Cardio Flashcards
Non-modifiable Risk Factors for coronary heart disease?
- Men over 45
- Postmenopausal women
- Family hx of CVD for males over 55 and females over 65
Modifiable Risk Factors for coronary heart disease?
- Hypertension
- Smoking
- Dyslipidemia (low HDL or elevates LDL)
- Diabetes Mellitus
- Obesity
- Left ventricular hypertrophy
Is hyperlipidemia common?
Yes! in 40% of pop
What is hyperlipidemia?
- Elevated cholesterol, phospholipids, + triglycerides in blood
Components of a lipoprotein?
How are lipoproteins classified?
Classifications?
= Lipid + Apoprotein
- Classified based on density
LDL, HDL, VHDL
What is an apoprotein?
Proteins that transport lipids
As nurse, will be given what regarding pt lipid diagnostics?
a Lipid Profile
Which lipoprotein causes problems if elevated?
LDL’s
Arrange kinds of lipoproteins in ascending order in terms of density.
Which contain greatest percentage of proteins? And which contain more cholesterol/triglycerides?
(Fig. 22-2 p. 461)
Chylomicrons - lowest density, 2% protein
VLDL - 5-10% protein
LDL - 25% protein
HDL - 50% protein
Are proteins are fats more dense? Which is heavier?
Proteins most dense, are heavier
What is a chylomicron?
Fx to transport fat absorbed in small intestines
- Have lowest density of all lipoproteins
(made up 80-90% triglycerides, 2% protein)
What % of LDL’s is cholesterol?
50% - high!
General structure of a lipoprotein?
Cholesterol esters + tryglycerides located in hydrophobic core of macromolecule, surrounded by phosphlipids + apoproteins
(Fig 22-3 p. 461)
Suffix “sclerosis” refers to?
Prefix “athero” refers to?
Hardening (in many cases)
Soft paste
- Therefore, atherosclerosis = formation and deposition of soft pasty material + hardening
What size of arteries does atherosclerosis typically occur in?
larger arteries
What is an “atheroma”
Where does this form in atherosclerosis
Fibrofatty lesion - forms in intima of larger arteries
Layers of a blood vessel?
Tunica intima: composed of a thin layer of endothelial cells and lines the entire circulatory system
Tunica media: middle layer of smooth muscle + elastic fibres
Tunica externa/adventitia: outermost, loosely woven collagen + elastic fibers (reinforce + anchor vessels) & contains nerves, lymphatic vessels, vasa vasorum
Effect of development of atheroma in atherosclerosis? Ultimate potential outcomes?
Affects perfusion –> ischemia –> stroke, MI, PVD
What is ischemia?
Restricted blood flow at LOCAL level d/t obstruction in blood vessel
What is infarction?
Death of tissue d/t ischemia
PVD = ?
Is this life-threatening?
Peripheral Vascular Disease - not immediately life threatening
Are a large amount of deaths d/t issues that arise from atherosclerosis?
~32% of all deaths in Canada
d/t MI, stroke
3 Stages of lesion that develops in Atherosclerosis?
1) Fatty Streak
- Discoloration of intima
- Lesion contains variety of defence cells
- Is insidious (not yet clinical)
2) Fibrous Atheromatous plaque
- Is basic clinical manifestation
- Pt now experiencing symptoms (?)
- Plaque now has lipids, defence cells, scar tissue + Smooth muscle cells (should NOT be found in intima!)
3) Complicated Lesion
- Now close to death
Can you reverse the changes of blood vessels that take place in atherosclerosis?
Is it possible to remove the obstruction?
No, and cannot remove obstruction because has developed inside vessel wall
Name for macrophages that have engulfed oxidized lipids in atherosclerosis?
What kind of lipids are engulfed primarily?
Foam Cells
LDL’s
How and when does atherosclosis begin?
In 20’s
Begins with subtle injury to endothelium
- Is insidious, with no manifestations until later in life
- Takes decades to develop
How is CRP involved in early detection of the development of atherosclerosis?
With initial endothelial injury, inflammation occurs –> CRP released.
Will see chronic elevated CPR levels…indicating possible vessel damage
Outline development of Atherosclerosis
- Early in development of lesion, endothelial cells begin to express selective adhesion molecules that bind monocytes + other inflammatory cells that initiate atherosclerotic lesions
- Monocytes enter intima –> become macrophages + oxidize and engulf LDL’s (now foam cells)
- Free radicals produced when lipids oxidized by macrophages, which cause more injury + inflm (begins cycle)
- Foam cells release growth factor, causing proliferation of smooth muscle cells
- Atheroma forms
- Adherence and entry of leukocytes + adherence and aggregation of platelets occurs at the atheroma
- Rupture, ulceration, or erosion of unstable or vulnerable fibrous cap may lead to hemorrhage into the plaque or thrombotic occlusion of vessel lumen (hemorraging initiates clotting…thrombus forms…possible MI)
Risk factors that increase chance of endothelial damage leading to atherosclerosis?
High LDL’s
Smoking
Immune mechanisms
Mechanical stress associated with hypertension
Detailed structure of atheroma (p. 471)
- bulge of lipids, fibres, defence cells, smooth muscle cells, etc.);
- has fibrous cap (of smooth muscle cells and extracellular matrix)
- Beneath + to side of fibrous cap = shoulder = macrophages, SMCs, and lymphocytes
- lipid core (lipid-laden foam cells + fatty debris)
T/F: One MI predisposes a person to more MI’s?
T
Name the sites of severe atherosclerosis in order of frequency (fig 22-6 p. 466)
1) Abdominal aorta and iliac arteries
2) Proximal coronary arteries
3) Thoracic aorta, femoral and popliteal arteries
4) Internal carotid arteries
5) Vertebral, basilar, and middle cerebral arteries
What is occurring in heart during systole + diastole?
Systole = heart contraction Diastole = heart filling (relaxation of ventricles)
Four major control systems of BP?
see fig 23-2 on p. 487
1) Arterial baroreceptors
2) RAA system
3) Vascular autoregulation
4) Regulation of Fluid Volume
Arterial baroreceptors in BP regulation?
- Rapid + short-term response
- P sensitive receptors located in walls of blood vessels + heart (carotic + aortic baroreceptors located in heart + brain)
- Respond to changes in P by sending impulse to cardiovascular centres in brain stem to effect changes in HR and vascular smooth muscle tone
Outline RAA system in BP control
- Renin produced by kidneys in response to dec in arterial BP, sympathetic system,
- Renin converts Angiotensinogen to Angiotensin I
- ACE from lungs converts to Angiotensin II
- A II causes :
1) vasoconstriction of systemic arterioles (inc arterial BP)
2) adrenal cortex to release more Aldosterone –> insertion of Na+ channels–> inc Na+ reabsorption …water follows = inc vascular vol + inc arterial BP
3) release of ADH –> H2O channels inserted into DCT + CD, more vasoconstriction
4) Stimulates thirst
ADH produced and released by?
Produced by hypothalamus
Released by post. pituitary
Outline vascular autoregulation with regard to BP control
- Local, controls diameter to change resistance
More details?
aldosterone released from?
Adrenal cortex of adrenal gland
Regulation of fluid volume in maintaining BP?
???
- Long term regulation of fluid volume primarily done by kidneys (humoral + neural both relatively short term)
- Kidneys regulate extracellular fluid volume
Intrinsic controls of kidneys:
1) Myogenic mechanism: afferent arteriole in kidney (brining blood to glomerulus) responds to stretching or not, constricts or relaxes to maintain NFP, GFR
2) Tuboglomerular feedback: rate of filtrate flow in DCT triggers release of vasoconstrictors or vasodilators to afferent arteriole
Hypertension =
Persistant BP > 140/90 at rest
Categories of Hypertension?
Category Systole Diastole
Normal 180 or >110
(Severe hypertension)
Is systolic or diastolic pressure more important in BP?
Equally important
When overlap in categories of BP occur, how to classify?
Put in higher category to err on side of caution
What is primary hypertension?
AKA?
Common?
> 140/90
Aka ESSENTIAL or IDIOPATHIC HTN
- Do not know cause…can bring back to normal but can’t address underlying issue
- Etiology is multifactorial
- Kidney is implicated in all primary hypertension (does not mean kidney is cause but is affected by all compensatory mechanisms and regulates them)
~90% of cases
What is secondary HTN?
Common?
>140/90 Secondary = d/t other problem Identifiable etiology (ex: renal disease) - Just because know underlying cause doesn't mean can always fix it ~10% of cases
2 classifications of HTN based on cause?
Primary + Secondary
Systolic HTN
Systolic >140
Mostly after age 50
Change in vessel compliance: vessels do not accommodate with less elasticity –> inc resistance –>inc systolic P but nomal diastolic
White coat hypertension?
- BP elevate in healthcare setting only
- Reasons not entirely known, not as simple as anxiety…may be vasovagal
Gestation Hypertension
- During pregnancy, does not always go away after pregnancy
- AKA eclampsia
- don’t need to know details
Malignant hypertension
When diastolic P > 120 and systolic is relatively normal
- Very severe, cause not entirely understood
Manifestation of Hypertension? Complications
Elevated BP!
Later complications arise: dizziness, fatigue, palpitations, AM headaches, blurred vision
- Those of progressive organ organ damage (heart, kidneys, eyes, vessels)
Why is BP considered silent killer?
If don’t have appropriate technology to monitor, won’t see it until is serious issue
What are palpitations?
The sensation of rapid, forceful heart beat
Why do AM headaches occur as complication to HTN?
BP has circadian rhythm - is normally highest in morning
Why does blurred vision occur as complication to HTN?
Elevated BP causes aneurysms + rupture of blood vessels in retina
Why does dizziness and fatigue result from HTN?
??
Why do you see progressive organ damage in HTN? (heart, kidneys, eyes, vessels)
- Damage to capillaries of kidneys and eyes
- Vessels deteriorate when continually bombarded by high BP
Treatement of HTN?
1) Will try modification of life-style first (3-6 month trial) - execise, diet, weight; monitored monthly
2) If trial not effective, will try meds: 1st line is diuretics –> inc fluid (H2O + electrolyte) loss from kidneys
3) Then if required, will add one of more of following:
- Ca+ Channel Blockers –> heart contracts less and less forcefully
- Angiotensin II receptor blocker –> less vasoconstriction, reduces BP by mechanisms of A II (via aldosterone, ADH, etc)
- ACE inhibitor (ACE I) –> Angiotensin I no longer catalyzed to Angiotensin II
What occurs in PVD?
- Exactly like atherosclerosis but occurs in peripheral vessels
- Also affects veins + lymphatics
- Changes similar to coronary a. and cerebral a. in that produce ischemia, pain, impaired fx. infarction, tissue necrosis