Development of a Novel Holistic Assessment Strategy of TAVI-Induced Flow Restoration via Dimensionality Reduction Techniques

Abstract

Purpose Restoration of physiological aortic hemodynamics is a crucial therapeutic target after transcatheter aortic valve implantation (TAVI). However, quantifying this restoration is challenging, particularly using conventional markers. This study presents a novel, unsupervised approach based on proper orthogonal decomposition (POD), suitable for holistic characterization of patient-specific aortic flow field and their association with procedural outcome. Material and Methods Patients (n = 8) with severe aortic valve stenosis (AS) undergoing TAVI were studied. Three metrics were evaluated: patient-specific composite cardiovascular stress signature, pre-procedural free hemoglobin levels and degree of flow restoration. Flow restoration was quantified using POD-based similarity measures (Euclidean distances and Dynamic Time Warping), and compared with conventional hemodynamic markers, i.e. shear stresses, helicity and turbulence production. Unsupervised clustering was applied to explore agreement with biochemical patterns and clinical outcomes. Results POD identified coherent flow structures and enabled quantification of restoration relative to healthy references. POD-based markers provided more clinically interpretable groupings than conventional measures in this cohort. Patients with low restoration exhibited more pathological composite cardiovascular stress signatures and adverse outcomes during short-term follow-up. Conclusion POD-based flow analysis provides a holistic and interpretable quantification of post-TAVI aortic hemodynamics. In the given cohort, the method showed agreement with biochemical patterns and clinical outcomes, highlighting its potential to complement conventional hemodynamic and procedural assessment.

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