Abstract 118: Use of Computational Fluid Dynamics Studies in Predicting Aneurysmal Degeneration of Acute Type B Aortic Dissections

Abstract

Objectives: While uncomplicated acute type B aortic dissections are often medically managed with good outcomes, a subset develop subacute or chronic aneurysmal dilatation. We hypothesize that computational fluid dynamics (CFD) simulations may be useful in identifying patients at risk for this complication. Methods: Patients with acute type B dissection complicated by rapidly expanding aortic aneurysms (N=7) were compared to patients with stable aortic diameters (N=7). Three dimensional patient-specific dissection geometries were generated from CTA and used in CFD simulations of pulsatile blood flow. Hemodynamic parameters including false lumen flow and wall shear stress were compared. Results: Patients with rapid aneurysmal degeneration had a growth rate of 5.3 ± 2.7 mm/month compared to those with stable aortic diameters who had rates of 0.2 ± 0.02 mm/month. Groups did not differ in initial aortic diameter (36.1±2.9 vs 34.4±3.6 mm, P=0.122) or false lumen size (22.6±2.9 vs 20.2±4.5 mm, P=0.224). In patients with rapidly expanding aneurysms, a greater percentage of total flow passed through the false lumen (78.3±9.3 vs 56.3±11.8%, P=0.016). The time averaged wall shear stress on the aortic wall was also significantly higher (12.6±3.7 vs 7.4±2.8 Pa, P=0.028, see Figure). Conclusions: Hemodynamic parameters derived from CFD simulations of acute type B aortic dissections were significantly different in dissections complicated by aneurysm formation. Thus, CFD may assist in predicting which patients may benefit from early stent grafting.