ACT 1 Analysis Shows Low Rate of Stent Fractures and No Association With Major Adverse Events in CAS

September 21, 2016—Ido Weinberg, MD, presented findings on stent fractures in the ACT 1 (Asymptomatic Carotid Trial) study during the third Late-Breaking Trials session at VIVA 16, the 14th annual Vascular InterVentional Advances meeting, which was sponsored by VIVA Physicians, Inc. and held September 18–22, 2016 at the Wynn Las Vegas in Las Vegas, Nevada. 

Dr. Weinberg noted that ACT 1 is the largest prospective, multicenter randomized trial of standard-risk asymptomatic patients with severe carotid artery stenosis who were randomized to carotid artery stenting (CAS) with the Xact stent (Abbott Vascular) or carotid endarterectomy (CEA).

The background of the analysis presented at VIVA 16 is that the rate of stent fractures in CAS and its association with neurologic or cardiac events, death, or in-stent restenosis has only been studied in small series. The objective of this study was to report the stent fracture rate as well as its association with carotid in-stent restenosis and clinically meaningful adverse outcomes in ACT 1.

Dr. Weinberg reported that all patients were required to undergo duplex ultrasound (DUS) surveillance at 30 days and annually thereafter. After 771 patients had been randomized, all subsequent randomized patients were required to also undergo annual radiographic analysis for stent fracture. All DUS and radiographic images were independently adjudicated by a vascular core laboratory (VasCore, Massachusetts General Hospital).

The primary endpoint was the composite of death, stroke (ipsilateral or contralateral; major or minor), or myocardial infarction during the 30 days after the procedure and ipsilateral stroke during the 365 days after the procedure.

Of 1,021 patients who were randomized to CAS, 822 had at least one radiographic study and one DUS during a follow-up period of 5 years. Stent fractures were reported in 51 patients (5.4%). Adverse clinical outcomes up to 5 years occurred in 47 CAS patients enrolled in ACT 1 (5.2%). There was no association between stent fracture and restenosis (P = .53). Neither stent fracture (P = .73) nor restenosis (P = .56) was associated with the primary endpoint to 5 years.

ACT 1 demonstrated a low carotid stent fracture rate and that stent fractures were not associated with major adverse clinical events or in-stent restenosis, concluded Dr. Weinberg at VIVA 16.