By Stan Deresinski, MD, FACP, FIDSA

Clinical Professor of Medicine, Stanford University

Dr. Deresinski reports no financial relationships relevant to this field of study.

SYNOPSIS: While the incidence of infective endocarditis after transcatheter aortic valve replacement is low, the resultant morbidity and mortality is severe. Enterococci were the leading cause, a finding that raises questions about appropriate peri-procedural antibiotic prophylaxis.

SOURCE: Regueiro A, Linke A, Latib A, et al. Association between transcatheter aortic valve replacement and subsequent infective endocarditis and in-hospital death. JAMA 2016;316:1083-1092.

The introduction of transcatheter aortic valve replacement (TAVR) has become an important therapeutic modality for patients with significant aortic stenosis for whom valve replacement surgery is believed to represent an unacceptable risk. Among the complications of this procedure is the development of endocarditis. Regueiro and colleagues examined the incidence, causes, and outcomes of infective endocarditis (IE) after TAVR.

The investigators examined a registry that collected data from 2005-2015 from 47 sites in Europe and the Americas and identified 250 cases of definite IE among 20,006 patients who had undergone TAVR, yielding an incidence of 1.1% per person-year. The infection had an early onset in 178 (71.2%), with 72 of these cases occurring within the first two months after TAVR. Risk factors for the development of IE were younger age (in an overall well-aged population; mean ages, 78.9 vs. 81.8 years), male gender, diabetes mellitus, and moderate to severe aortic regurgitation. Approximately one-half of infections were deemed to be healthcare-associated.

A potential source of infection was identified in approximately one-third of cases. Four-fifths of IE cases presented with fever, while two-fifths had acute heart failure. A vegetation was detected by echocardiography in two-thirds, and concomitant mitral valve involvement was identified in 20%, while the tricuspid valve was affected in 4.4%; 6.0% had involvement of pacemaker devices. Eighteen percent had periannular complications. Enterococci were the most frequent cause of the infection, accounting for 24.6% of cases, closely followed by Staphylococcus aureus (23.8%) and coagulase-negative staphylococci (16.8%). This relative ranking persisted when only early onset cases were considered. The frequency of enterococcal IE, however, was greater in patients with early onset IE when compared to those with late onset infection.

Surgery was performed during the index hospitalization in 14.8% and non-surgical interventions were performed in 4%, including, in 1.2%, TAVR valve-in-valve implantation. The overall in-hospital mortality was 36%. Among those surviving their first episode, 9.4% experienced a second episode of IE. The two-year mortality was 66.7%, with 14 of 50 deaths due to infection-related complications.

COMMENTARY

The incidence of post-TAVR IE found in this large study covering an entire decade was similar to that reported after surgical placement of a prosthetic cardiac valve, although early onset was approximately twice as frequent as reported after the latter procedure.

The finding that the most frequent etiologic pathogens were enterococci differs from most series of endocarditis cases, including those involving prosthetic valves. As pointed out by the authors, this may be a result of the transfemoral approach through an area that may be colonized with enterococci and is also consistent with a greater proportion of early onset, as opposed to late onset, IE caused by these organisms. This has potential implications for antibiotic prophylaxis, since enterococci are resistant to the antibiotic most commonly used for surgical prophylaxis. One approach may be to use vancomycin alone or, perhaps, a combination of vancomycin and cefazolin for this purpose.