Risk of development of neurological complications in prosthetic repair of the aortic ascending portion and arch.

The study comprised a total of 68 patients (presenting) with chronic dissection of the aortic ascending portion and arch, undergoing surgery and subjected to measuring at various stages of the operation the level of cerebral oxygenation (rSO2) of the right and left hemispheres by means of bilateral transcranial spectroscopy. The aim of the study was to examine the risk for the development of neurological complications in patients with chronic dissection of the aortic ascending portion and arch in various methods of cerebral protection during aortic prosthetic reconstruction. Group One consisted of thirty-one 40-to-61-year-old (mean age 51 years) patients who during circulatory arrest (CA) were as cerebral protection subjected to antegrade cerebral perfusion (ACP) on the background of moderate hypothermia (23-24°C). Group Two included thirty-seven 40-to-58-year-old (mean age 48 years) patients who during CA were subjected to cerebral protection consisting in craniocerebral hypothermia on the background of total deep hypothermia (18°C). Prior to surgery and in the immediate period thereafter, all patients underwent clinical and instrumental examination of the neurological status. During CA while aortic arch repair in Group One patients at the expense of maintaining cerebral perfusion a decrease in rSO2 registered in the right and left hemispheres amounted to only 11.8 and 8.7%, respectively, compared with the baseline values. In Group Two patients during CA a decrease in rSO2 along the right and left hemispheres amounted to 29.6 and 30.9% compared with the initial values, which was statistically significantly more than in Group One (p=0.002 and p=0.003). Thus, in Group Two patients during CA cerebral hypoperfusion resulted in a considerable decrease in oxygen supply of the brain, in spite of systemic deep hypothermia and craniocerebral hypothermia, promoting reduction of cerebral metabolism. Using ACP during CA in Group One patients maintained the oxygen status of the brain at an optimal level. In Group One patients, in the early postoperative period neurological complications were registered in 12.9% of cases. In Group Two, neurological complications were noted in 35.1% of cases. The univariate logistic regression analysis demonstrated that the risk for the development of any neurological complications depended on the degree of a decrease in rSO2 during CA while prosthetic repair of the aortic arch relative to the previous values - OR 1.25; 95% CI 1.11-1.65; p=0.02. Hence, deep hypothermia and craniocerebral hypothermia used as cerebral protection during CA turned out to be less effective compared with ACP, because despite reduction of metabolic requirements of the brain, cerebral hypoperfusion substantially of neurological status impairments in the early postoperative period.