Abstract
A published balloon-based percutaneous temporary aortic valve (TAV), with a specific fixed gap-to-aorta cross-sectional area ratio, was shown to provide haemodynamic support in acute aortic regurgitation (AR). The fixed gap of the balloon-TAV, however, limits the ability to optimize the gap size balancing coronary flow vs AR protection. Hence, a reduced diastolic gap may improve AR protection, but could reduce coronary flow and increase systolic TAV flow resistance. A new membrane-based TAV, which avoids these design limitations, could guide gap size optimization and advance the development into a pre-clinical tool. The re-designed TAV prototype has a membrane-cone collapsible in systole to reduce flow resistance and expands in diastole with a gap-to-aorta cross-sectional area ratio that can be tailored to optimize AR protection and coronary flow. Without the concern for systolic TAV flow resistance, a lower limit of the gap:aorta cross-sectional area ratio could be determined. The ability of the membrane-TAV design in determining an optimal gap:aorta ratio is tested in an in vitro flow chamber. Three prototypes with reducing gap:aorta cross-sectional area ratios (35%, 15%, 0%) were tested in a flow chamber of simulated acute severe AR. Correspondingly, increasing in forward cardiac output volumes, coronary flow:aortic regurgitant volume ratios and reduction in aortic regurgitant volumes were observed (p < 0.001) in the three models. The membrane-TAV concept contains a design feature for optimization of LV protection from acute AR and coronary perfusion by defining an optimal gap:aorta ratio. Along with the results from the balloon-TAV, a clinically useful percutaneous device for the management of acute severe aortic regurgitation is becoming possible.
Declaration of interest
The author reports no conflicts of interest. The author alone is responsible for the content and writing of the paper.