中文摘要

研究背景

越来越多的证据表明，术中低血压（Intraoperative Hypotension，IOH）作为一个可调控的危险因素，与术后神经系统并发症的发生有关，降低其发生率可能对于预防围手术期中枢神经系统并发症、改善患者预后具有重要意义，但二者之间的关系仍不明确。非体外循环冠状动脉旁路移植术（Off-Pump Coronary Artery Bypass Grafting，OPCABG）具有减少体外循环手术后不良反应、加快患者术后恢复的优点，但部分患者手术后仍然出现神经系统并发症，降低患者的生活质量并严重影响患者的预后。

研究目的

研究术中低血压与OPCABG术后神经系统并发症（Neurological Complication，NC）的相关性。

研究方法

回顾性收集我院2023年4月至2024年4月期间择期行非体外循环下冠状动脉旁路移植术的患者1006例，根据术中平均动脉血压（Mean Arterial Pressure，MAP）是否低于55mmhg且至少持续5分钟分为低血压组和非低血压组，分析OPCABG期间术中低血压、低血压临界值的曲线下面积（Area Under the Curve，AUC）以及低血压不同累计时间与术后7天内神经系统并发症的关系。 

研究结果

本研究共纳入患者1006例。低血压组和非低血压组术后7天内神经系统并发症的发生率分别为6.1%（23/374）、3.6%（23/632），术后缺血性脑卒中的发生率分别为2.9%（11/374）、0.6%（4/632），术后谵妄的发生率分别为1.9%（7/374）、1.9%（12/632），术后认知功能障碍的发生率分别为1.6%（6/374）、1.1%（7/632）。

低血压组患者术后缺血性脑卒中的发生率是非低血压组的4.647倍( RR=4.647，95% CI: 1.490 -14.490 ，P = 0. 004)；多因素Logistic回归分析结果显示，术中低血压是术后缺血性脑卒中的独立危险因素( OR = 5.418，95% CI: 1.657 - 17.716，P = 0.005 )。

按术中低血压AUC的中位数（Q2=64.360mmHg•min）分组，多因素Logistic 回归分析结果显示：与非低血压组相比，AUC＜64.35mmHg•min组术后缺血性脑卒中发生风险增加约5.922倍( ORadj =5.922， 95 % CIadj: 1.604-21.861， P =0.008 )；AUC≥64.35mmHg•min组术后缺血性脑卒中发生风险增加约4.909倍( ORadj =4.909， 95 % CIadj: 1.263 -19.079， P =0.022 )。

按术中低血压累计时间分层后，多因素Logistic回归分析结果显示：与非低血压组（累计时间= 0 min）相比，短时间低血压组（ 5 min ≤累计时间< 15 min）术后总体神经系统并发症的发生风险增加（ORadj = 1.904，95% CIadj: 1.011-3.587，P = 0.046），术后缺血性脑卒中的发生风险亦显著增加（ORadj = 6.739，95% CIadj: 2.020-22.481，P = 0.002）；未发现长时间低血压组（累计时间≥15min）术后神经系统并发症发生风险增加。

研究结论

本研究发现，OPCABG术中平均动脉压低于55mmHg，5分钟≤累积时间＜15分钟增加术后缺血性脑卒中的发生率，累计时间≥15分钟不增加缺血性脑卒中的发生率；未发现术中平均动脉压低于55mmHg与术后认知功能障碍和术后谵妄的相关性。

关键词：非体外循环下冠状动脉旁路移植术、全身麻醉、术中低血压、术后神经系统并发症

Abstract
Background
Off-pump coronary artery bypass grafting (OPCABG) is recognized for its advantages in reducing the adverse reactions associated with extracorporeal circulation and accelerating postoperative recovery in patients. However, some patients still suffer from neurological complications following surgery. Neurological disorders are among the most common complications following cardiac and major vascular surgery, with temporary or permanent neurological deficits significantly diminishing the quality of life and adversely affecting patient outcomes. A growing body of evidence suggests that intraoperative hypotension (IOH) is associated with the occurrence of postoperative neurological complications. As IOH is a modifiable risk factor, reducing its incidence may be crucial for preventing perioperative central nervous system complications and improving patient prognosis. Nevertheless, the relationship between common postoperative neurological complications and intraoperative hypotension remains to be elucidated.
Objective
To investigate the correlation between intraoperative hypotension (IOH) and neurological complications (NC) following OPCABG.
Methods
A retrospective study was conducted, collecting data from 1006 elective OPCABG patients at our institution between April 2023 and April 2024. Patients were categorized into hypotension and non-hypotension groups based on whether their mean arterial pressure (MAP) dropped below 55 mmHg for a duration of at least 5 minutes during surgery. The study analyzed the relationship between intraoperative hypotension, the area under the curve (AUC) at threshold values of IOH , and the duration of IOH with early postoperative (within 7 days) neurological complications, as well as identifying associated risk factors.
Results
A total of 1006 patients were included in this study. The incidence of neurological complications within 7 days after operation was 6.1% (23/374) in hypotension group and 3.6% (23/632) in non-hypotension group. The incidence of postoperative ischemic stroke was 2.9% (11/374) in hypotension group and 0.6% (4/632) in non-hypotension group. The incidence of postoperative delirium was 1.9% (7/374) and 1.9% (12/632), and the incidence of postoperative cognitive dysfunction was 1.6% (6/374) and 1.1% (7/632), respectively.
The incidence of postoperative ischemic stroke in hypotension group was 4.647 times higher than that in non-hypotension group (RR=4.647, 95%CI: 1.490-14.490, P = 0. 004). Multivariate Logistic regression analysis showed that intraoperative hypotension was an independent risk factor for postoperative ischemic stroke (OR = 5.418, 95%CI: 1.657-17.716, P = 0.005).
Grouped by the median area under the curve (AUC) of intraoperative hypotension (Q2=64.360mmHg•min), multivariate Logistic regression analysis showed that: Compared with the non-hypotension group, the risk of postoperative ischemic stroke in the AUC < 64.35mmHg•min group increased about 5.922 times (ORadj =5.922, 95% CIadj: 1.604-21.861, P =0.008). The risk of postoperative ischemic stroke increased about 4.909 times in AUC≥64.35mmHg•min group (ORadj =4.909, 95% CIadj: 1.263-19.079, P =0.022).
After stratification by different cumulative time, multivariate Logistic regression analysis showed that: Compared with the non-hypotension group (cumulative time=0min), the short-term hypotension group ( 5min≤cumulative time<15min) had an increased risk of postoperative overall neurological complications and postoperative ischemic stroke (ORadj=1.904, 95% CIadj: 1.011-3.587, P = 0.046; ORadj =6.739, 95% CIadj: 2.020-22.481, P = 0.002).No increase in the risk of neurological complications was found in the long-term hypotension group (cumulative time ≥15min).
Conclusions
In this study, it was found that the mean arterial pressure during OPCABG operation was lower than 55 mmHg, and the incidence of postoperative ischemic stroke was increased after 5 minutes ≤ cumulative time < 15 minutes, while the cumulative time ≥15 minutes did not increase the incidence of ischemic stroke. Our analysis revealed no significant association between postoperative cognitive dysfunction and postoperative delirium in the context of intraoperative mean arterial pressure lower than 55 mmHg.
Key words：
Off-Pump Coronary Artery Bypass Grafting; General Anesthesia; Intraoperative Hypotension; Postoperative Neurological Complications