Miliary tuberculosis following homograft valve replacement

Abstract

Postoperative septicemia with infective endocarditis is a recognized complication of open heart surgery, in particular homograft or prosthetic replacement of cardiac valves. Several infective organisms, both bacterial and fungal, have been incriminated but infection due to tubercle bacilli has not yet been reported. During a 5 year period, over 800 homograft replacements in the aortic and/or mitral positions have been performed. Seven cases of miliary tuberculosis following homograft valve replacement are described here. In 3, there was a past history suggestive of tuberculous infection but necropsy failed to reveal any caseous or other tuberculous lesion apart from recent miliary tuberculosis. Vegetations on the homograft valves contained microcolonies of acid fast bacilli in most cases. Tubercle bacilli of the human type were recovered by culture or guinea pig inoculation in 6 of the 7 cases, and in 3 the diagnosis was established during life; 2 of these survived on antituberculosis chemotherapy. The onset of symptoms varied from a few wk to 12 mth after operation. The main presenting symptom was intermittent pyrexia. In 2 patients the diagnosis was made on radiologic and clinical grounds and in both, tubercle bacilli were grown from drill biopsy specimens of lung tissue. The source of infection was presumed to be the homograft valves contaminated in the postmortem room. The antibiotic mixture used in the sterilization of the homografts was not effective against tubercle bacilli.