Cavitation threshold ranking and erosion characteristics of bileaflet heart valve prostheses

In vitro testing was approached using two methods in specially designed cavitation testers. Each method tested production model bileaflet valves with the sewing cuffs removed. First level testing evaluated the visual cavitation thresholds of size 25, 27, and 29 CarboMedics (CPHV), Saint Jude Medical (SJM) and Duromedics (original design prior to 1990 revision) valves using high-speed videographic methods to observe and record the presence of cavitation bubbles generated by each valve upon closure. Visual cavitation thresholds were also determined for size 29 Sorin and Jyros valves. The visual cavitation threshold dP/dt value was 2,500 mmHg/sec for the size 25 SJM and CPHV and 1,600 mmHg/sec for the size 25 Duromedics valve. Second level testing assessed the erosion resistance of size 25 CPHV, SJM, and Duromedics valves cycled at identical drive conditions. Upon visual inspection, damage to the Duromedics valves appeared to be much more severe than on either the CPHV or the SJM valve. Erosion damage observed on the CPHV appeared to be identical to that observed on the SJM valve. All Duromedics valves tested were of the original design (prior to the 1990 revision) and the effects of the sewing cuffs on the cavitation threshold and erosion were not evaluated in this investigation.