Late Outcomes of Carotid Artery Stenting for Radiation Therapy-Induced Carotid Stenosis

Carotid Artery Stenosis and Ischemic Stroke in Patients With Head and Neck Cancer Treated With Radiation Therapy: A Critical Review

The purpose of this review is to summarize the literature on carotid artery stenosis (CAS) and ischemic stroke (IS) in patients with head and neck cancer (HNC) treated with radiation therapy (RT) to guide assessment, screening, and management strategies. Patients treated with RT for HNC are at an elevated risk of developing CAS, with published meta-analyses demonstrating that CAS >50% occurs in approximately 25% of patients. Previous research suggests a 10-year cumulative incidence of stroke between 5.7% and 12.5%. Cardiovascular disease (CVD) risk prediction tools such as Qstroke, QRISK-2, and Framingham risk score perform poorly for predicting IS for patients with HNC who received RT. Duplex ultrasound is the most common imaging modality to assess CAS, but controversy remains as to the utility of screening asymptomatic individuals. Only 3 of the 5 major HNC survivorship guidelines acknowledge RT as a risk factor for CAS or IS, while only 1 makes a specific recommendation on screening for CAS (American Head and Neck Society). Within the general population, only 1 CVD guideline discusses RT as a risk factor for CAS (Society for Vascular Surgery). Clinicians involved in the care of patients with HNC treated with RT should be aware of the increased risk of CAS and IS and the challenges in risk prediction. Although there is a lack of evidence to make firm recommendations, HNC survivorship recommendations should ensure HNC survivors and primary care providers are informed of these risks and the importance of assessment and management of CVD risk factors. Future studies are required to refine risk prediction models in patients with HNC and to determine those most likely to benefit from targeted screening and initiation of early preventative strategies.

Impact of head and neck radiation on long-term outcomes after carotid revascularization

OBJECTIVE

Radiation-induced carotid artery stenosis (RICS) is a well-described phenomenon seen after head and neck cancer radiation. Previously published literature suggests that, compared with atherosclerotic disease, RICS may result in worse long-term outcomes and early restenosis. This study aims to evaluate the effect of radiation on long-term outcomes after various carotid revascularization techniques using a multi-center registry database.

METHODS

Patients in the Society for Vascular Surgery (SVS) Vascular Quality Initiative (VQI) registry for carotid artery intervention (carotid endarterectomy [CEA]; transfemoral carotid artery stenting [CAS]; transcarotid artery revascularization [TCAR]), who are 65 years or older were included in the study. VQI Vascular Implant Surveillance and Interventional Outcomes Network (VISION) Medicare-linked database was used to obtain long-term procedure-specific outcomes. Primary endpoints were 3-year death, stroke, and reintervention. We performed propensity matching between patients with prior radiation and those without. Kaplan-Meier analysis and a multivariate logistic regression model were used to analyze the outcome variables.

RESULTS

A total of 56,472 patients had undergone carotid revascularization (CEA, n = 48,307; TCAR, n = 4593; CAS, n = 3572), 1244 patients with prior radiation and 54,925 patients without prior radiation. The prior radiation group was more likely to be male (71.9% vs 60.3%; P < .01), to receive a stent (47.5% vs 13.5%; P < .01), and to be on P2Y12 inhibitor (55.2% vs 38.3%; P < .01). Propensity matching was performed on 1223 patients (CEA, n = 655; TCAR, n = 292; CAS, n = 287). There were no significant differences in 30-day outcomes for death, stroke, or major adverse cardiovascular events for all three procedures. The prior radiation group had higher rates of cranial nerve injury (3.7% vs 1.8%; P = .04) and 90-day readmission (23.5% vs 18.3%; P = .01) after CEA. For long-term outcomes, prior radiation significantly increased mortality risk for CEA and CAS (hazard ratio [HR], 1.77; 95% confidence interval [CI], 1.38-2.27 and HR, 1.56; 95% CI, 1.02-2.36, respectively). The 3-year risk of stroke for CEA in radiated patients was also significantly higher (HR, 1.47; 95% CI, 1.03-2.09) compared with non-radiated patients. Prior radiation did not significantly affect death and stroke in patients undergoing TCAR. Prior radiation also did not impact the rates of short and long-term reintervention after CEA, CAS, or TCAR.

CONCLUSIONS

Prior head and neck radiation significantly increases the risk for mortality and stroke for CEA and the risk for mortality after CAS. Long-term outcomes for TCAR are not significantly affected by prior radiation. TCAR may be the preferred treatment modality for patients with radiation-induced carotid stenosis.

Association of Centre Quality Certification with Characteristics of Patients, Management, and Outcomes Following Carotid Endarterectomy or Carotid Artery Stenting

Background: The aim of this study was to analyze the association between center quality certifications and patients' characteristics, clinical management, and outcomes after carotid revascularization. Methods: This study is a pre-planned sub-study of the ISAR-IQ project, which analyzes data from the Bavarian subset of the nationwide German statutory quality assurance carotid database. Hospitals were classified as to whether a certified vascular center (cVC) or a certified stroke unit (cSU) was present on-site or not. The primary outcome event was any stroke or death until discharge from the hospital. Results: In total, 31,793 cases were included between 2012 and 2018. The primary outcome rate in asymptomatic patients treated by CEA ranged from 0.7% to 1.5%, with the highest rate in hospitals with cVC but without cSU. The multivariable regression analysis revealed a significantly lower primary outcome rate in centers with cSU in asymptomatic patients (aOR 0.69; 95% CI 0.56-0.86; p < 0.001). In symptomatic patients needing emergency treatment, the on-site availability of a cSU was associated with a significantly lower primary outcome rate (aOR 0.56; 95% CI 0.40-0.80; p < 0.001), whereas the presence of a cVC was associated with higher risk (aOR 3.07; 95% CI 1.65-5.72). Conclusions: This study provides evidence of statistically significant better results in some sub-cohorts in certified centers. In centers with cSU, the risk of any stroke or death was significantly lower in asymptomatic patients receiving CEA or symptomatic patients treated by emergency CEA.

Imaging Characteristics and Reintervention in Patients After Radiation Induced Carotid Artery Stenting

OBJECTIVE

To evaluate and describe the radiographic imaging findings in a series of patients who underwent re-intervention after radiation-induced carotid artery stenting (RICAS).

METHODS

Retrospective review of patients with prior RICAS and subsequent re-intervention.

RESULTS

We describe ten patients including eight male and two female patients with twelve re-interventions due to prior diagnosed radiation induced carotid artery stenosis (RICS) and subsequent stenting during the period 2000-2019. The rate of re-intervention was found to be 10%. The pattern of stenosis is unique to this patient population including specifically long-segment stenosis, proximal and distal to the stent location, which tends not to occur in the atherosclerotic patient population.

CONCLUSION

Careful surveillance after RICAS is necessary to assess for the risk and the unusual pattern of stenosis to offer re-intervention in this high-risk patient population.

Diabetes and restenosis

Restenosis, defined as the re-narrowing of an arterial lumen after revascularization, represents an increasingly important issue in clinical practice. Indeed, as the number of stent placements has risen to an estimate that exceeds 3 million annually worldwide, revascularization procedures have become much more common. Several investigators have demonstrated that vessels in patients with diabetes mellitus have an increased risk restenosis. Here we present a systematic overview of the effects of diabetes on in-stent restenosis. Current classification and updated epidemiology of restenosis are discussed, alongside the main mechanisms underlying the pathophysiology of this event. Then, we summarize the clinical presentation of restenosis, emphasizing the importance of glycemic control in diabetic patients. Indeed, in diabetic patients who underwent revascularization procedures a proper glycemic control remains imperative.