Cholesterol elevation in your blood is bad for you.
How high is too high, and how low is too low?
- Too low? I think not. The lower the better. At birth LDL is about 0.4 mmol/l.
- Too high?
- LDL>3.5 on statins after a vascular event means you may need subcutaneous (SC) injections of more powerful drugs.
- LDL >5 with a family history, and again you will need the SC injections even if you have not had a cardiovascular event- prevention is better than cure.
- What if the LDL is already “good” at <2 mmol/l, but coronary disease is progressing? There is some data to measure Lp(a), and if >50mg/dl, then risk is increased.
So, the target is really an LDL<2, total cholesterol <4, a ratio of TC:HDL <4 as the bare minimum when you have had a heart attack, or non HDL cholesterol <3.8.
How to I persuade a patient who is reluctant?
I look for established hardening of the arteries – atherosclerosis:
- USS carotid – looking at intimal hyperplasia- early hardening- no radiation exposure, but not as good as CT
- CT calcium score – it that is high, then people will usually listen to medical advice. The radiation dose is low nowadays.
What are the choices?
It is all about lipid lowering. However you do it, whether drugs or diets, 1mmol/l reduction reduces your risk by the same amount.
- Diets – They lower LDL by 0.2-.04 mmol/l-not enough
- Statins – These are the most evidence based- can lower your LDL by 1/3.
- PSK-9 inhibitors (Alirocumab (Praluent) at 75mg every 2 weeks or 150mg every 2 weeks; or Evolucumab 140mg every 2 weeks – Proven to reduce LDL on top of statins
- Bempedoic acid
Who should we screen for Familial Hyperlipidaemia?
- LDL >4.9, Total cholesterol >7.8
- Family history of premature Coronary disease
- Personal history of MI <55 in men, or 60 in women.