Abstract

Objective The optimal timing of valve surgery in left-sided infective endocarditis (IE) is undefined. We aimed to examine the association between the timing of valve surgery after IE diagnosis and 6-month mortality among patients with left-sided IE.

Methods We analyzed data from a retrospective cohort of patients with left-sided IE who underwent valve surgery within 30 days of diagnosis at a tertiary center. The association between time from IE diagnosis to surgery and all-cause six-month mortality was assessed using Cox proportional hazards modeling after adjusting for the propensity score (to undergo surgery 0 to 11 days versus > 11 days, median time, after IE diagnosis) and other confounders.

Results Of 546 left-sided IE cases seen between 1980 and 1998, 129 (23.6%) underwent valve surgery within 30 days of diagnosis. The median time between IE diagnosis and surgery was 11 days (Range=1-30). There were 35/129 (27.2%) deaths in the surgical group. Using Cox proportional hazards modeling, propensity score and longer time to surgery (in days) were associated with unadjusted HRs of (4.18, 95% CI, 1.44-12.14) and (0.93; 95% CI, 0.88-0.99), respectively. In multivariate analysis, longer time to surgery was associated with an adjusted HR, (0.97; 95% CI, 0.90-1.03). The propensity score was strongly correlated (r = - 0.63) with the time from diagnosis to surgery suggesting collinearity between the two variables.

Conclusion The results of our study suggest the presence of collinearity between the propensity to undergo early valve surgery in IE and the timing of surgery making it difficult to establish the individual effect of each variable on the outcome. Yet, we note that the hazard ratio for each day delay in time to surgery remains in the protective direction.