This Article Figures Only Full Text Full Text (PDF) All Versions of this Article: j.jacc.2006.10.058v1 49/9/939    most recent Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Silber, H. A. Articles by Ouyang, P. Search for Related Content PubMed PubMed Citation Articles by Silber, H. A. Articles by Ouyang, P.

CLINICAL RESEARCH: VASCULAR DISEASE

Arterial Reactivity in Lower Extremities Is Progressively Reduced as Cardiovascular Risk Factors Increase

Comparison With Upper Extremities Using Magnetic Resonance Imaging

Harry A. Silber, MD, PhD^_*,_*, Joao A.C. Lima, MD, FACC^_*,, David A. Bluemke, MD, PhD, Brad C. Astor, PhD, Sandeep N. Gupta, PhD, Thomas K. Foo, PhD and Pamela Ouyang, MD, FACC^_*

^_* Department of Medicine, Division of Cardiology, and the
Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland
Johns Hopkins University School of Public Health, Baltimore, Maryland
General Electric Healthcare Technologies, Milwaukee, Wisconsin

Manuscript received July 17, 2006; revised manuscript received October 20, 2006, accepted October 27, 2006.

^_* Reprint requests and correspondence: Dr. Harry A. Silber, Cardiology A-1 East, Johns Hopkins Bayview Medical Center, 4940 Eastern Avenue, Baltimore, Maryland 21224. (Email: hsilber{at}jhmi.edu).

OBJECTIVES: Our goal was to investigate whether the association between established cardiovascular risk factors and arterial reactivity differs between the lower and upper extremities.

BACKGROUND: Resistance artery reactivity in the arm is associated with cardiovascular risk factors, coronary disease, and events. However, the relationship of lower versus upper extremity vasoreactivity to increasing cardiovascular risk factors has not been determined.

METHODS: We studied 82 subjects in 3 groups: 33 young healthy (YH) (21 to 41 years), 30 older healthy (OH) (>50 years), and 19 older type 2 diabetic subjects (OD). We directly measured systolic shear rate, flow, and radius in brachial and femoral arteries at rest and during post-occlusion hyperemia using magnetic resonance imaging.

RESULTS: Brachial and femoral systolic shear rate, flow, and radius were similar among the groups at rest. Brachial hyperemic shear rate and hyperemic flow normalized as a function of baseline radius were not statistically different when YH were compared with OH and OH with OD. In contrast, femoral hyperemic shear rate and hyperemic flow normalized to baseline radius were lower in OH than YH (680 ± 236 s^–1 vs. 843 ± 157 s^–1, p = 0.001, and 0.84 ± 0.25 mm^1.27/s vs. 1.01 ± 0.16 mm^1.27/s, p = 0.001) and lower in OD than OH (549 ± 183 s^–1, p = 0.02, and 0.74 ± 0.19 mm^1.27/s, p = 0.046).

CONCLUSIONS: Persons with increasing cardiovascular risk factor burden had progressively reduced arterial reactivity in lower but not upper extremities. This may help to explain why atherosclerosis usually develops more severely in legs than in arms, and suggests that legs may be more sensitive than arms for assessing early global atherosclerotic risk.

Abbreviations and Acronyms   FMD = flow-mediated dilation   HDL = high-density lipoprotein   HypQ = hyperemic flow   MRI = magnetic resonance imaging

This article has been cited by other articles:

				V. R. S. Fernandes and J. A. C. Lima Functional Coronary Imaging with Magnetic Resonance: A "Renaissance"? Radiology, December 1, 2011; 261(3): 685 - 687. [Full Text] [PDF]

				R. House, D. Jiang, A. Thompson, T. Eger, K. Krajnak, J. Sauve, and M. Schweigert Vasospasm in the feet in workers assessed for HAVS Occup. Med., March 1, 2011; 61(2): 115 - 120. [Abstract] [Full Text] [PDF]

				B. A. Parker, T. L. Trehearn, and J. R. Meendering Pick your Poiseuille: normalizing the shear stimulus in studies of flow-mediated dilation J Appl Physiol, October 1, 2009; 107(4): 1357 - 1359. [Full Text] [PDF]

				S. K. Nishiyama, D. W. Wray, and R. S. Richardson Aging affects vascular structure and function in a limb-specific manner J Appl Physiol, November 1, 2008; 105(5): 1661 - 1670. [Abstract] [Full Text] [PDF]