By Jeffrey Zimmet, MD, PhD
Associate Professor of Medicine, University of California, San Francisco; Director, Cardiac Catheterization Laboratory, San Francisco VA Medical Center
SYNOPSIS: In this analysis of a large registry of transcatheter aortic valve replacement patients with confirmed endocarditis, most were treated with antibiotics without surgery. In-hospital and one-year mortality rates were high and were not much better in patients who underwent surgery.
SOURCE: Mangner N, del Val D, Abdel-Wahab M, et al. Surgical treatment of patients with infective endocarditis after transcatheter aortic valve implantation. J Am Coll Cardiol 2022;79:772-785.
The incidence of infective endocarditis (IE) after transcatheter aortic valve replacement (TAVR) is thought to approximate that seen after surgical AVR. It is possible approximately 50% of patients presenting with IE after surgical AVR are treated surgically. For post-TAVR patients, the rate of surgical treatment of IE could be much lower than this, but the results of surgical treatment vs. antibiotics alone are not well-described.
The Infectious Endocarditis After TAVI International Registry contains data from 604 patients diagnosed with definite IE from 59 centers in 11 European countries collected between June 2005 and November 2020. Of these, 111 patients were treated surgically, with the remainder treated with antibiotics alone. The median age of patients in the study was 81 years. The calculated operative risk for these patients, as estimated by the logistic EuroSCORE, was more than 14%.
More than two-thirds of patients presented in the early phase post-TAVR, with a median time from procedure to IE symptoms of 5.7 months. Almost one-third of patients presented with IE more than one year after TAVR. The TAVR valve itself was involved in 60% of cases, with mitral valve involvement second most common at approximately 15%. The causative organisms seen most commonly were Enterococci, Staphylococcus aureus, and coagulase-negative Staphylococci, with so-called oral Streptococci accounting for more than 13% of cases. Six percent of patients were culture negative. Healthcare-associated infections were judged to be the source of IE in 44.2% of cases.
Compared with patients treated with antibiotics alone, those who underwent surgery were more likely to show involvement of the TAVR valve itself or of the annulus. Vegetation size greater than 10 mm, presentation with heart failure, systemic embolization, and persistent bacteremia were predictors of treatment with cardiac surgery, while older patients and those with neurologic symptoms were less likely to undergo surgery. Among patients treated surgically, a little more than half underwent isolated aortic valve replacement, with aortic root replacement required in 9% of patients.
Unsurprisingly, the mortality rate in this group of patients was high. Approximately one-third died during the initial admission for IE, and half died within one year. Recurrence of IE occurred in more than 12% of patients. There was no significant difference between surgically and medically treated patients in terms of in-hospital mortality, one-year mortality, or two-year mortality. An adjusted analysis restricted to patients with involvement of the TAVR valve itself likewise showed no significant differences between patients treated with surgery and those treated with antibiotics alone. The authors concluded most patients with TAVR who develop subsequent endocarditis are treated with antibiotics alone. Treatment with surgery was not associated with improvements in short-term or one-year mortality rates.
COMMENTARY
The main conclusions of this study seem intuitively true, yet it is helpful in clinical practice to be able to point to real statistics from well-performed observational studies. The high mortality rate of post-TAVR patients who acquire IE should come as no surprise. Still, the reported ~30% in-hospital mortality rate and ~50% death rate at one year lend some perspective in evaluating such patients. Recurrence was elevated, too, at more than 12% for the entire cohort. While early mortality was high, patients who survived the first year enjoyed relatively favorable outcomes. One-year mortality was 47.9%, with two-year mortality only marginally higher at 55.1%. These numbers should be interpreted with some caution, given only the therapy assigned during the index hospitalization for IE was used to define treatment strategy. The nature of these specialized TAVR referral centers also may result in skewing the population toward higher-risk patients.
The fewer than one in five patients who were treated surgically during the index admission lies in stark contrast to the roughly half who are treated aggressively among surgical prosthetic valve endocarditis patients. The reasons for this appear obviously related to elevated baseline surgical risk and are reflected in the older age and greater comorbidities that define the average TAVR patient.
Because both surgical and medical treatments are associated with poor outcomes, the authors made the case for focusing on prevention and early diagnosis of IE. Considering they reported more than 40% of post-TAVR IE cases were secondary to healthcare-associated infections, there is a need for new prevention methods in higher-risk patients.
In this analysis of a large registry of transcatheter aortic valve replacement patients with confirmed endocarditis, most were treated with antibiotics without surgery. In-hospital and one-year mortality rates were high and were not much better in patients who underwent surgery.
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