Improved catheters reduce complications

Many medical procedures require the use of catheters either in blood vessels or the urinary tract. However, this can result in clinical complications as well as patient discomfort.

Scientists on the EU-funded 'Understanding interactions of human tissue with medical devices' (UNITISS) project set out to develop advanced design strategies for catheter-based medical devices. The key objective was to reduce catheter-mediated complications.

To achieve their goals, a number of solutions for improved catheter design were investigated. They included improved catheter geometry and texture, advanced coatings and ways of measuring and minimizing the forces acting between the catheter and the human tissue. In order to test the improvements it was necessary to develop appropriate human tissue models.

Researchers found that currently-available synthetic tissue models were not capable of mimicking human tissue sufficiently. For this reason, many tests were carried out using an ex vivo porcine aorta model to simulate the interaction of the catheter with the tissue it comes into contact with. A series of in-house catheter designs were tested alongside specially-designed holders for the catheters and tissue.

Additionally, researchers evaluated the skin friction behaviour and tensile strength using ex vivo human skin, human dermis and tissue-engineered skin. Histological analysis alongside various spectroscopic and microscopic analyses was performed to better understand the mechanical response of human tissue to physical interactions and the subsequent tissue damage. The friction behaviour was also evaluated for in vivo human skin as well as porcine skin and synthetic skin models.

To minimise the side-effects of catheterisation, UNITISS developed improved polymer coatings for medical devices. These coatings are capable of interacting with water, and are lubricious and anti-bacterial to reduce tissue damage and infection, respectively.

Part of the project was also devoted to computer modelling of the catheter–blood vessel mechanical interactions and hydrodynamic behaviour. This information was ultimately used to design improved catheter tips.

The ultimate goal of UNITISS is to transfer the generated knowledge to the development of innovative clinical devices. Always with patient welfare in mind, achieving this goal is expected to benefit individuals that require catheterisation.