Key Points:
• Chinese registry study looks at safety, efficacy of stenting for symptomatic intracranial stenosis
• Technical success 97.3%; 30-day rate of stroke/TIA/death is 4.3%
Despite poor outcomes in 2 US trials, stenting may be a reasonably safe and effective treatment for severe symptomatic intracranial stenosis in the right circumstances, according to a Chinese registry study published online August 18, 2015, ahead of print in Stroke.
Investigators led by Zhongrong Miao, MD, of Beijing Tiantan Hospital (Beijing, China), evaluated 300 patients (mean age 58.3 years; 76% men) with symptomatic severe intracranial stenosis and poor collaterals who were treated with a balloon-mounted stent (Apollo; MicroPort Neuro Tech; Shanghai, China; n = 159) or balloon dilation plus a self-expanding stent (Gateway balloon; Wingspan stent; Stryker; n = 141) at 15 Chinese centers. The patients were enrolled in a prospective registry between September 2013 and January 2015.
The mean stenosis was 84.3%. Hypoperfusion was confirmed in all patients by digital subtraction angiography. The mean time from the qualifying event (stroke in 54.3%) to endovascular treatment was 21 days. Patients treated with balloon-mounted stents were older, less likely to have middle cerebral artery lesions and Mori C lesions, and more likely to have vertebral artery lesions and Mori A lesions.
Encouraging 30-Day Results
Overall, revascularization was successful in 97.3% of patients, with a mean residual stenosis of 8.5%. At 30 days, the composite of stroke, TIA, or death (primary endpoint) occurred in 4.3% of patients, ischemic stroke in 2.3%, hemorrhagic stroke in 0.3%, and TIA in 1.7%; all events were related to the target territory.
Outcomes were similar between the 2 stenting techniques, except for a lower mean residual stenosis in patients treated with balloon-mounted stenting than in those treated with a balloon plus self-expanding stent (6.1% vs 11.3%; P = 0.000).
Superior Outcomes to US Trials
The study authors offer several likely reasons why the study outcomes are superior to those seen in the US SAMMPRIS and VISSIT trials. “Patients enrolled in this study were selected for hypoperfusion etiology, effectively excluding patients with perforator strokes,” they say. Moreover, the time from the qualifying event to stenting is longer than the delays in the SAMMPRIS (median 7 days) and VISSIT (median 9 days) trials, allowing for better stabilization of plaque , which reduces the likelihood of thromboembolic events in the periprocedural period, they observe.
In addition, patients in the current study had lower LDL levels than those in the SAMMPRIS and VISSIT trials; lower LDL has been associated with fewer periprocedural complications in studies of carotid stenting. Furthermore, the operators in this study had the choice of using either a balloon-mounted stent or a self-expanding stent “to maximize success and minimize procedural complications,” Dr. Miao and colleagues say.
Technique, Timing, Patient Selection Make a Difference
“Symptomatic [intracranial stenosis] is most common in Asian populations,” Philip M. Meyers, MD, of Columbia University Medical Center (New York, NY), told WLNCMD in a telephone interview. “Therefore, Chinese physicians have need to perform cerebral revascularization procedures more commonly in their patients than in the United States. They are reporting good outcomes—better than had been shown in the SAMMPRIS and VISSIT trials in the United States. But the Chinese report is derived from registry data, while SAMMPRIS and VISSIT were clinical trials, so they are not directly comparable.
“This paper contains useful information, but a randomized, controlled trial would be important to confirm the results they have obtained here,” he added.
Dr. Meyers said that while there is clearly a role for intracranial revascularization with angioplasty or stent-supported angioplasty, appropriate patient populations remain to be identified in the United States. He and colleagues are currently enrolling patients in the WEAVE (Wingspan Stent System Post Market Surveillance Study) trial to do just that.
Start With Angioplasty
Good outcomes for intracranial stenting are a matter of timing and technique, L. Nelson Hopkins, MD, of University at Buffalo Neurosurgery (Buffalo, NY), told WLNCMD in a telephone interview. This study “would not change my practice regarding using stents during the acute phase of disease, when plaques are very unstable, because the intracranial vasculature lacks strength,” he said.
The high mortality and morbidity rate associated with symptomatic intracranial stenting even with aggressive medical therapy means better treatments are needed, Dr. Hopkins asserted. “We started back in late 1990s treating with submaximal angioplasty, and it has been very effective at stopping symptoms and preventing further problems because it opens up enough of a channel so flow can get through,” he explained, adding that a very small increase in lumen diameter has a big effect. “Then we come back in a few months and reevaluate, and if the stenosis is back to being very severe, we have more- stable plaque that is asymptomatic. Probably we injured the plaque with the angioplasty, so it is more fibroproliferative, so now we can put in a stent almost with impunity.”
Sources:
Miao Z, Zhang Y, Shuai J, et al. Thirty-day outcome of a multicenter registry study of stenting for symptomatic intracranial artery stenosis in China. Stroke. 2015;Epub ahead of print.
Disclosures:
• Dr. Miao reports no relevant conflicts of interest.
• Dr. Meyers reports no relevant conflicts of interest.
• Dr. Hopkins reports owning stock in Boston Scientific.
