BACKGROUND: 

The risk of myocardial injury progressively increases at intraoperative mean arterial pressures (MAPs) ≤65 mm Hg. Higher pressures might be required in chronically hypertensive patients. We aimed to test the hypothesis that the harm threshold is higher in patients with chronic hypertension than in normotensive patients.

METHODS: 

We conducted a single-center retrospective cohort analysis of adults >45 years old who had noncardiac surgery between 2010 and 2018 and scheduled, rather than symptom-driven, postoperative troponin measurements. The MAP thresholds under which risk started to increase were compared between patients with chronic hypertension (baseline MAP ≥110 mm Hg) and normotensive patients (baseline MAP <110 mm Hg). The primary outcome was a composite of in-hospital mortality and myocardial injury within 30 days, defined by any postoperative 4th-generation troponin T measurement ≥0.03 ng/mL apparently due to cardiac ischemia. Multivariable logistic regression and moving average smoothing methods were used to evaluate confounder-adjusted associations between the composite outcome and the lowest intraoperative MAP sustained for either 5 or 10 cumulative minutes, and whether the relationship depended on baseline pressure (normotensive versus hypertensive).

RESULTS: 

Among 4576 eligible surgeries, 2066 were assigned to the normotensive group with mean (standard deviation [SD]) baseline MAP of 100 (7) mm Hg, and 2510 were assigned to the hypertensive group with mean baseline MAP of 122 (10) mm Hg. The overall incidence of the composite outcome was 5.6% in normotensive and 6.0% in hypertensive patients (P = .55). The relationship between intraoperative hypotension and the composite outcome was not found to depend on baseline MAP in a multivariable mixed effects logistic regression model. Furthermore, no statistical change points were found for either baseline MAP group.

CONCLUSIONS: 

Baseline blood pressure of the hypertensive patients was only moderately increased on average, and the event rate was low. Nonetheless, we were not able to demonstrate a difference in the harm threshold between normotensive and chronically hypertensive patients. Our results do not support the theory that hypertensive patients should be kept at higher intraoperative pressures than normotensive patients.

中文翻译：

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伴有或不伴有慢性高血压的成人非心脏手术后的术中低血压和心肌损伤：回顾性队列分析

背景： 

术中平均动脉压 (MAP) ≤65 mm Hg 时，心肌损伤的风险逐渐增加。慢性高血压患者可能需要更高的压力。我们旨在检验慢性高血压患者的危害阈值高于血压正常患者的假设。

方法： 

我们对 2010 年至 2018 年期间接受过非心脏手术并安排而非症状驱动的术后肌钙蛋白测量的 > 45 岁的成年人进行了单中心回顾性队列分析。在慢性高血压患者（基线 MAP ≥110 mm Hg）和血压正常患者（基线 MAP <110 mm Hg）之间比较了风险开始增加的 MAP 阈值。主要结果是 30 天内院内死亡率和心肌损伤的复合结果，定义为任何术后第 4 代肌钙蛋白 T 测量值≥0.03 ng/mL，显然是由于心脏缺血所致。

结果： 

在 4576 例符合条件的手术中，2066 例被分配到平均基线 MAP 为 100 (7) mm Hg 的正常血压组，2510 例被分配到平均基线 MAP 为 122 (10) mm Hg 的高血压组. 复合结局的总发生率在正常血压患者和高血压患者中分别为 5.6% 和 6.0% ( P = .55)。在多变量混合效应逻辑回归模型中，未发现术中低血压与复合结局之间的关系取决于基线 MAP。此外，没有发现任何一个基线 MAP 组的统计变化点。

结论： 

高血压患者的基线血压平均仅适度升高，事件发生率较低。尽管如此，我们无法证明血压正常和慢性高血压患者之间的伤害阈值存在差异。我们的结果不支持高血压患者应保持比正常血压患者更高的术中压力的理论。