BCR 5 - Hypertension, Cardiovascular Risk, MI and Heart Failure

What does the term hypertension mean?

Chronic condition where force of blood on artery walls is too high (High BP) (it does not necessarily refer to blood or arteries and can occur in other body compartments)

What is systemic hypertension?

Persistently high blood pressure in the general arterial system supplying the body, distinct from pulmonary circulation

What is pulmonary hypertension?

Raised pressure within the pulmonary arteries rather than the systemic circulation

What is benign intracranial hypertension?

Raised cerebrospinal fluid leading to increased pressure in brain rather than blood vessels

How is blood pressure measured clinically?

It can be measured anywhere with a prominent artery, with peripheral arm measurements best approximating aortic pressure

What device is traditionally used to measure blood pressure?

sphygmomanometer

Why is manual blood pressure measurement still important?

It is useful when electronic devices are unreliable, such as during exercise

Why is defining hypertension difficult?

Blood pressure has continuous systolic and diastolic values that vary with time and age, with no clear normal abnormal cutoff

How does blood pressure relate to cardiovascular risk?

As systolic and diastolic pressure increase, cardiovascular risk increases continuously

What are the UK and European diagnostic thresholds for hypertension?

Systolic pressure greater than 140 mmHg and or diastolic pressure greater than 90 mmHg

Why does patient context matter when interpreting blood pressure?

The same reading has different significance depending on age and comorbidities

What is considered a hypertensive emergency?

Systolic pressure above 180 mmHg and or diastolic pressure above 120 mmHg

What is white coat hypertension?

Anxiety related elevation of blood pressure during clinical measurement mediated by stress hormones

How is white coat hypertension identified?

Normal home blood pressure readings with high clinic measurements

Why is it important to distinguish white coat from true hypertension?

True hypertension requires investigation and treatment, whereas white coat hypertension does not represent sustained disease

What are the major risk factors for developing hypertension?

Ageing, obesity, physical inactivity, poor diet, alcohol intake, and high salt consumption

Why is hypertension becoming more common worldwide?

Global increases in lifestyle related risk factors

Why is the pathophysiology of hypertension complex?

It is not fully understood (likely involves multiple interacting mechanisms that differ between patients)

What does mosaic causality mean in hypertension?

Different physiological mechanisms dominate in different individuals

What are the key physiological contributors to raised blood pressure?

Increased circulating volume, increased salt, increased peripheral vascular resistance, and endothelial dysfunction

Which organ systems regulate blood pressure?

Kidneys, RAAS, central and peripheral nervous systems, autonomic nervous system, vascular endothelium, and adrenal glands

What is the renin angiotensin aldosterone system?

A hormonal cascade that regulates blood pressure, fluid balance, and vascular tone

What is the role of angiotensin II in hypertension?

It causes vasoconstriction, promotes salt and water retention, increases cardiac contractility, and drives vascular smooth muscle growth

How does RAAS affect nitric oxide?

It interferes with nitric oxide handling, reducing vasodilation

What nervous system abnormalities may contribute to hypertension?

Impaired baroreceptor responses and sympathetic nervous system overactivity

What is the relationship between sodium intake and blood pressure?

High sodium intake is associated with higher blood pressure, but evidence is mixed

How much does sodium reduction lower blood pressure on average?

Reducing sodium by 1.75 g lowers systolic pressure by about 4.2 mmHg and diastolic by about 2.1 mmHg

Does sodium reduction clearly reduce cardiovascular events?

There is no strong evidence for reduced death, stroke, or myocardial infarction

How does sodium increase blood pressure physiologically?

It causes water retention, increases blood volume, and activates renal and hormonal systems

Why can very low sodium intake be harmful?

It may activate RAAS and increase cardiovascular risk

What sodium intake is generally recommended?

Approximately 1.5 to 2.4 g per day, with some evidence supporting 3 to 6 g per day

What is meant by a J or U shaped relationship between sodium and risk?

Both very low and very high sodium intake are associated with increased risk

What role does potassium play in blood pressure control?

Potassium salts appear beneficial and sodium potassium substitution may lower blood pressure

What is the practical clinical advice regarding salt intake?

Reduce excessive intake but avoid complete elimination

What is essential hypertension?

Hypertension with no single identifiable cause, accounting for most cases

How common are secondary causes of hypertension?

Approximately 5 to 15 percent of cases

Why is it important to identify secondary hypertension?

Many secondary causes are treatable and blood pressure may normalise

Why are not all patients investigated for secondary causes?

Hypertension is common and resources require selective investigation

Which patients should raise suspicion of secondary hypertension?

Young patients, young women, resistant hypertension, or abnormal clinical findings

Why are the kidneys central to blood pressure regulation?

They control salt and water balance and both cause and suffer from hypertension

What is renal parenchymal disease?

Damage to functional kidney tissue impairing filtration and urine production

What is renovascular hypertension?

Hypertension caused by narrowing of the renal arteries

What is fibromuscular dysplasia?

A rare inherited disorder causing beaded narrowing of renal arteries leading to RAAS activation

How does renovascular disease differ in older patients?

Arterial narrowing is smoother and similar to coronary artery disease

What is the chicken and egg problem in hypertension and kidney disease?

Hypertension can cause kidney disease and kidney disease can cause hypertension

What endocrine systems commonly cause secondary hypertension?

The RAAS system and the glucocorticoid system

What is primary hyperaldosteronism or Conn’s syndrome?

Excess aldosterone production causing sodium retention, increased blood volume, and low potassium

Why does Conn’s syndrome cause hypokalaemia?

Aldosterone increases urinary potassium loss

How is Conn’s syndrome diagnosed?

By a high aldosterone to renin ratio and confirmatory imaging

What is Cushing’s syndrome?

Excess cortisol production causing RAAS activation, vasoconstriction, and hypertension

Why are Conn’s and Cushing’s syndromes clinically important?

They are relatively common, treatable, and blood pressure can normalise

What is a phaeochromocytoma?

A rare usually benign adrenal tumour producing catecholamines (excess adrenaline)

What are the classic symptoms of phaeochromocytoma?

Paroxysmal hypertension, pallor, pounding headache, perspiration, and palpitations

How is phaeochromocytoma diagnosed?

By measuring metanephrines in blood or urine

Why is hypertension in pregnancy a special consideration?

Hormonal changes and increased blood volume alter blood pressure regulation

How does blood pressure change in early pregnancy?

It often falls in the first trimester due to vasodilation and reduced venous tone

What is gestational hypertension?

New onset hypertension during pregnancy without proteinuria

What is pre eclampsia?

Hypertension with proteinuria during pregnancy that can progress to eclampsia

Why is urine protein checked in pregnancy?

To detect pre eclampsia, unlike routine care in non pregnant adults

What are monogenic causes of hypertension?

Rare single gene disorders distinct from common polygenic hypertension

What is glucocorticoid remedial aldosteronism?

A childhood condition mimicking Conn’s syndrome with early cardiovascular risk

What is glucocorticoid resistance?

Failure of ACTH cortisol feedback causing excess cortisol and severe hypertension

What is Liddle’s syndrome?

An autosomal dominant disorder with abnormal distal sodium channels causing sodium retention and low aldosterone

How common is hypertension worldwide?

It affects over 1 billion people and is the most common condition globally

What proportion of adults have hypertension?

Around one third of all adults

How common is hypertension in older adults?

Around 60 percent of people over 60 years have hypertension

How is the global burden of hypertension expected to change?

It is predicted to rise to about 1.5 billion adults by 2025

Why is hypertension considered globally important?

It is the biggest worldwide contributor to premature death

How many deaths are directly attributed to hypertension?

Approximately 10 million deaths worldwide in 2015

Which major diseases are strongly influenced by hypertension?

Ischaemic heart disease, stroke, dementia, and kidney disease

How is hypertension related to COVID 19 outcomes?

It is associated with increased mortality from COVID 19

Why does hypertension increase individual risk?

It rarely kills directly but strongly contributes to fatal vascular diseases

Which diseases are commonly caused by hypertension?

Ischaemic heart disease, stroke, peripheral arterial disease, dementia, and renal disease

What is the metabolic syndrome?

A cluster of hypertension, diabetes or insulin resistance, and obesity

Why is clustered risk worse than individual risk?

Combined risk is greater than the sum of individual risk factors

Why is it difficult to assign individual risk from blood pressure?

Blood pressure is a continuous variable with no precise risk threshold

How is cardiovascular risk estimated in hypertensive patients?

Using cardiovascular risk calculators rather than single BP values

What is the difference between relative and absolute cardiovascular risk?

Relative risk compares to peers, while absolute risk reflects actual event probability

Why can young hypertensive patients be misleadingly low risk?

They have low short term absolute risk but high lifetime cumulative risk

How does systolic blood pressure relate to cardiovascular risk?

Every 20 mmHg rise in systolic pressure roughly doubles cardiovascular risk

What benefits occur with modest blood pressure reduction?

Reduced cardiovascular events, mortality, stroke, coronary events, and heart failure

How much does lowering BP reduce major cardiovascular events?

About a 20 percent reduction with 10 mmHg systolic or 5 mmHg diastolic reduction

How does baseline risk affect BP treatment benefit?

Relative benefit is similar, but absolute benefit is greater with higher baseline risk

What is hypertension mediated organ damage?

Structural or functional organ changes caused by chronic hypertension

Which organs are affected by HMOD?

Heart, blood vessels, brain, eyes, and kidneys

Why is HMOD clinically important?

It identifies high risk patients before symptomatic disease occurs

How does hypertension affect blood vessels?

It accelerates ageing related arterial changes across all vascular beds

What structural vascular changes occur in hypertension?

Increased wall thickness, lumen narrowing, stiffness, inflammation, and calcification

How do large arteries change with hypertension?

They may dilate, become tortuous, and lose elastic recoil

What is the earliest cardiac change in hypertension?

Left ventricular hypertrophy

Why does left ventricular hypertrophy initially occur?

It is an adaptive response to normalise wall stress

How is left ventricular hypertrophy detected?

Suggested by ECG and confirmed by echocardiography

What ECG changes suggest LVH?

Increased QRS voltage and T wave inversion in lateral leads

What is concentric left ventricular hypertrophy?

Uniform inward thickening of the ventricular wall with reduced chamber size

What wall thickness is considered abnormal in hypertension?

Typically 14 to 18 mm

Why does LVH become pathological over time?

It leads to stiffness, impaired relaxation, and adverse remodelling

How does LVH affect systolic function?

Systolic contraction is usually preserved initially

How does LVH affect diastolic function?

Diastolic relaxation is impaired, making the ventricle stiff

Why does impaired relaxation raise left atrial pressure?

Higher pressure is needed to fill a stiff ventricle

What causes left atrial dilatation in hypertension?

Chronic elevation of left atrial pressure