Department of Cardiovascular Surgery, University Hospital Giessen, and Department of Medical Statistics, University of Giessen, Giessen, Germany.
Ann Thorac Surg. 2011 Sep;92(3):805-10. doi: 10.1016/j.athoracsur.2011.02.076. Epub 2011 May 18.
A negative relationship between anemia before coronary artery bypass graft (CABG) surgery and the perioperative mortality has been shown. We tried to clarify whether anemia only expresses an increased perioperative risk or is a risk factor per se in a two-institution database.
In the years 2005 and 2006, 185 of 3,311 patients undergoing isolated first-time CABG surgery had anemia defined as hematocrit less than 33% or Hb≤11 g/dL. Preoperative and postoperative data of patients having anemia and patients having normal hematocrit were compared using χ2-tests or Fisher's exact tests regarding structural group differences. To determine factors influencing perioperative mortality, methods of logistic regression were used.
The 30-day mortality of anemic patients (12.9%) was significantly higher (p<0.001) than the mortality of nonanemic patients (2.2%). Patients having anemia, though, had a worse risk profile before surgery: high European System for Cardiac Operative Risk Evaluation values (median, 7 in anemic patients versus 4 in nonanemic patients), acute myocardial infarction (9.7% in anemic versus 2% in nonanemic patients), diabetes mellitus (45.4% in anemic versus 33.3% in nonanemic patients), and cardiogenic shock (5.4% in anemic versus 0.8% in nonanemic patients) were significantly more frequent in the anemic group. However, taking these risks in account, the logistic regression revealed preoperative anemia still to be a mortality-increasing factor in patients undergoing CABG surgery (odds ratio 3.727, confidence interval: 2.196 to 6.324). Furthermore, anemia was a risk factor for perioperative morbidity (major adverse cardiovascular events) after CABG surgery (odds ratio 2.199, confidence interval: 1.423 to 3.397).
In our patient group undergoing CABG surgery, preoperative anemia increased the mortality risk by 3.4, even when taking the higher perioperative risk of anemic patients into consideration.
冠状动脉旁路移植术（CABG）前贫血与围手术期死亡率呈负相关。我们试图在一个两机构数据库中阐明贫血是否仅表现出增加的围手术期风险，还是本身就是一个危险因素。
在 2005 年和 2006 年，对 185 名接受首次 CABG 手术的孤立患者进行了研究，这些患者的贫血定义为血细胞比容<33%或 Hb≤11g/dL。使用卡方检验或 Fisher 精确检验比较贫血患者和血细胞比容正常患者的术前和术后数据，以确定结构组差异。为了确定影响围手术期死亡率的因素，使用逻辑回归方法。
贫血患者（12.9%）的 30 天死亡率明显高于非贫血患者（2.2%）（p<0.001）。尽管如此，贫血患者术前的风险状况更差：欧洲心脏手术风险评估系统（EuroSCORE）值较高（中位数，贫血患者为 7，非贫血患者为 4），急性心肌梗死（贫血患者为 9.7%，非贫血患者为 2%），糖尿病（贫血患者为 45.4%，非贫血患者为 33.3%）和心源性休克（贫血患者为 5.4%，非贫血患者为 0.8%）在贫血组中更为常见。然而，考虑到这些风险，逻辑回归显示术前贫血仍然是 CABG 手术患者死亡率增加的一个因素（优势比 3.727，置信区间：2.196 至 6.324）。此外，贫血是 CABG 手术后围手术期发病率（主要不良心血管事件）的危险因素（优势比 2.199，置信区间：1.423 至 3.397）。
在我们的 CABG 手术患者群体中，即使考虑到贫血患者更高的围手术期风险，术前贫血也会使死亡率增加 3.4 倍。
