D.BASEM ELSAID ENANYLECTURER OF CARDIOLOGY

AINSHAMS UNIVERSITY

Hypertension: Diagnosis

--Treatment of hypertension is the most common reason for office visits to physicians in the United States.-- Number of patients with hypertension is likely to grow as the population ages.-- The rising incidence of obesity will also increase the number of hypertensive individuals.-- Control of the disease is far from adequate:Poor access to health care and medicationsLack of adherence with long-term therapy for a condition that is usually asymptomatic

DEFINITIONS

--The seventh report of the Joint National Committee (JNC 7):Based upon the average of two or more properly measured readings at each of two or more visits after an initial screen:

*Normal blood pressure: systolic <120 mmHg and diastolic <80 mmHg*Prehypertension: systolic 120-139 mmHg or diastolic 80-89 mmHg*Hypertension:Stage 1: systolic 140-159 mmHg or diastolic 90-99 mmHgStage 2: systolic ≥160 or diastolic ≥100 mmHg*Isolated systolic hypertension ≥140/<90 mmHg*Isolated diastolic hypertension <140/≥90 mmHg.

European guidelines 2007

Definitions based upon ambulatory and home readings

*A 24-hour average above 135/85 mmHg*Daytime (awake) average above 140/90 mmHg*Nighttime (asleep) average above 125/75 mmHg-- Home readings correlate more closely with the results of daytime ambulatory measurements than with blood pressure taken in the physician's office. Thus, the definition of hypertension based upon an average of multiple home readings is the same as for daytime ambulatory blood pressure.=The current ACC/AHA guidelines for exercise stress testing suggest a hypertensive response to exercise is one in which systolic blood pressure rises to more than 250 mm Hg or diastolic blood pressure rises to more than 115 mm Hg.

ESSENTIAL (PRIMARY) HYPERTENSION

--Pathogenesis:Poorly understood. A variety of factors have been implicated, including:

*Increased sympathetic neural activity, with enhanced beta-adrenergic responsiveness.*Increased angiotensin II activity and mineralocorticoid excess. *Hypertension is about twice as common in subjects who have one or two hypertensive parents and multiple epidemiologic studies suggest that genetic factors account for approximately 30 % of the variation in blood pressure in various populations.*Reduced adult nephron mass may predispose to hypertension, which may be related to genetic factors, intrauterine developmental disturbance (eg, hypoxia, drugs, nutritional deficiency), and post-natal environment (eg, malnutrition, infections).

Risk factors

--A variety of risk factors have been associated with essential hypertension:

*Hypertension tends to be both more common and more severe in blacks.*Excess sodium intake increases the risk for hypertension, and sodium restriction lowers blood pressure. *Excess alcohol intake is associated with the development of hypertension. *Obesity and weight gain are major risk factors for hypertension and are also determinants of the rise in blood pressure that is commonly observed with aging. *Physical inactivity increases the risk for hypertension, and exercise is an effective means of lowering blood pressure.*Dyslipidemia, independent of obesity is associated with hypertension.*Data are conflicting as to whether a high intake of fructose from sugar-sweetened beverages is or is not associated with an increased risk of developing hypertension.*Hypertension may be more common among those with certain personality traits, such as hostile attitudes and time urgency/impatience.*Vitamin D deficiency is associated with an increased risk of hypertension

SECONDARY OR IDENTIFIABLE HYPERTENSION

*Primary renal disease:Both acute and chronic kidney disease, particularly with glomerular or vascular disorders. Polycystic kidney (Bilateral abdominal palpable masses commonly are due to polycystic kidney disease. Typically the history reveals the presence of hypertension with renal failure in other family members), (transient episode of periorbital swelling and dark-colored urine that went untreated may point to a chronic glomerulonephritis), (Multiple episodes of cystitis or urinary infection left untreated or with incomplete treatment will lead to and suggest chronic pyelonephritis)*Oral contraceptives:Oral contraceptives often raise the blood pressure within the normal range but can also induce overt hypertension.*Drug-induced:Chronic nonsteroidal antiinflammatory agents and many antidepressants can induce hypertension. Chronic alcohol intake and alcohol abuse can also raise blood pressure.*Pheochromocytoma:About one-half of patients with pheochromocytoma have paroxysmal hypertension, most of the rest have what appears to be primary hypertension.The preferred treatment is laparoscopic adrenalectomyThe best screening test is plasma free metanephrines (normetanephrine and metanephrine).*Primary aldosteronism:The presence of primary mineralocorticoid excess, primarily aldosterone, should be suspected in any patient with the triad of hypertension, unexplained hypokalemia, and metabolic alkalosis. However, some patients have a normal plasma potassium concentration. The prevalence of primary aldosteronism should also be considered in patients with resistant hypertension. Aldosterone/renin level >20 (morning level)

*Renovascular disease:Common disorder, occurring primarily in patients with generalized atherosclerosis.=Onset at young age (<35 years) in female patient Renal artery medial fibromuscular dysplasia=Onset at a late age (>55 years), especially in a patient with atherosclerosis,Exaggerated drop in blood pressure and/or kidney function with initiation of ACEI,Abdominal bruit Renal artery stenosis*Cushing's syndrome:Hypertension is a major cause of morbidity and death in patients with Cushing's syndrome=excess cortisol (pituitary tumor=Cushing’s disease or adrenal tumor or ectopic ACTH). HTN, DM, central obesity, osteoporosis, hypokalemia, abdominal stria*Other endocrine disorders:Hypothyroidism, hyperthyroidism, and hyperparathyroidism may also induce hypertension.*Obstructive sleep apnea:Independent risk factor for systemic hypertension.*Coarctation of the aorta:One of the major causes of secondary hypertension in young children*Hyperparathyroidism: Renal calculi, elevated calcium level

-Many patients with pheochromocytoma have a normal baseline blood pressure,with high blood pressure values only on occasion. Postural hypotension is a classical feature.High serum catecholamine levels explain the sweating and palpitations and the low fever, elevationof serum glucose, and leukocytosis. Gentle palpation of the abdomen during physical examinationmay sometimes trigger a crisis. Because of the general and metabolic manifestations of the disease,it may mimic a large variety of conditions (e.g., vasculitis, diabetes), and a high level of suspicion isalways necessary.Some patients present with a high blood pressure that is constant rather than paroxysmal. A ruleof 10 may be applied: 10% of all cases are familial, 10% are bilateral, 10% are due to a malignantadrenal tumor, 10% recur, 10% are extra-adrenal, 10% occur in children, 10% are associated witha multiple endocrine neoplasia (MEN) syndrome, and 10% present with a stroke as the inauguralsymptom.Diagnosis of a pheochromocytoma is rewarding because this very sick patient who is prone tolife-threatening complications can be virtually cured. The current recommendation for biochemicaldiagnosis of pheochromocytoma is urine testing for metanephrines and fractionated catecholamines.These tests only certify the presence of a catecholamine-secreting tumor; therefore, the next step isto localize it (90% are in the adrenal medulla; the other 10% are scattered where chromaffin tissue isfound). The preferred treatment is laparoscopic adrenalectomy.

Up to 5% of all hypertension cases are secondary, meaning that a specific cause can be identified.Most of these causes are treatable (e.g., surgery for an adrenal tumor, stenting of a renal arterystenosis, or correction of an aortic coarctation).-Given the low prevalence of secondary hypertension,routine screening for secondary hypertension is not usually recommended

COMPLICATIONS

*Hypertension is quantitatively the major risk factor for premature cardiovascular disease, being more common than cigarette smoking, dyslipidemia, or diabetes, the other major risk factors. In older patients, systolic pressure and pulse pressure are more powerful determinants of risk than diastolic pressure.*The risk of heart failure increases with the degree of blood pressure elevation.*Left ventricular hypertrophy is a common finding in patients with hypertension, and is associated with an enhanced incidence of heart failure, ventricular arrhythmias, death following myocardial infarction, and sudden cardiac death.*Hypertension is the most common and most important risk factor for ischemic stroke, the incidence of which can be markedly reduced by effective antihypertensive therapy.*Hypertension is the most important risk factor for the development of intracerebral hemorrhage.*Hypertension is a risk factor for chronic kidney disease and end-stage renal disease. It can both directly cause kidney disease, called hypertensive nephrosclerosis, and accelerate the progression of a variety of underlying renal diseases.*Marked elevations in blood pressure can cause an acute, life-threatening emergency

Screening

--The 2007 United States Preventive Services Task Force (USPSTF) guidelines on screening for high blood pressure recommend screening every two years for persons with systolic and diastolic pressures below 120 mmHg and 80 mmHg, respectively (normal BP in JNC 7), and yearly for persons with a systolic pressure of 120 to 139 mmHg or a diastolic pressure of 80 to 89 mmHg (prehypertension in JNC 7).

Measurement

--In the absence of end-organ damage, the diagnosis of mild hypertension should not be made until the blood pressure has been measured on at least three to six visits, spaced over a period of weeks to months. -- Sequential studies have shown that the blood pressure drops by an average of 10 to 15 mmHg between visits one and three, thus, many patients considered to be hypertensive at the initial visit are in fact normotensive.-- The presence of postural hypotension, defined as a 20 mmHg or greater fall in systolic pressure upon rising from supine to an unassisted upright position, should be pursued in patients over age 65, those experiencing dizziness or weakness upon standing, or those with diabetes.

White coat hypertension and ambulatory monitoring

--Approximately 20 to 25% of patients with stage 1 office hypertension have "white-coat" or isolated office hypertension in that their blood pressure is repeatedly normal when measured at home, at work, or by ambulatory blood pressure monitoring.--More common in the elderly, but is infrequent (less than 5 %) in patients with office diastolic pressures ≥105 mmHg.--Ambulatory blood pressure monitoring (ABPM), which records the blood pressure at preset intervals (usually every 15 to 20 minutes during the day and every 30 to 60 minutes during sleep), can be used to confirm or exclude the presence of white coat hypertension in patients with persistent office hypertension but normal blood pressure readings out of the office.--Masked hypertension: 24-hour monitoring of larger populations has revealed a significant number of patients with elevated out-of-office readings despite normal office readings.

Indications for ABPM:--Suspected white coat hypertension--Suspected episodic hypertension (eg, pheochromocytoma)--Hypertension resistant to increasing medication--Hypotensive symptoms while taking antihypertensive medications--Autonomic dysfunction--Non dippers=Failure of the BP to fall by at least 10 % during sleep {risk factor for the development of left ventricular hypertrophy (LVH), heart failure and other cardiovascular complications, associated with microalbuminuria and faster progression of nephropathy in patients with diabetes mellitus}.

EVALUATION

--To determine the extent of target organ damage.--To assess the patient's overall cardiovascular risk status.--To rule out identifiable and often curable causes of hypertension.

History, examination

--For: Precipitating or aggravating factors (including prescription medications, non-prescription nonsteroidal antiinflammatory agents, and alcohol consumption)The natural course of the blood pressureThe extent of target organ damagePresence of other risk factors for cardiovascular disease

Laboratory testing

--The only tests that should be routinely performed include:*Hematocrit, urinalysis, routine blood chemistries (glucose, creatinine, electrolytes), and estimated glomerular filtration rate*Lipid profile (total and HDL-cholesterol, triglycerides)*Electrocardiogram--Additional tests may be indicated in certain settings:*Echocardiography is indicated to detect possible end-organ damage (LVH).

*Microalbuminuria{persistent albumin excretion between 30 and 300 mg/day}:-Appears to be a signal that the vasculature, particularly the endothelium, is not functioning normally.-Relation to renal disease, important risk factor for cardiovascular disease and early cardiovascular mortality.- K/DOQI guidelines {Kidney Disease Outcome Quality Initiative }suggest that microalbuminuria alone that persists for more than three months falls within the definition of chronic kidney disease. -Measurement of the urine albumin-to-creatinine ratio in an untimed urinary sample is the preferred screening strategyit does not require early morning or timed collections, it gives a quantitative result that correlates with the 24-hour urine values over a wide range of protein excretion, it is simple to perform and inexpensive, and repeat values can be easily obtained to ascertain that microalbuminuria, if present, is persistent. -ACE inhibitor or angiotensin II receptor blocker (ARB) greater ability of these drugs to reduce albuminuria compared to other antihypertensive drugs.

*Testing for renovascular hypertension:--Indicated only in patients in whom there are suggestive clinical clues and only if a corrective procedure will be recommended if significant renal artery stenosis is detected.--At present, there is no sufficiently accurate, noninvasive radiologic or serologic screening test that, if negative, will completely exclude the presence of renal artery stenosis.--Medical therapy for control of hypertension is indicated in all patients with unilateral renal artery stenosis.--Revascularization, usually by percutaneous angioplasty with stenting, is reasonable in patients with a hemodynamically significant lesion who have resistant hypertension, malignant hypertension, an inability to tolerate antihypertensive medications, or recurrent episodes of flash pulmonary edema.--Surgery is primarily warranted for correction of complex lesions.

*Serum Uric Acid:Hyperuricemia has been found to be a precursor and possible pathogenetic factor for hypertension. It is not known whether the presence of hyperuricemia or its treatment will influence the management of hypertension.*Ambulatory blood pressure monitoring *Plasma renin activity:Although the PRA may provide prognostic information, the test is usually performed only in patients with possible low-renin forms of hypertension, such as primary mineralocorticoid excess. The PRA may provide guidance in the evaluation of resistant hypertension.

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