Issued Patents All Time
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4759759 | Bubble heart valve | David K. Walker, Richard T. Brownlee, Denton E. Hewgill, Roberto Racca | 1988-07-26 |
| 4340977 | Catenary mitral valve replacement | Richard T. Brownlee, David K. Walker | 1982-07-27 |