effect of vegetation size on the outcome of infective endocarditis in intravenous drug users

background infective endocarditis is one of the most important complications of injection drug use, which is associated with significant mortality and morbidity. the aim of this study was to evaluate the influence of vegetation size and localization on outcome and in-hospital mortality of infective endocarditis. patients and methods a total of 34 patients were admitted to a university hospital in a four-year period and analyzed prospectively. injection drug users were defined as patients who had injected drugs intravenously within the past 3 months before admission. the diagnosis of infective endocarditis was made on the basis of modified duke‘s criteria. results totally, 38 episodes of endocarditis in 34 patients were identified. patients were all male with the mean (±standard deviation) age of 30.4±7.1 years. the affected valves were as follow: tricuspid valve in 26 cases (74.3%), mitral valve in 4 (11.4%), mitral and tricuspid valve in 4 (11.4%), and mitral and aortic valve in 1 (2.9%). the vegetation size was 10mm or less in 12 cases (34.29%), and more than 10mm in the remaining 23 cases (65.71%). eight patients (21.1%) underwent surgery, however, unfortunately, nine (23.7%) died. vegetations sized more than 10mm (p<0.033), involvement of the left-sided valves (p<0.012), and presence of more than one vegetation on tte or tee (p<0.05) were associated with higher probability of death. conclusion in contrast to some earlier studies which concluded that vegetations larger than 20mm are associated with higher mortality, our results revealed that the mortality rate increases even with smaller vegetations. in addition, the number and the location of vegetations also could affect the prognosis. therefore, lower threshold for surgical interventions should be applied in patients with vegetations larger than 10mm.