Hori Daijiro, Ono Masahiro, Adachi Hideo, Hogue Charles W
Division of Cardiac Surgery, Department of Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Department of Cardiovascular Surgery, Saitama Medical Center, Jichi Medical University, Saitama, Japan.
Eur J Cardiothorac Surg. 2016 Jan;49(1):281-7. doi: 10.1093/ejcts/ezv018. Epub 2015 Feb 1.
Combined carotid artery endarterectomy (CEA) and coronary artery bypass grafting surgery is considered to reduce long-term stroke risk for patients with severe carotid artery stenosis. The benefits of CEA for improving cerebral perfusion during subsequent cardiopulmonary bypass (CPB) are unclear. The purpose of this pilot study was to assess cerebral autoregulation and cerebral oximetry in patients undergoing combined CEA and cardiac surgery with those undergoing cardiac surgery without significant carotid artery stenosis or with uncorrected stenosis.
Cerebral autoregulation was monitored continuously in 257 patients with the cerebral oximetry index (COx). COx represents a moving Pearson's correlation coefficient between low-frequency changes in regional cerebral oxygen saturation (rScO2) and mean arterial pressure that has been validated in previous investigations. Impaired autoregulation was defined as a value of COx ≥0.3.
Nineteen patients had prior CEA, 8 underwent combined CEA and cardiac surgery, 8 had uncorrected stenosis >70% and 197 had stenosis <50%. Combined, patients with stenosis >70% had a higher COx before CPB compared with those with stenosis <50% (median, 0.26, 25th percentile and 75th percentile [p25-p75], 0.18-0.33 vs 0.18, p25-p75, 0.07-0.27, respectively, P = 0.054). Patients who underwent combined CEA and cardiac surgery had a higher COx before surgery compared with those with prior CEA (P = 0.027) and stenosis <50% (P = 0.026). There were no differences in average COx or rScO2 during CPB in patients undergoing combined CEA and cardiac surgery compared with those with prior CEA (P = 0.53, 0.27) and those with stenosis <50% (P = 0.71, 0.19), respectively. During CPB, patients with uncorrected stenosis had an average COx of 0.36 (p25-p75, 0.28-0.56) indicating cerebral autoregulation impairment, and lower rScO2 compared with patients with prior CEA (P = 0.006) and stenosis <50% (P = 0.005).
While higher at baseline, patients undergoing CEA immediately before cardiac surgery had COx and rScO2 measurements during CPB similar to those with non-significant stenosis in contrast to those patients with uncorrected stenosis who had evidence of impaired autoregulation and lower rScO2. These preliminary results suggest the potential utility of COx, possibly for complimenting patient selection for CEA as well as for individual patient management during surgery.
颈动脉内膜切除术（CEA）联合冠状动脉旁路移植术被认为可降低重度颈动脉狭窄患者的长期卒中风险。CEA对改善后续体外循环（CPB）期间脑灌注的益处尚不清楚。本前瞻性研究的目的是评估接受CEA联合心脏手术的患者与接受无明显颈动脉狭窄或未矫正狭窄的心脏手术患者的脑自动调节和脑血氧饱和度。
连续监测257例患者的脑血氧饱和度指数（COx）以评估脑自动调节。COx代表局部脑血氧饱和度（rScO2）低频变化与平均动脉压之间的移动Pearson相关系数，此前研究已证实其有效性。自动调节受损定义为COx≥0.3。
19例患者曾接受CEA，8例接受CEA联合心脏手术，8例未矫正狭窄>70%，197例狭窄<50%。合并分析显示，狭窄>70%的患者在CPB前的COx高于狭窄<50%的患者（中位数分别为0.26，第25百分位数和第75百分位数[p25 - p75]为0.18 - 0.33，对比0.18，p25 - p75为0.07 - 0.27，P = 0.054）。接受CEA联合心脏手术的患者术前COx高于曾接受CEA的患者（P = 0.027）和狭窄<50%的患者（P = 0.026）。与曾接受CEA的患者（P = 0.53，0.27）和狭窄<50%的患者（P = 0.71，0.19）相比，接受CEA联合心脏手术的患者在CPB期间的平均COx或rScO2无差异。在CPB期间，未矫正狭窄的患者平均COx为0.36（p25 - p75为0.28 - 0.56），表明脑自动调节受损，且与曾接受CEA的患者（P = 0.006）和狭窄<50%的患者（P = 0.005）相比，rScO2较低。
虽然术前基线时较高，但在心脏手术前立即接受CEA的患者在CPB期间的COx和rScO2测量值与无明显狭窄的患者相似，而未矫正狭窄的患者有自动调节受损和较低rScO2的证据。这些初步结果提示COx可能有助于CEA患者的选择以及手术期间的个体患者管理。
