The prevalence and clinical significance of AI in pts on continuous flow LVAD support is controversial. Previous reports indicate that 25% of pts develop mild-to-moderate AI within 1 year of CF-LVAD support. We examined the prevalence of at least moderate de novo AI and clinical outcomes of pts who developed it.Baseline and post-implant echocardiograms and clinical records of all pts at our institution who received a HMII were reviewed. Pts were excluded if they had mild or more AI at baseline or if they had an aortic valve manipulation prior to or at time of LVAD implantation.158 pts were included. Mean age was 55 ± 14 years, 77.8% were male, and 81.6% had LVAD implantation as BTT. 15 (9.5%) pts developed at least moderate AI (moderate: 13 [8.2%], severe: 2 [1.3%]) with a mean follow-up time of 347 ± 356 days. Freedom from moderate AI or greater at 1 and 2 years was 88% and 65% respectively. After the development of at least moderate AI, 9/15 pts (60.0%) underwent HTX, including 2 (13.3%) who were upgraded to UNOS 1A for symptomatic moderate/severe AI. 1 other pt (6.7%) developed symptomatic AI and required AV repair. 1 pt (6.7%) underwent device exchange for suspected device thrombosis with concurrent AV repair. 5 (33.3%) remain on device support at a mean support time of 983 ± 551 days without evidence of heart failure or need for surgical AV intervention.Clinically significant AI may complicate long term CF-LVAD support. Although the absolute number of patients requiring surgical correction of AI is currently small, prevention and treatment strategies should be developed as the number of patients on long term support is rapidly increasing. [figure 1]