[1] Univ Dusseldorf, Fac Med, Dept Cardiovasc Surg, Dusseldorf, Germany
[2] Univ Dusseldorf, Fac Med, Dept Diagnost & Intervent Radiol, Dusseldorf, Germany
[3] Univ Dusseldorf, Fac Med, Dept Cardiol, Dusseldorf, Germany
[4] City Univ London, Sch Engn & Math Sci, Bioengn Dept, London EC1V 0HB, England