Increased Radial Force Improves Stent Deployment in Tricuspid but Not in Bicuspid Stenotic Native Aortic Valves

Background. Stent deployment within stenotic native aortic valves has been shown to depend on valve anatomy (presence of bicuspid valve or not). This study investigated the influence of stent stiffness on stent expansion. Methods. The study included 88 patients with severe aortic stenosis, and 36 (41%) had bicuspid aortic valves. Two self-expandable stents with different radial force were deployed intraoperatively inside stenotic aortic valves before surgical aortic valve replacement. Patients in group B received a stent stiffer than that in group A. Effect of stent radial force on stent shape and incidence of paraprosthetic gaps was determined. Results. Noncircular stent deployment was more frequent in bicuspid (81%) than in tricuspid aortic valves (33%; p < 0.0001). Increasing stent radial force significantly improved stent shape in tricuspid valves (circular shape: 60% in group A vs 93% in group B; p = 0.005) but had no significant effect in bicuspid valves (12.5% in group A vs 27% in group B; p = 0.394). Likewise, incidence of paraprosthetic gaps was significantly reduced with the stiff stent in tricuspid valves (64% in group A vs 30% in group B, p = 0.025) but not in bicuspid valves (50% in group A vs 60% in group B; p = 0.722). Conclusions. Increased stent radial force had a favorable effect on stent deployment in tricuspid but not in bicuspid valves. In bicuspid valves, stent maldeployment was constant. Leaflet distortion of implanted valved stent might be a concern in this setting.