Abstract Body (Do not enter title and authors here): Introduction
Prosthetic valve endocarditis is a rare complication of aortic valve intervention, associated with high mortality and morbidity. There has been widespread growth in transcatheter aortic valve replacement (TAVR) use over the past decade including expansion to lower-risk and younger patients. Data on trends in incidence and outcomes of infective endocarditis (IE) after TAVR are sparse.

Research Question
With TAVR expansion, have there been any changes in the incidence of IE and 30-day surgical intervention and mortality, 2013-2022?

Methods
Using Medicare data, we analyzed 280,073 TAVR patients. Joinpoint regression was used to evaluate IE incidence, reported as annual percent change (APC). Adjusted Cox models were used to evaluate associations between IE incidence and procedure year, patient characteristics, and 30-day outcomes.

Results
IE incidence after TAVR decreased from 13.9/1000 person-years in 2013 to 10.6/1000 p-y in 2017 (APC=-7.7% [CI -12.2- -4.5%],p=0.01) and then was unchanged through 2022 (APC=0.9% [-0.3- 3.1%],p=0.23). Figure 1 depicts risk factors associated with post-TAVR IE. The reduction in non-elective procedures was associated with declining IE rates (p<0.001). After developing IE post TAVR, the 30-day risk-adjusted surgical intervention rate was 3.6% [3.1-4.1%].

In more recent years, patients were more likely to undergo such intervention within 30 days of IE diagnosis (sub-distribution HR (sHR):1.20 [1.12-1.29],p<0.001). Older IE patients (sHR:0.61[0.55-0.67],p<0.001), those on dialysis (sHR:0.48 [0.27-0.86],p=0.01) and those with permanent pacemakers (sHR:0.56 [0.34-0.93],p=0.03) were less likely to undergo intervention. The 30-day mortality risk of patient experiencing IE was 17.6% [16.8-18.5%] and remained similar across years.

Conclusion
In Medicare patients, the adjusted risk of IE after TAVR declined over time, which may relate to increasing experience with TAVR, procedural technique, and declining rates of non-elective interventions. Patients with IE were more likely to undergo surgical intervention over time, especially younger and lower surgical risk patients. Mortality rates remained high and did not change, emphasizing the need for more research on management practices.