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Effect of anticoagulation protocol on outcome in patients undergoing CABG with heparin-bonded cardiopulmonary bypass
G S Aldea1, P O'Gara, O M Shapira
1Department of Cardiothoracic Surgery, Boston University Medical Center, Massachusetts 02118-2393, USA.
Insights
A lower anticoagulation protocol with heparin-bonded cardiopulmonary bypass circuits (HBCs) reduces homologous transfusions in coronary artery bypass grafting patients. This approach is safe, with no increased risk of clinical or thromboembolic complications.
Area of Science:
- Cardiovascular Surgery
- Anesthesiology
- Hematology
Background:
- Heparin-bonded cardiopulmonary bypass circuits (HBCs) combined with lower anticoagulation protocols reduce transfusions and improve outcomes in coronary artery bypass grafting (CABG).
- The specific contribution of lower anticoagulation protocols to outcomes with HBCs remains unclear.
- The thrombogenic risk associated with lower anticoagulation protocols and HBCs is debated.
Purpose of the Study:
- To determine if a lower anticoagulation protocol influences clinical outcomes in patients undergoing primary CABG using HBCs.
- To assess the thrombogenic risk associated with lower anticoagulation protocols when used with HBCs.
Main Methods:
- A prospective randomized study involving 244 patients undergoing primary CABG.
- Patients were treated with HBCs and randomized to either a full (ACT > 450s) or lower (ACT > 250s) anticoagulation protocol.
- Thrombin generation markers (thrombin-antithrombin complexes, prothrombin fragment 1.2) were measured in a subset of 58 patients.
Main Results:
- The lower anticoagulation protocol group required fewer blood products (24.2% vs. 35.8%) and homologous donor units (0.50 vs. 1.08).
- Clinical outcomes were similar, with a modest reduction in hospital stay for the lower anticoagulation group (5.26 vs. 5.63 days).
- No significant differences in microemboli, thromboembolic complications, or neurologic/neuropsychologic outcomes were observed between groups.
Conclusions:
- HBCs with a lower anticoagulation protocol effectively reduce homologous transfusions in CABG patients.
- This combined approach does not increase the risk of clinical, hematologic, or microscopic thromboembolic complications.
- The findings support the safe and effective use of lower anticoagulation protocols with HBCs for blood conservation in CABG surgery.
Background:
We have demonstrated that the use of heparin-bonded cardiopulmonary bypass circuits (HBCs) combined with a lower anticoagulation protocol as an adjunct to an integrated blood conservation strategy decreases the incidence and magnitude of homologous transfusion and improves clinical outcome in patients undergoing primary coronary artery bypass grafting. It is not known whether it is the lower anticoagulation protocol that influences outcome in patients treated with HBCs. Furthermore, the thrombogenic risk of using lower anticoagulation with HBCs still is debated.
Methods:
To answer these questions, a prospective randomized study was conducted in which 244 patients undergoing primary coronary artery bypass grafting were treated with HBCs and randomized to undergo either a full (activated clotting time, > 450 seconds) or a lower (activated clotting time, > 250 seconds) anticoagulation protocol. In addition to clinical outcome, levels of thrombin generation markers during and after cardiopulmonary bypass were assessed in a consecutive subset of 58 patients (full anticoagulation profile = 28, lower anticoagulation profile = 30) by measuring thrombin-antithrombin complexes and prothrombin fragment 1.2. Levels of these markers also were correlated with the activated clotting time during cardiopulmonary bypass.
Results:
Preoperative and intraoperative risk profiles and other characteristics were similar in both groups, with more than 60% of patients undergoing nonelective operation. Compared with the full anticoagulation protocol group, patients in the lower anticoagulation protocol group were less likely to require blood products (24.2% versus 35.8%, respectively; p = 0.047) and received substantially fewer homologous donor units (0.50 +/- 0.92 versus 1.08 +/- 2.10 U, respectively; p = 0.005). Clinical outcomes were uniformly outstanding (but similar) in both treatment groups, with a modest reduction in the length of the hospital stay in the lower anticoagulation protocol group (5.26 +/- 1.23 versus 5.63 +/- 1.73 days, respectively; p = 0.05). The use of HBCs with a lower anticoagulation protocol was not associated with any adverse clinical events. Thrombin generation increased during cardiopulmonary bypass in both treatment groups, but was unrelated to the anticoagulation protocol or the activated clotting time (r2 = 0.03). No differences between the full and lower anticoagulation protocol groups were noted in the number of microemboli detected by transcranial Doppler analyses during cardiopulmonary bypass (n = 40) or in the postoperative neurologic and neuropsychologic outcomes (n = 30).
Conclusions:
This study definitively demonstrates that, when used appropriately, patients who are treated with HBCs and a lower anticoagulation protocol have a lower incidence and magnitude of homologous transfusion and are not at any added risk for clinical, hematologic (thrombin-antithrombin complex and fragment 1.2 measurements), or microscopic (transcranial Doppler analyses) thromboembolic complications or for neurologic or neuropsychologic deficits.