3. Treatment

#### 3.1 Medical treatment

The same fundamental aspects about the antibiotic therapy in IE is applied to the right-sided endocarditis, making emphasis in the early and proper setting of the cultures, the prompt and adequate starting of empirical antimicrobial therapy (if the suspicious of IE is higher), and the administration of a culture-antibiogram sensible antibiotic.

One aspect that changed in the antimicrobial treatment of RSIE in comparison with LSIE is the duration of the therapy when the implicated bacteria is the methicillin-sensible Staphylococcus aureus, due to the 2015 European Society of Cardiology guidelines for the management of infective endocarditis recommending a short treatment of 2 weeks in this scenario. This approach is attributed to the less aggressive evolution of RSIE with these bacteria [5].

The prophylactic treatment in the patient with high suspicion of RSIE should cover Staphylococcus aureus, streptococci, and enterococci and should include penicillinase-resistant penicillins or vancomycin, depending on the local prevalence of methicillin-resistant Staphylococcus aureus (MRSA) [6].

#### 3.2 Surgery treatment

In RSIE, the medical treatment usually resolves the disease; nevertheless, the surgery for right-sided infective endocarditis is recommended in the following situations: (1) right-heart failure due to severe tricuspid valve regurgitation, (2) inability to eliminate bacteremia or organisms resistant to culture-directed antibiotic treatment, within 7 days, and (3) tricuspid valve vegetations >20 mm [1–3, 5].

During the surgery, most of the infected tissue must be removed; if it is possible, we should try to repair the native valve but guarantee the adequate functioning of the valve. When a valve-sparing is impossible, the implantation of a prosthetic valve is necessary, always trying to use the less foreign material to diminish the risk of IE recurrence [14].

Sometimes the endocardial destruction is highly extensive that compromises the valve repairing as well as the valve prosthesis replacement; this scenario is hideous and requires the reconstruction of the annular structure using endocardium patch or other materials.

Another potential complication of IE can be the formation of ventricular septal defect due to the infection's aggressiveness which can show communication between the right ventricle and left ventricle through the membranous septum. This anatomical defect also can be figured out with a pericardium patch [15].

Some surgeons can feel uncomfortable with the idea of setting up a prosthetic valve in tricuspid position due to being afraid of high gradients through the valve and the potential thrombosis of the prosthesis. However, large prostheses (>30 mm) guarantee low transvalvular gradients, and the incidence of thrombosis is small if the patient has an adequate anticoagulation control (biological and mechanic prostheses are anticoagulated). Moreover, bioprosthesis degeneration develops more slowly owing to the low-pressure conditions in the right ventricle [6].

In 1991, Arbulu et al. published a paper showing their experience in tricuspid valvulectomy without replacement, generally indicated for IVDA, to avoid the potential IE recurrence; nevertheless, about 25% of patients cannot tolerate tricuspid regurgitation and require a second operation for tricuspid valve replacement [14, 16].

#### 4. Prognosis

RSIE implies a better prognosis than LSIE; the previous study revealed the mortality of right-sided IE is 12% in-hospital patients and 0–7.3% for surgical patients. However, these percentages increase at least twice in patients with intensive care unit (ICU) admission; actually, this issue will be described forward [3, 9].

Concomitant left-sided IE carries a worse prognosis than right-sided infection alone, due predominantly to its greater likelihood for invasion and abscess formation [7].

## 5. Prevention

The high increase of bacterial resistance throughout the last decades has produced a change in the IE guidelines from 2002. The same criteria for LSIE are applied to RSIE regarding the antimicrobial prophylaxis, being reserved only in patients with a high risk of endocarditis, particularly those with PVIE [5].

Nevertheless, there are some aspects that the last IE guidelines do not approach which are very relevant that need to be highlighted. One of the most critical issues is the quite strict aseptic measurements that healthcare professionals must take during routine procedures, especially invasive maneuvers in high-risk patients such as immunocompromised, hemodialytic (HD), cyanotic congenital heart disease (CHD) patients, etc.

The change in some hospital policies can diminish the incidence of bacteremia and IE, such as have been shown in some publications [17].

#### 6. RSIE in intensive care units (ICU)

There are few publications about the characteristics of RSIE in ICU. It is noteworthy that patients with IE admitted in ICU have a higher rate of morbidity and mortality than non-ICU patients. The only study describing the outcome of IDUs with RSIE needing ICU admission reported a mortality of 26% [2].

Some factors have been associated with a worse prognosis: acute respiratory failure requiring mechanical ventilation, shock, Simplified Acute Physiology Score (SAPS II) ≥ 20, and Sequential Organ Failure Assessment (SOFA) ≥ 3 [2, 5].

#### Right-Sided Infective Endocarditis DOI: http://dx.doi.org/10.5772/intechopen.85019

Other elements that play an essential role at the 30-day survival are age <45 years, Charlson score < 3, endocarditis diagnosed before ICU admission, aminoglycoside use, the presence of septic pulmonary embolism, and a single surgical indication for patients needing a surgical procedure [2].

Reasons for admission to the ICU were a congestive cardiac failure (64%), septic shock (21%), neurological deterioration (15%), and cardiopulmonary resuscitation (9%). Younger patients have a better prognosis because they usually present a minimal dysfunction of the right-sided valve, low risk of pulmonary embolism, and reasonable response to appropriate antibiotic therapy [2].

Opposite to the last IE guidelines, which no longer recommend the aminoglycosides in the treatment of native valve staphylococcal endocarditis, Georges et al. found a better survival in their patients treated with a combination of penicillins or vancomycin with gentamicin [2].
