Hypertension Flashcards
5 major forms of cardiovascular disease
- hypertension
- atherosclerosis
- ischemic heart disease
- peripheral vascular disease
- heart failure
what are the 3 leading causes of death in canada
- cancer
- diseases of the heart
- cerebrovascular diseases
what is a major risk factor of hypertension? how can we establish this?
Age
prevalence increases with age (higher in males vs females)
and at 65+ equal for male and females, still with a higher prevalence
-> linear relationship
what is the leading reason for visits to physicians in canada?
hypertension
____ are one of the most expensive drug categories
antihypertensives
the lifetime risk for developing hypertension among adults aged 55 to 65 years with normal blood pressure is ___
90%
which population have the highest rate? lowest rate?
- highest: african-americans (44%)
- lowest: Chinese, Koreans (17%)
what are the 2 phases of the cardiac cycle?
systolic (contraction) and diastolic (resting)
cardiac output formula
stroke volume x heart rate
peripheral resistance formula
(length of vessel x viscosity of the blood)/radius^4
relationship between vasoconstriction and resistance
in vasoconstriction - resistance increases
relationship between vasodilation and resistance
in vasodilation - resistance decreases
mean arterial pressure MAP formula
cardiac output x peripheral resistance
what are the 4 factors regulating blood pressure (MAP)
- sympathetic nervous system
- renin-angiotensin aldosterone system
- renal function
- hormones involved: epinephrine, vasopressin, angiotensin 2
which factors modulate heart rate + direction
- parasympathetic activity decreases HR
- sympathetic activity and epinephrine increase HR
the kidneys sense _____ which causes the release of ____
decrease in sodium, extracellular fluid, and arterial blood pressure which causes the release of RENIN
the liver releases ____ which reacts with ____ to make _____
angiotensinogen which reacts with renin to make angiotensin 1
the lungs produce ____ which reacts with ____ making ____
angiotensin-converting enzyme reacts with angiotensin 1 making angiotensin 2
angiotensin 2 positively regulates: (4)
- adrenal cortex
- vasopressin
- thirst
- arteriolar vasoconstriction
adrenal cortex release ___ which stimulates ___. what are the consequences
aldosterone stimulates kidneys which results in sodium reabsorption by kidney tubules which osmotically holds more water in ECF -> water conserved and helps correct low ECF volume
effects of vasopressin
water reabsorption by kidney tubules
____ + ____ + _____ = increase osmolality, increase blood volume and blood pressure
water reabsorption + fluid intake + vasoconstriction
what are the target organ damage related to hypertension
- heart: left ventricle hypertrophy, coronary heart disease, congestive heart failure
- kidneys: renal failure, proteinuria
- bigger vessels: peripheral vascular disease/atherosclerosis
- eyes: retinopathy
- brain: hemorrhage, stroke, dementia
how do you measure blood pressure
sphygmomanometer in mmHg (millimetres of mercury)
causes of hypertension can either be ___ or ___
primary/essential or secondary
what are primary/essential/idiopathic causes of HTN
they represent 95% of cases
- unknown etiology
- interaction from environmental and genetic factors (predisposition)
- influenced by dietary and behavioural factors (PA, smoking, sleeping)
what are secondary causes of HTN
they represent 5% of cases
- occurs secondary to another condition such as renal, endocrine, or neurological disorders
why do we refer to HTN as the “silent killer”
because HTN is typically asymptomatic - you die from HTN due to target organ damage
which are non-modifiable risk factors of HTN
- age >60y
- men, postmenopausal women, ethnicity
- family history of CVD: women <65y or men <55y
which are modifiable risk factors of HTN
- smoking
- sedentary lifestyle
- abdominal obesity, insulin resistance
- excess sodium intake
- poor diet quality
- stress
why are excessive secretion of vasopressin and angiotensin 2 contributing factors to HTN
increased vasoconstriction and fluid retention - high blood pressure
mechanism of smoking on HTN
interferes with nitric oxide which impairs endothelial vasodilation
mechanisms of renal disease/atherosclerosis on HTN
reduced blood flow -> increased angiotensin 2 -> vasoconstriction + sodium/chloride/water retention -> increase in blood volume
mechanism of adrenal disorders on HTN
adrenal disorders that increase secretion of epinephrine and norepinephrine causes vasoconstriction and increases cardia output
____ is associated with HTN but the mechanisms are unclear
hyperinsulinemia
what is the normal range of systolic blood pressure and diastolic blood pressure
90-119 mmHg and 60-79 mmHg
Blood pressure
systolic/diastolic
how does hypertension canada stratify patients?
by cardiovascular risk and based on that risk, there are different threshold and targets for treatment
what are the 4 stratification categories?
- low risk
- moderate-to-high risk
- diabetes mellitus
- hypertension canada high risk patient
characteristics of a person categorized as “low risk” for hypertension
- person with some HTN
- no target organ damage or cardiovascular risk factors and 10-year global risk inferior to 10%
characteristics of a person categorized as “medium-to-high risk” for hypertension
multiple cardiovascular risk factors and 10-year global risk 10-14%
characteristics of a person categorized as “diabetes mellitus” for hypertension
- higher chronic blood glucose
- higher risk at cardiovascular risk
characteristics of a person categorized as “high-risk patient” for hypertension
- > 50y
- AND with systolic blood pressure between 130-180 mmHG [normal 90-119mmHg]
- AND with one or more of the following CV risk factors should be considered for intensive BP management:
. clinical or subclinical cardiovascular disease
. chronic kidney disease (non-diabetic nephropathy, proteinuria)
. estimated 10-year global cardiovascular risk >15%
. age >75y
threshold for initiation of antihypertensive therapy and targets for LOW risk patients
- threshold: SBP >160 DBP >100
- treatment: SBD <140 DBP <90
threshold for initiation of antihypertensive therapy and targets for MODERATE TO HIGH risk patients
- threshold: SBP >140 DBP >90
- treatment: SBD <140 DBP <90
threshold for initiation of antihypertensive therapy and targets for DIABETIC patients
- threshold: SBP >130 DBP >80
- treatment: SBD <130 DBP <80
threshold for initiation of antihypertensive therapy and targets for HIGH RISK patients
- threshold: SBP >130
- treatment: SBD <120
observation made when looking at threshold and treatment between low risk and high risk patients
threshold is higher for low risk patients but lower for high risk - you need to start treating high risk patients as soon as possible even if BP is not that high
=> concept of overall risk for cardiovascular diseases
what is the preferred method for blood pressure measurement
Oscillometric (electronic) - patients can do it themselves [having BP measured by doctor can be stressful - influence BP]
benefits of ambulatory BPM
measure BP out of the doctor’s office which could be stressful in itself and influence BP - used when the BP is just at a limit that could be diagnosed as HTN + measures throughout day and night time - more representative of overall BP
what is the threshold value for diagnosis of HTN for a patient with diabetes?
OBPM > 130/80 -> lower threshold value than for a patient with no diabetes [140/90]
what is the threshold value for a patient with no diabetes that has a mean office BP lower than 180/110?
OBPM >140/90
what is WCHT
white coat hypertension - hypertension related to stress of being at the doctors
what is the general threshold for diagnosis of HTN
> 135/85
what are the hypertension therapy goals?
- reduce risk of CVD and renal disease
- Lower BP to clinically appropriate level
what does the comprehensive plan for HTN therapy include?
- physical activity
- weight reduction
- nutrition therapy
- moderation in alcohol, relaxation therapy, smoking cesation
- pharmacological interventions
what are the pharmacological interventions available for treating HTN
- loop diuretics;
- thiazides;
- carbonic anhydrase inhibitors;
- potassium sparing diuretics
what si the basis for HTN therapy?
lifestyle modifications, if not sufficient then you add medication
what are the dietary factors involved in HTN
- high calories, excess weight, obesity
- sodium
- potassium
- calcium
- magnesium
- alcohol
in adults <55y there is a direct link between ___ and ___
excess weight and hypertension
-> 60% of those with excess weight [abdominal obesity more specifically] and normal BP will develop HTN in the next 4 years
what are the causes of HTN associated with obesity
- insulin resistance/hyperinsulinemia
- overactivity of sympathetic nervous system with obesity
- alteration of RAAS [overproduction of aldosterone]
- leptin increases sympathetic activity [in obesity there is some form of leptin resistance - satiety function isn’t working properly]
what is the most potent non-pharmacological approach to treating HTN
weight loss - greatest decrease in BP among all of the interventions that are not drugs
what is the reduction of BP per 10kg loss
5-20mmHg per 10kg loss
weight loss is indicated both in ___ and ___ of HTN
treatment and prevention
all overweight patients should achieve a weight loss of ___ why?
5kg -> reduce SBP by 4.4 mmHg and DBP by 3.6mmHg to reduce BP and risk for organ damage
what are some weight loss approaches in HTN treatment
- diet education and instruction
- increase in PA
- behavior modification
weight loss may be more difficult in patient using ____. why?
beta-blockers for cardiac disease because these will lower sympathetic activity -> lower metabolism and weight gain
what is the relationship between systolic BP and urinary sodium excretion
linear relationship
measuring serum sodium is a good reflection of sodium intake. True or false?
False, when sodium intake increases the RAAS system maintains sodium concentration in a very tight range therefore any excess is excreted which is why sodium excretion is the best method to reflect sodium intake
lower sodium intake ____ SBP
reduces
which population is more responsive to diet lower in sodium
hypertensive people although normotensive also see an improvement in SBP
african-american
middle-aged
diabetic, renal disease
high sodium intake increases risk of complications in hypertensive patients such as
Coronary heart disease death, Cardiovascular disease death and all death
when comparing American diet and DASH diet with the same amount of sodium intake, which diet shows a greater reduction in BP when lowering the sodium intake?
American diet
which is better: American diet with reduced sodium intake or DASH diet with more liberal sodium intake?
DASH with more liberal sodium intake -> DASH diet associated BP lines are much lower than the control diet regardless of sodium intake
what can explain the heterogeneity observed regarding salt sensitivity
- familial/genetic factors
- age
- severity of HTN
- degree of restriction
- renin-angiotensin-aldosteron (low renin)
- sympathetic response (high NE response)
- duration of trials
salt sensitivity is largely influence by ____
POTASSIUM: high potassium intake - lower sodium sensitivity
good ___ intake is protective against BP
potassium
if diet is high in ___, higher ___ won’t affect much the increase of BP
potassium
sodium
dietary sodium DRI
adequate intake
14-50: 1500mg Na/day
51-70: 1300mg/day
what is the upper limit of sodium
2300 mg Na/day for all adults
to decrease blood pressure, consider reducing sodium intake towards ____ per day
2000 mg Na per day aka 5g of salt
80% of average sodium intake is ____
processed foods
breads are ___ in sodium but are _____
lower in sodium but are big contributors because they are eaten in higher amounts
choose foods with less than ___ per serving
120mg Na
choose foods with sodium that have a % daily value of ____
5% or less
to whom are sodium control diets bets for?
hypertensive people and those with renal diseases
overall, reducing sodium intake:
- reduces BP in most cases
- prevents HTN
- has an additive effect to antihypertensive medications -> lower doses and better control
- reduces risks of complications
relationship between potassium intake and BP
- inverse relationship
- decrease in mean blood pressure
- decreased prevalence in HTN with higher K intake
what are the mechanisms involved in potassium decreasing BP?
- natriuresis [sodium secretion in urine]
- suppressed renin
- attenuates vascular contraction -> vasodialtion
- may reduce sympathetic activity and angiotensin
higher sodium intake favours ___
potassium excretion
our kidneys and RAS system are programmed to ____ [basis of our physiology]
conserve sodium and excrete potassium if in excess
recommended daily dietary intake of potassium
> 60mmol (2300mg) -> associated with decreased risk of stroke mortality (+50mmol reduced BP)
potassium supplementation above daily dietary intake of 60mmol/day os recommended as a treatment for hypertension. true or false
false - emphasize fruit and vegetable + dairy intake which will allow for sufficient potassium intake
what are the risk factors for hyperkalemia
- patients using RAAS inhibitors
- patients receiving other drugs causing hyperkalamia [retention of K]
- chronic kidney disease
- baseline serum potassium >4.5mmol/L
___ intake is inversely associated with BP
calcium
what are the mechanisms of increased calcium itnake
- increased sodium excretion
- increased sensitivity to nitric oxide -> vasodilation
- reduced production of superoxyde and prostanoids (vasoconstrictors)
calcium supplementing above daily recommended dietary intake is not recommended as a treatment for ___
hypertension
relationship between magnesium and BP
inverse relationship
mechanism of magnesium on BP
relates to vascular structure and function: regulates vascular reactivity and contractility
what are the recommendations for magnesium intake
increase dietary intake to reach DRI (menL 420mg/d; women 320mg/d)
alcohol intake has an immediate _____ effect but followed by ____ in the next 10-15h
vasovagal (decrease BP)
elevated BP
effect of moderate alcohol consumption
does not raise BP and has cardioprotective effects
recommendations for alcohol consumption
- limit to 2 drink per day for men
- limit to 1 drink per day for women
what are the routine lab tests done for assessment fo HTN
- urinalysis to see excretion of electrolytes
- blood chemistry (K+, Na+, creatinine)
- fasting blood glucose or Arc1 [hemoglobin Arc1 - marker for longer term blood glucose]
- serum lipid profile [stratification of HTN - overall cardiovascular risk]
how is hypertension assessed
- routine lab testing
- electrocardiogram (ECG)
- target organ damage
- cardiovascular risk score
- physical activity
which are the possible nutrition diagnoses for HTN
- excessive energy intake
- excessive or inappropriate intake of fats
- excessive sodium intake
- inadequate calcium, fibre, potassium, or magnesium intake [inverse relationship with those nutrients and HTN]
- overweight/obesity
- food and nutrition knowledge deficit
which are the health behaviour recommendations for treatment of HTN
- weight reduction [BP decreased by 5-10mmHg/10kg loss]
- eating healthier [DASH-like]
- being more physically active
- moderation in alcohol intake [abstain or limit to <2/day]
- relaxation therapies
- smoking cessation
what are the recommendations for exercise and hypertension
- accumulation of moderate PA of 30-60min/day on most days IN ADDITION to daily activities
- higher intensities are NOT more effective at reducing BP
- for HTN up to 160/99 mmHg: resistance exercise does not negatively impact BP
- recommend gradual increase to 30-60min/day of moderate intensity
what does DASH diet stand for
dietary approach to stop hypertension diet
what is the rational behind the DASH diet
negative correlations between blood pressure and certain nutrients intake (potassium, calcium, magnesium, fibres and proteins) therefore you increase intake in these
> combine a diet that contains a lot of fruits and vegetables, whole grains, low fat dairy, restriction on total fat, saturated fats, dietary cholesterol, and salt
what are the results/benefits of the DASH diet
- average reduction of 5.5 mmHg SBP and 3 mmGh DBP more in DASH vs control
- further decrease in hypertensive subjects
- half of the DASH effects were observed for the high F&V diet vs control
what is the carbohydrate goal in the DASH diet
55%
what is the protein goal in the DASH diet
18%
what is the total fat goal in the DASH diet
27%
what is the saturated fat goal in the DASH diet
6%
what is the sodium goal in the DASH diet
2300mg
what is the potassium goal in the DASH diet
4700mg
what is the calcium goal in the DASH diet
1250mg
what is the magnesium goal in the DASH diet
500mg
what is the fiber goal in the DASH diet
30g
which foods are major sources of energy and fiber
whole wheat bread and rolls, whole wheat pasta, English muffin, pita bread, bagel, cereals, oatmeal, brown rice, unsalted pretzels and popcorn
rich sources of potassium magnesium and fiber (vegetables)
broccoli, carrots, collards, green beans, green peas, kale, lima beans, potatoes, spinach, squash, sweet potatoes, tomatoes
important source of potassium magnesium and fibre (fruits)
apples, apricots, bananas. dates, grapes, oranges, grapefruit, mangoes, melons, peaches, pineapple, strawberries
major sources of calcium and protein
fat free or low fat milk or buttermilk, fat free, low fat or reduced fat cheese, fat free or Low fat regular frozen yogurt
rich sources of protein and magnesium
select only lean, trim away visible fats, broil, roast, poach, remove skin from poultry
rich sources of energy, magnesium, protein, and fiber
almonds, hazelnuts, mixed nuts, peanuts, walnuts, sunflower seeds, peanut butter, kidney beans, lentos, split peas
27% of calories as fat including fat in or added to foods which include
soft margarine, vegetable oil (canola, corn, olive, safflower), low fat mayo, light salad dressing
sweets should be low in fat. examples
fruit flavoured gelatin, fruit punch, hard candy, jelly, maple syrup, sorbet and ices, sugar
what is the main difference between DASH and mediterranean diet
Medi diet is low in dairy
observations of healthy diets similar to DASH-sodium diets rich in CHO, rich in protein, rich in UFA
all diets reduced BP, LDL-C and cardiovascular risk
diets high in protein and unsaturated FA further decreased blood pressure in hypertensive individuals
comparing typical DASH-diet vs. higher-fat/low CHO DASH diet
- similar decrease in blood pressure
- decrease triglycerides and large and medium VLDL particle concentrations
- did not decrease LDL-c but increased LDL peak particle diameter [LDL particle size increased - less atherogenic, less cholesterol esters in larger LDL particles]
=> depends on type of fat
Benefits of DASH diet
improves:
- BP
- LDL
- VLDL
- TG
examples of antihypertensive drugs
- thiazide diuretics
- distal tubular diuretics
- angiotensin converting enzyme (ACE) inhibitors
- angiotensin 2 receptor blockers (ARB)
- calcium channel blockers (CCB)
- beta blockers
- single pill combination (SPC) [combine 2 different medications that act through different mechanisms of action aka ACE inhibitor with calcium blocker]
what is the mechanism of diuretic treatments
> more urine produced
- decreased reabsorption of Na and K
- production of osmotic diuresis
- increased excretion of Na and K
- inhibit action of aldosterone
about loop diuretics
- excrete more potassium, diet should be providing alot of potassium + supplementation
- i.e. furosemide
- most prescribed drug
- side effects: hypokalemia, hyperglycemia [pb of insulin secretion]
about thiazides diuretics
- potassium excretion
- hydrochlorothiazide
- side effects: hypokalemia, hyperglycemia
for both loop and thiazides, what is the dietary approach
- provide potassium rich foods
- provide potassium supplements
about potassium sparing diuretic
- spironolactone, triamterene, amiloride
- avoid excess dietary potassium and supplements
- avoid salt substitutes [potassium chloride]
- avoid excess water consumption
- take with food
- avoid natural licorice
why should one avoid natural licorice
natural licorice interacts with medication
it comes from root and contains an acid that acts by stimulating cortisol production. effect on creating a state of production of aldosterone
-> plays against antihypertensive medication
about ACE inhibitors
- ramipril
- inhibits conversion of angiotensin 1 to angiotensin 2 -> decrease vasoconstriction, vasopressin, inhibits aldosterone release
- side effects/interactions: hypotension, dry cough, side effects are more prevalent in African Americans, avoid salt substitutes, avoid natural licorice
about angiotensin 2 receptors blockers (ARB)
- valsartan, losartan
- usually used when ACEi are not tolerated
- block angiotensin 2 receptor and therefore decrease its activity -> vasodilation, reduced vasopressin and aldosterone
- side effects/interactions: hyperkalemia, avoid salt substitutes and natural licorice, caution with grapefruit for Losartan
why should one be cautious when eating grapefruit whilst taking losartan (ARB) or felodipine (CCB)
it contains a molecule that can interact with cytochrome P4-50 involved in drug metabolism
P4-50 is slightly inhibited by grapefruit molecule and drug will be found in higher levels in blood than what is normally expected
about calcium channel blockers
- amlodipine
- affect the movement of calcium through calcium channels causing blood vessel relaxation, especially large vessels
- side effects/interaction: deem, avoid natural licorice, limit caffeine/alcohol, avoid grapefruit with felodipine
what si the contraindication associated with calcium channel blockers
heart failure
about beta blockers
- propanolol
- block adrenergic beta-receptors in the heart (B1) -> decrease rate and cardiac output
- prescribed fro treating heart problems
- side effects/interactions: dizziness, fatigue, bradycardia, hallucinations, avoid natural licorice
to whom are beta-blockers recommended for
not recommended as initial therapy in those over 60y
why is fasting glucose monitored when using beta-blockers
the symptoms experienced by beta-blockers could mask some symptoms of hypoglycaemia (dizziness, fatigue)
where is the drug metabolized and excreted
liver and kidney
with all HTN drug avoid ____
natural licorice because it contains glycyrrhinic acid
why should one consider the nutritional status of patient taking medication
low albumin may increase drug effect because of more free drug in the blood
which physiological status should be considered before medication use
pregnancy, lactation, presence of disease
when patient has diabetes, which drug do you prescribe
- with complications: ACEi or ARB
- without complications: ACEi ARB CCB or diuretics
when patient has coronary artery disease, which drug do you prescribe
ACEi or ARB
beta-blockers or CCB for stable angina
when patient has heart failure, which drug do you prescribe
ACEi or ARB + beta-blockers
AVOID CCB