Zettervall Sara L, Soden Peter A, Ultee Klaas H J, Seldon Crystal, Oh Jinhee, McGann Kevin, Schermerhorn Marc L, Guzman Raul J
Division of Vascular and Endovascular Surgery, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Mass; Department of Surgery, George Washington University Medical Center, Washington, D.C.
Division of Vascular and Endovascular Surgery, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Mass.
J Vasc Surg. 2017 Feb;65(2):431-437. doi: 10.1016/j.jvs.2016.06.097. Epub 2016 Sep 22.
Elevated serum phosphate levels have been associated with increased risks of cardiovascular events and death in several patient populations. The effects of serum phosphate on outcomes in patients with critical limb ischemia (CLI) have not been evaluated. In this study, we assessed the effect of abnormal phosphate levels on mortality and major limb events after surgical intervention for CLI.
A retrospective review was undertaken to identify all patients at a single institution who underwent a first-time open or endovascular intervention for CLI between 2005 and 2014. Patients without recorded postoperative phosphate levels were excluded. Postoperative phosphate levels ≤30 days of the initial operation were recorded, and the mean was calculated. Patients were stratified according to mean phosphate levels (low: <2.5 mg/dL, normal: 2.5-4.5 mg/dL, and high: >4.5 mg/dL). Patient demographics, comorbidities, and operative details were compared in univariate analysis. Multivariable regression and Cox proportional hazard modeling were used to account for patient demographics and comorbid conditions.
We identified 941 patients, including 42 (5%) with low phosphate, 768 (82%) with normal phosphate, and 131 (14%) with high phosphate. Patients with elevated phosphate were younger and had higher rates of congestive heart failure, diabetes, and dialysis dependence. Bypass was more common among patients with normal phosphate compared with high or low phosphate levels. There was no difference in the Wound, ischemia, and Foot infection (WiFi) classification or TransAtlantic Inter-Society Consensus classification among the cohorts. There were significant differences in 1-year mortality (low: 19%, normal: 17%, high: 33%; P < .01) and 3-year mortality (low: 38%, normal: 34%, high: 56%; P < .01) between phosphate cohorts. Major amputation (low: 12%, normal: 12%, high: 15%) and restenosis (low: 21%, normal: 24%, high: 28%) tended toward worse outcomes among patients with elevated phosphate levels but did not reach statistical significance. After adjustment for baseline characteristics, mortality was higher (hazard ratio [HR], 1.7; 95% confidence interval [CI], 1.3-2.2) and amputation-free survival was lower (HR, 1.5; 95% CI, 1.2-1.9) among patients with elevated compared with normal phosphate levels. A subgroup analysis was then performed to assess dialysis and nondialysis patients separately. Patients with elevated serum phosphate levels maintained a significantly higher risk of mortality in each group (dialysis: HR, 1.8; 95% CI, 1.2-2.6; nondialysis: HR, 1.5; 95% CI, 1.04-2.10).
Elevated phosphate levels are associated with increased mortality and decreased amputation-free survival after interventions for CLI. Future studies evaluating the effects of phosphate reduction in patients with CLI are warranted.
在多个患者群体中，血清磷酸盐水平升高与心血管事件及死亡风险增加相关。血清磷酸盐对严重肢体缺血（CLI）患者预后的影响尚未得到评估。在本研究中，我们评估了异常磷酸盐水平对CLI手术干预后死亡率和主要肢体事件的影响。
进行一项回顾性研究，以确定2005年至2014年间在单一机构首次接受CLI开放手术或血管内介入治疗的所有患者。排除术后磷酸盐水平未记录的患者。记录初次手术后≤30天的磷酸盐水平，并计算平均值。根据平均磷酸盐水平对患者进行分层（低：<2.5mg/dL，正常：2.5 - 4.5mg/dL，高：>4.5mg/dL）。在单因素分析中比较患者的人口统计学、合并症和手术细节。使用多变量回归和Cox比例风险模型来考虑患者的人口统计学和合并症情况。
我们确定了941例患者，其中42例（5%）磷酸盐水平低，768例（82%）磷酸盐水平正常，131例（14%）磷酸盐水平高。磷酸盐水平升高的患者更年轻，充血性心力衰竭、糖尿病和透析依赖的发生率更高。与磷酸盐水平高或低的患者相比，正常磷酸盐水平的患者更常进行旁路手术。各队列之间的伤口、缺血和足部感染（WiFi）分类或跨大西洋跨学会共识分类没有差异。磷酸盐水平不同的队列之间，1年死亡率（低：19%，正常：17%，高：33%；P <.01）和3年死亡率（低：38%，正常：34%，高：56%；P <.01）存在显著差异。主要截肢（低：12%，正常：12%，高：15%）和再狭窄（低：21%，正常：24%，高：28%）在磷酸盐水平升高的患者中预后往往更差，但未达到统计学意义。在对基线特征进行调整后，与磷酸盐水平正常的患者相比，磷酸盐水平升高的患者死亡率更高（风险比[HR]，1.7；95%置信区间[CI]，1.3 - 2.2），无截肢生存率更低（HR，1.5；95% CI，1.2 - 1.9）。然后进行亚组分析，分别评估透析患者和非透析患者。血清磷酸盐水平升高的患者在每组中死亡率风险均显著更高（透析：HR，1.8；95% CI，1.2 - 2.6；非透析：HR，1.5；95% CI，1.04 - 2.10）。
磷酸盐水平升高与CLI干预后死亡率增加和无截肢生存率降低相关。有必要开展进一步研究评估降低CLI患者磷酸盐水平的效果。
