Prosthetic valve endocarditis (PVE) accounts for 10-30% of IE cases.  Both mechanical and bioprosthetic valves are prone to infection, particularly in the first 3 months postoperatively.  The overall incidence of PVE regardless of valve type and location ranges from 0.3-1.2% per year. PVE can be classified into early or late infection.  Early PVE is generally defined as infection occurring within 1 year of valve replacement. PVE can be acquired perioperatively, in the community setting or associated with healthcare contact.  Perioperative infection in both mechanical and bioprosthetic valves usually involves the sewing ring and leads to perivalvular dehiscence, annular abscess formation, pseudoaneurysms and fistulae. The rate of late PVE is higher in bioprosthetic valves compared with mechanical valves. Late PVE typically involves the leaflets of the prosthesis. Mitral and aortic positions are equally affected. Annuloplasty rings are less prone to IE than prosthetic valves.
Clinical signs and symptoms are similar to NVE but may be atypical in early PVE.  Fever is present in nearly all patients. A new and changing murmur is encountered half of the time.  Early PVE tends to be more fulminant with rapid deterioration due to congestive heart failure.  Emboli are infrequent in PVE.  The diagnosis of PVE is usually based on positive blood cultures.  Serial electrocardiogram may help identify conduction defects due to annular abscess.

Gross examination of the bioprosthesis reveals vegetations.