Hypercoagulability in pediatric autologous hematopoietic progenitor cell collection – Is it the time to reconsider screening? – A case report

Abstract

Peripheral blood hematopoietic progenitor cell harvest by apheresis in pediatric patients, a double-edged sword, has advantages and disadvantages over conventional bone marrow transplantation. The effect of granulocyte colony-stimulating factor (G-CSF) mobilization on hemostasis in literature is very scarce. A 3-year-old female child with metastatic neuroblastoma planned for autologous transplant. Following G-CSF mobilization (75 mg; 4 days), the procedure was performed with all default parameters in Spectra Optia with an acid citrate dextrose (ACD) flow rate 1:12, assuming 3-total blood volume (TBV) to be processed with 150 ml of expected collection with target yield of 6 × 106 CD34 cells/kg. Despite normal coagulation laboratory parameters, it was abandoned for reasons such as low-flow alarms and thrombi in the kit tubings. In the subsequent procedures, the ACD to whole blood ratio was decreased to 1:16, and used bolus of heparin was followed by continuous heparin infusion throughout the procedure. Despite using heparin anticoagulation, a long thrombus was aspirated at needleless port. The procedure was completed with continuous low-flow alarms. A cumulative dose of 5.67 × 106 CD34 cells/kg was achieved over four procedures, but the cause of hypercoagulability was unknown. All the coagulation parameters were within normal limits before and after the procedure. The exact cause for hypercoagulability remains elusive. There are no studies or case reports in the pediatric population on hypercoagulability following apheresis procedure after G-CSF mobilization, but evidence is available for adults, with lack of explanation. It can also be due to low draw flow from the patient side or embolization of thrombi developed in the anticoagulant unprimed site in the kit tubings. More extensive studies are required to explain the mechanism of hypercoagulability during apheresis procedures in the pediatric population.

Keywords

• autologous
• granulocyte colony-stimulating factor
• hematopoietic progenitor cells
• pediatric
• stem cells
• thrombosis
• transplant