[312] Surgical Pathology of Native Valve Endocarditis in 310 Specimens from 287 Patients (1985-2004)

Mathieu C Castonguay, Kimberly D Burner, William D Edwards, Larry M Baddour, Joseph J Maleszewski. Mayo Clinic, Rochester, MN

Background: Few large studies have separately documented the clinical and pathologic features of native valve endocarditis from those of prosthetic valve endocarditis. Furthermore, surgical management of valvular endocarditis has evolved considerably in the past 20 years.
Design: A retrospective study of medical records from all patients undergoing surgery for native valve endocarditis at our institution between 1985 and 2004. Medical records were reviewed from 287 patients for demographics, infected native valve(s), infecting organism, risk factors for endocarditis, and pathologic features. Because 22 patients underwent removal of two or more affected valves, the study group included 310 valves. Histologically, slides were evaluated for the infecting organism(s) with tissue Gram and GMS stains.
Results: Patients ranged in age from 9-87 years (mean, 54). Of the 310 valves, 73% were from men and 84% were regurgitant. Risk factors for endocarditis included bicuspid aortic valve (23%), dental disorders (20%), mitral valve prolapse (17%), diabetes mellitus (16%), and others (< 5%, each); in 15%, no risk factor was identified. The four most commonly identified organisms were viridans streptococci (28%), Staphylococcus aureus (18%), coagulase-negative Staphylococcus (8%), and group D streptococci (10%). Native valve endocarditis was histologically active in 58% and healed in 42%, and affected the aortic position in 55%, mitral in 39%, and right-sided valves in 6%. It was associated with embolization in 29%, acute heart failure in 29%, and annular abscess in 20%. There were significantly more men in the aortic valve endocarditis cohort than in the mitral valve endocarditis cohort (81% vs. 63%, respectively; p=0.001). Among 182 valves with active endocarditis, 24.2% had no micro-organisms identified histologically, although purulent inflammation and focal cusp or leaflet destruction (along with positive blood cultures) were sufficient to establish a diagnosis of active endocarditis.
Conclusions: Native valve endocarditis affected men nearly three times as frequently as it did women. Male preponderance was 4:1 for the aortic valve but only 2:1 for the mitral valve. Diabetes mellitus emerged as a prevalent (and previously unrecognized) risk factor for infection of native valves. The most common infecting organisms were streptococci (45%) and staphylococci (26%). Micro-organisms were identified histologically in the majority of active endocarditis cases.
Category: Cardiovascular

Monday, March 19, 2012 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 50, Monday Morning


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