Population Health Research Institute
Atherosclerosis Imaging

Atherosclerosis Imaging
Understanding the causes and evaluating new methods of preventing cardiovascular disease

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"Being able to measure atherosclerosis noninvasively and repeatedly in the same person gives us unique insights into how the early seeds of atherosclerotic disease grows and can be influenced by how we live or by treatments."

-Dr. Eva Lonn


Overview

The Vascular Ultrasound Imaging Laboratory of the Population Health Research Institute has standardized methods for the non-invasive assessment of sub-clinical atherosclerosis and endothelial function. ultrasound Imaging is used also for research studies of  left ventricular structure and function.  Major techniques used in the laboratory include quantitative B-mode carotid ultrasonography with measurements of carotid intima-media thickness (IMT) of the extra cranial carotid arteries and assessment of carotid plaques, studies of brachial reactivity or flow mediated dilation of the brachial artery which are an in vivo assay of endothelial function, studies of endothelial function using pulsed arterial tonometry and echocardiographic studies of cardiac structure and function.

More recently computed tomographic coronary angiography and intravascular ultrasound are also increasingly used in research aimed at enhancing our understanding of the determinants, the diagnosis and the management of coronary artery disease.


Key Discoveries

The laboratory has used these techniques in epidemiological studies evaluating associations between various risk factors and vascular structure and function and in clinical trials, which have evaluated the effect of various interventions on atherosclerosis. Additionally, this research group has conducted studies evaluating determinants of left ventricular size and function and the effects of various interventions on these parameters of cardiac function.

Their studies have ranged from patients with advanced cardiovascular disease, to general population studies and to investigations in people with other conditions which may increase the risk of atherosclerosis, such as HIV, obese subjects and people with chronic obstructive pulmonary disease. More recently, the laboratory has started a program of atherosclerosis imaging in children. This program is aimed at detecting early stages of atherosclerosis in a pediatric population and defining cardiovascular risk factors at very young ages.


Studies


Main Publications

Lonn E, Yusuf S, Dzavik V, Doris I, Yi Q, Smith S, Moore-Cox A, Bosch J, Riley WA, Teo KK, for the SECURE Investigators. Effects of ramipril and of vitamin E on atherosclerosis: results of the prospective randomized Study to Evaluate Carotid Ultrasound changes in patients treated with Ramipril and vitamin E (SECURE). Circulation 2001; 103:919- 925.

Anand S, Yusuf S, Vuksan V, Devanesen S, Teo KK, Montague PA, Kelemen L, Yi Qilong, Lonn E, Gerstein H, Hegele R, McQueen M. Differences in risk factors, atherosclerosis and cardiovascular disease between ethnic groups in Canada:  the Study of Health Assessment and Risk in Ethnic groups (SHARE). Lancet 2000;356:279-284. 

Anand S, Yusuf S, Jacobs R, Davis AD, Gerstein H, Montague PA, Lonn E. Risk factors, atherosclerosis, and cardiovascular disease among Aboriginal People in Canada (SHARE-AP). Lancet 2001; 358:1147-53. 

Lonn E, Shaikholeslami R, Yi Q, Bosch J, Sullivan B, Tanser P, Magi A, Yusuf S. Effect of ramipril on left ventricular mass and function in normotensive highrisk patients with preserved left ventricular ejection fraction: a sub study of the HOPE trial. J Am Coll Cardiol 2004: 43:2200-2206.  

Yan R, Anderson TJ, Charbonneau F, Title L, Verma S, Lonn E. Relationship between carotid intima-media thickness and brachial artery flow-mediated dilation in middle-aged healthy men. J Am Coll Cardiol; 2005; 45:1980-1986.  

Persson H, Lonn E, Edner M, Baruch L, Lang CC, Morton JJ, Ostergren J, McKelvie RS; Investigators of the CHARM Echocardiographic Substudy-CHARMES. Diastolic dysfunction in heart failure with preserved systolic function: need for objective evidence:results from the CHARM Echocardiographic Substudy-CHARMES. J Am Coll Cardiol. 2007;49:687-94.  

Prevalence and predictors of subclinical atherosclerosis among asymptomatic "low risk" individuals in a multiethnic population.Grewal J, Anand S, Islam S, Lonn E; SHARE and SHARE-AP Investigators. Atherosclerosis. 2008 ;197:435-42.  

Cardiac function stratification based on echocardiographic or clinical markers of left ventricular filling pressures predicts death and hospitalization better than stratification by ventricular systolic function alone Ogunyankin KO, Day AG, Lonn E. Echocardiography. 2008 Feb;25(2):169-81.

Odueyungbo A, Smieja M, Thabane L, Smaill F, Gough K. Gill J, Anderson T. Elston D, Smith S, Beyene J, Lonn E for the Canadian HIV Vascular Study Investigators. Comparison of brachial and carotid artery ultrasounds for assessing extent of  subclinical atherosclerosis in HIV: a prospective cohort study. AIDS Res Ther 2009;6(1)11.

Lonn E, Gerstein H, Sheridan P, Smith S, Diaz R, Mohan V, Bosch J, Yusuf S, Dagenais G for the DREAM (Diabetes Reduction Assessment with ramipril and rosiglitazone Medication) and STARR Investigators. Effect of ramipril and of rosiglitazone on carotid intima-media thickness in people with impaired glucose tolerance or impaired fasting glucose.  J Am Coll Cardiol 2009;53:2028-2035. 

Morrison, KM, Dyal L, Conner W, Helden E, Newkirk L, Yusuf S, Lonn E. Cardiovascular risk factors and non-invasive assessment of subclinical atherosclerosis in youth. Atherosclerosis; in press.

Sheth T, Amlani S, Ellins ML, Mehta S, Velianou J, Cappelli G, Yang S, Natarajan M. Computed tomographic coronary angiographic assessment of high-risk coronary anatomy in patients with suspected coronary artery disease and intermediate pretest probability, Am Heart J. 2008: 155: 918-23. 

Morrison KM, et al. Cardiovascular risk factors and non-invasive assessment of subclinical atherosclerosis in youth. Atherosclerosis (2009), doi: 10.1016/j.atherosclerosis.2009.07.034.

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