Abstract P157: Tractography of White Matter Connections Predicts for Vascular Cognitive Impairment in Hypertensive Patients

Abstract

Vascular cognitive impairment (VCI) results by several vascular risk factors and, particularly, hypertension (HTN). The identification of early changes associated with later development of dementia is demanding. Great part of research has primarily focused on brain changes occuring in grey matter. However, more recent data highlighted that HTN may determine cognitive decline, even before manifest neurodegeneration. Diffusion tensor imaging (DTI) on magnetic resonance, opened the possibility to predict white matter connections that correlate with specific cognitive functions. In this study, we used DTI and cognitive assessment (CA), in order to identify a regional pattern of fractional anisotropy (FA) changes that could predict for VCI in hypertensive patients (HT). We have examined 15 HT (moderate to severe, with antihypertensive medications) vs 15 normotensive (NT), subjecting them to DTI and CA. HT had significant higher SBP (138±4 vs 118±3 in NT) and DBP (87±2 vs 75±2 in NT) (p<0.001), displayed a significant LV hypertrophic remodeling (LVM/BSA 112±5 vs 83±3 for NT) (p<0.0001), with a significant moderate increase in albuminuria (15.7±2.6 mg/24h vs 8.8±1.6 for NT) (p<0.03). When subjected to CA, HT had significantly worsen performance on both MoCA (22.66±0.97 vs 26.21±0.57 NT) and Stroop Test (34.50±3.87 vs 17.75±2.57 NT) (p<0.01). Conversely, tests regarding Verbal Fluency and Instrumental Activities of Daily Living revealed normal performance of HT, thus indicating a selective impairment of memory. Brain imaging showed that, while none of the patients had abnormal signal intensity on T1/T2-weighted MRI, DTI indices FA were significantly reduced in HT as vs NT. In particular, HT had lower FA in projection fibers related to impairment for non-verbal materials (Anterior Thalamic Radiation: 0.358±0.012 vs 0.330±0.006, p<0.05), association fibers involved in executive functioning and emotional regulation (Superior Longitudinal Fasciculus: 0.388±0.013 vs 0.356±0.007, p<0.05), limbic system fibers involved in attention tasks (cingulate gyrus: 0.364±0.009 vs 0.328±0.010, p<0.01). Our data highlight a novel paradigm of combined DTI/CA of HT patients, capable to identify, with great sensitivity, predictive signs of HTN-induced VCI.