**5.3. Surgical treatment**

resistant (CA-MRSA). It is a predisposing factor in these patients and a challenge for physicians

*Streptococcus viridans* is currently considered to be the second cause of IE after *S. aureus*. Other pathogens such as *Enterococci* occupy the third place. The relevance of the latter is that its incidence has been increasing, plus it is more associated with nosocomial infection compared with *Streptococcus*. These pathogens if presented in prosthetic valves are more likely to cause intracardiac abscesses and less likely to have detectable vegetations on echocardiography than

In patients with ESRD, there is a malfunction in polymorphonuclear and mobility of granulocytes, which reduce defense of the patient's cells, thus failing to remove bacteria from the

As mentioned earlier the incidence of IE in HD patients is higher than in general population and it is caused by multiple factors. But it is closely related to frequent episodes of bacteremia related to dialysis access and the predisposition of these patients to present premature degeneration of the heart valves eventually causing bacterial implantation in the valves. This is an issue of major public health presenting a very poor prognosis in short and long term, with

Despite the high rates of IE and poor prognosis for these patients, there has not been a substantial change in mortality over the past two decades. This can be the result of not having important changes in the therapeutic armamentarium [25]. Reports of multiple studies have shown that left valves with IE in HD patients are affected twice the time compared to the right valves; as well as the mitral valve is affected in more patients than the aortic valve. It is theorized that the thickening of these valves, which is common in this group of patients, can lead to increased susceptibility to acquire IE because of alterations in the laminar flow. Mitral annular calcification, which is also common in ESRD, has also shown increased susceptibility to IE [8].

**5.1. Transthoracic echocardiogram (TTE) versus transesophageal echocardiogram (TEE)**

TTE as a first-line diagnostic tool can work, but Kamalakannan et al. reported only 55.3% positive for vegetations in IE in HD and after using TEE 92.5% were positive for vegetations [8].

Medical treatment for IE in HD patients, if considering the current guidelines for IE in general

population, must have some important considerations in this group of patients.

involved with patients with MRSA IE [1, 5, 24].

those presented in IE in native valves [1].

**5. Heart valves with IE in HD**

23.5% in-hospital mortality and 61.6% mortality in 1 year.

**4.9. Other microorganisms**

128 Contemporary Challenges in Endocarditis

**4.10. Immunosuppression**

bloodstream properly [5].

**5.2. Medical treatment**

You can repair a valve anytime with a TEE confirmation of good valve function, which is better than replacement.

Valve replacement is a key part of therapy in patients with IE [25]. A large retrospective study by Rankin et al. used the Society of Thoracic Surgeons national database to analyze 1862 valve surgery operations in dialysis patients with endocarditis from 1994 to 2003 and reported an operative mortality of 24.4%. In this study, several risk factors for hospital mortality were proposed in HD patients with IE, including (salvage surgery/shock, surgery on both valves, elderly, affected mitral valve, high BMI, arrhythmias, active endocarditis, and female gender) [26]. A more recent study of Leither et al. found lower mortality in patients who underwent surgery of left-sided surgery compared to those reported by Ranki et al.

Current indications for surgery in a patient with IE (general population) according to the guidelines are valve disease causing CHF, recurrent emboli, persistent despite appropriate antibiotic treatment infection, and mobile and large vegetation formation of myocardial abscesses. However, these recommendations are made for IE general population; currently, there are no specific guidelines for IE in HD patients, taking into account that this indication may be debatable for these patients. Dialysis patients have a higher risk for mortality in the context of IE, lower life expectancy, high surgical risk, and often other associated morbidities [25]. In this context, there are some studies with very different results: Spies et al. reported 73% mortality and Kamalakannan et al. reported 80% survival in patients undergoing surgery, in in-hospital survival and only 43% survival with medical treatment. However, in the study of Kamalakannan et al. 12 of the 15 patients (80%) survived, but 24 of the 69 patients had indication for surgery according to the guidelines of IE for the general population, indicating that selection bias likely strongly influenced the outcomes reported in these studies [8, 25, 27].

About surgical treatment in this group of patients, there has always been controversy over what type of prosthesis to be used: biological or mechanical. These controversies started from two studies from the 1970s that were case series (*n* = 4 patients) in dialysis, where accelerated calcification of biological valves was documented. Now there are enough studies that compare the use of mechanical versus. bioprosthesis with no significant differences. Thourani et al., in 2011, demonstrated a in HD patients with IE patients undergoing valve replacement of 18.1%, with no difference between mechanical and bioprosthetic after 10 years [28]. Other studies have shown a higher incidence of bleeding and cerebrovascular events in patients with mechanical valves compared with bioprosthesis. In addition to oral anticoagulants, which are problematic in ESRD patients, most patients are prone to bleeding.

Since no significant differences are found between the types of valve prosthesis to be placed in HD patients with IE, it is recommended to individualize each case. But as a general rule, bioprosthesis is placed in most HD patients with IE, especially in patients with increased risk of bleeding associated with anticoagulation, leaving mechanical prostheses for young patients without other morbidity in whom life expectancy is longer than the bioprosthesis and also, for young patients who are candidates for renal transplantation in the future [25].
