1. Veterans Affairs North Texas Health Care System Dallas TX
2. University of Texas Southwestern Medical Center Dallas TX
3. Cardiac‐Thoracic‐Vascular Department University of Padua Italy
4. Oklahoma Heart Hospital Oklahoma City OK
5. Georgetown University Hospital Washington DC
6. University of Louisville School of Public Health and Information Sciences Louisville KY
7. Valve Science Center Minneapolis Heart Institute Foundation Abbott Northwestern Hospital Minneapolis MN
8. Harrington Heart and Vascular Institute University Hospitals of Cleveland Case Western Reserve University School of Medicine Cleveland OH
9. Minneapolis Heart Institute Foundation Minneapolis MN