White matter hyperintensities, cerebral microbleeds, and medial temporal lobe atrophy in high-risk non-demented adults: prevalence and progression over 2 years

Abstract

Background: MRI markers of small vessel disease [white matter hyperintensities (WMH) and cerebral microbleeds (CMB)] and medial temporal lobe atrophy (MTLA) are frequent findings in patients with stroke and dementia. This was a hospital-based study to examine the prevalence of these MRI abnormalities amongst high-risk non-demented adults, and the risk factors for progression over 2 years. Methods: We analysed the data for 29 older non-demented adults (mean ± s.d. age was 73.8 ± 8.5 years, 66% male) with high baseline vascular risk. Each patient had undergone two brain MRI scans with a mean interval of 2 ± 0.9 years. 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, >0 abnormal) and MTLA (Scheltens Score 0-4, >1 abnormal). Comparisons were made between the first and second MRI for each patient. Results: Amongst our 29 participants, 38% were current/ex-smokers, 83% had hypertension, 35% had diabetes mellitus, 21% had coronary heart disease, 65% had previous stroke, 62% had hyperlipidaemia, and 7% had atrial fibrillation (AF). For medications, 35% were on statins, 69% on antiplatelet agents, and 10% on oral anticoagulants. MRI at baseline showed that 100% had subcortical WMH, 83% had periventricular WMH, 57% had CMB, and 38% had MTLA. During a mean interval of 2 years, 33% had progression of WMH, 32% had higher numbers of CMB (16% had worse CMB grades), and 38% had progression of MTLA. Patients with AF were more likely to experience WMH progression (p=.038), and patients with diabetes were more likely to experience MTLA progression (p=.01). Age, other vascular risk factors and prior antithrombotics and statin use were not significantly correlated with progression of MRI abnormalities. Multiple logistic regression analyses found no independent predictive factors. Conclusion: Amongst older non-demented adults with high cardiovascular risk, MRI markers of small vessel disease and MTLA are highly prevalent. One-in-three patients demonstrate rapid progression in WMH, CMB and MTLA within 2 years. AF and diabetes may exacerbate cerebral aging and progressive vascular damage, but their independent risks are unclear. Future trials should examine the effectiveness of vascular preventive interventions (e.g. use of non-vitamin K anticoagulants for AF) on cerebral protection.