1. American College of Cardiology; American Heart Association Task Force on Practice Guidelines (Writing Committee to revise the 1998 guidelines for the management of patients with valvular heart disease), Society of Cardiovascular Anesthesiologists, Bonow RO, Carabello BA, Chatterjee K, de Leon AC Jr, Faxon DP, Freed MD et al (2006) ACC/AHA 2006 guidelines for the management of patients with valvular heart disease. Circulation 114(5):e84–e231
2. Albert A, Florath I, Rosendahl U, Hassanein W, Hodenberg EV, Bauer S et al (2007) Effect of surgeon on transprosthetic gradients after aortic valve replacement with Freestyle stentless bioprosthesis and its consequences: A follow-up study in 587 patients. J Cardiothorac Surg 2:40
3. Ali A, Halstead JC, Cafferty F, Sharples L, Rose F, Goulden R et al (2006) Are stentless valves superior to modern stented valves? A prospective randomized trial. Circulation 114(1 Suppl):I535–I540
4. Bach DS, Lemire MS, Eberhart D, Armstrong WF, Deeb GM (2000) Impact of high transvalvular velocities early after implantation of Freestyle stentless aortic bioprosthesis. J Heart Valve Dis 9:536–543
5. Bach DS, Cartier PA, Kon N, Johnson KG, Dumesnil JG, Doty DB (2001) Impact of high transvalvular to subvalvular velocity ratio early after aortic valve replacement with Freestyle stentless aortic bioprosthesis. Sem Thorac Cardiovasc Surg 13(4):75–81