Practice Guidelines
AHA Releases Updated Guidelines on the Prevention of Infective Endocarditis
Guideline source: American Heart Association
Literature search described? Yes
Evidence rating system used? Yes
Published source: Circulation, October 2007
Available at: http://circ.ahajournals.org/cgi/content/full/116/15/1736
See related editorial on page 421.
The American Heart Association (AHA) last published guidelines on the prevention of infective endocarditis in 1997. Since then, many studies have questioned the effectiveness of antibiotic prophylaxis for prevention of infective endocarditis in patients undergoing dental or gastrointestinal (GI) or genitourinary (GU) tract procedures. The AHA has revised its guidelines to reflect these new data.
Pathogenesis
Infective endocarditis is caused by interactions between the bloodstream pathogen with matrix molecules and platelets at sites of endocardial cell damage. It results from the following sequence of events: (1) formation of nonbacterial thrombotic endocarditis; (2) transient bacteremia; (3) adherence of the bacteria to nonbacterial thrombotic endocarditis; and (4) resulting bacterial proliferation.
Antibiotic Prophylaxis for Dental Procedures
It has been thought that dental procedures could cause infective endocarditis in patients with underlying cardiac risk factors, and that antibiotic prophylaxis is effective in preventing it; however, evidence for this theory is lacking. Published evidence indicates that a small number of cases of infective endocarditis are caused by dental procedures and, therefore, few patients would benefit from antibiotic prophylaxis, even if the antibiotics were 100 percent effective.
Most cases of infective endocarditis are caused by oral microflora that are probably the result of random bacteremia from routine daily activities (e.g., teeth brushing, flossing, chewing). Therefore, more emphasis should be placed on improving oral health and access to dental care in patients with underlying cardiac conditions that are associated with the highest risk of adverse outcomes and in those who have conditions that predispose them to infective endocarditis.
Cardiac Conditions and Infective Endocarditis
Previous AHA guidelines grouped underlying cardiac conditions associated with the risk of infective endocarditis by high, moderate, and negligible risk; antibiotic prophylaxis was recommended for patients in the high- and moderate-risk groups. When updating these guidelines, the AHA considered three criteria: (1) which underlying conditions have the highest predisposition for infective endocarditis; (2) which underlying conditions have the highest risk of adverse effects from infective endocarditis; and (3) whether recommendations for prophylaxis should be based on one or both of those groups of conditions.
CONDITIONS WITH HIGH PREDISPOSITION FOR INFECTIVE ENDOCARDITIS
Persons with rheumatic heart disease, mitral valve prolapse, and congenital heart disease have an increased lifetime risk of infective endocarditis compared with persons who have no known underlying cardiac conditions.
CONDITIONS WITH HIGHEST RISK OF ADVERSE EFFECTS FROM INFECTIVE ENDOCARDITIS
Infective endocarditis is serious and life threatening, regardless of the underlying cardiac condition. Several comorbid factors (e.g., older age, diabetes, immunosuppressive conditions) can cause complications. There also are long-term consequences of infective endocarditis. For example, a cardiac valve damaged by infective endocarditis can undergo progressive functional deterioration that could result in the need for cardiac valve replacement.
In native valve viridans group streptoccocal or enterococcal infective endocarditis, disease can range from a relatively benign infection to severe valvular dysfunction, dehiscence, congestive heart failure, multiple embolic events, and death. However, the conditions listed in Table 1 almost always have an increased risk of adverse outcomes. Patients with relapsing or recurrent infective endocarditis have a greater risk of congestive heart failure, as well as an increased need for cardiac valve replacement. They also have a higher mortality rate compared with patients who have not had infective endocarditis. Patients with multiple episodes of native or prosthetic-valve infective endocarditis have a greater risk of recurrent disease, with each subsequent episode being associated with a higher risk of serious complications.
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Table 1. Cardiac Conditions for Which Prophylaxis with Dental Procedures is Recommended |
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Cardiac valvulopathy in a cardiac transplant recipient Congenital heart disease* Congenital heart defect completely repaired within the previous six months with prosthetic material or device, whether placed by surgery or by catheter† Repaired congenital heart disease with residual defects at the site or adjacent to the site of a prosthetic patch or device (which inhibit endothelialization) Unrepaired cyanotic congenital heart disease, including palliative shunts and conduits Previous infective endocarditis Prosthetic cardiac valve |
| *-Except for the conditions listed, antibiotic prophylaxis is no longer recommended for patients with any other form of congenital heart disease. †-Prophylaxis is recommended because endothelialization of prosthetic material occurs within six months after the procedure. Adapted with permission from Wilson W, Taubert KA, Gewitz M, et al.; for the American Heart Association Rheumatic Fever, Endocarditis and Kawasaki Disease Committee; Council on Cardiovascular Disease in the Young; Council on Clinical Cardiology; the Council on Cardiovascular Surgery and Anesthesia; and the Quality of Care and Outcomes Research Interdisciplinary Working Group. Prevention of infective endocarditis [published correction appears in Circulation. 2007;116(15):e376-377]. Circulation. 2007;116(15):1745. |
Most retrospective studies suggest that patients with complex cyanotic heart disease, as well as those with postoperative palliative shunts, conduits, or other prostheses, have a high lifetime risk of infective endocarditis. They also seem to be at highest risk of morbidity and mortality. The AHA recommends antibiotic prophylaxis for dental procedures in these patients during the first six months after the procedure. The AHA does not recommend prophylaxis after six months following a dental procedure if there is no residual defect.
ANTIBIOTIC PROPHYLAXIS
The AHA no longer recommends antibiotic prophylaxis based on an increased lifetime risk of infective endocarditis. No data prove that antibiotic prophylaxis prevents bacteremia-associated infective endocarditis that occurs after an invasive procedure. If antibiotic prophylaxis is effective, it should be given only to patients with the highest risk of adverse outcomes from infective endocarditis. Prophylaxis for dental procedures could be beneficial in patients with underlying high-risk cardiac conditions; however, the AHA recognizes that effectiveness of this therapy is unknown.
Recommended Antibiotic Regimens
GENERAL
Antibiotic prophylaxis should be given in one dose before the procedure. If the dose is not given before the procedure, it can be given up to two hours afterward; however, postoperative administration of antibiotics should be considered only if the dose before the procedure is inadvertently missed.
If the patient has a fever or other signs of systemic infection that could be the result of infective endocarditis, the physician should obtain blood cultures or other laboratory tests before administering antibiotics. Failure to do so could result in a delayed diagnosis or treatment of concomitant infective endocarditis.
DENTAL PROCEDURES
Data show that transient viridans group streptococcal bacteremia can result from dental procedures that include manipulation of the gingival or periapical region of teeth or perforation of the oral mucosa. The likelihood of bacteremia is not automatically reduced if a procedure is minimally invasive or if the patient's mouth appears healthy. For these reasons, the AHA recommends that antibiotic prophylaxis be used in patients with the conditions listed in Table 1 and in those undergoing any dental procedure that manipulates the gingival or periapical region of teeth or that perforates the oral mucosa. However, the AHA recognizes that effectiveness of antibiotic prophylaxis in this situation is unknown.
Amoxicillin is the first-line agent for oral antibiotic therapy (Table 2) because it is absorbed well in the GI tract and provides high serum concentrations. For patients who are allergic to penicillin or amoxicillin, cephalexin (Keflex) or another first-generation cephalosporin, clindamycin (Cleocin), azithromycin (Zithromax), or clarithromycin (Biaxin) can be used. No data show that one oral cephalosporin is superior to another in the prevention of infective endocarditis. Generic cephalexin is widely available and relatively inexpensive.
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Table 2. Antibiotic Regimens for Patients at High Risk of Infective Endocarditis Undergoing Dental Procedures |
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Route of administration |
Agent |
Dosage |
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|
Adults |
Children |
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|
IM or IV |
Ampicillin or cefazolin (Ancef, brand not available in the United States) or ceftriaxone (Rocephin) |
2 g IM or IV |
50 mg per kg IM or IV |
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1 g IM or IV |
50 mg per kg IM or IV |
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IV or IM (in patients allergic to penicillin or ampicillin) |
Cefazolin or ceftriaxone* or clindamycin (Cleocin) |
1 g IM or IV |
50 mg per kg IM or IV |
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600 mg IM or IV |
20 mg per kg IM or IV |
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|
Oral |
Amoxicillin |
2 g |
50 mg per kg |
|
Oral (in patients allergic to penicillin or ampicillin) |
Cephalexin (Keflex)*† or clindamycin or azithromycin (Zithromax) or clarithromycin (Biaxin) |
2 g |
50 mg per kg |
|
600 mg |
20 mg per kg |
||
|
500 mg |
15 mg per kg |
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| IM = intramuscularly; IV = intravenously. *-Cephalosporins should not be used in patients with a history of anaphylaxis, angioedema, or urticaria after taking penicillin or ampicillin. †-Or other first- or second-generation oral cephalosporin in equivalent adult or pediatric dosage. Adapted with permission from Wilson W, Taubert KA, Gewitz M, et al.; for the American Heart Association Rheumatic Fever, Endocarditis and Kawasaki Disease Committee; Council on Cardiovascular Disease in the Young; Council on Clinical Cardiology; the Council on Cardiovascular Surgery and Anesthesia; and the Quality of Care and Outcomes Research Interdisciplinary Working Group. Prevention of infective endocarditis [published correction appears in Circulation. 2007;116(15):e376-377]. Circulation. 2007;116(15):1747. |
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RESPIRATORY TRACT PROCEDURES
Respiratory tract procedures have been reported to cause transient bacteremia with a wide range of microorganisms, but no data confirm a link between these procedures and risk of infective endocarditis. Antibiotic prophylaxis, as listed in Table 2, can be considered for patients with conditions listed in Table 1 who are undergoing an invasive respiratory tract procedure that includes a biopsy or incision of the respiratory mucosa (e.g., tonsillectomy, adenoidectomy). The AHA recommends antibiotic prophylaxis against viridans group streptococci for patients with conditions listed in Table 1 who are undergoing respiratory tract procedures to manage an established infection. If the infection is caused by Staphylococcus aureus, the patient should be given an antibiotic that is active against S. aureus (e.g., cephalosporins). Vancomycin (Vancocin) can be used in patients who cannot tolerate a beta lactam antibiotic or who have an infection caused by methicillin-resistant S. aureus.
GI OR GU TRACT PROCEDURES
Antibiotic prophylaxis is not recommended to prevent infective endocarditis in patients undergoing GI or GU tract procedures (e.g., diagnostic esophagogastroduodenoscopy, colonoscopy). Patients with GI or GU tract infections can have intermittent or sustained enterococcal bacteremia. For patients who have conditions listed in Table 1 and who also have established GI or GU tract infections, and for those who are taking antibiotics for a wound infection or sepsis associated with a GI or GU tract procedure, it may be beneficial to use antibiotic prophylaxis that is active against enterococci (e.g., penicillin, ampicillin, piperacillin, vancomycin). However, there is no evidence that this type of prophylaxis will prevent enterococcal infective endocarditis.
Antibiotic prophylaxis may be beneficial for eliminating enterococci in urine in patients with a condition listed in Table 1 who are undergoing an elective cystoscopy or other urinary tract procedure and who have an enterococcal urinary tract infection or colonization. If the procedure is not elective, the antibiotics should be active against enterococci.
Amoxicillin or ampicillin is the preferred agent for enterococcal coverage. If the patient cannot tolerate ampicillin, vancomycin can be used. Consultation with an infectious disease expert is recommended if the infection is caused by resistant enterococci.
PROCEDURES ON INFECTED SKIN, SKIN STRUCTURE, OR MUSCULOSKELETAL TISSUE
Infections of the skin, skin structure, or musculoskeletal tissue are typically polymicrobial, but only those caused by staphylococci and β-hemolytic streptococci are likely to cause infective endocarditis. Patients with conditions listed in Table 1 who undergo surgical procedures involving skin, skin structure, or musculoskeletal tissue can be given a therapeutic regimen that contains agents active against staphylococci and β-hemolytic streptococci (e.g., penicillin, cephalosporins). Vancomycin or clindamycin can be used in patients unable to tolerate beta lactam antibiotics and in those with infections caused by methicillin-resistant staphylococcus.
Specific Situations and Circumstances
PATIENTS ALREADY TAKING ANTIBIOTICS
If a patient is on a long-term antibiotic regimen with an antibiotic that is also recommended for infective endocarditis prophylaxis for a dental procedure, the patient should be given an antibiotic from a different class rather than simply increasing the dosage of the current antibiotic. Cephalosporins should be avoided because of possible cross-resistance of viridans group streptococci. If possible, dental procedures should be delayed at least 10 days after completion of the antibiotic regimen so that there is enough time for the usual flora to be reestablished.
Patients who are taking parenteral antibiotics for infective endocarditis may need to have a dental procedure during therapy, particularly if the patient is planning to have cardiac valve replacement surgery. In these circumstances, parenteral antibiotics should be continued and dosage timing adjusted so that the drug is taken 30 to 60 minutes before the dental procedure.
PATIENTS TAKING ANTICOAGULANTS
Intramuscular injections for infective endocarditis prophylaxis should not be given to patients taking anticoagulants. Oral antibiotics should be given instead, if possible.
PATIENTS UNDERGOING CARDIAC SURGERY
A dental examination before cardiac surgery is recommended so that dental treatment can be completed before the procedure. Patients who undergo surgery for prosthetic heart valves or intravascular or intracardiac materials are at risk of infection. Because morbidity and mortality associated with these infections are high, perioperative antibiotic prophylaxis is recommended.
Early-onset prosthetic valve endocarditis is most often caused by S. aureus, coagulase-negative staphylococci, or diphtheroids. No antibiotic regimen is effective against all of these microorganisms. Antibiotic prophylaxis at the time of surgery should be against staphylococci and should be of short duration. A first-generation cephalosporin is typically used; however, antibiotic choice should take into account the antibiotic susceptibility patterns of the patient's hospital. Most nosocomial coagulase-negative staphylococci are methicillin resistant. Even so, antibiotic prophylaxis with a first-generation cephalosporin is recommended for these patients.
In hospitals with a high prevalence of methicillin-resistant strains of Staphylococcus epidermidis, antibiotic prophylaxis with vancomycin may be beneficial, but has not been found superior to cephalosporins. Prophylaxis should be started immediately before the operation, repeated during prolonged operations (to maintain serum concentrations), and continued for up to 48 hours after the operation (to minimize resistant microorganisms).
Other Considerations
Because coronary artery bypass graft surgery is not associated with a long-term risk of infection, antibiotic prophylaxis for dental procedures is not needed in persons who have undergone such surgeries. Antibiotic prophylaxis also is not recommended for persons with coronary artery stents who undergo a dental procedure.
Although patients who have had a heart transplant are at risk of acquired valvular dysfunction, there is insufficient evidence to support specific recommendations for this population. Infective endocarditis that occurs in these patients is associated with a high risk of adverse outcomes; therefore, antibiotic prophylaxis in patients who have had a heart transplant and who undergo dental procedures may be beneficial, but its usefulness is not well established.
A summary of the major changes in these updated recommendations for prevention of infective endocarditis compared with previous AHA guidelines is shown in Table 3.
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Table 3. Summary of Major Changes in the Updated AHA Guidelines for Prevention of Infective Endocarditis |
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Antibiotic prophylaxis is no longer recommended for patients with any form of congenital heart disease except those listed in Table 1 Antibiotic prophylaxis is not recommended based solely on an increased lifetime risk of infective endocarditis Antibiotic prophylaxis is recommended only for patients with conditions listed in Table 1 who are undergoing dental procedures that involve manipulation of gingival tissues or periapical region of teeth, or perforation of the oral mucosa Antibiotic prophylaxis is recommended only for patients with conditions listed in Table 1 who are undergoing procedures on the respiratory tract or infected skin, skin structures, or musculoskeletal tissue Antibiotic prophylaxis solely to prevent infective endocarditis is not recommended for patients undergoing gastrointestinal or genitourinary tract procedures Prophylaxis for infective endocarditis is not recommended in patients undergoing ear or body piercing, tattooing, vaginal delivery, or hysterectomy Recommendations for prophylaxis of infective endocarditis should be limited to patients with conditions listed in Table 1 |
| AHA = American Heart Association. Adapted with permission from Wilson W, Taubert KA, Gewitz M, et al.; for the American Heart Association Rheumatic Fever, Endocarditis and Kawasaki Disease Committee; Council on Cardiovascular Disease in the Young; Council on Clinical Cardiology; the Council on Cardiovascular Surgery and Anesthesia; and the Quality of Care and Outcomes Research Interdisciplinary Working Group. Prevention of infective endocarditis [published correction appears in Circulation. 2007;116(15):e376-377]. Circulation. 2007;116(15):1748. |
ACOG Guidelines on Endometrial Ablation
Guideline source: American College of Obstetricians and Gynecologists
Literature search described? Yes
Evidence rating system used? Yes
Published source: Obstetrics & Gynecology, May 2007
Available at: http://www.greenjournal.org/cgi/reprint/109/5/1233 (subscription required)
Endometrial ablation refers to minimally invasive surgical procedures that treat abnormal uterine bleeding in select women who have no desire for fertility. In its guidelines for endometrial ablation, the American College of Obstetricians and Gynecologists (ACOG) compare standard resectoscopic endometrial ablation with nonresectoscopic endometrial ablation techniques and devices. ACOG also reviewed the indications, effectiveness, safety, and limitations of endometrial ablation.
Indications
Endometrial ablation should be used to treat premenopausal women with normal endometrial cavities who have menorrhagia or patient-perceived heavy menstrual bleeding. These should be women who have no desire for future fertility, and they most likely will have been unsuccessful with or are intolerant of medical therapy. Although failure or intolerance of medical therapy and anemia are important considerations, they are not prerequisites for the procedure.
When excessive bleeding or menorrhagia occurs in the context of submucosal myomata, endometrial ablation may be effective. However, this depends on the diameter and location of the myomata as well as the system used for the procedure.
Physicians should advise patients who choose endometrial ablation that the normalization of menstrual blood flow-not necessarily amenorrhea-may be the outcome of the procedure. In addition, ACOG recommends that physicians counsel premenopausal women who are undergoing endometrial ablation to use appropriate contraception.
Evaluation
Physicians should thoroughly evaluate the histology and structure of the endometrial cavity to assess evidence of endometrial hyperplasia or malignancy. They must also ensure that the configuration and length are suitable for endometrial ablation. Women with uterine cancer or endometrial hyperplasia should not undergo endometrial ablation.
Endometrial sampling should be performed to evaluate all women for malignancy or hyperplasia. Transvaginal ultrasonography, hysteroscopy, saline infusion sonohysterography, or a combination of these procedures should be performed to measure the length of the cavity and detect any structural abnormalities or submucosal and intracavitary myomata. If such myomata are identified, physicians should determine the diameter and proportion of the lesion or lesions that extend into the endometrial cavity.
Adverse Events
Resectoscopic endometrial ablation and nonresectoscopic endometrial ablation have been associated with a number of adverse events, including urinary tract infection, vaginal infection, fever, and endometriosis. Adverse events related to fluid overload and electrolyte disturbances are unique to resectoscopic endometrial ablation. However, both approaches have been associated with injury to the vagina or cervix, bleeding, and uterine perforation with the potential to damage surrounding structures.
Summary of Recommendations
The following recommendations are based on good and consistent scientific evidence:
• For women with normal endometrial cavities, nonresectoscopic endometrial ablation and resectoscopic endometrial ablation may be equally successful in the reduction of menstrual flow and in patient satisfaction after one year.
• Resectoscopic endometrial ablation is associated with high patient satisfaction; however, patient satisfaction is even higher with hysterectomy.
The following recommendations are based on limited or inconsistent scientific evidence:
• Hysterectomy rates associated with resectoscopic and nonresectoscopic endometrial ablation are 24 percent or more within four years after the procedure.
• Women with previous or concomitant laparoscopic sterilization who undergo endometrial ablation are at low risk of developing intermittent or cyclic pelvic pain after the procedure.
• Women with normal endometrial cavities have similar patient satisfaction and reduction in menstrual blood flow after endometrial ablation as women who use the levonorgestrel-releasing intrauterine system (Mirena).
The following recommendations are based primarily on consensus and expert opinion:
• Physicians should advise patients who choose endometrial ablation that normalization of menstrual blood flow may be the outcome of the procedure.
• Physicians should counsel premenopausal patients undergoing endometrial ablation to use appropriate contraception.
• Nonresectoscopic endometrial ablation is not recommended in women who have endometrial cavities that exceed device limitations.
• Physicians should test the endometrium of all candidates for endometrial ablation. Physicians also should review the histopathologic results before the procedure.
• Women with uterine cancer or endometrial hyperplasia should not undergo endometrial ablation.
• Performing nonresectoscopic endometrial ablation on patients who have had transmural myomectomy or classic cesarean delivery may increase the risk of damage to surrounding structures. If endometrial ablation is required in these patients, physicians should perform resectoscopic endometrial ablation with laparoscopic monitoring.
• A fluid management and monitoring system that provides "real time" output of fluid balance should be used during resectoscopic endometrial ablation.
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