Hypertension as a risk factor for cerebral injury during cardiopulmonary bypass - Protein S100B and transcranial Doppler findings

We studied 22 patients aged 53-78 years scheduled for cardiac surgery under cardiopulmonary bypass. Blood pressure, cardiac output, transcranial Doppl er blood flow velocity, arterial blood gases, body temperature and protein S100B, as a marker for cerebral integrity, were evaluated in normotensive a nd hypertensive patients. Pre-operative mean (SD) arterial blood pressure w as 93 (11) mmHg in the normotensive group compared with 116 (15) mmHg in th e hypertensive group. We found an increase in protein S100B levels in both groups. Serum protein S100B concentrations in the hypertensive group were s ignificantly higher than in the normotensive group (p < 0.001). The highest mean (SD) values were 2.04 (0.65) <mu>mol.l(-1) in the normotensive group and 7.02 (4.55) mu mol.l(-1) in the hypertensive group. These results sugge st that cardiopulmonary bypass is associated with a significantly higher ra te of cerebral injury in hypertensive patients than in normotensive patient s. This may be due to altered autoregulation and insufficient cerebral perf usion. Modifications of cardiopulmonary bypass management for hypertensive patients might be made to decrease the risk of cerebral injury.