Prosthetic Valve Endocarditis

Summary

Prosthetic valve endocarditis (PVE) was encountered in 42 out of 1810 patients (2.3%) who underwent valve replacement between 1971 and 1981. At an average follow-up time of 5.0 years (yr) the actuarial risk of PVE was 0.46 %/yr. The risk was lowest after aortic valve replacement (AVR): 0.37 %/yr, higher after mitral (MVR): 0.45%/ yr and highest after double valve replacement (AVR + MVR): 1.0%/yr. Bioprostheses (605 patients) were employed in large numbers after 1977; they had a higher actuarial risk of PVE than mechanical valves (1205 patients): 0.65 %/yr for bioprostheses versus 0.42 %/yr for mechanical valves. The risk of death was on the contrary, lower in the bioprostheses group: 0.12%/yr versus 0.19%/yr for mechanical valves. Medical treatment was attempted in 14 patients with 5 deaths (36%). The risk of death (surgery and medical treatment combined) was lower in AVR (27%) and higher in MVR (50%) and AVR + MVR (50%). Surgery carried the highest risk in emergency operations for prosthetic dysfunction (4/7 died); elective operations during or after medical treatment had no early mortality (7 patients). Medical therapy had a much higher success rate for bioprostheses (8/11 patients surviving, 73%) than for mechanical prostheses (9/31 patients, 29%).

Prosthetic valve endocarditis remains a highly dangerous, albeit rare, complication of valvular replacement. Early surgery is mandatory in cases of valvular dysfunction and the operation should be undertaken early for PVE of mechanical prostheses. A trial of medical treatment should first be attempted in bioprosthesis PVE.

Key words

Endocarditis - Valve replacement