But after such events, “good medical treatment can be carried out and is effective in preventing difficulties,” one expert says.
The majority of strokes that occur after the periprocedural period among patients treated with stenting for intracranial atherosclerotic disease (ICAD) are due to in-stent restenosis, according to a post hoc analysis of the SAMMPRIS trial.
Moreover, as pointed out to Neurovascular Exchange by Frank J. Veith, MD (NYU Langone Medical Center, New York, NY, and Cleveland Clinic, OH), the study also demonstrates that optimal medical therapy is both feasible and effective, a finding that could prove relevant for the treatment or carotid artery stenosis as well.
For their study recently published online in Stroke, Colin P. Derdeyn, MD, and colleagues examined data on the 183 patients who were randomized to the stenting arm of the SAMMPRIS trial, were successfully treated with the Wingspan stent (Boston Scientific/Stryker Neurovascular), and did not have any periprocedural events.
“Prior studies were retrospective or mixed symptomatic and asymptomatic [in-stent restenosis (ISR)],” Derdeyn told NVX in an email. “Because the study did not allow routine follow-up imaging for surveillance, this was a very nice, clean, uncontaminated estimate of symptomatic ISR. In the prior studies, many patients with asymptomatic ISR were treated with repeat angioplasty, [so] we would not know if they would have developed symptoms or not.”
Overall, by the end of 3 years, 14% of patients in the stenting cohort of SAMMPRIS had experienced symptomatic in-stent restenosis.
During a median follow-up period of 35.0 months, 27 patients (14.8%) experienced a symptomatic infarction (defined as a stroke or cerebral infarct with temporary signs) and 16 (8.7%) had a transient ischemic (TIA) attack alone in the territory. Of the 27 patients with infarctions, 17 (9.3%) had an ischemic stroke and 10 (5.5%) had a cerebral infarct with temporary signs alone.
Adequate vascular imaging to evaluate in-stent restenosis was available for 24 patients with infarctions. This revealed in-stent restenosis in 16 (66.7%). Among the 10 patients with TIA alone, eight (80%) showed evidence of in-stent restenosis.
All five patients with both cerebral infarctions and in-stent restenosis were treated medically, of whom four received dual antiplatelet therapy. All remained stroke-free during a median follow-up period of 26.6 months, although one had a TIA and another had a cerebral infarction with transient signs. Seven of the nine patients with a TIA and in-stent restenosis were treated medically, three with dual antiplatelet therapy and four with aspirin (the other two underwent angioplasty). Once again, none experienced a stroke, although one had a cerebral infarction with transient signs and three had recurrent TIAs during follow-up.
In-Stent Restenosis ‘Needs to Be Overcome’
“The majority of strokes beyond the periprocedural period for [stented] SAMMPRIS patients was related to ISR,” Derdeyn said. While the rate falls within the range of earlier reports, “it is a cause for concern, because it indicates another area that needs to be overcome for stenting for ICAD to be successful,” he added, noting that it’s unclear how to reduce these events.
Future studies on ICAD should focus on “identifying high-risk groups that might benefit from angioplasty and stenting,” Derdeyn suggested. “SAMMPRIS showed for a large general population there was no benefit. There may be hemodynamic factors or imaging studies that identify patients with ruptured atherosclerotic plaques who might do well with medical therapy alone, or imaging selection for patients who have lower risks of perforator stroke or hemorrhage after angioplasty.” He also called for continued research into novel devices, such as balloons or balloon/stent combinations, to see if a lower-risk intervention for ICAD can be developed. Of course, in-stent restenosis rates will require ongoing monitoring, he added.
To NVX, Veith praised the study for showing “an unexpected finding: late stent stenosis inside the head with the particular stents they were using can cause strokes.” More importantly, he said, it reveals “good medical treatment can be carried out and is effective in preventing difficulties.”
The findings could have important implications for the treatment of carotid stenosis, said Veith, observing that this is an area in which the utility of optimal medical therapy remains controversial. Veith himself believes that medical therapy is a better option than either carotid stenting or endarterectomy, particularly for asymptomatic disease, but others argue that optimal medical therapy cannot be achieved because it is impractical and not adhered to by patients. “This shows it can be done in setting of intracranial stenting,” and that it was effective, he said.
Of course, it remains unclear whether the findings will apply to carotid artery disease as well. The results of CREST 2 may provide some answers, Veith suggested.
Source:
Derdeyn CP, Fiorella D, Lynn MJ, et al. Nonprocedural symptomatic infarction and in-stent restenosis after intracranial angioplasty and stenting in the SAMMPRIS Trial (Stenting and Aggressive Medical Management for the Prevention of Recurrent Stroke in Intracranial Stenosis). Stroke. 2017;Epub ahead of print.
Disclosures:
Derdeyn and Veith report no relevant conflicts of interest.
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