100 QUESTIONS IN CARDIOLOGY

44 What is the risk of stroke each year after a)

tissue or b) mechanical MVR or AVR? What is the

annual risk of bacterial endocarditis on these

prosthetic valves?

Tom Treasure

The risk of stroke after valve replacement is higher in mechanical

than tissue valves (in spite of best efforts at anticoagulation) and

is higher after mitral than aortic valve replacement. The risk is

very much higher in the first year.

To some extent these numbers depend on definition and how

hard you look. I quote from our own prospective randomised trial

((iinn pprreessss))of St Jude and Starr-Edwards valves so the information

was deliberately sought and the follow up was very near

complete. The annual incident rate of complications (per 100

patient years) is shown in Table 45.1.

TTaabbllee 4444 .. 11 TThhee aannnnuuaall iinncciiddeenntt rraattee ooff ccoommpplliiccaattiioonnss ((ppeerr 110000 ppaattiieenntt
yyeeaarrss))

SSttrrookkee TTIIAA NN ““EEvveennttss””

Mechanical mitral 2.4 4.2 380 6.5
Mechanical aortic 1.0 1.3 870 2.0
Tissue mitral 0 2.5 600 2.5
Tissue aortic 1.8 0.7 80 1.5

My final column “events” summarises and rounds the events and

one could give this number to a patient, qualified by the statement

that most are mild and recover.

From the same source we found that endocarditis risk was

under 1% per annum.