Cognitive functioning and chronic heart failure: a review of the literature (2002-July 2007).

PURPOSE: The purposes of this article are to (1) summarize the state of the science about cognitive impairment and heart failure (HF) using the results of a literature search of publications from 2002 through July 2007; (2) provide a focused review of the studies that used a prospective, longitudinal design with measurement at 2 or more time points in order to identify change in cognitive functioning; and (3) identify gaps and priorities for future studies.
METHODS: A computer search of the literature from 2002 through July 2007 was conducted. All of the resulting 97 references were reviewed, categorized into 8 groups, and evaluated.
RESULTS: The 97 studies were categorized as follows: those not directly related to cognitive impairment (n = 15); comments, letters to the editor, and brief summaries (n = 11); reviews (n = 15); data-based publications using screening measures (n = 14); data-based publications using neuropsychological tests (n = 10); data-based publications assessing brain structure and functioning (n = 22); and data-based publications of populations other than HF in which HF emerged as a correlate/predictor of cognitive impairment (n = 10). Many investigators have reported that patients with HF had cognitive impairments compared with healthy persons without HF; approximately 25% to 50% of HF patients experience cognitive impairments. Patients with HF have been found to have structural and functional brain changes, including losses in gray matter in specific areas, areas of silent stroke, and decreased cerebral perfusion. Gaps in our knowledge and future research priorities are proposed.
CONCLUSIONS: Future studies are urgently needed to identify mechanisms of cognitive impairment in HF, prospectively identify changes in cognitive functioning that occur over time, and evaluate screening measures for use in clinical settings.