Hypertension

Hypertension, the most common cardiovascular disease, affects more than 50 million American adults, many of whom are undiagnosed.³ In 2003, the National Heart, Lung and Blood Institute issued revised guidelines for evaluation and management of hypertension.^4–6 The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC-7) guidelines⁴ simplified the classification of blood pressure (Table 37-1).

Compared with previous classification7,8 schemes that focused on diastolic blood pressure (BP), the JNC-7 guidelines⁴ emphasize the importance of systolic BP greater than 140 mm Hg. Systolic blood pressure greater than 140 mm Hg is considered a greater risk factor for cardiovascular disease than elevated diastolic pressure. JNC-7 also introduced a category known as prehypertension to replace the more innocuous terms “high normal” and “borderline” hypertension. People with systolic BP between 120 and 139 mm Hg or diastolic BP between 80 and 89 mm Hg are classified as “prehypertensive.” Hypertension is now classified into only two categories versus three under past classification schemes for simplicity and because treatment for categories 2 and 3 was essentially the same. Stage 1 hypertension is defined by systolic pressure of 140 to 159 mm Hg or diastolic pressure of 90 to 99 mm Hg. Stage 2 hypertension is defined by a systolic pressure greater than 160 mm Hg or diastolic pressure greater than 100 mm Hg.

Hypertension is not diagnosed on a single elevated BP recording. Rather, classification is usually based on the average value of two or more BP readings taken at two or more appointments. The higher value of either the systolic or diastolic pressure determines the patient’s classification. Patients with hypertension enter the dental practice every day and are particularly common among the older population seen in most periodontal practices. Evidence from the Framingham Heart Study revealed that people with normal BP at age 55 still have a 90% risk of becoming hypertensive later in life.⁹

Hypertension is divided into primary and secondary types. Primary (essential) hypertension occurs when no underlying pathologic abnormality can be found to explain the disease. Approximately 95% of all hypertensive patients have primary hypertension. The remaining 5% have secondary hypertension, in which an underlying etiology can be found and often treated. Examples of the conditions responsible for secondary hypertension are renal disease, endocrinologic changes, and neurogenic disorders.

In early hypertension, the patient may be asymptomatic. If not identified and diagnosed, hypertension may persist and increase in severity, leading eventually to coronary artery disease, angina, MI, CHF, CVA, or kidney failure.¹⁰ The dental office can play a vital role in the detection of hypertension and maintenance care of the patient with hypertensive disease. The first dental office visit should include two BP readings spaced at least 10 minutes apart, which are averaged and used as a baseline. Before the clinician refers a patient to a physician because of elevated BP, readings should be taken at a minimum of two appointments, unless the measurements are extremely high (i.e., systolic pressure >180 mm Hg or diastolic pressure >100 mm Hg). The periodontal recall system is an ideal method for hypertension detection and monitoring. Almost three of every four adult patients with hypertension in the United States do not control their BP well enough to attain the goal of systolic pressure less than 140 mm Hg and diastolic pressure less than 90 mm Hg.¹¹ Lack of compliance with antihypertensive therapy is the primary reason for this failure. Dentists can help achieve greater success in managing hypertension by taking BP readings at each periodontal recall visit.

Periodontal procedures should not be performed until accurate BP measurements and histories have been taken to identify those patients with significant hypertensive disease. The time of day also should be recorded because BP varies significantly throughout the day.¹² Table 37-1 outlines appropriate medical referral or consultation and dental treatment modifications, depending on the patient’s stage of hypertension.

Dental treatment for hypertensive patients is generally safe as long as stress is minimized.10,13 If a patient is currently receiving antihypertensive therapy, consultation with the physician may be warranted regarding the current medical status, medications, periodontal treatment plan, and patient management. Many physicians are not knowledgeable about the nature of specific periodontal procedures. The dentist must inform the physician regarding the estimated degree of stress, length of the procedures, and complexity of the individualized treatment plan. Morning dental appointments were once suggested for hypertensive patients. However, recent evidence indicates that BP generally increases around awakening and peaks at midmorning.^12,14,15 Lower BP levels occur in the afternoon; therefore afternoon dental appointments may be preferred.

No routine periodontal treatment should be given to a patient who is hypertensive and not under medical management. For patients with systolic BP greater than 180 mm Hg or diastolic BP greater than 110 mm Hg, treatment should be limited to emergency care until hypertension is controlled. Analgesics are prescribed for pain and antibiotics for infection. Acute infections may require surgical incision and drainage, although the surgical field should be limited because excessive bleeding may be seen with elevated BP.

When treating hypertensive patients, the clinician should not use a local anesthetic containing an epinephrine concentration greater than 1 : 100,000 nor should a vasopressor be used to control local bleeding. Local anesthesia without epinephrine may be used for short procedures (<30 minutes). In a patient with hypertensive disease, however, it is important to minimize pain by providing profound local anesthesia to avoid an increase in endogenous epinephrine secretion.10,13

The benefits of the small doses of epinephrine used in dentistry far outweigh the potential for hemodynamic compromise. The smallest possible dose of epinephrine should be used, and aspiration before injection of local anesthetics is critical. Intraligamentary injection is generally contraindicated because hemodynamic changes are similar to intravascular injection.¹⁶ If the hypertensive patient exhibits anxiety, use of conscious sedation in conjunction with periodontal procedures may be warranted¹⁷ (see Chapter 36).

Beta-adrenergic receptor antagonists, or β-blockers, are typically used to treat hypertension (Table 37-2). β-blockers are either cardioselective, blocking only β-1 cardiac receptors (β1 receptors), or nonselective, blocking both β-1 cardiac receptors and β-2 peripheral receptors (β2 receptors). Epinephrine, an α-adrenergic and β-adrenergic agonist, produces an increase in heart rate through direct stimulation of cardiac β-1 receptors. Epinephrine also stimulates α-adrenergic receptors, producing vasoconstriction of arteries, as well as β-2 receptors, causing vasodilation of skeletal muscle arterioles. Administration of local anesthetics containing epinephrine to patients taking nonselective β-blockers (e.g., propranolol, nadolol) may cause elevated BP.¹⁸ Epinephrine-induced α-adrenergic stimulation results in vasoconstriction and increased BP. Because the patient’s nonselective medication has blocked the β-2 receptors, epinephrine will not stimulate the normal compensatory β-2 receptor–induced vasodilation. This may result in dramatically increased BP, followed by reflex bradycardia mediated by the vagus nerve and carotid baroreceptors. The end result is a patient with severe hypertension and bradycardia, resulting in a dangerous decrease in vascular perfusion and possible death. Because of this potential complication, epinephrine-containing local anesthetics should be used cautiously and only in very small amounts in patients taking nonselective β-blockers, with careful monitoring of vital signs.^10,18

The clinician should be aware of the many side effects of various antihypertensive medications. Postural hypotension is common and can be minimized by slow positional changes in the dental chair.¹⁰ Depression is a side effect of which many patients are unaware. Nausea, sedation, oral dryness, lichenoid drug reactions, and gingival overgrowth are associated with certain classes of antihypertensive agents.¹³

Ischemic Heart Diseases

Ischemic heart disease (Figure 37-1) includes disorders such as angina pectoris and myocardial infarction. Angina pectoris occurs when myocardial oxygen demand exceeds supply, resulting in temporary myocardial ischemia.⁵ Patients with a history of unstable angina pectoris (angina that occurs irregularly or on multiple occasions without predisposing factors) should be treated only for emergencies and then in consultation with their physician. Patients with stable angina (angina that occurs infrequently, is associated with exertion or stress, and is easily controlled with medication and rest) can undergo elective dental procedures. Because stress often induces an acute anginal attack, stress reduction is important. Profound local anesthesia is vital, and conscious sedation may be indicated for anxious patients¹⁷ (see Chapter 36). Supplemental oxygen delivered by nasal cannula may also help prevent intraoperative anginal attacks.

Patients who treat acute anginal attacks with nitroglycerin should be instructed to bring their medication to dental appointments. Nitroglycerin should also be kept in the office emergency medical kit. For particularly stressful procedures, the patient may take a nitroglycerin tablet preoperatively to prevent angina, although this generally is not necessary. The patient’s nitroglycerin should be readily accessible on the dental tray in case it is needed during treatment. Because the shelf life of nitroglycerin is relatively short, the expiration date of the patient’s nitroglycerin should be noted, as should the expiration date of the nitroglycerin in the office’s emergency medical kit. Also, patients with angina may be taking longer-acting forms of nitroglycerin (tablet, patch), β-blockers, or calcium channel blockers (also used in treatment of hypertension) for prevention of angina. Restrictions on use of local anesthetics containing epinephrine are similar to those for the patient with hypertension. In addition, intraosseous injection with epinephrine-containing local anesthetics using special systems (e.g., Stabident, Fairfax Dental) should be done cautiously in patients with ischemic heart disease, because it results in transient increases in heart rate and myocardial oxygen demand.¹⁹

If the patient becomes fatigued or uncomfortable or has a sudden change in heart rhythm or rate during a periodontal procedure, the procedure should be discontinued as soon as possible. A patient who has an anginal episode in the dental chair should receive the following emergency medical treatment:

In recent years, nitroglycerin lingual spray formulations have been popular in hospital pharmacies because of the increased shelf life as compared to nitroglycerin tablets.²⁰ The lingual spray has been reported to provide a greater and more rapid vasodilation with a longer duration of action.^21,22 The convenience and advantages of a nitroglycerin lingual spray are appealing, but the accuracy of dose delivery has been questioned and warrants additional studies before it can be recommended to replace the known tablet regimen.²⁰

Myocardial infarction (MI) is the other category of ischemic heart disease encountered in dental practice. Dental treatment is generally deferred for at least 6 months after MI because peak mortality occurs during this time.²³ After 6 months, MI patients can usually be treated using techniques similar to those for the stable angina patient.

Cardiac (aortocoronary) bypass, femoral artery bypass, angioplasty, and endarterectomy have become common surgical procedures in patients with ischemic heart disease. If one of these procedures was performed recently, the physician should be consulted before elective dental therapy to determine the degree of heart damage or arterial occlusive disease, the stability of the patient’s condition, and the potential for infective endocarditis or graft rejection. Prophylactic antibiotics are not usually necessary for cardiac bypass patients unless recommended by the cardiologist.

Congestive Heart Failure

Congestive heart failure (CHF) is a condition in which the pump function of the heart is unable to supply sufficient amounts of oxygenated blood to meet the body’s needs.²³ CHF usually begins with left ventricular failure caused by a disproportion between the hemodynamic load and the capacity to handle that load. CHF may be caused by a chronic increase in workload (as in hypertension or aortic, mitral, pulmonary, or tricuspid valvular disease), direct damage to the myocardium (as in MI or rheumatic fever), or an increase in the body’s oxygen requirements (as in anemia, thyrotoxicosis, or pregnancy).

Patients with poorly controlled or untreated CHF are not candidates for elective dental procedures. These individuals are at risk for sudden death, usually from ventricular arrhythmias.²⁴ For patients with treated CHF, the clinician should consult with the physician regarding the severity of CHF, underlying etiology, and current medical management. Medical management of CHF may include use of calcium channel blockers, direct vasodilators, diuretics, angiotensin-converting enzyme (ACE) inhibitors, α-receptor blockers, and cardiotonic agents such as digoxin.^25,26 Each of these medications has potential side effects that may have an impact on periodontal therapy. Because of the presence of orthopnea (inability to breathe unless in an upright position) in some CHF patients, the dental chair should be adjusted to a comfortable level for the patient rather than being placed in a supine position. Short appointments, stress reduction with profound local anesthesia and possibly conscious sedation, and use of supplemental oxygen should be considered.^10,23

Cardiac Pacemakers and Implantable Cardioverter-Defibrillators

Cardiac arrhythmias are most often treated with medications; however, some are also treated with implantable pacemakers or automatic cardioverter-defibrillators.10,24,27 Pacemakers are usually implanted in the chest wall and enter the heart transvenously. Automatic cardioverter-defibrillators are more often implanted subcutaneously near the umbilicus and have electrodes passing into the heart transvenously or directly attached to the epicardium. Consultation with the patient’s physician allows determination of the underlying cardiac status, the type of pacemaker or automatic cardioverter-defibrillator, and any precautionary measures to be taken. Older pacemakers were unipolar and could be disrupted by dental equipment that generated electromagnetic fields, such as ultrasonic and electrocautery units. Newer units are bipolar and are generally not affected by dental equipment. Automatic cardioverter-defibrillators activate without warning when certain arrhythmias occur. This may endanger the patient during dental treatment because such activation often causes sudden patient movement. Stabilization of the operating field during periodontal treatment with bite blocks or other devices can prevent unexpected trauma.

Infective Endocarditis

Infective endocarditis (IE) is a disease in which microorganisms colonize the damaged endocardium or heart valves.²⁸ Although the incidence of IE is low, it is a serious disease with a poor prognosis, despite modern therapy. The term infective endocarditis is preferred to the previous term bacterial endocarditis because the disease can also be caused by fungi and viruses. The organisms most often encountered in IE are α-hemolytic streptococci (e.g., Streptococcus viridans). However, nonstreptococcal organisms often found in the periodontal pocket have been increasingly implicated, including Eikenella corrodens, Aggregatibacter actinomycetemcomitans, Capnocytophaga, and Lactobacillus species.²⁹

IE has been divided into acute and subacute forms. The acute form involves virulent organisms, generally nonhemolytic streptococci and strains of staphylococci, which invade normal cardiac tissue, produce septic emboli, and cause infections that run a rapid, generally fatal course. The subacute form, conversely, results from colony formation on damaged endocardium or heart valves by low-grade pathogenic organisms; the classic example is rheumatic carditis consequent to rheumatic fever.

Since the last American Heart Association (AHA) publication on prevention of IE in 1997,³⁰ many have questioned the efficacy of antimicrobial prophylaxis to prevent IE in patients who undergo dental or other procedures and have suggested that the AHA guidelines should be revised.^31,32 Members of the Rheumatic Fever, Endocarditis, and Kawasaki Disease Committee of the AHA Council on Cardiovascular Disease in the Young, and a national and international group of experts on IE extensively reviewed data published on the prevention of IE. The committee concluded that only an extremely small number of IE cases might be prevented by antibiotic prophylaxis for dental procedures (even if such therapy was 100% effective). Consequently, the guidelines were changed and published in a 2008 report.³³ The new guidelines advise that IE prophylaxis should only be recommended for cardiac conditions with the highest risk of adverse outcome from IE (Box 37-1). For these patients, antibiotic prophylaxis is recommended for all dental procedures that involve manipulation of the gingival tissues, periapical tissues, or perforation of the oral mucosa. Antibiotic prophylaxis is not indicated for individuals on the basis of an increased lifetime risk of contracting IE.

The practice of periodontics is intimately concerned with the prevention of IE. However, bacteremia may occur even in the absence of dental procedures, especially in individuals with poor oral hygiene and significant periodontal inflammation. In fact, IE is much more likely to result from frequent exposure to random bacteremias associated with daily activities than caused by a dental procedure.³³ Thus the prevention of periodontal inflammation is paramount. The AHA states that patients who are at risk for IE should “establish and maintain the best possible oral health to reduce potential sources of bacterial seeding.” To provide adequate preventive measures for IE, the clinician’s major concern should be to reduce the microbial population in the oral cavity so as to minimize soft tissue inflammation and bacteremia.

Preventive measures to reduce the risk of IE should consist of the following:

The following guidelines should aid in the development of periodontal treatment plans for patients susceptible to IE:

Cerebrovascular Accident

A cerebrovascular accident (CVA), or stroke, results from ischemic changes (e.g., cerebral thrombosis caused by an embolus) or hemorrhagic phenomena. Hypertension and atherosclerosis are predisposing factors for CVA and should alert the clinician to evaluate the patient’s medical history carefully for the possibility of early cerebrovascular insufficiency and to be aware of symptoms of the disease. A physician’s referral should precede periodontal therapy if the signs and symptoms of early cerebrovascular insufficiency are evident.

To prevent a repeat stroke, active infections should be treated aggressively because even minor infection may alter blood coagulation and trigger thrombus formation and ensuing cerebral infarction. The clinician should counsel the patient about the importance of thorough oral hygiene.³⁶ Poststroke weakness of the facial area or paralysis of extremities may make oral hygiene procedures extremely difficult.³⁷ The clinician may need to modify oral hygiene instruments for ease of use, perhaps in consultation with an occupational therapist. Long-term chlorhexidine rinses may greatly aid in plaque control.

Dental clinicians should treat post-CVA patients with the following guidelines in mind: