[Polygraphic indices of wearers of Hancock bioprostheses normally functioning in the aortic position].

A phonomecanocardiographic study in 33 patients who had undergone aortic valve replacement with a glutaraldehyde-preserved Hancock bioprosthesis, has been carried out 6 to 42 months after surgery. All xenografts were considered well functioning on the basis of clinical, electrocardiographic and radiographic evaluation. Typical phonocardiographic features of a well functioning porcine heterograft in aortic position were considered 1) an opening snap of variable intensity recorded in about 50% of the patients; 2) a normal closing sound; 3) a protosystolic ejection murmur which was always present and whose intensity was inversely related to the prosthesis size; and 4) the absence of a diastolic murmur. The anatomical and functional characteristics of the aortic valve of the pig are suggested to explain both the absence of a diastolic murmur and the pattern of the closing sound, which is undistinguishable from that of a normal aortic valve. Moreover, the reduced pliability of the right coronary cusp of the porcine valve, due to the muscular shelf at its base, with consequent limitation of the effective prosthetic orifice and relative stenosis of the device correlates well with both the opening snap and the sytolic ejection murmur.