91992002 management-of-hypertension-in-clinical-dentistry

Management of Hypertension in Clinical Dentistry

By:-mohammed alsamraee

DEFINITION

Hypertension is a persistently raised blood pressure resulting from increased peripheral arteriolar resistance. This condition is also known as hypertensive cardiovascular disease and hypertensive heart disease (HHD).

The cause of hypertension is unknown in most cases and the disorder is therefore termed essential hypertension.

Primary hypertension, and idiopathic hypertension are synonymous and interchangeable terms, meaning that no cause other than genetics can be found.

Dental management in hypertensive patients can be complicated, since any procedure causing stress can further increase the blood pressure and can precipitate acute complications such as a cardiac arrest or a cerebrovascular accident. Chronic complications of hypertension, especially impaired renal function, can affect dental management.

The diagnosis of hypertension is made at an arbitrary point when the blood pressure at rest exceeds 160 mm Hg systolic pressure or where diastolic pressure exceeds 95 mm Hg (World Health Organization), or where systolic is above 140 mm Hg and diastolic above 90mm Hg (American Heart Association). By these criterion some 10 per cent or more of the population in the U.S. are hypertensive. A more recent consensus report of the Fifth Joint National Committee (JNC-V) has set arbitrary limits for resting and seated arm blood pressure, which defines hypertension to be systolic pressure above 140 mm Hg, and diastolic pressure above 90 mm Hg. This classification also includes a systolic component, unlike the previous guideline by the same committee (JNC-IV, 1988) which defined hypertension as mean diastolic pressure of 90 mm Hg or greater, with no regard to a systolic component. The newer 1993 guideline has set 4 stages of hypertension which emphasize the seriousness and severity of the condition.

A rise in diastolic blood pressure is much more significant than a rise in systolic pressure, since the higher diastolic pressure translates to a prolonged greater baseline arterial pressure, and therefore may precipitate arteriosclerosis and other end-organ pathology.

CLASSIFICATION OF BLOOD PRESSURE IN ADULTS 18 OR OLDER

SYSTOLIC DIASTOLIC

Category Pressure (mm HG) Pressure (mm Hg)

Normal BP < 130 < 85

High Normal BP 130-139 85-89

Hypertension

Stage I 140-159 90-99

Stage II 160-179 100-109

Stage III 180-209 110-119

Stage IV > 210 > 120

From the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure. The fifth report of the Joint National

Committee on Detection, Evaluation, and Treatment of High Blood Pressure. Arch Intern Med 153:154-83, 1993

The blood pressure is easily measured with a sphygmomanometer. Since the blood pressure increases with anxiety, measurements should be made with the patient relaxed and fully at rest. Generally, the first three readings tend to be highest. But in an office practice, taking two values and averaging is recommended.

TABLE 3: TECHNIQUE FOR RECORDING THE BLOOD PRESSURE

1. Seat and relax the patient. 2. Place sphygmomanometer cuff on right upper arm with about 3cm of skin

visible at the antecubital fossa. (Proper cuff size should be chosen; too small cuff on an obese or large, muscular arm falsely elevates the reading; too large cuff on a small arm gives a falsely low reading.)

3. Palpate radial pulse. 4. Inflate cuff to about 200 to 250 mmHg, or until the radial pulse is no longer

palpable. 5. Deflate cuff slowly while listening with stethoscope over the brachial artery

over skin on inside of arm below cuff. 6. Record the systolic pressure as the pressure when the first tapping sound

(Korotkoff sound) appear. 7. Deflate cuff further until the tapping sounds become muffled (diastolic

pressure). 8. Repeat. Record blood pressure as systolic/diastolic pressure.

PATHOGENESIS AND RISK ASSESSMENT

Essential hypertension becomes more common as age advances and genetic influences, obesity, excessive salt intake and a variety of other factors are contributory. Hypertension is secondary to defined diseases, particularly renal or endocrine disorders, in about 10-20 percent of hypertensive cases and occasionally can be secondary to the use of oral contraceptives.

Acute emotion, particularly anger and anxiety, can cause transient rises in blood pressure by release of catecholamines (epinephrine and norepinephrine) and about 40 percent of hypertensive patients have raised levels of circulating catecholamines (epinephrine and norepinephrine) and may therefore have abnormal sympathetic activity.

When the patient has a history of hypertension there is the possibility of both congestive heart failure or angina pectoris. It is natural to think of stroke first when confronted with a history of hypertension, and it is true that hypertension, diabetes, and cerebral hemorrhage are commonly linked, but the fact is that 65 percent of hypertensives die of heart disease, whereas 20 percent demonstrate predominantly cerebral complications, except in hypertensive African American persons. African Americans tend to develop hypertension earlier in life. It is frequently more severe, and resulting in a higher mortality at a younger age, more commonly from stroke than from coronary artery disease. Since hypertension is one of several predisposing factors for premature coronary disease, it is important to look for other factors that may add to that risk, especially hyperlipidemia and cigarette smoking. Diabetes and physical inactivity likewise are important.

MANAGEMENT IN CLINICAL DENTAL SITUATIONS

Dentists have a unique opportunity to detect cases of hypertension since patient visits at routine intervals are encouraged. It is a professional responsibility of a dental clinician to inform the patient of their hypertensive state and to offer medical advice, including appropriate referrals.

There are no recognized oral manifestations of hypertension but antihypertensive drugs can often cause side-effects, such as:

xerostomia, gingival overgrowth, salivary gland swelling or pain, lichenoid drug reactions, erythema multiforme, taste sense alteration, and paresthesia.

Dental clinician must focus on the actions, interactions and adverse effects of the antihypertensive medications, as well as the overall management of blood pressure of the patient in the dental chair. (see Medications)

The appropriate modifications for differing stages of hypertension is outlined in the algorithm presented below. (see ALGORITHM) There are, however, several areas of general dental management to be considered in the hypertensive patients.

1. ANESTHESIA

A. Local Anesthesia

Dental patients with hypertension are best treated under local anesthesia being sure that the anesthesia is complete so that no anxiety induced elevation of blood pressure occurs. The use of vasoconstrictors such as epinephrine in local anesthetic agents is known to have negligible influences on blood pressure in hypertensive patients, according to numerous clinical studies. Data in regard to epinephrine-containing local anesthetics has consistently shown that blood pressure and heart rate are minimally affected by the typically low dose and short duration of the drug use in dentistry, both in healthy and those with existing cardiovascular conditions. Nonetheless, the use of epinephrine-containing anesthetics in patients with uncontrolled hypertension, and elective dental procedures are contraindicated. According to Muzyka& Glick (JADA 1997),

"the benefits of the small doses of epinephrine used in dentistry, when administered properly,far outweigh the cardiovascular disadvantages"

The use of aspirating syringes in local anesthetics is imperative to avoid intravenous, intrarterial, intraligamentary and intrabony injections, which could potentially precipitate further anxiety and thus rise in pressure and possible arrhythmias.

B. General Anesthesia

All antihypertensive drugs are potentiated by general anesthetic agents, especially barbiturates. General anesthesia tends to cause vasodilation. A severely reduced blood supply to vital organs can be dangerous in healthy individuals, but in the hypertensive person with vascular disease there is greater risk as the tissues have become adapted to a raised blood pressure which is needed to overcome the resistance of the vessels and maintain adequate perfusion. A fall in blood pressure below the critical level needed for adequate perfusion of vital organs such as the kidneys, can therefore be fatal. Hypokalemia as a result of diuretics may be associated with arrhythmias. Some inhalant anesthetics (halothane, enfluane, and

isoflurane) are similar in action to calcium slow channel antagonists and so reduce blood pressure significantly.

2. ANXIETY CONTROL

The anxiety and stress associated with dental treatment typically causes a rise in blood pressure and may precipitate cardiac arrest or a cerebrovascular accident. Preoperative reassurance and oral sedation may help in alleviating anxiety related rise in pressure. Use of sedatives the night before a procedure may also be used.

Relative analgesia technique using nitrous oxide (N2O) can also reduce both systolic and diastolic pressure by up to 10-15mm Hg, after approximately 10 minutes of use, preoperatively. Use of oral sedation or nitrous oxide sedation may reduce blood pressure to acceptable levels, allowing initiation of local anesthesia (with or with vasoconstrictor).

3. TIMING OF DENTAL APPOINTMENTS

The increase of blood pressure in hypertensive patient is associated with the hours surrounding awakening that peaks by midmorning. This fluctuation of blood pressure tends to be less likely in the afternoon. Afternoon appointments are recommended over mornings for this reason.

4. ORTHOSTATIC HYPOTENSION

Orthostatic hypotension may be a problem in patients using antihypertensive agents that reduce sympathetic outflow or peripheral vasodilatory actions, such as centrally acting a-2-adrenergic agonists, post-ganglionic adrenergic inhibitors, a-1-adrenergic antagonists, and diuretics. Management of orthostatic hypotension includes avoiding sudden postural changes, such as return to sitting position from the supine operating position. The patient should also be instructed to stay seated for a short period until such time that adequate cerebral perfusion has occured.

5. OTHER DENTAL CONCERNS

Aspirin is now commonly taken by patients with hypertension to decrease associated coronary or cerebral vascular thrombotic disease, and aspirin may cause bleeding problems. Many patients with hypertension develop systolic heart murmurs, in which case prophylaxis for endocarditis

Algorithm for Management of Hypertensive Dental Patient

* SELECTIVE DENTAL PROCEDURE may include, but not limited to;

dental prophylaxis restorative procedures nonsurgical periodontal therapy nonsurgical endodontic procedures

# EMERGENT NONSTRESSFUL DENTAL PROCEDURE may include, but not limited to dental procedures that may help alleviate pain, infection or masticatory dysfunction. e.g., simple incision and drainage of intraoral fluctuant dental abscess.The medical benefits should outweigh the risk of complications secondary to the hypertensive state, in stage III and IV hypertensive patients.

Modified from:

1. Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure. The fifth report of the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure. Arch Intern Med 153:154-83, 1993

2. Muzyka B.C., and M. Glick. The hypertensive dental patient, JADA 128: 1109-1120, 1997

ORAL MEDICATIONS USED FOR MANAGEMENT OF HYPERTENSION

(common brand names available in the U.S. is shown in bracket)

DiureticsBeta-Adrenergic BlockersCentral Acting InhibitorsPeripheral-Acting Adrenergic InhibitorsNon selective Alpha and Beta Adrenergic BlockersVasodilatorsAngiotensin-Converting Enzyme (ACE) Inhibitors

DIURETICS

TOP

A. Thiazides and related sulfonamides

Mode of action:

increase the excretion of Na+, Cl-, and water by interfering with the transport of sodium ions across the renal tubular epithelium reduce blood pressure by decreasing cardiac output

Representative agent:

hydrochlorothiazide

Side effects:

xerostomia increased thirst orthostatic hypotension polyuria dizziness

fatigue, weakness

B. Loop diuretics (also called High-efficiency diuretics)

Mode of action:

inhibit Na+ and Cl- reabsorption in the descending limbs of the loop of Henle enhance excretion of K+, Mg++, and Ca++. reduce blood pressure by decreasing fluid volume and thereby reducing

cardiac output

Representative agents:

furosemide ethacrynic acid bumetanide

Side effects:

xerostomia increased thirst lichenoid drug reaction neutropenia leukopenia anemia orthostatic hypotension renal failure

C. Potassium-sparing agents

Mode of action:

competitive antagonism of the endogenous mineralocorticoid aldestrone change

pressure levels and reduce blood pressure by reducing total fluid volume


amiloride

spironolactone (Aldactone) triamterene

Side effects:

xerostomia increase thirst gingival bleeding (spironolactone) lichenoid drug reaction

D. Carbonic anhydrase inhibitors

Mode of action:

inhibition of the enzyme carbonic anhydrase in the proximal and distal segments of the renal tubule so as to allow diuresis

reduce blood pressure by decreasing fluid volume and thereby reducing cardiac output


acetazolamide dichlorphenamide methazolamide

Side effects:

xerostomia burning mouth, tongue, lips parasthesia metallic taste thirst

BETA-ADRENERGIC BLOCKERS

TOP

Mode of action:

blocks b-1 and b-2 receptors in cardiac effect: by blocking beta-1 receptors, reduces rate of SA node firing

rate, slows the conduction through AV node, and reduces contractile strength and automaticity

in the vascular system, reduce blood pressure by reducing cardiac output and increasing peripheral resistance


Acebutolol atenolol metoprolol nadolol penbutolol pindolol propranolol timolol

Side effects

orthostatic hypotension xerostomia sore throat nasal stuffiness asthma drowsiness depression fluid retention

CENTRAL-ACTING ADNERNERGIC INHIBITORS

TOP

Mode of action:

direct effect on alpha 2-adrenoceptor (sympathetic vasomotor center in CNS), which reduces impulses in sympathetic nervous system

reduces blood pressure by decreasing peripheral resistance and by decreasing plasma renin levels


clonidine (Catapres) methldopa (Aldomet) guanabenz guanfacine

Side effects:

xerostomia taste changes salivary pain or swelling palpitation ECG abnormalities insomnia anxiety drowsiness

PERIPHERAL-ACTING ADRENERGIC INHIBITORS

TOP

Mode of action:

inhibits the active uptake of catecholamines into storage vesicles of the nerve terminal

decrease blood pressure by decreasing sympathetic tone, and by decreasing peripheral vascular resistance


guanadrel guanethidine Rauwolfia alkaloids (e.g. reserpine)

Side effects:

xerostomia bleeding thrombocytopenia purpura orthostatic hypotension drowsiness, fatigue, weakness

Mode of action:

decrease total vascular resistance by vasodilation of arterioles and capacitance veins, by selective blocking of alpha 1-receptors on vascular smooth muscle


selective alpha 1-adrenergic blockers o prazosin (Minipress) o terazosin (Hytrin)

Side effects:

xerostomia orthostatic hypertension, postural dizziness nausea, Gl upset drowsiness, fatigue, weakness anxiety, depression

NONSELECTIVE ALPHA- AND BETA- ADRENERGIC BLOCKERS

TOP

Mode of action:

competitive blocking of both a- and b- adrenergic receptors (greater affinity for b- receptors) on vascular smooth muscle

decrease blood pressure by decreasing peripheral vascular resistance


labetalol (Normodyne, Trandate)

Side effects:

xerostomia taste changes orthostatic hypotension

nausea, Gl upset nervousness anxiety, depression parasthesia bronchospasm

VASODILATORS

TOP

Mode of action:

direct relaxation (vasodilation) of arteriolar smooth muscle decrease blood pressure by decreasing peripheral vascular resistance


hydralazine (Apresoline) minoxidil (Loniten)

Side effects:

nasal congestion lupus-like syndromes leukopenia

ANGIOTENSIN-CONVERTING ENZYME (ACE) INHIBITORS

TOP

Mode of action:

inhibits ACE preventing conversion of angiotension I to angiotensin II, resulting in dilation of arteriole, venous vessels

decrease blood pressure by removing the vasoconstricting effect of ACE and thereby decreasing peripheral vascular resistance


captopril (Capoten)

enalapril (Vasotec) lisinopril (Zestril, Prinivil)

Side effects:

xerostomia loss of taste angiodema glossitis oral ulceration (Stevens-Johnson syndrome - captopril, enapril) lichenoid drug reaction renal insufficiency

Slow Channel Calcium-Entry Blocking Agents

Mode of action:

direct relaxation (vasodilation) of coronary and peripheral arteriolar smooth muscles by blocking Ca++ influx


verapamil (Calan, Isoptin) dilitiazen nifedipine (Adalat, Procadia) nitrendipine

Side effects:

gingival hyperplasia xerostomia orthostatic hypotension light-headedness, nausea edema flushing, skin reactions congestive heart failure

REFERENCES

1. Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure. The fifth report of the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure. Arch Intern Med 153:154-83, 1993

2. Muzyka B.C., and M. Glick. The hypertensive dental patient, JADA 128:1109-1120, 1997

3. Rose L., and D. Kaye. Internal Medicine for Dentistry, 2nd ed. C.V. Wesby Co., St. Louis, 1990.

4. Niedle E.N., and J.A. Yagiela. Pharmacology and Therapeutics for Dentistry, (3rd Ed.) Mosby, St. Louis. 1989

5. Gage T.W., and F.A. Pickett. Dental Drug Reference. Mosby, St. Louise. 1996

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