Retrograde Autologous Priming in Surgery of Thoracic Aortic Aneurysm

Objectives: Surgery of thoracic aortic aneurysm (TAA) is associated with blood loss and coagulopathy and is shown to be one of the procedures with the highest red blood cell (RBC) volume needed. The negative impact of blood transfusion has been demonstrated in several studies. Retrograde autologous priming (RAP) has been considered as a safe and easy method to decrease hemodilution during cardiopulmonary bypass (CPB). The aim of this study was to show the effect of RAP during surgery of TAA repair on hemodilution, the need for RBC transfusion, and the postoperative course compared with conventional CPB (cCPB).

Methods: A retrospective study was performed on 120 elective patients with TAA. Half of these patients underwent cCPB and were assigned to the corresponding cCPB group, and the other half received RAP and formed the RAP group. Anesthesia, surgical management, and transfusion criteria were the same for both groups. Statistical analysis was performed using IBM SPSS statistics 23. Chi-square test, Fisher’s exact test, independent t-test and Mann–Whitney’s U-test were used. Statistical significance was assumed at p < 0.05.

Results: In the RAP group, priming fluid was reduced to a mean volume of 661 ± 204 mL compared with 1,611 ± 310 mL in the cCPB group (p < 0.001). Mean intraoperative red cell concentrate (RCC) transfusion 1.97 ± 2.43 (cCPB) versus 0.87 ± 1.33 (RAP) (p = 0.013), postoperative RCC transfusion 1.32 ± 1.82 (cCPB) versus 0.57 ± 1.4 (RAP) (p = 0.002), as well as fresh-frozen plasma (FFP) requirements were significantly lower (p = 0.036) in the RAP group. Higher increase in postoperative lactate levels were measured in the cCPB group. Significantly different drainage loss after 6 hours: 490.63 ± 414.41 mL (cCPB) versus 295.90 ± 342.62 mL (RAP) (p ≤ 0.001), 12 hours: 652.08 ± 463.93 mL (cCPB) versus 450.08 ± 415.51 mL (RAP) (p ˂ 0.001), and 24 hours 866.42 ± 508.38 mL was observed.

Conclusion: RAP is a safe method to reduce RBC transfusion in TAA surgery, without any adverse effects on the clinical outcome. We were able to prove beneficial effects on FFP requirements, postoperative chest drainage volume, and microcirculation perfusion. In consequence and considering the general critical blood shortage, we consider including RAP as a clinical standard during thoracic aortic surgery to reduce costs and risks associated with blood product requirements and hemodilution during CPB.

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