Hypertension And Heart Failure

Question 1

What is blood pressure?

Answer 1

Driving force to perfuse organs with blood (force per unit area acting on vessels)

Question 2

How to calculate resistance to flow

Answer 2

(8Xviscosity) X length / pie radius4 (to the power) = resistance to flow

Question 3

Define hypertension, what are the three categories of causes?

Answer 3

An elevation in blood pressure associated with an increase risk of some harm

140/90 mmHg

Essential/ primary/ idiopathic (90%) 
Secondary to other pathology 
Pre- hypertensive 
Isolated systolic/ diastolic 
White coat/ clinic

Question 4

Best practice for recording blood pressure

Answer 4

Sitting
Relaxed
Arm supported

Both arms >15mmHg difference repeat measurement and use arm with higher reading
Measurements over period of visits +/- ABPM/ HBPM

Emergency treatment required >180/ 120 + clinical signs

CVD risk and end organ damage should be assessed whilst waiting for hypertensive conformation

Question 5

What are the blood pressure boundaries for diagnosing hypertension?

Answer 5

140/90 <80yrs
150/90 >80yrs
135/85 type 1 diabetes

Offer treatment
Target aim: 120/80 mmHg

Question 6

What blood pressure categories hypertension as stage 1, 2 or 3/ severe?

Answer 6

Stage 1: clinic 140/90 - 159/99 mmHg
and subsequent ABPM daytime average or HBPM average 135/85 - 149/94 mmHg

Stage 2: clinic 160/100 mmHg or higher
And subsequent ABPM daytime average or HBpM average of 150/95 mmHg or higher

Stage 3/ severe: clinic systolic 180mmHg/ higher or diastolic 120mmHg/ higher

Question 7

What categorises someone as prehypertension? How can you reduce their risk?

Answer 7

> 120/80 <140/90 mmHg

✅promotion regular exercise, modified healthy/ balanced diet, reduction in stress and increased relaxation, limited/ reduced alcohol intake, discourage Xs caffeine, smoking cessation, reduction dietary sodium

= CVD risk reduction

Question 8

List the main primary hypertension therapeutic agents

Answer 8

Angiotensin converting enzyme inhibitors (ACEi)

Angiotensin (AT1) receptor blockers (ARBs)

Calcium channel blockers (CCBs)

Diuretics- thiazides and thiazides like

Other agents

Question 9

Where is ACE found? How does angiotensin-2 cause its actions?

Answer 9

ACE - luminal surface of capillary endothelial cells predominantly in lungs

Catalysed conversion angiotensin 1 to angiotensin 2 vasoconstrictor

Angiotensin 2 binds to AT1 and AT2 receptors

AT1 - receptor subtype typical of classic angiotensin 2 actions (vasoconstriction, stimulations of aldosterone, cardiac and vascular muscle cell growth and vasopressin release from PP)

Question 10

Why is there still some angiotensin 2 produced even with a high dose of ACEi?

Answer 10

Angiotensin 2 also produced from angiotensin 1 independently of ACE via chymases

Question 11

What are the side effects of ACEi, explain why you get some of them? When shouldn’t you use ACEi? Give an example of one

Answer 11

Dry cough - build up of bradykinin (also substrate for ACE)

Hypotension - vasodilation by stopping production of angiotensin 2 and also from build up bradykinin (vasodilator via NOS/NO and PGI2)

Hyperkalaemia (low aldosterone)

Angioedema (more common black ppl)

Renal failure (renal artery stenosis where construction of efferent arteriole needed)

❌if person has renal artery stenosis, AKD, pregnant, breastfeeding
Be careful if: on drugs increase K, NSAIDs, other antihylertenisve agents

E.g. ramipril, lisinopril

Question 12

Angiotensin 2 receptor blockers/ antagonists (ARBs): benefits, drawbacks, when to avoid, when to be cautious, examples

Answer 12

AT1 and AT2 receptors

No effect bradykinin ✅
Reduced angioedema✅

Less effective in low-renin hypertensives❌

directly target AT1 more effective at inhibiting Ang2 mediated vasoconstriction (chymase production too)

When to avoid: renal artery stenosis, AKD, pregnancy, breastfeeding

Be cautious: other K increasing drugs, NSAIDs, other antihypertensive agents

Candesartan or losartan

Question 13

How do Calcium channel blockers work?

Answer 13

L-type calcium channels allow inward Ca flux (VOCC) expressed throughout body e.g. vascular smooth muscle cells, cardiac myocytes, SA and AV node

Calcium channel blockers target calcium initiated smooth muscle contraction (in hypertension) - 3 types interact with different sites on alpha-1 subunit of VOCC (selectivity for vascular smooth muscle or myocardium)

Question 14

What are the 3 classes of Calcium channel blockers? Compare them briefly

Answer 14

• dihydropyridine
  Selective for peripheral vasculature, little chronotropic or inotropic effects (first line CCB for hypertension) cerebral vs peripheral selectivity

Non-hydropyridines:

• phenyalkylamines
  Depresses SA node and slows AV conduction, negative inotropy
• benzothiazpines sit in middle

Question 15

When are calcium channel blockers the first choice for antihypertenisve treatment?

Answer 15

In low renin patients

Question 16

Compare different drugs in the dihydropyridine class. What do they do? Side effects, when are they unsuitable, drug reactions?

Answer 16

Amlodipine - longer half life
Nimodipine - selectivity for cerebral vasculature (sub arachnoid haemorrhage)

Selective for peripheral vasculature, little chronotropic or inotropic effects (first line CCB for hypertension) cerebral vs peripheral selectivity

❌ankle swelling, flushing, headaches (vasodilation), palpitations (compensatory tachycardia reflex)

Unsuitable: unstable angina, severe aortic stenosis

Drug reactions: amlodipine + simvastatin (increased effect of statin), other antihypertensive agents

Question 17

How do phenylalkyamines work, example, uses, side effects, contraindications, drug interactions?

Answer 17

Class 4 anti-arrhythmic agent/ prolongs action potential/ effective refractory period

E.g. VERAPAMIL

Less peripheral vasodilation, negative chronotropic and inotropic effects

Used for: arrhythmia, angina, hypertension

❌constipation, bradycardia (I.v.), heart block, cardiac failure

Contraindicated: poor LV function (caution needed), AV nodal conduction delay

Interactions: beta blockers, other antihypertensive and antiarrhythmic agents

Question 18

Example of a benzodiazepine

Answer 18

DILTIAZEM

Sit between other CCB classes

Question 19

How do thiazides and thiazides-like diuretics work? Give examples. Side effects, contraindications, drug interactions

Answer 19

Inhibit Na/ CL co-transporter in DCT
Long term effects mediated by sensitivity of vascular smooth muscle to vasoconstrictors Ca/ Na

E.g. BENDROFLUMETHIAZIDE, Inadapamide (thiazides like)

❌hypokalaemia, hyponatraemia, hyperuricemia, Arrhythmia, increased glucose/ cholesterol/ triglyceride

Contraindicated: hypokalaemia, hyponatraemia, gout

Interactions: NSAIDs, K lowering drugs (monitoring)

Question 20

Describe the steps to treatment of primary hypertension

Answer 20

Hypertension with type 2 diabetes or hypertension age <55 and not black Africans or African Caribbean-> ACEi / ARB -> + CCB / thiazide-like diuretic -> 3: ACEi / ARB + CCB + TLD -> 4: confirm resistant hypertension, discuss adherence, expert advice or add: low dose spironolactone if blood K 4.5

Hypertension >55yrs or black African or African Caribbean family origin -> CCB -> + ACEi / TLD -> steps 3 and 4 as above

Question 21

When are diuretics used over CCBs?

Answer 21

In oedema

Question 22

When do you need to seek expert advice in regards to antihypertensive medication?

Answer 22

If Bp is uncontrolled on optimal tolerated doses of 4 drugs

Question 23

How do you treat resistant hypertension and what is it? Contraindications, drug interactions, when might you use a different treatment?

Answer 23

If BP not controlled after step 3 e.g. after ACEi / ARB + CCB + TLD

First thing to consider is:
SPIRONOLACTONE- aldosterone receptor antagonist

Not if: hyperkalaemia, Addison’s
Interactions: K+ increasing drugs e.g. ACEi and ARBs (monitoring)

Can give alpha and beta blockers if high K

Centrally acting drugs - labetalol (pregnancy, IV hypertensive emergencies) reduced sympathetic outflow

Question 24

How do beta adrenoceptor blockers work? Give examples, side effects, contraindications, drug interactions

Answer 24

Decreased sympathetic tone by blocking NAd and reducing myocardial contraction, decreases renin secretion

E.g. LABETALOL, bisoprolol, metoprolol

❌ bronchospasm, heart block, Raynaud’s, lethargy, impotence 
Mask tachycardia (sign of insulin induced hypoglycaemia) 

Contraindications: asthma, COPD, haemodynamic instability, hepatic failure (dose monitoring)
Drug interactions: non- dihydropyridine CCB - verapamil and diltiazem -> asytole

Question 25

How do alpha adrenoceptor blockers work, example, side effects, contraindications, drug interaction

Answer 25

Selective antagonism of alpha 1 adrenoceptors, reduce peripheral vascular resistance

E.g. DOXAZOSIN

❌postural hypotension, dizziness, syncope, headache, fatigue

Don’t give if already have postural hypotension
- dihydropyridine CCBs

Question 26

Definition of heart failure, symptoms

Answer 26

Abnormality in cardiac function which is responsible for the failure of the heart to pump blood at a rate commensurate with the requirements of metabolising tissues

Characterised by symptoms that may present and often in later stages - exercise intolerance, dyspnoea, fatigue, swelling

Question 27

How does physiological response to reduced cardiac output sometimes lead to further pathology?

Answer 27

Cardiac output reduction detected
Neurohormonal response (sympathetic NS and RaAS)
Vasoconstriction
Increased preload and afterload
Increased cardiac workload
Ventricular dilation and remodelling (proliferating signalling) - increased myocardial O2 demand

Question 28

Management of heart failure pathway

Answer 28

Chronic heart failure diagnosed -> diuretics (furosemide)

With preserved ejection fraction -> manage comorbidities, personalised exercise based cardiac rehabilitation programme unless unstable

With reduced ejection fraction -> offer *ACEi (lisinopril) and BB (bisoprolol) and MRA (spironolactone) if symptoms continue -> personalised exercise programme
*consider ARB (candersartan) if into,errant to ACEi