Certain echocardiographic findings are recognized as being predictive of the need for
surgery in IE (197). Among these are: (i) detectable vegetations following a large embolus, (ii)
anterior mitral valve vegetations that are greater than 1 cm in diameter, (iii) continued growth
vegetations after four weeks of antibiotic therapy, (iv) development of acute mitral
insufficiency, (v) rupture or perforation of a valve, and (vi) periannular extension of the
valvular infection (198).
The need for and timing of surgery may be divided into three stages. stage 1—the post
antibiotic state— surgery that is required for severe aortic regurgitation that begins after
bacteriological cure of IE has been achieved; stage 2—elective—surgery during antimicrobial
therapy in patients who develop cardiac failure that responds rapidly to medical management;
and stage 3—emergent—surgery in patients who suffer from severe complications such as
intractable congestive heart failure or persistent BSI (199).
It is extremely important to rule out splenic abscess before surgery is performed for
“refractory IE.” These are often clinically occult and produce a continuous BSI (200).
Surgery is often required to eradicate a variety of metastatic infections including
aneurysm and cerebral abscesses.
Debridement and the administration of antibiotics may cure an uncomplicated
pacemaker infection. Treatment of PMIE requires that the entire system be removed. If the
leads have been in place for more than 18 months, their extraction may be extremely difficult.
Excimer laser sheaths, by dissolving the fibrotic bands that encase the electrodes, are able to
produce complete removal in more than 90% of cases (201).
An increasingly common problem in the CCU in the management ofS. aureusBSI is the
presence of an intravascular catheter. Greater than 25% of these bacteremias represent valvular
infection. Correctly differentiating those cases of uncomplicated staphylococcal BSI from
endocarditis is essential not only for determining the length of antibiotic therapy but also
whether long-term intravascular catheters need to be removed at all. Short-term catheters
always need to be removed in the setting ofS. aureusBSI. When associated withS. aureus
bacteruria, hematuria may be an indicator of sustainedS. aureusbacteremia. This type of
hematuria may result from either embolic renal infarction or immunologically mediated
glomerulonephritis (202). The presence of intracellular bacteria on blood smears that are
obtained through intravascular catheters is specific for infection of these devices (203). TEE is
the most specific approach of separating a continuous, uncomplicatedS. aureusbacteremia
from IE. At least 23% CRBSI, caused byS. aureus, have substantial evidence of valvular
infection even in the absence of clinical findings and a negative TTE. Table 13 (204) presents an
approach to management of short-term intravascular catheter associatedS. aureuscontinuous
BSI. It is always essential that infected, short-term intravascular catheters be removed. Cure
rates are as low as 20% with antibiotic therapy alone without prompt removal of the catheters
(205). Surgically implanted long-term catheters (Broviac, Hickman) do need to be
Table 13 Management ofS. aureusBacteremia in the Presence of an Intravascular Catheter
- Prompt removal of the catheter
- Institution of appropriate antibiotic therapy
- Follow-up blood cultures within 24–48 hr
A. If follow-up blood cultures are negative and:- The TEE shows no signs of infective endocarditis.
- There is no evidence of metastatic infection.
Then 2 wk of antibiotic therapy would be appropriate
B. If follow-up blood cultures are positive and:
- The TEE shows signs of infective endocarditis.
Then 4 wk of intravenous therapy is appropriate
C. If follow-up blood cultures are positive and: - The TEE shows no signs of infective endocarditis.
Further imaging studies should be performed to rule out other sources of bacteremia (osteomyelitis,
mediastinitis, splenic abscess)
Infective Endocarditis and Its Mimics in Critical Care 239