Intracranial in-stent restenosis (ISR), a common complication of percutaneous transluminal angioplasty and stenting (PTAS), may increase the likelihood of and an earlier incidence of recurrent ischemic events near the stented intracranial artery, according to a study published online Aug. 20 in Stroke.

“During the past decade, [PTAS] has been evolving as a possible treatment option for [intracranial in-stent restenosis] ICAS patients at a particularly high risk for recurrent stroke,” wrote the authors, led by Min Jin, MD, of the New Era Stroke Care and Research Institute in Beijing, China. “Numerous studies have discussed periprocedural complications of PTAS for ICAS. However, reliable data concerning prognosis of ISR patients are lacking so far.”

To prospectively study potential adverse outcomes, Jin and his colleagues followed 226 patients with symptomatic intracranial atherosclerosis who underwent stenting at New Era and later had catheter angiography.  There were a combined 233 lesions among the patients, with 57 placed in the ISR group and 176 in to the non-ISR group.

Their primary outcome measure was ischemic stroke or transient ischemia attack near the stented artery after the angiography. They defined ISR as a verified stenosis of 50 percent or greater within three millimeters of the stent.

After about three years of follow-up, 11.6 percent of the subjects met the endpoint criteria. The ISR group had a significantly higher risk of the ischemic events under investigation (21.1 percent vs. 8.5 percent). The outcomes also occurred earlier on average in the ISR group (9.9 months, compared with 26.6 months). They also found ISR to be an independent risk factor.

Although only a single-institute study with a relatively small number of lesions, the authors argued their research supports the need to manage ISR in this patient population.

“[R]educing the occurrence of ISR should be targeted in future research to improve the efficacy of intracranial PTAS,” they concluded.