Hemodynamic Tandem Intracranial Lesions on Magnetic Resonance Angiography in Patients Undergoing Carotid Endarterectomy

Abstract

Background Hemodynamic tandem intracranial lesions ( TIL s) on intracranial magnetic resonance angiography, which develop flow dependently, have been overlooked clinically in patients undergoing carotid endarterectomy. As they represent severe baseline hemodynamic compromise at the segment, they may be associated with distinctive clinical outcomes. Methods and Results We assessed 304 consecutive carotid endarterectomy cases treated over 3 years. Included cases had both preoperative and postoperative intracranial 3‐dimensional time‐of‐flight magnetic resonance angiography, of which signal intensities are flow dependent, and postoperative diffusion‐weighted imaging (≤3 days following carotid endarterectomy). Preoperative TIL s in the ipsilateral intracranial arteries were evaluated by the presence of nonexclusive components: focal stenosis (>50%), diffuse stenosis (>50%), and decreased signal intensities (>50%). The components showing postoperative normalization were considered hemodynamic. TIL s with hemodynamic components were defined as hemodynamic TIL s, while others as consistent TIL s. Baseline characteristics and postoperative outcomes were analyzed among 3 groups: no TIL s, consistent TIL s, and hemodynamic TIL s. Preoperative TIL s were identified in 104 (34.2%) cases; 54 (17.8%) had hemodynamic components. Diffuse stenosis and decreased signal intensities were usually reversed postoperatively. Patients with hemodynamic TIL s tended to have severe proximal carotid stenosis and recent strokes (≤14 days). For the outcome, hemodynamic TIL s were independently associated with the advent of postoperative ischemic lesions on diffusion‐weighted imaging (odds ratio: 2.50; 95% CI, 1.20–5.20). Conclusions In patients undergoing carotid endarterectomy, a significant number of preoperative TIL s demonstrated hemodynamic components, which were reversed postoperatively. The presence of such components was distinctively associated with the postoperative incidence of new ischemic lesions.