Is there an increased risk of blood transfusion in pediatric patients with cyanotic congenital heart disease (CHD) undergoing corrective surgery?

From the Guidelines

Yes, there is an increased risk associated with blood transfusion in pediatric patients with cyanotic congenital heart disease undergoing corrective surgery. These patients typically have higher baseline hematocrit levels (polycythemia) as a compensatory mechanism for chronic hypoxemia. When these patients receive blood transfusions during surgery, they face several specific risks. First, the increased blood viscosity from their already elevated red cell mass can worsen when combined with transfused blood, potentially leading to microvascular thrombosis and impaired tissue perfusion. Second, these patients often have coagulation abnormalities including platelet dysfunction and consumption of clotting factors, which can be exacerbated during massive transfusions. Third, the cardiopulmonary bypass circuit used during surgery causes hemodilution, which can rapidly change their hematocrit levels and require careful management. Additionally, these patients are particularly sensitive to volume status changes, and transfusions must be carefully titrated to avoid volume overload that could worsen right-to-left shunting. To manage these risks, surgical teams typically use modified transfusion triggers, careful monitoring of coagulation parameters, and judicious use of blood products with consideration of washed red cells in some cases to reduce inflammatory mediators. Point-of-care testing for coagulation and hemoglobin levels is often employed for real-time management during these complex procedures.

Some key considerations for managing blood transfusions in these patients include:

• Careful monitoring of coagulation parameters and hematocrit levels
• Use of modified transfusion triggers to avoid excessive blood transfusions
• Judicious use of blood products, including consideration of washed red cells to reduce inflammatory mediators
• Careful titration of transfusions to avoid volume overload and worsening of right-to-left shunting
• Use of antifibrinolytics, such as tranexamic acid (TXA), to reduce bleeding and transfusion requirements, as suggested by recent studies 1.

It is essential to note that the use of antifibrinolytics, such as TXA, has been shown to be effective in reducing bleeding and transfusion requirements in pediatric patients undergoing cardiac surgery, including those with cyanotic congenital heart disease 1. However, the decision to use these agents should be made on a case-by-case basis, taking into account the individual patient's risk factors and medical history.

In terms of specific patient populations, a recent study found that TXA was associated with improved outcomes, including lower mortality and bleeding, in pediatric patients undergoing cardiac surgery, including those with cyanotic congenital heart disease 1. Another study found that TXA was effective in reducing bleeding and transfusion requirements in neonates undergoing cardiac surgery, including those with cyanotic congenital heart disease 1.

Overall, the management of blood transfusions in pediatric patients with cyanotic congenital heart disease undergoing corrective surgery requires careful consideration of the patient's individual risk factors and medical history, as well as the use of evidence-based strategies to minimize the risks associated with blood transfusions.

From the Research

Increased Risk of Blood Transfusion in Cyanotic Congenital Heart Disease

• Cyanotic congenital heart disease is associated with an increased risk of bleeding in children undergoing cardiac surgery 2.
• The presence of cyanotic heart disease is an independent predicting factor for fresh frozen plasma (FFP) and platelet transfusion in these patients 2.
• Cyanotic children exhibit higher perioperative blood losses, both intraoperative and postoperative, compared to acyanotic children 2.

Coagulation Profile and Blood Transfusion

• Thromboelastometry assays reveal more complex coagulation disturbances in cyanotic than acyanotic children 2.
• Preoperative coagulation pattern is associated with postoperative blood products transfusion in children with congenital heart disease, with cyanotic patients requiring more frequent postoperative transfusions of fibrinogen and fresh frozen plasma 3.
• Patients with lower presurgery prothrombin activity and platelet count require more fibrinogen transfusion, and those with longer clot formation time and reduced maximum clot firmness require more transfusions 3.

Strategies to Reduce Blood Loss and Transfusion Requirements

• The use of antifibrinolytic agents such as tranexamic acid and aprotinin can reduce postoperative blood loss and transfusion requirements in cyanotic children undergoing cardiac surgery 4, 5.
• The combination of aprotinin and tranexamic acid does not seem to be more effective than either agent alone in reducing blood loss and transfusion requirements 4.
• Epsilon aminocaproic acid and tranexamic acid are equally effective in reducing postoperative blood loss and blood product requirements in children with cyanotic heart disease undergoing corrective surgery 5.

Pathophysiology of Cyanotic Congenital Heart Disease

• Long-standing hypoxemia in children with cyanotic congenital heart disease leads to complex alterations in whole blood composition and coagulation profile, including secondary erythrocytosis and deficiencies in coagulation proteins 6.
• These alterations increase the risk of thrombosis and postoperative hemorrhage, and anesthesiologists need to understand the pathophysiology and available strategies to lessen these risks 6.