Endocarditis After TAVR on Par With Surgery, Lethal for Both

Patrice Wendling

November 06, 2019

More detailed data from the PARTNER program show similar risks of endocarditis after transcatheter and surgical aortic valve replacement (TAVR/SAVR), although the consequences of infection remain profound.

The overall incidence of prosthetic valve endocarditis (PVE) per 1000 person-years was 5.06. For TAVR, it was 5.21 and for SAVR, it was 4.10 (incidence rate ratio [IRR], 1.27; 95% confidence interval [CI], 0.70 - 2.32; P =.44).

Despite the vastly different access routes, PVE rates were comparable between standard surgical AVR and transfemoral TAVR (IRR, 1.27; P = .44) and transthoracic TAVR (IRR, 1.27; P = .49), the authors reported today in Circulation.

"It's very reassuring," senior author Wael Jaber, MD, of the Cleveland Clinic Foundation in Ohio, told theheart.org | Medscape Cardiology. "Right now I can walk into a patient's room and if they ask 'what is the risk of this valve getting infected?' I actually have for the first time, probably in valve replacement history, objective evidence of how high the rate of infection is and what are the bugs we have to deal with. The concerning part is trying to figure out why some patients, very few patients, were reoperated on."

Prior reports on this rare, but often lethal, complication after SAVR have been typically derived from single-center retrospective experiences, while data in TAVR are less well characterized. This is the first centrally adjudicated evaluation of PVE in patients with TAVR and SAVR, he said.

For the analysis, the investigators identified 8530 patients from the PARTNER 1A and 1B high-risk randomized cohorts, PARTNER 2A intermediate-risk randomized cohort, PARTNER 2B randomized Sapien XT cohort and nested registries, and the PARTNER 2 Sapien 3 high-risk observational cohorts. A total of 7273 patients underwent TAVR and 1257 underwent SAVR.

Over an average 2.6 years of follow-up, there were 107 definite PVEs adjudicated based on the modified Duke criteria. Of these, 95 occurred after TAVR and 12 after SAVR. Two-thirds of the PVE cases were high-risk patients having Society of Thoracic Surgeons Predicted Risk of Mortality scores of at least 8, and 31.8% were from inoperable PARTNER cohorts.

The timing of infection was similar between the two groups, with most cases occurring between 31 days and 1 year (median, 0.87 years). "So this was most likely not a procedure-related event," Jaber said.

In multivariate analysis, independent predictors of PVE were baseline cirrhosis (IRR, 2.86), pulmonary disease (IRR, 1.70), and renal insufficiency (IRR, 1.71). PVE was not associated with TAVR or SAVR. Contrary to prior studies, no associations were seen with age, sex, diabetes, aortic insufficiency, or orotracheal intubation, possibly because patients in this study were older and most procedures were done in the operating room under general anesthesia, the authors suggest.

In an effort to control for the study's disproportionate number of high-risk patients, a competing-risk analysis was performed, in which the adjusted risk of PVE remained comparable after TAVR and SAVR over 5 years (HR, 1.15; 95% CI, 0.58 - 2.28).

The study also showed for the first time that infecting organisms are distinct between the two procedures. Staphylococcus was the more common PVE pathogen in SAVR compared with TAVR (58.3% vs 28.4%; P = .04), while streptococcal infections trended higher in TAVR (28.4% vs 8.3%; P = .14).

Although enterococcus has been well documented in TAVR PVE, infection rates were similar in both groups (P = .75). This is important because it was initially thought that the genitourinary and groin pathogen would put transfemoral TAVR at higher risk for PVE than SAVR, Jaber noted.

"Although the pathogens were slightly different, we didn't see this massive number of patients with E coli infection, gut infection in the TAVR group and that's very reassuring," he said. "That means people are following proper sterilization procedures. The fears, at least in the community about this, were not founded."

PVE, however, was associated with a more than fourfold mortality risk (hazard ratio [HR], 4.42; 95% CI, 3.42 - 5.72), with 46% of patients with no PVE and 96.2% with PVE dead from all causes at 5 years.

"Once you have endocarditis, you're almost destined to die," Jaber said. "I've been doing this for over 20 years and I've never seen a Kaplan-Meir survival curve do this, ever."

The database was not granular enough to determine whether the valve was seeded, for example, by a tooth abscess, urinary tract infection, or colon cancer but raises the question of whether clinicians should be more aggressive with antibiotics in AVR patients, he said.

In addition, 8.3% of patients had aortic valve reintervention after SAVR-PVE but only 1.1% after TAVR-PVE.

"We should try to push our surgical colleagues to operate as much as they can to save these patients, especially when we start dealing with younger patients, more viable, with many years left to live," he added.

"As the use of TAVR expands to lower risk patients, understanding and characterizing mechanisms of valve failure becomes increasingly important," the authors concluded.

Commenting for theheart.org | Medscape Cardiology, Josep Rodés-Cabau, MD, Quebec Heart and Lung Institute, Quebec City, Quebec, Canada, praised the authors for examining an important issue but said the degree of novelty is "relatively limited" because the results are relatively similar to prior studies in TAVR patients, including the largest multicenter registry study, which he co-authored, and a recent Danish national registry.

"But the strength is that we are talking here about randomized trials, which are PARTNER 1 and 2, and comparing the endocarditis events between transcatheter and surgical cases."

While it's reassuring that TAVR has no more endocarditis than SAVR, he questioned whether event rates should be lower, given that TAVR is a minimally invasive procedure, the chest isn't opened, and patients go home more rapidly. At the same time, studies have shown vegetation attached not only at the level of the valve but at the stent frame and higher rates of pacemaker implantation in TAVR patients.

Also unclear is the influence of more aggressive antibiotics and the fact that many TAVR cases are performed in cath labs rather than surgical ORs, where sterility and other conditions may be different.

"I think that we have many questions," Rodés-Cabau said. "Yes, we are equal to surgery but my point is we can do better."

The PARTNER trials were funded by Edwards Lifesciences. Jaber reported core laboratory contrasts with Edwards Lifesciences. Several coauthors reported financial relationships with Edwards. Rodés-Cabau reported institutional research grants from Edwards, Medtronic, and Boston Scientific.

Circulation. Published online November 6, 2019. Abstract

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