INTRODUCTION AND OBJECTIVES Management of tandem lesions of the common carotid artery and the ipsilateral carotid bifurcation is challenging. Endovascular techniques have been helpful in managing these complex lesions; either combined with endarterectomy or with stenting alone. However, data on outcomes of total carotid artery stenting for tandem lesions is scarce. We aim to describe the impact of tandem lesions on outcomes of transcarotid (TCAR) and transfemoral (TFCAS) carotid stenting. METHODS We reviewed the VQI database for carotid artery stenting. Multivariable logistic regression analysis was used to assess the association between tandem lesions and in-hospital outcomes. RESULTS A total of 15,775 underwent TFCAS and 20,673 underwent TCAR. In each procedure, 3.6% of patients had tandem lesion. Patients with tandem lesion were younger, more likely to have high grade stenosis, and to be operated on under general anesthesia. After adjusting for potential confounders, there was no difference in the risk of stroke, death, stroke/TIA, stroke/death, and extended length of stay (ELOS) between tandem vs non-tandem lesion in patients undergoing TCAR. On the other hand, the presence of tandem lesion was associated with higher risk of stroke/TIA (OR: 1.5, 95%CI (1.002-2.3) P=.049) and ELOS (OR: 1.3, 95%CI(1.04-1.6), P=.022)(Table). CONCLUSIONS The presence of tandem lesions did not seem to impact the risk of adverse events in patients undergoing TCAR. However, tandem lesions were associated with 50% increased risk of stroke/TIA and 30% increased risk of ELOS in patients undergoing TFCAS. These results support the advantage of flow reversal over distal embolic protection devices (DEP) as it may be difficult deploying DEP in distal lesions. Studies comparing outcomes of TCAR vs TFCAS in patients with tandem lesions are warranted. Management of tandem lesions of the common carotid artery and the ipsilateral carotid bifurcation is challenging. Endovascular techniques have been helpful in managing these complex lesions; either combined with endarterectomy or with stenting alone. However, data on outcomes of total carotid artery stenting for tandem lesions is scarce. We aim to describe the impact of tandem lesions on outcomes of transcarotid (TCAR) and transfemoral (TFCAS) carotid stenting. We reviewed the VQI database for carotid artery stenting. Multivariable logistic regression analysis was used to assess the association between tandem lesions and in-hospital outcomes. A total of 15,775 underwent TFCAS and 20,673 underwent TCAR. In each procedure, 3.6% of patients had tandem lesion. Patients with tandem lesion were younger, more likely to have high grade stenosis, and to be operated on under general anesthesia. After adjusting for potential confounders, there was no difference in the risk of stroke, death, stroke/TIA, stroke/death, and extended length of stay (ELOS) between tandem vs non-tandem lesion in patients undergoing TCAR. On the other hand, the presence of tandem lesion was associated with higher risk of stroke/TIA (OR: 1.5, 95%CI (1.002-2.3) P=.049) and ELOS (OR: 1.3, 95%CI(1.04-1.6), P=.022)(Table). The presence of tandem lesions did not seem to impact the risk of adverse events in patients undergoing TCAR. However, tandem lesions were associated with 50% increased risk of stroke/TIA and 30% increased risk of ELOS in patients undergoing TFCAS. These results support the advantage of flow reversal over distal embolic protection devices (DEP) as it may be difficult deploying DEP in distal lesions. Studies comparing outcomes of TCAR vs TFCAS in patients with tandem lesions are warranted.