Engraftment in Sibling Allogeneic Stem Cell Transplant Recipients Following the Change in Bone Marrow Collection Devices

Topic Significance & Study Purpose/Background/Rationale: The length of time between stem cell infusion and engraftment can significantly impact the recipient’s survival and quality of life. We observed that the days until engraftment in stem cell transplant recipients has increased for unknown reasons.  One possible explanation considered was a change in bone marrow collection devices. October 2009 the Baxter Fenwal P/N collection System was discontinued.  We switched to a new device called the BioAccess Marrow Collection System. This project investigated whether the change in collection systems has impacted our patients’ time to engraftment after stem cell infusion.

Methods, Intervention, & Analysis:: The number of days to engraftment after stem cell transplant was evaluated by a chart review of 67 patients that were transplanted at this hospital between 2001 and 2014. The average days to engraftment after collection using the Baxter Fenwal P/N Collection System (before 10/2009) versus the BioAccess Collection System (after 10/2009) were compared. All evaluated patients had received matched sibling donors transplants with a conditioning regimen of Fractionated TBI (1320 cGy) with either Etoposide (60 mg/kg) or Busulfan (16 mg/kg) and Cyclophosphamide (120 mg/kg). All subjects also received GVHD prophylaxis with Cyclosporine and  Methotrexate (15 mg/m2 on day +1 and 10 mg/m2 on days +3, +6, +11).

Findings & Interpretation: Analysis of the data showed that the mean days to engraftment for patients given cells collected with the Baxter Fenwal P/N Collection System was 25.22 days with a standard deviation of 2.9. Patients given cells collected with the BioAccess Collection System had a mean engraftment time of 26.78 days with a standard deviation of 1.84. Further analysis with an unpaired T test revealed that these results were statistically significant, with p=0.01.

Discussion & Implications: This was a QA project to explore possible causes for increased time to engraftment for our SCT patients. The findings were found to be statistically significant. However, they didn’t show the clinical significance expected, as the means before and after the change in collection devices only differed by one day. We therefore do not see a need for changing our current bone marrow collection system