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用符号不匹配法鉴别有严重心血管风险的患者

Identifying Patients at Risk of Major Adverse Cardiovascular Events Using Symbolic Mismatch
课程网址: http://videolectures.net/nips2010_syed_ipr/  
主讲教师: Zeeshan Syed
开课单位: 密歇根大学
开课时间: 2011-01-13
课程语种: 英语
中文简介:
心血管疾病是全球死亡的主要原因,每年造成1700万人死亡。尽管存在各种治疗选择,但是基于传统医学知识的现有技术通常无法识别可能从更积极的治疗中受益的患者。在本文中,我们描述和评估一种新的无监督机器学习方法用于心脏危险分层。我们的方法的关键思想是避免专业医学知识,并使用符号错配评估患者风险,这是评估长期时间序列活动相似性的新指标。我们假设高风险患者可以使用符号错配来识别,作为具有不寻常的长期生理活动的人群中的个体。我们描述了基于这些想法的相关方法,以便为最近遭受冠状动脉发作的患者提供改进的医疗决策。我们首先描述如何计算长期心电图(ECG)信号对之间的符号不匹配。该算法将原始信号映射到符号域,并提供对原始信号的这些符号表示之间的差异的定量评估。然后,我们展示了如何将该度量与一类SVM,最近邻分类器和层次聚类中的每一个一起使用,以改善风险分层。我们使用可获得的长期心电图数据评估了我们对686名心脏病患者的方法。在单变量分析中,所有方法都提供了与未来90天内主要心脏不良事件发生的统计学显着相关性。在纳入最广泛使用的临床风险变量的多变量分析中,最近邻和分层聚类方法能够在统计学上显着区分在接下来的90天内患有严重心脏不良事件的风险大约两倍的患者。
课程简介: Cardiovascular disease is the leading cause of death globally, resulting in 17 million deaths each year. Despite the availability of various treatment options, existing techniques based upon conventional medical knowledge often fail to identify patients who might have benefited from more aggressive therapy. In this paper, we describe and evaluate a novel unsupervised machine learning approach for cardiac risk stratification. The key idea of our approach is to avoid specialized medical knowledge, and assess patient risk using symbolic mismatch, a new metric to assess similarity in long-term time-series activity. We hypothesize that high risk patients can be identified using symbolic mismatch, as individuals in a population with unusual long-term physiological activity. We describe related approaches that build on these ideas to provide improved medical decision making for patients who have recently suffered coronary attacks. We first describe how to compute the symbolic mismatch between pairs of long term electrocardiographic (ECG) signals. This algorithm maps the original signals into a symbolic domain, and provides a quantitative assessment of the difference between these symbolic representations of the original signals. We then show how this measure can be used with each of a one-class SVM, a nearest neighbor classifier, and hierarchical clustering to improve risk stratification. We evaluated our methods on a population of 686 cardiac patients with available long-term electrocardiographic data. In a univariate analysis, all of the methods provided a statistically significant association with the occurrence of a major adverse cardiac event in the next 90 days. In a multivariate analysis that incorporated the most widely used clinical risk variables, the nearest neighbor and hierarchical clustering approaches were able to statistically significantly distinguish patients with a roughly two-fold risk of suffering a major adverse cardiac event in the next 90 days.
关 键 词: 心血管疾病; 无监督机器学习方法; 心脏危险分层
课程来源: 视频讲座网
最后编审: 2019-07-26:cwx
阅读次数: 39