • Single or double apheresis platelet unit and one red blood cell unit
  • Instrument: Trima Accel (from Terumo Medical Corporation)
    • Only for donor collection (NOT for therapeutic procedure)
    • Single needle procedure
    • Can collect:
      • Single or double red blood cell units
      • Single, double or triple apheresis platelet units (depending on donor size, hematocrit and platelet count)
  • Instrument: COBE Spectra (from Terumo Medical Corporation)
    • Can use for both donor collection as well as for patient for therapeutic plateletpheresis
    • Can be single needle or double needle procedure
    • Can collect single or double apheresis platelet units

  • Thrombocytosis:
    • Usually defined as platelet count > 450,000 - 500,000/µL
    • Can be caused by an underlying hematologic malignancy (primary thrombocytosis) or by a reactive process (secondary thrombocytosis)
    • Primary thrombocytosis:
    • Secondary thrombocytosis:
      • More common, accounting for 80 - 90% of cases
      • Platelet function is relatively normal
      • Carries significantly smaller risk of hemorrhage or thrombosis
Epidemiology
  • Incidence for essential thrombocythemia is 1.5 cases per million persons/year
  • Incidence for polycythemia vera is 1.4 cases per million persons/year
Vascular access
  • For patients undergoing plateletpheresis as therapeutic procedures, a central venous catheter might be used
  • For emergent procedure, a femoral apheresis or dialysis catheter should be used because it does not require radiographic confirmation
  • For donors undergoing apheresis platelet or multiple component collection, peripheral access is preferred due the risk of putting in a central venous catheter
  • The minimal allogeneic platelet count is 150,000/µL
Indications
  • For therapeutic procedure, the American Society for Apheresis (ASFA) delineates plateletpheresis based on the acuity of the clinical presentation
    • Symptomatic thrombocytosis: ASFA category II
    • Prophylactic or secondary thrombocystosis: ASFA category III
Volume exchanged and technical details
  • 1.5 to 2 blood volumes is usually performed for therapeutic plateletpheresis procedure
    • This usually reduces the platelet count by 30 - 60%
  • For therapeutic procedures, replacement fluid is usually not indicated because usually less than 15% of the total blood volume is removed
    • Normal saline can be used to maintain blood pressure throughout the procedure
    • For pediatric patients, if the volume removal is > 15% of the total blood volume, 5% albumin replacement can be used for fluid replacement
  • Citrate should be used as the only anticoagulant for the procedure because heparin might cause platelet clumping in the circuit
  • The anticoagulant to whole blood ratio should be between 1:6 and 1:12
Adverse events
  • Plateletpheresis is an apheresis procedure
  • Adverse events include but are not limited to hypotension, citrate related toxicity, bleeding and infection
Treatment
  • For primary thrombocytosis, therapeutic plateletpheresis is not a curative procedure - the reduction of platelets achieved by this procedure is short lived
  • It is only a bridging therapy in addition to other definite treatments, such as chemotherapy
    • For symptomatic treatment:
      • Can be performed daily or as needed to treat thrombosis or hemorrhage in patient with myeloproliferative disorder and thrombocytosis
        • Goal is to decrease platelet count to < 450,000 - 500,000/µL until the effect of chemotherapy takes place
      • Hydroxyurea should be given with plateletpheresis to prevent the rapid reaccumulation of platelets
    • For prophylaxis treatment:
      • Can be used in pregnant or preoperative patients
      • Post procedure platelet count should be individualized based on history of thrombotic or hemorrhagic event at specific platelet count
  • For secondary thrombocytosis, treatment of the underlying cause is indicated