Systemic hypertension or High Blood Pressure (HBP) is a common cardiovascular disease, which affects a large population of adults. An approximate incidence of the disease would be 12 – 18 % of adults over the age of thirty. It is a disease with minimal symptoms and often fatal complications; so much so, it has been aptly called the “silent killer”. In a country like the United States, 50 million Americans have HBP. Worldwide prevalence estimates 1 billion individuals to be hypertensive and about 7.1 million deaths per year may be attributable to this disease. Exact statistics are not available from India but the prevalence in various studies has been stated to be about 12 – 15 %. This emphasizes the magnitude of the problem and the seriousness of the disease.

The other aspect of the disease is that only a small percentage of the people are aware of the disease. Hence the disease may remain undetected for a long time or be detected only accidentally. Even those patients who are aware of the disease are not on treatment or are on inadequate dose of drugs for the disease.

Let us in brief look at the various aspects of the disease, its classification, co-morbid conditions, other risk factors that we have to look for when we diagnose HBP and the complications of the disease

Classification
Category   Systolic BP (mm. Hg)     Diastolic BP (mm. Hg)
Normal                < 120                             <80
Pre hypertension 120 - 139                        80 – 89
Stage I HBP       140 – 159                       90 – 99
Stage II HBP      ≥ 160                              ≥ 100


Other associated Risk Factors
When HBP is diagnosed, other associated risk factors for cardiovascular disease (CVD) are to be looked for in the patient by clinical examination or laboratory tests. Let us enumerate them one by one.

1. Diabetes mellitus: It is a disease most commonly associated with HBP. A combination of HBP with diabetes places a patient at an increased risk of CVD. Hence all patients with HBP should have a blood glucose test.

2. High Serum Lipids: Another risk factor for the CVD is high levels of Cholesterol and Triglyceride in blood. Hence all patients with HBP should have their serum lipid profile done to know the levels of Cholesterol and Triglyceride and if high, are to be treated appropriately.

3. Cigarette smoking: Cigarette smoking increases the risk of CVD especially myocardial infarction and stroke. When cigarette smoking is associated with other risk factors too, the risk of CVD events increase multi fold. Hence the need to advise patients to stop smoking.

4. Obesity: The Body Mass Index (BMI) is calculated by dividing the weight of the individual (in Kg.) by the square of the height (in meters). Eg. 65 Kg ⁄ 1.7 * 1.7 = 22.5 (BMI). The normal BMI ranges from 20 – 25. 25 – 30 is considered “overweight” and > 30 is called “Obesity”. Obesity is a definite risk factor for various diseases and also for CVD. Hence the need to control the weight in patients with HBP.

5. Physical Inactivity: Lack of exercise is also a risk factor for CVD and adequate regular physical exercise helps to control many risk factors like obesity, HBP, diabetes mellitus and high levels of serum lipids. All HBP patients are hence encouraged to exercise regularly.

6. Age: Men above the age of 55 and women over 65 are at increased risk of CVD. However, this is a risk factor that, unlike the other previous risk factors, cannot be modified. The importance lies in that in the elderly, all other risk factors including HBP need to be well controlled.

7. Family History: Individuals who have parents with HBP, diabetes or myocardial infarction (before age 55) are at higher risk of developing similar illnesses. Though family history is unmodifiable, individuals with a positive family history can resort to modifications in their lifestyle and control other risk factors, if any.

Target Organ Damage
High blood pressure causes complications in the form of damage to various organs and blood vessels. The chief organs targeted by HBP are the heart, brain, kidneys and eyes. Longstanding, uncontrolled HBP causes damage to one or more of these target organs leading on to complications. Often the first clinical presentation may be complication.

1. Heart: HBP produces left ventricular hypertrophy as the earliest cardiac change. This may be detected by ECG or Echocardiography. Later, severe left ventricular hypertrophy may lead on to acute left ventricular failure or congestive heart failure. Progressive coronary atherosclerosis is another complication of HBP, which may present as angina pectoris, acute myocardial infarction or as sudden death.

2. Brain: The complication of HBP on the brain leads to stroke either due to cerebral hemorrhage or due to cerebral infarction. Chronic HBP can lead to dementia.

3. Kidneys: Chronic renal failure occurs in longstanding HBP when the kidneys are damaged. This causes elevation of blood urea and creatinine levels.

4. Eye: The retina of the eye shows various changes of hypertensive retinopathy, which leads to progressive loss of vision.

How to work up a patient with High Blood Pressure?
1. First of all, establish that the patient has a HBP by recording the blood pressure at 2- 3 occasions.
2. Look for other risk factors for CVD as discussed above.
3. Look for target organ damage by clinical examination, appropriate tests like blood test, ECG, echocardiography, ophthalmoscopic examination and urinalysis.
4. Institute treatment for other risk factors and for hypertension.

Lifestyle Modification:
All patients with HBP benefit by modifying their lifestyles. In those patients where the HBP is mild, life style modification alone may be enough to reduce the HBP. In those where life style modification alone does not control HBP, or in those with very high blood pressure initially, drugs must be added to the treatment of HBP. The major aspects of Life Style Modification are as follows.

1.Regular physical exercise of which walking is the best and easiest. Other aerobic exercises like swimming, playing tennis, jogging or cycling are equally good.
2.Reduction of weight by diet control and regular exercise should form part of any regimen for life style modification. Reduction in the intake of fatty foods and high sugar containing foods should be stressed upon.
3.Reduction of salt intake to about 6 gms (1 teaspoonful) per day is advisable. A practical advice is to use minimal salt in cooking and avoid high salt foods like pickles, pappads, salted nuts, chips, tinned foods etc.
4. Alcohol should be totally avoided or restricted to the minimum as a high alcohol intake (> 2 drinks a day) increases blood pressure.
5.In addition to the control of salt, the diet should contain increased amounts of fiber, fruits and vegetables. The intake of meat and milk need to be restricted.

When life style modification alone is not enough, drugs should be added to the treatment of HBP to control the blood pressure to normal levels.

The advantage of controlling HBP has been proved in many studies where it has been shown that a good control of HBP reduces the incidence of stroke by 35 – 40 %, myocardial infarction by 20 – 25 %, and heart failure by 50 %. Hence the importance of diagnosing and treating HBP in individuals and in the general population is an important responsibility of every medical practitioner