Background-The role of valve surgery in left-sided infective endocarditis has not been evaluated in randomized controlled trials. We examined the association between valve surgery and all-cause 6-month mortality among patients with left-sided infective endocarditis. Methods and Results-A total of 546 consecutive patients with left-sided infective endocarditis were included. To minimize selection bias, propensity score to undergo valve surgery was used to match patients in the surgical and nonsurgical groups. To adjust for survivor bias, we matched the follow-up time so that each patient in the nonsurgical group survived at least as long as the time to surgery in the respective surgically-treated patient. We also used valve surgery as a time-dependent covariate in different Cox models. A total of 129 (23.6%) patients underwent surgery within 30 days of diagnosis. Death occurred in 99 of the 417 patients (23.7%) in the nonsurgical group versus 35 deaths among the 129 patients (27.1%) in the surgical group. Eighteen of 35 (51%) patients in the surgical group died within 7 days of valve surgery. In the subset of 186 cases (93 pairs of surgical versus nonsurgical cases) matched on the logit of their propensity score, diagnosis decade, and follow-up time, no significant association existed between surgery and mortality (adjusted hazard ratio, 1.3; 95% confidence interval, 0.5 to 3.1). With a Cox model that incorporated surgery as a time-dependent covariate, valve surgery was associated with an increase in the 6-month mortality with an adjusted hazard ratio of 1.9 (95% confidence interval, 1.1 to 3.2). Because the proportionality hazard assumption was violated in the time-dependent analysis, we performed a partitioning analysis. After adjustment for early (operative) mortality, surgery was not associated with a survival benefit (adjusted hazard ratio, 0.92; 95% confidence interval, 0.48 to 1.76). Conclusions-The results of our study suggest that valve surgery in left-sided infective endocarditis is not associated with a survival benefit and could be associated with increased 6-month mortality, even after adjustment for selection and survivor biases as well as confounders. Given the disparity between the results of our study and those of other observational studies, well-designed prospective studies are needed to further evaluate the role of valve surgery in endocarditis management.

The risk of symptomatic emboli associated with IE was reduced in patients who received continuous daily antiplatelet therapy before onset of IE.

HE REPRESENTATIVENESS HEUristic of the clinical features of infective endocarditis (IE) as described by Osler has undergone a significant change in developed countries. 1,2 Previously, IE was a disease that commonly affected patients with predisposing valvular abnormalities caused by rheumatic carditis, with viridans group streptococci the most common causative pathogens. 3 This presentation is currently seen in developing countries, where rheumatic heart disease is still prevalent. In developed countries, mitral valve prolapse (MVP) is now thought to be the most common predisposing cardiac condition in patients with IE. 2 Several recent studies from passively reported case series suggest that Staphylococcus aureus is now the most frequently identified causative pathogen. 1 These more recent clinical observations of IE characteristics, however, are based on data that come primarily from large, tertiary care centers 4,5 and may not reflect true changes in the epidemiology of IE but rather temporal changes in referral patterns. Thus, population-based investigations are needed to more accurately characterize IE in the United States. Olmsted County, Minnesota, is a setting uniquely qualified for the conduct of population-based studies of dis-See also pp 3012 and 3061.