Abstract 23: Predictors of Early Neurological Deterioration in the Single Small Subcortical Infarctions

Background: Early neurological deterioration (END) occurs in ≥20% of single small subcortical infarctions (SSSIs; axial diameter ≤20 mm in the perforator territories) and deters functional recovery. SSSIs are supposed to have two distinct pathological processes including microvasculopathies of arteriolar walls and the localized atherosclerosis of the upstream arteries. We hypothesized that the occurrence of END in the SSSIs differs according to the pathological processes. Methods: From a total of 4961 stroke cases between July 2007 and July 2013, we assessed 587 patients with SSSI within 48 hours of onset. END was assessed prospectively as a quality improvement program of stroke care. Functional outcomes after stroke were also collected prospectively by telephone or face-to-face interview. Independent reviewers rated neuroimaging characteristics with the acceptable inter-rater reliability including relevant artery stenosis (0 - 50% stenosis of the adjacent arteries on MR angiography), branched atheromatous lesion (≥4 consecutive axial cuts or extension from the basal surface of brainstem), white matter hyperintensities, old lacunar infarction and cerebral microbleeds. Results: END occurred in 79 (13.5%) cases, including 6 recurrences (8%), 66 progressions (84%) and 7 other causes (9%). Symptomatic hemorrhagic transformation was not documented. NIHSS score was increased when END occurred by 2.3 ± 1.4 points. END patients had higher frequency of having mRS score 3 - 6 at 3 months than those without END (49% vs. 23%). In the multivariable analyses, relevant artery stenosis (adjusted OR 1.91, 95% CI 1.13 - 3.21) and branch atheromatous lesion (2.98; 1.80 - 4.93) had significantly higher odds of having END. However, such association was not detected in the stigmas of small vessel diseases. Conclusions: Relevant artery stenosis and branch atheromatous lesions were significantly associated with the occurrence of END in SSSIs, which suggest a potential contribution of the localized atherosclerotic process to the END in SSSIs. Our results suggest that precautionary measures might be utilized for SSSI patients with higher atherosclerotic burdens.