1. Non-Invasive Vascular Laboratory, Cleveland Clinic Heart and Vascular Institute, Cleveland, Ohio.
2. Department of Cardiovascular Medicine, Cleveland Clinic Heart and Vascular Institute, Cleveland, Ohio.
3. Department of Vascular Surgery, Cleveland Clinic Heart and Vascular Institute, Cleveland, Ohio.
4. Department of Thoracic and Cardiovascular Surgery, Cleveland Clinic Heart and Vascular Institute, Cleveland, Ohio.