Reduktion neuropsychologischer Dysfunktionen nach Herzoperation durch Heparinbeschichtung des extrakorporalen Zirkulationssystems

Cerebral embolic events have been postulated as a causative factor for neuropsychological dysfunction and cognitive decline after cardiopulmonary bypass procedures (CPB). In a prospective study we evaluated whether brain injury resulting from microemboli during CPB could be reduced by heparin-coated surfaces of the bypass circuits (BC). From May until October 1996 in 72 patients (coronary artery bypass procedures), identical cardiopulmonary system configurations were used (Quadrox membrane oxygenator, Fa. Jostra), 36 systems were heparin-coated (group I) and 36 systems remained uncoated (group II). Neuropsychological tests, which required visual scanning, attention, and concentration (d2-test, Brickenkamp), were performed in each patient preoperatively and 6 and 9 days following the operation. Blood samples for analysis of S-100 protein (marker of cerebral injury) were collected preoperatively, 1 and 5 hours after CBP. In 38 patients (19 from each group) arterial filters of BC were analyzed by scanning electron microscopy (SEM) to determine platelet and leucocyte deposition and fibrin deposits. D2-tests revealed a stronger depression in group II postoperatively with a high significance (median depression 14% versus 4% in group I, p=0.05). Both groups returned to normal within 9 days. S-100 levels 1 and 5 hours postoperatively were higher in group II (median 0.91 versus 0.75, median 0.20 versus 0.10 respectively). The difference did not reach statistical significance. Statistically significant differences in the surface coverage units of the arterial filters were observed between the two groups (p<0.01). In standard circuits the number of cell or fibrin deposits increased according to the duration of extracorporeal circulation but not in heparin-coated circuits. Our study suggests that cerebral injury following CPB may be reduced by a heparin coating of the bypass circuits. We recommend heparin-coated bypass circuits in cardiac procedures with a long duration of extracorporeal circulation. Reduction of cell and fibrin deposits in the extracorporeal bypass circuits may be heightened in this patient population.