1. Department of Surgery, University of California Davis, 2335 Stockton Blvd, 5th floor, Sacramento CA 95817, USA
2. Department of Cardiothoracic Surgery, David Grant USAF Medical Center, 101 Bolin Circle, Travis AFB, CA 95433, USA
3. Norman M. Rich Department of Surgery, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road Bethesda, Bethesda, MD 20814, USA