**9. Conclusions**

topic area is likely due to limited awareness and under-recognition of such clinical presentations. Within the microcosm of SE associated with IE, approximately 30–40% of events involve neurological manifestations [10, 122]. Beyond the more commonly seen complaints (e.g., stroke, transient ischemic attack, meningitis, brain abscess) within this subset, less frequently reported clinical manifestations may include visual loss, seizures, acute mononeuropathy, and even spinal cord involvement [122–124]. Septic emboli can migrate to the spinal cord, causing segmental infarction [122, 123]. These exceedingly rare events have the potential to result in severe disability and often accompany additional, simultaneous SE to other anatomic regions [10].

During the past two decades, significant increases have been noted in the number of valvular repairs, valve replacements, intracardiac devices and hemodialysis catheter placements [125–128]. Collectively, these procedures inherently create a small, but significant risk of IE, especially in patients with chronic comorbid conditions such as renal insufficiency, diabetes and autoimmune diseases [129–131]. Given the potential for major morbidity and mortality associated with IE in the setting of indwelling intravascular/intracardiac devices, the primary focus should be on prevention. Within this context, efforts include more selective device

implantation policies and better modulation of known post-implantation risks [132].

In terms of general diagnostic considerations, numerous guidelines and recommendations have been published to date. Although beyond the scope of the current discussion, certain aspects of these recommendations warrant a brief mention [133, 134]. One very important highlight is the emphasis on prompt echocardiography in cases of suspected IE, with TEE recommended if the initial TTE is negative and clinical suspicion remains high [8]. Echocardiographic imaging can then be repeated in 3–5 days if clinical symptoms/suspicion persist [8]. It is also suggested that patients with vegetations >10 mm in size, embolic events while on antibiotic treatment, and patients with >2 embolic events should be evaluated for surgical intervention [8]. One unique diagnostic consideration is the inability to use magnetic resonance imaging (MRI) in patients with certain types of intravascular devices/implants. Amraoui et al. recently described the use of positron emission tomography (PET) as an alternative method of identifying foci of SE in patients with implantable cardiac devices, with

Treatment options start with intravenous antibiotics, however in certain cases prompt surgical treatment is necessary. The American Heart Association developed guidelines to assist with identification of patients who require prompt surgical intervention [136]. Patients with IE who develop decreased left ventricular ejection fraction (LVEF) or a new aortic or mitral valve murmur require prompt surgery [50, 136, 137]. Patients with preserved LVEF that are stable and adequately managed on medical therapy do not need an immediate corrective surgery [138]. However, a recent study demonstrated that surgical intervention in the setting of CHF can reduce mortality from approximately 60–85% to 15–35% when compared to medical therapy alone [139, 140]. Patients who present with valvular vegetations >10 mm in size, or with multiple vegetations on imaging, are likely to benefit from surgery [136]. Another important indication for surgery is lack of improvement after 7 days of appropriate antibiotic

**8. Miscellaneous considerations**

160 Advanced Concepts in Endocarditis

limited success [135].

Despite significant clinical research and advances in clinical management, septic embolism associated with infectious endocarditis continues to be a diagnostic and therapeutic challenge. Given the increasing number of intravascular and intracardiac device implantations, as well as the greater prevalence of chronic comorbid conditions, it is not surprising that the incidence of both infectious endocarditis and septic embolism has followed suit. In this chapter, we outlined general pathophysiologic and anatomic considerations with which all physicians should be familiar. This important knowledge should serve to assist providers in maintaining a high level of clinical suspicion for potential IE and/or SE. Given the continued high rates of associated disability and mortality, more research is needed to better understand and treat these "low-frequency, high-impact" events.
