Current best practices and guidelines indications for surgical intervention in infective endocarditis

Current treatment options for patients with endocarditis: The evolving indications for cardiac surgery

Infective endocarditis (IE) is a serious and deadly disease. Despite medical advances over the past half century, more than one half of patients with IE suffer a serious complication, and the mortality rate remains approximately 20% during the initial hospitalization and approaches 40% at 1 year. In patients with documented IE, the treatment centers on two main aspects: effective antibiotic therapy and consideration of surgical therapy. Effective antibiotic therapy is the mainstay of treatment and focuses on sustained bactericidal concentrations tailored specifically to the causative microorganism. Surgical therapy is also an important option for many patients with IE. The goals of surgical therapy are to eradicate the focus of infection, to repair endocardial destruction, and to prevent the development of complications and relapse of infection. Ideally, surgical therapy should offer a survival advantage over medical therapy alone. Recent evidence supports the survival benefit of surgery in patients with IE, specifically in those with heart failure and complicated, left-sided IE. Future therapeutic strategies may include broader indications for surgery, as well as new treatments such as immune-modulating agents.

Aortitis in a child with Abiotrophia defectiva endocarditis

Abiotrophia defectiva, one of several nutritionally variant Streptococcus species, is an uncommon but important cause of endocarditis in children. We describe an unusual case complicated by extensive aortitis with pits in the ascending aorta and the proximal aortic arch.

Recent trends in infective endocarditis: influence of case definitions

PURPOSE OF REVIEW

Infective endocarditis continues to pose major challenges in diagnosis and management despite advances in understanding the epidemiology, microbiology, and pathology of the disease. The purpose of this article is to provide a review of diagnosis, microbiology, and treatment of infective endocarditis, particularly as they are influenced by case definitions.

RECENT FINDINGS

Case definitions have a critical effect on the interpretation of trends in infective endocarditis, and recent studies have proposed more specific criteria. Studies have also addressed the appropriate use of echocardiography to assist in the diagnosis and management of infective endocarditis. Staphylococcus aureus has become an increasingly common cause of infective endocarditis, and the microbiology of nosocomial infective endocarditis is changing. Newer techniques are being used to aid in the identification of causal agents in blood culture-negative infective endocarditis. Antimicrobial guidelines for the treatment of infective endocarditis are readily available, including a proposal to avoid premature discharge of patients on outpatient antibiotic therapy. Additional studies have been conducted on combination antibiotic therapy, duration of treatment, dosing of aminoglycosides, alternative agents for gram-positive organisms, aspirin therapy, and surgical interventions.

SUMMARY

Recent trends in diagnosis, microbiology, and treatment of infective endocarditis are described, and case definitions play a critical role in their interpretation.

Infective endocarditis

Despite improvements in health care, the incidence of infective endocarditis has not decreased over the past decades. This apparent paradox is explained by a progressive evolution in risk factors; while classic predisposing conditions such as rheumatic heart disease have been all but eradicated, new risk factors for infective endocarditis have emerged. These include intravenous drug use, sclerotic valve disease in elderly patients, use of prosthetic valves, and nosocomial disease. Newly identified pathogens, which are difficult to cultivate--eg, Bartonella spp and Tropheryma whipplei--are present in selected individuals, and resistant organisms are challenging conventional antimicrobial therapy. Keeping up with these changes depends on a comprehensive approach, allying understanding of the pathogenesis of disease with the development of new drugs for infective endocarditis. Infection by staphylococci and streptococci is being dissected at the molecular level. New ideas for antimicrobial agents are being developed. These novel insights should help redefine preventive and therapeutic strategies against infective endocarditis.

Infective Endocarditis in Patients with Kidney Failure: Chronic Dialysis and Kidney Transplant

Physicians who treat patients with infective endocarditis (IE) are encountering a growing number of dialysis and kidney transplant patients. Both groups have 30 to 100 times higher risk of IE, with 1-year mortalities of 40% to 60%. The predominant organisms causing IE are gram positive, with 60% to 80% of cases due to Staphylococcus aureus, and another 10% to 20% of cases due to coagulase-negative staphylococci. Renal transplant patients may develop fungal IE, but this risk is primarily in the first 3 months after transplant. In addition to blood cultures, transesophageal echocardiogram is the most useful diagnostic examination for IE in these patients. Initial antibiotic therapy, pending final culture and antibiotic susceptibility results, should provide coverage against the most common organisms and allow for the potential of either methicillin or vancomycin-resistant species. Removal of infected hemodialysis access devices and at least 4 to 6 weeks of intravenous antibiotics are recommended. Antibiotic prophylaxis against IE has been recommended for all dialysis and renal transplant patients, but this strategy is controversial and unproven.

Infective Endocarditis in Elderly Patients

Infective endocarditis (IE) in elderly patients is a serious disease with significant morbidity and mortality. IE presents unique diagnostic and therapeutic challenges in the elderly. A heightened index of suspicion is necessary due to the atypical presentations of IE among the elderly. Underlying degenerative valvular disease, mitral valve prolapse, and presence of a prosthetic valve are important predisposing risk factors for IE in the elderly. IE in the elderly is somewhat more common in men. The mitral valve is affected somewhat more frequently compared with the aortic valve. Streptococci and staphylococci are the predominant organisms, recovered in approximately 80% of elderly patients with IE. The presence of calcific valvular lesions and prosthetic valves often confound echocardiographic findings in the elderly. Aggressive diagnostic and therapeutic approaches are mandatory for a favorable outcome of IE in this group of patients.