Blood management in heart surgery: Avoiding inappropriate transfusion

SAN DIEGO – Limiting hemodilution, using antifibrinolytics, and transfusing based on the patient’s current condition rather than hemoglobin level are important steps toward appropriate blood management during cardiac surgery, according to a presentation at the 38th Annual Cardiothoracic Surgery Symposium.

C. David Mazer, MD, of St. Michael’s Hospital, University of Toronto, discussed strategies to reduce transfusion in cardiac surgery and reviewed the recent European guidelines for blood management in cardiac surgery.

“Cardiologists tell me that you live with plaque, but it’s the thrombus that kills you,” Mazer said. “And I say ‘Yes, but bleeding’s no fun either.’ So, our goal is to try to keep the patient’s own red cells as much as possible.”

Mazer cited the “three pillars of blood management:” optimizing hematopoiesis, minimizing blood loss, and harnessing and optimizing the physiologic tolerance of anemia. He discussed a single-center Italian study by Ranucci et al, which outlined the “deadly triad” of cardiac surgery: major bleeding, transfusions and anemia.

“You can see the relationship to increasing risk with even just bleeding and no transfusion, or no major bleeding and transfusion,” he said. “The combination of the two with preoperative anemia confers the highest risk.”

The management of preoperative anemia should be based on whether the patient has iron deficiency, Mazer said. In these cases, iron supplementation can be provided orally or intravenously.

“If they have other causes of anemia, sometimes those are iron-responsive, sometimes they’re not,” Mazer said. “The basic bottom line is if they have other causes of anemia that are easily identifiable, like a vitamin deficiency, then address those. If not, refer to a hematologist.”

He added that the European guidelines advise against preoperatively transfusing patients with anemia. Instead, they recommend giving oral or IV iron and possibly supplementing with erythropoietin.

In terms of major bleeding, Mazer advocated using antifibrinolytic therapy, which is included as a Class I recommendation in the European Society guidelines.

He said Class III recommendations do not indicate the prophylactic use of FFP, fibrinogen DDAVP or recombinant factor VIIA.

Regarding intraoperative anticoagulation, Mazer addressed Class I and Class II recommendations around antithrombin treatment.

“In Level I, it’s indicated for patients who are heparin-resistant and antithrombin-deficient; level III it should not be given to reduce bleeding,” he said. “Level II suggests heparin-level guided management for both dosing and reversal, and in patients with HIT, anticoagulation with bivalirudin.”

Mazer also addressed volume administration guidelines, including a Level I or Class I recommendation to limit hemodilution and Level III evidence against the use of directed hemodynamic therapy.

“Low molecular-weight starches in priming or non-priming solutions is not recommended,” he said. “However, I will say there are some studies in cardiology that did not show an adverse effect with the starches. Then autologous preoperative or intraoperative normovolemic hemodilution can be considered.”

During extracorporeal life support, the guidelines suggest that clinicians consider bivalirudin and argatroban as alternatives for prolonged ECMO therapy to prevent heparin-induced thrombocytopenia, Mazer said.

He concluded by advising against prophylactic transfusion cardiac surgery patients.

“There’s ongoing risks with anemia in allogenic transfusion; the patient’s own red cells are best,” he said. “Tranexamic acid is very effective in reducing transfusion, but there are ongoing controversies related to it. Perioperative management is evolving.” – by Jennifer Byrne

References:

Mazer DC. Update on Blood Conservation. Presented at: The Annual Cardiothoracic Surgery Symposium; Sept. 6-9, 2018; San Diego.

Ranucci, et al. Ann Thorac. Surg. 2013; doi: 10.1016/j.athoracsur.2013.03.015.

Disclosure: Mazer reports no relevant disclosures.