Hammad Tarek A, Hiatt William R, Gornik Heather L, Shishehbor Mehdi H
1 Division of Cardiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
2 Division of Cardiology, University of Colorado School of Medicine and CPC Clinical Research, Aurora, CO, USA.
Vasc Med. 2017 Jun;22(3):204-209. doi: 10.1177/1358863X16676902. Epub 2016 Dec 1.
Prior studies have assessed the prognostic value of a decrease, not an increase, of the post-exercise ankle-brachial index (ABI) among patients with normal resting results. Thus, we sought to evaluate the prognostic significance of an increase in post-exercise ABI among these patients. From a single center vascular laboratory database between September 2005 and January 2010, we retrospectively identified 1437 consecutive patients with a normal resting ABI (1.00-1.40) and available post-exercise results. We classified them into group 1 (normal subjects; post-exercise ABI drop ⩽ 20%, 58%) and group 2 (post-exercise ABI increase, 42%) after excluding those with an ABI drop > 20% (peripheral artery disease) as they had known disease ( n=192). The primary outcome was to assess the risk of ischemic events, defined as a composite of unadjudicated death, stroke, or myocardial infraction (MACE). Associations between groups and outcomes were examined using multivariable Cox proportional hazard and propensity analyses. Both groups had similar prevalence of cardiovascular comorbidities. In unadjusted analysis, group 2 was more likely to have MACE ( p = 0.001). After adjusting for all baseline characteristics, an increase in post-exercise ABI compared to normal subjects was associated with a higher MACE (adjusted HR: 1.70, 95% CI: 1.14-2.53; p=0.009). This association stayed statistically significant after propensity matching (adjusted HR: 1.80, 95% CI: 1.17-2.76; p=0.007). This hypothesis-generating analysis showed that an increase in post-exercise ABI appears to identify a population with a higher risk for MACE. A prospective study of this association and mechanisms of risk should be conducted.
先前的研究评估了静息结果正常的患者运动后踝臂指数（ABI）降低而非升高的预后价值。因此，我们试图评估这些患者运动后ABI升高的预后意义。从2005年9月至2010年1月的一个单中心血管实验室数据库中，我们回顾性地确定了1437例静息ABI正常（1.00 - 1.40）且有运动后结果的连续患者。在排除ABI下降>20%（外周动脉疾病）的患者（n = 192）后，因为他们患有已知疾病，我们将其余患者分为第1组（正常受试者；运动后ABI下降⩽20%，58%）和第2组（运动后ABI升高，42%）。主要结局是评估缺血性事件的风险，定义为未经判定的死亡、中风或心肌梗死（MACE）的复合事件。使用多变量Cox比例风险模型和倾向分析来检验组与结局之间的关联。两组心血管合并症的患病率相似。在未调整分析中，第2组发生MACE的可能性更大（p = 0.001）。在对所有基线特征进行调整后，与正常受试者相比，运动后ABI升高与更高的MACE风险相关（调整后HR：1.70，95%CI：1.14 - 2.53；p = 0.009）。在倾向匹配后，这种关联在统计学上仍然显著（调整后HR：1.80，95%CI：1.17 - 2.76；p = 0.007）。这项产生假设的分析表明，运动后ABI升高似乎可识别出发生MACE风险较高的人群。应该对这种关联及其风险机制进行前瞻性研究。
