Comparison of the feasibility and results of the following frailty assessment tools in advanced heart failure patients treated with ventricular assist device Implantation or awaiting heart transplantation in Eurotransplant-Status "high urgency":
* Evaluation of the muscle mass in the preoperative CT-Scan
* Bioelectrical Impedance Analysis
* 6 Minute Walk Test
* Grip Strength Measurement
* Questionnaires: EQ5D-5L, Rockwood Frailty Scale
The assessment will be conducted prior to surgery, after surgery and at 6 Month Follow-up
