Abstract 17083: Aortic Luminal Contrast Attenuation Varies With Dissection Morphology and is Associated With Need For Intervention

Abstract

Introduction: Prognostication after acute Type B aortic dissection (aTBAD) may be limited when relying upon static computed tomographic angiography (CTA) images to evaluate a dynamic process. We performed an exploratory study to characterize variations in luminal contrast attenuation on CTA, as a surrogate for blood flow in dissection, and to determine whether the resulting parameters held prognostic value. Methods: Retrospective, single-institution data for patients with aTBAD were gathered from 1999-2020. Patients with prior dissection repairs were excluded. Dissection morphology was classified by the SVS/STS scheme and location/number of fenestrations. Hounsfield unit ratios (HUR) comparing lumina, phases, and aortic zone were calculated. Aortic growth, false lumen thrombosis, and need for intervention were evaluated with univariable logistic regression. Results: After exclusions, 85 patients were identified (mean age 61.9 years, 69.4% male). SVS/STS B 3,10 (20%) and B 3,5 (12.9%) predominated (Figure). Most fenestrations were in Zone 4/5 (56.5%) and associated with more equilibrated HUR (0.93) compared to dissections without fenestration (0.70, p = 0.04). Fenestration zone was not associated with HUR ( p = 0.59). Intervention occurred in 65.9%, most often for aneurysmal degeneration (43.8%), followed by visceral/limb ischemia (32.6%). Growth occurred in 28.2%. Increased arterial false-to-true HUR was strongly associated with eventual need for intervention (OR 25.3 [95% CI 4.15-188.4], p = 0.001) while increased delayed-to-arterial false lumen HUR was associated with decreased intervention (OR 0.49 [95% CI 0.25-0.89], p = 0.02). Conclusion: In patients with aTBAD, calculated permutations of HUR across lumina and between CTA phases may give insight into blood flow dynamics, which in turn likely impact need for intervention. Future prospective studies of time-resolved CTA are likely to hold significant prognostic value and alter management.