Читать книгу Fundamentals of Fixed Prosthodontics - James C. Kessler - Страница 16

Patients who present with a history of cardiovascular problems require special attention. Hypertension affects nearly 50 million Americans.⁵ Thirty percent of those with high blood pressure (HBP) are not aware of having the condition; only 59% of them are being treated for it; and only 34% have their blood pressure controlled to recommended levels.⁶ Based on these statistics, it is probable that dentists see numerous patients with undetected or uncontrolled HBP, who are prime candidates for disastrous cardiovascular events. Therefore, dentists should check blood pressure of all patients at the first appointment and at subsequent visits. No patient with uncontrolled hypertension should be treated until the blood pressure has been lowered.

The 7th Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC-7) has revised guidelines that simplify blood pressure classification.⁶ There are two categories of hypertension:

 Stage 1: systolic blood pressure (SBP) ≥ 140–159 mm Hg or diastolic blood pressure (DBP) ≥ 90–99 mm Hg

 Stage 2: SBP ≥ 160 or DBP ≥ 100

In this simplified classification, prehypertension describes SBP = 120–139 mm Hg or DBP = 80–89 mm Hg. This replaces the category called high normal (SBP = 130–139, DBP = 85–89 mm Hg).⁶ Risk of a stroke or heart attack doubles for each 20/10 mm Hg incremental blood pressure increase above 115/75 mm Hg.⁷ For most patients, treatment should be performed only if blood pressure is below 140/90 mm Hg,^6,8 but in patients with diabetes or kidney disease, blood pressure should be lower than 130/80 mm Hg.^9,10

Epinephrine in local anesthetic is contraindicated for patients with severe cardiovascular disease but not for patients with mild-to-moderate forms of the disease if the number of carpules used is limited to two or three.⁶ The rationale is that lessening of pain will decrease the endogenous release of epinephrine, which could be 20 to 40 times greater if the patient becomes stressed by pain.¹¹ Retraction cord, however, does not provide any such potential benefit; therefore, cord containing epinephrine is contraindicated. Because of the availability of numerous alternatives for hemostasis and sulcus enlargement, the use of epinephrine-impregnated cords is not warranted.⁶

Patients on oral anticoagulant therapy are the most likely to experience hemorrhagic problems during dental treatment. ¹² They may be taking anticoagulants for a variety of reasons: prosthetic heart valves, myocardial infarction (MI), stroke (cerebrovascular accident [CVA]), atrial fibrillation (AF), deep venous thrombosis (DVT), or unstable angina.¹³ The two most widely used coumarin derivatives are warfarin sodium (Coumadin [Bristol-Myers Squibb]) and bishydroxycoumarin (dicumarol), both of which are vitamin K antagonists. ¹²

Anticoagulation level is measured by the international normalized ratio (INR). A patient whose blood coagulates normally would have an INR of 1.0.¹³ Increasing the anticoagulant effect increases the INR.¹² The INR range recommended by the American College of Chest Physicians¹⁴ and endorsed by the American Heart Association (AHA)¹⁵ is 2.0 to 3.0 in every situation mentioned previously, except for prosthetic heart valves, for which the INR range should be 2.5 to 3.5. The INR for artificial heart valves should not exceed 4.0.¹⁶

The patient’s physician should be consulted to learn why the patient is on anticoagulants,¹² the most recent INR value,^13,17 and when it was taken. Anticoagulant therapy is the responsibility of the physician, not the dentist. However, the physician may recommend stopping anticoagulant therapy 2 to 3 days prior to treatment, which is the traditional management of patients on anticoagulants, although the dental literature indicates that this may not be the optimal approach.¹⁸

An update of the recommendations by the AHA for prevention of infective endocarditis (IE) was issued in 2007.¹⁹ Guidelines were first published in 1955, and the most recent update before the present one was published in 1997. The current guideline greatly reduces the number of patients who should be premedicated, stating, “Only an extremely small number of cases of infective endocarditis (IE) might be prevented by antibiotic prophylaxis even if it were 100% effective.” ¹⁹

Antibiotic prophylaxis for dental procedures now is recommended only for patients with cardiac conditions with the greatest risk of adverse outcome from IE¹⁹:

 Prosthetic heart valve

 Previous IE

 Congenital heart disease (CHD)

 Unrepaired cyanotic CHD

 CHD repaired with a prosthetic material for 6 months after repair

 Repaired CHD with residual defect at or near the prosthetic patch that would interfere with endothelialization

 Cardiac transplants that develop valvulopathy

For patients with these conditions, prophylaxis is recommended for all dental procedures that involve the gingiva, the periapical region of the teeth, or perforation of oral mucosa.

The antibiotic regimen now recommended is a single 2-g oral dose of amoxicillin for adults who are not allergic to penicillin, 30 to 60 minutes before the procedure.¹⁹ There is no need to prescribe a follow-up dose after the procedure. If the patient is allergic to penicillin, 600 mg clindamycin or 500 mg azithromycin or clarithromycin may be substituted. If none of these is acceptable, consult the patient’s physician or the guidelines article in the June 2007 issue of the Journal of the American Dental Association.¹⁹

Patients with valvular dysfunction from rheumatic heart disease (RHD),²⁰ mitral valve prolapse (MVP) with valvular regurgitation,²¹ systemic lupus erythematosus,²² and valvulopathy resulting from the diet medication fenfluraminephentermine (“fen-phen”)²³ were once indicated for antibiotic prophylaxis, but following the 2007 guidelines set by the AHA, they no longer require premedication.¹⁹ Most unrepaired congenital heart malformations still do require antibiotic prophylaxis.¹⁹ Patients with cardiac pacemakers do not require prophylaxis.¹⁹

With regard to artificial joints, the American Dental Association (ADA) states, “Antibiotic prophylaxis is not indicated for dental patients with pins, plates or screws, nor is it routinely indicated for most dental patients with total joint replacements. However, it is advisable to consider premedication in a small number of patients who may be at risk of experiencing hematogenous total joint infection.”²⁴ For those patients not allergic to penicillin who do require premedication, 2 g amoxicillin taken orally 1 hour prior to the dental procedure is the antibiotic of choice. For variations of this regimen, the reader is referred to the advisory statement in the July 2003 issue of the Journal of the American Dental Association.²⁴

Patients who are on an antibiotic regimen prescribed to prevent the recurrence of rheumatic fever are not adequately premedicated to prevent IE.¹⁹ It is very possible that these patients will have developed strains of microorganisms that have some resistance to amoxicillin. If they require prophylactic antibiotic coverage, it would be wise to prescribe a different type than the one they are taking. Tetracyclines and sulfonamides are not recommended.