LAUSR

Background and Objectives: Acute small subcortical infarcts (SSI) result in high rates of early neurological deterioration (END) despite best medical management. Those with SSI-related END have worse functional outcomes after stroke leading to increased morbidity. Presently, it is unknown in a robust manner the incidence or risk factors for END within this demographic. The aim of this study was to perform a systematic review and meta-analysis to understand the incidence and risk factors of SSI-related END. Methods: We searched PubMed, Cochrane Library, and Google Scholar between January 1, 2000, and June 1, 2022, including both retrospective cross-sectional and prospective observational studies. The primary outcome was development of END based on publishing authors’ definition. Abstracted data included age, sex, cohort size, diagnoses of hypertension, hyperlipidemia, diabetes mellitus, study definition of END and SSI, and presence of branch atheromatous disease (BAD) and lesion diameter. Results: We identified 31 studies enrolling 6376 patients. Most studies were conducted in East Asia (27/31, 87%) and had a least some concern for risk of bias. Funnel plot illustrated a high level of publication bias favoring high incidence studies. END was commonly defined as ≥ 2 overall NIHSS change or ≥ 1 motor change within 3 to 7 days from admission (average: 5 days). A pooled proportion of END was 22% (95%CI 0.19 - 0.25, I2 = 91.2%, 31 studies). Meta-regression identified that female sex [risk ratio (RR) 1.23, 95%CI 1.09-1.39, I2=30.8%, 31 studies], diabetes mellitus (RR 1.16 95%CI 1.01-1.33, I2=38.4%, 30 studies), and BAD (RR 1.99 95%CI 1.61-2.46, I2=50.7%, 17 studies) as risk factors for END. Discussion: Our data identified primarily within an East Asian cohort that risk factors for SSI-related END include diabetes mellitus and branch atheromatous disease with a pooled prevalence of END occurring in 1 in 4 patients. Future studies are needed to understand treatment and preventative strategies for this patient population.