Surgical results of low-dose systemic heparinization (1 mg/kg, 100 IU/kg) in thoracic aortic operation combined with a heparin-coated cardiopulmonary bypass circuit: Is low-dose heparinization safe during deep hypothermic circulatory arrest?

Heparin-coated cardiopulmonary bypass circuits allow a reduction in the use of systemic heparin administered during cardiopulmonary bypass. This study was carried out to investigate safety during deep hypothermic circulatory arrest in this low-dose heparin group during thoracic aortic operation. Heparin-coated cardiopulmonary bypass circuits were used in 30 adult patients who underwent thoracic aortic operations that required deep hypothermic circulatory arrest. The patients were divided into two groups. Six patients received 300 IU/kg of heparin, and the remaining 24 patients received 100 IU/kg. Clinical outcomes (mortality, incidence of stroke, and transfusion volumes during operation) were examined. All devices remained functional throughout the procedures, and no systemic emboli were detected. Two deaths occurred in the high-dose heparin group, but no deaths occurred in the low-dose heparin group (P = 0.03). The percentage of patients requiring transfusion was similar in the two groups (66.7% vs. 70.8%), but the median exposure to allogenic blood products was greater in the high-dose heparin group than in the low-dose heparin group (9.8 ± 9.5 units vs. 5.5 ± 5.2 units; P = 0.09). Reduced systemic heparinization, combined with hepar-in-coated cardiopulmonary bypass circuits during deep hypothermic circulatory arrest, can be performed with acceptably low early mortality in thoracic aortic operations. Patients are not at increased risk for stroke.