Unit 6 - Cardiovascular system 7 Flashcards
Where is the majority of cholesterol produced?
Liver
- contribution from diet
What is cholesterol essential for?
Cell membrane integrity Precursor in production of - steroid hormones - bile acids - vitamin D
What can lead to an atherosclerotic plaque?
LDL-C susceptible to oxidation at damaged endothelium
Why is HDL called “good cholesterol”?
HDL-C carrier of cholesterol away from circulation to liver for recycling
it helps remove other forms of cholesterol from your bloodstream
What is cholesterol screening?
Part of CVD screening and used in predicting 10 year CVD risk - utilisation of QRISK Capillary (pin prick) test - total - HDL cholesterol - non-fasting Venous test - total - HDL-C - non-HDL-C - triglycerides
What other tests can be used to assess risk of CVD?
Renal function
Liver function
Thyroid stimulating hormone
Blood pressure
What are statins?
Competitive inhibitors of HMG-CoA reductase
- rate controlling enzyme in mevalonate pathway
- affect production of cholesterol
- increases LDL receptor expression
What are statins used for?
Improve endothelial function
Modulate inflammatory response
Maintain plaque stability
Prevent thrombus formation
Which statin is used for primary prevention?
20 mg Atorvastatin once daily
(10 year CVD risk > 10% using QRISK)
- 40% reduction in non HDL-C at 3 months
What dose is used for secondary prevention?
80 mg Atorvastatin one daily
Which cholesterol medication is contraindicated in pregnancy?
Statins
What are the side effects of statins?
Pain
Tenderness or weakness in muscles
- measure creatinine kinase levels
- explore other possibilities of symptoms
What effect does grapefruit juice have on statins?
Interferes with first pass metabolism of statins
- elevates levels of active drug
What are the treatment aims of chronic stable angina?
- Stop or minimise symptoms
- To improve quality of life and long term morbidity
- increase exercise tolerance by getting better perfusion of the heart and decreasing demand - Reduce the risk of a major cardiovascular event
- plaque rupture and thrombus formation
- MI
How can acute attacks of chronic stable angina be managed?
Short acting sublingual nitrate therapy
- glyceryl trinitrate (GTN) tablets or buccal spray
- nitrolingual
- glytrin
- nitromin
When should the emergency services be called when using GTN spray?
Rapid pain relief
- if not gone, repeat dose after 5 mins
- if pain persists, call emergency services
When can GTN spray be used?
Before exercise or exertion
How does GTN spray work?
Mechanism is principally rapid venodilation and reduction in cardiac preload
- reduced cardiac work / O2 demand
What is the long term management of chronic stable angina?
All patients should receive treatment with drugs which reduce cardiac O2 demand in the longer term
- minimises the frequency of acute attacks
Selection will depend of LV function and how well tolerated
- caution if LV systolic dysfunction or congestive heart failure
What is step 1 of long term management of chronic stable angina?
Either beta-adrenoceptor antagonist (beta-blocker) OR rate limiting Ca2+ channel blocker (CCB)
- depending on tolerance / preference
If LV dysfunction DO NOT USE verapamil
What is step 2 of long term management of chronic stable angina?
If inadequate response in step 1, consider switching or using a combination of the two
What are the options if no adequate response to beta blockers or Ca2+ channel blockers when managing chronic stable angina?
Long acting nitrate OR Ivabradine OR Nicorandil OR Ranolazine
What causes chronic stable angina?
Coronary blood flow is limited during systole
- extravascular compression
- coronary arteries blocked off by the aortic valve
Maximise time in diastole to increase perfusion by reducing heart rate
How do beta blockers treat chronic stable angina?
- reduce heart rate
- reduce contractility
- reduce arterial pressure (afterload)
- reduces the oxygen demand of the heart
