Hypertension and Heart Failure Flashcards
How do you calculate MAP?
MAP = CO x TPR
(CO= SV x HR)
What are the 2 key drivers to increase blood pressure when blood pressure drops?
Increased sympathetic activity and activation of RAAS
What end organ damage can result from hypetension?
- Renal
- Peripheral Vascular Resistance
- Aneurysm
- Vascular Dementia
- Retinal Disease
- Hypertensive heart disease → LVH causing cardiac failure
Why treat hypertension if it asymptomatic?
Early management slows down/ prevents progression to CVD
What is the NICE definition of hypertension?
Hypertension = 140/ 90 mmHg
(>40% of UK population)
What are the 2 main types of hypertension and what are their respective incidences?
1) Essential/ primary/ idiopathic - 90%
2) Secondary - related to other pathology (disease/ tumours)
What is the white coat/ clinic effect?
Elevated blood pressure when measured in the clinic vs a home
What is best practice for measuring BP?
- Measure with patient sitting, arm supported and relaxed
- Measure both arms - >15 mmHg difference repeat the measurement and use arm with highest reading
- +/- ABPM / HBPM
what blood pressure would be considered a hypertensive emergency?
> 180 /120 mmHg
Define the stages of hypertension
Stage 1: 140/90 mmHg - 159/99 mmHg
Stage 2: 160/100 mmHg >
Stage 3: systolic blood pressure of 180mmHg or higher or diastolic 120mmHg or higher
What BP is defined as pre-hypertension?
>120/80 but <140/90 mmHg
What advice would you give to someone who is pre-hypertensive?
- Promote regular exercise
- Modified healthy/ balance diet
- Reduction in stress and increased relaxation
- Limit/ reduce alcohol intake
- Discourage excessive caffeine consumption
- Smoking cessation
- Reduce dietary NaCl
What are the main actions of Angiotensin II?
- Increase sympathetic activity
- Tubular Na+/ Cl- reabsorption and K+ excretion → H2O retention
- Aldosterone secretion from the adrenal gland
- Increase arteriolar vasoconstriction
- ADH secretion from pituitary → H2O absorption
Which receptor type does Angiotension II primarily exert its actions via?
AT1
(There are AT1 and AT2 receptors)
How does a reduction in Angiotensin II effects cause a reduced BP?
- vasodilation
- reduction in aldosterone release → increased Na+ and H2O excretion
- reduced ADH release → increased H2O excretion
- reduced cell growth and proliferation (vascular smooth muscle)
How is Angiotension II produced independently of ACE?
Chymases can convert angiotensin I → angiontensin II
What are the 2 major ACEi?
Lisinopril
Ramipril
What are the main side effects of ACEi?
- hypotension
- Dry cough
- Hyperkalaemia (low aldosterone increases K+)
- Renal failure (esp. in renal artery stenosis)
- Angiodema (more common in black population)
Why do ACEi cause dry cough?
Bradykinin is a substrate for ACE too
Inhibiting ACE therefore builds up bradykinin which causes cough and vasodilation by NOS/NO and PGI2
In which patients are ACEi contraindicated in?
- Renal Artery Stenosis
- AKD
- Pregnancy
- Breastfeeding
- CKD
In which patients should ACEi be prescribed with caution?
- Other drugs that increase K+
- NSAIDs
- Other anti-hypertensives
Which receptor to Angiotensin II receptor blockers (ARBs) target?
AT1 receptor
More effective at inhibiting Ang II mediation vasoconstriction via chymase production
What are the 2 major ARBs used to treat hypertension?
Candesartan
Losartan
What are the benefits of ARBs over ACEi?
No effect on bradykinin so no dry cough and less angiodema
In which patients are ARBs contraindicated in?
- Renal artery stenosis
- AKD
- Pregnancy
- Breastfeeding
- CKD