Carotid stent fractures do not affect outcomes in ACT 1 population

LAS VEGAS — In an analysis of patients from the ACT 1 randomized trial of carotid artery stenting vs. endarterectomy, in those assigned carotid artery stenting, stent fractures were not linked to death, stroke, MI or restenosis, according to a presentation at VIVA 16.

Among the 1,021 patients assigned carotid artery stenting with the same stent system (Xact, Abbott Vascular) in ACT 1, all of whom were aged 79 years or younger, had asymptomatic severe carotid artery stenosis and were at low surgical risk, 51 (5.4%) had stent fractures at 5 years, according to Ido Weinberg, MD, vascular medicine specialist at Massachusetts General Hospital.

Ido Weinberg

“Most fractures were grade I fractures, which is a fracture of a single tine,” Weinberg said at a press conference.

Those who had a stent fracture did not differ demographically from those who did not except that those with fracture were more likely to have had a previous endarterectomy (13.7% vs. 5.3%; P = .02), he said.

In terms of angiographic differences, those with stent fracture had more calcification in their lesions than those who did not, according to Weinberg.

Restenosis rates, defined as at least 70% stenosis according to duplex ultrasound, were low and did not differ between those with stent fracture (4.4%; 95% CI, 0.5-15.1) and those without (5.3%; 95% CI, 3.7-7.3), he said.

There was no significant difference between the groups at 5 years in the primary outcome of death, stroke and MI (fracture, 4.1%; no fracture, 5.2%; P = .68), in stroke (fracture, 8.7%; no fracture, 6.7%; P = .69), in death (fracture, 2.6%; no fracture, 13%; P = .08) or clinically driven target lesion revascularization (fracture, 2%; no fracture, 1.7%; P = .67), Weinberg said.

Limitations included that most patients did not have an X-ray performed at all time points of the study, and not all patients had at least one interpretable X-ray and one interpretable duplex ultrasound, he said.

“Carotid stents have a very low fracture rate overall, and more study is needed to evaluate the correlation between stent fracture and pre-existing factors,” Weinberg said at the press conference. “More study is needed to understand when stent fractures occur. These results are applicable only to the Xact stent, and further studies are needed for generalizability.” – by Erik Swain

Reference:

Weinberg I, et al. Late-Breaking Clinical Trials. Presented at: VIVA 16; Sept. 18-22, 2016; Las Vegas.

Disclosure: The ACT 1 study was funded by Abbott Vascular. Weinberg reports no relevant financial disclosures.