To evaluate whether platelet function is preserved after intraoperative autotransfusion using the Same system, a device designed to retain both red blood cells and platelets in patients undergoing on-pump cardiac surgery.

Prospective, single-center, observational study.

University tertiary care hospital, single center.

Forty-four adult patients undergoing elective on-pump cardiac surgery, including valve surgery and coronary artery bypass grafting.

Shed and residual cardiopulmonary bypass blood was collected and processed intraoperatively using the Same system. The resulting reinfusion bag contents were analyzed and compared to intraoperative patient blood samples. Secondary endpoints included blood loss, transfusion requirements, hemoglobin, hematocrit, platelet count up to 48 hours postoperatively, and intensive care unit length of stay.

Platelet function was assessed using flow cytometry and impedance aggregometry. Data from 31 patients were analyzed. The median platelet count was lower in the reinfusion bag than in patient blood (136 v 183 × 10⁹/L; p = 0.0072), with a relative recovery of 76.5% (IQR 57.2-97.0%). The median estimated equivalent compared to platelet concentrates was 0.11 units (0.06-0.19 units), corresponding to approximately 11.4% of one platelet concentrate unit based on a reference value of 3.0 × 10¹¹ platelets per pooled platelet concentrate unit. Considering three processing cycles per patient, this equates to roughly one-third of the platelet count of a standard platelet concentrate unit. Hematocrit was significantly higher in the reinfusion bag (47.3% v 32.6%; p < 0.0001). Platelet activation markers demonstrated partial preservation (e.g., CD62P 40.4%, CD63 52.5%, PAC-1 82.8%). Platelet aggregation responses were partially retained (e.g., ASPI 34.0%). No adverse events have occurred.

The Same device enabled recovery of functional platelets and red blood cells from cardiopulmonary bypass blood. Based on the estimated equivalent yield per processing cycle, the cumulative platelet recovery over three cycles corresponded to approximately one-third of the platelet count of a standard platelet concentrate. This suggests a potentially significant contribution of autologous platelet recovery to perioperative hemostatic support, although the clinical significance of this finding warrants further investigation.