Systemic steroid pretreatment improves cerebral protection after circulatory arrest

Background. This study evaluates whether systemic steroid pretreatment enhances neuroprotection during deep hypothermic circulatory arrest (DHCA) compared with steroid in cardiopulmonary bypass (CPB) prime. Methods. Four-week-old piglets randomly placed into two groups (n = 5 per group) were given methylprednisolone (30 mg/kg) into the pump prime (group PP), or pretreated intravenously 4 hours before CPB (group PT). All animals underwent 100 minutes of DHCA (15 degreesC), were weaned off CPB, and were sacrificed 6 hours later. Postoperative changes in body weight, bioimpedance, and colloid oncotic pressure (COP) were measured. Cerebral trypan blue content, immunohistochemical evaluation of transforming growth factor-beta (1) (TGF-beta (1)) expression, and caspase-3 activity were performed. Results. Percentage weight gain (group PP 25.0% +/- 10.4% versus group PT 12.5% +/- 4.0%; p = 0.036), and percentage decrease in bioimpedance (PP 37.2% +/- 14.5% versus PT 15.6% +/- 7.9%; p = 0.019) were significantly lower, whereas postoperative COP was significantly higher in group PT versus group PP (PT 15.3 +/- 1.8 min Hg versus PP 11.6 +/- 0.8 mm Hg; p = 0.003). Cerebral trypan blue (ng/g dry tissue) was significantly lower in group PT (PT 5.6 X 10(-3) +/- 1.1 X 10(-3) versus PP 9.1 X 10(-3) +/- 5.7 X 10(-4); p = 0.001). Increased TGF-beta (1) expression and decreased caspase-3 activity were shown in group PT. Conclusions. Systemic steroid pretreatment significantly reduced total body edema and cerebral vascular leak and was associated with better immunohistochemical indices of neuroprotection after DHCA. (C) 2001 by The Society of Thoracic Surgeons.