between 1971 and 1975 , glutaraldehyde-preserved porcine aortic valve xenografts were employed for isolated replacement of the mitral valve ( mvr ) in 243 patients , replacement of the aortic valve ( avr ) in 167 patients , and double valve replacement ( avr and mvr ) in 51 patients .
C0003501
aortic valve
C0003506
replacement of