Biomechanical assessment of the aortic root using novel force transducers.

In recent years the use of valve sparing techniques has become more common in selected patients with aortic valve insufficiency. However, limited experimental research has been performed to document the biomechanical effect of these techniques. One experimental platform is to evaluate how the normal physiological aortic root forces are altered or re-established after the surgical intervention. Hence, the aim of this project was to develop new implantable force transducers for a biomechanical description of various aortic root repair techniques. Two novel force transducers were developed. Both transducers were manufactured using rapid prototyping and were instrumented with miniature strain gauges. Before implantation both transducers were calibrated using a dedicated setup, yielding very linear correlation between the applied load and transducer output. The developed force transducers were implanted and tested in an 80kg porcine model. In the post-cardioplegic heart, the peak annular forces varied in the range of 2-4N and the commissural forces varied from 0.4 to 0.8N with a left ventricular pressure of 111mmHg. In conclusion, the two new force transducers to measure forces in the aortic root have successfully been developed. With these new devices a novel versatile and direct force measurement system has been provided.