**5.2 Surgical techniques**

 The *principles of surgery* for tricuspid valve IE comprise debridement of infected tissue; excision of vegetations with valve conservation or valve repair; and removal of the TV with its replacement [16, 76, 81]. In case of *native pulmonary valve*, its preservation is usually recommended. If pulmonary replacement is mandatory, the utilization of a homograft or xenograft is favored.

 Various techniques that are used in cardiac surgery for right-sided IE [71, 81, 82]:


Importantly, first line of surgical techniques in IDUs is vegetectomy and valve repair [23].

*Valve repair* is mainly achieved with autologous pericardial patch, artificial chordae, and simple annuloplasty with sutures (Kay's or De Vega annuloplasty) [23]. Ruptured chordae may be restored with polytetrafluoroethylene neo-chordae [16].

In a single perforated valve leaflet (cusp) can be used either untreated or glutaraldehyde-treated autologous or bovine pericardial patch [16]. *Pericardial patch reconstruction* aims to avoid the use of any prosthetic materials [23]. Autologous pericardial patch repairs small defects by direct closure in case of one leaflet. It is also used in wide excision or debridement of one leaflet or two leaflets [23].

 *Bicuspidalization annuloplasty* is done after total excision of the posterior leaflet of tricuspid valve. Importantly, septal leaflet excision of TV has high risk of postoperative atrio-ventricular block [23]. This technique is accomplished either by Kay's annuloplasty or De Vega annuloplasty. Both Kay's annuloplasty and De Vega annuloplasty are the first choices indication for valve repair mainly in IDUs [23]. After broad resection (>75%) of the anterior leaflet of TV, it is recommended using of prosthetic or pericardial annular ring [23].

*Kay's annuloplasty* is mainly done after the total resection of a leaflet, and it is accomplished by the placement of fixing sutures in the corresponding segment of annulus to create a bicuspid valve [23].

*De Vega annuloplasty* (**Figures 3** and **4**) is based on fixing of two semi-circular purse string sutures between the anteroseptal commissure to the posteroseptal commissure with tricuspid annular reduction [23, 83]. This leads to the coaptation of the residual two leaflets.

*Valve replacement***.** Valve replacement is *required* in case of a large destroyed valve with increased pulmonary pressures and pulmonary vascular resistance [16, 76, 81]. It also requires the absence of drug addiction during surgery and after surgery [23]. Presently, it is recommended tricuspid valve excision for right-sided IE in IDUs [23].

#### **Figure 3.**

 *Operative procedures. (A) After the prolapsed leaflet segments and chordae were excised, the anterior commissural defect was made. (B) The defect was closed with an elliptical pericardial patch of 2.0 × 1.0 cm size. An adjustable DeVega-type annuloplasty using two continuous 5–0 Polypropylene sutures was performed to select an appropriate-size ring for complete leaflet coaptation. (C) A 26-mm Edward MC3 ring was placed using two interrupted, pledgeted 2–0 Dacron sutures and two continuous 3–0 polypropylene sutures. The anterior horn of the rigid ring (black arrow) was sutured to the medial end of the patch. NOTE: every figure specifies this sentence beginning: From Kim et al. [83]. It is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.* 

#### **Figure 4.**

*Operative findings. (A) The anterior commissure defect was closed with a patch (white arrow) and a rigid ring was placed along the functional valve opening. (B) The valve leaflets showed complete coaptation (white arrow) on saline test. NOTE: every figure specifies this sentence beginning: From Kim et al. [83]. It is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/ licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.* 

Valve replacement in IDUs is correlated with greater risk for recurrent infection and redo surgery (re-operation) [81]. It seems that mechanical prostheses and xenografts have similar outcomes [16]. However, recurrence of IE is mainly unchanged for mechanical and bioprosthetic valves [84]. Placement of a bioprosthetic valve may be challenging in case of IDUs with endocarditis considering the low compliance of IDUs for any treatment, risk of recurrent infections, risk of redo surgery, or valve generation. HIV is not a contraindication for surgery having good prognosis after it [85].

An important concern of tricuspid valve surgery is the damage of conduction system, which is higher in TV replacement [81, 86]. For instance, in case of 910 surgeries for tricuspid valve IE, there was higher risk of heart block in TV replacement (16%) versus TV repair (3%, *p* < 0.0001) [86].

Despite of published data supporting the greater risk of morbidity and mortality for multiple valve endocarditis [87], Weymann et al. outlined that single-valve endocarditis or multiple valve involvement have no different operative or postoperative risks [88]. In any type of prosthesis, survival on long-term is similar in any tricuspid valve replacement with prosthesis [89, 90]. Homograft tissue valve may be used after valvectomy mainly with cryopreserved mitral homograft [23].

IDUs have a greater mortality rate in comparison with the general population [91, 92]. However, right-sided IE treated surgically has good outcomes in the early, mid-term, and long-term [86]. Significant risk factors for poor prognosis in IDUs treated surgically are interrelated with the *Staphylococcus aureus* and fungi or polymicrobial IE, late presentation in critical condition, with the vegetation size, and with left-sided IE [93].

 Taking into account the current guidelines of The Society of Thoracic Surgeons Workforce on Evidence Based Surgery, European Society of Cardiology, and The European Association for Cardio-Thoracic Surgery, the **first line recommendation** (Class Ia) in IE for IDUs is the excision of infected tissue (vegetation) with valve repair. Furthermore, the second line recommendation (Class IIa) is tricuspid valve replacement. *Bioprosthesis* is the principal choice in TV replacement in IDUs, because mechanical valve needs long life anticoagulation [16, 23, 39, 81, 94, 95].

 A conservative approach is recommended by *European Society of Cardiology* in case of IDUs which present greater risk of recurrent infection. When valve replacement is necessary, bioprosthesis decreases the thromboembolism risk with no anticoagulant therapy on long term. On the other side, younger IDUs are disposed

#### **Figure 5.**

*The damaged bioprosthetic tricuspid valve with vegetations. NOTE: every figure specifies this sentence beginning: From Chen et al. [96]. It is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.* 

 to redo surgery or re-operation either because of recurrent infection or valve degeneration (**Figure 5**) [16, 96]. Moreover, valvectomy is the last choice to valve repair or valve replacement in IDUs with greater risk of recurrent infection. The valvectomy technique eludes the use of prosthetic material but is limited by residual severe tricuspid regurgitation with right heart failure. Published data supports this technique because of its long-term survival after complete valvectomy. For instance, one study of Gaca et al. reports tricuspid valvectomy as first choice only in 66 cases from 910 patients (7.3%) [86].

 Recurrence of IE is characteristically for IDUs [23, 97]. However, the best indication and timing of surgery are debatable [98]. Prognosis of IE in IDUs has good outcomes with mortality <5% [23]. Right-sided IE has a good prognosis with lower in-hospital mortality. As well, right-sided IE has a lower morbidity and mortality with better prognosis than left-sided IE but with greater early mortality rate [11, 21, 99]. Higher mortality in IDUs with right-sided IE is associated with vegetations >20 mm, fungal endocarditis, bacteremia, and older age [4, 13, 21, 59]. To sum up, the early and complete surgical debridement of infected tissue together with microbial therapy assures a good prognosis on long term [88].

#### **6. Conclusions**

 Right-sided IE is the primarily disease that affects IDUs and patients with congenital heart diseases [16]. Diagnostic findings comprise fever and respiratory symptoms [16]. In the main part of cases, *S. aureus* is responsible pathogen [16]. For IDUs with IE, optimal treatment strategies lack a general consensus. Majority of

*Infective Endocarditis in Intravenous Drug Users: Surgical Treatment DOI: http://dx.doi.org/10.5772/intechopen.84708* 

strategies are applied based on the team experience and the patient. Furthermore, this absence of evidence-based guidelines highlights that any IE should be managed by an "Endocarditis Team" [86]. Surgery is a choice only for difficult evolution, failure of medical therapy, or recurrent septic emboli to the lungs or paradoxical emboli [16].
