Association between iatrogenic atrial septal shunt VTI and clinical outcomes after mitral transcatheter edge-to-edge repair

Background Transseptal access during mitral transcatheter edge-to-edge repair (M-TEER) creates an iatrogenic atrial septal defect (iASD), but the prognostic significance of its flow remains uncertain. We evaluated intraprocedural net velocity-time integral (VTI) as a Doppler measure of directional iASD flow velocity, not shunt volume. Methods This retrospective single-center study included patients undergoing M-TEER between 2021–2023. Net Doppler VTI was calculated as left-to-right minus right-to-left VTI; the primary analysis included positive values. The primary outcome was all-cause mortality or heart-failure hospitalization at 6, 12, and 24 months. Results Among 160 patients, median net VTI was 27.75 cm (IQR, 20.2–40.0). Composite–event rates were 36.6%, 49.6%, and 61.4% at 6, 12, and 24 months, respectively. Adjusted analyses identified no statistically significant association of VTI with the composite outcome at 6 months (OR per 10-cm increase 0.99; 95% CI 0.81–1.21), 12 months (OR 1.01; 95% CI 0.83–1.22), or 24 months (OR, 1.09; 95% CI, 0.89–1.34). Findings were consistent across categorical, spline, and directional-component analyses, without an identified outcome-associated threshold. Baseline tricuspid regurgitation (TR) was available in 133 patients. Exploratory TR-VTI interaction analyses were not statistically significant at 6, 12, or 24 months ( P = 0.595, 0.691, and 0.669, respectively). Conclusions Among patients with predominantly left-to-right shunting after M-TEER, no statistically significant association was identified between intraprocedural net iASD VTI and mortality or heart-failure hospitalization overall.