Expandable and collapsible medical device

摘要

A catheter (or cannula) is small enough in diameter to be placed minimally invasively into the body of a patient but also can be expanded post-placement to provide a larger-diameter placed catheter that supports fluid flow at a rate higher than is possible through the pre-placement reduced-diameter catheter. The expandable catheter is constructed using one or more shape memory polymers and can include one or more stent-like sections and/or at least part of the cannula formed as folded lobes. Each of the stent-like sections is configured to enhance the flexibility of the section as compared to the other parts of the catheter and thus allow the section to accommodate tight bends and turns when inserted into the body of the patient. The folded lobes are axial folds that constitute at least one section of the cannula, and they unfold upon expansion of the catheter to create a large cross-sectional shape.