Clinical Background

Minimally invasive surgery has become an increasingly popular option in the treatment of cardiovascular disease.  The risk and recovery time from traditional open heart surgery are reduced by performing catheter-based surgery.  A guide wire and catheter is  inserted into the femoral artery advanced through the vascular system to the site of disease.  Surgical tools such as angioplasty balloons can be deployed at the end of these catheters.  Guidant Corporation has become a world leader in the field of cardiovascular medical devices for catheter-based surgery.  But the development of the next generation of devices depends on how well the designers at Guidant can test and evaluate their products.  Currently available test methods, including animal models and simple plastic models, have significant limitations.  Neither model accurately simulates the human disease state or true in vivo conditions. 

In recent years, Guidant has developed a Synthetic Arterial Model (SAM) for product development and physician training in their European Training Center.  In the year 2002, over 1700 physicians used the SAM. The Guidant SAM is a simplified model of human anatomy from the knee to the neck.  The SAM uses lubricious, tissue-simulating materials create a modular vascular model of the major arteries.  The SAM is designed for plug-n-play with interchangeable arterial segments to replicate varying anatomy and disease states. The vasculature can be filled with water or blood at body temperature.  The model is fluoroscopically compatible.  The component materials have a radiopacity similar to tissue so that the surgical devices introduced into the model can be seen on x-ray.

 

Figure 1: (Top) Synthetic Arterial Model integrated into phantom body
(Bottom) SAM aorta

 

Figure 2: SAM heart under fluoroscope with contrast injected into coronary arteries

The Guidant SAM has many advantages over alternative pre-clinical models. However, the SAM lacks several necessary features to replicate in vivo conditions in human patients.  These features include pulsatile flow through the arteries at physiologic pressure, a beating heart and respiratory motion.  The incorporation of these features into the Guidant SAM would greatly improve the ability of Guidant engineers to evaluate their designs under surgical conditions. The improved clinical realism of the SAM would also increase physician comfort with the model and more importantly, Guidant medical devices.