Infective Endocarditis After TAVR Rare but Has Serious Consequences: SwissTAVI

The risk of infective endocarditis is low in real-world patients who undergo TAVR, new data from the SwissTAVI registry show. But when infections do occur, the consequences can be devastating,

Compared with patients who did not develop endocarditis after TAVR, those who did had a HR for mortality of 6.55 (95% CI 4.44-9.67) and a HR for stroke of 4.03 (95% CI: 1.54-10.52). The incidence of infective endocarditis was 1.0 events per 100 person-years over 5 years of follow-up. Among those who  developed endocarditis, independent predictors included younger age, male sex, absence of balloon predilatation prior to valve implantation, and having undergone TAVR in a cath lab rather than a hybrid operating room.

Commenting on the study for TCTMD, Philippe Généreux, MD (Morristown Medical Center, NJ), said that while it doesn’t establish causality, the sobering consequences of endocarditis should motivate even established operators to do everything possible to minimize the risk.

“For me, this paper will lead to some reassessment of my behavior during TAVR procedures and regarding prophylaxis after,” said Généreux. He noted that he recently saw a young TAVR patient with endocarditis that arose from a Staphylococcus aureus infection related to eczema.

“With younger patients I think what typically happens is they are more active than our elderly patients, so there is more chance of them getting cut, getting infections. Also, they may be less concerned if they were to cut themselves and not really thinking this is a big deal,” he added. “What we say to patients is to use antimicrobial prophylaxis for 6 months when they go to the dentist. But maybe there are other activities that they are doing, or other reasons that they have, where we they need protection also.”

There's clearly different bacteria that cause endocarditis in TAVR than after surgery, which is interesting. Knowing this will potentially help with strategies to prevent its occurrence. Philippe Généreux

For the study, published online June 15, 2020, in the Journal of the American College of Cardiology, Stefan Stortecky, MD (Bern University Hospital, Switzerland), and colleagues looked at 7,203 patients who underwent TAVR at 15 hospitals in Switzerland between 2011 and 2018 and were included in the SwissTAVI registry. The incidence of infective endocarditis was 1.0 events per 100 person-years over 5 years of follow-up.

In the SwissTAVI cohort, endocarditis risk was highest in the early periprocedural period, with a median time from procedure to infection of 196 days, or roughly 6 months. Of the microorganisms most frequently associated with infections, Streptococcus spp were the most common (28.9%), followed by Enterococcus spp (26.2%), and Staphylococcus aureus (21.5%). Among infective endocarditis that occurred early, Enterococcus spp were found to be the most frequent causative microorganisms (33.3%).

Although 92.6% of patients who developed endocarditis had received antibiotic prophylaxis, it was found to be ineffective in nearly half of them.

To TCTMD, Généreux said knowing what microorganisms to anticipate is extremely useful. “There's clearly different bacteria that cause endocarditis in TAVR than after surgery, which is interesting. Knowing this will potentially help with strategies to prevent its occurrence,” he commented.

In SAVR, Stortecky and colleagues write, Staphylococcus aureus and coagulase-negative staphylococci are the most common microorganisms implicated in endocarditis, with low reported rates of enterococcal and viridans group streptococcal infections. While the authors say they can only speculate as to why this difference in microbial risk occurs, it could be attributed to a variety of things such as age and skin susceptibility at the access site. Either way, the findings point to the need to broaden the coverage for microbial prophylaxis in some TAVR patients, they conclude.

“Based on the observed differences in the spectrum of pathogens between surgical and transcatheter heart valve interventions, a change in antibiotic prophylaxis for transcatheter heart valve interventions to an intravenous dose of amoxicillin/clavulanic acid, ampicillin/sulbactam, or vancomycin in patients allergic to penicillin may be reasonable,” the researchers write. However, they caution that with antibiotic resistance growing worldwide, “it remains to be demonstrated whether a change in antibiotic prophylaxis is effective to mitigate the risk of periprocedural endocarditis.”

Best Practices in the Cath Lab

In an editorial, Bernard D. Prendergast, MD (St Thomas’ Hospital, London, England), and colleagues note that although the SwissTAVI cohort was not compared with surgical patients, the findings “confirm the body of evidence suggesting that the incidence of [prosthetic valve endocarditis] after TAVR does not differ significantly from the incidence after surgical aortic valve replacement.”

They add that the findings should prompt individual center to review whether their antibiotic prophylaxis regimens are sufficient to protect TAVR patients against local isolates of Enterococci. The editorialists also point to the increased risk associated with TAVR performed in the cath lab as an opportunity for interventional cardiologists to ensure that they are following best practices similar to those of an operating room, from sterile technique and wound preparation to gloving and gowning.

Généreux agreed, noting there should not be a higher price to pay in the form of infections for patients to have a minimalist approach.

“Maybe we need to take a step back and be a little bit more cautious to avoid these complications. They are rare, but it would be great to eliminate them or at least reduce them,” he said. “I’m not saying we should not do cases in the cath lab, but we should have the same standard of sterility.”

He added that medical clearance prior to TAVR also may need to be modified to reflect disparate risk in young versus old patients, and that consideration may need to be given to extending prophylaxis to a year in some patients.