BACKGROUND Stroke is a leading cause of death and disability worldwide. Identifying the aetiology of ischaemic stroke is essential in order to initiate appropriate and timely secondary prevention measures to reduce the risk of recurrence. For the majority of ischaemic strokes, the aetiology can be readily identified, but in at least 30% of cases, the exact aetiology cannot be determined using existing investigative protocols. Such strokes are classed as 'cryptogenic' or as a stroke of unknown origin. However, there exists substantial variation in clinical practice when investigating cases of seemingly cryptogenic stroke, often reflecting local service availability and the preferences of treating clinicians. This variation in practice is compounded by the lack of international consensus as to the optimum level and timing of investigations required following a stroke. To address this gap, we aim to systematically review and compare recommendations in evidence-based clinical practice guidelines (CPGs) that relate to the assessment and investigation of the aetiology of ischaemic stroke, and any subsequent diagnosis of cryptogenic stroke. METHOD We will search for CPGs using electronic databases (MEDLINE, Health Management Information Consortium (HMIC), EMBASE, and CINAHL), relevant websites and search engines (e.g. guideline specific websites, governmental, charitable, and professional practice organisations) and hand-searching of bibliographies and reference lists. Two reviewers will independently screen titles, abstracts and CPGs using a pre-defined relevance criteria form. From each included CPG, we will extract definitions and terms for cryptogenic stroke; recommendations related to assessment and investigation of the aetiology of stroke, including the grade of recommendations and underpinning evidence. The quality of the included CPGs will be assessed using the AGREE II (Appraisal of Guidelines for Research and Evaluation) tool. Recommendations across the CPGs will be summarised descriptively highlighting areas of convergence and divergence between CPGs. DISCUSSION To our knowledge, this will be the first review to systematically compare recommendations of international CPGs on investigating the aetiology of ischaemic stroke. The findings will allow for a better understanding of international perspectives on the optimum level of investigations required following a stroke and thus contribute to achieving greater international consensus on best practice in this important and complex area. SYSTEMATIC REVIEW REGISTRATION PROSPERO CRD42019127822.

中文翻译：

---

隐源性中风病例的病因学检查：国际临床实践指南的系统回顾和比较方案。

背景技术中风是全世界死亡和残疾的主要原因。确定缺血性中风的病因对于及时采取适当的二级预防措施以降低复发风险至关重要。对于大多数缺血性中风，可以很容易地确定病因，但在至少 30% 的病例中，使用现有的研究方案无法确定确切的病因。此类中风被归类为“隐源性”或不明原因中风。然而，在调查看似不明原因的中风病例时，临床实践存在很大差异，通常反映了当地服务的可用性和治疗临床医生的偏好。由于中风后所需调查的最佳水平和时间缺乏国际共识，加剧了实践中的这种差异。为了解决这一差距，我们的目标是系统地回顾和比较循证临床实践指南（CPG）中与缺血性中风病因评估和调查以及隐源性中风任何后续诊断相关的建议。方法 我们将使用电子数据库（MEDLINE、健康管理信息联盟 (HMIC)、EMBASE 和 CINAHL）、相关网站和搜索引擎（例如指南特定网站、政府、慈善和专业实践组织）以及手动搜索来搜索 CPG参考书目和参考文献列表。两名审稿人将使用预定义的相关性标准表格独立筛选标题、摘要和 CPG。从每个包含的 CPG 中，我们将提取隐源性中风的定义和术语；与中风病因评估和调查相关的建议，包括建议的等级和基础证据。所包含的 CPG 的质量将使用 AGREE II（研究和评估指南评估）工具进行评估。将对 CPG 的建议进行描述性总结，突出 CPG 之间的趋同和分歧领域。讨论 据我们所知，这将是第一次系统比较国际 CPG 关于调查缺血性卒中病因的建议的综述。研究结果将使人们更好地了解中风后所需调查的最佳水平的国际观点，从而有助于就这一重要而复杂领域的最佳实践达成更大的国际共识。系统审查注册 PROSPERO CRD42019127822。