3. Therapy

The management of patients with IE necessitates a multidisciplinary approach where cardiologists, cardiac surgeons, and infectious disease specialists are involved. There are no clinical randomized trials that guide the management decisions nor a level A evidence in international guides [8, 24].

require repairing of the underlying malformation. Valve repair and replacement are options for reconstruction, and there is no evidence that favors a bioprosthetic valve over a mechanical valve. Heart failure caused by valvular obstruction or regurgitation is the most common indication for surgery. A dismal prognosis is ensued when refractory pulmonary edema or cardio-

Table 2. Empirical treatment for different clinical scenarios in patients with suspected infective endocarditis.

All antibiotic doses are adjusted according to renal function. HACEK=Haemophilus spp., Aggregatibacter actinomycetem-

Empirical antibiotic regimen and dose Comment

Better activity than benzylpenicillin against enterococci and many HACEK bacteria; the use of gentamicin before availability of culture results is controversial

89

Surgical Management of Mitral Valve Endocarditis http://dx.doi.org/10.5772/intechopen.73679

> Activity against staphylococci (including meticillin-resistant Staphylococcus aureus)

Amoxicillin (2 g, every 4 h,

Vancomycin\* (dose as per local guidelines) + gentamicin\* (1 mg/kg of ideal bodyweight, every 12 h,

Vancomycin\* (dose as per local guidelines) + meropenem (2 g, every

Vancomycin\* (1 g, every 12 h, intravenously) + gentamicin\* (1 mg/kg, every 12 h, intravenously) + rifampicin (300–600 mg, every 12 h, orally or

intravenously)

8 h, intravenously)

intravenously)

intravenously) + gentamicin\* (optional; 1 mg/kg of actual bodyweight)

There is limited evidence to guide clinical practice when the patient has well-tolerated severe valve regurgitation and postpone surgery until stabilization with antibiotics. Complex or uncontrolled infection is the second indication for surgery. The complications include abscess, pseudoaneurysm, fistula, or atrioventricular block. A pseudoaneurysm is a perivalvular cavity that communicates with the cardiac chambers (evidenced by Doppler color), whereas an abscess is a pus-filled perivalvular cavity that does not communicate [19]. If perivalvular infection progresses, a fistula can be created (usually aorto-cavitary) which can have a mortality as high as 41% even with surgery [30]. Prevention of embolism is the third indication for surgery. This complication can affect 25–50% of patients [31]. Stroke is the most common presentation, but embolism resulting in end-organ infarction (kidney, spleen, coronaries, mesentery, and limbs) can also be present. Most emboli occur in the first 2 weeks after diagnosis with risk decreasing rapidly after antibiotics are instituted [32, 33]. Embolism is more likely when the vegetation is large (>10 mm), highly mobile, and located in the mitral valve [34]. Persistent or relapsing infection and infection caused by antibiotic-resistant microorganisms (e.g.,

S. aureus, S. lugdunensis, Pseudomonas, fungi) are also indications for surgery [27].

genic shock is present and no emergent surgery is done [28, 29].

comitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella kinga.

Regular measurement of serum concentrations needed to monitor and adjust dosing.

Native valve endocarditis—indolent

Native valve endocarditis— severe sepsis (without risk factors for multiresistant enteric Gram-negative

Native valve endocarditis—severe sepsis (with risk factors for multiresistant enteric Gram-negative

Prosthetic valve endocarditis—pending blood cultures or with negative blood

Adapted from Gould et al. [25].

presentation

bacilli, Pseudomonas)

bacilli, Pseudomonas)

cultures

\*

#### 3.1. Antibiotics

Antibiotics should be started once blood cultures have been acquired; nevertheless if the patient is stable, the physician could wait until final report is available [25]. Empirical antibiotic regimens for the native valve endocarditis and prosthetic valve endocarditis are outlined on definite guidelines by the British Society for Antimicrobial Chemotherapy (Table 2) [25]. Antibiotics can be modified according to culture results, local resistance patterns, virulence, and the presence or absence of prosthetic material. Because penetration of antibiotics to vegetations is difficult, prolonged parenteral antibiotic administration is advisable. Treatment for at least 4–6 weeks is usually necessary and longer for some cases (e.g., Q fever endocarditis).

#### 3.2. Surgery

About 40–50% of patients with IE undergo surgical therapy [26, 27]. Goals of surgery are removal of infected tissue and drainage of abscess, restoration of ventriculoarterial or atrioventricular continuity, and reversion to hemodynamic stability. In children, this process may


comitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella kinga.

\* Regular measurement of serum concentrations needed to monitor and adjust dosing.

Diagnosis of IE includes the sum of clinical findings, microbiological analysis, and imaging results. A definite diagnosis includes two major modified Duke criteria, one major plus three minor and five minor criteria [5]. Alternatively the diagnosis can be made by specimen culture or histology (obtained by surgery or autopsy) of the vegetation or abscess. The physicist must note that Duke criteria were devised to help in the diagnosis but never to replace the clinical judgment [17].

Infection of the mitral valve and its supporting structures is less frequent than aortic valve endocarditis but may be more indolent in its course. When S. aureus is the infecting organism, the mitral valve is more frequently involved ( 40% of cases) followed by the aortic valve in 36% of cases [18]. Echocardiography plays a major role in diagnosis and detection of complications. A major criterion includes the presence of valvular vegetation or abscess or new dehiscence of a prosthetic valve [19]. Besides diagnostic, echocardiography also provides information on the hemodynamic status of the valve lesion and left and right ventricular function. In native valve endocarditis (NVE), transthoracic echocardiography (TTE) has a sensitivity of 75% and specificity of >90% for detection of a vegetation. Transesophageal echocardiography (TEE) has a sensitivity >90% and should be done in a patient with a negative or equivocal TTE and high clinical likelihood of infective endocarditis [19]. As for abscess, leaflet perforation or pseudoaneurysm TEE offers better detection than TTE [20, 21]. In patients with prosthetic valves, the sensitivity of TTE is lower (36–69%), and TEE is more accurate in

The management of patients with IE necessitates a multidisciplinary approach where cardiologists, cardiac surgeons, and infectious disease specialists are involved. There are no clinical randomized trials that guide the management decisions nor a level A evidence in international

Antibiotics should be started once blood cultures have been acquired; nevertheless if the patient is stable, the physician could wait until final report is available [25]. Empirical antibiotic regimens for the native valve endocarditis and prosthetic valve endocarditis are outlined on definite guidelines by the British Society for Antimicrobial Chemotherapy (Table 2) [25]. Antibiotics can be modified according to culture results, local resistance patterns, virulence, and the presence or absence of prosthetic material. Because penetration of antibiotics to vegetations is difficult, prolonged parenteral antibiotic administration is advisable. Treatment for at least 4–6 weeks is usually necessary and longer for some cases (e.g., Q fever endocarditis).

About 40–50% of patients with IE undergo surgical therapy [26, 27]. Goals of surgery are removal of infected tissue and drainage of abscess, restoration of ventriculoarterial or atrioventricular continuity, and reversion to hemodynamic stability. In children, this process may

detecting complications and cardiac device infections [22, 23].

3. Therapy

88 Advanced Concepts in Endocarditis

guides [8, 24].

3.1. Antibiotics

3.2. Surgery

Table 2. Empirical treatment for different clinical scenarios in patients with suspected infective endocarditis.

require repairing of the underlying malformation. Valve repair and replacement are options for reconstruction, and there is no evidence that favors a bioprosthetic valve over a mechanical valve. Heart failure caused by valvular obstruction or regurgitation is the most common indication for surgery. A dismal prognosis is ensued when refractory pulmonary edema or cardiogenic shock is present and no emergent surgery is done [28, 29].

There is limited evidence to guide clinical practice when the patient has well-tolerated severe valve regurgitation and postpone surgery until stabilization with antibiotics. Complex or uncontrolled infection is the second indication for surgery. The complications include abscess, pseudoaneurysm, fistula, or atrioventricular block. A pseudoaneurysm is a perivalvular cavity that communicates with the cardiac chambers (evidenced by Doppler color), whereas an abscess is a pus-filled perivalvular cavity that does not communicate [19]. If perivalvular infection progresses, a fistula can be created (usually aorto-cavitary) which can have a mortality as high as 41% even with surgery [30]. Prevention of embolism is the third indication for surgery. This complication can affect 25–50% of patients [31]. Stroke is the most common presentation, but embolism resulting in end-organ infarction (kidney, spleen, coronaries, mesentery, and limbs) can also be present. Most emboli occur in the first 2 weeks after diagnosis with risk decreasing rapidly after antibiotics are instituted [32, 33]. Embolism is more likely when the vegetation is large (>10 mm), highly mobile, and located in the mitral valve [34]. Persistent or relapsing infection and infection caused by antibiotic-resistant microorganisms (e.g., S. aureus, S. lugdunensis, Pseudomonas, fungi) are also indications for surgery [27].

Surgery for IE is done through partial or full median sternotomy. Suppurative pericarditis suggests a previous perforation at the aortic or mitral ring or ring abscess [35, 36]. It is recommended to use bicaval cannulation to facilitate the procedure in the presence of burrowing abscess, acquired septal perforation, unexpected right-sided valve involvement, or complex aortic root reconstruction. Intraoperative TEE plays a major role in diagnosis and treatment guidance. When left-sided IE is present, minimal manipulation of the heart is important to avoid migration of embolic material. Ample excision of infected tissue is performed with drainage of abscess and closure of defects [37]. When mitral endocarditis is present, aortic valve involvement should be considered. Although absence of echocardiographic anomalies in the aortic area argue against the presence of vegetations and inspection of the aortic valve is not necessary. Reconstruction on mitral valve area can be accomplished when the vegetation is healed or small and the tensor apparatus is mostly uncompromised. Usual sites of native valve endocarditis are drop lesion of anterior leaflet or leaflet vegetation and ring abscess of posterior portion (Figure 1). Small perforations may be closed using autologous pericardium or bovine pericardial patch, or otherwise the defect may be closed using continuous suture (Figure 2). Reconstruction of the mitral valve represents a challenge if major involvement of the valves is present. Most of the times, a replacement is considered; nevertheless, the risk for PVE is greater especially in ongoing positive blood cultures. If commissural areas are compromised by the infection, a sliding annuloplasty can be performed. Partial leaflet resection, pericardial patch replacement of mid-leaflet areas, or both may be used [37]. The remaining orifice size after reconstruction must be large enough (25 mm in an adult, z-score 2 or greater in children) to prevent mitral stenosis [37]. Suture annuloplasty is preferable over prosthetic ring in active IE, but a biodegradable annuloplasty ring has been suggested by some authors [38]. In the absence of active IE (e.g., negative blood cultures, no inflammation), classical reconstruction techniques may be used for the mitral valve. Quadrangular resection of a portion of the posterior leaflet (Figure 3) or triangular resection of a portion of the anterior leaflet may be done, followed by the insertion

Figure 2. Pericardial patch used to close a drop lesion of the anterior leaflet.

Surgical Management of Mitral Valve Endocarditis http://dx.doi.org/10.5772/intechopen.73679 91

Figure 3. Limited quadrangular resection and sliding plasty of posterior leaflet.

Figure 1. Drop lesion of anterior leaflet and leaflet vegetation and ring abscess of posterior leaflet.

Figure 2. Pericardial patch used to close a drop lesion of the anterior leaflet.

Surgery for IE is done through partial or full median sternotomy. Suppurative pericarditis suggests a previous perforation at the aortic or mitral ring or ring abscess [35, 36]. It is recommended to use bicaval cannulation to facilitate the procedure in the presence of burrowing abscess, acquired septal perforation, unexpected right-sided valve involvement, or complex aortic root reconstruction. Intraoperative TEE plays a major role in diagnosis and treatment guidance. When left-sided IE is present, minimal manipulation of the heart is important to avoid migration of embolic material. Ample excision of infected tissue is performed with drainage of abscess and closure of defects [37]. When mitral endocarditis is present, aortic valve involvement should be considered. Although absence of echocardiographic anomalies in the aortic area argue against the presence of vegetations and inspection of the aortic valve is not necessary. Reconstruction on mitral valve area can be accomplished when the vegetation is healed or small and the tensor apparatus is mostly uncompromised. Usual sites of native valve endocarditis are drop lesion of anterior leaflet or leaflet vegetation and ring abscess of posterior portion (Figure 1). Small perforations may be closed using autologous pericardium or bovine pericardial patch, or otherwise the defect may be closed using continuous suture (Figure 2). Reconstruction of the mitral valve represents a challenge if major involvement of the valves is present. Most of the times, a replacement is considered; nevertheless, the risk for PVE is greater especially in ongoing positive blood cultures. If commissural areas are compromised by the infection, a sliding annuloplasty can be performed. Partial leaflet resection, pericardial patch replacement of mid-leaflet areas, or both may be used [37]. The remaining orifice size after reconstruction must be large enough (25 mm in an adult, z-score 2 or greater in children) to prevent mitral stenosis [37]. Suture annuloplasty is preferable over prosthetic ring in active IE, but a biodegradable annuloplasty ring has been suggested by some authors [38]. In the absence of active IE (e.g., negative blood cultures, no inflammation), classical reconstruction techniques may be used for the mitral valve. Quadrangular resection of a portion of the posterior leaflet (Figure 3) or triangular resection of a portion of the anterior leaflet may be done, followed by the insertion

90 Advanced Concepts in Endocarditis

Figure 1. Drop lesion of anterior leaflet and leaflet vegetation and ring abscess of posterior leaflet.

Figure 3. Limited quadrangular resection and sliding plasty of posterior leaflet.

of a partial or complete annular ring. When resecting the mitral valve, the posteroinferior zone of the mitral annulus should be inspected because myocardial ring abscess usually occurs in this location [39, 40]. When left atrioventricular discontinuity is present in mitral valve IE, a small variation of the usual valve replacement can be used. After thorough debridement of the affected tissue in the mitral ring, interrupted horizontal mattress sutures are anchored with felt or autologous pericardium pledgets to the ventricular aspect of the mitral annulus, brought up through the left atrial aspect and then through the prosthetic sewing ring. Deep bytes are performed [37]. When extensive ring abscess is present (Figure 4), a different approach is done. The atrioventricular discontinuity is reconstructed using an autologous or bovine pericardial patch. The ventricular aspect is anchored to the myocardium and endocardium using deep bytes of continuous 3-0 or 4-0 polypropylene suture. The superior aspect of this patch is anchored to the left atrial side with a continuous suture (Figure 5). The prosthesis is anchored to the ventricular aspect of the suture line using interrupted horizontal mattress sutures supported with felts pledgets (Figure 6) [37]. Using antibiotic, antiseptic solutions (e.g., povidone-iodine), or antifungal agents to impregnate the prosthesis and the affected area has been described to help in the management of this entity [41–43]. Mitral valve repair for IE continues to be challenging and much less commonly performed than valve replacement [44]. Repairing tissues that may be infected in the acute stages and the durability of repairing inflamed tissues are the main concerns influencing the decision [45–47]. Several studies have reported excellent results for mitral valve repair in IE [48–51].

4. Results

may be seated below the patch on ventricular wall.

Hospital mortality for valve operations in patients with IE varies widely (4–30%) [52–57]. This variation can be due to several factors, especially the difference in risk between the acute phase of IE and the healed stage. A study from Richardson reported a mortality of 14% in surgically treated patients versus 44% in those medically treated. Operative mortality was affected by urgency of operation.Mortality for elective operations (next convenient day), was 5%, for urgent operations (next day), 16% and for emergent operations in patients with cardiogenic shock (immediately), 33% [58].

Figure 6. Prosthesis is placed in position. The posterior suture line is on the patch in this case. Eventually the prosthesis

Figure 5. The defect is covered by a pericardial patch anchored within the left ventricle and extending up across the base

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of the posterior leaflet. Stitches then are placed to the left atrial wall.

Figure 4. Infective endocarditis with ring abscess compromising the posterior leaflet of mitral valve.

Figure 5. The defect is covered by a pericardial patch anchored within the left ventricle and extending up across the base of the posterior leaflet. Stitches then are placed to the left atrial wall.

Figure 6. Prosthesis is placed in position. The posterior suture line is on the patch in this case. Eventually the prosthesis may be seated below the patch on ventricular wall.
