Preoperative Aortic Low-Attenuation Plaque and Computed Tomography-Detected Distal Embolism After Hybrid Aortic Arch Repair.

OBJECTIVE: To assess whether preoperative low-attenuation plaque (LAP) burden is associated with postoperative computed tomography (CT)-detected distal embolism after hybrid aortic arch repair, and to characterize its anatomical distribution and clinical impact. METHODS: In this single-center retrospective cohort, 128 patients who underwent hybrid aortic arch repair (Ishimaru zones 0-2) with paired pre- and postoperative contrast-enhanced CT between 2016 and 2024 were analyzed. Aortic plaque composition was quantified at the aortic arch and mid-descending thoracic aorta; LAP and intermediate-attenuation plaque (IAP) were defined as 0-60 and 61-130 Hounsfield units (HU), respectively. Total LAP and IAP burdens were calculated as the sum of the arch and mid-descending aortic areas. Distal embolism was defined as any new postoperative perfusion defect in the liver, spleen, kidneys, or intestine. Risk factors were assessed using logistic regression, and early and mid-term outcomes were compared between high and low LAP groups. RESULTS: CT-detected distal embolism occurred in 12 of 128 patients (9.4%), most commonly involving the kidneys and spleen. In univariable analysis, female sex, current smoking, peripheral arterial disease, and total LAP burden were associated with distal embolism. In the multivariable model, total LAP burden remained the only independent factor (odds ratio per 10 mm2, 1.18; 95% CI, 1.09-1.30; p < 0.001). Freedom from all-cause mortality was significantly lower in the high LAP group (log-rank p = 0.003). CONCLUSIONS: Preoperative aortic LAP burden was independently associated with CT-detected distal embolism after hybrid aortic arch repair. High LAP burden was associated with increased distal embolism and worse long-term survival, suggesting that LAP-based plaque characterization may improve preoperative embolic risk stratification in complex arch interventions.