1. Department of Medicine and
2. Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
3. Department of Medicine, University of Colorado, Denver, Colorado
4. Department of Pediatrics, Columbia University, New York, New York
5. Department of Medicine, Mayo Clinic, Jacksonville, Florida
6. Department of Medicine, Washington University, St. Louis, Missouri
7. Department of Medicine, University of California San Francisco, San Francisco, California
8. Arizona Pulmonary Specialists, Phoenix, Arizona
9. Department of Medicine, Vanderbilt University Medical Centre, Nashville, Tennessee
10. Department of Medicine, Weill Cornell Medicine, New York, New York
11. Department of Medicine, Louisiana State University, New Orleans, Louisiana
12. Department of Medicine, Johns Hopkins University, Baltimore, Maryland
13. Kentuckiana Pulmonary Associates, Louisville, Kentucky
14. Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin
15. The Oregon Clinic, Portland, Oregon
16. Cottage Health Pulmonary Hypertension Centre, Santa Barbara, California
17. Advanced Lung Disease and Transplant Program, Inova Fairfax Hospital, Falls Church, Virginia
18. Department of Medicine, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
19. Department of Medicine, University of Minnesota, Minneapolis, Minnesota; and
20. Department of Medicine, Alpert Medical School of Brown University, Providence, Rhode Island