THE ROLE OF THE GENERAL PRACTITIONER IN THE PREVENTION AND

MANAGEMENT OF CARDIOVASCULAR DISEASE

 Dr Paul Hill

Specialist Family Physician

Cardiovascular disease is the leading cause of death worldwide, killing 17 million people annually. General practitioners, as the gatekeepers to healthcare, need to respond appropriately to this challenge.

General practice is that component of the healthcare system which provides initial, continuing, comprehensive, co-ordinated and personalized care for individuals, families and communities.

There is an alarming incidence of heart disease in South Africa. One in three men and one in four women will suffer a heart attack before the age of 60.

Every year, more than 50,000 South Africans suffer heart attacks. Of these, 25% (12,000) die immediately.

Only Scotland, Finland and Northern Ireland have a higher heart disease mortality rate according to data from the Heart and Stroke Foundation of South Africa.

Coronary Artery Disease Statistics

The Statistics SA (2013) report indicated that cancer did not appear among the 10 most frequent causes of death. The ICD – 10 Disease Classification does not provide for an all-encompassing malignant disease category, thus making the cancer death statistics totally inaccurate. The total deaths from cancer are distributed over 15 anatomical sites with the resulting inaccurate statistics. The true figure reveals that cancer was in fact the second most frequent cause of death in SA, second only to HIV / TB.

SAMJ Feb 2015

Cancer Statistics in South Africa

The main cancer risk factors include: tobacco use, obesity, high fat diet, lack of physical activity, excessive exposure to sunlight, infectious agents and chemicals in food and the environment.

Up to 40% of cancers are said to be preventable.

Cancer Risk Factors

An estimated 70,000 South Africans are killed due to trauma every year, with a further 3.5 million seeking health care as a result of trauma.

More than 9,000 people are killed in traffic accidents every year and 33,000 are injured. 39% of those killed are pedestrians.

Substance abuse is implicated in 80% of trauma patients. Almost half of the deaths due to injury are as a result of

homicide. People, guns, knives, motor vehicles, open fires, unsafe

electrical appliances, household chemicals and medications, manual and electrically powered tools, unguarded hazards like high buildings, deep pits and open bodies of water; all these are implicated in the high trauma statistics

Trauma

Approximately 30% of Ante-natal Clinic attenders are HIV positive. The overall incidence of HIV positive people in South Africa is in the region of 10 – 12%. In the 15 – 49 year old group, 15-18% are HIV +ve. The majority of deaths due to HIV are misclassified on the death certificates, although this has improved recently. Tuberculosis incidence in HIV+ patients is extremely high. MDR and XDR TB in HIV +ve patients is proving to be a big challenge.

The high incidence of pediatric diarrheal disease and pneumonia also needs to be addressed. The new rotavirus vaccine has however decreased the incidence of diarrheal disease significantly.

The introduction of pneumococcal and haemophilus influenza vaccines, the up scaling of immunization research against measles, pertussis (whooping cough), tuberculosis and respiratory syncytial virus are all positive developments.

No slide on infection may be complete without making mention of the increasing problem of antibiotic resistant organisms.

Infections – HIV/Tuberculosis.

Vascular endothelial cells are vital in regulating blood flow through vessels and preventing intravascular thrombosis. Endothelial dysfunction is associated with most forms of cardiovascular disease, including hypertension, coronary artery disease, heart failure, peripheral vascular disease, stroke, diabetes and chronic renal failure.

Cardiovascular Disease and Endothelial Dysfunction

Risk factors for endothelial dysfunction include smoking, diabetes, elevated lipids, hypertension and infections.

Atherosclerosis refers to patches of small fatty lumps that develop within the walls of blood vessels (arteries). Patches of atheroma are often called plaques, and these plaques may cause narrowing of the arteries, which can reduce blood flow. This problem is clearly associated with dyslipidemia, but it is now known that there is an inflammatory component involved which adds to the endothelial dysfunction.

Endothelial Cell Risk Factors

The four most common modifiable risk factors include an unhealthy diet, physical inactivity, tobacco use and the excessive use of alcohol. These four risk factors can lead to hypertension, diabetes, dyslipidemia, as well as overweight and obese states.

Addressing these risk factors can help to avoid up to 80% of heart disease.

Cardiovascular Disease Risk Factors

These 4 risk factors are associated with the following four diseases i.e. cardiovascular disease, cancer, diabetes and chronic lung disease. Thus a great health impact can be achieved by addressing the risk factors

Cardiovascular Risk Factors - Continued

Stable angina: central chest discomfort or pain, usually of a crushing heavy nature, brought on by exertion and relieved by rest or sublingual nitrate.

Unstable angina: Chest pain which increases rapidly in severity and occurs at rest. This is due to sub-total coronary artery obstruction.

NSTEMI : non-ST elevation myocardial infarction. This condition is similar to unstable angina except for elevated cardiac enzymes due to sub-endocardial muscle injury.

STEMI : ST elevation myocardial infarction; this is a true heart attack. Here there is trans-mural full-thickness myocardial injury.

Recognition of Coronary Artery Disease.

Sudden onset of the following suggests a stroke (or a TIA if symptoms last less than 24 hours and resolve completely)

Signs include: Weakness, numbness or paralysis of usually one side of

the body.Blurred or decreased vision of one eye, or double

vision.Difficulty in speaking or understanding.Dizziness, loss of balance or unexplained fall, and

unsteady gait.Sudden onset of severe new headache.

Stroke – TIA (Transient Ischaemic Attack)

Patients may be asymptomatic or can present with intermittent claudication or critical limb ischaemia. Intermittent claudication patients may describe pain, lameness, discomfort, cramping or stiffness of calf muscle, or to a lesser extent thigh muscles or buttocks, with exercise. The incidence of peripheral vascular disease is 3-10% overall, rising to 15-20% over the age of 70 years.

The term critical limb ischaemia implies the presence of rest pain, ulcer or gangrene.

Peripheral Vascular Disease

In the USA, Alzheimer's disease ranks as the 4th leading cause of death in adults after heart disease and stroke.

Alzheimer's disease and vascular dementia account for more than 90% of the dementias. Incidence of dementia in the >65yrs is 6.2%; 20% over the age of 80 and 40% over the age of 90. What is known is that there is a strong association between the risk factors for cardiovascular disease and the dementias

Dementia

Sexual dysfunction is defined by the WHO as the various ways in which an individual is unable to participate in a sexual relationship as desired.

Erectile dysfunction is considered to be an independent predictor of future cardiovascular disease. It may be viewed as a manifestation of vascular and endothelial dysfunction. The incidence of erectile dysfunction:

4% : under 50 years27% : 50 -59 year group40% : 60 – 69 year group

Sexual Dysfunction

This produces a very wide range of symptoms including tiredness, breathlessness, poor appetite, nausea, passing excessive amounts of urine and swelling. The most common cause is endothelial dysfunction caused by diabetes and hypertension.

Chronic Kidney Disease

It is very difficult to do long term controlled studies on diet with a view to measuring cardiovascular endpoints. What is however known is that the Mediterranean diet reduces mortality by 25%, coronary heart disease deaths by 33% and cancer by 24%. The beneficial components include a high intake of vegetables, legumes, fruits, nuts, olive oil, cereal, fish, mono-unsaturated fats with small amounts of meat, poultry and high fat dairy products.

What is recommended is a balanced diet low in fats (particularly saturated fats and trans-fatty acids), high in fibre, low in refined carbohydrate, with plentiful vegetables and fruits.

Diet

This is essentially a very low carbohydrate, high saturated fat, high protein diet closely related to the Atkins diet. It allows more attractive foods and has good data to show weight loss and decreased insulin sensitivity, but at the cost of increasing the LDL-C. However and importantly, there has been no research measuring the long-term endpoints of cardiovascular disease from this diet.

The Banting Diet

There is good reason for concern that this diet may result in nutritional deficiencies, increased risk for heart disease, diabetes mellitus, kidney problems, constipation, certain cancers and excessive iron stores in some individuals in the long-term. Research leaves no doubt that healthy balanced eating is very important in reducing disease risk.

University of Cape Town, Faculty of Health Sciences; August 2014.

UCT Statement regarding the Banting Diet

It is therefore a serious concern that Prof Timothy Noakes, a colleague respected for his research in Sports Science, is aggressively promoting this diet as a “revolution”, making outrageous unproven claims about disease prevention, and maligning the integrity and credibility of peers who criticize his diet for being evidence-deficient and not conforming to the tenets of good and responsible science. This goes against the University of Cape Town’s commitment to academic freedom as the prerequisite to fostering responsible and respectful intellectual debate and free enquiry.

 University of Cape Town Health Sciences Statement; August 2014

UCT Statement : Continued

A recent systematic review combining the findings of 19 clinical trials in 3,209 people found that low carbohydrate diets result in similar weight losses over 2 years compared to diets containing a recommended balance of carbohydrate, fat and protein.

The review confirms that overall energy (kilojoule) intake over a period of time will result in weight loss.

Adherence to a reduced energy intake is key for successful weight loss.

The fundamental issue is not so much losing weight, but maintaining weight loss.

Association for Dietetics in South Africa, Chronic Disease Initiative for Africa, Heart and Stroke Foundation of South Africa, Nutrition Society of South Africa and Professional Board for Dietetics and Nutrition of the HPCSA July 2014

Reports from this conference indicate that there was some disagreement amongst participants at the recent congress on the issue of high saturated fat diet as advocated by Prof T Noakes

Dr Sunika Potgieter, Dietician, University of Stellenbosch Winelands Conference March 2015

BANTING CONFERENCE FEBRUARY 2015

Insufficient physical activity increases the risk of cardiovascular death by 20 – 30%. The recommendation is at least 30 minutes of moderate exercise per day at least five times per week

Exercise

Excessive salt intake is associated with hypertension. Limit salt to no more than one teaspoon per day. Avoid or limit foods that are top contributors to high salt intake including hard margarines, salty snacks, soup and gravy powders, viennas, beef sausages and meat pies.

Salt

Increased calorie intake and reduced physical activity track this pattern, with more than 70% of women and 45% of men being overweight or obese.

Obesity

Since the introduction of statins in 1987 they have become the largest selling prescription drug worldwide. The principle therapeutic benefit is to reduce the LDL-C. Every 1 mmol/L decrease in LDL-C leads to a 20% reduction in major vascular events, including coronary deaths, non-fatal myocardial infarction and stroke.

Statins

1: 500 people in South Africa have inherited hypercholesterolaemia.

If untreated, 50% of men and 15% of women will die before 60 years of age.

In addition to reducing LDL, statins also play a very important part in plaque stabilization due to anti-inflammatory action.

The criticism of statin trials by Prof Noakes that these are pharmaceutical company driven has been disproved by a comparison of all statin trials, both sponsored and un-sponsored.

Dr F Pecoraro, Cardiologist, Tygerberg Hospital Winelands Conference March 2015

The first evidence for the benefits of Aspirin was in 1974. Aspirin decreases mortality when given in acute myocardial infarction, unstable angina, and is indicated for long term secondary prevention of cardio-vascular disease.

Aspirin use in primary prevention is most beneficial in high risk individuals.

In four trials involving 48,540 patients, the relative risk reduction of myocardial infarction was 28 – 30%.

Aspirin has been shown to reduce the risk of colon cancer by 40-50%.

Aspirin should be used in most patients with diabetes, hypertension, coronary artery disease, stroke and dementia.

Aspirin

About 35% of hypertensive patients will discontinue their medication within six months. The reason for discontinuation relates to adverse side effects from these drugs.

The most common side effect is hypotension. The symptoms may be subtle and include dizziness, fatigue and tiredness.

It is thus important to carefully tailor the therapy to suit the individual patient. Using low doses of drugs in combination is a good strategy to avoid side effects.

Anti-hypertensives

This procedure was first introduced in South Africa in 1986. However, it is increasingly recognized that needless stenting

exposes patients to risk. In an emergency i.e. if the patient is having a heart attack,

angioplasty and stenting can restore blood flow to the heart and this can be life-saving. Angioplasty and stenting is considered to be the gold standard of management for restoring blood flow to that area of the heart.

In the absence of heart attack, research shows that the procedure of non-urgent interval stenting may be no better than medication, exercise and diet in preventing a heart attack.

Interval stenting decision making is best left to the clinical judgment of the cardiologist in consultation with the cardiothoracic surgeon where indicated.

Stents

This is indicated in patients with chest pain consistent with myocardial infarction and ST segment elevation on the ECG. These agents can achieve early re-perfusion in 50 -70% of patients and can thus reduce mortality and the extent of myocardial damage. This is extensively used in South Africa due to the wide non-availability of angioplasty and stenting

Thrombolytic Therapy

First introduced in South Africa in 1974, coronary bypass surgery has been considered a routine operation for more than 30 years. Bypass surgery is performed to relieve pain and also to prolong life.

In the following scenarios bypass surgery is essential and life-saving:

When the left main coronary artery is severely blocked or narrowed. If there are two or more blockages of which one is situated in the first

few cms of the left anterior descending coronary artery. If the patient has two or more coronary artery lesions and the left

ventricle is functioning poorly. If the patient has debilitating angina or chest pain because several of

the arteries which supply the heart muscle are narrowed. If the patient has a blockage that cannot be opened by means of

angioplasty, or that has reappeared after angioplasty.

Bypass Surgery

There is no doubt that the incidence of cardio-vascular disease in South Africa is alarmingly high. Much still needs to be done in addressing the risk factors which contribute to this high incidence. Both education and particularly motivation of people to appropriately address the risk factors of cardio-vascular disease is essential.

General practitioners are undoubtedly ideally placed to play a leading role in the prevention and management of cardiovascular disease.

Conclusion