Risk of Aortic Root Rupture in Bicuspid Aortic Stenosis: The ABC Sizing Algorithm for SAPIEN 3 Valves

BACKGROUND: This study evaluated the ability of the ABC Bicuspid Sizing Algorithm to predict aortic root rupture in patients treated with transcatheter aortic valve replacement using SAPIEN 3 valves. METHODS: We conducted a retrospective multicenter study among 15 centers in 7 countries of aortic root rupture cases and controls without root complications. Computed tomography analysis was performed blinded to rupture status. The ABC algorithm was applied to classify risk (high-risk criteria): (1) annular oversizing >10%, (2) intercommissural distance − valve diameter ≤1 mm, (3) maximum sinus diameter − valve diameter <6 mm alone, or (4) maximum sinus diameter − valve diameter 6 to 8 mm with contrast calcium volume >1000 mm 3 and raphe + contralateral or ipsilateral leaflet calcium volume >800 mm 3 , (5) protruding nodular intercommissural distance calcium or full-length calcification of both leaflet edges. RESULTS: A total of 170 patients were included (23 ruptures and 147 controls). Cases exhibited higher total calcium volume (median: 1498 mm 3 versus 826 mm 3 ; P <0.001), smaller intercommissural distance difference (median: −0.15 versus 1.19 mm; P =0.009), smaller maximum sinus difference (median: 6.79 versus 9.19 mm; P <0.001), and greater annular oversizing (median: 6.57% versus 3.51%; P =0.047). The presence of any high-risk criterion had a sensitivity of 100% (95% CI, 85.7%–100%) and a specificity of 89.1% (95% CI, 83.1%–93.2%) for the identification of rupture cases. The diagnostic odds ratio was 374.5 (95% CI, 21.7–6459.9), with a positive likelihood ratio of 9.19 and a negative likelihood ratio of 0.023. CONCLUSIONS: High calcium volume, narrow sinus dimensions, and excessive valve oversizing were associated with aortic root rupture. The ABC algorithm showed promising performance for risk stratification of patients with bicuspid anatomy being considered for treatment with a SAPIEN 3 valve.