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Vascular Disease Vol 1 and Vol 2

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Product Description

Vascular Disease Vol 1 and Vol 2
Chapter 1: Circulatory system structure and function
Chapter 2: Atherosclerosis
Chapter 3: Cerebrovascular disease
Chapter 4: Aneurysms
Chapter 5: Upper limb vascular disease
Chapter 6: Chronic lower limb ischaemia
Chapter 7: Acute lower limb ischaemia
Chapter 8: Vascular access for haemodialysis
Chapter 9: Entrapment syndromes in vascular patients
Chapter 10: Management of the diabetic foot
Chapter 11: Deep vein thrombosis
Chapter 12: Varicose veins
Chapter 13: Chronic venous insufficiency and venous leg ulcers
Chapter 14: HIV vascular disease
Chapter 15: Lymphoedama

Additional Information

Type

Ebook, Printed

INTRODUCTION The purpose of this project is to help disseminate information about the prevention and management of vascular diseases. Such educational activities are core functions of the Vascular Society of South Africa (VASSA) and are performed by our members as a service to the South African public and communities in need. On behalf of the society I thank all the individuals involved with these projects and congratulate the editor and authors of this book. pic

Jay Pillai President Vascular Society of Southern Africa Senior lecturer, University of the Witwatersrand

 

This is not a vascular textbook of reference work. Our brief from the publishers and series editor of the EasiRead series was to produce a pocket book containing information about the most important vascular conditions, that it must be understandable to the informed patient and primary healthcare worker, but that it also contains information of interest to the general practitioner / family physician. We hope that we have succeeded in this endeavour.

Due to space constraints; some important vascular conditions, such as mesenteric, renovascular hypertension, carotid body tumours; etc,, have not been covered, but hopefully the opportunity to cover these topics may arise at a later date.

I would like to thank my colleagues for their academic contribution to this pocket book as well as the Vascular Society of Southern Africa for their support. Finally I would like to express my sincere gratitude to the sponsor who made this publication possible.

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Cobus van Marle Editor Alphabetical order of Authors

Abdool-Carim T MBChB (Natal)FRCS (Edin)Specialist Vascular Surgeon,Milpark Hospital,Johannesburg Professor -Department of Surgery, University of Witwatersrand Forlee M MBChB FCS(SA) CVS(SA) Specialist Vascular Surgoen, Kingsbury Hospital, Cape Town Senior Horonary Lecturer - Department of Surgery, University of Cape Le Roux D A MBChB (UP) FCS (SA) CVS (SA) Specialist Vascular Surgoen, Sunninghill Hospital, Johannesburg Consultant - Department of Surgery, University of Witwatersrand Matley P MBChB M MED (Surg) FCS (SA) Specialist Vascular Surgoen, Kingbury Hospital, Cape Town Mistry P P MBChB (UP) M.Med.(Surg)FCS(SA) Specialist Vascular Surgoen, Sunninghill & Fourways Hospital Consultant - Department of Surgery, University of Witwatersrand Tudhope L MBChB (UP) M.Med.(Surg) (SUP)BA(Unisa) Specialist Vascular Surgoen, Montana Hospital, Pretoria Tunnicliffe J MBChB FCS (SA) Specialist Vascular Surgoen, Constantiaberg and Kingsburg Hospital, Capetown Van Marle J MBChB (UP) M Med(Surg)(UP) Cum Laude FCS(SA) Extra-ordinary Professor - Department of Surgen, University of Pretoria and Kingsburg Veller M MBChB M Med(Surg)(UP)FCS(SA) Specialist Vascular Surgoen, Donald Gordon Medical Centre, Johanneburg Professor and Head - Department of Surgen, University of Pretoria and Witwatersrand Weir GR MBChB (UP) M Med(Surg)(UP) FCS(SA) Specialist Vascular Surgoen, Eugene Marais, Hospital, Pretoria Wesseis P MBChB M Med(Hem) Cert.Clinical Hem. (CMSA) Hematologist, Little Company of Mary, Hospital, Pretoria

CHAPTER 2

 

Atherosclerosis

Atherosclerosis is a condition which affects the arteries i.e. blood vessels that carry oxygen rich blood to the heart and other parts of the body. Plaque forms as a result of inflammation in the arterial wall and consists of lipid accumulation (cholesterol), fibrous tissue, calcium and other substances found in the blood.

In time, plaques become larger and thicker and makes arteries harder and narrower which reduces the blood flow through the artery. (Fig 2.1) 2015-12-02 11-58-02 AMSometimes, a plaque may develop a tiny crack on the inside surface of the blood vessel (rupture of plaque), This may trigger a blood clot (thrombus) to form over the patch of atheroma, which may completely block the blood flow. Depending on the artery affected, a blood clot that forms on a patch of atheroma can cause a heart attack, a stroke, or decreased blood flow to the arteries in the legs.

Risk Factors Most people develop some atherosclerosis as they get older. However, certain factors increase the risk of developing extensive atheroma and at a younger age, These risk factors include:

Lifestyle risk factors that can be prevented or changed:
  • Smoking
  • Lack of physical activity (a sedentary lifestyle)
  • Obesity
  • An unhealthy diet and eating too much salt
  • Excess alcohol
Treatable or partly treatable risk factors:
  • Hypertension (high blood pressure)
  • High cholesterol blood level
  • High triglyceride (fat) blood level
  • Diabetes
  • Kidney diseases causing diminished kidney function
Fixed risk factors - ones that you cannot alter:
  • A strong family history. This means if you have a father or brother who developed heart disease or a stroke before they were 55, or in a mother or sister before they were 65
  • Being male
  • Severe baldness in men
  • An early menopause in women
  • Age. The older you become, the more likely you are to develop atheroma
  • Ethnic group. For example, Afrikaner families with the familial hypercholesterolemia problem have a history of early onset complications

If you have a fixed risk factor, you may want to make extra effort to tackle any lifestyle risk factors that can be changed. Note:some risk factors are more dangerous than others. For example, smoking and diabetes probably causes a greater risk to health than obesity. Also, risk factors interact. So, if you have two or more risk factors, your health risk is much more increased than if you just have one. For example, an Oxford study found that men aged 50 who smoke, have high cholesterol and high blood pressure die, on average, 10 years earlier than men who do not have these risk factors. Research is looking at some other factors that may increase the risk for vascular disease: for example, high blood levels of fibrinogen, C­ reactive protein, apolipoprotein B. and homocysteine are being investigated as possible risk factors.

Lifestyle risk factors that can be prevented and/or changed:Smoking Lifetime smoking roughly doubles your risk of developing heart disease. The chemicals in tobacco get into the bloodstream from the lungs and damage the arteries and other parts of the body. Your risk of having a stroke, and developing other diseases such as lung cancer are also increased. Stopping smoking is often the single most effective thing that a person can do to reduce their health risk. The increased risk falls rapidly after stopping smoking (although it takes a few years before the excess risk reduces completely).

Lack of physical activity - A sedentary lifestyle People who are physically active have a lower risk of developing cardiovascular diseases compared to inactive people.Aerobic exercise lowers blood pressure and elevates the level of good cholesterol (HDL). To gain health benefits you should do at least 30 minutes of moderate physical activity, on most days (at least five days per week).

  • 30 minutes in a day is probably the minimum to gain health benefits. However, you do not have to do this all at once. For example, cycling to work and back 15 minutes each  way adds up to the total of 30 minutes.
  • Moderate physical activity means that you get warm, mildly out of breath, and mildly sweaty. The  intensity should induce sweating after about 15 minutes, but should still be comfortable enough to allow  for a conversation with a companion.
 

Examples include brisk walking, jogging, swimming, cycling, etc. If using a heart rate monitor, the American Heart Association recommends not training above a rate of (220 minus your age)x 2/3 in order to not strain your heart. For example: in a 40 year old male: 220-40=180 x 2/3 = 120.

  • On most days. You cannot store up the benefits of physical activity. You need to do it regulary.
 

Obesity and overweight On average, if you are obese and reduce your weight by 10%, your chance of dying at any given age is reduced by about 20%. This is mainly because you are less likely to develop cardiovascular diseases, diabetes, or certain cancers. The increased health risk of obesity is most marked when the excess fat is mainly in the abdomen rather than on the hips and thighs. As a rule, a waist measurement of 102 cm or above for men (92 cm for Asian men) and 88 cm or above for women (78 cm for Asian women) is a significant health risk. The body mass index (BMI) can also be used and is calculated using the formula (weight in kg) divided by (height in metres) By definition BMI > 25 = overweight, BMI > 30 = obese and BMI > 35 = morbidly obese (i.e. likely to cause health problems).

Diet Eating healthily helps to control obesity, and lower your cholesterol level. Both of these help to reduce your health risk. Also, there is some evidence that eating oily fish (herring, sardines, mackerel, salmon, kippers, pilchards, fresh tuna, etc) helps to protect against heart disease. It is probably the omega-3 fatty acids in the fish oil that helps to reduce the build-up of atheroma. Fruit and vegetables, as well as being low in fat, also contain anti-oxidants and vitamins which may help to prevent atheroma building up. Briefly, a healthy diet means:

    • AT LEAST five portions, ideally more, of a variety of fruit and vegetables per day.
    • THE BULK OF MOST MEALS should be starch-based foods (such as cereals, wholegrain bread,  potatoes, rice, pasta), plus fruit and vegetables.
    • NOT MUCH fatty food such as fatty meats, cheeses, full-cream milk, fried food, butter, etc. Use low-fat, mono-or poly-unsaturated spreads. One study conducted at Harvard University found that replacing saturated fats with poly-unsaturated fats is an effective way of lowering your risk of heart attacks and other serious problems from heart disease.
• INCLUDE 2-3 portions of fish per week, at least  one of which should be oily (such as herring, mackerel, sardines, kippers, salmon,or fresh tuna).
  • LIMIT SALT to no more than 6g a day (and less for children).
  • If you eat meat is best to eat lean meat, or poultry such as chicken.
  • If you do fry, choose a vegetable oil such as sunflower, rapeseed or olive.
 

Salt Adults should eat no more than 6g salt a day.This is about a teaspoon of salt. A research study followed up people for several years and looked at their salt intake. Those who cut back from about 10g per day to about 7g per day or less, on average, reduced their risk of developing a cardiovascular disease by about a quarter. So, even a modest reduction in intake can make quite a big difference. About three quarters of the salt we eat is already in the foods we buy. By simply checking food labels and choosing foods with lower salt options, it can make a big difference. A tip: sodium is usually listed on the food label. Multiplying the sodium content by 2.5 will give the salt content. Also, try not to add salt to food at the table.

Alcohol Drinking a small or moderate amount of alcohol probably reduces the risk of developing cardiovascular diseases (by 38% compared with non-drinkers in one study). Moderate means 1-2 units per day - which is up to 14 units per week. Drinking more than 15 units per week does not reduce the risk, and drinking more than the recommended upper limits can be harmful. Men should drink no more than 21 units per week (and no more than four units in any one day). Women should drink no more than 14 units per week (and no more than three units in any one day). One unit is in about half a pint of normal strength beer, or two thirds of a small glass of wine, or one small pub measure of spirits.

Other treatable or partially treatable risk factors High blood pressure You should have your blood pressure checked regularly. High blood pressure usually causes no symptoms, so you will not know if it is high unless you have it checked. High blood pressure is a risk factor for developing a cardiovascular disease (such as a heart attack or stroke), and kidney damage. If you have high blood pressure, over the years it may damage your arteries and put a strain on your heart. In general, the higher your blood pressure, the greater the health risk. High blood pressure is just one of several possible risk factors for developing a cardiovascular disease. High blood pressure can be lowered by: losing some weight if you are overweight, regular physical activity, reducing salt intake and stopping smoking. Medication may be advised if your blood pressure remains high.

Treatment with medication: Medication to lower blood pressure is usually advised for:

  • All people who have a blood pressure that remains at 160/100 mmHg or above after a trial of any  relevant lifestyle changes.
  • People with a blood pressure that remains at 140/90 mmHg or above after a trial of any relevant lifestyle  changes AND who have:
  • Diabetes; or
  • An existing cardiovascular disease; or
  • A 2 in 10 risk or more of developing a cardiovascular disease within the next 10 years
  • People with a blood pressure of 130/80 mmHg or more who have certain diseases. For example, people who have certain complications from diabetes, people who have had a recent heart attack, stroke or transient ischaemic attack (TIA) - sometimes called a mini-stroke. Also, some people with certain chronic  (ongoing) kidney diseases.
What Is the target blood pressure to aim for?
  • For most people who are otherwise well, the target is to reduce blood pressure to 140/90 mmHg or    below.
  • In some people, the target is to get the blood pressure to an even lower level. This generally applies to people who have diseases where very good blood pressure control is important. This includes:
  • People who have a cardiovascular disease
  • People with diabetes
  • People who have a chronic kidney disease

What medicines are used to lower blood pressure? There are several medicines that can lower blood pressure. The one chosen depends on such things as: if you have other medical problems; if you take other medication; possible side-effects of the medicine; your age; your ethnic origin, etc. Some medicines work well in some people, and not so well in others. One or two drugs may be tried before one is found to suit.

One drug reduces high blood pressure to the target level in less than half of cases. It is common to need two or more different drugs to reduce high blood pressure to a target level In about a third of cases, three drugs or more are needed to get blood pressure to the target level. In some cases, despite treatment, the target level is not reached. However, although to reach a target level is ideal, you will benefit from any reduction in blood pressure. Remember that high blood pressure is a life-long problem which will require life-long management.

Cholesterol and other lipids Cholesterol is a lipid (fat chemical) that is made in the liver from fatty foods that we eat. A certain amount of cholesterol is present in the bloodstream. You need some cholesterol to keep healthy. Cholesterol is carried in the blood as part of particles called lipoproteins. There are different types of lipoproteins, but the most relevant to cholesterol are:

  • Low-density lipoproteins canying cholesterol (LDL cholesterol). This is often referred to as bad  cholesterol. This is the one mainly involved in forming atheroma. The majority of cholesterol in the blood  is LDL cholesterol, but how much varies from person to person.
  • High-density lipoproteins carrying cholesterol (HDL cholesterol). This is often referred to as good cholesterol. This may prevent atheroma forming.

What factors affect the blood level of cholesterol? In most people, the cholesterol level reflects the amount of fat that you eat. Other factors also have an effect, as different people who eat the same amount of fat can make different amounts of cholesterol. In general, however, if you eat less fat your cholesterol level is likely to go down. In some people a high cholesterol level is due to another condition. For example, an under active thyroid gland, obesity, drinking a lot of alcohol and some rare kidney and liver disorders can raise the cholesterol level.

In some people a very high level of cholesterol runs in the family, due to a genetic problem with the way cholesterol is made. One example is called familial hypercholesterolemia.

In general, the higher the blood cholesterol level, the greater the risk of developing cardiovascular diseases.The risk that a high cholesterol level poses is greater if you also have other risk factors such as diabetes or high blood pressure. As a rule, no matter what your cholesterol level is, lowering the level reduces your risk. This is why people at high risk of developing a cardiovascular disease are offered medication to lower their cholesterol level.

Cholesterol blood levels The following levels are generally regarded as desirable:

  • Total cholesterol (TC) - 5.0 mmoI/L or less.
  • Low-density lipoprotein (LDL) cholesterol after an overnight fast: 3.0 mmoI/L or less.
  • High-density lipoprotein (HDL) cholesterol: 1.2 mmoI/L or more.
  • TC/HDL ratio: 4.5 or less. That is, your total cholesterol divided by your HDL cholesterol.This reflects the fact that for any given TC level, the more HDL, the better.
As a rule, the higher the LDL cholesterol level, the greater the risk to health. A high blood level of triglyceride, another type of lipid (fat), also increases the health risk.

Can diet lower my cholesterol level? Changing from an unhealthy diet to a healthy diet can reduce a cholesterol level. Dietary changes alone, however, rarely lower a cholesterol level enough to change a person's risk of cardiovascular disease from a high-risk category to a lower-risk category.Any extra reduction in cholesterol due to diet is helpful though. A healthy diet has other benefits too apart from reducing the level of cholesterol.

What treatments are available to reduce the risk? If you are at high risk of developing a cardiovascular disease then treatment with medication is usually advised along with advice to tackle any lifestyle issues. These include: Stalins. are a group of medicines that are commonly used to reduce the level of cholesterol in the blood. They include atorvastalin, fluvastatin, pravastatin, rosuvastatin, and simvastatin. They each have different brand names. Statins work by blocking the action of a certain enzyme (chemical) which is needed to make cholesterol the liver.

    • Bile acid sequestrants
which include cholestyramine, colesevelam and colestipol. They work by binding to bile acids which are passed into the gut from the liver and gallbladder. This stops bile acids being reabsorbed into the bloodstream which has a knock-on effect of lowering cholesterol.
    • Fibrates
which include bezafibrate, ciprofibrate, fenofibrate, and gemfibrozil. One of these is used mainly if you have a high level of triglyceride (another type of lipid) with or without a high cholesterol level.  
    • Nicotinic acid
may be tried if other medicines do not work. It is not used often, as it has a high rate of side-effects such as facial flushing, feeling sick, vomiting and headache.  
    • Ezetimibe
is sometimes used in certain situations in combination with a statin, or on its own. It prevents the absorption of cholesterol from the gut.  
    • Fish oils
may help to reduce blood lipid levels. These occur naturally in oily fish such as mackerel. This is why at least 1-2 portions of oily fish per week are recommended in a healthy diet. Dietary supplements ('fish oil tablets') are also available. However, the value of fish oil supplements is controversial, as the evidence from research trials is unclear. Diabetes and kidney disease The increased risk that these conditions pose to developing cardiovascular diseases can be modified. For example, good control of blood sugar levels in people with diabetes reduces the risk. Good control of blood pressure in people with diabetes and kidney diseases reduces the risk.

Assessing (calculating) your cardiovascular health risk A 'risk factor calculator' is commonly used by doctors.This can assess your cardiovascular health risk. A score is calculated which takes into account all your risk factors such as age, sex, smoking status, blood pressure, cholesterol level, etc.The calculator has been devised after extensive research that monitored thousands of people over a number of years. The score gives a fairly accurate indication of your risk for developing cardiovascular disease over the next 10 years.

Who should have their cardiovascular health risk assessed? Current guidelines advise that the following people should be assessed to find their cardiovascular health risk:

  • All adults aged 40 or more.
  • Adults of any age who have:
  • A strong family history of early cardiovascular disease.This means if you have a father or brother who developed heart disease or a stroke before they were aged 55, or in a mother or sister before they were  aged 65.
  • A first-degree relative (parent, brother, sister, child) with a serious hereditary lipid disorder. For  example, familial hypercholesterolaemia or familial combined hyperlipidaemia. These diseases are uncommon.
 

If you already have cardiovascular disease or diabetes you are already considered to be in the high-risk group.

What does the assessment involve?

A doctor or nurse will:
  • Do a blood test to check your cholesterol and glucose (sugar) level.
  • Measure your blood pressure and your weight.
  • Ask you if you smoke.
  • Ask if there is a history of cardiovascular diseases in your family (your blood relations). If so, at what age the diseases started in the affected family members.
 

A score is calculated based on these factors plus your age and your sex.An adjustment to the score is made for certain other factors such as strong family history and ethnic origin. The calculators are evolving all the time. The one which has been used for a long time is called Framingham. However, many health professionals are moving over to QRISK®2 which is more accurate and takes into account many other factors, such as whether you have a condition called atrial fibrillation,or kidney disease. The QRISK®2 calculator can be found online at www.qrisk.org

What does the assessment score mean? You are given a score as a % chance. So, for example, if your score is 30% this means that you have a 30% chance of developing a cardiovascular disease within the next 10 years. This is the same as saying a 30 in 100 chance (or a 3 in 10 chance). In other words, in this example, 3 in 10 people with the same score that you have will develop a cardiovascular disease within the next 10 years. Note: the score cannot say if you will be one of the three. It cannot predict what will happen to each individual person. It just gives you the odds.

You are said to have a:
  • High risk- if your score is 20% or more. That is, a 2 in 10 chance or more of developing a cardiovascular disease within the next 10 years.
  • Moderate risk- if your score is 10-20%. That is, between a 1 in 10 and 2 in 10 chance.
  • Low risk - if your score is less than 10%. That is, less than a 1 in 10 chance.