Let us talk more about the heart

by Dr. Maswoodur Rahman Prince

In the last instalment we talked about coronary artery disease and related issues. In this instalment we will talk about some leftovers and about lipids, food and drinks in relation to coronary artery diseases.

Successful thrombolysis does not mean that a heart attack is averted for ever: It is to be remembered that thrombolysis is a stop-gap treatment of heart attack only. This should be followed by an assessment of the severity of the obstruction in the coronary artery. If severe, enough, these obstructions should be treated accordingly by either angioplasty (ballooning), angioplasty with stenting or by bypass surgery (PTCA, PTCA with stenting or CABG).

What are the chances of recovery from heart attack? With improved treatment available now-a-days, about 90 per cent victims of heart attack recover. However, the quality of life after surviving a heart attack depends to a large extent, on preservation of heart muscles, which can only be achieved by thrombolysis within the golden hour and appropriate treatment (revascularisation) afterwards.

When is CABG needed? The primary indication of Coronary Artery Bypass Grafting (CABG) is angina pectoris, which is so severe that it does not respond to medical treatment. It is also indicated in severe obstruction of all major coronary arteries, associated with heart muscle damage. CABG may be life saving in obstruction of the left main coronary artery, as its complete blockage is actually fatal.

What is CABG? Coronary Artery Bypass Grafting (CABG) surgery is what is generally known as open heart surgery. In fact bypass surgery does not eliminate the blockage or address the underlying disease process. It creates a detour to reroute the blood around the blockage, using blood vessels from other parts of the body.

Because most occlusions occur in the first centimetre or two of the major arteries feeding the heart and only rarely affect smaller branches, the surgeon is able to directly manoeuvre around the area of blockage. Generally a blood vessel is taken from the chest or leg. It is attached at one end to the aorta and grafted at the other end onto the coronary artery below the blockage. The new segment allows sufficient blood to flow to nourish the heart muscle once again.

Who pioneered CABG surgery? During the 1960s, Dr. Rene Favaloro, a surgeon at the Cleveland Clinic, USA, pioneered CABG surgery. By the mid-1970 CABG surgery became widely accepted as a fruitful treatment for CAD. Today CABG surgery is performed routinely and safely at many hospitals and cardiac centres throughout the world.

What is PTCA (angioplasty)? The term angioplasty or balloon dilatation is synonymous with percutanceous transluminal coronary angioplasty (PTCA). The term angioplasty comes from the Latin "angio" meaning blood vessel and "plasty" meaning to "mold or shape". Medically referred to as PTCA, angioplasty is a group of invasive techniques used to reshape the inside of the coronary arteries. The procedure does not require surgical operation. It is performed during cardiac catheterisation. Basically, the procedure consists of positioning of a balloon mounted on a heart catheter across a coronary obstruction. The balloon is inflated to dilate the coronary artery at the site of narrowing, which increases the lumen of the artery. PTCA is most effective when arterial narrowing is present at a single site, involving a short segment of a major coronary artery. Results of multi-vessel PTCA are generally disappointing, and CABG is often needed in the future.

Who did the first cardiac catheterisation? Cardiac catheterisation for either diagnosis or treatment would not be possible without the contribution of Dr. Mason Sones, a cardiologist at the Cleveland Clinic. In 1958, Dr. Sones was inadvertently responsible for the first selective coronary angiogram. While performing an aortogram (a procedure in which X-ray pictures are taken of the aorta following an injection) on a 26-year-old patient suffering from rheumatic heart disease, he accidentally injected contrast dye into the right coronary artery. The patient suffered no ill effects, and Dr. Sones recognised the benefits of creating clear, detailed pictures of the coronary circulation. Based on this discovery, he designed catheters and developed techniques to X-ray the various coronary arteries. Out of this accident arose the knowledge that would change cardiology and that paved the way for further advances in documenting coronary artery blockages.Coronary Artery Disease Risk Factors:

(A) Factors that cannot be modified:-(1) Family history(2) Age(3) Male gender(B) Factors that can be improved(1) Smoking(2) Abnormal blood cholesterol(3) Hypertension(4) Lack of exercise(5) Diabetes(6) Obesity(7) Mental (psychological) factors.

Why family history is taken to be number one risk factor? Coronary artery disease "runs in families". Research and recent studies have marked family history as the number one non-modifiable risk factor. It is to be remembered that families share lifestyle traits every bit as much as they share genes. Families eat together; some exercise together; smokers often pick up the habit from a parent or sibling; even non-smokers are at increased cardiac risk from passive smoke exposure if anyone in their household smokes. Stress, too, is a cardiac risk that tends to be shared among family members. In addition to these acquired habits, some cardiac risk factors can be inherited; high cholesterol levels, hypertension, diabetes, and even obesity can have a genetic basis. Families with these traits do share an increased risk of coronary artery disease. "If your family tree includes branches felled by heart attacks, you should take extra care to prune your risks. Be sure, too, that your medical care includes tests for cholesterol, hypertension, and diabetes."

What is cholesterol? Cholesterol is not a fat. Instead it is a fat-like substance of soft and waxy consistency. If is an integral component of animal cell membranes and a precursor of bile acids and several hormones. It is held in a complex form with proteins in the circulating blood. Where is the cholesterol in food? Remember that cholesterol is a vital constituent of all animal cells. Vegetable cells, on the other hand, get along, perfectly well without any cholesterol. Cholesterol are found only in foods from animal sources; all vegetable foods are cholesterol free. If intake of animal fat is reduced, intake of cholesterol is automatically reduced. However, to fight atherosclerosis, it is important to eat foods low in both cholesterol and fat, particularly saturated fat. Particularly one should avoid eating saturated fats from vegetable sources to lower LDL cholesterol or bad cholesterol.

What is Lipid? Lipid is a broad term for chemicals that are insoluble or poorly soluble in water and serve as metabolic fuels, components of cell membranes or precursors of hormones. Cholesterol and triglycerides are two familiar varieties of lipids.

What is Lipoprotein and Lipid profile? Lipoprotein is a fat protein complex, that carries cholesterol triglycerides and related substances in the blood. Lipid profile is a blood test in which the blood levels of cholesterol, its fractions and triglycerides are measured.

What is Low Density Lipoprotein (LDL), High (HDL) Density Lipoprotein and Triglyceride? LDL is the major carriers of cholesterol in the blood. A high level of LDL promotes atherosclerosis and coronary heart disease. Very Low Density Lipoprotein (VLDL) is the major carrier of triglyceride in the blood in fasting state. VLDL forms in the liver. VLDL also contains cholesterol. After shedding off its triglycerides, the VLDL is converted into LDL. HDL is a blood lipoprotein that carries 20-25 per cent of the cholesterol in blood. HDL removes cholesterol from the surface of cells and transfers it to other lipoproteins for processing in the liver. It is called "good cholesterol" because high levels of HDL are associated with a lower risk of coronary heart disease.

Triglycerides or fatty acid: Fatty acid breakdown product of fats (triglycerides) consist of a chain of carbon atones whose length and degree of saturation can vary. A fat molecule consists of one glycerol (glycerine) molecule and 3 molecules of fatty acids, hence the term triglyceride.

What are the cholesterol rich food?: As told earlier cholesterol is found only in animal foods. Most of the animal foods are rich in both cholesterol and saturated fat. Some like egg yolk, liver, brain, kidney and sweetbread which are especially rich in cholesterol but their fact content is not so high. Fish is low in fat and cholesterol.

What are the foods your heart likes best? Foods that can save arteries and prevent heart disease are seafoods especially sea fish, fruits, vegetables, nuts, high fibre foods, grains, legumes, onions, garlics, olive oil, alcohol in moderation, foods high in Vitamin C, E and Beta Carotine (micronutrients).

Why fish is good for heart? Eating fish, particularly fatty fish, overflowing with omega 3 fatty acids prevents heart disease. Fish provides high class protein, calcium, omega 3 fatty acid, polyunsaturated fatty acid (PUFA) and other nutrients. Saturated fat and cholesterol content of most fish is also low. Regular consumption of fish reduces the risk of death from coronary heart disease.

Vegetables the source of dietary fibres: Dietary fibre is the indigestible carbohydrate in our diet, derived from plant foods. The sources of dietary fibres are vegetables, fruit peel, and outer coating of unlined grains. These are insoluble fibres. Rich sources of soluble fibre are barley, oats, gram, soyabean, peas, guava, pomegranate, grapes and apples.

How does dietary fibres reduce blood cholesterol? Liver is the chief site of cholesterol synthesis. A part of cholesterol synthesised by the liver gets incorporated into bile acids and bile salts. Bile is secreted in the gut to help digestion and absorption of food. It is reabsorbed and taken up by the liver after digestion of food. Dietary fibre interrupts this cycle by preventing reabsorption of bile salts from the gut. The later are excreted with undigested food.

Are nuts helpful for heart patients? Nuts like almonds, cashew nuts, groundnuts and walnuts are all right. Most of the fat present in nuts is unsaturated. Nuts are also devoid of cholesterol. However too much nut is not advisable for obese people due to their high fat content.

Role of garlic: Eating garlic regularly can deter artery clogging, and more remarkably, even reverse the damage, helping heal arteries. Worldwide, eating garlic is linked to less heart disease.

Why to avoid excessive sugar intake? Too much of sugar promotes undesirable weight gain and tends to increase blood triglyceride level.

Why to take olive oil? "In the Mediterranean diet olive oil is a major source of energy, fat averages 35 to 40 per cent of total calories, and rates of coronary disease are as low as in populations with low-fat diets." What makes monounsaturated fat, dominant in olive oil, better for the heart? Chemically, it is simply nicer to arteries. It lowers bad LDL cholesterol, but not good HDL cholesterol. Additionally, monounsaturated fat has antioxidant activity that fends off artery damage from LDL cholesterol.

Does alcohol intake protect against CHD? Some studies have shown that regular alcohol consumption in moderate amount may reduce the risk of death from fatal heart attacks. Social drinkers may continue drinking in moderation. However alcohol in excess of 60ml of whiskey/rum, 180ml of wine or 360ml of bear should be avoided. Excessive consumption of alcohol may raise blood triglyceride levels and weight.

Source: The Daily Independent, Dhaka, December 24, 2001