Proof of Concept: Echo Compatible Mock-Circulatory Flow Loop to Accurately Quantify Aortic Regurgitation in Patients with Left Ventricular Assist Devices

Abstract

Aortic regurgitation (AR) in patients with Left ventricular assist devices (LVAD) is associated with poor outcome and decreased device durability. Accurate quantification of aortic regurgitation in patients with LVAD by echocardiography has been a challenge, particularly since there is no gold standard for accurate regurgitant volume estimation. Therefore, the aim of our study was to develop a mock-circulatory flow loop using patient specific 3D model that allows accurate assessment of AR by flow meters. Using a cardiac CT from a patient with LVAD and aortic regurgitation, a 3D model was printed. A pulsatile flow loop system and HeartMate II LVAD was connected to 3D model and we were able to accurately simulate LV and Aortic pressure (figure 1). Aortic regurgitant volume (RV) was quantified at various LVAD speeds. The AR volume was quantified at increments of 200 RPM. At baseline speed of 8000 RPM, the regurgitant volume was 34 cc and with each increment in speed the RV increased proportionally. This system is echo compatible and the in vitro echocardiographic evaluation of AR severity is being developed CONCLUSION: We have created patient specific model of AR in a flow system with LVAD support. Thus far we have demonstrated that RV varies directly with level of LVAD support.