Section of Vascular Surgery, Dartmouth-Hitchcock Medical Center, Lebano, NH 03765, USA.
J Vasc Surg. 2010 Jan;51(1):71-8. doi: 10.1016/j.jvs.2009.07.123. Epub 2009 Nov 24.
Using 30-day operative mortality reported with lower extremity bypass (LEB) in preoperative decision making may underestimate the actual death rate encountered before patients have truly recovered from surgery, especially in elderly, debilitated patients with significant tissue loss. Therefore, we examined preoperative, patient-level risk factors that predict survival within the first year following LEB.
Using our regional quality improvement initiative in 11 hospitals in Northern New England, we studied 2306 LEB procedures performed in 2031 patients between January 2003 and December 2007. Sixty surgeons contributed to our database, and over 100 demographic and clinical variables were abstracted by trained researchers. Cox proportional hazards models were used to generate hazard ratios (HR) and surrounding 95% confidence intervals (CI) for our combined outcome measure of death occurring within the first year postoperatively.
We found that within our cohort of 2306 bypass procedures, 11% of patients died within 1 year of surgery (2% prior to discharge, 9% prior to 1-year follow-up). We identified six preoperative patient characteristics associated with higher risk of death in multivariate analysis: congestive heart failure (HR 1.3, 95% CI 1.0-1.8), diabetes (HR 1.5, 95% CI 1.1-2.1), critical limb ischemia (CLI) (HR 1.7, 95% CI 1.3-2.4), lack of single-segment saphenous vein (HR 1.9, 95% CI 1.5-2/5), age over 80 (HR 2.0, 95% CI 1.5-2.7), dialysis dependence (HR 2.7, 95% CI 1.9-3.6), and emergent nature of the procedure (HR 3.4, 95% CI 1.7-6.8). While patients with no risk factors had 1-year death rates that were less than 5%: patients with three or more risk factors had a 28% chance of dying before 1 year postoperatively. When we compared risk-adjusted survival across centers, we found that one center in our region performed significantly better than expected (observed-to-expected outcome ratio 0.7, 95% CI 0.6-0.9, P = .04).
Preoperative risk factors allow surgeons to predict survival in the first year following LEB, and to more precisely inform patients about their operative risk with LEB. Additionally, our model facilitates benchmarking comparison of risk-adjusted outcomes across our region. We believe quality improvement measures such as these will allow surgeons to identify best practices and thereby improve outcomes with LEB across centers.
在术前决策中使用报告的下肢旁路术（LEB）的 30 天手术死亡率可能会低估患者在真正从手术中恢复之前遇到的实际死亡率，尤其是在患有严重组织损失的老年、虚弱的患者中。因此，我们研究了预测 LEB 后第一年生存的术前患者水平的危险因素。
利用我们在新英格兰北部 11 家医院的区域质量改进计划，我们研究了 2003 年 1 月至 2007 年 12 月期间 2031 名患者的 2306 例 LEB 手术。60 名外科医生为我们的数据库做出了贡献，由经过培训的研究人员提取了超过 100 个人口统计学和临床变量。使用 Cox 比例风险模型生成我们的综合术后 1 年内死亡的合并结局指标的风险比（HR）和周围 95%置信区间（CI）。
我们发现，在我们的 2306 例旁路手术队列中，11%的患者在手术后 1 年内死亡（2%在出院前，9%在 1 年随访前）。在多变量分析中，我们确定了六个与死亡风险较高相关的术前患者特征：充血性心力衰竭（HR 1.3，95%CI 1.0-1.8）、糖尿病（HR 1.5，95%CI 1.1-2.1）、严重肢体缺血（CLI）（HR 1.7，95%CI 1.3-2.4）、缺乏单段大隐静脉（HR 1.9，95%CI 1.5-2/5）、年龄超过 80 岁（HR 2.0，95%CI 1.5-2.7）、依赖透析（HR 2.7，95%CI 1.9-3.6）和手术的紧急性质（HR 3.4，95%CI 1.7-6.8）。虽然没有危险因素的患者 1 年死亡率低于 5%：但有三个或更多危险因素的患者在术后 1 年内死亡的几率为 28%。当我们比较跨中心的风险调整生存时，我们发现该地区的一个中心的表现明显优于预期（观察到的与预期结果比值为 0.7，95%CI 0.6-0.9，P=0.04）。
术前危险因素使外科医生能够预测 LEB 后第一年的生存，并更准确地向患者告知 LEB 的手术风险。此外，我们的模型便于对我们地区的风险调整结果进行基准比较。我们相信，此类质量改进措施将使外科医生能够确定最佳实践，并因此提高各中心的 LEB 结果。
