Hypertension + Heart failure Flashcards

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1
Q

Define blood pressure

A

Force per unit area acting on vessels

Cyclical

MAP = CO X TPR

CO = SV X HR

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2
Q

What is the role of autocoids in blood pressure regulation?

A

Eg bradykinin, nitric oxide; act on vascular smooth muscle + endothelium

Acute BP maintenance working along with sympathetic NS + RAAS

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3
Q

Describe the relationship between the radius of a vessel and the resistance to flow

A

4th power relationship

Resistance to flow inversely proportional to vessel radius

Vasoconstriction- increased smooth muscle tone thus smaller lumen diameter - increased TPR- increased BP

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4
Q

Describe the pathophysiology and effects of hypertension (particularly on vasculature)

A
  • Vascular remodelling, hypertrophy, thickening
  • Hyperinsulinaemia and hyperglycaemia leading to endothelial dysfunction + ROS formation
  • Downregulation of NO signalling
  • Permanent hypertrophy of vasculature leading to increased TPR + reduced compliance

Increased morbidity + mortality

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5
Q

Give some examples of end organ damage due to hypertension

A
  • Renal disease
  • Peripheral vascular disease
  • Anueurysms
  • Vascular dementia
  • Retinal disease (retinopathy)

Hypertensive heart disease- left ventricular hypertrophy seceondary to increased afterload; dilated heart failure

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6
Q

Why is there a greater prevalence of hypertension in men?

A

Women have cardioportective effects pre-menopause from high oestrogen levels

Post-menopause, the risk of hypertension in women catches up to men

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7
Q

Despite hypertension often persenting asymptomatically, why is it necessary to treat?

A

To slow down/prevent progression of acute coronary syndromes, chronic heart disease, strokes

Reducing CVD risk

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8
Q

What is the NICE guideline for defining hypertension?

A

140/90 mmHg = hypertension

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9
Q

What are the main types of hypertension and which is most prevalent?

A

Primary/essential/idiopathic- most common

Secondary- phaeochromocytoma, thyroid disease

Pre-hypertensive state

Isolated systolic/diastolic hypertension

White coat/clinic hypertension

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10
Q

Describe the best practice for a clinical diagnosis of hypertension

A

Sitting, relaxed, arm supported

If there is a >15 mmHg difference between both arms, repeat measure + use arm with higher reading

ABPM/HBPM for white coat syndrome patients

CVD risk + end organ damage assessed

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11
Q

When may emergency treatment be required for hypertension ie what is considered a hypertensive emergency?

A

BP > 180/120 mmHg

+

Clinical signs eg papilloedema, retinal haemorrhage

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12
Q

What is the target BP for someone <80 yrs of age and for someone with T2DM? (ie at what BP should treatment be initiated?)

A

140/90

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13
Q

What is the target BP for someone >80 yrs of age? (ie at what BP should treatment be initiated?)

A

150/90

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14
Q

What is the target BP for someone with T1DM?

A

135/85 (lower if experiencing severe T1DM complications)

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15
Q

Define stage 1 hypertension

A

STAGE 1:

Clinic BP 140/90- 159/99

ABPM/HBPM 135/85 - 149/94

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16
Q

Define stage 2 hypertension

A

Clinic BP 160/100 - <180/120

ABPM/HBPM:

150/95 or higher

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17
Q

Define stage 3 (severe/resistant) hypertension

A

Clinic systolic <180

OR

Clinic diastolic > 120 mmHg

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18
Q

Define the BP ranges for pre-hypertension and give some lifestyle modifications to reduce CVD risk

A

>120/80 + <140/90 mmHg

Lifestyle advice

Reduced dietary sodium intake

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19
Q

List the main therapeutic agents used for primary hypertension

A
  • ACE inhibitors
  • Angiotensin (AT1) receptor blockers- ARBs
  • Calcium channel blockers- CCBs
  • Diuretics- thiazide, thiazide like

Targetting RAAS

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20
Q

Where is ACE found and what does it do?

A

Luminal surface of capillary endothelial cells, predominantly in LUNGS

Catalyses conversion of angiotensin 1 to POTENT VASOCONSTRICTOR angiotensin 2

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21
Q

In the presence of ACE inhibitors, how else can angiotensin 2 be produced from angiotensin 1?

A

Via chymases; angiotensin 2 production independent of ACE

22
Q

Give 2 examples of ACE inhibitors

A
  • Ramipril
  • Lisinopril
23
Q

Give some side effects of ACE inhibitors

A

Hypotension

Dry cough

Hyperkalaemia (low aldosterone)

Renal failure; renal artery stenosis where efferent arteriole constriction is required

Angioedema

24
Q

Give 2 examples of Angiotensin 2 receptor antagonists

A
  • Candesartan
  • Losartan
25
Q

Describe the action of CCBs

A

Target calcium initiated smooth muscle contraction

Interact with different sites on alpha 1 sub-unit of VOCC

Have a selectivity for vascular smooth muscle or the myocardium (pacing cells)

26
Q

Classify the calcium channel blockers into 3 types

A
  • Dihydropyridines - used for hypertension
  • Non-dihydropyridine: phenylalkylamines + benzothiazapines
27
Q

Which type of CCBs are selective for peripheral vasculature?

A

Dihydropyridines

Little inotropic/chronotropic effects; little effect on myocardium/pacing cells of heart

1st line CCBs for hypertension

28
Q

Which type of CCBs are selective for the myocardium + pacing cells of heart?

A

Non-digydropyridines; phenylalkylamines

Depresses SA + AV nodal conduction, negative inotropy (reduced force of contraction of heart)

29
Q

Which type of CCBs are selective to the myocardium and the vasculature?

A

Benzothiazapines (non-dihydropyridines)

30
Q

Give 3 examples of CCBs

A
  • Amlodipine
  • Nifedipine
  • Nimodipine (cerebral vasculature selectivity; sub-arachnoid haemorrhage)
31
Q

Give some side effects of the dihydropyridine class of CCBs (used for hypertension)

A

Ankle swelling

Flushing

Headache (vasodilation)

PALPITATIONS; REFLEX/COMPENSATORY TACHYCARDIA - thus contraindication with unstable angina, severe aortic stenosis

32
Q

Describe the drug interaction between amlodipine (CCB) and simvastatin

A

Amlodipine increases the effect of simvastatin, thus need to lower the dose of statins if taken with amlodipine

Also contraindications with other anti-hypertensives (eg hypotension)

33
Q

What is the main use of phenylalkylamines and how do they work?

A

Class 4 anti-arrhythmic (angina, hypertension)

Prolongs action potential + effective refractory period

Negative inotropic + chronotropic effects

34
Q

Give an example of a phenylalkylamine

A

Verapamil

35
Q

Give an example of a benzothiazapine

A

Diltiazem

36
Q

Give 2 examples of thiazide diuretics

A

Bendroflumethiazide

Indapamide

37
Q

What is the mechanism of action of thiazide diuretics?

Used for oedema

A

Inhibit Na+/Cl- co-transporter in DCT, thus increased Na+ and H20 EXCRETED

38
Q

Give some side effects and contraindications of thiazide diuretics

A
  • Hypokalaemia
  • Hyponatraemia
  • Hyperuricaemia
  • Arrhythmia (K+ disturbances)
  • Raised glucose
  • Raised cholestrol + triglyceride levels

Thus, contraindicated in hypokalaemia, hyponatraemia, gout, NSAIDS, K+ lowering drugs

39
Q

What is the 1st line medication for primary hypertension in patients with diabetes or those <55yrs age + not black?

A

ACE inhibitor or ARB

Then, add CCB, thiazide-like diuretic later if needed

40
Q

What is the 1st line medication for primary hypertension in a patient >55yrs age or black origin?

A

CCB; as they have low renin levels thus no point targetting RAAS

Then add ACEi/ARB, thiazide-like diuretic later if needed

(step 3 for all pt’s = ACEi OR ARB + CCB + thiazide-like diuretic)

41
Q

Why are ACE inhibitors always 1st line for primary hypertension in patients with diabetes? - regardless of their age/ethnicity

A

2 pronged approach

ACEi/ARB reduced risk of diabetic nephropathy + CKD with proteinuria due to dilation of efferent glomerular arteriole;

Reduced peripheral vascular resistance- reduced BP + DILATION of efferent glomerular arteriole– REDUCED INTRAGLOMERULAR PRESSURE- beneficial for T2DM

42
Q

What medication can be added at step 4 for resistant hypertension and what are some of its contraindications?

A
  • Spironolactone; aldosterone/mineralocorticoid receptor antagonist
  • Contraindicated in hyperkalaemia, Addison’s
  • Not with other drugs increasing K+ levels, ACEi’s, ARBs– monitoring needed

If patient is hyperkalaemic, consider adding SYMPATHETIC BLOCKERS- alpha/beta blockers, instead of spironolactone

43
Q

Give 3 examples of B-adrenoceptor blockers

A
  • Labetalol
  • Bisoprolol
  • Metoprolol
44
Q

Describe the mechanism of action of B-adrenoceptor blockers

A

Decrease sympathetic tone by blocking noradrenaline

Reducing myocardial contractility, thus decreasing CO

45
Q

Give an example of an alpha-adrenoceptor blocker

A

Doxazosin

46
Q

Describe the mechanism of action of alpha-adrenoceptor blockers

A

Selective antaagonist of alpha-1 adrenoceptors

Reduce peripheral vascular resistance, thus lower BP

(May lead to postural hypotension- dizziness, syncope, headache, fatigue)

Contraindicated in pre-existing postural hypotension, dihydropyridine CCBs- oedema)

47
Q

List some factors which can vary the cardiac output

A
  • Preload (filling pressure); LVEDP- sarcomere length - Starling’s curve
  • Afterload- load ventricle has to pump against
  • Contractility
  • Heart rate
48
Q

Give some symptoms of heart failure

A
  • Reduced exercise tolerance
  • Dyspnoea
  • Fatigue
  • Oedema- swelling; peripheral, pulmonary
49
Q

List some mangement options for heart failure; heart failure with reduced ejection fraction (<45%)

A
  • Diuretics (congestive symptoms + fluid retention); furosemide- loop diuretic
  • B-blockers; bisoprolol
  • ACEi’s; ramipril, lisinopril
  • Mineralocorticoid receptor antagonists; spironolactone
  • Angiotensin receptor blockers (ARBs); candesartan, losartan

AIM: reduce preload, reduce sympathetic stimulation, reduce blood volume– reduce workload on heart

50
Q

Why do you want to reduce sympathetic stimulation in heart failure by giving B-blockers?

A

To slow down heart rate and allow more time for contraction of the heart- with aim of increasing CO

51
Q

What is the usual type of heart failure?

A

LV systolic dysfunction; reduced LV ejection fraction <45%