Cerebral regional oxygenation during aortic coarctation repair in pediatric population.

OBJECTIVE During repair of aortic coarctation, clamping of the transverse aortic arch proximal to the left common carotid artery occludes blood flow to the left carotid and vertebral arteries. The objective of the present study is to determine whether blood flow through the right carotid and vertebral arteries provides adequate cerebral blood flow during aortic cross-clamping, as assessed by near-infrared spectroscopy. METHODS In 11 consecutive children undergoing aortic coarctation repair through a standard posterolateral thoracotomy, regional cerebral oxygen saturation (cSO(2)) was measured using near-infrared spectroscopy. Six patients underwent an extended end-to-end repair, in which the aortic cross-clamp was placed in between the innominate and left common carotid arteries (extended repair group). Five patients underwent a standard end-to-end repair in which the cross-clamp was clamp placed between the left common carotid and subclavian arteries (standard repair group). RESULTS After aortic clamping, there was a significant decrease in cSO(2) in the extended repair group, whereas the cSO(2) increased in the standard repair group (-9.2+/-12.2 vs 6.0+/-5.1%, extended vs standard repair groups, p=0.03). In the extended repair group, the cSO(2) decreased linearly during the aortic cross-clamping period (r(S)=-0.842, p<0.001), while in the standard repair group, the cSO(2) increased during the same time period (r(S)=0.786, p<0.001). Regression analysis identified the site of aortic cross-clamping as the sole independently significant variable explaining changes in the cSO(2) during aortic cross-clamping (p<0.03), whereas neither age nor duration of aortic cross-clamping was statistically significant. There were no postoperative neurological impairments in either group of patients. CONCLUSION During aortic coarctation repair, aortic cross-clamping proximal, as compared to distal, to the left carotid artery is associated with significantly decreased regional cerebral oxygen saturation, as measured by near-infrared spectroscopy. Although no short-term clinical impairments were identified, long-term follow-up in a larger cohort is needed to study the effects of unbalanced cerebral oxygenation during clamping of the transverse arch. These data suggest that cerebral saturation monitoring is warranted, and may be indicative of cerebral hypoperfusion.