A clinicopathologic study of prosthetic valve endocarditis in 22 patients: morphologic basis for diagnosis and therapy.

Although endocarditis is a frequently lethal complication of prosthetic valve replacement, there is little pathological information on which to base diagnosis and treatment. We have studied the clinical and pathological features of 22 patients with prosthetic valve endocarditis seen at The Johns Hopkins Hospital over the past 17 years. Five patients developed endocarditis within two months of operation and 17 between two and 48 months (average 12) after operation. Patients dying early had a more fulminant course and their endocarditis was less often recognized during life. Late deaths, tending to present with fever and bacteremia unmasked by postoperative problems, were more readily recognized. Mitral and aortic prosthetic endocarditis generally led to a different type of prosthetic valve dysfunction: nine of 14 aortic valve prostheses with endocarditis developed incompetence and one other stenosis; five of seven patients with mitral valve prostheses developed stenosis and one, a homograft, developed incompetence. Prosthetic valve dysfunction led to death in 10 patients (45 per cent) and embolic events in five (23 per cent), including four cerebrovascular accidents. Ring infection, often believed to be universally present, and a contraindication to surgery, was found only in 50 per cent of these patients. In four patients (18 per cent) the endocarditis was sterilized by antibiotics but death occurred from valve dysfunction or emboli. These findings suggest that early surgical intervention combined with antibiotics has a chance of providing effective therapy for prosthetic valve endocarditis.