Vascular cognitive impairment and dementia (VCID), ie, cognitive impairment secondary to cerebrovascular disease (CeVD), is the second most common form of dementia after Alzheimer's disease (AD), accounting for 15% to 20% of all cases. CeVD, in fact, contributes to dementia alongside other neuropathologies in up to 75% of dementia cases. CeVD and AD not only frequently co-occur in the brain, but they may also interact, and some VCID risk factors (midlife hypertension and diabetes) also increase AD risk. Because CeVD and cardiovascular disease share risk factors and pathophysiology, the cardiovascular clinician is likely to encounter both in the clinic. Moreover, common cardiac disorders, such as atrial fibrillation, heart failure, acute coronary syndrome, and valvular disease, increase VCID risk. There have been recent developments in the diagnostic criteria for VCID, with advances in risk biomarkers, treatment, and prevention of cognitive impairment and dementia. The diagnosis of VCID is a 2-step process, with the initial identification of a cognitive syndrome followed by the establishment of a predominantly vascular etiology, guided by clinical history and examination and substantiated by neuroimaging, preferably magnetic resonance imaging. Clinical presentations include an acute onset, a stepwise decline, a fluctuating course if caused by multiple strokes, or a gradual slow progression if attributable to cerebral small vessel disease. Cognitive deficits can be found in several domains, such as information-processing speed, attention, executive function, and emotional lability, sometimes referred to as the subcortical syndrome, often seen in the early stages of VCID without cortical infarcts. The diagnosis is supported by the identification of large and small infarcts, lacunes, white matter hyperintensities, dilated perivascular spaces and cerebral microbleeds using magnetic resonance imaging. This part 1 of a 2-part JACC review series describes the clinical features, pathophysiology, and biomarkers of VCID for cardiovascular clinicians who have a critical role in its early identification, management, and prevention in their patients.
