Magnetic Resonance Imaging Based Calf Muscle Perfusion To Assess Patients With Symptomatic Peripheral Artery Disease

摘要： 外周动脉疾病（PAD）与腿部功能受损、可能的肢体丧失和增加的 心血管事件的风险。间歇性跛行（IC）是一种典型的PAD症状， 有症状的患者，并与5年和15年的死亡率分别为30%和70%。 PAD是一种使人衰弱的疾病，影响超过850万40岁及以上的美国人， 全球的人。尽管患病率很高，但PAD患者不太可能接受适当的治疗， 其动脉粥样硬化危险因素高于冠心病患者。血管内治疗进展 降低了与介入相关的风险，使血运重建成为患者的常规手术 下肢缺血然而，血运重建成功率差异很大，许多PAD 尽管技术上良好的血运重建，患者在1年时没有改善。先前的研究结果表明， 由于侧支缺乏而引起的微循环改变可能会导致 PAD患者。我们假设微血管灌注的变化可以识别出PAD患者， 血运重建后12个月未改善。我们会用对比增强磁共振 通过CE-MRI评估PAD患者的骨骼肌灌注。CE-MRI测量将是 与血流动力学和症状相关。早期识别可能贫困的个人 干预后的预后有助于改善外科治疗策略。我们将调查 微血管灌注（目的1）和动脉血流动力学测量（目的2）与下肢的相关性 功能和PAD症状。我们将利用机器学习方法来确定腿部不佳的预测因素 功能和症状（目标3）。鉴于PAD的高发病率和相关的高风险， 心血管事件，最重要的是要确定谁是不太可能改善以下低 肢体血运重建这项临床影像学研究的数据将提供新的信息的病因 PAD中的微血管血流。

Abstract: Peripheral artery disease (PAD) is associated with impaired leg function, possible limb loss and an increased risk of cardiovascular events. Intermittent claudication (IC) is a classic PAD symptom occurring in 40% of symptomatic patients, and is associated with 5-, and 15-year mortality rates of 30% and 70%, respectively. PAD is a debilitating illness affecting more than 8.5 million Americans of age 40 and older and 202 million people globally. Despite the high prevalence, PAD patients are less likely to receive appropriate treatment for their atherosclerotic risk factors than patients with coronary artery disease. Advances in endovascular therapy have reduced risks associated with intervention, enabling revascularization as a routine procedure in patients with lower extremity ischemia. However, revascularization success rates vary substantially and numerous PAD patients do not improve at 1-year despite technically good revascularization. Previous findings suggest that alterations in the microcirculation due to a paucity of collateralization may contribute to functional impairment in PAD patients. We hypothesize that the change in microvascular perfusion can identify PAD patients who do not improve at 12-months after revascularization. We will utilize contrast-enhanced magnetic resonance imaging (CE-MRI) to assess skeletal muscle perfusion in PAD patients. The CE-MRI measures will be associated with hemodynamics and symptoms. The early identification of individuals with a likely poor prognosis post intervention could help to improve surgical treatment strategies. We will investigate the association of microvascular perfusion (Aim 1) and measures of arterial hemodynamics (Aim 2) with leg function and PAD symptoms. We will utilize machine learning methodologies to identify predictors of poor leg function and symptoms (Aim 3). Given the high incidence of PAD and the associated high risk of cardiovascular events, it is paramount to identify individuals who are less likely to improve following lower extremity revascularization. The data of this clinical imaging study will provide novel information on the etiology of microvascular blood flow in PAD.