In recent years, steerable catheters have been developed to combat the effects of the dynamic cardiac environment. Mechanically actuated steerable catheters appear the most in the clinical setting; however, they are bound to a number of mechanical limitations. The aim of this research is to gain insight in these limitations and use this information to develop a new prototype of a catheter with increased steerability. The main limitations in mechanically steerable catheters are identified and analysed, after which requirements and solutions are defined to design a multi-steerable catheter. Finally, a prototype is built and a proof-of-concept test is carried out to analyse the steering functions. The mechanical analysis results in the identification of five limitations: (1) low torsion, (2) shaft shortening, (3) high unpredictable friction, (4) coupled tip-shaft movements, and (5) complex cardiac environment. Solutions are found to each of the limitations and result in the design of a novel multi-steerable catheter with four degrees of freedom. A prototype is developed which allows the dual-segmented tip to be steered over multiple planes and in multiple directions, allowing a range of complex motions including S-shaped curves and circular movements. A detailed analysis of limitations underlying mechanically steerable catheters has led to a new design for a multi-steerable catheter for complex cardiac interventions. The four integrated degrees of freedom provide a high variability of tip directions, and repetition of the bending angle is relatively simple and reliable. The ability to steer inside the heart with a variety of complex shaped curves may potentially change conventional approaches in interventional cardiology towards more patient-specific and lower complexity procedures. Future directions are headed towards further design optimizations and the experimental validation of the prototype.

Additional Metadata
Keywords biomechanical testing/analysis, Biomedical devices, biomedical instrumentation, cardiovascular implants, cardiovascular system mechanics
Persistent URL dx.doi.org/10.1177/0954411919877709, hdl.handle.net/1765/120661
Journal Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine
Citation
Ali, A. (Awaz), Sakes, A, Arkenbout, E.A. (Ewout A), Henselmans, P. (Paul), van Starkenburg, R. (Remi), Szili-Török, T, & Breedveld, P. (2019). Catheter steering in interventional cardiology: Mechanical analysis and novel solution. Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine. doi:10.1177/0954411919877709