Accuracy of Virtual Circle Method and Valve-to-Aorta Distance Change After Redo-TAVR: Multicenter Paired CT Analysis

BACKGROUND: The virtual circle method is currently used in preprocedural computed tomography planning for Redo-transcatheter aortic valve (TAV) replacement to simulate the predicted outer boundary of the index TAV and the valve-to-aorta distance for coronary risk assessment, yet its accuracy against postprocedural observations has not been evaluated. This study aimed to assess the accuracy of the virtual circle method in predicting index TAV expansion and coronary risk following a second TAV implantation using paired preprocedural and postprocedural computed tomography in patients undergoing Redo-TAV replacement. METHODS: This multicenter retrospective study included 58 patients who underwent Redo-TAV replacement at 5 sites with paired preprocedural and postprocedural cardiac computed tomography. Three valve combinations were analyzed: Evolut-in-SAPIEN (n=17), SAPIEN-in-SAPIEN (n=13), and SAPIEN-in-Evolut (n=28). Index TAV frame expansion was quantified by area- or perimeter-derived diameter change. Accuracy of the virtual circle method was defined as a diameter difference within ±1 mm between predicted and observed index TAV frame diameter. RESULTS: In the Evolut-in-SAPIEN combination, meaningful index SAPIEN frame expansion occurred only with effective pre/postdilatation, whereas in both the SAPIEN-in-SAPIEN and SAPIEN-in-Evolut combinations, consistent frame expansion was observed regardless of dilatation. Changes in index frame diameter corresponded inversely to changes in valve-to-aorta distance. In the SAPIEN-in-Evolut combination, expansion was governed chiefly by implant position and sizing strategy. Across all combinations in which the virtual circle method was applicable (n=53), accurate prediction was achieved in 31 patients (58.5%), with overestimation in 14 (26.4%) and underestimation in 8 (15.1%). CONCLUSIONS: The virtual circle method provided an accurate or conservative (overestimating) estimate of index TAV expansion and coronary risk in the majority of patients (85%), supporting its clinical utility for Redo-TAVR planning. The remaining 15% showed underestimation of modest magnitude (median, 1.3 mm), occurring predominantly in patients who underwent predilatation and postdilatation, warranting heightened caution in borderline coronary anatomy when dilatation strategies are employed.