The safety of moderate hypothermic lower body circulatory arrest with selective cerebral perfusion:: A propensity score analysis

Objective: There is no common guideline on what temperature should be achieved at the lower body circulatory arrest followed by the initiation of selective cerebral perfusion. Methods: Between October 1999 and August 2005, a total of 377 patients underwent repair of the aortic arch with selective cerebral perfusion and hypothermic circulatory arrest at 20 degrees C to 28 degrees C and were divided into two groups: (1) 125 patients with deep lower body circulatory arrest at 20 degrees C to 24.9 degrees C (deep lower body circulatory arrest group) and (2) 252 patients with moderate lower body circulatory arrest at 25 degrees C to 28 degrees C (moderate lower body circulatory arrest group). To compensate for the differences in patient characteristics, we used a propensity score matching analysis, and comparable patients, 92 patients from each group, were identified for final analysis. Results: There were no significant differences in mortality or morbidity between deep and moderate lower body circulatory arrest, in either the entire study cohort or the propensity-matched cohort. C-reactive protein level 1 day after the operation approached but fell short of significance (108.4 +/- 47.7 mg/L in deep lower body circulatory arrest group and 95.8 +/- 44.2 mg/L in moderate lower body circulatory arrest group, P = .07). The mean temperatures at the initiation of lower body circulatory arrest were 24.1 degrees C +/- 2.2 degrees C in patients who underwent reexploration for bleeding and 24.9 degrees C +/- 1.8 degrees C in patients who did not (P = .025); the difference also reached statistical significance in multivariate analysis (P = .046, odds ratio 0.796). Conclusions: Our results suggest that moderate lower body circulatory arrest can be safely performed for aortic arch repair. In fact, postoperative inflammatory response tended to be lower in patients with moderate lower body circulatory arrest than those with deep lower body circulatory arrest, and deep lower body circulatory arrest was a strong risk factor for reexploration for bleeding.