Special Article
Relationship between Cognitive Impairment and Echocardiographic Parameters: A Review

https://doi.org/10.1016/j.echo.2014.11.009Get rights and content

With >24 million people affected worldwide, dementia is one of the main public health challenges modern medicine has to face. The path leading to dementia is often long, with a wide spectrum of clinical presentations, and preceded by a long preclinical phase. Previous studies have demonstrated that clinical strokes and covert vascular lesions of the brain contribute to the risk for developing dementia. Although it is not yet known whether preventing such lesions reduces the risk for dementia, it is likely that starting preventive measures early in the course of the disease may be beneficial. Echocardiography is a widely available, relatively inexpensive, noninvasive imaging modality whereby morphologically or hemodynamically derived parameters may be integrated easily into a risk assessment model for dementia. The aim of this review is to analyze the information that has accumulated over the past two decades on the prognostic value of echocardiographic factors in cognitive impairment. The associations between cognitive impairment and echocardiographic parameters, including left ventricular systolic and diastolic indices, left atrial morphologic parameters, cardiac output, left ventricular mass, and aortic root diameter, have previously been reported. In the light of these studies, it appears that echocardiography may help further improve currently used risk assessment models by allowing detection of subclinical cardiac abnormalities associated with future cognitive impairment. However, many limitations, including methodologic heterogeneity and the observational designs of these studies, restrict the scope of these results. Further prospective studies are required before integrating echocardiography into a preventive strategy.

Section snippets

Clinical Determinants of Cognitive Impairment

The main clinical factors associated with cognitive impairment are advanced age, hypertension, diabetes mellitus, high plasma cholesterol levels, obesity, tobacco smoking, and the presence of atherosclerotic vascular disease.9, 10, 11, 12, 13, 14 In addition to these risk factors, hyperhomocysteinemia, diets comprising high levels of saturated fats, excessive alcohol consumption, and physical inactivity increase the risk for developing Alzheimer's disease.15 These risk factors are also

Cognitive Impairment Risk Evaluation Models

It is now accepted that a preclinical phase exists in dementia, hence the early identification of patients at risk for developing the disease is likely to be a key step.2 In 2006, Kivipelto et al.26 proposed a cognitive impairment risk evaluation model, the Cardiovascular Risk Factors, Aging and Dementia risk score, to predict the 20-year risk for dementia in middle-aged people. This model stratifies patients by age, sex, education, hypertension, body weight, physical activity, hyperlipidemia,

Conventional Echocardiographic Parameters of the Left Ventricle and Cognitive Impairment

The presence of a heart disease may alter left ventricular (LV) function, leading to a reduction in cerebrovascular blood flow causing subclinical brain injury and cognitive impairment.42, 43, 44, 45 It was described previously that patients with severe chronic heart failure may have reduced cerebral blood flow, by approximately 30%, despite the activation of physiologic neurohormonal counterregulatory mechanisms such as the renin-angiotensin system and the sympathetic nervous system.46

Left Atrial Enlargement Parameters and Cognitive Impairment

Left atrial (LA) function can be considered as a three-component model.66 The first component occurs during LV systole and is called the reservoir phase, in which the left atrium receives blood from the pulmonary veins. The second component is called the passive conduit phase, occurring during LV early diastole and diastasis. The LA contraction phase is the third component, in which the left atrium acts as a contractile pump during late diastole LV filling, contributing to the increase in LV

Cardiac Output and Cognitive Impairment

The exact mechanism governing the link between cognitive impairment and reduced CO remains unknown.43, 67, 81 It has previously been reported that counterregulatory mechanisms contribute to the increase of cerebral blood flow during acute periods of reduced CO.82 However, chronic CO reduction may decrease cerebral blood flow, overwhelming autoregulatory phenomena and leading to brain injury, particularly in elderly individuals with hypertension, in whom a shift of the cerebral autoregulation

Left Ventricular Mass and Cognitive Impairment

The main hypothesis linking cognitive impairment to increased LV mass is the fact that LV mass may be a reflection of chronic exposure to high blood pressure, a recognized risk factor for dementia.91, 92 Table 4 details the main studies that investigated the link between LV mass and cognitive impairment. Scuteri et al.92 found that an increased LV mass index was associated with cognitive impairment and a higher probability of developing dementia independently of blood pressure in a population

Aortic Root Diameter and Cognitive Impairment

Paul et al.51 found that an increased aortic root diameter was associated with both impaired cognitive function and cerebral abnormalities on brain MRI, including white matter lesions and whole-brain volume. The relationship between ischemic brain infarction and aortic arch morphology has been described previously.96, 97, 98, 99, 100 This link may be explained by the fact that dilation of the aorta has been associated with the presence of atherosclerotic plaques in the vessel, which are known

Epicardial Fat Thickness and Cognitive Impairment

Recently, a growing amount of interest has been focused on the link between the amount of visceral adiposity and cognition.102 The epicardial adipose tissue is a recognized index of visceral adiposity,103 a marker of cardiovascular risk,104 and has been associated with inflammation modulators that may play a role in coronary atherosclerosis and in vasculopathic effects mediated by systemic inflammation.105 Considering that chronic inflammation is associated with systemic vasculopathy and

Is There Enough Evidence to Integrate Echocardiography Into a Preventive Strategy?

In this review, we found strong evidence in favor of the existence of an association between echocardiographic parameters and cognitive impairment. One of the most interesting, but arduous, questions that subsequently arises focuses on the nature of the underlying mechanisms governing this relationship. Echocardiographic evidence such as LA enlargement, systolic and/or diastolic LV dysfunction, and increased LV mass may simply reflect an underlying cardiac condition that predisposes to

Conclusions

Dementia is an increasingly important public health challenge, and no curative treatment has thus far been identified. Focusing on the detection of preclinical signs announcing the onset of the disease is, however, highly important in view of the possibility that starting preventive measures early in the course of the disease may prove beneficial. The inclusion of echocardiography may further improve currently used risk assessment models by allowing the detection of subclinical cardiac

Acknowledgments

Sophie Rushton-Smith, PhD, provided editorial support for the final version of this review and was funded by the authors.

References (111)

  • A.L. Jefferson et al.

    Relation of left ventricular ejection fraction to cognitive aging (from the Framingham Heart Study)

    Am J Cardiol

    (2011)
  • M. Suwa et al.

    Correlation between cognitive impairment and left ventricular diastolic dysfunction in patients with cardiovascular diseases

    Int J Cardiol

    (2009)
  • W.P. Abhayaratna et al.

    Left atrial size: physiologic determinants and clinical applications

    J Am Coll Cardiol

    (2006)
  • C.P. Appleton et al.

    Estimation of left ventricular filling pressures using two-dimensional and Doppler echocardiography in adult patients with cardiac disease. Additional value of analyzing left atrial size, left atrial ejection fraction and the difference in duration of pulmonary venous and mitral flow velocity at atrial contraction

    J Am Coll Cardiol

    (1993)
  • C.L. Simek et al.

    Relationship between left ventricular wall thickness and left atrial size: comparison with other measures of diastolic function

    J Am Soc Echocardiogr

    (1995)
  • Z.Y. Lai et al.

    Left ventricular filling profiles and angiotensin system activity in elite baseball players

    Int J Cardiol

    (1998)
  • M.E. Barnes et al.

    Left atrial volume in the prediction of first ischemic stroke in an elderly cohort without atrial fibrillation

    Mayo Clin Proc

    (2004)
  • T.S. Tsang et al.

    Left atrial volume as a morphophysiologic expression of left ventricular diastolic dysfunction and relation to cardiovascular risk burden

    Am J Cardiol

    (2002)
  • J.S. Gottdiener et al.

    Left atrial volume, geometry, and function in systolic and diastolic heart failure of persons > or =65 years of age (the cardiovascular health study)

    Am J Cardiol

    (2006)
  • Y. Takemoto et al.

    Usefulness of left atrial volume in predicting first congestive heart failure in patients > or = 65 years of age with well-preserved left ventricular systolic function

    Am J Cardiol

    (2005)
  • B. Karadag et al.

    Relationship between left atrial volume index and cognitive decline in elderly patients with sinus rhythm

    J Clin Neurosci

    (2013)
  • A.L. Jefferson et al.

    Systemic hypoperfusion is associated with executive dysfunction in geriatric cardiac patients

    Neurobiol Aging

    (2007)
  • C. DeCarli et al.

    Measures of brain morphology and infarction in the framingham heart study: establishing what is normal

    Neurobiol Aging

    (2005)
  • P. Verdecchia et al.

    Left ventricular mass and cardiovascular morbidity in essential hypertension: the MAVI study

    J Am Coll Cardiol

    (2001)
  • Y. Agmon et al.

    Is aortic dilatation an atherosclerosis-related process? Clinical, laboratory, and transesophageal echocardiographic correlates of thoracic aortic dimensions in the population with implications for thoracic aortic aneurysm formation

    J Am Coll Cardiol

    (2003)
  • C. Patterson et al.

    Diagnosis and treatment of dementia: 1. Risk assessment and primary prevention of Alzheimer disease

    CMAJ

    (2008)
  • J.A. Schneider et al.

    Relation of cerebral infarctions to dementia and cognitive function in older persons

    Neurology

    (2003)
  • S.E. Vermeer et al.

    Silent brain infarcts and the risk of dementia and cognitive decline

    N Engl J Med

    (2003)
  • C. Reitz et al.

    Prestroke cognitive performance, incident stroke, and risk of dementia: the Rotterdam Study

    Stroke

    (2008)
  • K.M. Langa et al.

    National estimates of the quantity and cost of informal caregiving for the elderly with dementia

    J Gen Intern Med

    (2001)
  • B.N. Justin et al.

    Heart disease as a risk factor for dementia

    Clin Epidemiol

    (2013)
  • Y. Moon et al.

    Vascular factors are associated with the severity of the neuropsychiatric symptoms in Alzheimer's disease

    Int J Neurosci

    (2014)
  • A. Ott et al.

    Diabetes mellitus and the risk of dementia: The Rotterdam Study

    Neurology

    (1999)
  • J.L. Molinuevo et al.

    Clinical profile of Alzheimer's disease: is the age of the patient a decisive factor? results of the INFLUENCE study

    J Alzheimers Dis

    (2014)
  • S. Kalmijn et al.

    Metabolic cardiovascular syndrome and risk of dementia in Japanese-American elderly men. The Honolulu-Asia aging study

    Arterioscler Thromb Vasc Biol

    (2000)
  • A.M. Hajduk et al.

    Cognitive change in heart failure: a systematic review

    Circ Cardiovasc Qual Outcomes

    (2013)
  • R.L. Vogels et al.

    Cognitive impairment in heart failure: a systematic review of the literature

    Eur J Heart Fail

    (2007)
  • I. Volonghi et al.

    Cognitive outcomes after acute coronary syndrome: a population based comparison with transient ischaemic attack and minor stroke

    Heart

    (2013)
  • L. Kilander et al.

    Atrial fibrillation is an independent determinant of low cognitive function: a cross-sectional study in elderly men

    Stroke

    (1998)
  • C. Rosendorff et al.

    Cardiovascular risk factors for Alzheimer's disease

    Am J Geriatr Cardiol

    (2007)
  • R.A. Charlton et al.

    White matter damage on diffusion tensor imaging correlates with age-related cognitive decline

    Neurology

    (2006)
  • S. Kaffashian et al.

    Predicting cognitive decline: a dementia risk score vs. the Framingham vascular risk scores

    Neurology

    (2013)
  • M.F. Elias et al.

    Framingham stroke risk profile and lowered cognitive performance

    Stroke

    (2004)
  • D.J. Llewellyn et al.

    Framingham Stroke Risk Profile and poor cognitive function: a population-based study

    BMC Neurol

    (2008)
  • Y.D. Reijmer et al.

    Dementia risk score predicts cognitive impairment after a period of 15 years in a nondemented population

    Dement Geriatr Cogn Disord

    (2011)
  • S. Seshadri et al.

    Stroke risk profile, brain volume, and cognitive function: the Framingham Offspring Study

    Neurology

    (2004)
  • F.W. Unverzagt et al.

    Vascular risk factors and cognitive impairment in a stroke-free cohort

    Neurology

    (2011)
  • S. Kaffashian et al.

    Predictive utility of the Framingham general cardiovascular disease risk profile for cognitive function: evidence from the Whitehall II study

    Eur Heart J

    (2011)
  • M. Percy et al.

    Risk factors for development of dementia in a unique six-year cohort study. I. An exploratory, pilot study of involvement of the E4 allele of apolipoprotein E, mutations of the hemochromatosis-HFE gene, type 2 diabetes, and stroke

    J Alzheimers Dis

    (2014)
  • M. Kivipelto et al.

    Midlife vascular risk factors and Alzheimer's disease in later life: longitudinal, population based study

    BMJ

    (2001)
  • Cited by (14)

    View all citing articles on Scopus

    Dr Tzourio has received fees from Fondation de Recherche sur l’Hypertension Artérielle for participating in a scientific committee. Dr Cohen has received a research grant from RESICARD (research nurses) and consulting and lecturing fees from AstraZeneca, Bayer Pharma, Boehringer Ingelheim, Daiichi-Sankyo, GlaxoSmithKline, and Sanofi. All other authors report no conflicts of interest.

    View full text