Hypertension And Heart Failure Flashcards
What is blood pressure?
Blood pressure provides a driving force to defuse organs with blood - it determines the tissue perfusion pressure.
It is not uniform throughout the body and, as result of the cardiac cycle, is cyclical.
What is mean arterial pressure equal to?
MAP = CO X TPT
What is CO equal to?
CO = SV x HR
Describe the relationship between resistance and increased maBP
Smooth muscle tome changes TPR.
Vasoconstriction causes an increase in TPR and therefore an increase in BP.
Why does elevated BP cause an increase in morbidity and mortality?
Leads to vascular changes inc. remodelling and thickening and hypertrophy.
Increase vasoactive substances inc. ET-1, NAD, angII
Vascular remodelling as direct result of local salt sensitivity
Hyperinsulinemia and hyperglycaemia - endothelial dysfunction and ROS cause decreased NO. Resulting in permanent and maintained medial hypertrophy of vasculature causing increased TPR and decreased compliance.
End organ damage (renal, peripheral vascular disease, aneurysm, vascular dementia, retinal disease)
LVH - dilated cardiac failure
All causing increasing morbidity and mortality.
Why is the incidence of hypertension lower in women?
As they are protected until menopause (not sure why)
Why do you treat HT even when it presents asymptoatically?
Because the risk of CHD and stroke increases.
Define Hypertension
An elevation in blood pressure that is associated with an increase in risk of harm. .
What level of BP defines hypertension?
Over 140/90
How do you diagnose and treat HT?
Screen those at risk
Increase public awareness of risk factors.
Reliable diagnoses based on clinical guidelines.
Promote appropriate lifestyle changes to limit risk - no immediate gain.
Regular monitoring and refinement of medication.
What is the best practise for clinically diagnosing BP?
Measure BP while patient is sitting, relaxed and arm is supported.
Measure in both arms and if there is >20mmHg difference then repeat and use higher reading.
What is stage 1 hypertension?
> 140/90 mmHg
What is stage 2 hypertension?
> 160/100 mmHg
What is severe hypertension?
> 180 mmHg systolic or > 100 mmgHg diastolic
How does diabetes and renal change BP criteria?
Stage 1 = > 130/80
What is prehypertension?
Elevated BP below stage 1 diagnoses with no end organ damage.
What do you recommend for people in a prehypetensive stage?
Lifestyle changes:
Regular exercise
Healthy / balanced diet
Reduce stress and relaxation
Limit / reduce alcohol intake
Discourage excessive caffeine consumption
Smoking cessation
Reduction in dietary sodium
What are the primary HT therapeutic agents?
Angiotensin converting enzyme (ACE) inhibitors
Angiotensin (AT1) receptor blockers (ARBs)
Calcium channel blockers (CCBs)
Diuretics
Others in specific circumstances
How does ACE work?
ACE is present on the luminal surface of capillary endothelial cells, predominantly in the lungs.
ACE catalyses the conversion of Ang-I to Ang-II, a potent active vasoconstrictor.
Ang-II works through AT1 and AT2 receptors.
How do ACE inhibitors work?
Limit conversion of AngI-AngII by inhibiting circulating and tissue ACE
So: Vasodilation Reduced aldosterone release Reduced ADH release Reduced cell growth and proliferation
All can contribute to antihypertensive effects.
Give exampleof ACE inhibitors
Ramipril
Lisinopril
Enalapril
Captopril
What are some common side effects of ACE inhibitors?
Dry cough (bradykinin)
Angiodema (more common in black people)
Renal failure (inc. renal artery stenosis)
Hyperkalaemia
What is losartan?
An ARB (angiotensin receptor blocker)
Describe how ARBs work
They directly target AT1 receptors so are more effective than ACEi at inhibiting Ang-II mediated vasoconstriction.
Why no cough on ARBs?
As don’t make bradykinin because directly act onAT1 receptor. But, means less effective in low-renin hypertensives.