MNT 2 - Exam #1 (Part 2) Flashcards
What is Atherosclerosis?
-Thickening of the blood vessel walls caused by presence of plaque (AS);
-Begins as fatty, fibrous growth which may calcify over time
— Incompletely understood process;
— Involves endothelial cells, smooth muscle cells, platelets, and leukocytes;
— Begins as a response to endothelial lining injury that results in an inflammatory process;
— AS occudes lumen of blood vessels = ischemia
What can Atherosclerosis lead to?
This can lead to an infarct =
- Myocardial Infarction (MI)/ CAD
- CVA
- Peripheral vascular disease (PVD)
- CHF
What studies have greatly contributed to the epidemiological study of CVD?
- Framingham Study
- National Health and Nutrition Examination (NHANES) Surveys
- National Cholesterol Education Program (NCEP)
What are the risk factors for Atherosclerosis?
- Family history
- Age and gender
- Obesity
- Dyslipidemia
- Hypertension (can initiate AS lesion/ cause plaque to rupture)
- Physical inactivity
- Atherogenic diet
- Diabetes mellitus
- Impaired fasting glucose and metabolic syndrome
- Cigarette smoke
- Sleep Apnea
What was the MRFIT study?
(Multiple Risk Factor Intervention Trial);
- 366,000 men & women;
- Compared mortality rates for “low risk” vs “high risk” individuals
MRFIT “Low Risk”
(ABSENCE of risk factors)
- serum chol. </equal to: 120/80mmHg
- Non-cigarette smokers
MRFIT “High Risk”
(WITH risk factors);
- serum chol. >200;
- BP> 120/80mmHG;
- Smokers
What was the Nurses’ Health Study?
- 84,129 women;
- Identified 5 healthy lifestyle factors
1. No cigarettes
2. ½ glass wine/day
3. 30 mins. or more/day mod./vigorous P.A.
4. BMI< 25
5. Diet with:
6. lower Trans fats & glycemic load,
7. Higher cereal fiber, omega 3’s,folate, and P/S ratio
What were the results of the Nurses Health Study?
- 14 year period =
- 3 healthy factors present: risk of CHD reduced by 57%;
- 4 healthy factors present: risk reduced by 66%;
- 5 healthy factors present: risk reduced by 83%
What defines Obesity?
- Major Risk Factor of so many diseases!;
- BMI = >29.9
- Waist Circumference (40 men, 35 women);
- *NCEP Adult treatment panel III (ATPIII) identified waist girth alone as suitable identifier of risk
What other Atherosclerosis risk factors are associated with Obesity?
- Dyslipidemia
- HTN
- Physical Inactivity
- Diabetes
What does a LOW level of Adiponectin predict?
- Hypertension
- Myocardial infarction
- Coronary dysfunction
- All related to high levels of LEPTIN;
- *Adiponectin DECREASES with decreased adipose tissue
How is HTN a risk factor for atherosclerosis?
[HTN = CV condition & risk factor for other forms of CVD]
- Mechanism =
1. Increased pressure against endothelium can cause initial lesion;
2. Changes in pressure can cause established plaque to rupture leading to an event such as infarct or proliferation of plaque; - Site = Force of BP amplified where vessels branch b/c obstructive plaque is more common in these areas
How does BP related to Atherosclerosis?
Elevated Blood Pressure/Hypertension Remains One of the Most Important Multipliers for Cardiovascular Risk:
What is a BP of >140/90mmHG associated with?
- 69% of first myocardial infarctions;
- 74% of cases of coronary heart disease;
- 77% of first strokes;
- 91% of cases of heart failure;
- 277,000 deaths in 2003;
- $63.5 billion annually (direct/indirect)
How is Physical Inactivity related to Atherosclerosis?
Impact of Physical Inactivity on CVD risk similar to: impact of dyslipidemia, HTN, cigarettes
What are the BENEFIT of ACTIVITY?
- Decreases BP;
- Decreases TAG;
- Increases HDL cholesterol → HAS NOT show to reduce LDL cholesterol or total cholesterol → ONLY raises good, doesn’t lower the bad;
- Improves endothelial function;
- Decreases platelet aggregation;
- Helps with weight reduction
Risk for Death related to Fit vs. Unfit MEN:
- Normal Weight – Unfit 3.1X greater risk;
- Overweight – Unfit 4.5X greater risk (fit 1.5X);
- Obese – Unfit 5X greater risk (fit 1.6X)
What were the results of the Nurse’s health study and Fit vs. Unfit Women?
1. Normal Weight — Less than 1hr PA = 2.9X — 1-3.5hr/wk PA = 1.6X — More than 3.5hr/wk PA = 1X 2. Overweight — Less than 1hr PA = 4.3X — 1-3.5hr/wk PA = 2.1X — More than 3.5hr/wk PA = 1.5X 3. Obese — Less than 1hr PA = 4.7X — 1-3.5hr/wk PA = 2.5X — More than 3.5hr/wk PA = 1.9X
How do glucose abnormalities related to Atherosclerosis?
— Impaired fasting glucose associated with increased risk of CVD mortality; IFG = plasma glu of 110-125mg/dL;
— CVD Mortality risk with Diabetes:
-CAD = most common cause of death for patients with DM
-Individuals with type 1 and 2 DM have 2-4 times greater CVD mortality risk than non diabetics
What are the Metabolic Risk Factors?
- Abdominal obesity – waist cir. >40in. Men/ 35in. women;
- Insulin resistance – FBG>/=100mg/dL or previously diagnosed T2DM;
- Dyslipidemia – any abnormalities in a lipid panel;
- TAG >/= 150mg/dL;
- HDL cholesterol < 40mg/dL men; < 50mg/dL women;
- HTN – BP >/= 130/85 mmHg or previously dx’s HTN;
- Prothrombotic state = abnormality in blood coagulated
What is the NCEP Definition of Metabolic Syndrome?
(National Cholesterol Education Program);
-Individual has 3 metabolic risk factors
What else is seen elevated with Metabolic Syndrome?
-Higher CRP seen w/ Metabolic syndrome);
→ CRP (C-reactive protein) is an acute phase reactant, a protein made by the liver and released into the bloodstream within a few hours after tissue injury, the start of an infection, or other cause of inflammation
What is the mechanisms for vascular injury in DM?
(Metabolic syndrome);
-Dyslipidemia = low HDL; high Triglycerides;
-Hypertension;
-Obesity;
-Hyperglycemia
= Increased Free Fatty Acids cause endothelial dysfunction and are PRO-inflammatory
= Oxidative Stress is increased by multiple cardiovascular risk factors
How are LESIONS in the arteries formed?
- Damage to endothelial layer = inflammatory process = attracts platelets;
- Platelets attach to endothelium and form small Clot (mural thrombus);
- Platelets adhere to subendothelial surface & secrete Adenosine diphoshate (ADP) and platelet derived growth factor (PDGF).
What are the effects of ADP and PDGF?
- ADP and PDGF respectively promote platelet aggregation and attract monocytes, smooth muscle cells, and other cells.;
- Net result: increase in collagen and other fibrous growth;
- Plaque increases in size causing artery to EXPAND outward
Stage 1 of Plaque Progression
-Monocytes (phagocytic WBCs) circulate in bloodstream and respond to injury in artery wall
Stage 2 of Plaque Progression
- Monocytes slip under blood vessel cell and engulf LDL cholesterol making FOAM CELLS;
- Thin layer of foam cells develops = FATTY STREAK
Stage 3 of Plaque Progression
- Fatty streak thickens and forms plaque that accumulates more lipids, smooth muscle cells, collagen, and debris;
- If artery expands to accomodate thickening plaque, and contains a large lipid core with a fibrous coating, it is vulnerable to rupture and thrombosis
What are the classes of Lipoprotiens?
- Chylomicrons, VLDL, and their catabolic remnants;
- LDL;
- HDL
