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Comparison of Two Activated Clotting Time Targets During Cardiac Surgery With Cardiopulmonary Bypass: A Prospective
Karin A M Gorter1, Marco C Stehouwer2, Roel de Vroege3
1Department of Perfusion, University Medical Center, Utrecht, the Netherlands.
Insights
A study found that a target activated clotting time (ACT) of ≥400 seconds is equivalent to ≥480 seconds for packed red blood cell (PRBC) transfusions in cardiac surgery. This lower ACT target may reduce blood loss and improve hemoglobin levels post-surgery.
Area of Science:
- Cardiovascular Surgery
- Anesthesiology
- Transfusion Medicine
Background:
- Optimizing anticoagulation during cardiopulmonary bypass (CPB) is crucial for patient outcomes in cardiac surgery.
- Activated clotting time (ACT) monitoring guides heparinization, but target ranges are debated.
- Equivalence of different ACT targets for transfusion needs requires investigation.
Purpose of the Study:
- To determine if a lower target ACT (≥400 seconds) is equivalent to a higher target ACT (≥480 seconds) for packed red blood cell (PRBC) transfusion in cardiac surgery with CPB.
- To evaluate secondary outcomes including blood loss, other blood product transfusions, and postoperative complications.
Main Methods:
- A multicenter, randomized, single-blind, controlled equivalence trial involving 1,021 adult patients undergoing elective cardiac surgery with CPB.
- Patients were randomized to either a lower target ACT (≥400 seconds) or a higher target ACT (≥480 seconds).
- Data on PRBC transfusion, blood loss, hemoglobin levels, and thromboembolic events were collected.
Main Results:
- PRBC transfusion rates were equivalent between the two ACT groups (19.1% vs. 17.2%).
- The lower ACT group showed significantly less postoperative blood loss and higher hemoglobin levels at 6 hours and 1 day, though clinically not relevant.
- Thromboembolic event frequency was similar in both groups.
Conclusions:
- A target ACT of ≥400 seconds is equivalent to ≥480 seconds regarding PRBC transfusion rates in contemporary cardiac surgery.
- The findings suggest that a lower ACT target is comparable for patient outcomes in this setting.
- This supports the potential use of a less intensive anticoagulation target during CPB.
Objectives:
The present study was designed to investigate the equivalence of two target activated clotting time (ACT) values with regard to packed red blood cell (PRBC) transfusion in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). Secondary endpoints include postoperative blood loss, transfusion of other blood products, and postoperative laboratory parameters, including renal function, intensive care unit length of stay, postoperative thrombotic events, and other adverse events.
Design:
Multicenter, randomized, single-blind, controlled equivalence trial. Patients were randomized to a lower target ACT of ≥400 seconds or a higher target ACT of ≥480 seconds.
Setting:
Three tertiary and one university medical center in the Netherlands.
Participants:
1,021 patients ≥18 years of age scheduled for first-time elective cardiac surgery with CPB between November 2019 and December 2023.
Measurements And Main Results:
PRBC transfusion was equivalent in both ACT groups (19.1% v 17.2% risk difference -0.029; 0.066). In the low ACT group, blood loss at 6 and 24 hours postoperative was significantly lower (median [interquartile range], 260 [245] v 300 [250] mL, p = 0.003 and 480 [363] v 550 [410] mL, p = 0.007) and the hemoglobin level at 6 hours and 1 day after surgery significantly higher (mean [95% confidence interval], 11.8 [11.6-11.9] v 11.6 [11.3-11.8] g/dL, p = 0.017 and 11.4 [11.1-11.6] v 11.1 [11.0-11.4] g/dL, p = 0.045) compared with the high ACT group, but lacking clinical relevance. The frequency of thromboembolic events was similar in both groups.
Conclusions:
This study showed that a target ACT of ≥400 seconds is equivalent to a target ACT of ≥480 seconds in terms of intraoperative and postoperative PRBC transfusion rates in the modern cardiac surgery setting. This target range is considered comparable regarding the outcomes of patients undergoing cardiac surgery with CPB.
