Medical/Medication Complications in Oral Implantology

Are you currently being treated for high blood pressure, or have you been told by a health care professional that you have high blood pressure, or hypertension? image/No?

Hypertension is a highly prevalent cardiovascular disease, affecting over 50 million Americans and 1 billion people worldwide. An estimated 7.1 million deaths per year are attributable to hypertension, along with 62% of cerebrovascular disease and 49% of ischemic heart disease. Approximately 30% of adults with hypertension are unaware they have hypertension, and two thirds of patients treated are not controlled to blood pressure less than 140/90 mm Hg.4 The overall prevalence of hypertension is approximately 30% to 45% of the general population; however, a steep increase with aging is present.5 Untreated, undiagnosed, and uncontrolled hypertension is a serious problem in society today. Because implant dentists treat a high percentage of elderly patients, coupled with the high prevalence in the general population, incidence of treating patients with uncontrolled or undiagnosed hypertension is very high. This places the implant clinician at risk because intraoperative hypertensive episodes may result in cardiac arrhythmias with possible myocardial ischemia issues, which may lead to possible cardiovascular events such as myocardial infarction or cerebrovascular events.

Classification of Hypertension

In February 2014 the members of the eighth Joint National Committee (JNC8) on high blood pressure issued new guidelines for the treatment and management of high blood pressure in adults (Table 2.1). This report redefined treatment goals and thresholds for initiating treatment as well as a reevaluation of many common medications used to treat high blood pressure.6 For years, medical providers treated blood pressure to a goal of 120/80 mm HG based on the recommendations of JNC7. JNC8 examined five new critical blood pressure trials. The most compelling and reproducible outcome in all the trials was lowering the diastolic blood pressure to less than 90, which resulted in fewer cardiac events and a reduction in overall mortality.

TABLE 2.1

Blood Pressure Treatment Guidelines

Category Systolic (mm Hg) Diastolic (mm Hg) TREATMENT
Preoperative Intraoperative
Ideal <120 <80 None None
Prehypertension 120–139 80–89 Recheck, possible MD consultation Recheck, stress reduction protocol
Grade 1 hypertension 140–159 90–99 Recheck, possible MD consultation, (relative) Monitor, stress reduction protocol
Grade 2 hypertension 160–179 100–109 Recheck, MD consultation, (absolute)

Monitor, discontinue procedure, possible

ER referral

Hypertensive crisis >180 >110 Recheck, emergency care, (absolute) Monitor, abort immediately, emergency care

Additionally, JNC8 examined the medications used to treat blood pressure and concluded first-line treatments should be limited to four classes of medications; angiotension-converting enzyme inhibitor (ACEs), angiotension receptor blockers (ARBs), thiazide-type diuretics, and calcium channel blockers (CCBs). The implant clinician must have a thorough understanding concerning how hypertensive states may impact both surgical success and implant longevity.

Surgical/Implant Implications
Intraoperative elevated blood pressure.

The implant dentist and staff must be knowledgeable about the measurement, detection, and treatment of hypertension. The accurate measurement of blood pressure, along with a review of all medications including herbal and over-the-counter medications, should be an integral part of the implant consultation and examination. This information must be reviewed in detail with the patient prior to surgery. If an automatic blood pressure–monitoring system is being utilized, a manual sphygmomanometer should be available to manually verify abnormal readings. Elevated readings (>160/100) should be verified by manual techniques and the procedure discontinued until the blood pressure returns closer to the patient’s baseline or within a more acceptable range.

Orthostatic hypotension.

Hypertensive patients are more susceptible to orthostatic hypotension when brought from a supine to an upright position. This is caused by an excessive fall in blood pressure, which results in faintness, light-headedness, dizziness, confusion, or blurred vision. Resolution of this complication will occur rapidly upon placing the patient back in a supine position. Allowing patients to sit upright slowly will minimize these complications, especially after longer procedures and in susceptible patients. Unless a patient has a serious medical contraindication (e.g., congestive heart failure, renovascular disease, chronic edema), they should be instructed to hydrate prior to the surgical procedure. This may help reduce the occurrence of orthostatic hypotension.

Antihypertensive medications + NSAIDs.

The use of nonsteroidal antiinflammatory drugs (NSAIDs) has been shown to lessen the effectiveness of various antihypertensive medications by inhibiting prostaglandin production, leading to intraoperative hypertensive episodes. Blood pressure regulation is highly prostaglandin dependent, especially as it relates to kidney function through the vasodilatory effects. NSAIDs possess a higher degree of interaction with diuretics, ACE inhibitors, ARB inhibitors, and beta blockers, which may modify prostaglandin-dependent pathways more than drugs that alter non–prostaglandin-sensitive pathways such as calcium channel blockers and central acting drugs. Therefore, the interaction with hypertensive medications and NSAIDs result in a higher propensity to increase blood pressure.7 Studies have related approximately 50 million patients are being treated with antihypertensive therapy, and 12 million use NSAIDs concomitantly. However, the short-term use of NSAIDs has not been shown to have a clinically significant effect.8

Beta blockers.

The implant clinician must take into consideration that beta blockers may potentiate the cardiovascular effects of epinephrine used in local anesthetics. The nonselective beta-adrenergic drugs, such as propranolol (Inderal) and nadolol, pose the greatest risk of adverse interactions.9 The cardioselective beta blockers (Lopressor, Tenormin) carry less risk of adverse reactions. However, there is competitive clearance through the liver between both classes of beta blockers and the local anesthetic. This may lead to an increase in serum levels of the local anesthetic.10 To avoid intraoperative hypertensive episodes, decreasing the dose and increasing the time interval between epinephrine-containing injections is recommended.11

Calcium channel blockers.

These medications used to treat hypertension or congestive heart failure may lead to gingival hyperplasia around natural teeth or implants (similar to Dilantin). Additionally, this drug classification has been associated with erythema multiforme (a benign rash characterized by patches of red raised skin) and other types of oral ulceration. Gingival overgrowth can result in pain, gingival bleeding, and difficulty in mastication, especially around implant prostheses. The incidence of gingival hyperplasia is approximately 1.7% to 3.8% of patients taking calcium channel blockers.12

Multiple antihypertensive drugs.

Patients with difficult-to-control blood pressure may be prescribed multiple classes of antihypertensive medications. Even though these patients are being treated with various antihypertensive medications, they are prone to possible elevation and spikes in blood pressure. With these patients, the clinician should seek medical evaluation and consultation, which may include a postoperative blood pressure–monitoring plan.

Susceptibility to other cardiovascular events.

Severe hypertension or elevation in blood pressure may lead to angina pectoris, congestive heart failure, myocardial infarction, retinal hemorrhage, or even a cerebrovascular episode. These conditions may be precipitated by a rapid increase in blood pressure during a local anesthetic injection or the inherent stress associated with the surgical procedure. A stress reduction protocol is paramount with hypertensive patients.

Implant healing.

Cardiac disease (hypertension) may theoretically affect blood supply to the implant site and hence reduce survival or success. However, multiple studies have shown no evidence of early or late failure in hypertensive patients receiving dental implants.13,14

Complication Prevention
Stress reduction protocol.

With hypertensive patients the blood pressure should be controlled before and during elective dental implant treatment. Because blood pressure often rises prior to dental and surgical procedures, a preoperative stress control protocol is mandatory (Box 2.1).

 

Box 2.1

Stress Reduction Protocol

Premedication the night before a procedure (longer-acting benzodiazepine [diazepam 5–10 mg])

Early morning appointment

Explain entire procedure in detail

Sedation (Oral/IV)

Minimize waiting-room time

Duration of treatment not to exceed patient’s tolerance

Profound local anesthesia

Slow/aspiration LA administration

Sufficient postoperative pain management

IV, intravenous; LA, local anesthetic.

Monitoring.

Accurate assessment of intraoperative vital sign monitoring is extremely crucial to prevent complications. If elevated blood pressure (Stage 2) is present, postponement or medical consultation is indicated. When measuring blood pressure in the office, adhere to the following:

Allow the patient to sit for 3 to 5 minutes prior to obtaining blood pressure measurements.

If blood pressure is elevated, recheck after 5 minutes, changing arms.

Automatic blood pressure machines may report inaccurate readings in patients with a history of cardiac arrhythmia such as atrial fibrillation, which may also cause an erratic heart rate. Multiple measurements of the blood pressure should be taken, and if a significant variation exists, the blood pressure should be checked manually with a stethoscope and sphygmomanometer.

Position cuff at the patient’s heart level and make sure the cuff is snug, approximately 3 cm above the elbow.

Maintain antihypertensive therapy.

Patients under a physician’s care with antihypertensive medications should be instructed to comply with their medication protocol, especially the morning of surgery. If patients do not maintain their medication protocol, inherent intraoperative vital sign fluctuations may result. A patient should never alter any physician prescribed medication unless otherwise instructed by their physician.

Slow administration of local anesthetics.

Control of pain and anxiety is paramount in patients with hypertension because endogenous catecholamines (adrenaline and norepinephrine) are released in response to pain and stress. Catecholamines increase blood pressure and cardiac output, thus placing the patient at risk of a stroke or cardiac arrest. Slow administration and aspiration of local anesthetics containing epinephrine also will minimize potential complications. High blood pressure levels may have direct effects on cardiac output, total peripheral resistance, and mean arterial pressure. This may result in lowering of the heart rate (bradycardia), a decrease in blood pressure, and in extreme conditions cardiovascular failure resulting in cardiac arrest.

Reduction in the use of vasoconstrictors.

Especially in elderly patients, the indiscriminate use of local anesthesia with vasoconstrictor should be cautioned. Attention should be exercised with patients having a cardiac history, and the dose of vasoconstrictors like epinephrine should be reduced (<0.4 mg). This may lead to elevation in vital signs in hypertensive patients, which may possibly lead to cardiovascular events. A rule of thumb is 50% of the recommended maximum dose of local anesthetics can be given after 1 half-life of the local anesthetic.

Angina

image Do you have chest pain with exertion or have you been treated for angina? image/No?

Angina is defined as significant, painful chest pain as a consequence of exertion or stress. Angina pectoris is a form of coronary heart disease that is usually caused by arteriosclerotic heart disease. However, it may be caused by coronary artery spasm, severe aortic stenosis, aortic insufficiency, anemia, emboli, and hereditary connective tissue disease. The cause of angina is a discrepancy between the myocardial oxygen demand and the amount of oxygen being delivered through the coronary arteries. The classical symptom of retrosternal pain that often radiates to the shoulders, left arm, or mandible or to the right arm, neck, palate, and tongue is usually relieved by rest. Patients with a history of angina may be taking long-acting nitrates to prevent the occurrence of acute episodes. Sublingual or spray nitroglycerin is recommended for the treatment of acute episodes. When retrosternal pain occurs, myocardial infarction is part of the differential diagnosis. The pain is similar in region but is more intense and usually will not cease within 3 to 5 minutes. Risk factors for angina pectoris are smoking, hypertension, high cholesterol, obesity, and diabetes.

Surgical/Implant Implications
Acute angina attack.

In the event of an acute angina attack, immediate discontinuation of the surgical procedure should be completed with the administration of nitroglycerin tablets (0.3 to 0.4 mg) or sublingual nitroglycerine spray. Additionally, 100% oxygen should be given to the patient along with repositioning in a semisupine (45-degree) position. Vital signs should be monitored with evaluation for irregular heartbeats, which could indicate premature ventricular contractions as a result of myocardial ischemia. If the pulse remains irregular, medical assistance should be sought.

Stable vs. unstable angina.

The difference between stable and unstable angina must be understood. Stable angina relates to chest pain that is similar to past episodes of angina and is usually brought on by similar amounts of exertion or activity. It usually resolves within several minutes of rest or discontinuation of exerted activity. Nitroglycerin will most often relieve the chest pain.

Unstable angina is classified as chest pain or pressure with or without shortness of breath that is a change from the typical anginal pain symptoms the patient has been experiencing with exertion. Chest pain at rest or with minimal exertional activity can also be classified as unstable angina. Unstable angina or a myocardial infarction in the last 6 months would be an absolute contraindication to the use of local anesthetics with vasoconstrictors.

Complication Implication
Postnitroglycerin issues.

Nitroglycerin is a vasodilator that increases the blood supply to the heart and may lower systemic blood pressure. The net effect reduces the workload and oxygen demand of the heart, relieving chest pain. The side effects of nitroglycerin are important to recognize because the overall decrease in blood pressure may cause a decreased blood flow to the brain. Flushing of the face and shoulders along with severe headache is common. After administration, fainting is possible; therefore the patient should be sitting or lying in a supine position. As the heart attempts to compensate for decreased blood pressure, the pulse rate may increase to as much as 160 beats/min.

Complication Prevention
Decrease dental procedural stress.

It is important to minimize factors that can increase the heart rate, increase blood pressure, and subsequently increase myocardial oxygen demand. Stress reduction is critical to reduce catecholamine release, which may adversely impact the cardiac contributors to angina. It is important to initiate a stress reduction protocol to help alleviate any cardiac stress factors.

Use of nitrous oxide sedation.

Use of sedation, especially nitrous oxide (N2O), will reduce the possibility of angina attacks. N2O potentially can decrease coronary blood flow; however, studies have shown no cardiac morbidity.15 Use of N2O in patients with both a cardiac and pulmonary history such as chronic obstructive pulmonary disease (COPD) or emphysema should be avoided.

Hypertension treatment summary

Mild (relative): May undergo most nonsurgical dental procedures performed with normal protocol. General cardiac precautions are advised, such as vital signs monitoring, and patients are instructed to bring their own nitroglycerin to their appointment. Advanced restorative procedures and minor implant surgery are performed with stress reduction protocol and sedation.

Moderate (absolute): Medical consultation recommended for any elective implant treatment.

Severe (absolute): Medical consultation recommended for any elective implant treatment.

Myocardial Infarction (MI)

image Do you have a history of myocardial infarction or heart attack? image/No?

Myocardial infarction (MI) is a prolonged ischemia or lack of oxygen resulting from a deficiency in coronary arterial blood supply that causes injury to the myocardium. The end result is cellular death and necrosis of the heart muscle. An acute MI may be precipitated when the patient undergoes unusual stress, either physical (painful stimuli) or emotional (anxiety). During an MI episode the patient usually will be symptomatic with severe chest pain in the substernal or left precordial area that may radiate to the left arm or mandible. Cyanosis, cold sweat, weakness, nausea or vomiting, and irregular and increased pulse rate are all signs and symptoms of MI.

Surgical/Implant Implications
Cardiovascular issues.

The intraoperative complications of past MI patients include arrhythmias and congestive heart failure (CHF). The larger the ischemic area, the greater the risk of heart failure or life-threatening arrhythmias. Any history of MI indicates damage to the coronary blood vessels. Therefore, recent infarctions correspond to higher morbidity and death rates, even with simple elective surgery. Approximately 18% to 20% of patients with a recent history of MI will have an increase in complications, which have a high mortality rate of 40% to 70%.16

Complication Prevention
Medical consultation.

A medical consultation should precede any extensive restorative or surgical procedure. Even though there are recommendations based solely on the length of time after an MI, the deciding factor on elective dental implant treatment is not only time but also the amount of myocardial damage. The implant clinician should follow the recommendation of the physician concerning treatment options, modifications, or contraindications.

Stress reduction protocol.

Dental implant surgery after MI may induce arrhythmias or aggravate cardiac ischemia. An increased blood pressure is not uncommon in the dental office setting because stress associated with treatment (i.e., white coat syndrome) leads to increased levels of catecholamine, which causes an increase in blood pressure and heart rate. The most important step in decreasing stress in the dental office is to integrate a comprehensive stress reduction protocol.

Reduction in the use of vasoconstrictors.

Epinephrine and other vasoconstrictors have several properties that can potentially result in adverse outcomes in patients that have not fully recovered from a recent myocardial infarction. Epinephrine is chronotropic, which results in an increased heart rate and force of contraction. Both of these result in an increased oxygen demand and could potentiate ischemia. Epinephrine does have some arrhythmogenic properties that could provoke ventricular fibrillation or tachycardia in recovering myocardial muscle. It is best to minimize complications by consulting the patient’s treating physician and closely monitoring vital signs when vasoconstrictors are used.

MI treatment summary.

The patient’s physician should be consulted prior to elective dental implant treatment to verify the patient’s current cardiac status.

Absolute (surgical): Recent MI (depending on MD recommendation)

Relative (surgical): History of MI (depending on MD recommendation)

Cerebrovascular Accident (CVA)

image Do you have a history of cerebrovascular accident (stroke)? image/No?

A stroke is a cerebrovascular accident (CVA) characterized by a sudden interruption of blood flow to the brain, causing oxygen deprivation. It is most frequently seen in patients with current cardiovascular diseases and is the fourth leading cause of death in the United States and a major cause of adult disability. The majority of strokes are ischemic resulting from narrowing or blocking of the blood supply to the brain. The etiology of ischemic strokes is embolic and thrombotic. Thrombotic strokes are the result of clots that form inside one of the brain’s arteries. The clot blocks blood flow to the brain causing cell death. Usually, these result from plaque or other fatty deposits from atherosclerosis, which break off and become lodged in the blood vessel. Embolic strokes are the results of clots that form in other parts of the body and travel to the brain via the bloodstream. The clot eventually will lodge in a blood vessel and block flow of blood to the brain. It is important to ask patients if they have ever been diagnosed or treated for ministrokes or TIAs (transient ischemic attacks). These attacks are the result of brief (usually less than 24 hours) interruptions in blood flow causing strokelike symptoms.

Surgical/Implant Implications
Bleeding.

Although it is important to control blood pressure and treat elevated cholesterol in the management of individuals with a history of strokes, caution should be taken because most are on blood-thinning medication. Antiplatelet agents such as aspirin or clopidogrel may be used as single agents or in combination as part of stroke prevention treatment. Both of these medications irreversibly impact platelets’ clotting ability and have been shown to cause increased bleeding. In some cases warfarin (Coumadin) may also be used, which directly interferes with the body’s clotting mechanisms. Evaluation and bleeding control are essential in these types of patients.

Limited dexterity.

Patients who have suffered a compromise in dexterity as the result of a stroke require alternative treatment planning for their final prostheses. A fixed prosthesis is usually the best solution for these patients because an implant retained prosthesis may lead to the inability to remove for routine hygiene. Additionally, poor oral hygiene when combined with xerostomia causes additional oral problems such as candidiasis, dental caries, periodontal issues, and mucositis lesions, which increase implant prostheses morbidity.

Complication Prevention
Current anticoagulant medications.

The goal of anticoagulation medication is to keep the blood thinned so clotting is more difficult. However, it is important to understand these medications work by various pathways and can impact clotting at different points in the clotting cascade or by directly inhibiting platelet function. The antiplatelet agents such as aspirin or clopidogrel have been shown to have a minimal impact on bleeding both intraoperative and postoperative.17 Several studies have found no increased risk of bleeding during dental procedures when patients on Coumadin are within the therapeutic treatment range of an international normalized ratio (INR) below 3.0. In patients with mechanical heart valves, the upper limit of the therapeutic range can reach 3.5 to 4.0. In patients with artificial valves, the INR may be checked 24 hours prior to the implant surgery. Under no circumstances should a patient with a mechanical valve on Coumadin be instructed to stop or hold a dose without input from the patient’s treating physician.

Hemostatic agents/surgical technique.

Ideal surgical technique should be followed which consists of nontraumatic incision and reflection of tissue. The surgical procedures should be minimized with a decreased surgical duration. The implant clinician must have experience with the use of active and passive hemostatic agents (see Chapter 7).

Treatment summary

Absolute (surgical): Recent CVA incident (MD Consult)

Relative (surgical): History of CVA + anticoagulants (MD Consult)

Congestive Heart Failure (CHF)

image Do you have a history of congestive heart failure? image/No?

Congestive heart failure (CHF) is a pathophysiologic state in which an abnormality in cardiac function is responsible for failure of the heart to pump blood in adequate volume to meet the needs of the metabolizing tissues. More than 3 million people in the United States suffer from CHF, with approximately 400,000 new patients being diagnosed each year. Every year 30% to 40% of patients with CHF are hospitalized, which accounts for the leading diagnosis-related group of hospitalized patients older than age 65.18

The heart pumps approximately 2000 gallons of blood per day to other organs and body tissues. It coordinates the function of two pumps simultaneously: the left side, the larger of the two sides, pushes the blood out into the body; the right side sends the blood to the lungs for oxygenation. When the heart has been damaged, the blood begins to back up in the lungs or body. The heart will attempt to compensate by increasing the rate of contraction and stretching the muscle to accommodate a larger volume of blood to contract with a greater force and eject more blood (Frank-Starling law). Both of these compensation attempts of the heart maintain circulatory needs in the short term; however, long term they may be problematic. Less blood is circulated because, in beating faster, the heart is left with less time to refill, while the extra effort increases the heart muscle’s demand for oxygen. When this need is not met, the heart rhythms can become dangerously abnormal (arrhythmic) and may lead to death.

Surgical/Implant Implications.

CHF patients are very susceptible to intraoperative cardiovascular morbidity issues. Stress reduction protocol and strict monitoring should be followed. It is advisable to discuss the current condition of the patient with their treating physician (Box 2.2). Patients with CHF can be classified as compensated or uncompensated. In uncompensated heart failure, the pulmonary circulation is expanded and congested because the heart is unable to fully compensate. The classic symptoms are seen including shortness of breath especially with exertion, fatigue, or lying supine. When the CHF patient is treated for heart failure through medical management and the symptoms are controlled, the patient is referred to as compensated.

 

Box 2.2

New York Heart Association Cardiac Disease Classification

NYHA I: (Relative) Patients that have no limitation of physical activity.

NYHA II: (Relative) Patients with cardiac disease that results in slight limitation to physical activity with symptoms such as fatigue, palpations, dyspnea, or angina pain.

NYHA III: (Absolute) Patients with cardiac disease who are comfortable at rest; however, less-than-ordinary activity causes fatigue, palpation, dyspnea, or angina pain.

NYHA IV: (Absolute) Patients with cardiac disease that results in the inability to carry on any physical activity.

Complication Prevention
Recognize CHF symptoms.

Although the treatment of CHF should be left up to the patient’s physician, it is important to realize that CHF can worsen without warning or slowly over time. It is important to evaluate the patient’s breathing at rest and with minimal exertion upon walking, as well as to determine if breathing has worsened when the patient is lying down. Changes in any of these patterns of breathing could indicate a decompensation of their congestive heart failure. Additionally, it is important to evaluate for neck swelling in the jugular area, which may indicate right-sided heart congestion.

Patient positioning.

CHF patients should be positioned in the most recumbent position in which they can breathe comfortably and efficiently. This is usually a semireclined or sitting upright position. Usually, the more upright the patient, the easier it is for the patient to breathe.

Oxygen supplementation.

Oxygen supplementation (≈2 L/min) during implant procedures is highly recommended to minimize the possibility of hypoxia. The use of nitrous oxide in these patients is not advised.

Stress reduction protocol.

Previously described to prevent increased myocardial workload with a damaged heart.

image Are you predisposed to infectious endocarditis? image/No?

The pathogenesis of infectious endocarditis is complex and associated with many factors. Vessel turbulence in the endothelium of cardiac vessel or pulmonary shunts combined with bacteremia (streptococci, staphylococci, enterococci) from oral surgical procedures may cause bacteria proliferation at the site resulting in infection. These bacteria may enter the bloodstream and can infect the heart valves. In time the bacteria can destroy heart valves resulting in life-threatening cardiac conditions. For this reason, antibiotic coverage is recommended in high-risk individuals undergoing procedures that may cause these types of bacteremia. The guidelines issued in 1997 for endocarditis antibiotic prophylaxis were very broad. In 2007 the guidelines were updated using recommendations from the American Heart Association Endocarditis Committee (Box 2.3 and Table 2.2).

 

Box 2.3

Endocarditis Prophylaxis Recommendation

The American Dental Association, American Medical Association, and the American Heart Association have recommended antibiotic coverage in patients with the following conditions receiving elective surgery.

Artificial heart valves

Past history of infectious endocarditis

Cardiac transplant that develops a heart valve problem

Congenital heart disease with shunts or conduitsa repaired

Congenital heart defect with residual defect

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Jan 12, 2018 | Posted by in Implantology | Comments Off on Medical/Medication Complications in Oral Implantology
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