December 9, 2004
Evaluation of and Treatment Considerations for the Dental Patient With CARDIAC Disease
"Do you have any history of cardiac disease?" A positive response to this question on the health history is only the beginning of an appropriate evaluation of the patient's cardiac status. Focused questioning, along with an understanding of the nature and categories of cardiac disease, allow the dentist to better evaluate the patient's preoperative and intraoperative cardiac considerations, and to obtain a more accurate medical consultation when indicated.DESPITE ADVANCES in both prevention and treatment, cardiac disease remains the most common cause of death in the United States (38.5% of all deaths, or 1 of every 2.6 deaths). It is estimated that 20 million Americans are now living with some aspect of this disease.1 Dentists called upon to treat these patients must be able to render safe, appropriate and effective treatment with full consideration of the patient's cardiac condition.
A positive response on the medical history questionnaire to the question, "Do you have heart disease?" is only the first step in obtaining an accurate picture of cardiac status. Further questioning may elicit a complex cardiac history and a bewildering array of medications, and, often, even the patient is uncertain as to the true nature of his or her disease. New medications and rapid changes in interventional therapies may make the patient's cardiac condition seem more serious than it actually is. Conversely, casual assumptions, coupled with a too brief review of the medical history, may result in less than optimum care and unnecessarily increase the risk of a perioperative or postoperative cardiac event.
Thankfully, accurate preoperative assessment of the nature and severity of the patient's cardiac disease (for purposes of evaluating the cardiac risk during dental treatment) can generally be determined by a careful medical history and review of symptoms. This knowledge, coupled, if indicated, with some basic physical observations (Table 1), will also facilitate communication between dentist and physician if a medical consultation is deemed necessary; and, thus, the usefulness of the resulting medical consult will be enhanced. In addition, medical consultations are always more productive when the treating dentist is able to propose a treatment plan with appropriate modifications regarding cardiac disease to the consulting physician rather than the other way around. Both patient and dentist will benefit when the treating dentist is confident in his or her assessment of the need for limitations (or lack of) in treatment.
Physical Observation (The following may be useful in determining patient's cardiac status.)
Though there are many causes of cardiac disease (congenital, coronary artery disease, hypertension, inflammatory and immunologie myopathy, alcohol and drug abuse, etc.), it is important to understand that cardiac disease manifests itself in four broad categories: ischemic, valvular, arrhythmic and myopathie (congestive heart failure). While cardiac patients often present with more than one category of disease, evaluating them separately allows for a clearer understanding of the extent of the disease.
Below, each of these categories is presented with a brief discussion of its etiology, pathology, common presenting medical history (including the types of medication generally used to treat the disease), and relevant signs and symptoms depending upon the degree of impairment. Careful review of this material will enable the practitioner to accurately assess the nature of the disease and its degree of severity.
This particular form of heart disease refers to a lack of blood flow and/or oxygen to the heart muscle from blockage or stricture of the coronary arteries as the result of atheromas, or plaques. The etiologies of atherosclerotic disease are generally believed to be the result of hyperlipedemia, hypertension, hypercoagulability, hyperglycemia and/or smoking. One possible model of the formation of atheromatous plaques considers them to be an inflammation of the vascular intima, which may have sources other than atherosclerotic arteries, including systemic inflammation (for example, connective tissue diseases) and local infections (for example, gingivitis, prostatitis, bronchitis, urinary tract infections and gastric inflammation).
Patients with a history of ischemic disease may present with no history of symptoms or treatment, but usually report a past or present history of angina (chest pain, pressure or burning, often with radiation to the arm, throat or jaw-occasionally, jaw pain alone may be angina mimicking odontaglia), myocardial infarction (MI), angioplasty and stent placement, or coronary artery bypass graft surgery (CABG). Symptoms may include angina on exercise (known as stable angina) or even rest (unstable angina). Further questioning may reveal the use of occasional or frequent sublingual nitroglycerine to relieve the symptoms.
Some Common Medications Used for Ischemic Disease
Common medications used to treat ischemic disease are listed in Table 2, and may aid categorizing the disease. It's worth noting that some medications are useful for more than one category of cardiac pathology.
Chairside evaluation of these patients should be made by taking a careful history of medications and procedures, with special attention paid to the history of chest pain during exercise. While no absolute surety is possible, the degree of exercise tolerance before angina is one marker of the severity (or lack of) ischemic cardiac disease. Patients who have chest pain on "less than ordinary activity"2 (for example, one flight of stairs) and/or frequent use of sublingual nitroglycerin are at significant risk for angina or even myocardial infarction during treatment; and treatment should be deferred until appropriate medical stabilization is obtained.3
Patients with unstable angina should immediately be referred for further evaluation. Special attention should be paid to those patients with a history that includes a recent change of symptoms, medication regimen and/or recent cardiac procedures (angioplasty, stent, CABG), as their current status may be in doubt. Patients with a history of cardiac disease, especially ischemic cardiac disease, who are being followed by a physician, will generally have regularly scheduled, periodic stress tests. Valuable information and increased confidence in cardiac status may be obtained by determining the date of the last stress test, and whether the results reflected any significant improvement in the patient's cardiac status, or, instead, resulted in a change in medication or a suggestion for further workup or procedure (the latter result being a cause for concern).
As a general rule, elective treatment should be deferred for six months post MI and three months post CABG. Should treatment need to be rendered before this interval, or if any uncertainty still exists regarding the patient's cardiac status, medical consultation is indicated.
Treatment considerations for these patients is directed at avoiding increasing cardiac oxygen demand-generally, in the dental chair, avoiding increased tachycardia by limiting the use of epinephrine-containing drugs and limiting as much as possible the stress associated with dental treatment. Patients who use nitroglycerin should have that available. Nasal oxygen, with or without nitrous oxide, is a useful adjunct if tolerated.
Mitral, aortic, pulmonary or tricuspid heart valve disease is a disruption in the function of the heart valves that contribute to efficient action of the heart as a pump. The etiology of valvular disease may be congenital, infectious or inflammatory, degenerative, secondary to ischemic heart disease or age-related.
The history will be positive for valve disease, heart murmur, and/ or mitral valve prolapse, and may include cardiac valve surgery or even valve replacement. The need for preoperative prophylaxis must be addressed. Patients with valvular replacement may be taking anti- coagulation medication or medication to decrease clotting (Table 3).
Some Anticoagulant Medications-Valvular Disease, Atrial Fibrillation
Patients with valvular disease may also have associated arrhythmias and be at risk for or have some degree of congestive heart failure (see below). Valvular disease without further sequelae should not need alterations in the normal dental treatment plan beyond appropriate premedication if indicated and the standard considerations associated with the use of anti-thrombotic medications and dental treatment.
Arrhythmias may occur in the otherwise healthy heart. Arrhythmias, or disturbances of cardiac rhythm, imply a deviation from the normal pattern (sinus rhythm). They may be intrinsic, or they may be caused by stress, smoking, alcohol or caffeine, or other triggers. However, they are often associated with the sequelae of cardiac disease-damaged myocardium, previous or concurrent infarction, or valvular disease.
During an arrhythmia, the heart may beat too rapidly (tachycardia); too slowly (bradycardia); or it may beat irregularly. This can cause the heart to be unable to pump blood effectively; and the blood pressure may drop to a level that is life threatening. Patients with these problems will give a positive history of arrhythmia-skipping be\ats, fluttering sensation in the chest (palpitations), light-headedness, a fainting spell (syncope), chest pain or shortness of breath.
Although arrhythmias may go unnoticed, they can be serious. Patients who admit to a history of arrhythmias may have had a 24- hour Holler or other type of ambulatory cardiac monitoring to determine the incidence and frequency of arrhythmias. Diagnostic and therapeutic regimens may vary from none at all to avoidance of triggering factors, medication (Table 4), invasive cardiac electrophysioloeical testing and radiofrequency ablation (destruction of areas of the myocardium associated with the arrhythmia), and placement of an internal pacemaker and/or defibrillator.
Some Common Anti-arrhythmics
Further evaluation by history can be directed at determining the nature, site of origin and frequency of the occurrence of arrhythmia. Premature atrial or ventricular beats (PAC's, PVC's) are perhaps the most common arrhythmias sometimes associated with valvular disease (see above) and are generally benign and not treated. In general, certain common atrial arrhythmias, such as atrial fibrillation, are of minimal concern, beyond the requirement of anti-thrombotic medications (Table 4). Ventricular arrhythmias, especially ventricular tachycardias, are generally looked upon with more concern and have the potential to be life threatening.
Treatment modifications usually need only be limited to avoiding arrhythmic triggers, chiefly avoiding overuse of epinephrinecontaining anesthetics events so as to prevent an epinephrineinduced tachycardia. Some cardiologists advise premedication prophylaxis for the first three to six months post pacemaker/defibrillator placement.
Congestive Heart Failure
Congestive heart failure (CHF) is a condition in which the heart is unable to pump enough blood to adequately supply physiological requirements. This may be a result of cardiac ischemic, myocardial damage due to infarction, valvular disease, untreated hypertension, cardiomyopathy due to viral or other causes, or structural changes (for example, left ventricular hypertrophy). The patient's medical history will often reflect these events. Various drugs are used to treat congestive heart failure (Table 5). Recently, pacemaker/ defibrillator therapy has been used as well.
Congestive Heart Failure
WHO Definitions And Classifications of Blood Pressure Levels
Patients with CHF may evince the following symptoms: fatigue; shortness of breath, especially while laying flat or with any exertion; swollen legs or ankles; weight gain; decreased urination during the day and increased urination at night. The degree of failure is reflected in the severity-or lack-of the above symptoms. Patients in mild-to-moderate failure should require no significant treatment changes other than judicious use of epinephrine, as an epinephrine-induced tachycardia can interfere with left ventricular filling and exacerbate the CHF. Care should be taken to identify any other antecedent cardiac pathology present.
Hypertension, thought to afflict more than 50 million Americans, is a syndrome with multiple causes; but it is often both a cause and co-morbid factor in heart disease and, so, deserves mention here.
Hypertension is generally defined as an arterial pressure of greater than 140/90 mmHg for an extended period of time. Untreated, it can lead to renal disease and stroke, as well as cardiac disease. Patients with uncontrolled hypertension should seek medical care prior to treatment whenever possible. And elective treatment should be deferred for patients with severe hypertension. Judicious use of epinephrine is appropriate for those who are under treatment and/or with mildly elevated pressures (Table 6).
Regarding the phrase "judicious use of epinephrine," the joint conference of the American Heart Association and the American Dental Association noted, "the typical concentrations of vasoconstrictors contained in local anesthetics are not contraindicated with cardiovascular disease so long as preliminary aspiration is practiced, the agent is injected slowly, and the smallest effective dose is administered."7
It should be understood that the exact amount of epinephrine that is safe to use on the "cardiac" dental patient is dependent upon the specific type and degree of cardiac disease present, as well as the patient's weight and age. However, it is generally accepted that the total dosage of epinephrine be limited to 0.04 mg within a 15- minute period in cardiac risk patients.3,4 This equates to approximately two cartridges of 1:100,000 epinephrine-containing local anesthetic. Levonordefrin (neo-cobefrin) is considered to be roughly one-fifth as effective a vasoconstrictor as epinephrine and is, therefore, used in a 1:20,000 concentration and should be considered to carry the same clinical risks as 1:100,000 epinephrine.4,7 The benefits of maintaining adequate anesthesia for the duration of the procedure far outweighs the risks in almost all patients with a cardiac history. This general rule is even further enhanced if a thorough preoperative cardiac history is obtained and appropriately evaluated. Careful case selection, as outlined above, will allow the dentist to proceed with treatment with increased confidence of a positive and safe outcome.
The author thanks Arthur Meltzer, M.D., and Larry Inra, M.D., for their assistance in reviewing this article.
1. Cardiovascular Disease Statistics, American Heart Association Statistics 2001. American Heart Association Publication.
2. Cecil Essentials of Medicine, Fourth Edition. WB Saunders Co. 1997:11.
3. Roser S, McCabe J. Evaluation and Management of the Cardiac Patient for Surgery. In Oral and Maxillofacial Surgery Clinics of North America. August 1998:429-443.
4. Pearson T, et al. Markers of inflammation and cardiovascular disease. Circulation 2003;107:499. AHA/CDC Scientific Statement.
5. Budenz AW. Local anesthetics and medically complex patients. J California Dental Association (online) August 2000.
6. The Merck Manual, 16th Edition. Merck Labs. 1992:367-555.
7. Working Conference of ADA and AH A on Management of Dental Problems in Patients with Cardiovascular Disease. JADA 1964;68:333- 42.
Frederick M. Lifshey, D.D.S.
Copyright Dental Society of the State of New York Nov 2004