Effects of small vessel disease on post-stroke clinical outcomes

Abstract

Background: The influence of cerebral structural abnormality on stroke rehabilitation outcome is unclear. This study examined the prevalence and clinical impact of white matter hyperintensities (WMH), cerebral microbleeds (CMB) and medial temporal lobe atrophy (MTLA) on short and long term outcome after stroke rehabilitation. Methods: We analysed the data for 377 consecutive patients with confirmed stroke admitted to the stroke rehabilitation unit at Tung Wah Hospital between 1 March 2008 and 23 May 2014. 3T MRI brain images were retrospectively examined for the severity and location of WMH (Fazekas Score 0-3, >1 abnormal), CMB (Microbleed Anatomical Rating Scale 0-3, >5 abnormal) and MTLA (Scheltens Score 0-4, >1 abnormal). Stroke rehabilitation outcomes were assessed by comparing functional status between admission and discharge. For 208 patients who were admitted between March 2008 and May 2012, we also retrieved data on clinical outcomes (death or any vascular events, post-stroke dementia) at 2 years. Results: Mean (± s.d.) age was 70 ± 12 years. 94% were ischaemic strokes, and the overall stroke severity was mild to moderate according to the baseline functional scores. 12.6% of the patients had abnormal periventricular WMH, 48% had abnormal subcortical WMH, 11% had CMB, and up to 36% had abnormal MTLA. Stroke subtypes and functional status on admission, all four MRI abnormalities, independently predicted functional improvement (balance, mobility, functional level and independence) during stroke rehabilitation. At 2 years follow-up, 11% had died or any vascular events. Periventricular WMH, CMB and MTLA predicted 2-year clinical outcomes. However, after adjusting for case mix, only MTLA independently predicted pneumonia [OR 0.17 (0.05-0.56)], and periventricular WMH independently predicted falls [OR 5.0 (1.5-16.88)] at 2 years. Conclusion: MRI biomarkers of small vessel disease burden and medical temporal lobe atrophy are prevalent amongst patients undergoing stroke rehabilitation, and they may independently predict short and longer term outcomes after stroke. The role of MRI in improving the prediction of short and long term outcome after stroke rehabilitation warrants further research.