Continuous hypothermic low-flow-perfusion during aortic arch operations is neuroprotective and cardioprotective

Background: Aortic arch operations in pediatric patients using low-flow-perfusion-techniques have been standardized to a certain degree, but some additional beneficial effects are still unknown.

Methods: Twenty-six male newborn piglets (10–15kg) underwent aortic arch surgery under general anaesthesia using either low-flow-perfusion via the innominate artery (group 1: 25°C, n=12) or conventional deep-hypothermic-circulatory-arrest (group 2: 20°C, n=14). Cortical SSEP and carotid blood flows where measured during the experiment. All animals had detailed evaluation of their hemodynamic performance throughout the experiment. Histological brain examination was performed at the end of the experiment.

Results: Right-carotid-artery-flow was doubled (group 1) during low-flow-perfusion via the innominate artery in all piglets. Cortical SSEP returned to preoperative values in all but two low-flow-animals. There was no return of SSEP in all piglets operated under deep-hypothermic-circulatory-arrest/DHCA (p<0.01). Histological examination of five defined brain regions showed no significant differences in brain cell damage. Cardiac-output (+27.2%) and cardiac-index (+13.9%) increased significantly in all low-flow animals compared to preoperative hemodynamic values. Animals in group 2 (DHCA) had a slightly lower hemodynamic performance compared to their preoperative status (–5.3% for CO and –8.8% for CI). There was no difference in inotropic support between both groups.

Conclusion: Low-flow-perfusion via the innominate artery provides superior neuroprotection compared to DHCA with gradually less histological brain damage. There was a significantly improved recovery of SSEP resulting in a significant better neurologic outcome. Further, hemodynamic performance regarding cardiac-output and cardiac-index is significantly improved after aortic arch surgery when continuous brain perfusion has been used.