1. VAD Design Consideration 1. FIT OF THE SYSTEM Decide who the device intended for. Device fit in patient. Cause minimal or no pathologic conditions. Consider volume, mass, dimension, location of tubes, conduits, connectors. Physical attributes – hard, soft, smooth, rough, sharp corners damage tissues. Should not project heat. Effect of device movement and vibration. Acceptable sound levels at various frequencies. Meet EM interference, susceptibility standard.

2. VAD Design Consideration 2. PUMP PERFORMANCE Performance specified in cardiac output range. Cardiac output performance obtained at physiologic pressure (left atrial pressure ~7mmHg, aortic pressure~100mmHg etc). Control of device must be included. Device must respond to patient’s cardiac output requirement. 3. BIOCOMPATIBILITY Device must not cause excessive damage to biologic system. Minimally thrombogenic and minimally hemolytic. Minimal effect on immune system. Should not promote infection, calcification, tissue necrosis.

3. VAD Design Consideration 4. RELIABILITY Design specification must have : Target reliability for device (e.g 80% confidence for 2 yrs) Clarification on components that could be changed if necessary Deal with any service that device may require. Example : device design life is 5 yrs but battery replacement at 2 yrs interval is allowed 5. QUALITY OF LIFE Designer must specify what is a satisfactory quality of life. Quality of life must be considered in relation to patient’s quality of life without the device. How much weight older patient can carry? How often power source required to recharge? What sound level is acceptable?