Hematological Assessment of Patients Undergoing Plasmapheresis During Cardiac Surgery

Abstract

Methods of reducing patient exposure to homologous blood transfusions include the technique of intraoperative plasmapheresis for the production of platelet rich plasma (PRP). The present study was designed to determine the patient benefits of PRP by examining hemostatic changes in coagulation screens and viscoelastic whole blood monitoring (Thrombelastography, [TEG]). One hundred fifteen patients undergoing elective cardiac surgery were prospectively randomized into a blinded study. Sixty-three patients had 20 percent of the circulating plasma volume sequestered prior to heparinization and pheresed into PRP, which was reinfused 10 minurtes following heparin reversal with protamine. The control (CTR) group of 52 patients were exposed to no sequestration procedure. Patients were followed to discharge and 112 parameters, including anthropometric, operative, and postoperative factors, were measured. There were no significant differences between patient groups in preoperative, cardiopulmonary bypass (CPB), or surgical parameters. Average PRP volume was 660± 100 ml with a total platelet yield of 1.1 billion platelets per patient. TEG indices were determined at four distinct times during the surgical procedure. The CTR group had significantly higher preCPB TEG indices of2.3±1.2 and 2.1±1.2 (mean±SD), vs. 1.8±1.5 and 1.4±1.7 in the PRP group (p<.04). Following heparin reversal, pre-PRP reinfusion TEG values were similar between groups, although both groups had significantly decreased indices when compared to pre-CPB values. Thirty minutes post-PRP infusion the treatment group had significantly improved TEG recovery when compared to the CTR group, 1.0±1.2 vs. 0.3±1.7 (p<.05). Fibrinolysis increased significantly in both groups post-CPB, but following PRP reinfusion, the treatment group returned to baseline values, while the CTR patients remained significantly elevated. There were no differences between groups in postoperative routine coagulation screens, nor significant changes in postoperative chest tube drainage. Packed red blood cell, fresh frozen plasma, and platelet transfusions in the CTR group were approximately twice as great as the PRP group (p=ns). CTR total homologous blood exposure rate was 3.06±6.6 units compared to 1.41±3.2 units in the PRP group (p<.0007). Discharge hematocrit was 31.5±5.2 percent in the PRP group, and 29.8±4.8 in the CTR group (p<.07). Total length of stay in the hospital was 1 0.8±4.2 days in the PRP patients, compared to 13.4±4.8 days in non-treated patients (p<.03). This study has shown demonstrable hematological benefits of preoperative plasmapheresis during cardiac surgery, with the major reduction of bleeding occurring immediately following the administration of PRP.