Chapter 118. Infective Endocarditis (Part 13)

Timing of Cardiac Surgery In general, when indications for surgical treatment of infective endocarditis are identified, surgery should not be delayed simply to permit additional antibiotic therapy, since this course of action increases the risk of death (Table 118-6). Delay is justified only when infection is controlled and congestive heart failure is fully compensated with medical therapy. After 14 days of recommended antibiotic therapy, excised valves are culture-negative in 99% and 50% of patients with streptococcal and S. aureus endocarditis, respectively. Recrudescent endocarditis involving a new implanted prosthetic valve follows surgery in 2% of patients with culture-positive native valve...
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Chapter 118. Infective Endocarditis (Part 13) Chapter 118. Infective Endocarditis (Part 13) Timing of Cardiac Surgery In general, when indications for surgical treatment of infective endocarditisare identified, surgery should not be delayed simply to permit additional antibiotictherapy, since this course of action increases the risk of death (Table 118-6). Delayis justified only when infection is controlled and congestive heart failure is fullycompensated with medical therapy. After 14 days of recommended antibiotictherapy, excised valves are culture-negative in 99% and 50% of patients withstreptococcal and S. aureus endocarditis, respectively. Recrudescent endocarditisinvolving a new implanted prosthetic valve follows surgery in 2% of patients withculture-positive native valve endocarditis and in 6–15% of patients with activeprosthetic valve endocarditis. These risks are more acceptable than the highmortality rates that result when surgery is inappropriately delayed or notperformed. Among patients who have experienced a neurologic complication ofendocarditis, further neurologic deterioration can occur as a consequence ofcardiac surgery. The risk of significant neurologic exacerbation is related to theinterval between the complication and the surgery. Whenever feasible, cardiacsurgery should be delayed for 2–3 weeks after a nonhemorrhagic embolic strokeand for 4 weeks after a hemorrhagic embolic stroke. A ruptured mycotic aneurysmshould be clipped and cerebral edema allowed to resolve before cardiac surgery. Antibiotic Therapy after Cardiac Surgery Bacteria visible in Gram-stained preparations of excised valves do notnecessarily indicate a failure of antibiotic therapy. Organisms have been detectedon Grams stain—or their DNA has been detected by PCR—in excised valvesfrom 45% of patients who have successfully completed the recommended therapyfor endocarditis. In only 7% of these patients are the organisms, most of which areunusual and antibiotic resistant, cultured from the valve. Despite the detection oforganisms or their DNA, relapse of endocarditis after surgery is uncommon. Thus,for uncomplicated native valve infection caused by susceptible organisms inconjunction with negative valve cultures, the duration of preoperative pluspostoperative treatment should equal the total duration of recommended therapy,with ~2 weeks of treatment administered after surgery. For endocarditiscomplicated by paravalvular abscess, partially treated prosthetic valve infection, orcases with culture-positive valves, a full course of therapy should be givenpostoperatively. Extracardiac Complications Splenic abscess develops in 3–5% of patients with endocarditis. Effectivetherapy requires either image-guided percutaneous drainage or splenectomy.Mycotic aneurysms occur in 2–15% of endocarditis patients; half of these casesinvolve the cerebral arteries and present as headaches, focal neurologic symptoms,or hemorrhage. Cerebral aneurysms should be monitored by angiography. Somewill resolve with effective antimicrobial therapy, but those that persist, enlarge, orleak should be treated surgically if possible. Extracerebral aneurysms present aslocal pain, a mass, local ischemia, or bleeding; these aneurysms are treated byresection. Outcome Older age, severe comorbid conditions, delayed diagnosis, involvement ofprosthetic valves or the aortic valve, an invasive (S. aureus) or antibiotic-resistant(P. aeruginosa, yeast) pathogen, intracardiac complications, and major neurologiccomplications adversely impact outcome. Death and poor outcome often arerelated not to failure of antibiotic therapy but rather to the interactions ofcomorbidities and endocarditis-related end-organ complications. Overall survivalrates for patients with native valve endocarditis caused by viridans streptococci,HACEK organisms, or enterococci (susceptible to synergistic therapy) are 85–90%. For S. aureus native valve endocarditis in patients who do not inject drugs,survival rates are 55–70%, whereas 85–90% of injection drug users survive thisinfection. Prosthetic valve endocarditis beginning within 2 months of valvereplacement results in mortality rates of 40–50%, whereas rates are only 10–20%in later-onset cases. Prevention Antibiotic prophylaxis has been recommended by the American HeartAssociation in conjunction with selected procedures considered to entail a risk forbacteremia and endocarditis. The benefits of prophylaxis, however, are notestablished and in fact may be modest: only 50% of patients presenting with nativevalve endocarditis know that they have a predisposing valve lesion, mostendocarditis cases do not follow a procedure, and 35% of cases are caused byorganisms not tar ...