An improved indwelling catheter adapted for long-term usage includes a stable enzyme coating to prevent occlusion of the catheter lumen. The enzyme coating includes a fibrinolytic and/or lipolytic enzyme incorporated in a catheter coating to resist or control proteolytic degradation, thereby maintaining...http://www.google.ca/patents/US5538511?utm_source=gb-gplus-sharePatent US5538511 - Indwelling catheter with stable enzyme coating
