An 86-year-old woman complained of gradually increasing dyspnoea (New York Heart Association stage III). Ten years previously she had surgical aortic valve replacement with a stented bioprosthesis (21 mm Carpentier-Edwards; Edwards Lifesciences, Irvine, CA, USA) for severe symptomatic aortic stenosis. At the same time, a triple coronary bypass graft was performed. Five years after surgery, a permanent pacemaker was implanted. Follow-up transthoracic echocardiography demonstrated severe stenosis of the aortic bioprosthesis (maximal pressure gradient 80 mmHg; aortic valve area 0.6 cm 2 ). Surgery was contraindicated (logistic EuroSCORE greater than 20%). The patient was referred to our centre for transcatheter aortic valve implantation (TAVI). Preimplantation multislice computed tomography (MSCT)-angiography confirmed the feasibility of the transfemoral approach, then a 23 mm Edwards SAPIEN XT bioprosthesis (Edwards Lifesciences) was successfully implanted from a right transfemoral approach. Immediate follow-up was unremarkable with no significant aortic regurgitation. Cardiac CT angiography (HD750 Discovery; General Electric, Milwaukee, USA) was performed 5 days after TAVI to evaluate the SAPIEN XT bioprosthesis positioning and deployment into the underlying Carpentier-Edwards bioprosthesis. The Edwards-SAPIEN XT bioprosthesis was precisely implanted at the basal level of the degenerative bioprosthesis ( Fig. 1 A and B). Circularity was good but, as expected, expansion of the SAPIEN XT was suboptimal at the basal level due to the 19 mm underlying stent (diameter 18.5 × 18.1 mm, measured surface 2.67 cm 2 , expected surface 4.15 cm 2 ) ( Fig. 1 C and D). By comparison, on the aortic side of the SAPIEN bioprosthesis, expansion was optimal ( Fig. 1 E and F; diameter 23.7 × 22.5 mm, measured surface 4.19 cm 2 ). Three-dimensional volume-rendering reconstructions accurately demonstrated the close link between the two stents ( Fig. 1 G and H).
