Clinical Outcomes of Carotid Stenting Comparable in Radiation-Induced and Atherosclerotic Stenoses

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Cancer patients who develop carotid stenosis due to radiation have similar procedural success and short- and long-term hard clinical outcomes with carotid artery stenting (CAS) as patients whose stenoses are atherosclerotic in nature. However, radiation-induced stenosis is associated with more in-stent restenosis, underlining the importance of more frequent follow-up in this subgroup, according to a study published online April 3, 2014, ahead of print in Stroke.

For the single-center study, Thomas W. Leung, MD, of Prince of Wales Hospital (Shatin, Hong Kong), and colleagues prospectively enrolled 65 patients (84 vessels) with radiation-induced stenosis and 129 patients (150 vessels) with atherosclerotic stenosis. All were treated with CAS from October 2006 to April 2010. Patients in the radiation-induced group had previously undergone radiotherapy for a primary head-and-neck cancer.

CAS was performed using a self-expanding closed-cell metallic stent (Carotid WALLSTENT Monorail Endoprosthesis, Boston Scientific, Natick, MA) and a distal cerebral protection device (FilterWire EZ Embolic Protection System, Boston Scientific).

Stroke, Death Similar at 30 Days

While technical success was achieved in all patients, use of multiple stents was more common in the radiation-induced group than the atherosclerotic group (21.7% vs 4.7%; P < 0.001), as was use of balloon size ≥ 6 mm (63% vs 40.5%; P = 0.001).

At 30 days postprocedure, the incidence of stroke or death (primary endpoint) was similar between the radiation-induced group and the atherosclerotic group. At a median follow-up time of 39.4 months in the radiation-induced group and 45.3 months in the atherosclerotic group, cumulative and annual rates of ipsilateral ischemic stroke as well as cumulative mortality were also equivalent (table 1).

Table 1. Rates of Stroke and Death

However, in-stent restenosis was much more common in the radiation-induced group (25.7% vs 4.2%; P < 0.001), as was symptomatic in-stent restenosis (6.8% vs 0.8%; P = 0.03, respectively).

Few Solid Options

The study authors point out that while carotid endarterectomy for radiation-induced stenosis may result in lower 30-day stroke/TIA and in-stent restenosis compared with CAS, it carries a 9.2% risk of transient or permanent cranial nerve injury. Medical therapy, another potential option, “has not been assessed adequately, and the effect of antiplatelet, anticoagulant, antihypertensive, or lipid-lowering therapy in limiting disease progression is still unclear,” they say.

Dr. Leung and colleagues note that while some have raised concerns about the need to alter CAS approaches in radiation-induced stenoses, they inflated balloons to ≤ 12 atmospheres to overcome heavily fibrotic or calcified lesions and oversized balloons by 0.5 to 1 mm in postdilation at carotid bulbs to ensure residual stenosis < 20%. They credit these techniques, along with use of a closed-cell stent, with keeping their complication rates lower than those of some previous studies of stenting in patients with radiation-induced stenosis.

In a telephone interview with TCTMD, Christopher J. White, MD, of the Ochsner Heart and Vascular Institute (New Orleans, LA), said the data are welcome since radiation-induced stenosis is rare with limited published studies available on treating it via stenting. He added that it is becoming even less common as oncologists improve the ability to spare surrounding healthy tissue when radiating head-and-neck cancers.

More Frequent Follow-up Needed in Radiation Cases

“This is a very important trial because it confirms… what interventional cardiologists have said for a long time, which is that we think the correct way to treat radiation arteritis is stenting,” Dr. White said. “I would even be happy if [stenting] was not as effective in these patients as it was for atherosclerosis because it’s still better than nothing, but to know you can benchmark it with atherosclerosis gives you a good sense of what to expect when choosing stenting to treat these folks.”

He added that the evidence clearly supports the consensus guideline recommendation for stenting of radiation-induced stenosis. As for the higher rate of in-stent restenosis in these patients, Dr. White observed that while only some of those patients will require an additional procedure, “these data suggest that the radiation arteritis patients should be followed more frequently [than those] with atherosclerosis.”

Study Details

Median age was 62 years in the radiation-induced stenosis group and 73 years in the atherosclerotic stenosis group; the proportions of men were 81.5% and 78.3%, respectively.

The radiation-induced group had longer lesions, more frequent occurrence of multiple ulcers resembling “candle wax,” and more skipped lesions, while the atherosclerotic group had more calcified plaques (all P < 0.001).

 

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Source:
Yu SCH, Zou WXY, Soo YOY, et al. Evaluation of carotid angioplasty and stenting for radiation-induced carotid stenosis. Stroke. 2014;Epub ahead of print.

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