Randomized prospective multi-center imaging study which investigates the impact of different immunosuppressive protocols (Everolimus (Certican®) or Mycophenolate mofetil (CellCept®)) on cardiac allograft vasculopathy (CAV) in heart transplanted patients. Maximal intima-thickness will be visualized by optical coherence tomography (OCT) to assess the progression of CAV.