Essential Hypertension 632021 1 Hypertension Hypertension is not

Essential Hypertension 6/3/2021 1

Hypertension • Hypertension is not a disease • It is an arbitrarily defined disorder to which both environmental and genetic factors contribute • Major risk factor for: – cerebrovascular disease – myocardial infarction – heart failure – peripheral vascular disease – renal failure 6/3/2021 2

This left ventricle is very thickened (slightly over 2 cm in thickness), but the rest of the heart is not greatly enlarged. This is typical for hypertensive heart disease. The hypertension creates a greater pressure load on the heart to induce the hypertrophy. 6/3/2021 3

The left ventricle is markedly thickened in this patient with severe hypertension that was untreated for many years. The myocardial fibers have undergone hypertrophy. 6/3/2021 4

• Blood pressure is a continuous variable which fluctuates widely during the day – physical stress – mental stress • The definition of hypertension has been arbitrarily set as: That blood pressure above which the benefits of treatment outweigh the risks in term of morbidity and mortality 6/3/2021 5

Blood Pressure • Exhibits a normal distribution within the population • Increasing blood pressure is associated with a progressive increase in the risk of stroke and cardiovascular disease • Risk however rises exponentially and not linearly with pressure 6/3/2021 6

At what blood pressure is a patient hypertensive? • • BHS 140/90 JNC-VI 140/90 Opt <120/<80 WHO-ISH 140/90 The current recommendation in the UK is 140/90 • However risk is important and in diabetes 130/80 6/3/2021 7

• In 95% of cases no cause can be found • In 5 -10% a cause can be found – Chronic renal disease – Renal artery stenosis – Endocrine disease, Cushings, Conn’s Syndrome, Phaeochromocytoma, GRA 6/3/2021 8

Risks of Hypertension • The risk of hypertension is considerable • The 4 th most common cause of death world-wide • Directly and indirectly responsible for >20% of all deaths • The risks of hypertension have been most thoroughly determined by the Framingham Study a longitudinal study performed in the USA 6/3/2021 9

Framingham Study • This study clearly demonstrated that the relative risk to a patient with a DBP of 99 mm. Hg compared to a DBP of 84 mm Hg for – Stroke increases 4 fold – MI increases 2 times • The same was also found to be true for systolic blood pressure • These pressure are common 6/3/2021 10

• Despite the clear relationship between blood pressure and morbidity the risk from hypertension also depends on and increases exponentially with other factors – Cigarette smoking Adds 20/10 mm. Hg – Diabetes mellitus 5 -30 X increase MI – Renal disease – Male 2 X risk – Hyperlipidaemia – Previous MI or stroke – Left ventricular hypertrophy 2 X risk 6/3/2021 11

Control of blood pressure • Blood pressure is controlled by an integrated system • Prime contributors to blood pressure are: – Cardiac output • Stroke volume • Heart rate – Peripheral vascular resistance • Each of these factors can be manipulated by drug therapy 6/3/2021 12

Sympathetic Nervous System • Sympathetic system activation produces – vasoconstriction – reflex tachycardia – increased cardiac output • In this way blood pressure is increased • The actions of the sympathetic system are rapid and account for second to second blood pressure control 6/3/2021 13

The renin-angiotensin-aldosterone system • The RAAS is pivotal in long-term BP control • The RAAS is responsible for: – maintenance of sodium balance – control of blood volume – control of blood pressure 6/3/2021 14

• The RAAS is stimulated by: – fall in BP – fall in circulating volume – sodium depletion • Any of the above stimulate renin release from the juxtaglomerular apparatus • Renin converts angiotensinogen to angiotensin I • Angiotensin I is converted to angiotensin II by angiotensin converting enzyme (ACE) 6/3/2021 15

• Angiotensin II is a potent – vasoconstrictor – anti-natriuretic peptide – stimulator of aldosterone release from the adrenal glands • Aldosterone is also a potent antinatriuretic and antidiuretic peptide • Angiotensin II is also a potent hypertrophic agent which stimulates myocyte and smooth muscle hypertrophy in the arterioles 6/3/2021 16

• Myocyte and smooth muscle hypertrophy: – are both poor prognostic indicators in patients with hypertension – partially explain why hypertension and the risks of hypertension persist in some patients despite treatment • Both the sympathetic and RAAS are key targets in the treatment of hypertension 6/3/2021 17

Aetiology of essential hypertension • The aetiology of hypertension is – Polygenic • Major genes • Poly genes – Polyfactorial • Environment • Individual and Shared 6/3/2021 18

• Likely causes: • Increased reactivity of resistance vessels and resultant increase in peripheral resistance – as a result of an hereditary defect of the smooth muscle lining arterioles • A sodium homeostatic effect – In essential hypertension the kidneys are unable to excrete appropriate amounts of sodium for any given BP. As a result sodium and fluid are retained and the BP increases 6/3/2021 19

Other factors • • • Age Genetics and family history Environment Weight Alcohol intake Race 6/3/2021 20

• AGE – BP tends to rise with age, possibly as a result of decreased arterial compliance. – Hypertension in the elderly should be treated as aggressively as in the young. They have more to lose – Studies such as EWPHE, Primary Care Study, MRC Hypertension in the Older Adult, SHEP, SYSTEUR and STOP-1 and 2 have proven that treating both diastolic and systolic hypertension in the elderly significantly reduces stoke and MI. 6/3/2021 21

• GENETICS – A history of hypertension tends to run in families – The closest correlation exists between sibs rather than parent and child – It is also possible that environmental factors common to members of the family also have a role in the development of hypertension 6/3/2021 22

• Environment – Mental and physical stress both increase blood pressure – However removing stress does nor necessarily return blood pressure to normal values – True stress responders who have very high BP when they attend their doctor but low normal pressures otherwise tend to be highly resistant to treatment 6/3/2021 23

• Sodium Intake – The SALT study and more recently the DASH study have confirmed a strong relationship between hypertension, stroke and salt intake – Reducing salt intake in hypertensive individuals does lower blood pressure – However reducing salt intake in normotensives appears to have no effect – Reducing salt intake to <1. 5 gm/day or better <0. 5 gm/day does lower BP – However there are real difficulties in achieving this level of salt restriction (fast food) 6/3/2021 24

• ALCOHOL – The most common cause oh hypertension in the young Scot – Affects 1% of the population – Small amounts of alcohol tend to decrease BP – Large amounts of alcohol tend to increase BP – If alcohol consumption is reduced BP will fall over several days to weeks. – Average fall is small 5/3 mm. Hg 6/3/2021 25

• Weight – Obese patients have a higher BP – Up to 30% of hypertension is attributable in part or wholly to obesity – If a patient loses weight BP will fall – In untreated patients a weight loss of 9 Kg has been reported to produce a fall in BP of 19/18 mm. Hg – In treated patients a fall in BP of 30/21 mm. Hg has been reported – Weight reduction is the most important nonpharmacological measure available 6/3/2021 26

Birth Weight • Birth weight is also associated with the development of hypertension in later life. • The lower the birth weight the higher the likelihood of developing hypertension and heart disease • Clearly in-utero factors affect health at a later stage. 6/3/2021 27

• Race – Caucasians have a lower BP than black populations living in the same environment – Black populations living in rural Africa have a lower BP than those living in towns – Reasons are not clear – Possibly black populations are more susceptible to stress when living in towns – Respond in different ways to changes in diet – Black populations are genetically selected to be salt retainers and so are more sensitive to an increase in dietary salt intake 6/3/2021 28

Secondary Hypertension • 5 -10% of all hypertension has an identifiable cause • Removal of the cause does not guarantee that the hypertension or risk will return to normal • Sustained hypertension produces end-organ damage to blood vessels, heart and kidney • This type of damage tends to increase BP further and so a vicious self-propagating cycle is established 6/3/2021 29

Causes for Secondary Hypertension • Renal disease – 20% of resistant hypertensive patients – chronic pyelonephritis – renal artery stenosis – polycystic kidneys • Drug Induced – NSAIDs – Oral contraceptive – Corticosteroids 6/3/2021 30

• Pregnancy – pre-eclampsia • Endocrine – Conn’s Syndrome – Cushings disease – Phaeochromocytoma – Hypo and hyperthyroidism – Acromegaly • Vascular – Coarctation of the aorta • Sleep Apnoea 6/3/2021 31

The risks of hypertension • The risks of hypertension are well recognised • Cerebrovascular disease – Thromboembolic – Intra cranial bleed – TIA • Cardiovascular disease – Myocardial infarction – Heart failure – Coronary artery disease 6/3/2021 32

The risks of hypertension • Peripheral vascular disease • Renal failure 6/3/2021 33

The risks of hypertension • A sustained increase in BP increases the load on the heart and blood vessels • This has two effects – Myocardial hypertrophy – Smooth muscle hypertrophy in the resistance vessels • Hypertrophy of this type increases the strength of the heart and vasculature • However it also reduces compliance 6/3/2021 34

• The effects of reduced compliance are: – A reduction in the ability of the heart to to respond to increased or variable loads – a decrease in the ability of the resistance vessels to relax • For the same level of BP and irrespective of age the presence of left ventricular hypertrophy increases 5 year mortality by – 33% in men – 21% in women 6/3/2021 35

• Atheromatous disease – Sustained hypertension is associated with accelerated atheromatous disease of the blood vessels – Peripheral vascular disease – Coronary artery disease – Cerebrovascular disease – Renal artery disease • The Heart – MI – Heart failure – Angina 6/3/2021 36

Detection and Diagnosis • • Initial assessment History Office blood pressure ABPM Abdominal ultrasound scan Inpatient assessment Assess risk – Smoking – Diabetes – Previous pathology 6/3/2021 37

Hypertension • Medication for High Blood Pressure – Diuretics • Rid the body of excess fluids and salt – Beta-blockers • Reduce the heart rate and the work of the heart – Calcium antagonists 6/3/2021 • Reduce heart rate and relax blood vessels 38

Hypertension • Medication for High Blood Pressure – Angiotensin II receptor blockers(ACE) • Interfere with the bodies production of angiotensin, a chemical that causes the arteries to constrict (narrow) – Vasodialators 6/3/2021 • Cause the muscle in the wall of the blood vessels to relax, allowing the vessel to 39 dialate (widen)

Hypertension • Medication for High Blood Pressure – Sympathetic nerve inhibitors 6/3/2021 • Sympathetic nerves go from the brain to all parts of the body, including the arteries • Cause arteries to constrict raising blood pressure • These drugs reduce blood pressure by inhibiting these nerves from constricting blood vessels 40

Hypertension • Home Blood Pressure Monitoring – Mercury sphygmomanometer • • • 6/3/2021 Standard for BP monitoring No calibration May be bulky Need a second person to use machine May be difficult for hearing impaired or patients with arthritis 41

Hypertension • Home Blood Pressure Monitoring – Aneroid equipment • • 6/3/2021 Inexpensive, lightweight and portable Two person operation/need stethoscope Delicate mechanism, easily damaged Needs calibration with mercury sphygmomanometer 42

Hypertension • Home Blood Pressure Monitoring – Automatic equipment • • • 6/3/2021 Contained in one unit Portable with easy-to-read digital display Expensive, fragile Must be calibrated Requires careful cuff placement 43

Treatment of Adults with Systolic-Diastolic Hypertension without Other Compelling Indications TARGET <140 mm Hg systolic and < 90 mm. Hg diastolic INITIAL TREATMENT AND MONOTHERAPY Lifestyle modification therapy Thiazide ACE-I ARB Longacting CCB Betablocker* * Not indicated as first line therapy over 60 6/3/2021 44

Summary: Treatment of Hypertension without Other Compelling Indications TARGET <140 mm Hg systolic and < 90 mm. Hg diastolic Lifestyle modification therapy Thiazide diuretic CONSIDER • Nonadherence? • Secondary HTN? • Interfering drugs or lifestyle? • White coat effect? ACE-I ARB Long-acting CCB Betablocker* Dual Combination Triple or Quadruple Therapy * Not indicated as first line therapy over 60 6/3/2021 45

Thank you for attention! 6/3/2021 46