With respect to LVAD efficacy, patients have been supported for periods as long as 344 days on the pneumatic system and 503 days with the electromechanical device. Experience with the TCI pneumatic system in 75 LVAD patients show improved one year survival after transplantation in the LVAD patients as opposed to patients who did not receive the LVAD despite the same selection criteria. Experience with the vented electric LVADs in bridge patients show a transplant and survival rate that is similar to the pneumatic device. LVADs have also been shown to have a favorable effect on circulatory hemodynamics and exercise capacity. Among 53 patients who survived the TCI LVAD procedure, 90 percent improved to New York Heart Association (NYHA) functional class I and 10 percent to functional class II.