Hallqvist Linn, Granath Fredrik, Fored Michael, Bell Max
From the Department of Perioperative Medicine and Intensive Care (PMI), Karolinska University Hospital, Stockholm, Sweden.
Department of Pharmacology and Physiology, Karolinska Institutet, Stockholm, Sweden.
Anesth Analg. 2021 Jul 1;133(1):6-15. doi: 10.1213/ANE.0000000000005391.
Hemodynamic instability during anesthesia and surgery is common and associated with cardiac morbidity and mortality. Information is needed regarding optimal blood pressure (BP) threshold in the perioperative period. Therefore, the effect of intraoperative hypotension (IOH) on risk of perioperative myocardial infarction (MI) was explored.
A nested case-control study with patients developing MI <30 days postsurgery matched with non-MI patients, sampled from a large surgery cohort. Study participants were adults undergoing noncardiac surgery at 3 university hospitals in Sweden, 2007-2014. Matching criteria were age, sex, American Society of Anesthesiologists (ASA) physical status, cardiovascular disease, hospital, year-, type-, and extent of surgery. Medical records were reviewed to validate MI diagnoses and retrieve information on comorbid history, baseline BP, laboratory and intraoperative data. Main exposure was IOH, defined as a decrease in systolic blood pressure (SBP), in mm Hg, from preoperative individual resting baseline lasting at least 5 minutes. Outcomes were acute MI, fulfilling the universal criteria, subclassified as type 1 and 2, occurring within 30 days and mortality beyond 30 days among case and control patients. Conditional logistic regression assessed the association between IOH, decrease in SBP from individual baseline, and perioperative MI. Mortality rates were estimated using Cox proportional hazards. Relative risk estimates are reported as are the corresponding absolute risks derived from the well-characterized source population.
A total of 326 cases met the inclusion criteria and were successfully matched with 326 controls. The distribution of MI type was 59 (18%) type 1 and 267 (82%) type 2. Median time to MI diagnosis was 2 days; 75% were detected within a week of surgery. Multivariable analysis acknowledged IOH as an independent risk factor of perioperative MI. IOH, with reduction of 41-50 mm Hg, from individual baseline SBP, was associated with a more than tripled increased odds, odds ratio (OR) = 3.42 (95% confidence interval [CI], 1.13-10.3), and a hypotensive event >50 mm Hg with considerably increased odds in respect to MI risk, OR = 22.6, (95% CI, 7.69-66.2). In patients with a very high-risk burden, the absolute risk of an MI diagnosis increased from 3.6 to 68 per 1000 surgeries.
In patients undergoing noncardiac surgery, IOH is a possible contributor to clinically significant perioperative MI. The high absolute MI risk associated with IOH, among a growing population of patients with a high-risk burden, suggests that increased vigilance of BP control in these patients may be beneficial.
麻醉和手术期间的血流动力学不稳定很常见，且与心脏发病率和死亡率相关。围手术期需要有关最佳血压（BP）阈值的信息。因此，探讨了术中低血压（IOH）对围手术期心肌梗死（MI）风险的影响。
一项巢式病例对照研究，从一个大型手术队列中抽取术后<30天发生MI的患者与未发生MI的患者进行匹配。研究参与者为2007年至2014年在瑞典3所大学医院接受非心脏手术的成年人。匹配标准为年龄、性别、美国麻醉医师协会（ASA）身体状况、心血管疾病、医院、年份、手术类型和范围。查阅病历以验证MI诊断，并获取合并症病史、基线血压、实验室和术中数据等信息。主要暴露因素为IOH，定义为收缩压（SBP）从术前个体静息基线下降至少5分钟，以毫米汞柱为单位。结局指标为符合通用标准的急性MI，分为1型和2型，在病例组和对照组患者中30天内发生的情况以及30天后的死亡率。采用条件逻辑回归评估IOH、SBP从个体基线下降与围手术期MI之间的关联。使用Cox比例风险模型估计死亡率。报告相对风险估计值以及从特征明确的源人群得出的相应绝对风险。
共有326例病例符合纳入标准，并成功与326例对照匹配。MI类型分布为1型59例（18%），2型267例（82%）。MI诊断的中位时间为2天；75%在术后一周内被检测到。多变量分析确认IOH是围手术期MI的独立危险因素。IOH使SBP从个体基线下降41 - 50毫米汞柱，与MI风险增加三倍以上相关，比值比（OR）= 3.42（95%置信区间[CI]，1.13 - 10.3），而低血压事件>50毫米汞柱时，MI风险的比值比显著增加，OR = 22.6（95% CI，7.69 - 66.2）。在高风险负担患者中，MI诊断的绝对风险从每1000例手术3.6例增加到68例。
在接受非心脏手术的患者中，IOH可能是导致具有临床意义的围手术期MI的一个因素。在高风险负担患者群体中，IOH与高绝对MI风险相关，这表明提高对这些患者血压控制的警惕性可能有益。
