A medical device-includes a scaffold crimped to a catheter having an expansion balloon. The scaffold is crimped to the balloon by a process that includes one or more balloon pressurization steps. The balloon pressurization steps are selected to enhance scaffold retention to the balloon while retaining, at least partially, the original balloon folds as the balloon is pressurized and de-pressurized within a crimper head. By at least partially retaining the original balloon folds, a uniformity of scaffold expansion by the balloon is improved.