HYPERTENSION

DR. M. SofiMD; FRCP (London); FRCPEdin; FECSEdin

Hypertension is defined as a systolic blood pressure (SBP) of 140 mm Hg or more, or a diastolic blood pressure (DBP) of 90 mm Hg or more, or taking antihypertensive medication.

Classification of BP for adults aged 18 years or older: Normal: Systolic lower than 120 mm Hg, diastolic lower than

80 mm Hg Prehypertension: Systolic 120-139 mm Hg, diastolic 80-89 mm Hg Stage 1: Systolic 140-159 mm Hg, diastolic 90-99 mm Hg Stage 2: Systolic 160 mm Hg or greater, diastolic 100 mm Hg

or greater

HYPERTENSION

Classification: Defining normal blood pressure, prehypertension, hypertension (stages I and II), and isolated systolic hypertension.

Classification Systolic pressure

Diastolic pressure

mmHg mmHg

Normal 90–119 60–79

Prehypertension 120–139 81–89

Stage 1 140–159 90–99

Stage 2 ≥160 ≥100

Isolated systolic hypertension

≥140 <90

Stage 1 140–159 90–99

Source: American Heart Association (2003).

Malignant (accelerated) hypertension: Characterized by severe hypertension (e.g. systolic >200 mm Hg, diastolic >130 mm Hg) accompanied by encephalopathy or nephropathy, or by papilloedema and/or angiopathic haemolytic anaemia.

Suspected Pheochromocytoma: Consider if there is labile or postural hypotension, headache, palpitations, pallor and profuse sweating.

Hypertensive crisis: (SBP) ≥180 mm Hg or a (DBP) ≥120 mm Hg is considered a 'hypertensive crisis'. Immediate reduction in BP is required only in patients with acute end-organ damage.

Systolic or diastolic pressure: Framingham study and the Multiple Risk Factor Intervention Trial (MRFIT) study

indicates that systolic pressure is the most important determinant of cardiovascular risk.

Other considerations

The evaluation of hypertension involves: Accurate measuring of BP Focused medical history Physical examination Routine laboratory studies. A 12-lead electrocardiogram.

Confirmation of an elevated blood pressure (at 3 separate occasions); detailed history should extract the following information:

1. Extent of end-organ damage (e.g., heart, brain, kidneys, eyes)

2. Assessment of patients’ cardiovascular risk status

3. Exclusion of secondary causes of hypertension

EVALUATION: HYPERTENSION

Assessment end organ damage:

Heart: left ventricular hypertrophy, angina/previous myocardial infarction, previous coronary revascularization, and heart failure

Brain: stroke or transient ischemic attack dementia

Chronic kidney disease

Peripheral arterial disease

Retinopathy

EVALUATION: HYPERTENSION

Age – Advancing age is associated with HTN

Obesity – Obesity and weight gain are major risk factors.

Family history – HTN is about twice as common in subjects who have one or two hypertensive.

Race – HTN tends to be more common, be more severe, occur earlier in life, in blacks.

Reduced nephron number –may predispose to hypertension.

High Sodium intake (e.g., >3000 mg/day) increases the risk for hypertension

Excessive alcohol consumption

Physical inactivity – may increases the risk for hypertension

Diabetes and dyslipidemia

Personality traits and depression

Hypovitaminosis D

Risk factors for primary (essential) hypertension 

Hypertension: component of metabolic syndrome

Tobacco use, cigarettes, including chewing tobacco

Elevated LDL cholesterol (or total cholesterol ≥240 mg/dL) or low HDL cholesterol: component of metabolic syndrome

Diabetes mellitus: component of metabolic syndrome

Obesity (BMI ≥30 kg/m2): component of metabolic syndrome

Age greater than 55 years for men or greater than 65 years for women:

Estimated glomerular filtration rate less than 60 mL/min

Microalbuminuria Family history of

premature cardiovascular disease (men < 55 years; women < 65 years)

Lack of exercise

Cardiovascular risk factors

One or more of these criteria qualifies as hypertension:

A 24-hour average of 130/80 mmHg or above

Daytime (awake) average of 135/85 mmHg or above

Nighttime (asleep) average of 120/70 mmHg or above

PRIMARY (ESSENTIAL) HYPERTENSION:

The pathogenesis of primary hypertension (formerly called "essential" hypertension) is poorly understood but is most likely the result of

Genetic and environmental factors that have multiple compounding effects on cardiovascular and renal structure and function.

Diagnosis of HTN is made using ambulatory blood pressure monitoring (ABPM) or home blood pressure monitoring.

Prescription or over-the-counter medications:

Oral contraceptives, particularly those containing higher doses of estrogen,

NSAIDs, particularly chronic use

Antidepressants, including tricyclic antidepressants and SSRI’s

Glucocorticoids Decongestants

pseudoephedrine

Weight loss medications Erythropoietin Cyclosporin Stimulants:

methylphenidate and amphetamines

Illicit drug: Drugs such as methamphetamines and cocaine can raise blood pressure

SECONDARY OR CONTRIBUTING CAUSES OF HYPERTENSION 

Secondary hypertension is commonly caused by renal disease or pregnancy.

Renal disease - approximately 75% are from intrinsic renal disease: glomerulonephritis, polyarteritis nodosa, systemic sclerosis, chronic pyelonephritis, or polycystic kidneys.

Approximately 25% are due to renovascular disease - most frequently atheromatous (e.g. elderly cigarette smokers with peripheral vascular disease) or fibromuscular dysplasia (more common in younger females).

SECONDARY OR CONTRIBUTING CAUSES OF HYPERTENSION 

Endocrine disease: Cushing's syndrome Conn's syndrome Pheochromocytoma Acromegaly Hyperparathyroidism

CoarctationPre-eclampsia and

hypertension in pregnancy.

Drugs and toxins, e.g. alcohol, cocaine, ciclosporin, tacrolimus, erythropoietin, adrenergic medications, decongestants containing ephedrine and herbal remedies containing licorice.

SECONDARY OR CONTRIBUTING CAUSES OF HYPERTENSION 

Medical history

• Duration and classification of hypertension

• Patient history of CVD

• Family history

• Symptoms suggesting causes of hypertension

• Lifestyle factors

• Current and previous medications

• Duration and classification of hypertension

Physical examination

• BP readings (2 or more), including the standing position

• Verification in contralateral arm

• Height, weight, and waist circumference

• Funduscopic examination for hypertensive retinopathy

• Exam. neck, heart, lungs, A/S for target organ damage

• BP readings (2 or more), including the standing position

Medical history and physical examination

LVH: is a common and early finding in patients with hypertension.

LVH is associated with a higher incidence of subsequent heart failure, myocardial infarction, sudden death, and stroke

Heart failure: both systolic (reduced ejection fraction) and diastolic (preserved ejection fraction), increases with the degree of blood pressure elevation.

Ischemic stroke: HTN is the most common and most important risk factor for ischemic stroke, the incidence of which can be markedly reduced by effective antihypertensive therapy

COMPLICATIONS OF HYPERTENSION 

Hypertension is the most important risk factor for the development of intracerebral hemorrhage.

Hypertension is a leading risk factor for IHD, including myocardial infarction and coronary interventions.

Chronic kidney disease and end-stage renal disease.

It can both directly cause kidney disease, which is called hypertensive nephrosclerosis, and accelerate the progression of a variety of other renal diseases

COMPLICATIONS OF HYPERTENSION 

Electrolytes and serum creatinine (to calculate the estimated glomerular filtration rate)

Fasting glucose Urinalysis Lipid profile (total and

HDL-cholesterol, triglycerides)

Electrocardiogram (ECG)

Additional tests may be indicated in certain settings:

Increased albuminuria is increasingly recognized as an independent risk factor for cardiovascular disease.

Echocardiography is a more sensitive means of identifying the presence of left ventricular hypertrophy (LVH) than an ECG

Laboratory testing

GENERAL CLINICAL CLUES:

Severe or resistant hypertension

Acute rise in BP in a patient with previously stable HT.

Age < 30 years in non-obese, patients with a negative F/H and no other risk factors.

Malignant or accelerated HT (e.g., patients with severe hypertension and signs of end-organ damage such as retinal hemorrhages or papilledema, heart failure, neurologic disturbance, or acute kidney injury).

Proven age of onset before puberty

Evaluation of secondary hypertension: Not cost effective for a complete evaluation for secondary HT in every pt. Important to be aware of the clinical clues that suggest secondary HTN

CLINICAL CLUES FOR RENOVASCULAR HYPERTENSION 

Onset of severe HTN(blood pressure ≥180 mmHg systolic and/or 120 mmHg diastolic) after the age of 55 years

Unexplained deterioration of kidney function during antihypertensive therapy

Severe hypertension in patients with diffuse atherosclerosis

Severe hypertension in a patient with an unexplained atrophic kidney

A systolic-diastolic abdominal bruit that lateralizes to one side.

Evaluation of secondary hypertension:

Identifiable Hypertension and Screening TestsCondition Screening Test

Chronic kidney disease Estimated glomerular filtration rate

Coarctation of the aorta Computed tomography angiography

Cushing syndrome; other states of glucocorticoid excess

Dexamethasone suppression test

Drug-induced/drug-related HTN Drug screening

Pheochromocytoma 24-hour urinary metanephrine and normetanephrine

Primary aldosteronism, other states of mineralocorticoid excess

24-hour urinary aldosterone level, specific mineralocorticoid tests

Renovascular hypertension Doppler flow U/S, MR Angiography, computed tomography angiography

Sleep apnea Sleep study with oxygen saturation (ESS)

Thyroid/parathyroid disease Thyroid stimulating hormone level, serum parathyroid hormone level

Less aggressive targeting of blood pressures and treatment-initiation thresholds for elderly patients and for those younger than age 60 years with diabetes and kidney disease

Initial therapy in most patients (ACE) inhibitors, angiotensin receptor blockers [ARBs], calcium channel blockers, or diuretics are recommended).

Initiate therapy in 60 years with BP levels at 150/90 mm Hg or greater

In younger than 60 years as well as those older than 18 years with either chronic kidney disease (CKD) or diabetes, the BP treatment initiation and goals should be 140/90 mm Hg.

In nonblack hypertensive patients, begin treatment with either a thiazide-type diuretic, CCB, ACE inhibitor, or ARB

Treatment Guidelines:

In hypertensive black patients, initiate therapy with a thiazide-type diuretic or CCB

Regardless of race or DM, in 18 years or older with CKD, therapy should consist of an ACE inhibitor or ARB

Do not use an ACE inhibitor together with an ARB in the same patient

If goal is not achieved within 1/12, increase the dose or add an agent from another of the recommended drug

If 2-drug therapy is unsuccessful, add a third agent from the recommended drug classes.

If goal BP cannot be reached with 3/12 use agents from other drug classes and/or refer the patients to a hypertension specialist

Treatment Guidelines:

Treatment should be started in all patients (any age) with stage 2 hypertension. Treat isolated systolic hypertension in the same way Initial Drug Choices

If the patient is young (≤55 years) and non-black, start with:• (A) angiotensin-converting enzyme (ACE) inhibitor or low-cost angiotensin-II receptor antagonist (AIIRA).• A beta-blocker may be appropriate in younger adults if an ACE is not tolerated, in women who may become pregnant or if there is evidence of increased sympathetic drive.

If the patient is aged >55 years or a black person of African or Caribbean family origin, use:• (C) calcium-channel blocker (CCB).

Stage 2 Drug Choices

• (A+C) ACE inhibitor or AIIRA with CCB.• Use an ACE/AIIRA and a thiazide-like diuretic (D) if CCB is not tolerated (or if there is any evidence of heart failure).• If initially started on a beta-blocker, add a CCB rather than a thiazide-like diuretic second-line (reduce diabetic risk).

• Consider an AIIRA rather than an ACE with a CCB in black (African or Caribbean) patients

Treatment should be started in all patients (any age) with stage 2 hypertension. Treat isolated systolic hypertension in the same way Stage 3 Drug Choices

• (A+C+D) ACE inhibitor or AIIRA and a CCB and a thiazide-like diuretic (chlortalidone or indapamide).

Stage 4 Drug Choices

• (A+C+D) ACE inhibitor or AIIRA and a CCB and a thiazide-like diuretic plus a further diuretic (higher-dose thiazide-like diuretic or spironolactone, depending on potassium). If the higher-dose diuretic is not tolerated, consider an alpha- or beta-blocker, or seek expert advice.

The combination of an ACE inhibitor with an AIIRA is not recommended for the treatment of hypertension

Treatment targets People aged <80 years: clinic <140/90 mm Hg, ABPM/HBPM <135/85 mm Hg.People aged ≥80 years: clinic <150/90 mm Hg, ABPM/HBPM <145/85 mm Hg.

Urgent treatment needed: Accelerated

hypertension, severe hypertension (>220/>120 mm Hg) or impending complications (e.g. (TIA), (LV) failure).

Possible underlying cause: low K+, Na+ elevated (possible Conn's syndrome); elevated creatinine, proteinuria or haematuria; rapidly worsening or resistant hypertension (i.e. needs >3 drugs); young age: patient aged <20 years, or <30 years needing treatment.

Therapeutic problems: Multiple drug

intolerance or contra-indications, persistent noncompliance or treatment refusal (the reluctant hypertensive).

Special situations: hypertension in pregnancy, unusual BP variability.

Indications for specialist referral