Fletcher, Miller

Introduction: Acceleration time (AT) and Doppler Velocity Index (DVI) are critical parameters in assessment of bioprosthetic aortic valve dysfunction (BAVD). AT>100ms and DVI < 0.25 are highly suggestive of prosthetic obstruction and are incorporated in all triage algorithms. Little is known about their relationship with flow. Hypothesis: AT and DVI may be affected by transprosthetic flow in patients with significant bioprosthetic aortic valve dysfunction (BAVD). Methods: Single center, retrospective analysis of patients with severe BAVD (confirmed at surgical re-replacement, transcatheter valve-in-valve implantation, or successfully treated bioprosthetic valve thrombosis). Standard prosthetic parameters (AT, DVI, effective orifice area (EOA), mean gradient, presence and degree of regurgitation), flow (stroke volume index, Svi; transprosthetic flow rate, FR) were measured on the transthoracic echocardiogram at the time of diagnosis with severe BAVD. Results: A total of 266 patients with severe BAVD underwent treatment between 2008-2020. BAVD mechanism was obstruction (N=192, 72%), regurgitation (n=48, 18%) mixed stenosis and regurgitation (n=15, 6%) and patient-prosthetic mismatch (n=12, 5%). DVI was moderately correlated with FR (r=0.50, p<0.001); AT had a weak but significant inverse correlation with FR (r=0.24, p<0.001). SVi had a weaker influence on DVI (r=0.35, p<0.001) and no correlation with AT. Conclusions: AT and DVI are influenced by transprosthetic flow rate. This flow-dependency should be considered when assessing the mechanism of BAVD.