Can smaller lacunes derived from recent small subcortical infarcts play a role in cognition at one- year after mild stroke?

Introduction

Recent small subcortical infarcts (RSSI) may evolve into lacunes (cavities) smaller than 3mm or even disappear. The 3mm size cut-off used in guidelines might underestimate SVD burden. We hypothesised that participants with smaller (<3mm) lacunes have better cognitive outcomes at one-year follow-up than those with larger lacunes. We also aimed to determine rates of development of lacunes <3mm.

Methods

We recruited participants from two prospective stroke cohorts (MSS2 and MSS3) within 3-months after mild stroke. We included participants with MRI-confirmed RSSI and at least two MRI scans during the first one-year follow-up. We assessed for lesion change by visual assessment on T2- FLAIR (blinded). We recorded demographics, vascular risk factors, SVD burden, and clinical outcomes (NIHSS, modified Rankin score [mRS], Montreal Cognitive Assessment score [MoCA]), at baseline and one-year. We report maximum axial diameters (max-ax, mm) for RSSI and lacunes (continuous and dichotomised at < /≥3mm). We used regression analysis for associations between final lacune size/appearance and outcomes at one-year, adjusting for baseline demographics, VRF, and clinical scores.

Results

We included 198 participants; mean age 64 years (SD 11.1); 33% female. At one-year, 53/184 (26.8%) RSSI evolved into lacunes <3mm and 105/184 in to lacunes over 3mm (Table.1) Participants with lacunes <3mm had higher MoCA (MoCA<26; RR=0.57 [95%CI 0.33, 0.97]; vs 1.35 [1.05-1.75] for larger lacunes; p=0.03) and lower mRS (mRS 0-1; RR=1.79[1.11,2.91] vs 0.72[0.58-0.89]; p=.009). The end-stage lacune size correlated with RSSI max-ax diameter at baseline (r[df1]=[0.73],p<.001); there were no associations with demographics, VRF or SVD burden. At one-year, 47/143 (23.7%) participants had MoCA<26, and we investigated the effects of age, NIHSS, NART, RSSI max-ax diameter, SVD burden and MoCA at baseline and end-stage lacune max-axial diameter in this group. MoCA at baseline was a significant predictor for cognition at one-year (β=0.586, SE=0.90 [95%CI: 0.41, 0.76], p<.001). MoCA scores were lower in those with larger end-stage lacunes (β=-1.950, SE=0.70 [95%CI: 0.04, 0.56], p=0.005).

Discussion

Larger end-stage lacune diameters are associated with worse cognitive outcomes at one-year after mild stroke. Careful cognitive and lesion assessment of patients at diagnosis may help determine cognitive trajectories in patients with mild stroke.