CARDIO-VASCULAR DISEASE
(CVD)
(PREVENTIVE CARDIOLOGY)
By
Dr. Sabry Ahmed Salem
Prof. of community medicine
Environ mental health &
occupational medicine
1.ISCHAEMIC HEART DISEASE (IHD)
It is the cardiac disability, acute or chronic,
arising from reduction or arrest of blood supply
to the myocardium in association with disease
process of the coronary arterial system.
Importance (= Danger) (Public Health concern):
(A) Regarding morbidity:
-  Incidence & prevalence
* Affects younger ages
-Unsatisfactory treatment (long-tern expensive
treatment & permanent disability).
(B) Regarding mortality:
- Kills adults at the peak of their productive years.
-The leading cause of death in developed countries.
-A prominent public health problem in developing
countries ( case fatality rate).
* Epidemiology:
(A) Distribution:
I- Persons:
* Age: The incidence increase with increasing the
age (Rare before 30 ys).
* Sex: males > females (5: 1 below the age of 50
years).
* Occupation: Sedentary + Mental over activity
lead to increase the incidence.
* Social standard: High social classes increase
the incidence.
(Why? Social e.g. Diet, Smoking & pattern of life).
* Personal habits: e.g. Smoking, Diet…etc.
* Race: Not definite. The incidence increases in
races consuming high cholesterol diet.
II- Place:
- Highest incidence in Finland
- Lowest incidence in Japan (?? Dietary habits)
III-Time:
High incidence in summer months (esp.
August) (Hot humid season increase cardiac
volume load for physiological adjustment of blood
temperature).
(B) Determinants underlying factors = factors
there are multiple risk factors that lead to
development of (IHD).
Risk factors of IHD: *Definition: they are characteristics, which are
associated with an increased risk of becoming diseased.
The presence of a risk factor allows us to predict the
probability that the disease will occur.
Determination: by several ways e.g.:
1-The relative risk (RR) = Ie  In
Ie means incidence among exposed group.
Ie means incidence among non-exposed group.
I.e. R.R. is the number of times more likely exposed
people is to become diseased relative to non-exposed.
2-The. Attributable Risk (AR) = Ie –In.
I.e. A.R. is the excess incidence of disease
related to exposure.
* Interaction:
Multiplicative rather than additive (The
importance of one risk factories determined
by its multiplicative interaction with the
others).
Classification of risk factors of IHD:
I-According to the ecological approach:
- Host factors: Age, sex & Heredity.
- Agent factors: Hypertension, Hypercholesterolemia &
Dyslipidemia.
- Environmental: Smoking, Dietary habits & physical
inactivity.
II-According to the relation to pattern of life:
* Unmodifiable: Age, Sex, F.H. & Genetic susceptibility.
* Potentially modifiable: Hypertension; Smoking; Diet;
Dyslipidemia; obesity; D.M.; Physical inactivity;
Emotional Stress; Personality type; Oral contraceptives,
Hyperuricemia & minor risk factors e.g. alcohol & coffee.
Unmodifiable relative risk of IHD:
-Age: The risk increase with age increasing (Marked
after the age 40 y. and Lowest below the age of 30 y.)
-Sex (Gender): The sex ratio differs by the age of
female:
Before menopause: males / females ratio = 5: 1
After menopause: M / F ratio narrows gradually till
become equal.
-Family history of IHD: (The risk markedly increased
if both parents diseased). It is a significant risk factors in
middle age but loss its importance after the age of
retirement. (Genetic & Sharing the environment).
Potentially modifiable risk factors of IHD
* Hypertension:
The risk increased in both sexes & among
various age groups. (Some risk factors act mainly
through associated Hypertension).
* Smoking:
The risk increased 2-14 times depending on
amount & duration.
* Dyslipidemia (Hyper cholesterolemia &
Hypertriglyceridemia). The distribution of
cholesterol in various lipoprotein fractions is more
significant than the total level as a risk factor i.e.
High serum LDL & Low serum HDL cholesterol
Levels.
- Dietary habits e.g.
- High intake of saturated fats.
- High intake of calories.
- High intake of salts.
(Antioxidants especially vitamin E decrease the
oxidation of fatty acids in LDL will decrease
arterial damage & astherosclerosis).
* Diabetes Mellitus (Pre-clinical or manifest):
The increased risk is mainly through its
association with
- Hypertension.
– Obesity.
- Hypercholesterolemia.
* Obesity:
Usually associated with:
- Hypertension.
- Hypercholesterolemia.
- D.M.
* Physical inactivity (Sloth):
Occupational or recreational, may be due to the effects of
exercise on:
- Muscle tone.
- Blood pressure.
- Plasma lipids profile.
- Obesity.
- Insulin resistance.
* Emotional stress & Mental over-activity:
- The risk increased especially among professionals.
- Personality type: the risk of IHD is marked in Type “A”
behavior
- Hard working (coronary prone behavior)
- Undergoing multiple tasks; ambitious; & Competitive.
* Hyperuricemia and Gout:
Usually associated with:
- Dyslipidemia.
* Oral
- Hypertension.
- Obesity.
contraceptives:
The increasing risk is directly related to duration of use.
Significant exaggerated risk if associated with smoking.
* Other (Minor) R.F.:
- Alcohol.
- Trace elements.
- Hardness of water.
- Hypercalcemia.
- Fibrinogen. …etc.
N.B.:
- Epidemiological studies play an important role in
detection of the association between these risk factors &
IHD.
-The concept of multiple risk factors is firmly established.
- There is a direct association between the number of risk
factors and the probability of developing IHD.
* Diagnosis:
(A) Clinical manifestations:
1- A symptomatic:.
2- Angina pectoris:
3- Acute myocardial infarction (AMI):
(B) Investigations:
1- E.C.G.:
* Prevention
I-Primary prevention: Management of the potential
modifiable risk factors is valuable e.g.
* Diet control: Just adequate fats, calories, & salt.
* Avoid smoking.
* Encourage regular exercise:
- Increase functional capacity of the heart.
- Decrease some risk factors e.g. : B.P., LDL, Weight,
Smoking,
- Psychological improvement.
* Medical supervision of:
- Diabetics. - Hyperuricemic & Gouty patients.
- Obese.
- Contraceptive pill users.
II-Secondary prevention:
Measures for patients after an attack of the disease:
*Diet therapy: (Low);
- Fat
- Calories in diet.
- Salt.
* Regulation of activities & life-style.
* Drug control of:
- Hypertension.
- D.M.
- Hyperuricemia.
- Ht. Disease (B-blockers).
* Medical supervision & check-up.
III-Tertiary prevention (Cardiac Rehabilitation):
This is achieved through a program of exercise
and patient education, aiming at:
- Improving functional capacity of the patient.
- Decreasing activity related symptoms.
- Enabling the patient to return to a satisfying
role.
* Control:
The basic lines of this program include:
(A) Early case finding: Through:
* Clinical
hospitals.
service
in
outpatient
clinics
&
* Routine medical examination:
-Pre-employment
examination
examination.
-Army recruiting examination
examination
-Pre-natal
-Pre-marital
* Survey studies & screening tests (E.C.G.).
(B) Proper management of cases.
(C) Health education:
Concise knowledge about the nature & risk
factors of the disease mainly directed towards:
- The public.
- Susceptible subjects.
- Health team responsible for case finding & health
education of patient.
(D) Epidemiological studies:
Aiming at:
- Detection of the prevalence of the disease.
- Detection of the characteristic epidemiological features.
- Detection of the high risk factors.
- Detection of the high-risk groups.
- Evaluating the control measures.
2- HYPERTENSION
Magnitude of the problem:
Arterial hypertension is a frequent, world – wide
health disorder.
Incidence:
The concept of incidence has limited value in
hypertension because of:
1. The variability of consecutive readings in
individuals,
2. The ambiguity of what is normal blood
pressure, and
3. The insidious nature of the condition.
Prevalence:
- In some industrialized countries, up to 25 percent of
adults have diastolic pressures above 90 mm Hg.
- Prevalence in the developing countries ranging from 10 to
20 per cent among adults.
- Only a few populations, either living at high altitudes or
belonging to primitive cultures (e.g. some areas in Asia,
Africa and South America) seems to have exceptionally
low levels of blood pressure.
- The prevalence of hypertension is higher among blacks
than whites; it increases with age in all groups.
- Hypertension is more common in men than in women up
to approximately age 50, after that time, hypertension is
more common in women.
Mortality:
- High blood pressure is a major risk factor for stroke,
CHD, heart or kidney failure. The higher the pressure,
the greater the risk and lower the expectation of life.
- Mortality rates from hypertension are misleading as
hypertension is a grossly under reported factor in
cardiovascular mortality.
- The bulk of mortality associated with hypertension is
due to cardiovascular disease. In Japan and Taiwan
and India death from stroke in more common.
- Mortality has shown largest decline in some countries
(e.g. England & Wales) during the last two decades,
this is attributed to the use of more effective drugs
introduced during the 15-20 years to control
hypertension.
Risk factors for hypertension:
(I) Non – modifiable risk factors:
Age:
Blood pressure rises with age in both sexes
and the rise are greater in those with higher initial
blood pressure. This has been attributed to
heredity, greater calorie and often-salt intake, and
an accumulation of environmental stress.
b) Genetic factors:
- Blood pressure levels are determined in part
by genetic factors.
- Family studies have shown that the children of
two normotensive parents have 3 per cent
possibility of developing hypertension, where as
this possibility is 45 per cent in children of two
hypertensive parents. A blood pressure level
among first-degree adult relatives has also been
noted to be statistically significant.
(II) Modifiable risk factors:
a) Obesity: the greater the weight gain, the
greater the risk of blood pressure. Also, when
people with blood pressure lose weight, their
blood pressure generally decreases.
b) Salt intake:
- High sodium intake (i.e. 7-8 gm per day) increases blood
pressure proportionately, and low sodium intake has
been found to lower blood pressure. It has been
postulated that essential hypertensives have a genetic
abnormality of the kidney, which makes salt excretion
difficult except at raised levels of arterial pressure.
- Potassium supplements have been found to lower
blood pressure of mild to moderate
hypertensives.
- Other cations such as calcium, cadmium and
magnesium have also been suggested as of
importance in reducing blood pressure levels.
c) Saturated fat: saturated fat raises blood
pressure as well as serum cholesterol.
d) Physical activity: physical activity reduces
blood pressure by an indirect effect.
e) Environmental stress:
- The term hypertension implies a disorder initiated
by tension or stress.
- Psychosocial factors operate through mental
processes, consciously or unconsciously to
produce hypertension.
- It has been found that nor adrenaline levels were
higher in young hypertensives than in
normotensive subjects. This supports that over
activity of the sympathetic nervous system has
an important part to play in the pathogenesis of
hypertension.
f) Alcohol: High alcohol intake is associated with an
increased risk of high blood pressure, but blood pressure
return to normal with abstinence.
g) Other factors: oral contraception (estrogen
preparations), noise, vibration, temperature and humidity
are the commonest causes of secondary hypertension.
Prevention of hypertension:
The low prevalence of hypertension in some countries
indicates that hypertension is potentially preventable. The
following approaches in the prevention of hypertension are
recommended:
1- Primary prevention:
Primary prevention has been defined as “all
measures to reduce the incidence of disease in a
population by reducing the risk of onset”. The
earlier the prevention starts the more likely it is to
be effective.
a) Population strategy:
-This is directed at the whole population, irrespective
of individual risk levels.
-It is bases on the fact that even a small reduction in
the average blood pressure of a population would
produce a large reduction in the incidence of
cardiovascular complications such as stroke and
CHD.
-The goal is to shift the community distribution of blood pressure
towards lower levels or biological normality.
- This involves the following non pharmacotherapeutic
interventions:
1- Nutrition:
- Reduction of salt intake (not more than 5g per day).
- Moderate fat intake.
- The avoidance of a high alcohol intake.
2- Weight reduction: Prevention and correction of obesity
(Body Mass Index greater than 25).
3- Exercise promotion:
Regular physical activity should be encouraged (it leads to
a fall in body weight, blood lipids and blood pressure).
4- Behavioral changes:
Reduction of stress & the avoidance of
smoking and modification of personal life style.
5- Health education:
-The whole community must be made aware of
the problem and the possibility of primary
prevention.
-The general publics require preventive advice on
all risk factors and the related health behavior.
b) High risk strategy:
- The aim is to prevent the attainment of level of
blood pressure at which the treatment would be
considered.
- It is appropriate if the risk factors occur with very
low prevalence in the community.
- Detection of high – risk subjects should be
encouraged by the optimum use of clinical
methods. Family history of hypertension and
tracking of blood pressure from child hood may
be used to identify individuals at risk.
(II) Secondary prevention:
The goal of secondary prevention is to detect and control
high blood pressure in affected individuals, and
consequently reduce the risk of morbidity and mortality
from coronary, cerebrovascular and kidney disease.
Control measures:
a) Early case detection:
- Our aim should be to identify and treat asymptomatic
hypertension before organ damage occurs.
- The only effective method is to screen the population for
hypertension, linked to follow up and sustained care.
- In Europe, the large majority of people have at least one
contact in every 2 years with the health service; the bulk
of the problem of those in need of intervention is solved.
b) Treatment:
- The aim of treatment should be to obtain a blood
pressure below 140/90.
- Modern anti-hypertensive drug therapy.
- Attention to other risk factors such as smoking and
elevated blood cholesterol levels.
c) Patient compliance:
Patient compliance is defined as the extent to which
patient behavior (in terms of taking medicines,
following diets or executing other life–style
changes) coincides with clinical prescription.
-The compliance rates can be improved through:
- Education directed to patients, families, and the
community.
- Choice of simpler, less costly drug regimens with
fewer associated adverse effects.
- Direct involvement of patients in their own care
by having them measure and record their own
blood pressure.