1. Stanford Center for Clinical Research (SCCR), Department of Medicine, School of Medicine, Stanford University, Stanford, CA, USA
2. Department of Cardiology and Angiology I, Faculty of Medicine, Heart Center, University of Freiburg, Freiburg, Germany
3. Quantitative Sciences Unit, Department of Medicine, School of Medicine, Stanford University, Stanford, CA, USA
4. Division of Nephrology, School of Medicine, Stanford University, Stanford, CA, USA
5. Division of Vascular Surgery, School of Medicine, Stanford University, Stanford, CA, USA
6. Division of Vascular Surgery, University of California at Davis, Sacramento, CA, USA