Bileaflet mechanical heart valve closing sounds: in vitro classification by phonocardiographic analysis

Bileafl et mechanical heart valves, which exhibit hemodynamic performance fairly similar to that of native valves, can be investigated by the analysis of their closing sounds. Signal spectra calculated from the closing sounds are characterized by specifi c features that are suitable for the functional evaluation of the valves. Five commercial bileafl et mechanical heart valves were studied under different conditions that were simulated in vitro using a Sheffi eld pulse duplicator for the aortic position. The closing sounds were acquired by means of a phonocardiographic apparatus, analyzed by a specifi cally implemented algorithm, and were statistically compared. This article was aimed at classifying the investigated valves on the basis of their signal spectra: different profi les were identifi ed, depending on the working conditions; moreover, closing sound reproducibility and intensity allowed the ranking of valve performances with respect to the “noise” produced by valve closure. In particular, results demonstrated which valves were characterized by the lowest noise (i.e., the Medtronic Advantage and St. Jude Regent valves) and which were characterized by the highest reproducibility (OnX, Medtronic Advantage, and St. Jude Regent valves) under the examined experimental conditions.