Development of a Molecular Diagnostic to Identify Dangerous Intracranial Aneurysms

项目摘要 颅内动脉瘤（IA）破裂是非创伤性蛛网膜下腔出血的主要原因， 具有高死亡率（>50%）和永久性残疾（幸存者中>50%）的灾难性事件。 当发现未破裂的IA时，临床医生面临是否应该治疗的困难决定。 由于破裂率较低（每年破裂风险约为0.5-1%），而干预的并发症风险可能较低， 重要的是，对破裂风险进行分层至关重要，以便立即处理危险的IA， 危险的可以定期监测。在临床实践中，动脉瘤大小一直是主要标准 但并不总是可靠的。最近，其他临床指标，如PHASES（人口， 高血压、年龄、颅内动脉瘤大小、早期蛛网膜下腔出血和颅内动脉瘤部位）评分 已经开发并验证了患者特征和患者人口统计学，以尝试更好地对风险进行分层。 然而，与IA大小一样，只有在患者接受数字化治疗后，才能准确评估此类风险指标。 减影血管造影术（DSA），这是侵入性的，昂贵的（每次扫描5000 - 8500美元），并有风险的短暂或 永久性并发症此外，这些指标缺乏关于潜在的生物学差异的信息， 可以更好地区分高风险与低风险病例的IA。危险颅内动脉瘤的血液诊断 实现更明智的IA管理，并可提供低成本、非侵入性的方式来监测患者 观察等待期间或治疗后（随访成像之间）。 在过去的几年里，Neurovascular Diagnostics一直在开发一种基于血液的IA诊断方法， 称为AneuScreenTM。在发育过程中，我们发现某些基因的表达差异也分层 IA病例以“剂量依赖性”方式按IA大小分类，导致我们假设高风险IA患者 在他们的血液中有不同的基因表达模式。在一个成功完成的SBIR第一阶段项目中， 我们使用来自IA患者的中等规模数据集的全血转录组来开发和测试机器， 学习高风险动脉瘤病例的分类器（由PHASES评分描述）。这个模型有88%的测试 准确性78%，特异性95%。尽管有这些令人兴奋的结果，但还需要进一步的工作来翻译 将这种生物标志物转化为诊断测试，这是第二阶段SBIR项目的重点。在目标1中，我们将验证 IA风险生物标志物内的基因在先前收集的血液样本的大数据集中， 进行RNA测序。在目标2中，我们将标准化生物标志物的评估， 该临床平台利用qPCR和毛细管电泳进行表达读出。模型将重新- 经过训练，可以很好地使用这种新的输出数据类型。最后，在目标3中，我们将测试所开发的测定法， 我们称之为AneuScreenTM+（或AneuScreenTM Plus），在一个前瞻性队列中，n=400例IA患者和n=200例 对照第二阶段的成功完成将决定我们的原型IA诊断是否可以扩展其 能力，并通过对IA风险进行分层来增加其价值。

Project Summary Intracranial aneurysm (IA) rupture is the primary cause of non-traumatic subarachnoid hemorrhage, a catastrophic event that carries high rates of mortality (>50%) and permanent disability (>50% among survivors). When an unruptured IA is discovered, clinicians face the difficult decision of whether or not it should be treated. Since rupture rates are low (risk of rupture ~ 0.5-1% per year), while complication risks of intervention can be significant, it is critical to stratify rupture risk such that the dangerous IAs are treated right away while less dangerous ones can be periodically monitored. In clinical practice, aneurysm size has been the principal criterion for treatment, but it is not always reliable. Recently, other clinical metrics, such as the PHASES (Population, Hypertension, Age, Size of IA, Earlier subarachnoid hemorrhage, and Site of IA) score, which use IA characteristics and patient demographics, have been developed and validated in attempts to better stratify risk. However, like IA size, such risk metrics can only be accurately assessed after the patient has received digital subtraction angiography (DSA), which is invasive, expensive ($5,000-8,500 per scan), and risky for transient or permanent complications. Furthermore, these metrics lack information about biological differences underlying IAs that may better discriminate high- vs low-risk cases. A blood-based diagnostic of dangerous IAs would enable more informed IA management and could offer a low-cost, non-invasive way to monitor patients during watchful waiting or after treatment (between follow-up imaging). Over the past several years, Neurovascular Diagnostics has been developing a blood-based IA diagnostic called AneuScreenTM. During development, we found that expression differences of certain genes also stratified IA cases by IA size in a “dose-dependent” manner, leading us to hypothesize that patients with high-risk IAs have distinguishable gene expression patterns in their blood. In a successfully completed Phase I SBIR project, we used whole blood transcriptomes from a modestly-sized dataset of IA patients to develop and test machine learning classifiers of high-risk aneurysm cases (delineated by PHASES score). This model had 88% testing accuracy, 78% sensitivity, and 95% specificity. Despite these exciting results, further work is needed to translate this biomarker into a diagnostic test, which is the focus of this Phase II SBIR project. In Aim 1, we will validate the genes within the IA risk biomarker in a large dataset of previously-collected blood samples that will be subjected to RNA sequencing. In Aim 2, we will standardize the assessment of the biomarker on an established clinical platform that utilizes qPCR and capillary electrophoresis for expression readout. The models will be re- trained to perform well using this new output data-type. Lastly, in Aim 3, we will test the developed assay, which we call AneuScreenTM+(or AneuScreenTM Plus), in a prospective cohort of n=400 patients with IA and n=200 controls. Successful completion of this Phase II will determine if our prototype IA diagnostic can expand its capabilities and increase its value by stratifying IA risk, in addition to identifying IA.