Abstract 4367980: Can IVUS Predict Aortic Remodeling? The Role of Flap Mobility in Type B Aortic Dissection With TEVAR

Background: The optimal timing of preemptive thoracic endovascular aortic repair (TEVAR) for type B aortic dissection (TBAD) remains controversial. In the chronic phase, favorable aortic remodeling is considered less likely. Previous studies suggest that the degree of intimal flap mobility may correlate with remodeling, possibly reflecting the extent of fibrosis within the intimal flap. We investigated whether higher intimal flap mobility, as assessed by intravascular ultrasound (IVUS), predicts aortic remodeling following TEVAR in TBAD. Methods: In this multicenter retrospective study, 79 patients who underwent TEVAR for TBAD using IVUS between April 2019 and December 2024 were evaluated. Aortic remodeling was defined as complete resolution of the false lumen (FL) in the descending thoracic aorta. The non-remodeling group included cases in which the FL persisted. IVUS was used to measure the maximum and minimum true lumen (TL) areas at the site of maximal flap mobility (Fig 1). Intimal flap mobility was quantified as the TL area increase rate (ΔTL%) = (max TL area – min TL area) / min TL area × 100. A Volcano Visions® PV.035 IVUS catheter was used for all measurements. Results: Of all patients, 61% achieved complete remodeling. Baseline characteristics, including age (55.2±11.4 vs. 58.8±12.5 years, p=0.336) were similar between groups. However, chronic kidney disease (CKD) was more prevalent in the non-remodeling group (13% vs. 55%, p=0.003), and the interval from TBAD onset to TEVAR was significantly shorter in the remodeling group (95±214 vs. 1244±1653 days, p=0.001). The ΔTL% was significantly higher in the remodeling group (87±68% vs. 34±45%, p=0.007). Multivariate analysis identified a ΔTL% >43% as an independent predictor of remodeling (OR 5.6, 95% CI 1.4–22.4, p=0.015), even after adjusting for CKD and timing of intervention. Receiver operating characteristic (ROC) curve analysis yielded an AUC of 0.79, with a 43% cut-off predicting remodeling with 75% sensitivity and 77% specificity. Conclusions: Intimal flap mobility, as assessed by TL area dynamics on IVUS, is an independent predictor of favorable aortic remodeling after TEVAR in TBAD. Preoperative evaluation of flap mobility may play a critical role in tailoring therapeutic strategies and timing, particularly during the chronic phase.