The influence of heparin-coated and uncoated extracorporeal circuits on blood rheology during cardiac surgery.

ABSTRACT

The effect of heparin-coated perfusion circuits on blood trauma during clinical cardiopulmonary bypass (CPB) was studied in order to find out if traumatic changes in the blood could be minimized. Twenty-four patients undergoing coronary artery bypass surgery were randomized prospectively to CPB with heparin-coated circuits (HCC) or non-coated circuits (NCC). The trauma to blood was assessed by measuring damage to blood cells by estimating red and white cell rheology changes. These were measured as red cell filtration rate (RFR) and white cell filtration rate (WFR) using standard microfiltration methods. Furthermore, changes in plasma hemoglobin (P-Hb), whole blood and plasma viscosity were simultaneously assessed. The RFR was significantly reduced in both groups during CPB by 10% in the HCC and 32% in the NCC groups (p less than 0.01). When comparing the HCC and NCC groups, a significant difference was first seen after 30 minutes of bypass (p less than 0.05) and increased at the end of CPB (p less than 0.01). Similar results were seen regarding WFR (15% and 36%, p less than 0.01). After 30 minutes of bypass, a significant difference was seen between HCC and NCC groups (p less than 0.05). Furthermore, a significant increase in P-Hb levels were seen during CPB in both patient groups. At the end of CPB, there was a significant difference in P-Hb levels (HCC 305+/-90 mg/L; NCC 455+/-78 mg/L, p less than 0.01) when comparing the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)