No benefit of reduced heparinization in thoracic aortic operation with heparin-coated bypass circuits

Heparin coating of the cardiopulmonary bypass circuit attenuates inflammatory response and confer clinical benefits in cardiac operations. The positive effects may be amplified with reduced systemic heparin dosage. We studied markers of inflammation and coagulation in thoracic aortic operations with heparin-coated circuits and standard vs reduced systemic heparinization.

Thirty patients were randomized to standard (group S; 300 IU/kg initially; activated clotting times [ACT] > 480 seconds; 5,000 IU in prime; n = 16) or reduced (group R; 100 IU/kg initially; ACT > 250 seconds; 2,500 IU in prime; n = 14) dose systemic heparin. The following markers were analyzed perioperatively: (a) inflammatory response; acute phase cytokine interleukin-6, and granulocytic proteins myeloperoxidase and lactoferrin; (b) complement activation; factor C3a and the C5a-9 terminal complement complex [TCC]; and (c) coagulation; thrombin-antithrombin III complex.

The clinical outcome did not differ between groups. Four (29%) patients in group R had a perioperative thromboembolic event. All studied markers were significantly elevated during and throughout cardiopulmonary bypass in both groups. Maximal values were higher in group R for all variables except for TCC. There were no statistically significant intergroup differences regarding markers of inflammation, complement activation, or coagulation activation.

The blood trauma in thoracic aortic operation is extensive, as reflected by the elevation of the studied biochemical markers, even when heparin-coated cardiopulmonary bypass circuits are used. In this study, we did not detect any benefits, either biochemical or clinical, of reducing the dose of systemic heparin.