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Views: 33 Author: Site Editor Publish Time: 2024-08-12 Origin: Site
Microcatheterrefers to a reinforced catheter with a very small diameter. There is no strict size definition, but it is common to call a catheter with a diameter of 0.70~1.30mm a microcatheter. Microcatheters can be used for guidewire support, exchange, passing lesions, delivering embolic media, stents, etc. The fine structure enables it to shuttle in human blood vessels, so it is increasingly used in minimally invasive interventional surgery.
Most microcatheter designs consist of the following components:
Inner layer: lining, usually PTFE liner Middle layer: usually stainless steel braid or spring, or other metal materials Outer layer: usually Pebax, with different hardnesses as needed In addition, mandrel and fusion sleeve are auxiliary processes.
The middle layer of the microcatheter is usually called the middle reinforcement layer. It is usually designed by weaving or winding metal wires to increase the strength of the catheter and the thrust. Among the many microcatheters, this weaving or winding method can be roughly divided into four categories:
Braiding
Coil
Braiding + Coil (parallel)
Braiding + Coil (multi-layer)
The four options represent the requirements of different vascular lesions for the important performance of microcatheters. For example, in the design concept of braiding + coiling, the proximal braiding has good pushing ability and the distal coiling has good flexibility, which is a very good choice for neurovascular delivery. For CTO lesions, the high-hardness braiding can help it pass through calcification.
Among them, by adjusting the density and pitch of braiding or coiling, its pushing force and flexibility (bending resistance) can be changed accordingly.
In addition, there is currently a process for cutting metal tubes to achieve the performance of braiding or coiling springs.
The polymer material of the outer layer is also designed to meet the actual clinical needs. A series of materials with different hardness are used to conduct mechanical force from near to far.
