['Postoperative development of aortic insufficiency (AI) after implantation of left ventricular assist devices (LVADs) has recently been recognized, but the devices in the previous reports have been limited to the HeartMate I or II. The purposes of this study were to determine whether AI develops with other types of LVADs and to elucidate the factors associated with the development of AI.', 'Thirty-seven patients receiving LVADs without evident abnormalities in native aortic valves were enrolled (pulsatile flow LVAD [TOYOBO]: 76%, continuous flow LVAD [EVAHEART, DuraHeart, Jarvik2000, HeartMate II]: 24%). Frequency of aortic valve opening and grade of AI were evaluated by the most recent echocardiography during LVAD support. None of the patients had more than trace AI preoperatively. During LVAD support AI >- grade 2 developed in 9 patients (24%) across all 5 types of devices. More severe grade of AI correlated with higher plasma B-type natriuretic peptide concentration (r = 0.53, P < 0.01) and with less frequent of the aortic valve (r = 0.45, P < 0.01). Multivariate analysis revealed that lower preoperative left ventricular ejection fraction and a continuous flow device type were independent risk factors for higher incidence of AI.'] Are less frequent opening of the aortic valve and a continuous flow pump risk factors for postoperative onset of aortic insufficiency in patients with a left ventricular assist device?