Long-Term Prognosis and Surgical Outcomes of Culture-Negative Infective Endocarditis

Culture-negative infective endocarditis (CNIE) presents significant diagnostic and therapeutic challenges due to the absence of identifiable pathogens, leading to empirical antibiotic treatment and potentially worse clinical outcomes. This study aims to compare the clinical characteristics, surgical outcomes, and long-term prognoses of patients with CNIE and culture-positive infective endocarditis.

A total of 698 patients who underwent surgery for infective endocarditis between 2013 and 2024 were included, with 154 (22.1%) classified as CNIE. Baseline, intraoperative, and postoperative factors were analyzed in several ways including multivariate Cox regression and structural equation modeling.

Patients with CNIE had worse preoperative cardiac and renal function and a higher incidence of postoperative renal replacement therapy. While overall long-term survival did not differ significantly between CNIE and culture-positive infective endocarditis, female patients with CNIE showed a significantly worse prognosis (hazard ratio, 2.13 [95% CI, 1.02-4.43]; P=0.04). Mediation analysis indicated that reduced renal function (estimated glomerular filtration rate) partially mediated the relationship between culture status and death, highlighting a potential mechanism.

Although the survival rates of patients with CNIE and culture-positive infective endocarditis are similar, the prognosis of female patients with CNIE is significantly worse.