The Design of an Improved Force Focused Angioplasty Catheter

Abstract

Atherosclerosis is a disease that causes obstructions to develop within the arterial system; these obstructions can result in an acute vascular event such as a heart attack or stroke, and potentially death. In the majority of cases a standard angioplasty balloon is sufficient to dilate the site of an obstruction; however difficult obstructions, such as heavily calcified lesions require specialist dilation solutions. One such example of a device is Boston Scientific's cutting balloon. An analysis of the Food and Drug Administration's (FDA) Manufacturer and User Facility Device Experience (MAUDE) database demonstrates that the original cutting balloon has a number of distinct adverse events associated with it. In this study we describe the design, manufacturing, and testing of a new force focused angioplasty balloon that has the potential to reduce or eliminate the adverse events associated with the Boston Scientific cutting balloon. This design incorporates two elastomeric materials to aid recoiling of the device namely: nitinol and a silicone elastomer. New methods of manufacturing are described in this study, that ensure that precision molding and assembly can occur. To determine the effectiveness of our device, we simulated concentric calcified lesions with a surrogate chalk model. These results demonstrate that our device has a significantly lower lesion burst pressure in comparison to a standard angioplasty balloon, 174 atm versus 12.48 atm. To determine if our device reduced potential snagging, and thus reduced the risk of withdrawal resistance being encountered, we performed a withdrawal resistance test. A noticeably lower withdrawal force is associated with our device, the high peaks on the Boston Scientific device indicate that there may be wings forming on the balloon and these are catching on the tip of the introducer sheath. Finally, we demonstrated in vivo efficacy of our device in a porcine model. By the use of elastomeric recoiling features in a new cutting balloon design we have been able to overcome the three main reported adverse events associated with the Boston Scientific cutting balloon. Subsequently we experimentally demonstrated this improved efficacy for one particular peripheral balloon size (e.g., 5 mm diameter).