No Excess Stroke Risk With Intracranial Stents for Severe Stenoses

BEJING, Feb. 5 -- The degree of stenosis does not affect outcomes in elective stenting of intracranial arteries, but the procedure should probably be reserved for major lesions, researchers here reported.

At 30 days, the ischemic stroke rate was 4.8% in patients with 70% stenoses versus 4.3% in those with 50% to 69% stenoses, said Wei-Jian Jiang, M.D., of Tiantan Hospital at the Capital University of Medical Sciences, and colleagues in the Feb. 6 issue of Neurology.

But when that slight risk was balanced against the lower baseline risk of cerebrovascular events, the scales tip toward medical management for patients with moderate intracranial lesions, the investigators said.

"These results imply that compared with the results of medical treatment, the procedure-related primary or secondary endpoint rate of elective stenting may be acceptable for patients with severe stenosis but may not be for patients with moderate stenosis," they wrote.

Dr. Jiang and colleagues analyzed outcomes in a prospective database of stenting for intracranial stenosis at their single center from 2001 to 2005 with follow-up through 2006.

They included only the 213 patients (220 stenoses) who had at least 50% or more stenosis of a major intracranial artery verified by angiography, had already suffered an ischemic stroke or transient ischemic attack, and had at least one atherosclerotic risk factor. The average age was 52.8.

The severe stenosis group included 121 patients and 126 stenoses; the moderate-stenosis group included 94 stenoses in 92 patients.

Baseline characteristics were similar between groups, but there were significantly more long lesions (at least 10 mm) and basilar stenosis in the severe-stenosis group. Overall, the procedure was performed at a median of 30 days after the initial stroke or TIA.

The 30-day primary endpoint findings were similar between groups (hazard ratio 1.13, 95% CI 0.32 to 4.00, P=0.85). The researchers reported:

• Four lesion-related ischemic strokes in the severe stenosis group versus three in the moderate group (HR 1.00, P=1.000),
• No symptomatic brain hemorrhages in the severe stenosis group versus one in the moderate group (HR 0.01, P=0.591), and
• Two symptomatic subarachnoid hemorrhages in the severe stenosis group versus none in the moderate group (HR 50.91, P=0.504).

Severe stenoses were also no more likely to cause 30-day emergent cerebral revascularization (HR 0.56, P=0.451) or asymptomatic subarachnoid hemorrhage (HR 0.01, P=0.446).

Thereafter during the average 26.0 to 27.6 months of follow-up, the cumulative probability of the lesion-related stroke and symptomatic brain or subarachnoid hemorrhage was:

• 7.2% (95% CI 2.6% to 11.8%) at one year for the severe stenosis group,
• 5.3% (95% CI 0.7% to 9.9%) at one year for the moderate stenosis group,
• 8.2% (95% CI 1.9% to 14.5%) at two years for the severe stenosis group, and
• 8.3% (95% CI 1.3% to 15.3%) at two years for the moderate stenosis group.

A previous trial showed the cumulative likelihood of lesion-related ischemic strokes at one year was at least 17% for severe stenosis despite medical therapy, aspirin or Coumadin (warfarin), compared with 7% to 8% for moderate stenosis.

"Indirectly compared with [that] trial, our results suggest that patients with severe stenosis seem to receive the benefit from elective stenting, whereas patients with moderate stenosis may not," Dr. Jiang and colleagues wrote.

"The similar outcomes in the two groups may mean that elective stenting has eliminated the degree of stenosis as a predictor of outcome," they added.

Stent failure, which occurred in 7.7% of cases overall, was the only factor to predict risk of subsequent stroke or symptomatic brain hemorrhage on multivariable analysis in the severe stenosis group (HR 5.31, 95% CI 1.35 to 20.91, P=0.017). There was no likewise predictive factor for the moderate stenosis group.

Again, the researchers said these findings imply benefit for successful stent placement among patients with severe stenosis but not moderate stenosis.

However, they cautioned, "As a suggestive possible benefit, stenting of severe stenosis requires the results of a randomized trial before routine clinical use."

Among patients who underwent angiography at six months, the restenosis rate was not significantly different between groups (25.0% severe stenosis group versus 11.6% moderate stenosis group, P=0.18). Dr. Jiang and colleagues warned that this finding was subject to low test power (0.23).

Interestingly, there was no difference in outcomes between lesions treated with coronary and Apollo stents.

Limitations of the study included that not all cases were blinded to the neurologist who adjudicated subsequent strokes and there could have been a referral bias for patients to have the procedure in the first place.