Coronary Artery Disease


Heart disease is common.  Minor congenital abnormalities affect one hundred live births and more serious abnormalities approximately one in five hundred.  Heart disease has two peculiarities when compared with disease of other organs. First, it is very commonly latent, that is a disease process of for example, the coronary arteries can proceed to an advanced stage before the patient notices any symptoms. Second, the number of symptoms attributable to heart disease is limited and it is common for many different pathologies through a final common symptomatic pathway. 


 

SYMPTOMS OF HEART DISEASE


 




Breathlessness (Dyspnoea)

Breathlessness or dyspnoea is a common symptom of cardiac disease. It is commonly defined as a subjective awareness of increased work in breathing, but the mechanisms responsible for this sensation are incompletely understood and may differ according to the circumstances.

  1. Exertional dysponea. This is breathlessness which comes on during exertion exertion and subsides on resting. It is commonly due either to heart failure or to lung disease. Some patients with angina describe breathlessness rather than chest pain on exertion.
     

  2. Pulmonary Oedema. This is persistent breathlessness resulting from fluid accumulation in the lung as a manifestation of acute left heart failure. The patients looks and feels unwell, and there is peripheral vasoconstriction and tachycardia. Breathing is rapid and shallow, and there is a persistent cough. Sputum is white and frothy, sometimes tinged with pink. Crepitations are heard on auscultation of the chest, initially at the lung bases, later throughout the lungs. Orthopnoea and paroxysmal nocturnal dyspnoea are transient forms of pulmonary oedema.
     

Chest Pain

  1. Angina. This is a choking or constricting chest pain which comes on with exertion, is relieved by rest, and is due to myocardial ischaemia. It is commonly felt retrosternally and may radiate to the left or more rarely the right arm to the throat, jaws  and teeth, or through to the back. The pain may be squeezing, crushing, burning or aching, but seldom stabbing. The pain may be brought on or exacerbated by emotion, and is frequently made worse by large meals or a cold wind. It is relieved by nitrates.
     

  2. Myocardial infarction. The pain is similar in nature and distribution to angina but is more severe, persists at rest, and does not respond to nitrates. There are usually features of sympathetic nervous system activation, and vomiting is common. There may be anxiety and a feeling of impending death.
     

Types and differential diagnoses of chest pain are summarized  below.

Oedema

  1. Peripheral oedema. This is a feature of chronic heart failure and is due to excessive salt and water retention. In ambulant or sedentary patients it usually affects the ankles, legs, thighs and lowers abdomen in that order. In a patient who is lying down it is most apparent over the sacrum. The oedema of heart failure is usually accompanied by  some other symptoms of heart failure, and by a raised jugular venous pressure. Unless it is long-standing and the skin is very tense the oedema pits easily on pressure. 
     

  2. Oedema of chronic venous insufficiency. This together with immobility is very common in the elderly. It usually affects the ankles and lower legs only. The oedema pits readily and redistributes after a night's sleep. However there are no other features of cardiac failure. Oedema is a relatively late and unreliable feature of deep venous thrombosis. However ilio-femoral vein thrombosis can cause severe venous congestion and oedema.
     

Palpitation

Palpitation is an abnormal subjective awareness of the heart beat. Patients can usually distinguish between sporadic and continuous palpitation (for example extrasystoles or a sustained Tachycardia) and between an irregular and a regular pulse. It may be helpful to ask the patient to tap out the  heart rhythm on the table. Palpitation with a regular rhythm and a normal heart rate may be due to sudden vasodilatation (e.g. during perimenopausal flushing).

Syncope

Syncope is loss of conciousness resulting from an inadequate blood supply to the brain. This may be due to sudden vasodilatation, to a sudden fall in cardiac output or to both simultaneously. Postural syncope when due to vasodilator or antihypertensive drugs is an example of the former, and diminished cardiac output from complete heart block or a very rapid tachycardia of the latter.

  • Vasovagal fainting. This involves both a reflex cardiac slowing mediated by the vagus and sudden withdrawal of peripheral sympathetic tone. It is a complex centrally mediated reflex which tends to be initiated when pain or a powerful emotional stimulus is inflicted against a background of intense sympathetic stimulation. A very similar reflex can also be triggered by mechano-receptors from the endocardium of the left ventricle. This accounts for the fainting reflex which occurs in patients with pulmonary embolism or aortic stenosis .

Other Symptoms

  1. Tiredness is a common complaint with severe heart failure and with ischaemic heart disease. Sometimes it is the consequence of treatment rather than the disease itself, e.g. beta-blockade or hypokalaemia from diuretics. In those with valvular disease without heart failure it lead to a suspicion of infective endocarditis.

 

Coronary artery disease


The coronary arteries are branching blood vessels on the surface of the heart that supply the heart muscle with the nutrient-rich blood it needs to function. If these arteries become narrowed or blocked by the buildup of fatty deposits (plaque) in a process called Atherosclerosis , the heart muscle does not get a sufficient amount of oxygen and may be damaged. This condition called coronary artery disease, can lead to a heart attack.

How does heart gets its own blood?


The heart is primarily a mechanical muscle pump which contracts and pushes blood into the circulation to supply oxygen and nourishment to all our body systems. It pumps blood into the arterial blood channels of our body. The blood vessels are channels or tubes that carry blood to and from all our organs such as the brain, kidneys, lungs, heart muscle, skeletal muscles, stomach, intestines, skin , etc.

Its own quota of blood is obtained through an exclusive set of arterial channels which originate from the mouth of the arota. These special tubes travel the surface of heart as if embracing it. These are shaped like a "corona" (crown), hence the name coronary arteries. The pencil-sized coronary arteries originate from the principle arterial trunk known as aorta. The main trunk aorta, of course, arises from the left ventricle. There are three main coronary arteries and like the branch of a tree, each main coronary artery divides and subdivides to transport oxygenated blood to all cells of the heart muscle. The smallest branches often interlink with one another and form what are known as collaterals.

Names of three principal coronary arteries are:

  • Left anterior descending artery

  • Left circumflex artery

On an average our heart beats 72 times per minutes.

Blood Pressure Regulation

As blood flows from your heart to your blood vessels, it pushes against the walls of your blood vessels. This pressure is measured in millimeters of mercury (mmHg). The reading often is recorded as two numbers—the pressure while the heart beats (systolic pressure) over the pressure while the heart relaxes between beats (diastolic pressure). The numbers are written one above or before the other. The systolic number comes first, or on top, and the diastolic number comes second, or on the bottom.

 

What is Atherosclerosis?

Atherosclerosis is the buildup of fatty material called plaque on the inside walls of arteries. The formation of plaque begins when a fatty substance called lipoprotein-made of cholesterol and other fatty materials and protein-deposits itself on the inside walls of arteries. This process stimulates abnormal growth of cells in the lining of the arteries, which causes scarring and inflammation. The scarring and inflammation damage the artery walls, leading to the formation of plaque. Over a lifetime, as more and more fatty deposits accumulate, the size of the plaque grows, potentially narrowing the artery or even blocking it completely. Blocking of an artery can cut off the flow of blood to vital organs, destroying those tissues. If the blockage occurs in the arteries that nourish the heart, the result is chest pain (angina ) or a heart attack . If the blockage cuts off the flow of blood to the brain, the result is a stroke . Blockages in blood vessels in the legs can make walking painful.
 







 

FACTORS CONTRIBUTING TO A CORONARY ARTERY disease 

There are several factors that can increase your risk of having a heart attack, some of which you can  control. You cannot control factors such as age or a family history of heart disease. The four biggest risk factors for heart disease in women-high cholesterol level, smoking, high blood pressure, and diabetes-are controllable. You can do many relatively simple things to reduce your risk of heart disease, including eating a low-fat diet, exercising regularly, not smoking, maintaining a healthy weight, and getting treatment for high blood pressure or diabetes if necessary.

  • High cholesterol level High levels of cholesterol in the blood increase the likelihood that the coronary arteries will become narrowed, which can lead to a heart attack. Before menopause, the presence of the female hormone estrogen in the blood gives most women lower total cholesterol levels than men and higher levels of the good, heart-protecting cholesterol called high-density lipoprotein (H D L). However, estrogen's heart-protecting advantage is lost after menopause, when the ovaries reduce their production of hormone. The presence of estrogen in women's blood is one reason they tend to develop heart disease later in life than men.

    You can help maintain your cholesterol level in a healthy range by eating a low-fat diet  and getting regular exercise . If you have a high cholesterol level and you already have heart disease, or you have other risk factors for heart disease (such as high blood pressure), your doctor may recommend a medication to lower your cholesterol level.
     

  • Smoking- Smoking decreases the levels of two substances in the blood that help protect against heart disease-HDL Cholesterol and the female hormone estrogen. Smoking as few as one to four cigarettes a day doubles your risk of heart disease; smoking more than a pack a day increases your risk up to 15 times. 

    Tobacco smoke contains small quantities of carbon monoxide, which combines irreversibly with haemoglobin in the red blood cells.
    Normally haemoglobin carries out this function:

    oxygen + haemoglobin (reversible reaction) oxy-haemoglobin
    However when carbon monoxide is inhaled, the following occurs:

    carbon monoxide + haemoglobin (Irreversible Reaction) carboxy-haemoglobin
    Smoking also puts strain on your heart because it causes blood vessels to constrict, which reduces the flow of blood to your heart and makes the heart work harder to pump blood to other parts of the body. In addition, toxic substances in cigarette smoke may directly damage artery walls and cause Atherosclerosis, a process in which fatty deposits accumulate on the inside of artery walls, potentially narrowing or blocking the blood vessels. When you stop smoking, your risk of heart disease drops rapidly.
     

Characteristic of Coronary artery disease in women

  • Presentation
    Women present at a later age.
    In women, typical angina is less predictive of coronary artery disease (pretest probability is 50 to 60 percent in women versus 80 to 99 percent in men).
    Women may present with shoulder or jaw pain, dyspnea or nausea.
     

  • Risk factors
    Diabetes has a stronger influence in women.
    High HDL cholesterol levels, which lower the risk of coronary artery disease, are more common in women.
    The roles of total cholesterol, LDL cholesterol and lipoprotein(a) in women are unclear.
    The risk of coronary artery disease increases after menopause.
     

 

Diagnosing Coronary artery Disease 


If you experience angina or are at high risk of heart disease, your primary care doctor may refer you to a cardiologist, a doctor who specializes in disorders of the heart. To determine the health of your heart, you may have one or more of the following tests. These tests are listed in the order in which you are likely to have them, starting with the test that is easiest to perform and the least invasive (does not require entering your body or cutting into it).

  • Electrocardiogram An electrocardiogram (ECG but sometimes called an EKG) is a painless test that records the flow of electricity through your heart. Electrodes attached to your skin transmit this electrical activity to a machine that prints it out on a recording that your doctor can read. Each beat your heart starts with an electrical impulse. When there is an abnormality in your heart, the flow of electricity through your heart changes. An ECG can help detect such a change. Your doctor can also use an ECG to help diagnose a wide range of heat problems-including abnormal heart rhythms, abnormal thickening of the heart muscles, defects in electrical impulses through the heart and  damage to heart tissues resulting from heart disease.   However this test sometimes fails to detect the presence of heart disease, especially if it has not caused any damage to the heart muscle.   
     
    If the ECG reveals irregular heart rhythms, your doctor may want to monitor your heart rate over a 24-hour period using a portable ECG machine called a Holter monitor. The Holter monitor is a device that is about the size of a portable cassette tape player. The monitor is attached to a shoulder strap. Electrodes attached to the skin of your chest transmit your heartbeat to a cassette tape inside the monitor, which is later interpreted by your doctor. You wear the monitor continuously for 1 day while you follow your usual routine. Your doctor may also recommend using the Holter monitor for 24 hours if you have been experiencing chest pain, dizziness, fainting episodes, or heart palpitations (sudden, rapid heartbeats).

    The monitor can detect periods of ischemia, which occur when the oxygen supply to the heart is temporarily decreased. These episodes of ischemia may cause no symptoms and are then called "silent" episodes because you are unaware of them. However, with or without symptoms, these periods of ischemia may put you at increased risk of having a heart attack. Ischemia usually indicates that your heart needs more oxygen than your arteries are able to supply, usually because of a blockage caused by Atherosclerosis. If you are experiencing episodes of ischemia, your doctor may prescribe medication to reduce their occurrence or recommend further testing to evaluate the severity of your condition and help determine treatment.
     

  • Exercise stress test An exercise stress test is an ECG that is taken while you walk on a treadmill or ride a stationary bicycle. The purpose of this test is to determine whether your heart is getting enough oxygen during exertion, when it requires more oxygen than usual. Electronic sensors are attached to your body and connected to an ECG machine. You begin exercising, slowly at first and then more quickly, until you reach a target heart rate.   

    Your target heart rate is expressed in a number of beats per minute that is determined by your age and physical condition. Your doctor will monitor your blood pressure at the same time. An exercise stress test does not usually detect a problem unless one or more coronary arteries are more than 50-percent blocked. The signs of significant narrowing in a coronary artery include intolerable fatigue or chest pain while exercising or an irregular hear rhythm detected on the ECG. In this case, further testing, such as Angiography , is necessary to determine the location and extent of the blockage.
     

 

UNDERSTANDING HEART ATTACK


When a blood clot blocks a coronary artery, the heart muscle is deprived of oxygen. The result is a heart attack.
Part of the heart muscle may die or become damaged; sometimes the heart fails altogether, causing death. A heart attack can be sudden, painful, and easy to identify, or it can cause few or no symptoms and go entirely undetected. A heart attack can feel different to different people. You may have crushing pain, or a squeezing sensation in your chest that may spread to your neck, jaw, arms, or down your back; or back. Women are less likely than men to call for help when they are having a heart attack, possibly because they have not been diagnosed with heart disease or they think that heart attacks only happen to men. heart attacks in women are often mistaken for indigestion.

A heart attack-or, in medical terms, myocardial infarction-occurs when the blood supply to an area of the heart is severely reduced or cut off. The process begins when one of the coronary arteries (the blood vessels that supply blood to the heart) becomes narrowed by deposits of a fatty substance called plaque. The buildup of plaque inside arteries is a process called atherosclerosis . A narrowed coronary artery is then blocked further, sometimes completely, by an obstruction, usually a blood clot that sticks to the plaque. The formation of a blood clot in an area of an a artery in which plaque has built up is called a coronary thrombosis. If the supply of oxygen-rich blood to the heart is severely blocked and remains blocked for too long, the lack of oxygen causes irreversible damage to the heart muscle. Extensive damage to the heart muscle is often fatal because the heart can no longer continue to pump blood to the rest of the body.

If you are having a heart attack, the faster you get help, the greater are your chances of surviving it. eighty percent of people who do survive a heart attack can return to their normal life, including work, within 3 months. The following facts show how acting quickly can help save your life if you think you are having a heart attack.

  • The longer you delay treatment for a heart attack, the more severely your heart is likely to be damaged.
     

  • Most people who die of a heart attack do so within 2 hours of the onset of symptoms.

WARNING SIGNS OF A HEART ATTACK

Call your immediately if you are experiencing any of the following symptoms:

  • Uncomfortable tightness or pressure, fullness, or squeezing deep in your chest or across your chest 
     

  • Chest pain that spreads to your neck, jaws, or down your back
     

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TREATING CORONARY ARTERY DISEASE



Minimizing all risk factors to slow down atherosclerosis and prevent myocardial infarction (MI) is considered important. Efficient secondary intervention usually includes ASA, beta-blocker, statin and discontinuation of smoking

Besides, a woman who has a heart attack is more likely than a man to die of it. This is partly because women tend to be older than men when they have their first heart attack. Women are also less likely to receive aggressive treatments, such as medication to dissolve blood clots during a heart attack or surgery to open blocked arteries (angioplasty ) or to redirect blood flow from narrowed arteries (coronary bypass surgery ). Knowing the many effective treatments that are available for heart disease can help you get the treatment you may need.


Medication

The array of drugs for treating heart disease continues to grow. It often some adjusting to determine the right combination of medications for a particular person. Your doctor may prescribe different drugs alone or in combination to find what works best for you and causes the fewest side effects. It is important to tell your doctor about any side effects you are experiencing while you are taking any medication. 

Heart disease medication fall into the following major categories.

  • Alpha blockers -Alpha blockers are drugs that help lower blood pressure by preventing the blood vessels from constricting. These drugs also prevent hormones your body releases in response to stress (such as adrenaline) from raising your blood pressure. Alpha blockers are often combined with other drugs to lower blood pressure. Alpha blockers sometimes cause dizziness.
     

  • ACE inhibitors- ACE inhibitors (ACE stands for angiotensin-converting enzyme) help lower blood pressure by blocking production of a hormone produced by the kidneys called angiotensin II, which causes blood vessels to constrict. These drugs are often used to control blood pressure in people with diabetes  or congestive heart failure . ACE inhibitors can cause a dry cough in some people.
     


Surgical options

  • Angioplasty and other procedures to open arteries A variety of procedures can be used to open a narrowed or blocked artery. In some of these procedures, a tiny balloon (for angioplasty) or cutting device (for atherectomy) attached to the end of a long, thin tube (catheter) is inserted into the blocked artery to open it. In many cases, these procedures to open an artery can replace coronary bypass surgery , which carries higher risks and has a longer recovery time. You may be a good candidate for this type of procedure if you have a significant blockage in only one or two of your arteries or if you have angina (chest pain) that cannot be controlled with medication.


Before any of these procedures to reopen blocked arteries you will be given a sedative to relax you and a local anesthetic at the site at which the catheter enters your body-usually the skin over the femoral artery in your groin or upper thigh. The cardiologist threads a thin, flexible wire called a guide wire through this artery into your coronary artery to a point just beyond the blockage. A catheter is then placed in the coronary artery, and the size and location of the blockage is confirmed by injecting dye through the catheter into the blocked artery to show its outline on an X -ray.
 

  • In balloon angioplasty, a catheter with a balloon at its tip is threaded into the artery, over the guide wire, to the site of the blockage. A tiny balloon at he end of the catheter is inflated at the blockage site, sometimes several times for 30 to 120 seconds each time. The pressure of the balloon pushes the fatty buildup (plaque) back against the artery walls and opens the artery to allow blood to flow more freely. Balloon angioplasty is virtually painless, but you may feel some pressure in your chest when the balloon is inflated. When the procedure is finished, the doctor removes the catheter and balloon and performs another angiogram to see if the artery has been opened successfully.



 


 
 

 

 Cardiac rehabilitation

 

Cardiac rehabilitation is a program of

  • Regular exercise
     

  • Low-fat diet
     

  • Keep your cholesterol level low to prevent plaque from building up in your arteries again.

    A cardiac rehabilitation program can benefit anyone who has heart disease, whether or not he or she has had a heart attack or any kind of heart surgery or procedure. Ask your cardiologist for a recommendation regarding diet and lifestyle modifications .

Although you can maintain an exercise program and healthful diet on your own, it is far better to join an organized program because you receive support from an experienced staff. Also, you are with other people who are going through the same experience. The usual rehabilitation process starts in the hospital a day or two after surgery with simple activities such as moving to a bedside chair while an attendant makes the bed. You are encouraged to gradually engage in more activity.

Quit smoking- Smoking should be discontinued and alcohol consumption should be limited to moderate amounts.
 

Hypertension- should be treated optimally. The target level of below 140/90 mmHg should be reached.

Effective reduction of hyperlipidaemia is often possible only by using statins. Target levels:

  • total cholesterol level below 5.0 mmol/L

  • Low-density lipoprotein (LDL) value below 3.0 (-2.5) mmol/L. Drug therapy is indicated if low-density lipoprotein does not decrease to below 3.0 with drugless therapy.

Treating obesity

  • Weight must be reduced to a target of body mass index (BMI) 28.

  • Recognize metabolic syndrome and consider starting combination therapy with a statin and fibrate

Physical exercise

  • Regular exercise improves the sense of well being and prognosis by reducing many risk factors

On the basis of epidemiological studies, hormone replacement therapy (HRT) has been considered beneficial for women with risk factors. A randomized secondary prevention study (Heart and Estrogen/Progestin Replacement Study)  did not, however, show any benefit from hormone replacement therapy .
 

 A heart-healthy lifestyle

A healthy lifestyle can greatly reduce your risk of heart disease. Here are the most important things you can do to keep your heart strong and working efficiently: 

  • Eat a low-fat, low-cholesterol diet. Saturated fats and cholesterol in foods can raise your cholesterol level-a strong risk factor for heart disease.
     

  • Get regular exercise. You are twice as likely to develop heart disease if you are inactive than if you exercise regularly. Exercise that increases your heart rate-such as brisk walking, swimming, or weight lifting-lowers your blood pressure and cholesterol level, and strengthens your heart so that it can pump more blood with less effort.
     

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  • Fish is part of a heart-healthy diet. It contains omega-3 fatty acids, which help improve blood cholesterol levels and prevent blood clots.
     

  • Eating plenty of fruits and vegetables is also encouraged. Fruits and vegetables contain antioxidants — vitamins and minerals that help prevent everyday wear and tear on your coronary arteries.
     

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Prevention of CAD:

How you live your life can greatly affect the health of your heart and your coronary arteries. Taking the following steps can help you prevent coronary artery disease, as well as a heart attack and congestive heart failure:

  • Get regular medical checkups. Some of the main risk factors for coronary artery disease — high blood cholesterol, high blood pressure and diabetes — have no symptoms in the early stages. Coronary artery disease itself may produce no symptoms. But your doctor can perform tests to check that you're free of these conditions. If a problem is found, you and your doctor can manage it early to prevent complications.

  • Control your blood pressure. All adults should have their blood pressure checked every 2 years. Your doctor may recommend more frequent measurement if you have high blood pressure or a history of heart disease.

 

Dated 23 March 2012

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