Statin use after valvular heart surgery is associated with a decreased risk of prosthetic valve endocarditis

Type of funding sources: Public hospital(s). Main funding source(s): Sanming Project of Medicine in Shenzhen, China;

HKU-SZH Fund for Shenzhen Key Medical Discipline

Prosthetic valve endocarditis (PVE) is a rare but serious complication following valvular heart surgery for which preventive strategies remain unknown. Recent epidemiological evidence suggests that statins may reduce the risk of infections and infection-related complications.

We aim to assess the association between statin use and the risk of prosthetic valve endocarditis in patients undergoing valvular heart surgery.

In all patients undergoing valvular heart surgery in Hong Kong between 2010 and 2021, statin use was ascertained by ≥14-day consecutive filled prescriptions after surgery. Stepwise Poisson regression was applied to identify predictors of PVE. Baseline characteristics between statin nonusers (N = 1400) with statin users (N = 976) were balanced using the inverse probability of treatment weighting. Cox proportional-hazard models with competing risk regression were further performed to estimate the risk of PVE and cardiovascular mortality associated with statin use.

Our study included 2376 patients; the mean age was 57.8±14.2 years, and 54.4% were males. Over a median follow-up of 5.5 years (interquartile range 2.8-8.6), PVE occurred in 93 patients (6.75 [95% CI 5.51-8.26] PVE events per 1000 person-years). PVE was associated with New York Heart Association Class (Relative Risk [RR] 1.22, 95% Confidence Interval [CI] 1.01-1.45; P = 0.035), prior infective endocarditis (RR 8.64, 95% CI 5.58-13.19; P < 0.001), and aortic valve replacement (RR 1.67, 95% CI 1.11-2.53; P = 0.014).

Compared with non-use, statin use was associated with a 47% lower risk of PVE incidence (multivariable-adjusted subdistribution hazard ratio [SHR] 0.53, 95% CI 0.33-0.83; P = 0.006) (Figure 1). This inverse association with the risk of PVE was duration dependent, with an adjusted SHR of 0.60 (95% CI 0.47-0.73; P < 0.001) per year of statin use. Results were consistent across subgroups of sex (male vs female), the number of valvular procedures (single vs multiple), and prosthesis type (mechanical vs biological), but not in groups aged ≤60 years or with prior infective endocarditis (Figure 2). Statin use was associated with a 45% decreased risk of cardiovascular death (SHR 0.55, 95% CI 0.36-0.84; P = 0.006).

In patients undergoing valvular surgery, post-operative statin use is associated with a lower risk of PVE. These results provide new avenues for preventing PVE and hence valve failure.