LDL or low density lipoprotein carries it to the arteries and a high level of ldl means too much cholestrol going to the arteries and is bad while hdl high density lipoprotein carries it from the arteries to the liver for breakdown and so a high level of hdl (from excercise , weight loss and moderate alcohol ) is good. Reducing ldl cuts the risk of myocardial infarction - mi . Ldl if below 0.8 can lead to zero mi risk !.
Lipid profile blood test measures total cholestrol - tc , ldl , hdl , triglycerides in blood .
Evidence shows that reducing total cholestrol in the blood to 4 and ldl to 2 or by at least 30% and raising hdl to over 1 cuts the risk of heart attacks and strokes by 30 % . Non hdl (tc-hdl) should be less than 3 Babies have ldl of about 1 . Babbons and hunter gatherers have tc less than 3
Patients are asked about risk factors such smoking , diabetes , family history a first event in a first degree male relative under age 55 or female under 65 and a fasting blood test for lipids - total cholestrol tc , ldl , hdl , triglycerides , liver function tests , thyroid , glucose and hba1c . In oppurtunistic cases non fasting hdl and tc are done and if glucose is over 6.1 fasting glucose is ordered.
Its best to screen all patients over age 40. South Asian -sa- males have 46% higher death rate and 51% in females . So multiply their risk factor by 1.3 and by another 1.3 if triglycerides are over 1.7 . Tc/hdl more than 6 is high risk , as is high bp . Young patients with familial hyperlipidaemia should be referred .
90% of MIs can be predicted from risk factors such as abdominal obesity ie a waist size measured midway between bony points anterior superior iliac spine and lowest rib more than 90 cm in a male , and 80 in female . Let patient hold one end and walk round with the other . A bmi - height divided by weight in kg squared of over 25 means five times the diabetes risk as at bmi of 20 and at bmi 35 its 60 times .
An ldl of 4 causes risk of 20 events compared to 5 for an ldl of 2
Treatment is started at all ages if cvd risk factor is more than 20% or chd risk factor more than 15% over ten years - simvastatin 20mg . In trials a fall of ldl from 3 to 1.75 and rise in hdl from 1.1 to 1.3 caused a 10% regression in atheromas in 80% taking Rosuvastatin 40mg . However 40mg of any statin can cause liver problems and muscle aches and if alt rises by more than three times or ck by ten times , give statin holiday for one month , check them again and retry.
Also start treatment on all diabetics over age 40 and in diabetics age 18-39 if they have another risk factor eg fh , metabolic syndrome ,nephropathy, high bp , retinopathy etc.
Rosuva 10 and simva 40mg both reduce ldl by 40%.Check lipids lft and ck one month later . Double dose if target not achieved . Ezetrol reduces ldl by another 20%. Maxepa for high tgs . Fenofibrates can help . Niacin raises hdl but causes flushing .
S Asians have 20% diabetes compared to 1% for whites .Rosuvastatin should be started at 5mg , check lfts and ck before and one month after . If rises give a statin holiday and try again. CK is very sensistive and can rise four fold with minor trauma .Anyone with angina , send to rapid chest pain clinic and then ett and surgery . About half may present with sudden death. SA have 5.2 tc average and low hdl . Diabetics are considered to have had mi and must go straight to secondary prevention ie asprin , statin and acei, even at age 10 show signs of insulin resistance. I samosa is 26g of fat. Statins may not work as well in sa. Cholestrol is a solid fat and carried by ldl to arteries and by hdl back to lýver .
. start on statin for primary prevention if chd risk greater than 20 percent over ten years . Non hdl should be less than 3. Cholestrol is a vital component of cell structure and is the molecule used to make many hormones . However if excess cholestrol is made it circulates in the blood and some of it is taken up by the cells making up the walls of the coronary arteries and deposited there within and in between the cells . This is called an atheroma plaque and it eventually narrows the artery . During excercise not enough blood would flow to the heart muscle and there is angina ie chest pain located in the center and going up to the neck and left arm. Sometimes the plaque breaks through the inside wall of the artery and together with a blood clot which forms there , blocks all supply to the part of the heart it supplies and that part dies - ie a person has a heart attack . If too much of the heart dies , it wont be able to pump the blood and the person dies of heart faliure .
Heart attacks are the biggest killers of south asians in the west and so it is important to know how to lower dangerous cholestrol levels .
Fats are carried in the blood by three proteins called lipoproteins . The biggest one at 450 Angstrom units is VLDL protein and binds to triglycerides . The intermediate one is 200 A LDL and binds cholestrol in the blood and the smallest one at 60 A is HDL and it takes cholestrol from tissues to the liver to be destroyed . Moderate alcohol drinking and excercise can raise the HDL to over 1.3 and that is very good . A level less than 1.1 can be a big risk factor. A fasting blood sample for lipids will indicate the total cholestrol which should be less than 5 , the LDL cholestrol which should be less than 3.5 and the HDL which should be over 1.1 and the Triglyceride level which is a risk factor as well .
Cholestrol is taken up from the blood via receptors on the cell surface . If there is too little in the blood the cell will make its own via an enzyme called HMC co A . Drugs called statins block this enzyme and reduce the amount of cholestrol made and lead to about a 15% fall in the incidence of heart attacks and 30% of strokes. They also lower TG and increase HDL levels. Do not increase suicide or murder rates
One large heart protection study showed that antioxidant tablets were ineffective . In case antibiotics like erythormycin are to be used the statin should be stoped . Very rare is hepatotoxicity signified a three fold rise in ALT . Pravastatin does not interact with other drugs eg diltiazem.
Intially a fasting lipid profile is done and subsequently just the total cholestrol. An annual check by the doctor or nurse is recommended.The target is total cholestrol less than 5 or a 25% reduction , a LDL of less than 3.5 and HDL greater than 1.1. BP target is 140/85 and in diabetics 140/80 . Excercise to increase HDL and wt loss to get BMI below 25 . More fresh fruit and omega three in oily fish are useful. Aspirin 75mg dispersible is useful .
..updated oct 05 Lipids
Cholestrol is a compound which if it gets into the arterial vessel wall causes it to narrow and eventually block completely if a clot forms on top leading to death of muscle eg the heart area supplied by that artery. It is made in the liver 50% , then secreted into bile and absorbed via the gut 30% together with that eaten in the diet eg egg yellows . It is attached to ldl - a protein in the liver and in this form can get into the vessel walls . Another protein hdl takes it up from the vessels and takes it to the liver to be broken down. So it follows that too much cholestrol , too much ldl or too little hdl are all bad
QOF targets are total cholestrol of 5 or below in those with chd or cardiac risk factor > 20%, however other guidelines suggest that its better to have tc below 4 , ldl below 2 and hdl above 1.03 in men and 1.4 in women . Triglycerides should also be kept below 1.7
Before starting therapy encourage diet and exercise and check liver function tests and creatinine kinase levels. Get men to waist below 94cm . women below 80cm
Drugs which help to get to target are
Statins - these act on the enzyme Acetyl co-a in the liver , Simvastatin 10-40mg or Atorvastatin 10-20mg can cut ldl by 20-60 % and also cut tg a little and raise hdl a bit
However after 10mg , every doubling of the dose cuts ldl by only 6% and because acetyl coa is also made in the muscle , it affects the cell membrane and leads to muscle aches , so its better to cut statin dose back to 10mg and add ezetrol 10mg
Reduces intestinal absorption and in the drug ezetemibe combined with simvastatin and can give 50-60% reduction in ldl
Alcohol increases TG markedly and also increases risk of pancreatitis . Fish oil such as omacor 1-2g per day helps cut it . Also useful are fibrates
Alcohol does a little hence the protective effect of moderate drinking (21 units per week for men , 14 for women) . Nicotinamide helps but can cause hot flushes . Exercise raises hdl levels
Resins like cholestyramine are very rarely used as they cause flatulence
Diabetes +waist >94cm and any two of tg 1.7 , hdl 1.04 , bp 130/85 , fbs 5.6 . In ethnic minorities and those with family history of ischaemic heart disease treatment should be started early , even children may need treatment to stop atherosclerosis from developing.