1. University of Texas Southwestern Medical Center Dallas TX
2. Providence Spokane Heart Institute Spokane WA
3. Michael E. Debakey Veteran Affairs Medical Center Houston TX
4. Baylor College of Medicine Houston TX
5. Labcorp Morrisville NC
6. University of Groningen and University Medical Center Groningen Groningen The Netherlands
7. Feinberg School of Medicine Northwestern University Chicago IL