Prognostic value of aortic valve tissue composition assessed by pre-procedural CCTA in predicting in-hospital pacemaker implantation and clinical outcomes after TAVR

Abstract Background Aortic stenosis (AS) is driven by progressive fibrocalcific degeneration of the valve. While valvular calcium burden has established prognostic relevance in transcatheter aortic valve replacement (TAVR), the impact of non-calcific tissue components remains unclear. Contrast-enhanced Computed Tomography Angiography (CCTA), routinely performed for TAVR planning, uniquely enables noninvasive assessment of both calcific and non-calcific aortic valve (AV) tissue. (1) Advanced semi-automated quantification techniques now allow detailed characterization of leaflet composition, potentially enhancing risk stratification (2). Purpose To evaluate whether the burden of non-calcific AV tissue on pre-procedural CCTA predicts post-TAVR conduction disturbances, need for permanent pacemaker implantation, and in-hospital clinical outcomes according to Valve Academic Research Consortium-3 (VARC-3) criteria. Methods We retrospectively included 95 consecutive patients undergoing TAVR at our institution from January 2024 to December 2024 with available pre-procedural contrast-enhanced cardiac CTA. Using semi-automated software, we quantified calcific, non-calcific, and total AV tissue volumes. Pre-procedural clinical, echocardiographic, and demographic data were collected. The endpoints of the study included new conduction disturbances, in-hospital pacemaker implantation and VARC-3-defined clinical outcomes. Results A total of 95 patients were analyzed: 31 in the low-flow low-gradient (LF-LG) group and 64 in the high-gradient (HG) group. Compared to HG patients, LF-LG patients were more often female (67.7% vs. 42.2%, p = 0.02) with lower calcific aortic tissue (180 mm³ vs. 780 mm³, p = 0.004). The LF-LG group also exhibited a higher ratio of non-calcific to calcific tissue (4.68 vs. 2.73, p = 0.04). There were no statistically significant differences in procedural characteristics and in-hospital MACE according to VARC-3 criteria. Mortality was 0% in both groups. Multivariate logistic regression identified the non-calcific to calcific tissue ratio (OR = 1.41, 95% CI: 1.01–1.96, p = 0.043) and aortic valve calcium score (OR = 1.001, 95% CI: 1.000–1.002, p = 0.049) as independent predictors of pacemaker implantation. Other variables including gender, age, total aortic volume, and LVEF did not reach statistical significance in the model. Conclusion This study highlights the role of detailed quantification of non-calcific and calcific aortic valve tissue using CCTA in predicting post-TAVR conduction disturbances. Our findings show that calcium score and non-calcific/calcific ratio emerged as independent predictors on incidence of permanent pacemaker (PM) implantation. These results support the potential role of preprocedural CCTA-derived tissue characterization as a useful tool for patient risk stratification and procedural planning in TAVR candidates.Graphical Abstract