To review short- and long-term outcomes of all carotid artery stenting (CAS) in patients with radiation induced (RI) internal carotid artery (ICA) stenosis compared with patients with atherosclerotic stenosis (AS).
We performed a single-center, multi-site case-control study of transfemoral carotid artery intervention in patients stented for RI or AS. Cases of stented RI carotid arteries were identified using a CAS database covering 01/2000-12/2019. These patients were randomly matched 2:1 with stented patients due to AS by age, sex and year of CAS. A conditional logistic regression model was performed to estimate the odds of re-intervention in the RI group. Lastly, a systematic review was performed to assess outcomes of RI stenosis treated with CAS.
There were 120 CAS in 113 patients due to RI ICA stenosis. 89 (78.8%) were male and 68 (60.2%) were symptomatic. Reasons for radiation included most commonly treatment for diverse malignancies of the head and neck in 109 (96.5%) patients. Mean radiation dose was 58.9±15.6Gy and time from radiation to CAS was 175.3±140.4 months. Symptoms included 31 transient ischemic attacks (TIA), 21 strokes (7 acute and 14 subacute) and 17 amaurosis fugax. Mean National Institutes of Health Stroke Scale (NIHSS) in acute strokes was 8.7±11.2. In asymptomatic patients, the indication for CAS was high grade stenosis determined by duplex ultrasound. All CAS were successfully completed. Re-interventions were more frequent in the RI ICA stenosis cohort compared with the AS cohort (10.1% versus 1.4%). Re-interventions occurred in 14 vessels and causes for re-intervention were restenosis in 12 followed by TIA/stroke in 2 vessels. On conditional regression modeling, patients with RI ICA stenosis were at a higher risk for re-intervention (OR=7.1 [95% CI=2.1-32.8]; p=0.004). Mean follow-up was 33.7±36.9 months and mortality across groups was no different (p=0.12).
In our single center, multi-site cohort study, patients who underwent CAS for RI ICA stenosis experienced a higher rate of restenosis and a higher number of re-interventions compared to CAS for AS. Although CAS is safe and effective for this RI ICA stenosis cohort, further data is needed to reduce the risk of restenosis and close patient surveillance is warranted. In our systematic review, CAS was considered an excellent alternative option for the treatment of patients with RI ICA stenosis. However, careful patient selection is warranted due to the increased risk of restenosis on long-term follow-up.

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