Abstract 10736: Statistical Shape Modeling Reveals Anatomic Shape Features Associated With the Outcome of Optimal Medical Therapy in Uncomplicated Type B Aortic Dissection

Abstract

Introduction: Currently, Type B aortic dissection (TBAD) without the presence of either organ malperfusion or aortic rupture is managed with optimal medical therapy (OMT) consisting of an aggressive anti-hypertensive medical regimen and surveillance imaging. Although OMT achieves excellent early survival, the long-term outcomes with OMT alone remain poor. In this study, we identified anatomic shape features that correlate with OMT failure and aortic growth rates in uncomplicated TBAD via statistical shape modeling (SSM). Methods: Contrast CT scans of patients with acute uncomplicated TBAD were analyzed from 25 patients who were initially treated with OMT. OMT failure was defined as aortic intervention (surgical or endovascular repair, n = 8). Statistical shape models were constructed using principal component analysis (PCA) and partial least square regression (PLSR) to extract anatomic shape features from the aorta and flap geometries. For 14 of the 25 patients, additional follow-up CT scans (5 to 117 months) were used to quantify the rate of aortic expansion. Results: Four PCA (feature 5: p = 0.048, 12: p = 0.005, 14: p = 0.047, 24: p = 0.038) and two PLSR (feature 1: p = 0.000, 2: p = 0.004) shape features were effective at separating OMT failure patients and patients who were adequately treated with OMT. Two PCA features were moderately correlated with aortic growth rate (correlation coefficient, feature 11; r = 0.579, 21: r = 0.503). A PLSR feature was correlated with the growth rate (r = 0.867). Representative shape features are shown in Figure 1. Conclusions: Anatomic shape features extracted from SSM were correlated with the outcomes of OMT and aortic growth rate. SSM shape features may provide additional anatomic risk factors in addition to aortic diameter that predicts aneurysmal degeneration and the need for surgical intervention. Future investigations will incorporate the SSM shape features to determine the risk of OMT failure in uncomplicated TBAD patients.