Impact of white matter hyperintensities on the prognosis of cryptogenic stroke patients

Background
To our knowledge, little is known regarding whether white matter hyperintensities (WMH) affect the prognosis of cryptogenic stroke (CS) patients. Understanding this association may be helpful with expecting the prognosis of CS patients.
Methods
This retrospective observational study enrolled consecutive CS patients who underwent brain MRI and comprehensive cardiac evaluation. Severe WMH was defined as Fazekas’ score ≥3. We defined poor functional outcome as modified Rankin Scale score ≥3 at 3 months. Long-term mortality and causes of death were identified using national death certificates and assessed by Kaplan-Meier method and regression analysis model.
Results
Among 2732 patients with first-ever ischemic stroke, 599 (21.9%) patients were classified as having CS. After exclusions, 235 patients were enrolled and followed up for a median of 7.7 years (IQR, 6.7–9.0). Severe WMH were found in 81 (34.5%) patients. After adjustments, severe WMH were an independent predictor for poor functional outcomes at 3 months (OR 5.25, 95% CI, 2.07–13.31). Subgroup analysis showed that severe WMH were an independent predictor for long-term mortality only in younger patients (age < 65) (HR 3.11, 95% CI, 1.29–7.50), but not in older patients (HR 1.19, 95% CI, 0.63–2.23).
Conclusions
Severe WMH were independently associated with short-term functional outcomes in CS patients and independently associated with long-term mortality in younger CS patients. Grading WMH is of value in predicting prognosis of CS patients with young age.

背景
据我们所知，目前关于脑白质高信号（white matter hyperintensities, WMH）是否会影响隐源性卒中（cryptogenic stroke, CS）患者的预后，相关研究尚少。明确二者间的关联，或有助于预判隐源性卒中患者的预后。

方法
本项回顾性观察研究纳入了连续收治的隐源性卒中患者，所有受试者均接受了颅脑MRI检查与全面心脏评估。本研究将重度脑白质高信号定义为Fazekas评分≥3分；将3个月时改良Rankin量表评分≥3分定义为不良功能结局。通过国家死亡证明书确定受试者的长期死亡率与死亡原因，并采用Kaplan-Meier法与回归分析模型进行评估。

结果
在2732例首发缺血性卒中患者中，共有599例（21.9%）被归类为隐源性卒中患者。经排除后，最终纳入235例患者，中位随访时间为7.7年（四分位间距：6.7~9.0年）。其中81例（34.5%）患者存在重度脑白质高信号。经校正后，重度脑白质高信号是3个月时不良功能结局的独立预测因素（优势比OR=5.25，95%置信区间CI：2.07~13.31）。亚组分析显示，重度脑白质高信号仅在年龄<65岁的年轻患者中，是长期死亡率的独立预测因素（风险比HR=3.11，95%CI：1.29~7.50），而在老年患者中无此关联（HR=1.19，95%CI：0.63~2.23）。

结论
重度脑白质高信号与隐源性卒中患者的短期功能结局独立相关，同时在年轻隐源性卒中患者中，其与长期死亡率亦存在独立关联。对脑白质高信号进行分级，有助于预判年轻隐源性卒中患者的预后。