Weekly Journal Scan: transcatheter aortic valve implantation in patients with small aortic annulus

Key points• The SMall Annuli Randomized To Evolut or SAPIEN (SMART) Trial is a multi-centre, industry-funded, randomized controlled trial (RCT), aimed at evaluating the clinical outcomes and valve performance of a self-expanding supra-annular valve as compared with a balloon-expandable valve in patients with symptomatic severe aortic stenosis and small aortic annulus undergoing transcatheter aortic valve implantation (TAVI). 1 Patients with symptomatic severe aortic stenosis with an aortic valve annulus area of 430 mm 2 or less (as assessed by multi-detector computed tomography), and suitable anatomy for transfemoral TAVI, were randomized 1:1 to receive a self-expanding supra-annular valve (Evolut PRO/PRO+/FX; Medtronic) or a balloon-expandable valve (SAPIEN 3/3 Ultra; Edwards Lifesciences).The sponsor (Medtronic) contributed to the protocol development and was responsible for site selection, data monitoring, and statistical analyses.• The two co-primary endpoints, both of which were assessed through 12 months, were (i) a composite of death, disabling stroke, or rehospitalization for heart failure (tested for non-inferiority, with an 8% margin, under the assumption that an event would occur in 16% of the patients in each group), and (ii) bioprosthetic valve dysfunction (tested for superiority), a composite endpoint including haemodynamic structural valve dysfunction (defined as aortic valve mean gradient ≥ 20 mmHg); non-structural valve dysfunction [defined as a severe prosthesis-patient mismatch (i.e.indexed effective orifice area < 0.65 cm 2 /m 2 ) or at least moderate aortic regurgitation]; clinical valve thrombosis [defined according to Valve Academic Research Consortium (VARC)-2 criteria]; endocarditis (defined according to modified Duke criteria); or aortic valve re-intervention.Secondary endpoints included haemodynamic mean gradient, effective orifice area, haemodynamic structural valve dysfunction, bioprosthetic valve dysfunction in women (all assessed through 12 months), and moderate or severe prosthesis-patient mismatch at 30 days.• From April 2021 through September 2022, a total of 716 patients (mean age, 80 years; 87% women; self-expanding valve, n = 355; balloon-expandable valve, n = 361) were treated at 83 sites in Canada, Europe, Middle East, and the USA.The mean Society of Thoracic Surgeons Predicted Risk of Mortality was 3.3%.The mean (± standard deviation) aortic annulus area was 382 ± 34 mm 2 .The prevalence of bicuspid aortic valve was 4%.The first co-primary clinical endpoint occurred in 9.4% of patients in the self-expanding valve group and in 10.6% of those in the balloon-expandable valve group [difference -1.2%; 90% confidence interval (CI), -4.9 to 2.5, P < .001for non-inferiority; hazard ratio, 0.90; 95% CI, 0.56-1.43].The second co-primary endpoint (bioprosthetic valve dysfunction at 12 months) occurred in 9.4% of patients in the self-expanding valve group and in 41.6% of those in the balloon-expandable valve group (difference -32.2%; 95% CI, -38.7 to -25.6; P < .001for superiority).• The aortic valve mean gradient at 12 months was 8 mmHg in the self-expanding valve group vs. 16 mmHg in the balloon-expandable valve group, and the mean effective orifice area was 1.99 cm 2 in the self-expanding valve group vs. 1.50 cm 2 in the balloon-expandable valve group.As compared with the balloon-expandable valve group, the self-expanding valve group showed lower 12-month rates of haemodynamic structural valve dysfunction (3% vs. 32%), non-structural valve dysfunction (6% vs. 18%), bioprosthetic valve dysfunction in women (10% vs. 43%), and moderate or severe prosthesis-patient mismatch at 30 days (11% vs. 35%).Both groups showed low incidence of clinical valve thrombosis (0.3% vs. 0.3%), endocarditis (0.6% vs. 2.3%), and aortic valve re-intervention (0.9% vs. 0.6%).The rate of permanent pacemaker implantation at 30 days was 12% in the self-expanding valve group and 8% in the balloon-expandable valve group.