Impact of false lumen occluders on aortic remodeling after endovascular repair of chronic type B dissection.

OBJECTIVE: To evaluate morphological and clinical outcomes after false lumen occluder (FLO) implantation for postdissection thoracoabdominal aortic aneurysm and to investigate the impact of adjunctive false lumen embolization on aortic remodeling.

METHODS: A retrospective single-center study included 71 patients (median age, 64 years; interquartile range, 58-70 years; 77.5% male) with chronic type B aortic dissection treated between June 2018 and December 2024 with third-generation FLO implantation during thoracic endovascular aortic repair (TEVAR) or fenestrated/branched repair. Aortic, true lumen (TL), and false lumen (FL) volumes were quantified using three-dimensional reconstructions on Aquarius software. FLO remodeling was defined as compression of the occluder with a crescent shape on follow-up imaging. Aortic remodeling (FL regression) was defined as a ≥10% reduction in FL volume, stability as ±10% change, and enlargement as >10% increase compared with baseline. Associations between clinical, anatomical, and procedural variables and remodeling outcomes were analyzed using nonparametric and mixed effects models.

RESULTS: Across 268 imaging examinations, total aortic and FL volumes decreased significantly over time, whereas the TL volume expanded (all P < .001). The median total aortic volume declined from 796 cm3 at 1 month to 706 cm3 at 4 years, and the FL volume decreased from 501 cm3 to 296 cm3, whereas TL volume increased from 287.5 cm3 to 358 cm3. Median follow-up was 13.3 months (interquartile range, 5.6-36.5 months). Aortic remodeling occurred in 83.1% of patients, FL stability in 12.7%, and enlargement in 4.2%. Regression was more frequent in younger patients (P = .048) and those with smaller baseline diameters and volumes (P = .043 and P = .034). Adjunctive embolization was strongly associated with TL expansion (χ2 = 5.8; P = .016) and FLO remodeling (χ2 = 5.2; P = .022), and showed a trend toward increased aortic remodeling (χ2 = 4.8; P = .056) without added mortality or morbidity. No cases of spinal cord ischemia occurred. FLO size (≥40 mm vs <40 mm) and position (thoracic, diaphragmatic, or abdominal) did not influence outcomes. FLO remodeling was strongly correlated with concurrent FL reduction (χ2 = 20.8; P < .001) and may represent a radiologic marker of procedural success.

CONCLUSIONS: FLO implantation provided durable aortic remodeling in chronic type B aortic dissection, and adjunctive embolization enhanced remodeling efficacy by eliminating residual perfusion without increasing risk. The absence of spinal cord ischemia and the identification of FLO remodeling as a surrogate of success highlight the value of this combined, low-risk strategy for long-term aortic stability.