The brain is an intricately vascular target organ of the circulatory system, receiving approximately 15% of the heart’s cardiac output – a significant proportion considering it accounts for only 2% of human body weight (Sokoloff, 1997). When cardiovascular health is compromised either acutely or chronically, brain health and neurocognition can be threatened as well. The impact of clinical cardiovascular diseases on brain structure and function has been studied extensively, with documented associations between multiple diseases (e.g., coronary artery disease, hypertension) and neurocognitive function (Waldstein, Wendell, Hosey, Seliger, & Katzel, 2010). An emerging literature suggests that subclinical cardiovascular diseases may also lead to decrements in neurocognitive function. Subclinical cardiovascular diseases – including atherosclerosis, arterial stiffness, endothelial dysfunction, and left ventricular dysfunction – represent presymptomatic, or “preclinical” cardiovascular disease states. They are considered the earliest forms of cardiovascular disease that occur without overt symptom manifestation. Importantly, subclinical cardiovascular diseases can confer as much, or possibly more, substantive risk for future clinical events (e.g., myocardioal infarction, stroke) than the presence of traditional cardiovascular risk factors. There is currently no specific, documented consensus regarding accurate categorization of diseases as “subclinical” vs. “clinical.” However, guidance regarding the most widely accepted and studied subclinical cardiovascular diseases can be gleaned from Table 11.1, which lists Cardiovascular Health Study criteria, as well as two seminal review articles. Nevertheless, this table suggests remarkable heterogeneity in the classification of subclinical cardiovascular diseases. The incidence and prevalence of subclinical cardiovascular diseases is challenging to ascertain, by virtue of their lack of manifest symptoms. Nevertheless,

several population-based studies have attempted to shed light on their prevalence. As an example, among a sample of 5,201 older adult (r65 years old) Cardiovascular Health Study participants derived from four representative U.S. communities, overall prevalence of subclinical cardiovascular disease was 36% for women and 38.7% for men (Kuller et al., 1994). Of the subclinical cardiovascular diseases studied (see Table 11.1), indicators of carotid artery disease were generally the most prevalent, accounting for approximately 25-50% of all subclinical diseases, depending upon gender and marker used. Analyses also demonstrated increased prevalence of subclinical disease with age. In the following sections, we first provide a multi-level, in-depth rationale for the importance of studying subclinical diseases. Next, we review each of the major subclinical cardiovascular disease states, including their pathophysiology, measurement (see Table 11.2), and associations with neurocognitive function and dementia outcomes. Following this review, we comment on possible pathophysiological mechanisms, clinical significance, and potential impact on daily function and quality of life. We then conclude with a discussion of existing intervention research as well as recommendations for future research examining neurocognitive function and subclinical cardiovascular disease states.