ABS 111: Calcium and Thrombus Volume Analysis of Patients: Using Pre and Post-TAVR Scans

Aditi Bang ¹ , Sanchita Bhat, PhD ¹ , Lakshmi Dasi, PhD ¹

¹ Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia

Van Wickle (2025) Volume 1, ABS 111

Introduction: Aortic stenosis, primarily caused by calcific degeneration of the aortic valve, affects over 20% of older Americans and can severely restrict blood flow from the heart. Transcatheter Aortic Valve Replacement (TAVR) offers a minimally invasive solution for patients deemed high-risk for open-heart surgery. However, complications such as hypoattenuated leaflet thickening (HALT) and subsequent thrombus (blood clot) formation can compromise the durability and hemodynamic performance of the implanted valves. Understanding how valve design, calcification, and clot formation interact is essential for improving patient outcomes.
This study investigates two critical aspects of TAVR outcomes: (1) thrombus formation post-TAVR and (2) pre-TAVR calcium burden. Using pre- and post-TAVR cardiac CT scans, we applied advanced 3D Slicer segmentation techniques to isolate and quantify calcium in preoperative scans and thrombus volume in postoperative scans. Initial results indicate that thrombus tends to form near the base of the aortic valve, particularly in regions with flow stagnation. Regional distribution of clots and variation by valve type suggest design-specific susceptibility. Additionally, patients with higher preoperative calcium burden demonstrated greater challenges in valve deployment, reinforcing the need for personalized risk assessment. The ultimate goal is to enhance procedural success, reduce post-operative complications, and extend valve durability for patients undergoing TAVR.

Methods: Pre- and post-TAVR cardiac CT scans were obtained from patients who underwent valve replacement procedures. To analyze post-procedural thrombus, the 3D Slicer software platform was used to segment the implanted valve and isolate thrombus formations near the leaflets. Advanced segmentation tools enabled precise extraction and volumetric quantification of blood clots across different valve types, allowing for comparison between balloon-expandable and self-expandable designs. For calcium analysis, pre-TAVR scans were processed using similar 3D Slicer techniques to segment and quantify calcific deposits within the native aortic valve. Segmented calcium volumes were compiled and analyzed to determine correlations between preoperative calcification and procedural outcomes.

Results: We found that self-expandable valves exhibited a higher thrombus volume near the aortic leaflet base compared to balloon-expandable valves, suggesting valve design influences clot formation. Additionally, patients with greater preoperative calcium burden experienced more irregular valve expansion, potentially increasing their risk for post-TAVR complications. These findings support the hypothesis that both valve structure and calcification patterns significantly impact long-term TAVR outcomes. Quantitative analysis confirmed that higher calcium volumes pre-TAVR correlated with regions of post-TAVR thrombus formation, highlighting the need for improved patient-specific planning and structural refinements in future valve designs.

Discussion: Our findings emphasize the critical role of valve design and preoperative calcium burden in influencing post-TAVR thrombus formation. By demonstrating that self-expandable valves may predispose patients to higher clot volumes, this study supports the need for structural redesigns that minimize flow stagnation. Additionally, calcium quantification could serve as a valuable tool in pre-procedural risk stratification. Incorporating these imaging-based metrics into clinical decision-making may improve long-term valve performance and patient outcomes. Future work will focus on expanding the patient dataset and integrating machine learning models to enhance predictive accuracy for post-TAVR complications.