cardiovascular disorders
Infective Endocarditis
Treatment of Infective Endocarditis
IV antibiotics (based on the organism and its susceptibility) Sometimes valve debridement, repair, or replacement Dental evaluation and treatment (to minimize oral sources of bacteremia) Removal of potential source of bacteremia (eg, internal catheters, devices) Withholding anticoagulation in patients with cerebral embolism Treatment consists of a prolonged course of antimicrobial therapy ( Treatment references ). Surgery may be needed for mechanical complications or resistant organisms. Typically, antimicrobials are given IV. Because they must be given for 2 to 8 weeks, home IV therapy is often used. Any apparent source of bacteremia must be managed: necrotic tissue debrided, abscesses drained, and foreign material and infected devices removed. People with infective endocarditis should be evaluated by a dentist and treated for oral diseases that could cause bacteremia and subsequent endocarditis. Existing IV catheters (particularly central venous ones) should be changed. If endocarditis persists in a patient with a newly inserted central venous catheter, that catheter should also be removed. Organisms within biofilms adherent to catheters and other devices may not respond to antimicrobial therapy, leading to treatment failure or relapse. If continuous infusions are used instead of intermittent boluses, infusions should not be interrupted for long periods. Drugs and dosages depend on the microorganism and its antimicrobial susceptibility. (For typical regimens, see table Some Antibiotic Regimens for Endocarditis in the United States .) Although most patients are stable enough to wait for culture results, empiric antibiotic therapy before organism identification may be necessary in seriously ill patients.Antibiotics should not be given until adequate blood cultures (minimally, generally 2 or 3 samples from different sites over 1 hour) have been obtained.Antibiotics should be broad spectrum to cover all likely organisms, typically including sensitive and resistant staphylococci, streptococci, and enterococci. Empiric antibiotic regimens should reflect local patterns of infection and antibiotic resistance; however, typical examples of broad-spectrum antibiotic coverage may include Native valves:Vancomycin15 to 20 mg/kg IV every 8 to 12 hours (not to exceed 2 g per dose) Prosthetic valve:Vancomycin15 to 20 mg/kg IV every 8 to 12 hours (not to exceed 2 g per dose) plusgentamicin1 mg/kg IV every 8 hours plus eithercefepime2 g IV every 8 hours or imipenem 1 g IV every 6 to 8 hours (maximum dose 4 g per day) As soon as possible, the empiric drug regimen should be adjusted based on culture results. Patients who use IV illicit drugs frequently do not adhere to treatment, use IV access lines inappropriately, and tend to leave the hospital too soon. For such patients, short-course IV or (less preferably) oral therapy may be used. For right-sided endocarditis caused by methicillin-sensitiveS. aureus,nafcillin2 g IV every 4 hours plusgentamicin1 mg/kg IV every 8 hours for 2 weeks is effective, as is a 4-week oral regimen ofciprofloxacin750 mg twice a day plusrifampin300 mg twice a day. Left-sided endocarditis does not respond to 2-week courses. For left-sided endocarditis, current guidelines recommend 6 weeks of parenteral antibiotic therapy. However, a recent multicenter, randomized, non-blinded study of uncomplicated left-sided endocarditis found that switching to oral antibiotics (after a minimum of 10 days of parenteral therapy) to be non-inferior to continued parenteral therapy. In addition, length of hospital stay was shortened in the patients switched to oral therapy. This approach has the potential to reduce the psychologic stress and some of the risks inherent to prolonged inpatient parenteral therapy ( Treatment references ). Surgery (debridement, valve repair, or valve replacement) is sometimes required for treatment of infectious endocarditis ( Treatment references ). Surgery is typically indicated in Patients with heart failure (particularly those with prosthetic, aortic, or native mitral valve endocarditis and those with pulmonary edema or cardiogenic shock) Patients with uncontrolled infection (those with persistent infection, infection with fungal or resistant organisms, recurrent prosthetic valve endocarditis, or endocarditis complicated by heart block, abscess, aneurysm, fistula, or enlarging vegetation) Patients at risk for embolism (particularly those with prosthetic, aortic or mitral native valve endocarditis, and large vegetations [defined in the United States as > 10 mm] or those with recurrent emboli). Early surgery in these patients decreases the risk of embolic events. Timing of surgery requires experienced clinical judgment. If heart failure caused by a correctable lesion is worsening (particularly when the organism isS. aureus, a gram-negative bacillus, or a fungus), surgery may be required after only 24 to 72 hours of antimicrobial therapy. Endocarditis involving an implanted cardiac electronic device requires complete removal of the pacemaker or defibrillator, including all leads and the generator. Right-sided endocarditisis usually managed medically. If surgery is necessary (due to heart failure or lack of therapeutic response), then valve repair is preferred over replacement to avoid future prosthetic valve infection due to any continued IV drug use. Surgery is usually delayed for a month after intracranial hemorrhage or major ischemic stroke. Patients taking anticoagulants are at increased risk for hemorrhagic stroke and for bleeding resulting from urgent invasive procedures. Anticoagulation should be withheld in patients with cerebral emboli, because it increases the risk of hemorrhagic transformation. The decision to withhold anticoagulation in other patients should be based on the relative risks of hemorrhagic stroke and thromboembolism ( Treatment references ). After starting therapy, patients with penicillin-susceptible streptococcal endocarditis usually feel better, and fever is reduced within 3 to 7 days. Fever may continue for reasons other than persistent infection (eg, drug allergy, phlebitis, infarction due to emboli). Patients with staphylococcal endocarditis tend to respond more slowly. Diminution of vegetation size can be followed by serial echocardiography. Echocardiography should be done at the completion of therapy to establish a new baseline for valvular appearance (including sterile vegetations) and insufficiency. Relapse usually occurs within 4 weeks. Antibiotic retreatment may be effective, but surgery may also be required. In patients without prosthetic valves, recrudescence of endocarditis after 6 weeks usually results from a new infection rather than a relapse. Even after successful antimicrobial therapy, sterile emboli and valve rupture may occur up to 1 year later. Risk of recurrence is significant, so ongoing life-long dental and cutaneous hygiene is advised. Patients who require antibiotic therapy for any reason should have at least 3 sets of blood cultures drawn before antibiotics are started. 1.Baddour LM, Wilson WR, Bayer AS, et al: Infective endocarditis in adults: Diagnosis, antimicrobial therapy, and management of complications: A scientific statement for healthcare professionals from the American Heart Association.Circulation132:1435–1486, 2015. 2.Iversen K, Ihlemann N, Gill SU, et al: Partial oral versus intravenous antibiotic treatment of endocarditis.N Engl J Med380:415–424, 2019. DOI: 10.1056/NEJMoa1808312 3.Cahill TJ, Baddour LM, Habib G, et al: Challenges in infective endocarditis.J Am Coll Cardiol69(3):325–344, 2017. 4.Otto CM, Nishimura RA, Bonow RO, et al: 2020 ACC/AHA Guideline for the management of patients with valvular heart disease: A report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines.J Am Coll Cardiol77(4):e25–e197, 2021. doi: 10.1016/j.jacc.2020.11.018 