Hypertension

Dr. Gerrard Uy

Hypertension

• doubles the risk of cardiovascular diseases• present in all populations except for a small

number of individuals living in primitive, culturally isolated societies

• accounts for 6% of deaths worldwide

Risk Factors

• Obesity and weight gain• High dietary NaCl intake• Low dietary Ca and Potassium• Alcohol consumption• Pyshosocial stress• Low levels of physical activity• genetic

Mechanism of hypertension

• Cardiac output and peripheral resistance are the two determinants of arterial pressure

Mechanism

• Intravascular Volume• Autonomic Nervous System• Renin-Angiotensin Aldosterone• Vascular Mechanisms

Vascular Volume

• Vascular volume is a primary determinant of arterial pressure over the long term

• alterations in total extracellular fluid volume are associated with proportional changes of blood volume

• Sodium is predominantly an extracellular ion

Autonomic Nervous System

• Adrenergic reflexes:– norepinephrine, epinephrine, and dopamine

• Baroreceptor reflexes:– Carotid sinus, aortic arch

Renin-Angiotensin Aldosterone

Pathologic consequences

• Heart– most common cause of death in hypertensive patients

• Brain– Hypertension is an important risk factor for brain

infarction and hemorrhage• Kidney– Primary renal disease is the most common etiology of

secondary hypertension• Peripheral Arteries– blood vessels may be a target organ for

atherosclerotic disease secondary to long-standing elevated blood pressure

Defining hypertension

• based on the average of two or more seated blood pressure readings during each of two or more outpatient visits

Blood Pressure Classification Systolic, mmHg Diastolic, mmHg

Normal <120 and <80

Prehypertension 120–139 or 80–89

Stage 1 hypertension 140–159 or 90–99

Stage 2 hypertension 160 or 100

Isolated systolic hypertension 140 and <90

• Home blood pressure and average 24-h ambulatory blood pressure measurements are generally lower than clinic blood pressures

• Increasing evidence suggests that home blood pressures, including 24-h blood pressure recordings, more reliably predict target organ damage than office blood pressures

• Blood pressure tends to be higher in the early morning hours, soon after waking, than at other times of day

• Myocardial infarction and stroke are more frequent in the early morning hours

• white coat hypertension : 15 – 20 % with stage 1 hypertension have

Clinical disorders

• Essential hypertension– 80 – 95%– primary or idiopathic hypertension– No identifiable cause

• Secondary hypertension– 5 – 20 %– a specific underlying disorder causing the

elevation of blood pressure can be identified

Essential Hypertension

• likely to be the consequence of an interaction between environmental and genetic factors

• increases with age

Secondary Hypertension

• Renal (Parenchymal disease, tumors)• Renovascular (Arteriosclerotic)• Adrenal (Primary aldosteronism, Cushing's

syndrome)• Aortic coarctation• Obstructive sleep apnea• Preeclampsia/ Eclampsia

Secondary Hypertension

• Neurogenic (psychogenic, polyneuritis)• Endocrine (hypo/hyperthyroidism)• Medications (estrogen, decongestant)

Approach to patient

• HISTORY– Duration– Associated symptoms (headache, etc)• Occipital, early morning

– Previous meds– Family history– Diet and social history– Risk factors: weight change, DM, smoking– Evidence of secondary causes

Approach to patient

• Measurement of BP– Before taking the blood pressure measurement,

the individual should be seated quietly for 5 min in a private, quiet setting with a comfortable room temperature

– center of the cuff should be at heart level– width of the bladder cuff should equal at least

40% of the arm circumference– length of the cuff bladder should encircle at least

80% of the arm circumference

Methods in determining BP

• Auscultatory method– Stethoscope over antecubital area– BP cuff inflated over upper arm– Korotkoff sounds– Mechanism:• When cuff pressure is higher than systolic P, brachial

artery remains occluded• As cuff pressure is reduced, blood jets through the

artery, hearing tapping sounds from antecubital artery• When cuff pressure is equal diastolic pressure, blood

no longer jets through squeezed artery, tapping stops

Approach to patient

• PE– Body habitus, weight, height– Arterial pulse, upper and lower extremities– Heart rate– Neck palpated– Eye exam– Abdominal palpation– Neurologic exam

Treatment

• LIFESTYLE intervention

Weight reduction Attain and maintain BMI < 25 kg/m2

Dietary salt reduction < 6 g NaCl/d

Adapt DASH-type dietary plan Diet rich in fruits, vegetables, and low-fat dairy products with reduced content of saturated and total fat

Moderation of alcohol consumption For those who drink alcohol, consume 2 drinks/day in men and 1 drink/day in women

Physical activity Regular aerobic activity, e.g., brisk walking for 30 min/d

• Blood pressure may be lowered by 30 min of moderately intense physical activity, such as brisk walking, 6–7 days a week, or by more intense, less frequent workouts

• Alcohol use in persons consuming three or more drinks per day

• DASH (Dietary Approaches to Stop Hypertension) - 8-week period a diet

Pharmacologic therapy

• Drug therapy is recommended for individuals with blood pressures 140/90 mmHg

• Examples of drugs:– Diuretics : Thiazides: HCTZ– Beta blockers: Metoprolol– ACE Inhibitors: Captopril– Angiotensin II Antagonists: Losartan– Calcium blockers: Verapamil