CASE STUDY | CATHETER SHEATH
Optimising Steerable Catheter Performance: Improving Planar Bending Stability and Kink Resistance
How systematic structural optimisation helped address shape instability while improving anti-kinking performance, pushability and torque transmission.
>45°
Original planar deviation
<8°
Optimised planar deviation
>90°
Bending angle with lumen ovality maintained
THE CHALLENGE
When steerable catheter performance depends on precise mechanical control.
During design validation of a customer’s steerable catheter, the deflection segment exhibited radial deformation during steering. The bending plane also deviated by more than 45° from the pull-wire exit orientation, resulting in inaccurate tip steering and reduced device deliverability.
01
RADIAL DEFORMATION
The deflection segment experienced radial deformation during steering, affecting structural stability and lumen geometry.
02
PLANAR BENDING DEVIATION
The bending plane deviated by more than 45° from the pull-wire exit orientation, reducing steering accuracy and predictability.
THE SALT MEDICAL APPROACH
Re-engineering the catheter for improved bending stability
Salt Medical applied a systematic steerable catheter design optimisation approach, evaluating the shaft material architecture, reinforcement, braid design, and pull-wire positioning. The objective was to improve planar bending stability, reduce radial deformation, and maintain lumen integrity during high-angle catheter deflection.
Material & reinforcement architecture
Redesigned the outer shaft material architecture and incorporated nitinol coil reinforcement within the deflection segment to improve resistance to radial deformation.
Gradient braid architecture
Replaced the uniform braid density with a gradient PPI design to improve deformation resistance while supporting controlled bending behaviour.
Braiding & pull-wire process optimisation
Redesigned the braiding die and optimised the spring configuration to improve pull-wire positioning and planar bending stability.
THE RESULT
Reducing planar deviation for more accurate steering
Following the engineering optimisations, planar bending deviation was reduced from more than 45° to within 8°. The optimised catheter demonstrated improved steering accuracy, greater resistance to compression, and maintained lumen ovality during bending angles greater than 90°.
≤8°
OPTIMISED PLANAR DEVIATION
Steering accuracy
Improved tip steering and more predictable catheter deflection.
Compression resistance
Improved resistance to radial deformation during steering.
Lumen integrity
Lumen ovality maintained during bending angles greater than 90°.
Device deliverability
Smooth device passage through the working lumen.
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