Infective Endocarditis

ROLE OF VALVE SURGERY

In patients with IE treated with antibiotic therapy, a number of complications are associated with poor prognosis and may warrant early surgical therapy (ie, surgery performed prior to completion of antimicrobial therapy).

When early surgery is indicated, it should not be delayed except for patients with major cerebrovascular complications (eg, hemorrhagic stroke) or those with high operative risk or poor long-term prognosis due to other medical problems. Patients who experience embolic events in the central nervous system without hemorrhage or major neurologic impairment may still undergo cardiac surgery with reasonable risk, but surgical delay for at least four weeks is appropriate for patients with hemorrhagic stroke.

For native valve IE

For left-sided native valve IE — Patients with left-sided native valve endocarditis (NVE) frequently require early valve surgery due to the presence of one or more complications (eg, IE-associated valve dysfunction complicated by HF, intracardiac abscess, difficult-to-treat pathogen, and/or persistent infection) [8]. Indications for surgery for left-sided NVE are discussed separately. (see "Surgery for left-sided native valve infective endocarditis")

For right-sided native valve IE — Indications for surgery in right-sided NVE include very large vegetations (≥20 mm in diameter), recurrent septic pulmonary emboli, highly resistant organisms, or persistent bacteremia [4]. HF is not a common indication for early surgery in right-sided NVE, since severe tricuspid valve regurgitation is better tolerated (from a hemodynamic standpoint) than severe left-sided regurgitation. Severe tricuspid regurgitation causing right HF that is poorly responsive to medical therapy is a less common indication for surgery [4,9]. In such cases, valve repair is generally preferred to valve replacement, particularly in PWID [4,10]. (See "Right-sided native valve infective endocarditis", section on 'Management'.)

For people who inject drugs — The indications for surgery in patients with IE and concurrent injection drug use are generally the same as for other patients with IE. IE in PWID most commonly affects the tricuspid valve, but can involve left-sided valves and prosthetic valves [11,12].

Difficult ethical and practical problems arise when patients who are actively abusing injection drugs develop recurrent IE and need valvular surgery. (See "Right-sided native valve infective endocarditis", section on 'Management'.)

For prosthetic valve IE — Early surgery for prosthetic valve endocarditis is indicated for IE complications similar to native valve endocarditis (eg, HF due to prosthetic valve dysfunction, paravalvular regurgitation, or intracardiac fistula; annular abscess, difficult-to-treat pathogen, persistent infection). (See "Surgery for prosthetic valve endocarditis".)

 

Role of valve surgery – When early surgery is indicated, it should not be delayed except for patients with major cerebrovascular complications (eg, hemorrhagic stroke) or those with high operative or poor long-term prognosis due to other medical problems. (See 'Role of valve surgery' above.)

 

•Native valve endocarditis – Patients with left-sided native valve endocarditis (NVE) frequently require early valve surgery due to the presence of one or more complications (eg, IE-associated valve dysfunction complicated by heart failure [HF], intracardiac abscess, difficult-to-treat pathogen, or persistent infection). (See 'For native valve IE' above and "Surgery for left-sided native valve infective endocarditis".)

 

•Prosthetic valve endocarditis – Early surgery for prosthetic valve endocarditis is indicated for IE complications similar to NVE (eg, HF due to prosthetic valve dysfunction, paravalvular regurgitation, or intracardiac fistula; annular abscess; difficult-to-treat pathogen; or persistent infection). (See 'For prosthetic valve IE' above and "Surgery for prosthetic valve endocarditis".)

Perivalvular abscess — Perivalvular abscess should be suspected in the setting of conduction abnormalities on electrocardiogram (ECG) and/or persistent bacteremia or fever despite appropriate antimicrobial therapy [10]. The reported incidence of perivalvular abscess among patients with IE is 30 to 40 percent [11-13]. The aortic valve and its adjacent annulus are more susceptible to abscess formation and associated complications than the mitral valve and annulus [11-13]. This was illustrated in an autopsy study including 95 patients with native valve endocarditis; annular extension of infection was more common in patients with aortic valve compared with mitral valve endocarditis (41 versus 6 percent) [11].

 

Perivalvular abscesses can extend into adjacent cardiac conduction tissues, leading to heart block. Involvement of the conducting system is most common in the setting of aortic valve infection, especially when there is involvement of the valve ring between the right and non-coronary cusp; this anatomic site overlies the intraventricular septum that contains the proximal ventricular conduction system. Conduction abnormalities have been reported in 11.5 percent of cases of endocarditis [9]. Rarely, perivalvular infection can result in extrinsic coronary compression and can cause acute coronary syndrome [14]. (See "Diagnosis of acute myocardial infarction".)

 

Perivalvular abscess is associated with increased risk of systemic embolization and death. In one study including 73 patients with IE, the embolization rate was approximately twice as high among patients with perivalvular abscess (64 versus 30 percent) [12]. Another study including 118 patients with IE noted higher mortality among patients with perivalvular abscess (23 versus 14 percent) [13]. In addition, the presence of moderate or severe regurgitation is associated with higher mortality rate [15].

 

Data are conflicting regarding correlation between vegetation size and risk for perivalvular abscess. Large vegetation size had been implicated as a risk factor for perivalvular abscess in some series, although subsequent studies have shown no correlation [12,16]. Patients with IE involving congenital bicuspid aortic valves appear to be more prone to perivalvular complications than those with IE involving tricuspid aortic valves [17]. Injection drug use may be another risk factor for perivalvular abscess [12].

 

Transesophageal echocardiography (TEE) is more sensitive for detection of myocardial abscess than transthoracic echocardiography (TTE) [18]. In one study including 43 patients with perivalvular abscess documented at surgery or autopsy, the sensitivity, specificity, and positive and negative predictive values of TEE were 87, 95, 91, and 92 percent, respectively [13]. The sensitivity of TTE was much lower (28 percent), although the specificity was 99 percent. While TEE is more sensitive than TTE for detecting abscess, even TEE may miss abscess in difficult imaging situations where calcification, for example of the mitral annulus, obscures perivalvular tissues. Also, abscesses are more difficult to detect before they cavitate, and repeat TEE may be required if suspicion remains high. (See "Role of echocardiography in infective endocarditis", section on 'Perivalvular abscess or fistula'.)