The AHA/ASA & DSM-V diagnostic criteria for vascular cognitive impairment identify cases with predominant vascular pathology.

BACKGROUND:There are major challenges in determining the aetiology of vascular cognitive impairment (VCI) clinically, especially in the presence of mixed pathologies, such as vascular and amyloid. Most recently, two criteria (American Heart Association/American Stroke Association [AHA/ASA] and Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition [DSM-V]) have been proposed for the clinical diagnosis of VCI but have not as yet been validated using neuroimaging.AIMS:This study aims to determine whether the AHA/ASA and DSM-V criteria for VCI can distinguish between cases with predominantly vascular pathology and cases with mixed pathology.METHODS:186 subjects were recruited from a cross-sectional memory clinic-based study at the National University Hospital, Singapore. All subjects underwent clinical and neuropsychological assessment, MRI and [11C] PiB PET scans. Diagnosis of the etiological subtypes of VCI [probable vascular mild cognitive impairment (VaMCI), possible VaMCI, non-VaMCI, probable vascular dementia (VaD), possible VaD, non-VaD] were performed following AHA/ASA and DSM-V criteria. Brain amyloid burden was determined for each subject with standardised uptake value ratio (SUVR) values ≥ 1.5 classified as amyloid positive.RESULTS:Using κ statistics, both criteria had excellent agreement for probable VaMCI, probable VaD, and possible VaD (κ=1.00), and good for possible VaMCI (κ=0.71). Using the AHA/ASA criteria, the amyloid positivity of probable VaMCI (3.8%) and probable VaD (15%) was significantly lower compared to possible VaMCI (26.7%), non-VaMCI (33.3%), possible VaD (73.3%) and non-VaD (76.2%) )(p<0.001). Similarly, using the DSM-V criteria the amyloid positivity of probable VaMCI (3.8%) and probable VaD (15%) were significantly lower compared to possible VaMCI (26.3%), non-VaMCI (32.1%), possible VaD (73.3%) and non-VaD (76.2%)(p<0.001). In both criteria, there was good agreement in differentiating individuals with non-VaD and possible VaD, with significantly higher (p<0.001) global [11C]-PiB SUVR, from individuals with probable VaMCI and probable VaD, who had predominant vascular pathology.CONCLUSIONS:The AHA/ASA and DSM-V criteria for VCI can identify VCI cases with little to no concomitant amyloid pathology, hence supporting the utility of AHA/ASA and DSM-V criteria in diagnosing patients with predominant vascular pathology.