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Student%20Lecture%2024%20%28Atherosclerosis%29 - Lecture 24...

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Unformatted text preview: Lecture 24 Peripheral Arterial Disease Peripheral Tuesday 4­13­10 Announcements Outline Outline – Proof of completion of online course evaluation. Due 5­7­10. – Proof of attending a Purdue Sporting event (ticket stub and picture) plus ½ page summary of applying concept learned in HK368 to what you observed. Due 5­7­10. – Ultrasound practice subject. Contact: [email protected] Monday and Friday – 8:30am to 12:30pm Tuesday and Thursday – 9:30am Wednesday – 8:30am to 11:30am Quiz 13 – PAD – Seminar – April 14th, 3:30pm, Armstrong 1109 Lecture Grant Assignment #5 Are arteries outside the coronary vasculature also susceptible to atherosclerosis? atherosclerosis? Peripheral arterial disease (PAD): Significant atherosclerotic plaque formation outside the ____________ circulations. ____________ _______ million Americans _______ affected by PAD. affected www.aafp.org. Sites of PAD Localization Sites Susceptible Protected Anatomical Travelogue Inc ©2005 Why is atherosclerosis not homogeneously distributed throughout vasculature? Example of this is the arms being Example of this is the arms being resistant to disease and the legs being prone to disease. Susceptibility to atherosclerosis Arms vs. Legs Arms Hydrostatic Pressure Hypothesis Hydrostatic Blood Pressure 120/74 mmHg Blood Pressure 120/70 mmHg 148/74 mmHg 220/132 mmHg Shear Stress Hypothesis 4C 120 100 80 60 40 20 0 Brachial Superficial Femoral 4D * Oscillatory Shear Index Mean Shear Rate (s-1) * * 0.35 0.30 0.25 0.20 0.15 0.10 0.05 0.00 * * ‡ * Supine Seated Standing Supine Seated Standing Newcomer et al., AJP Heart and Circ Phys, 294(4): H1833­9, 2008 Advanced Stage Atherosclerosis Require Surgical Interventions Require Porth 2007 Effects of Physical Activity on risk for CHD for Morris et al. Lancet 1953 Investigation looking at – – – – Bus drivers (sed) Conductors (active) Postal Clerks (sed) Postmen (active) McArdle, Katch and Katch Effects of Physical Activity on Mortality from PAD Mortality Garg et al. Circulation 2006 Investigated the effects of Results – Individuals with the highest physical activity (4th Quartile) as assessed by questionaire and accelerometer __________________. – Daily physical activity was ________ related to mortality. Garg et al, 2006 Effects of physical activity on progression of atherosclerosis in individuals with CAD individuals Hambrecht et al. 1993. Investigation on the Results 100 Physically active Sedentary 80 Individuals (%) 60 – of exercise lead to regression of atherosclerotic plaque. 40 20 0 Regression No Change Hambrecht et al, 1993 Progression Effects of lifestyle modification on progression of atherosclerosis in individuals with CAD Ornish et al. 1998 Ornish et al. 1998 Investigation on the effects Lifestyle modifications – – – – Results – 10% fat diet Aerobic exercise training Stress management Smoking cessation Ornish et al, 1993 Effectiveness of stents vs. exercise Effectiveness Hambrecht et al, 2004 Investigation into the mortality rates . Result – – Progression Stent (45% of patients) Exercise (32% of patients) Hambrecht et al, 2004 Exercise modifies ___________________ associated Exercise modifies ___________________ associated with atherosclerosis. – – – – – Hypertension Blood lipids Diabetes Obesity Stress What are the underlying mechanisms for the effects of exercise on atherosclerosis? Statistical modeling suggests that ____ of risk reduction associated with exercise cannot be explained by modification of the traditional risk factors listed above! (Green 2008) Shear stress Shear Frictional force produced by blood flowing across endothelial cells. Shear stress increases during exercise – – – Antioxidants SOD­1 eNOS Laughlin et al, 2008 Pressure and Cyclic Strain Pressure Pressure is the downward force created by blood. Cyclic strain is the stretching of endothelial cells. Both pressure and cyclic strain increase during exercise. Laughlin et al, 2008 Synchronous vs. Asynchronous Hemodynamics Hemodynamics Synchronous hemodynmics occur when pressure, flow and diameter all change simultaneously. Unknown if hemodynamics become more synchronous during exercise. Synchronous hemodynamics produce an __________________ genes and a decrease in __________________ – ET­1 – eNOS Laughlin et al, 2008 ...
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