Coronary Artery Disease

written by Dr Suren Thuraisingham on 15 August 2011


Whose Heart Next ?
The heart is like an engine. For efficient function, it needs strong cylinders (left and right ventricles), good fuel supply through clean fuel pipes (blood flow through the 3 main coronary arteries), good spark plugs (pacemaker) and valves (4 in the heart). 
The commonest heart problem and also the commonest cause of death (50%) worldwide, is coronary artery disease (CAD). Narrowing and blockage (atherosclerosis) of these fuel pipes may occur gradually (stable angina) or suddenly (unstable angina or myocardial infarction – heart attack). 
Stable angina occurs when the gradual build up of plaque produces a solid and usually firm narrowing (>60%) of the artery leading to a shortage in flow of blood (ischaemia) to the needy heart muscle that is being supplied by that particular artery. 
Angina is usually an exertion or stress induced chest squeezing or pressure especially when climbing slopes / stairs and may involve the throat and the arms. It may be worse after meals. It is relieved by rest within 3-4 minutes. Some individuals, especially diabetics, may only feel breathlessness without pain. Thus any significant change in exercise tolerance should raise concerns about stable angina.
Severe crushing central chest pain which may spread into the jaw or arms occurring at rest with sweating and breathlessness are the classical features of a heart attack (myocardial infarct). However, about 40% of individuals may present with much milder symptoms and even with no symptoms at all- although that is rare. Hence if you are an “AT RISK” individual (see below for definition) with a new chest symptom that is unexplained, seek medical attention immediately.
The cause of heart attack is usually the rupture of a mild, soft and therefore more fragile plaque before it has produced any significant narrowing. It resembles a ‘pimple’ bursting into the blood channel exposing its nasty contents to the passing blood which then provokes the formation of a clot. The clot may progress to block the vessel and stop blood supply to the heart muscle which then leads to muscle death. As many as 40% of people who suffer heart attacks or sudden cardiac death have no warning heart symptoms in the days preceding the attack. The extent of damage depends on various factors including the extent and location of the clot.
Any chest pain that you can influence by breathing movements or coughing, arm, neck or chest movements or direct pressure on the chest wall is nearly NEVER due to heart attack or angina. If you are in any doubt go to the nearest emergency room or GP clinic because every second saved may save your life.
The greater the muscle death, the weaker the pump function and therefore the poorer the heart’s ability to provide blood supply to all the body organs - hence the condition called heart failure.
Breathlessness arises because the lungs flood with water due to the heart’s failure to adequately pump forwards. 
Who is AT RISK?
Those with:
1. A family history of CAD (men <55 or women < 65 years in the family with CAD) 
    – the most important risk factor (in my opinion)
2. Diabetes
3. Hypercholesterolemia (high cholesterol)
4. Hypertension (high blood pressure)
5. Cigarette smoking as a habit
The seed (gene) for CAD may be inherited and may give rise to problems if nurtured in a favourable environment e.g. obesity, lack of exercise and the other risk factors stated above. Unfortunately, if the hereditary component is strong, even the healthiest living person may fall prey to this condition.
Individuals with high risk potential, should from their 20’s actively pursue healthy lifestyle measures and have basic parameters like BP, blood sugar and lipid profile assessed. Smoking should be strongly discouraged at all ages. It is my personal belief that all individuals should have a baseline assessment of their fasting sugar, cholesterol and blood pressure by the time they reach 30. With prediction modules currently available, it is possible to make overall heart risk assessments to guide preventive strategies.
If you recognize yourself to be an “at risk” individual, then consider getting yourself assessed by a doctor and take the appropriate measures recommended. If you develop any suspicious new symptoms, seek help immediately. Many individuals, doctors included, have tried to deny the symptoms or tried to blame other causes e.g. gastric symptoms when suffering angina or heart attack – even with prior knowledge that they were at high risk. Prompt treatment saves lives!
The doctor’s tools for the evaluation of CAD are not within the scope of this article. 
Basic principles of treatment of CAD
The treatment of stable angina involves:
1. Providing relief of symptoms with drugs that reduce the work load of the heart and thus blood supply demand  
    e.g. beta blockers (which lower the heart speed and the blood pressure), calcium blockers (that expand the
    artery and allow better flow across the narrowing and also lower the blood pressure) and nitrates that work in
    a roughly similar manner. 
2. Protecting the patient from heart attack that may arise from other plaques that might be present – aspirin (anti-
    clot), statin drugs (lower cholesterol and harden plaques). 
There appears to be a generalized reluctance to take these drugs prescribed by doctors due to fears of long-term side-effects. These fears are not based on any scientific fact and whilst some of these drugs may have short term reversible side-effects, most of these drugs have excellent long-term safety profiles. Coronary angioplasty/stenting and coronary bypass surgery is widely practiced and is an effective cure for most patients with symptoms and in certain situations also prolong life. 
Despite the established value of healthy living, the required large risk reductions to “at risk” individuals can only be achieved through drug treatment. Vitamins, antioxidants and the multitude of health supplements widely promoted and consumed have despite extensive investigation, shown no scientific proof of benefit beyond that which we derive from a balanced healthy diet. 
The treatment of heart attack:-
is based on speedy measures to stabilize the patient and to re-open the blocked artery. The options are between using clot busting drugs or using balloon angioplasty. The earlier the blocked vessel is opened, the less the damage and the better the long-term survival of the patient. Unfortunately, the largest delays occur in the patient’s failure to recognize symptoms early and in physically getting to medical facilities for such treatment to be administered early. If treatment can be administered within the first 2 hours, the heart attack may be aborted.
Guide to your personal heart health
1.  Assess your personal risk status – seek medical help if required
2.  Establish a healthy lifestyle. Moderate everything and don’t smoke
3.  If you sense suspicious symptoms or a change in your exercise capacity – see a doctor soon
4.  If deemed to require drugs for diabetes, blood pressure or cholesterol – you are almost definitely going to
     require it as long as you wish to stay healthy and safe.
     You are definitely safer taking these drugs long term than not
5. If you have new symptoms occurring at rest – seek medical attention fast