Transcatheter aortic valve replacement in the treatment of bicuspid aortic stenosis with "down-size" interventional valves: procedural and mid-term follow-up

Background: Due to the influence of anatomical structure, replacing the bicuspid valve using transcatheter aortic valve replacement (TAVR) would increase the risk of perivalvular leakage and conduction block, affecting the hemodynamic effect of the interventional valve. In this study, for bicuspid and tricuspid valves, we implemented different valve selection strategies to explore the safety and effectiveness of TAVR in the treatment of bicuspid aortic stenosis with "down-size" interventional valves using the VenusA-valve system. Methods: The operation was performed with the VenusA-valve via transfemoral approach. The selected valves were appropriately sized based on the results of transthoracic echocardiography (TTE), contrast-enhanced computed tomography (CT), and the morphology of intraoperative pre-dilation balloons. For tricuspid valve cases, the VenusA valve is usually larger than the annulus diameter, whereas the "down-size" approach was adopted for bicuspid aortic valve (BAV) cases. The shape of the pre-dilation balloon allowed further sizing of the annulus diameter by the degree of lumbar constriction of the balloon, aiding in intervention valve size selection, particularly in cases of BAVs. Results: A total of 65 patients underwent TAVR for aortic stenosis with VenusA-valve systems. Of these, 29 cases had a BAV and 36 cases had a tricuspid aortic valve (TAV). The distribution of VenusA-valve sizes differed between TAV and BAV cases (P=0.007). Furthermore, there was a significant decrease in the average mean gradient in TAV patients from 54.7 to 12.2 mmHg (P<0.001), and in BAV patients from 61.6 to 14.3 mmHg (P<0.001). The percentage of paravalvular leakage greater than mild was 6.90% in the BAVs and 5.56% in the TAVs at procedural outcomes (P=0.955). The mean follow-up period was 22.23 months (range, 12 to 39 months). The proportion of New York Heart Association (NYHA) class III/IV decreased from 78.5% preoperatively to 11.3% at the last follow-up (P<0.001). A total of 27 patients with TAV and 19 patients with BAV underwent TTE at 1-year follow-up after operation. There was no significant contrast in the average pressure difference between TAVs and BAVs at 1-year follow-up (11.9 vs. 14.3 mmHg, P=0.18). Conclusions: The VenusA-valve for TAVR produced positive clinical outcomes and valve functionality in both BAVs and TAVs. In the case of BAVs, selecting a smaller interventional valve size was deemed viable.