Estimation of the Severity of Aortic Insufficiency by HVAD Flow Waveform

Purpose: Aortic insufficiency (AI) significantly affects morbidity and mortality in patients with left ventricular assist devices. Although AI may be commonly assessed by echocardiography, expert techniques are required for accurate quantification of AI severity. Description: In this prospective blinded study, screenshots from the HVAD (Medtronic, Framingham, MA) display and simultaneous echocardiographic measurements were obtained. Each screenshot was digitized and the early diastolic phase slope was calculated, with blinding to the echocardiographic results. The regurgitant fraction of AI was quantified by Doppler echocardiography of the outflow graft. Evaluation: A total of 30 patients (median, 57 years old; 57% male) were enrolled. A cutoff of −17.6 L/min/s for the early diastolic phase slope had a sensitivity of 0.92 and a specificity of 0.53 to estimate significant AI with a regurgitant fraction of 30% or greater, and it significantly stratified patients into a low regurgitant faction group (0.3%) and a high regurgitant fraction group (33.0%) (P =.009). The early diastolic phase slope had a moderate correlation with the actually measured regurgitant fraction (r =.50). Conclusions: The early diastolic phase slope of the HVAD flow waveform may be a parameter that can estimate the presence of clinically significant AI.