Why would I use a Nylon Millar Catheter over a Polyimide one, or vice-versa?

The only difference between thePolyimideandNyloncatheters is a slight variance in the stiffness of the lumen. The Polyimide catheter material can feel slightly stiffer than it's Nylon counterpart.
否则使用其中一种材料做not confer any advantages - it is purely a matter of preference.