Prediction of Long Term Restenosis Risk After Surgery in the Carotid Bifurcation by Hemodynamic and Geometric Analysis

Abstract

This study explored the potential of hemodynamic disturbances and geometric features to predict long-term carotid restenosis after carotid endarterectomy (CEA). Thirteen CEA for carotid diameter stenosis > 70% were performed with patch graft (PG) angioplasty in nine cases, and primary closure (PC) in four cases. MRI acquisitions within one month after CEA were used for hemodynamic and geometric characterization. Personalized computational hemodynamic simulations quantified the exposure to low and oscillatory wall shear stress (WSS). Geometry was characterized in terms of flare (the expansion at the bulb) and tortuosity. At 60 months after CEA, Doppler ultrasound (DUS) was applied for restenosis detection and intima-media thickness determination. Larger flares were associated to larger exposure to low WSS (Pearson R² values up to 0.38, P < 0.05). The two cases characterized by the highest flare and the largest low WSS exposure developed restenosis > 50% at 60 months. Linear regressions revealed associations of DUS observations of thickening with flare variables (up to R² = 0.84, P < 0.001), and the exposure to low (but not oscillatory) WSS (R² = 0.58, P < 0.05). Our findings suggest that arteriotomy repair should avoid a large widening of the carotid bulb, which is linked to restenosis via the generation of flow disturbances. Hemodynamics and geometry-based analyses hold potential for (1) preoperative planning, guiding the PG vs. PC clinical decision, and (2) stratifying long-term restenosis risk after CEA.

Keywords: Carotid endarterectomy; Computational fluid dynamics; Flare; Recurrent stenosis; Tortuosity; Wall shear stress.