Patent attributes
A catheter is provided which includes an outer catheter and an extendable inner catheter. A sealing feature is positioned between the inner catheter and the outer catheter to seal the annular gap between the two while allowing axial translation. The seal may be a compliant protrusion surrounding the inner catheter and may have a chevron-shape for facilitating axial translation. The seal may be a one-way valve configured to allow antegrade flushing but prevent retrograde flow. The seal may be squeegee-like flange on the distal tip of the outer catheter. The seal may be an expandable bulge, which may be mechanically expandable or inflatable or which may be a photosensitive or electrosensitive hydrogel. The seal may include a spring that is radially compressed upon translation or rotation of the inner catheter to transiently break the seal. Also provided is a seal for sealing between the catheter and the vasculature.