American College of Cardiology/ American Heart Association updated guidelines for peri-operative care cardiovascular evaluation prior to noncardiac surgery: implications for dental hygiene treatment in post-myocardial infarction.

Introduction

In 2007, the American College of Cardiology Foundation and the American Heart Association (ACC/AHA) jointly updated clinical practice guidelines to assist health care providers in clinical decision making regarding oral care for clients with serious cardiovascular (CV) disorders. For the client who previously suffered myocardial infarction, they recommend determining functional capacity (FC), rather than relying on time passed since the event, to assess cardiac risks during oral care. The guidelines are written specifically for surgical procedures, including head and neck surgery, but include a category of"superficial procedures" that could encompass dental hygiene periodontal debridement. Recommendations include appropriate pharmacologic therapy that should be maintained during surgical procedures.

The client with a history of a myocardial infarction (MI) or severe cardiovascular disease (CVD) requires a thorough assessment to identify potential risks for a medical emergency during oral procedures. Warnings in previous dental literature have included delaying elective oral procedures for time periods ranging from one month to six months. (1,2) The ACC Foundation recently joined AHA to update the guidelines published in 20023 and corrected in 20064 for physicians and other health care professionals regarding noncardiac surgical procedures for individuals with a history of significant coronary artery disease (CAD, myocardial infarction, angina, etc.) and other serious CV conditions. (5) They apply to planning oral care procedures and are intended for nonphysician caregivers involved in the pre-operative, operative and post-operative care of individuals undergoing noncardiac surgery.

The 2007 guidelines provide a framework for considering cardiac risks during noncardiac surgical procedures (e.g., head and neck surgery or oral procedures involving significant bleeding of long duration or increased stress). The document attempts to define practices that meet the needs of most patients in most circumstances. For example, the writing group for the ACC/AHA stressed that patient adherence to the prescribed medical regimen and lifestyle changes is an important aspect of evaluation. Prescribed courses of treatment are effective only when followed by the client. Since noncompliance may adversely affect treatment outcomes, oral health care providers should question the client regarding compliance. This can be facilitated by obtaining the prescribed therapy and lifestyle changes recommended during consultation with the cardiologist monitoring the client care. Follow-up questions about compliance with the prescribed regimen and lifestyle changes should be included in the medical history review and might address smoking, exercise, and serum cholesterol levels. The exercise regimen could directly relate to FC, a key determinant of cardiac risks that should be assessed when potentially stressful oral care is planned.

Preoperative Evaluation

The purpose of preoperative evaluation is to determine the client's current medical status; make decisions concerning the evaluation, management and risk of cardiac problems over the entire perioperative period; and provide a clinical risk profile that the patient, primary physician and nonphysician caregivers can use in making treatment decisions that may influence short- and long-term cardiac outcomes. (5)

Major Clinical Predictors

The major, intermediate and minor clinical predictors of increased perioperative CVD risk appear in Box 1. A major predictor, myocardial infarction (MI) is considered acute if it occurred less than seven days previously; recent if more than seven days but less than one month. Angina is considered unstable or severe if not relieved by rest.

2002 American College of Cardiology/American Heart Association Guidelines

The 2002 guidelines introduced changes that help elucidate the 2007 revision and include the evaluation of FC to determine cardiac risks during noncardiac surgery or related procedures. (3) Various surgical procedures were classified as having low, intermediate or high risk. Oral surgery was determined to be an intermediate risk procedure (cardiac risk less than five percent), and superficial procedures were at low risk (cardiac risk less than one percent). Procedures of long duration or causing excessive blood loss increased cardiac risk. Guidelines published in 1996 had included an increased risk the first three to six months after MI, which the 2002 document revised to 30 days. Current medical management for MI requires risk stratification during convalescence. If a recent stress test does not reveal poor myocardial function, the likelihood of reinfarction during noncardiac surgery is low, and it is reasonable to delay elective surgery (or periodontal debridement) for four to six weeks after the MI and determine FC before proceeding with professional oral care. The decision to proceed with treatment would be made in consultation with the cardiologist, a recommendation retained in the 2007 guidelines.

Box 1. Clinical Predictors of Increased
Cardiac Risk

Major
Unstable coronary syndromes
Acute or recent MI with evidence of ischemic risk
   Unstable or severe angina
   Decompensated heart failure
Significant arrhythmias
   High grade atrioventricular block
   Symptomatic ventricular arrhythmias with underlying
   cardiac disease
   Supraventricular arrhythmias with uncontrolled ventricular
   rate
Severe cardiac valve disease

Intermediate
Mild angina pectoris
Previous MI by history or EKG
Compensated or prior heart failure
Diabetes mellitus (particularly Type 1)
Renal insufficiency

Minor
Advanced age
Abnormal ECG (left ventricular hypertrophy, left bundle-ranch
block, ST-T abnormalities)
Rhythm other than sinus (e.g. atrial fibrillation)
Low FC (e.g. unable to climb one flight of stairs with a
bag of groceries)
History of stroke
Uncontrolled systemic hypertension

Source: Fleisher LA, Beckman JA, Brown KA et al ACC/AHA 2007
guidelines on perioperative cardiovascular evaluation and care for
noncardiac surgery: a report of the American College of
Cardiology/American Heart Association Task Force on Practice
Guidelines. Circulation 2007:116(17):1971-96.

Emergency Care

The value of withholding emergency or elective surgery during the first 30 days after MI was supported by a 2005 study of sudden death in individuals at high risk who experienced MI and left ventricular dysfunction, heart failure or both. (6) This study of 14,609 patients revealed that seven percent had a CV event a median of 180 days after MI, with 903 dying suddenly and 164 resuscitated after cardiac arrest. The risk was highest in the first 30 days following MI (1.4 percent per month [95 percent confidence interval, 1.2 to 1.6 percent]) where 19 percent of all sudden deaths or episodes of cardiac arrest occurred and decreased to 0.14 percent per month after two years [95 percent confidence interval, 0.11 to 0.18 percent]. The risk was greatest among those with the lowest left ventricular ejection fraction.

Functional Capacity (FC)

Surgery-specific cardiac risks in noncardiac surgery are related to two important factors: the type of surgery or procedure itself and the degree of stress associated with it. (5) Factors that help determine cardiac risk include FC, age, comorbid conditions (e.g., diabetes mellitus, peripheral vascular disease, renal dysfunction, chronic pulmonary disease) and the type of surgery to be performed. The 2007 guidelines deemed head and neck procedures an intermediate risk. FC is expressed in metabolic equivalent (MET) levels. Table I shows activities and their METs. Baseline MET levels are equivalent to aerobic demands for various activities. Perioperative cardiac risks are increased when the client is unable to meet a four-MET capacity. (3,5) For the client with a history of MI, the medical history review should include questions to establish the convalescence or recovery following the MI. Recovery can be measured by the ability to achieve a minimum level of four METs during normal daily activities. Oral procedures should be delayed for a client unable to attain four METs until further medical testing has been completed to quantify the level of cardiac risk in treatment. (3,5) Referral to the cardiologist is appropriate to determine when the cardiac status is sufficiently controlled and oral care can be provided. It is possible that the medical caregiver will recommend cardiac revascularization (stents, balloon angioplasty) before noncardiac surgical procedures.

Noncardiac surgery, including periodontal debridement, is generally safe for individuals with neither major nor intermediate predictors of clinical risk (Box 1) and moderate or excellent FC (four METs or greater). For those with intermediate predictors of clinical risk and moderate to excellent FC, head and neck surgery poses little likelihood of perioperative death or MI. (5)

Hypertension

Blood pressure levels of [greater than or equal to] 180/110 mm Hg have an ASA 4 risk classification (oral treatment is contraindicated) for oral procedures. (3,7) If surgery is urgent, according to the 2007 guidelines, rapidly acting drugs such as beta blockers can be given to allow effective control in a matter of minutes to hours. (5) Use of selective beta-blocking agents poses less cardiac risk; however, if the dental client takes selective beta-blocking drugs, vasoconstrictor concentrations should be limited to two or fewer cartridges of 1:100,000. (1)

Concurrent Drug Therapy

There is evidence that statins should be continued through noncardiac surgery. (5,8) Discontinuation prior to surgery could lead to increased CV events. The 2007 guidelines also advocate stopping antiplatelet therapy (aspirin [ASA], clopidogrel [Plavix]) for as short a time as possible for patients who have undergone coronary artery stent placement in preparation for noncardiac surgery. A coronary stent is a wire mesh tube implanted permanently into a blocked artery to restore blood flow to the cardiac muscle. Patients can receive either a drug-coated stent or a bare metal stent. A rare but serious risk for both types of devices is stent thrombosis, the formation of a blood clot inside the stent within months following implantation that can lead to coronary artery occlusion and MI or death. To reduce the risk of stent thrombosis, patients are prescribed dual antiplatelet therapy (ASA, Plavix). Aspirin is generally taken for life and Plavix for months to years. For patients who have received bare metal stents, dual antiplatelet therapy should be continued for six weeks after the procedure and noncardiac surgery delayed for this six-week period. (5,8) Since late stent thrombosis is significant for drug-coated stents, and premature discontinuation of therapy significantly increases the risk of CV events (e.g., death, MI), the minimum duration of dual antiplatelet therapy is 12 months after implantation. Elective surgery or procedures involving significant bleeding should be delayed until after this one-year period.

In February 2007, AHA, ACC, the Society for Cardiovascular Angiography and Interventions, the American College of Surgeons and the American Dental Association (ADA) published a consensus opinion about drug-eluting stents and antiplatelet therapy. (9) The advisory document states that health care providers who perform invasive or surgical procedures (dentists, specialists, dental hygienists) and are concerned about periprocedural and postprocedural bleeding should contact the patient's cardiologist regarding the patient's antiplatelet regimen and discuss optimal patient management before discontinuing the antiplatelet medications. Given the importance of antiplatelet medications in post-stent implantation to minimize the risk of stent thrombosis, the medications should not be discontinued prematurely. The current ADA policy for antiplatelet agents following stent placement can be accessed at www.ada.org A-Z Topics. (10)

Dental Management Considerations

To provide safe care when CVD is present, oral health care providers must understand the pathophysiology of the disease, treatment regimens advised and the impact of both on the client's ability to receive oral care and withstand associated stress on the CV system. Table II summarizes management considerations for the dental hygienist.

Stress Reduction

The main issue in providing oral care services to a client with CVD is reducing stress-related physiologic responses. Anxiety, fear and pain can provoke release of endogenous catecholamines (adrenalin) from the adrenal gland, which increases heart rate and causes vasoconstriction and increased blood pressure. This illustrates the need for adequate pain control. For anxious clients, an anti-anxiety agent such as a benzodiazepine or nitrous oxide (35 percent N[O.sub.2]/65 percent [0.sub.2]) is useful. (11) Postprocedure analgesia should be considered; acetaminophen (APAP) is a safe drug in this situation. Opioid-APAP combination analgesics contribute to CV stability and can be used on a short-term basis at the lowest effective dose. (11) There are no controlled or randomized clinical trials that define the process of risk stratification for dental procedures. One study demonstrated that dental procedures in general are comparable to a spectrum of medical procedures (dermatology, neurology, occupational medicine, ophthalmology, other) provided in an ambulatory setting in terms of cardiac risk, which is low or very low. (12)

Physical Evaluation

Medical History. A complete medical history (defined as having the client complete a new form) should be taken annually, as changes can occur in CV function. It should be reviewed with the client at each appointment to determine the degree of disease control and compliance with medical therapies. Recent changes in CV status are important as they may represent loss of disease control. The client should be questioned about compliance with recommended therapy and whether cardiac medications are being taken as prescribed. Medications and herbal supplements should be investigated in a drug reference with attention paid to potential adverse effects such as gingival hyperplasia (calcium channel blockers), xerostomia (numerous agents), and bleeding complications (warfarin, aspirin, clopidogrel [Plavix], others). Observation of facial color and texture may reveal cyanosis or edema, which are signs of uncontrolled disease. Obesity can be relevant to serum cholesterol levels, increased inflammatory chemicals in the circulation and hypertension. Increased serum cholesterol is associated with CAD, so questioning about recent blood cholesterol may reveal increased risk for CVD. Use of tobacco should be investigated and the client asked if there is interest in a tobacco cessation program, with appropriate counseling offered or referral made.

Functional capacity. The medical history interview should seek to determine the client's FC. The ability to perform daily tasks that require cardiac reserve is significantly related to cardiac risk during treatment and correlates well with maximum oxygen uptake by treadmill testing. (3) Ask the following questions about abilities that meet the four-MET level:

1. Can you walk up a flight of stairs carrying groceries?

2. Can you run a short distance?

3. Can you participate in recreational activities such as doubles tennis, play nine holes of golf or dance for at least five minutes?

Receiving a positive response can establish if the client's FC is adequate. The client who is classified as high risk due to an MI within the past two months, but who is asymptomatic (no recent angina, blood pressure <180/110) (1) and who runs for 30 minutes each day may need no further evaluation before initiating periodontal debridement or restorative dental procedures. (12) In contrast, a client without a history of CVD who has a sedentary lifestyle and fatigue, dyspnea and chest pain on exertion that suggest undiagnosed CVD should be questioned about FC. (5) If unable to meet the four-MET demand, a preoperative medical consultation is indicated. (5)

Vital signs. A blood pressure value [greater than or equal to] 180/110 is a reliable indicator of CAD and holds an ASA risk classification of 4. No elective oral care should be provided, and the client should be referred for medical evaluation to control blood pressure before treatment is considered safe. (7) Vital signs including blood pressure, pulse rate and qualities, and respiratory rate and qualities should be assessed at each appointment rather than once yearly, as is recommended for the general client. (13) Normal pulse rate is 60-100 beats per minute, and the quality should be regular. (1) Respiration rate is 12-16 breaths per minute and should be noiseless. (1) For clients taking ant/hypertensive medication, blood pressure control should be monitored and values reported to the client. About 50 percent of those taking ant/hypertensive drugs have controlled blood pressure (<140/90) so the clinician should not fail to monitor blood pressure simply because medication is being taken. (14) A rapid, irregular pulse rate (>130 bpm) is a warning sign for MI and the most common sign preceding MI. MI can damage cardiac muscle and lead to congestive heart failure (CHF), also referred to as heart failure (HF). Left-side HF, when uncontrolled, results in fluid accumulation in lungs. Respiratory rate increases because the client doesn't feel as though the lungs are absorbing enough oxygen, and respiratory sounds of congestion and coughing demonstrate fluid accumulation.

Appointment considerations. In general, long dental appointments should be avoided for the client who has CVD. Long appointments increase the stress on the CV system. Since blood pressure is lowest in the afternoon, it is thought that afternoon appointments are preferred. The client should be allowed to determine the best time of day when he or she is well rested.

Use of the Vasoconstrictor

For most oral procedures, the use of a local anesthetic (LA) to prevent pain (and subsequent client stress) is beneficial and provides a margin of safety in the cardiac client. In the absence of profound anesthesia, adrenalin-induced tachycardia with increased cardiac workload and oxygen requirements can precipitate coronary ischemia and angina pectoris. In some individuals, the event can progress to cardiac arrest. Although some clients may fear the "needle," studies show that even though a transient increase in blood pressure may be produced during LA administration, blood pressure decreases when the syringe is removed from the mouth. (15) The cardiac dose for a vasoconstrictor is no more than two cartridges of 1:100,000 epinephrine (equivalent to 1:20,000 levonordefrin) or four cartridges of 1:200,000 epinephrine. For the client taking a nonselective beta blocker, epinephrine should be limited to two or fewer cartridges of 1:100,000 epinephrine.(1) A study investigated the heart rate and rhythm in individuals with CVD undergoing minor oral surgery (tooth extraction, alveoloplasty, biopsy) under local anesthesia (lidocaine two percent with 1:100,000 epinephrine or bupivacaine 0.5 percent with 1:200,000 epinephrine). (16) Twenty of the 40 study subjects were being treated for CV conditions such as hypertension, angina, prior MI, conduction abnormalities and heart failure. Normal doses were given and ranged from the equivalent of 1.0 to 7.9 mL of LA with 1:100,000 epinephrine. Although arrhythmias were detected in 17 subjects, they were benign in character. The incidence of arrhythmia did not differ between subjects with or without CVD. More rhythm disturbances occurred preoperatively and intra-operatively than during LA administration with epinephrine. This was attributed to anticipatory anxiety and the stress of surgery. Consequently, 4.5 mL of a local anesthetic agent with epinephrine 1:100,000, or equivalent, can be administered safely when the FC is 4 METs or greater. (7) In addition, local anesthetic administration includes following safe principles of injection technique (use of aspirating syringe, slow injection).

Summary

For the client with a history of CVD, including a history of MI, who shows no evidence of cardiac symptoms and is able to meet a four-MET demand during daily activities, and who has a systolic blood pressure less than 180 mm Hg and a diastolic pressure less than 110 mm Hg with a normal pulse and rhythm, oral procedures can be provided with little to no risk for a CV event. Adequate pain control is essential to reduce cardiac workload and achieve a successful treatment procedure. For the client with a recent history of MI who has undergone a recent stress test that does not reveal poor myocardial function, the likelihood of reinfarction during noncardiac surgery is low. In this client it is reasonable to delay elective surgery (or periodontal debridement) for four to six weeks after the MI and, in consultation with the cardiologist, determine that FC meets a four-MET level before proceeding with oral care. Management of care should include a thorough physical evaluation, appropriate stress reduction, and conservative use of a vasoconstrictor if local anesthesia is administered, taking care to prevent intravascular injection.

References

(1.) Little JW, Falace DA, Miller CS, Rhodus NL. Dental management of the medically compromised patient, 7th ed. St. Louis: Mosby Elsevier; 2008: DM-5, DM-3, 12.

(2.) Malamed SF. Medical emergencies in the dental office, 6th ed. St. Louis: Mosby Elsevier; 2007: 473.

(3.) Eagle KA, Berger PB, Calkins H, et al. ACC/AHA guidelines update for perioperative cardiovascular evaluation for noncardiac surgery: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Update the 1996 Guidelines on Perioperative Cardiovascular Evaluation for Noncardiac Surgery). J Am Coil Cardiol 2002; 39: 542-53.

(4.) ACC/AHA guideline update for perioperative cardiovascular evaluation for noncardiac surgery: correction. J Am Coil Cardiol 2006; 47(11): 2356.

(5.) Fleisher LA, Beckman JA, Brown KA, et al. ACC/AHA 2007 guidelines on perioperative cardiovascular evaluation and care for noncardiac surgery: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 2002 Guidelines on Perioperative Cardiovascular Evaluation for Noncardiac Surgery). Circulation 2007; 116 (17): 1971-96.

(6.) Solomon SD, Zelenkofske S, McMurray JJV, et al. Sudden death in patients with myocardial infarction and left ventricular dysfunction, heart failure, or both. N Engl J Med 2005; 352(25): 2581-8.

(7.) Pickett F, Terezhalmy G. Dental drug reference with clinical implications. Baltimore: Lippincott Williams & Wilkins; 2006: 146, 108.

(8.) Belden H. New guidelines have been issued related to the use of perioperative drugs for cardiac patients. Available at www.drugtopics.com/drugtopics/content/printContentPopup.jsp?id=484461. Accessed Mar. 16, 2008.

(9.) Grines CL, Bonow RO, Casey DE, et al. Prevention of premature discontinuation of dual antiplatelet therapy in patients with coronary artery stents. A science advisory from the American Heart Association, American College of Cardiology, Society for Cardiovascular Angiography and Interventions, American College of Surgeons, and American Dental Association, with representation from the American College of Physicians. Circulation 2007; 115: 813-8.

(10.) ADA.org:A-Z Topics. Drug-eluting stents (DES) and antiplatelet therapy educational document for dentists. Available at www.ada.org/prof/resources/topics/ antiplatelet_therapy.asp. Accessed Mar. 16, 2008.

(11.) Steinhauer T, Bsoul SA, Terezhalmy G. Risk stratification and dental management of the patient with cardiovascular diseases, part II: oral disease burden and principles of dental management. Quintess Intl 2005; 36(3): 209-27.

(12.) Becker L, Eisenberg M, Fahrenbruch C, Cobb L. Cardiac arrest in medical and dental practices. Implications for automated external defibrillators. Arch Intern Med 2001; 161: 1509-12.

(13.) American Dental Association Council on Dental Health and Health Planning and Bureau of Health Education and Audiovisual Services. Breaking the silence on hypertension: a dental perspective. J Am Dent Assoc 1985; 10: 781-9.

(14.) Chobanian AV, Bakris GL, Black HR, et al. The seventh report of the joint national committee on prevention, detection, evaluation and treatment of high blood pressure. National Heart, Lung and Blood Institute. J Am Med Assoc 2003; 289: 2560-78.

(15.) Gortzak RAT, Oosting J, Abraham-Inpijn L. Blood pressure response to routine restorative dental treatment with and without local anesthesia. Oral Surg Oral Med Oral Pathol 1992; 73:677-81.

(16.) Campbell JH, Huizinga PJ, Das SK, et al. Incidence and significance of cardiac arrhythmia in geriatric oral surgery patients. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1996; 82: 42-6.

Frieda Atherton Pickett, RDH, MS, graduated from Caruth School of Dental Hygiene, Baylor College of Dentistry in 1966 with a B.S.-Dental Hygiene Degree, and worked as a dental hygienist in general dentistry. In 1969, she entered the graduate program in Dental Hygiene Education, University of Missouri-Kansas City School of Dentistry, receiving her Master's Degree in 1970. Her teaching career includes over 30 years' experience. She has published widely in the oral health care literature and lectures throughout the country. She can be reached through www.friedapickett.com.

Table I. Activities and Metabolic Equivalents (3,5)

1 MET       Eat, dress oneself, use toilet
            Walk indoors around house
            Walk a block on level ground at 2-3 mph

4 METs      Light housework, dusting, washing dishes,
            move furniture
            Climb a flight of stairs carrying groceries
            Walk up a hill
            Walk on level group at 4 mph
            Run a short distance
            Participate in golf, bowling, dancing, doubles
            tennis

10 METs     Strenuous sports, basketball, skiing, singles
            tennis

Adapted from Fleisher LA et al. ACCIAHA 1007 guidelines update
for perioperative cardiovascular evaluation for noncardiac
surgery. Circulation 2007;116(17);1971-96.

Table II. Management Recommendations
for Post-MI Condition

Stress reduction
   Adequate pain control
   Pre-treatment benzodiazepine therapy
   Use of nitrous oxide/oxygen analgesia

Physical evaluation
   Complete medical history (new form) annually with questioning
   regarding compliance with medical therapy, tobacco cessation, etc.
   Investigate drugs, herbs being taken and consider side effects or
   drug effects that influence dental hygiene appointment.
   Extraoral exam and vital signs to identify signs and symptoms of
   uncontrolled disease
   Identify level of FC to ensure a minimum level of four metabolic
   equivalents before initiating oral procedures.
   No treatment if blood pressure ?180/110. Evaluate pulse rate and
   quality; assess respiratory qualities.
  Short appointments