Diagnostic evaluation of HTN

Diagnostic evaluation of hypertensionHany A. AbdelWahab

(Assistant lecturer of cardiology)Zagazig University

October, 2011

ESC and ESH Guidelines, 2007. European Heart Journal (2007) 28, 1462–1536

Aim of the diagnostic procedures

1) Establishing blood pressure levels.

2) Identifying secondary causes of hypertension.

3) Evaluating the overall cardiovascular risk by

searching for other risk factors, target organ

damage and concomitant diseases.


The diagnostic procedures comprise:

1) Repeated blood pressure measurements.

2) Medical history.

3) Physical examination.

4) Investigations.

BLOOD PRESSURE MEASUREMENTS


• Blood pressure is characterized by large

spontaneous variations therefore the diagnosis

of hypertension should be based on at least 2

blood pressure measurements per visit and at

least 2 to 3 visits, although in severe cases the

diagnosis can be based on measurements taken

at a single visit.


Office or clinic BP measurement

• Allow the patients to sit for several minutes in a quiet room before beginning BP measurements.

• Take at least two measurements spaced by 1– 2 minutes, and additional measurements if the first two are quite different.


• Use a standard bladder size (12–13 cm long and 35 cm wide) but have a larger and a smaller bladder available for fat and thin arms, respectively. Use the smaller bladder in children.


• Have the cuff at the heart level, whatever the position of the patient.


• Measure BP in both arms at the first visit to detect possible differences due to PVD. In this instance, take the higher value as the reference one.

• Measure BP 1 and 5 min after assumption of the standing position if postural hypotension is suspected like in elderly & diabetic patients.

• Measure heart rate by pulse palpation (at least 30 sec) after the second measurement in the sitting position.


Ambulatory BP measurement


• Many studies have also shown that ambulatory blood pressure:

1) Correlates with hypertension-related organ damage and its changes by treatment more closely than does office blood pressure.

2) It can predict cardiovascular risk greater than office blood pressure values in populations as well as in untreated and treated hypertensives.

3) Measures the extent of blood pressure reduction by treatment more accurately than clinic blood pressure.


• It obtains information on both daytime and nighttime BP profiles, day-night BP difference, morning BP rise and BP variability.

• The prognostic value of nighttime BP has been found to be superior to that of daytime blood pressure.

• Subjects in whom nocturnal decrease in blood pressure is blunted (non dippers) have been reported to have a greater prevalence of organ damage and a less favourable outcome.


• 24-h ambulatory BP monitoring should be considered, in particular, when:

1- Considerable variability of office BP.

2- High office BP is measured in subjects otherwise at low total cardiovascular risk.

3- There is a marked discrepancy between BP values measured in the office and at home.


4- Resistance to drug treatment is suspected.

5- Hypotensive episodes are suspected, particularly in elderly and diabetic patients.

6- Office BP is elevated in pregnant women and preeclampsia is suspected.


Home BP measurement


• Self-measurement of BP at home is of clinical value and its prognostic significance is now demonstrated.

• These measurements should be encouraged in order to:

• Provide more information on the BP lowering effect of treatment at trough.

• Improve patient’s adherence to treatment regimens.

• If there are doubts on technical reliability/ environmental conditions of ambulatory BP data.


• Normal values are different for office,

ambulatory and home

BP measurements.


Blood pressure thresholds (mmHg) for definition ofhypertension with different types of measurement

BP measure type SBP DBP

Office or clinic 140 90

24 – hour 125 – 130 80

Day 130 – 135 85

Night 120 70

Home 130 - 135 85


Isolated office (white coat) hypertension

• If the office blood pressure is persistently elevated (≥140/90 mmHg on at least 3 occasions) while daytime or 24-hour blood pressure, or home blood pressure are within their normal range.

• Isolated office hypertension may be present in about 15% of the general population and that it may account for a noticeable fraction (one third or more) of hypertensive patients.


• There is evidence that in individuals with isolated office hypertension cardiovascular risk is less than in individuals with both raised office and ambulatory blood pressure. However, several, although not all studies, have reported this condition to be associated with a prevalence of organ damage and metabolic abnormalities greater than that of normotensive subjects, which suggests that it may not be a clinically innocent phenomenon.


• This condition is more common when there is

Grade 1 (mild) hypertension in females. older ages.Non smokers. Hypertension of recent onset.Limited number of office BP measurements.


Isolated ambulatory (masked) hypertension

• The reverse phenomenon of ‘white coat hypertension’ has also been described: individuals with normal office BP (<140/90 mmHg) may have elevated ambulatory or home BP values, a condition termed ‘isolated ambulatory hypertension’ or ‘masked hypertension’.


• The prevalence in the population is about the same as that of isolated office hypertension.

• Such individuals have been shown to have greater than normal prevalence of organ damage, with an increased prevalence of metabolic risk factors compared with subjects with a truly normal blood pressure.

MEDICAL HISTORY


Guidelines for Family and Clinical History

1. Duration and previous level of high blood pressure.2. Indications of secondary hypertension:

- Family history of renal disease (polycystic kidney).- Renal disease, urinary tract infection, haematuria, analgesic abuse (parenchymal renal disease).- Drug/substance intake: oral contraceptives, liquorice, carbenoxolone, nasal drops, cocaine, amphetamines, steroids, NSAIDs, erythropoietin, cyclosporine.- Episodes of sweating, headache, anxiety, palpitation (phaeochromocytoma).- Episodes of muscle weakness and tetany (aldosteronism).


3. Risk factors:- Family and personal history of hypertension and cardiovascular disease.- Family and personal history of dyslipidaemia.- Family and personal history of diabetes mellitus.- Smoking.- Dietary habits.- Obesity & amount of physical exercise. - Snoring; sleep apnea ( information also from partner)- Personality.


4. Symptoms of target organ damage:- Brain and eyes: headache, vertigo, impaired vision, TIAs & sensory or motor deficit.- Heart: palpitation, chest pain, shortness of breath &swollen ankles.- Kidney: thirst, polyuria, nocturia & haematuria.- Peripheral arteries: cold extremities & intermittent claudications.

5. Previous antihypertensive therapy:

- Drug(s) used, efficacy and adverse effects.

PHYSICAL EXAMINATION


Physical Examination for Secondary Hypertension, Target organ Damage and Visceral Obesity

Signs suggesting secondary hypertension

• Features of Cushing Syndrome.• Skin stigmata of neurofibromatosis (phaeochromocytoma).• Palpation of enlarged kidneys (polycystic kidney).• Auscultation of abdominal murmurs (renovascular

hypertension).• Auscultation of precordial or chest murmurs & delayed femoral

pulses (aortic coarctation or aortic disease).


Signs of organ damage

• Brain: murmurs over carotid arteries, motor or sensory defects.

• Retina: fundoscopic abnormalities.• Heart: apical impulse, abnormal cardiac rhythms,

ventricular gallop, pulmonary rales & peripheral oedema.

• Peripheral arteries: absence, reduction, or asymmetry of pulses, cold extremities, ischaemic skin lesions.


Evidence of visceral obesity

• Increased waist circumference (standing position) M: >102 cm & W: >88 cm

• Increased body mass index: •body weight (Kg)/ height (m²)•Overweight ≥25 Kg/m² & Obesity ≥30 Kg/m²

INVESTIGATIONS


Laboratory Investigations• Routine tests

• Fasting plasma glucose.

• Fasting lipid profile:• Serum total cholesterol• Serum LDL-cholesterol• Serum HDL-cholesterol• Serum triglycerides

• Serum potassium.

• Serum uric acid.


• Serum creatinine.

• Estimated creatinine clearance (Cockroft-Gault formula) or glomerular filtration rate (MDRD formula).

• Haemoglobin and haematocrit.

• Urine analysis (complemented by microalbuminuria dipstick test and microscopic examination).

• Electrocardiogram.


Recommended tests• Echocardiogram.• Carotid ultrasound.• Quantitative proteinuria (if dipstick test positive).• Ankle-brachial BP index.• Fundoscopy.• Glucose tolerance test (if fasting plasma glucose >102

mg/dL).• Home and 24h ambulatory BP monitoring .• Pulse wave velocity measurement (where available).

Peripheral vascular disease

Morbidity

Disability

Renal disease

CADCHFLVHStroke

Hypertension

National High Blood Pressure Education Program Working Group. Arch Intern Med. 1993;153:186-208.

Searching for subclinical organ damage


Heart

• Electrocardiogram should be part of all routine assessment of subjects with hypertension in order to detect: LVH & patterns of “strain” - Ischaemic & conduction defects and arrhythmias.

• Echocardiography is recommended whenever a more sensitive detection of LVH & diastolic and systolic dysfunction can also be evaluated.

LVH


• The relation between left ventricular mass index and cardiovascular risk is continuous & thresholds of 125 g/m2 for men, and 110 g/m2 for women are widely used for conservative estimates of left ventricular hypertrophy.

• Concentric hypertrophy, eccentric hypertrophy, concentric remodelling all predict an increased incidence of cardiovascular disease, but concentric hypertrophy has consistently been shown to be the condition which most markedly increases the risk.


Blood vessels

• Carotids ultrasound is also recommended whenever

detection of vascular hypertrophy (increased thickness

of common carotid intima-media; IMT > 0.9 mm ) or

asymptomatic atherosclerosis (thickening of carotid

bifurcation and internal carotid arteries, presence of

plaques) can predict the occurrence of stroke and MI.


• Large artery stiffening (an important vascular

alteration leading to isolated systolic hypertension;

ISH in the elderly) can be measured in a relatively

simple way by pulse wave velocity.

• A low ankle- brachial BP index < 0.9 signals

peripheral artery disease.


Kidney• The diagnosis of hypertension- related renal damage

is based on the finding of a reduced renal function or the detection of albuminuria in hypertensive patients.

(A) Routine measurement of: - Serum creatinine. - Glomerular filtration rate (MDRD formula) or creatinine

clearance (Cockroft- Gault formula).- Micro and macro albuminuria (dipstick test).

This allows classification of renal dysfunction and stratification of cardiovascular risk.


Fundoscopy• Examination of eye grounds is recommended in severe

hypertensive patients. This is because the mildest retinal changes (grade 1: arteriolar narrowing; grade 2: arterio venous nipping) appear to be largely non-specific alterations except in young patients.

• In contrast grade 3 (haemorrhages and exudates) and 4 (papilloedema), only present in severe hypertension, are associated with an increased risk of cardiovascular events.

• More sensitive methods for quantitatively assessing retinal vascular changes are being developed.


Brain

• Silent brain infarcts, lacunar infarction, microbleeds

and white matter lesions are not infrequent among

hypertensives and can be detected by MRI or CT

(MRI being generally superior to CT).


Take home message

• Proper and repeated BP measurements are essential for proper diagnosis of hypertension.

• History, physical exam and investigations are essential to search for secondary causes of hypertension, target organ damage, concomitant diseases and estimate the cardiovascular risk.

Thank You

Health & Medicine

Diagnostic evaluation of HTN