What Is Blood Pressure?

Blood pressure measures the pressure of the blood in arteries.

Arteries are groups of tubes which carry blood from your heart to the rest of your body.

The arteries can automatically contract (get smaller) or expand (get bigger).

When arteries contract, the pressure inside becomes higher. When arteries expand, the pressure inside becomes lower.

If arteries remain contracted or become clogged, the condition called hypertension or high blood pressure results.

How Is Blood Pressure Measured?

A blood pressure reading consists of two numbers: systolic and diastolic.

Systolic refers to systole, the phase when the heart pumps blood out into the aorta.

Diastolic refers to diastole, the resting period when the heart refills with blood.

At each heartbeat, blood pressure is raised to the systolic level, and, between beats, it drops to the diastolic level.

Hypertension is defined as systolic blood

pressure (SBP) of 140 mmHg or greater,

diastolic blood pressure (DBP) of

90 mmHg or greater, or taking

antihypertensive medication.

VI JNC, 1997

Types of hypertension

Essential hypertension

90%

No underlying cause

Secondary hypertension

Underlying cause

Causes of Secondary Hypertension

Renal Congenital anomalies, pyelonephritis, renal artery obstruction, acute and chronic glomerulonephritis Reduced blood flow to kidney causes release of renin. Renin reacts with serum protein in liver Coarctation of aorta

EndocrinePheochromocytoma Adrenal cortex tumors Cushing’s syndrome Hyperthyroidism

Medications such as estrogens, sympathomimetics, antidepressants, NSAIDs, steroids, Amphetamines

Neurogenic Miscellaneous

Identifiable Causes of Hypertension

1. Sleep apnea Drug-induced 2. Chronic kidney disease 3. Primary aldosteronism Renovascular disease 4. Chronic steroid therapy and Cushing’s syndrome 5. Pheochromocytoma6. Coarctation of the aorta 7. Thyroid or parathyroid disease

Hypertension: Predisposing factors

Age > 60 years Sex (men and

postmenopausal women) Family history of

cardiovascular disease Smoking High cholesterol diet High intake of alcohol

Sedentary life style Too much salt in the diet Stress Chronic kidney disease Co-existing disorders

such as diabetes, obesity and hyperlipidaemia Adrenal and thyroid disorders

Causes Hypertension

The exact causes of hypertension are not known. Several factors and conditions may play a role in its development, including:

The old renin-angiotensin-aldosterone system...

1999 WHO-ISH Guidelines :Definitions and Classifications of BP Levels

SBP DBP

Category* (mm Hg) (mm Hg)

Optimal < 120 < 80

Normal < 130 < 85

High-normal 130-139 85-89

Grade 1 hypertension (mild) 140-159 90-99

Borderline subgroup 140-149 90-94

Grade 2 hypertension (moderate) 160-179 100-109

Grade 3 hypertension (severe) > 180 > 110ISH > 140 < 90 Borderline subgroup 140-149 < 90

WHO-ISH Guidelines Subcommittee J Hypertens 1999; 17:151

JNC-VI, 1997

Optimal: <120 / and <80Normal: <130 / and <85High-Normal: 130-139 / or 85-89Stage I: 140-159 / or 90-99Stage II: 160-179 / or 100-109Stage III: ≥180 / or ≥110

Definitions thankfully simplified

JNC-VII, 2003JNC-VII, 2003 NORMAL: <120/ and <80 Pre-Hypertension: 120-139/ or 80-89 Stage I: 140-159 / or 90-99 Stage II: >160 / or ≥100-109

1999 WHO-ISH Guidelines:Stratification of risk to Quantify Prognosis

Degree of hypertension (mm Hg)

Risk factors and Grade 1-mild Grade 2-moderate Grade3-severe

disease history (SBP 140-159 (SBP 160-179 (SBP > 180

or DBP 90-99) or DBP 100-109) or DBP > 110)

I No other risk Low risk Med risk High risk

factors

II 1-2 risk factors Med risk Med risk Very high risk

III > 3 risk factors or High risk high risk Very high risk

target organ disease

or diabetes

IV Associated Very high risk Very high risk Very high risk

Clinical conditions

WHO-ISH Guidelines Subcommittee J Hypertens 1999;17:151

CLINICAL MANIFESTATIONS

There are usually no symptoms or signs of hypertension.

In fact, nearly one-third of those who have it don't know it.

The only way to know if you have hypertension definitely is to have your blood pressure checked

May cause headache, dizziness, blurred vision when greatly elevated BP readings more than 140/90 mm of Hg

DIAGNOSTIC EVALUATION

ECG Chest X-ray Proteinuria, elevated serum blood urea nitrogen (BUN), and creatinine levels Serum potassium Urine (24-hour) for

catecholamines Renal scan Renal duplex imaging Outpatient ambulatory BP measurements

Diseases Attributable to Hypertension

HYPERTENSION

Gangrene of the Lower Extremities

Heart Failure

Left Ventricular Hypertrophy Myocardial

Infarction

Hypertensive Encephalopathy

Aortic Aneurym

Blindness

Chronic Kidney Failure

Stroke Preeclampsia/Eclampsia

Cerebral Hemorrhage

Coronary Heart Disease

Adapted from Dustan HP et al. Arch Intern Med. 1996; 156: 1926-1935

Health Problems Are Associated With Hypertension

1. Atherosclerosis: Blood vessel damage occurs through arteriosclerosis in which smooth muscle cell proliferation, lipid infiltration, and calcium accumulation occur in the vascular epithelium Damage to heart, brain, eyes, and kidneys is termed target organ disease

2. Heart Disease: heart failure (the heart can't adequately pump blood),

3. ischemic heart disease (the heart tissue doesn't get enough blood),

4. and hypertensive hypertrophic cardiomyopathy (enlarged heart) are all associated with high blood pressure.

1. Kidney Disease: Hypertension can damage the blood vessels and filters in the kidneys, so that the kidneys cannot excrete waste properly

2. Stroke: Hypertension can lead to stroke, either by contributing to the process of atherosclerosis (which can lead to blockages and/or clots), or by weakening the blood vessel wall and causing it to rupture.

3. Eye Disease: Hypertension can damage the very small blood vessels in the retina.

1999 WHO-ISH Guidelines: Desirable BP Treatment Goals

Optimal or normal BP (< 130/85 mm Hg) for Young patientsMiddle-age patientsDiabetic patients

High-normal BP (< 140/90 mm Hg) desirable for elderly patients

Aggressive BP lowering may be necessary in patients with nephropathy, chronic renal failure, particularly if proteinuria is

< 1 g/d - 130/80 mm Hg> 1 g/d - 125/75 mm Hg

Significant benefits from intensive BP reductionin diabetic patients

24.4

18.6

11.9

0

5

10

15

20

25

30

< 90 mm Hg < 85 mm Hg < 80 mm Hg (targetDBP)

Major CV events / 100 patient-yr

Lancet 1998, 351, 1755

Relative risks of specific types of clinical complicationsrelated to tight and less tight BP Control

Patients with Absolute risk aggregate (events/1000 and points patients-yr)

Tight Less tight Less RR forcontrol control Tight tight tight control

Clinical end point (n=758) (n=390) control control p (95% Cl)Any diabetes-related 259 170 50.9 67.4 0.0046 0.76 (0.62-0.92)end pointDeaths related to 82 62 13.7 20.3 0.019 0.68 (0.49-0.94)diabetesAll cause mortality 134 83 22.4 27.2 0.17 0.82 (0.63-1.08)Myocardial infarction 107 69 18.6 23.5 0.13 0.79 (0.59-1.07)Stroke 38 34 6.5 11.6 0.013 0.56 (0.35-0.89)Peripheral vascular 8 8 1.4 2.7 0.17 0.51 (0.19-1.37)disease

Microvascular disease 68 54 12.0 19.2 0.0092 063 (0.44-0.89)

Ref : UK Prospective Diabetes Study Group BMJ 1998; 317:703

Life style modifications

Lose weight, if overweight

Limit alcohol intake

Increase physical activity

Reduce salt intake

Stop smoking

Limit intake of foods rich in fats and cholesterol

Discourage excessive consumption of coffee and

other caffeine-rich products.

Diet

A healthy diet, such as the DASH (Dietary Approaches to Stop Hypertension) diet, is very effective at lowering high blood pressure. The DASH diet calls for a certain number of daily servings from various food groups, including fruits, vegetables, and whole grains. The following steps can also help: Eating more fruits, vegetables, and low-fat dairy foods

Eating less of foods that are high in saturated fat and cholesterol, such as fried foods Eating more whole grain products, fish, poultry, and nuts Eating less red meat and sweets Eating foods that are high in magnesium, potassium, and calcium

Factors affecting choice of antihypertensive drug

The cardiovascular risk profile of the patient

Coexisting disorders

Target organ damage

Interactions with other drugs used for concomitant conditions

Tolerability of the drug

Cost of the drug

Drug therapy for hypertension

Class of drug Example Initiating dose Usualmaintenance dose

Diuretics Hydrochlorothiazide 12.5 mg o.d. 12.5-25 mg o.d.

-blockers Atenolol 25-50 mg o.d. 50-100 mg o.d.

Calcium Amlodipine 2.5-5 mg o.d. 5-10 mg o.d.channelblockers

-blockers Doxazosin 1 mg o.d. 1-8 mg o.d.

ACE- inhibitors Lisinopril 2.5-5 mg o.d. 5-20 mg o.d.

Angiotensin-II Losartan 25-50 mg o.d. 50-100 mg o.d.receptor blockers

Diuretics

Example: Hydrochlorothiazide

Act by decreasing blood volume and cardiac output Decrease peripheral resistance during chronic therapy Drugs of choice in elderly hypertensivesDrawbacks Hypokalaemia Hyponatraemia Hyperlipidaemia Hyperuricaemia (hence contraindicated in gout) Hyperglycaemia (hence not safe in diabetes) Not safe in renal and hepatic insufficiency

Beta blockers

Example: Atenolol Block 1 receptors on the heart Block 2 receptors on kidney and inhibit release of renin Decrease rate and force of contraction and thus reduce

cardiac output Drugs of choice in patients with co-existent coronary

heart disease

Drawbacks Adverse effects: lethargy, impotency, bradycardia Not safe in patients with co-existing asthma and diabetes Have an adverse effect on the lipid profile

Calcium channel blockers

Example: Amlodipine Block entry of calcium through calcium channels Cause vasodilation and reduce peripheral

resistance Drugs of choice in elderly hypertensives and

those with co-existing asthma Neutral effect on glucose and lipid levels

Drawbacks Adverse effects: Flushing, headache, Pedal

edema

ACE inhibitors

Example: Lisinopril, Enalapril Inhibit ACE and formation of

angiotensin II and block its effects Drugs of choice in co-existent diabetes

mellitus

Drawbacks Adverse effect: dry cough, hypotension,

angioedema

Angiotensin II receptor blockers

Example: Losartan

Block the angiotensin II receptor and inhibit effects of angiotensin II

Drugs of choice in patients with co-existing diabetes mellitus

Drawbacks

Adverse effect: dry cough, hypotension, angioedema

Alpha blockers

Example: Doxazosin Block -1 receptors and cause vasodilation Reduce peripheral resistance and venous

return Exert beneficial effects on lipids and insulin

sensitivity Drugs of choice in patients with co-existing

hyperlipidaemia, diabetes mellitus and BPH

Drawbacks Adverse effects: Postural hypotension

Antihypertensive therapy:Side-effects and Contraindications

Class of drugs Main side-effects Contraindications/Special Precautions

Diuretics Electrolyte imbalance, Hypersensitivity, Anuria(e.g. Hydrochloro- total and LDL cholesterol thiazide) levels, HDL cholesterol

levels, glucose levels, uric acid levels

-blockers Impotence, Bradycardia, Hypersensitivity, (e.g. Atenolol) Fatigue Bradycardia, Conduction

disturbances, Diabetes,Asthma, Severe cardiacfailure

Class of drug Main side-effects Contraindications/ Special

Precautions

Calcium channel blockers Pedal edema, Headache Non-dihydropyridine(e.g. Amlodipine, CCBs (e.g diltiazem)– Diltiazem) Hypersensitivity,

Bradycardia, Conductiondisturbances, Congestive heartfailure, Left ventriculardysfunction.Dihydropyridine CCBs–

Hypersensitivity

-blockers Postural hypotension Hypersensitivity(e.g. Doxazosin)

ACE-inhibitors Cough, Hypertension, Hypersensitivity, Pregnancy,(e.g. Lisinopril) Angioneurotic edema Bilateral renal artery stenosis

Angiotensin-II receptor Headache, Dizziness Hypersensitivity, Pregnancy,blockers (e.g. Losartan) Bilateral renal artery stenosis

Antihypertensive therapy: Side-effects and Contraindications (Contd.)

Choosing the right antihypertensive

Condition Preferred drugs Other drugs Drugs to be that can be used avoided

Asthma Calcium channel -blockers/Angiotensin-II -blockersblockers receptor blockers/Diuretics/

ACE-inhibitors

Diabetes -blockers/ACE Calcium channel blockers Diuretics/mellitus inhibitors/ -blockers

Angiotensin-IIreceptor blockers

High cholesterol -blockers ACE inhibitors/ Angiotensin-II -blockers/levels receptor blockers/ Calcium Diuretics

channel blockers

Elderly patients Calcium channel -blockers/ACE- (above 60 years)blockers/Diuretics inhibitors/Angiotensin-II

receptor blockers/- blockers

BPH -blockers -blockers/ ACE inhibitors/

Angiotensin-II receptor

blockers/ Diuretics/

Calcium channel blockers

Limitations on use of antihypertensives in patientswith coexisting disorders

Coexisting Diuretic -blocker ACE All CCB -blockerDisorder inhibitor antagonist

Diabetes Caution/x Caution/x

Dyslipidaemia x x

CHD

Heart failure /Caution Caution

Asthma/COPD x /Caution

Peripheral Caution Caution Caution vasculardisease

Renal artery x x stenosis

Effect of various antihypertensives on coexisting disorders

Total LDL- HDL- Serum Glucose Insulincholesterol cholesterol cholesterol triglycerides tolerance sensitivity

Diuretic

-blockers - - -

ACEinhibitors - - - -

Allantagonists - - - -

CCBs - - - - - -

-blockers

Combination therapy for hypertension – Recommended by JNC-VI guidelines and 1999 WHO-ISH guidelines

With any single drug, not more than 25–50% of hypertensives achieve adequate blood pressure control

J Hum. Hypertens 1995; 9:S33–S36

For patients not responding adequatelyto low doses of monotherapy

Increase the dose of drug. This, however, may lead to

increased side effects

Substitute with another drug from a different class

Add a second drug from a different class

(Combination therapy)

Add second drug from different class (Combination therapy)

If inadequate response obtained

Advantages of fixed-dosecombination therapy

Better blood pressure control

Lesser incidence of individual

drug’s side-effects

Neutralisation of side-effects

Increased patient compliance

Lesser cost of therapy

Fixed-dose combinations as recommended byJNC-VI (1997) guidelines and 1999 WHO-ISH guidelines

Calcium channel blocker and -blocker(e.g. Amlodipine and Atenolol)

Calcium channel blocker and ACE-inhibitor (e.g. Amlodipine and Lisinopril)

ACE-inhibitor and Diuretic (e.g. Lisinopril and Hydrochlorothiazide)

-blocker and Diuretic (e.g. Atenolol and Hydrochlorothiazide)

0

50

100

150

200

Systolic Diastolic

Basal Week 4

Blo

od P

ress

ure

(mm

Hg)

Reduces BP effectively

Safe and well tolerated Adverse events were reported in 7.9% of patients Common side effects included edema, fatigue and headache

Indian Practitioner 1997; 50: 683-688.

0

10

20

30

40

50

60

70

80

90

% r

espo

nder

s175.4+19.4

143.8+ 13.2

106.8+ 10.5 88.2

+ 7.6

80.5%

Efficacy and Tolerability of a fixed-dose combination of amlodipine andatenolol (Amlopres-AT) in Indian Hypertensives (n=369)

Efficacy and Tolerability of combined amlodipine andlisinopril (Amlopres-L) in Indian hypertensives (n=330)

0

50

100

150

200

Systolic Diastolic

Basal Week 4

Blo

od P

ress

ure

(mm

Hg)

Reduces BP effectively

Safe and well tolerated Adverse events were reported in 9.7% of patients Side effects commonly reported included cough and edema Only 1.76% of patients withdrew from the study.

Indian Practitioner 1998; 51: 441-447.

0

10

20

30

40

50

60

70

80

90

% r

espo

nder

s

175.4+19.4

143.8+ 13.2 106.8

+ 10.5 88.2+ 7.6

77.65

Drugs in special conditions

Condition

Pregnancy

Coronary heart disease

Congestive heart failure

Preferred Drugs

Nifedipine, labetalol, hydralazine, beta-blockers, methyldopa, prazosin

Beta-blockers, ACE inhibitors, Calcium channel blockers

ACE inhibitors,beta-blockers

1999 WHO-ISH guidelines

BEST MANAGEMENT OF HYPERTENSION

To use the fewest drugs at the lowest doses while encouraging the patient to maintain lifestyle changes.

After BP has been under control for at least 1 year, a slow, progressive decline in drug therapy can be attempted.

However, most patients need to resume medication within 1 year.

Summary

Hypertension is a major cause of morbidity and mortality, and needs to be treated

It is an extremely common condition; however it is still underdiagnosed and undertreated

Hypertension is not controlled with monotherapy in at least 50% of patients; in these patients combination therapy is required

ISOLATED SYSTOLIC HYPERTENSION

Systolic BP elevation in the absence of elevated diastolic BP is termed isolated systolic hypertension

Definitions

Hypertensive Crisis Urgency or Emergency

Hypertensive Urgency

“Severe elevation of blood pressure” Generally DBP >115-130 No progressive end organ damage

Hypertensive Emergency

“Severe elevation of blood pressure” Generally occurs with DBP >130 WITH significant or progressive end organ damage

• Hypertensive Encephalopathy• CVA – Ischemic versus hemorrhagic• Acute Aortic Dissection• Acute LVF with Pulmonary Edema• Acute MI / Unstable Angina• Acute Renal Failure• Eclampsia

Urgency vs. Emergency

Urgency No need to acutely lower blood pressure May be harmful to rapidly lower blood pressure Death not imminent

Emergency Immediate control of BP essentialImmediate control of BP essential Irreversible end organ damage or death within Irreversible end organ damage or death within

hourshours