Kougias Panos, Sharath Sherene, Barshes Neal R, Chen Millie, Mills Joseph L
Michael E. DeBakey VA Medical Center, Houston, Tex; Division of Vascular Surgery and Endovascular Therapy, Baylor College of Medicine, Houston, Tex.
Michael E. DeBakey VA Medical Center, Houston, Tex; Division of Vascular Surgery and Endovascular Therapy, Baylor College of Medicine, Houston, Tex.
J Vasc Surg. 2017 Dec;66(6):1836-1843. doi: 10.1016/j.jvs.2017.05.113. Epub 2017 Sep 22.
Published data suggest that permissive anemia strategies that allow nadir hemoglobin (nHb) values of 7 g/dL or lower are safe in a variety of clinical settings. The appropriateness of these strategies in patients at high risk for adverse postoperative cardiac events remains unclear. We sought to determine the combined effect of postoperative nHb and cardiac risk status on major complications after vascular surgical interventions.
This was a single-institution retrospective analysis of consecutive patients who underwent elective open procedures for occlusive vascular disease and aneurysm repair, either open or endovascular. The Revised Cardiac Risk Index (RCRI) was used to assess baseline cardiac risk. Primary outcome was a composite end point of mortality or major ischemic events (myocardial infarction, stroke, acute kidney injury, or coronary revascularization) within 90 days from the index operation. Secondary outcomes included intensive care unit (ICU) length of stay (LOS) and 90-day respiratory complications (pneumonia, ventilator dependence for >48 hours postoperatively, or reintubation). Hierarchical multivariable regression was used to model each outcome with adjustment for age, type of operation, baseline comorbidities, and intraoperative covariates.
We analyzed 2508 operations performed during 8 years in 2106 patients with a mean age of 67 years (range, 45-90 years). In the fully adjusted multivariable model, lower values of nHb increased the risk of the primary composite end point (odds ratio [OR], 1.24; P < .001, representing a 24% increase in the odds of the composite end point for each 1-g/dL increase in nHb). In the same model, RCRI class II (OR, 1.8; P < .001), class III (OR, 2.06; P < .0001), and class IV (OR, 2.35; P < .0001) were associated with progressively increasing odds of the composite end point compared with RCRI class I. An interaction term between transfusion and nHb was not significant statistically, indicating that the harmful effect of anemia was independent of blood transfusion. Lower values of nHb also increased the risk of respiratory complications (OR, 1.41; P = .002) and ICU LOS (average 2.6-day increase per 1-g/dL increase of nHb; P < .0001).
Postoperative anemia increases the rate of early postoperative mortality and major ischemic events, particularly in patients at higher baseline cardiac risk. It also adversely affects respiratory complications and ICU LOS. Until a randomized trial definitively settles the issue, restrictive transfusion strategies should be practiced with caution in patients undergoing major vascular interventions.
已发表的数据表明，在各种临床环境中，允许最低血红蛋白（nHb）值降至7 g/dL或更低的宽松贫血策略是安全的。这些策略在术后发生心脏不良事件风险较高的患者中是否适用尚不清楚。我们试图确定术后nHb和心脏风险状态对血管外科手术后主要并发症的综合影响。
这是一项单机构回顾性分析，研究对象为连续接受择期开放性手术治疗闭塞性血管疾病和动脉瘤修复（开放或血管内修复）的患者。采用修订心脏风险指数（RCRI）评估基线心脏风险。主要结局是指从指数手术起90天内死亡或主要缺血事件（心肌梗死、中风、急性肾损伤或冠状动脉血运重建）的复合终点。次要结局包括重症监护病房（ICU）住院时间（LOS）和90天呼吸并发症（肺炎、术后呼吸机依赖>48小时或再次插管）。采用分层多变量回归对每个结局进行建模，并对年龄、手术类型、基线合并症和术中协变量进行调整。
我们分析了2106例患者在8年内进行的2508例手术，患者平均年龄67岁（范围45 - 90岁）。在完全调整的多变量模型中，nHb值较低会增加主要复合终点的风险（比值比[OR]，1.24；P <.001，意味着nHb每增加1 g/dL，复合终点的比值增加24%）。在同一模型中，与RCRI I级相比，RCRII级（OR，1.8；P <.001）、III级（OR，2.06；P <.0001）和IV级（OR，2.35；P <.0001）与复合终点的比值逐渐增加相关。输血与nHb之间的交互项在统计学上不显著，表明贫血的有害影响与输血无关。nHb值较低还会增加呼吸并发症的风险（OR，1.41；P =.002）和ICU住院时间（nHb每增加1 g/dL，平均增加2.6天；P <.0001）。
术后贫血会增加术后早期死亡率和主要缺血事件的发生率，尤其是基线心脏风险较高的患者。它还会对呼吸并发症和ICU住院时间产生不利影响。在随机试验明确解决该问题之前，对于接受重大血管干预的患者，应谨慎采用限制性输血策略。
