The effects of hammer pressure on cellular response in a porcine heart valve tissue.

Our objective was to design, develop, characterize and validate a prototype device for testing the response of aortic valve tissue to impact forces. With each cardiac cycle, the aortic valve, on closure, is subjected to a substantial impact force and the ability of valvular interstitial cells to withstand such forces without apoptosis has not been examined. Our aim was to correlate impact force with apoptosis, identifying the latter using a terminal transferase dUTP nick end-labelling (Tunel) assay. With our drop tower design, we created reproducible impact forces on heart valve tissue resulting in cellular trauma. The reliability of the impact tester design were verified and results showed that normal tissue can withstand impact forces more than 30× greater than the physiological forces to which the tissue is normally exposed. This provides a wide safety margin and indicates that bioengineered aortic valve tissue should have similar properties if it is to withstand physiologic forces long term.