**5. Therapy**

As well described and discussed at length in several chapters of this book, successful management of endocarditis requires a multidisciplinary approach. Clearly targeted and appropriate antibiotics are necessary. Prolonged courses of intravenous antibiotics are often prescribed, and fortunately, most patients can receive their therapies as an outpatient with close follow-up. While social and economic variables, not to mention restrictions by insurance companies and funding agencies, may limit options, fortunately from a medical standpoint, most patients will tolerate a prolonged course of antibiotics.

However, the critical decision-making regarding treatment for endocarditis is focused on appropriate interventional or surgical management. When associated with pacemaker lead systems or intracardiac devices, especially in the setting of large vegetations and resistant organisms or fungal infections, current guidelines advocate early and aggressive removal of all artificial material. Obviously, this can be quite challenging from not only a technical standpoint when the patient is quite sick but also how to support a patient that may be pacemaker-dependent in the setting of an infected pacemaker lead system. While many such devices can be removed percutaneously, there is often concern that large vegetations or lead systems that are firmly adherent to cardiac structures such as the tricuspid valve may require open heart surgery with direct removal [16]. Again, such cases illustrate the importance of a multidisciplinary team approach to not only the timing of interventions but also the specific procedures that may be required to remove the offending hardware.

The greater challenge is the timing of surgical intervention in patients who may require valve surgery—either repair or replacement—especially in the setting of associated other intracardiac pathology. Historical paradigms of prolonged courses of antibiotics and delayed surgical intervention, often after completion of a course of antibiotics, have been challenged recently as current European and American Society guidelines are tending to advocate early and aggressive surgical intervention. It was believed previously that early surgery and patients with active infections and vegetations were associated with a prohibitive risk for reinfection and postoperative complications from operating on septic patients. This was the rationale for delayed surgery after a prolonged course of antibiotics [17]. However, this approach was frequently criticized as selecting only those patients who survived complication free to complete their course of antibiotics, while potentially undertreating those patients who may have benefited from aggressive debridement and infection source control and who ultimately died of either overwhelming septic complications or catastrophic neurological events. A randomized trial of 37 patients with left-sided endocarditis, severe valvular disease, and large vegetations compared early surgical intervention with conventional medical therapies and potential delayed interval surgery and concluded that early surgery had a significant impact in reducing further embolic events and death [18]. Unfortunately, as a function of the nature of the disease combined with associated comorbidities, randomized trials dealing with surgical management of infected endocarditis can be very difficult. Current guidelines acknowledge this fact and base their recommendations on the growing body of literature that consists predominantly of small series and high-quality observational studies [19]. Nevertheless, the current guidelines suggest early surgical intervention in those patients who present with the following characteristics:


Similar recommendations are used to guide therapy in patients with prosthetic valve endocarditis [20]. However, it must be considered that overall, prosthetic valve endocarditis can be very difficult to successfully manage medically.

A growing challenge is the population presenting with right-sided endocarditis especially in the setting of poly-microbial or resistant organisms from intravenous drug abuse. Again, historically because of the concerns of recurrent infections or relapse, there was reluctance to intervene early, and many of these patients were treated medically. However, there is growing evidence that tricuspid valve surgery should be considered in those patients with worsening right heart failure from tricuspid regurgitation, failure of medical therapy, difficult to treat organisms, vegetations greater than 2 cm, and worsening pulmonary complications from presumed septic pulmonary emboli. Obviously, the challenge is not only patient selection but also surgical timing—again emphasizing the importance of a multidisciplinary team to sort out the clinical issues [21]. Historical management of tricuspid pathology was often "vegectomy" or "valvectomy" [22]. While there were some survivors of such therapy, without doubt, the developing of acute and chronic right heart failure and the consequences of it—such as hepatic congestion and failure—limit the practical application of such approaches [23]. Rarely is right-side infections managed with procedures that result in severe regurgitation—a pathophysiology that is often the initial indication for intervention.

Nevertheless, the growing consensus is that patients with severe valvular infections especially in the setting of failure of appropriate medical therapy, worsening vegetations, systemic complications, and especially worsening heart failure should be promptly evaluated and considered for early, if not urgent, surgical intervention. Obviously, the risks and benefits of surgery in a septic patient with associated comorbidities must be evaluated on a case-by-case basis and take into consideration vocal experiences and resources.
