Association of residual stenosis after balloon angioplasty with vessel wall geometries in intracranial atherosclerosis

Impact of post-procedure stenosis on outcomes of patients with severe intracranial stenosis treated with intracranial stent placement

BACKGROUND

The optimal target post-procedure stenosis after percutaneous angioplasty and stent placement (PTAS) for intracranial stenosis is unknown. We determined the effect of post-procedure stenosis after intracranial PTAS on subsequent clinical events in patients with severe symptomatic intracranial stenosis.

METHODS

We categorized the severity of post-procedure stenosis as '<30%', '30-49%', and '≥50%' among 207 patients who underwent PTAS in a multicenter randomized clinical trial. Outcomes included stroke or death within 72 hours and within 30 days, ipsilateral stroke beyond 30 days of treatment, and stroke or death within 30 days or stroke in the qualifying artery beyond 30 days (primary endpoint of the trial). Cox proportional hazards analysis was performed with adjustments for age, initial severity of stenosis, location of stenosis, and qualifying event. Kaplan-Meier curves were generated for the primary endpoint stratified by post-procedure stenosis with log-rank analysis.

RESULTS

The severity of post-procedure stenosis was categorized as <30%, 30-49%, and ≥50% in 112, 73, and 22 patients, respectively. Compared with patients with post-procedure stenosis <30%, there was no difference in the risk of primary endpoint among patients with post-procedure stenoses of 30-49% (hazards ratio (HR) 0.85, 95% confidence interval (95% CI) 0.64 to 1.15) or those with ≥50% (HR 0.91, 95% CI 0.57 to 1.43). Log-rank analysis did not demonstrate a difference in rates of primary endpoint between groups stratified by post-procedure stenosis (P=0.70).

CONCLUSION

In the absence of any benefit on short- and long-term outcomes, strategies to achieve a low severity of post-procedure stenosis among patients with severe intracranial stenosis may not be warranted.

Association of periprocedural perfusion non-improvement with recurrent stroke after endovascular treatment for Intracranial Atherosclerotic Stenosis

Background

Predictors of recurrent stroke after endovascular treatment for symptomatic intracranial atherosclerotic stenosis (ICAS) remain uncertain.

Objectives

Among baseline characteristics, lesion features, and cerebral perfusion changes, we try to explore which factors are associated with the risk of recurrent stroke in symptomatic ICAS after endovascular treatment.

Design

Consecutive patients with symptomatic ICAS of 70-99% receiving endovascular treatment were enrolled. All patients underwent whole-brain computer tomography perfusion (CTP) within 3 days before and 3 days after the endovascular treatment. Baseline characteristics, lesion features, and cerebral perfusion changes were collected.

Methods

Cerebral perfusion changes were evaluated with RAPID software and calculated as preprocedural cerebral blood flow (CBF) < 30%, time to maximum of the residue function (Tmax) > 6 s, and Tmax > 4 s volumes minus postprocedural. Cerebral perfusion changes were divided into periprocedural perfusion improvement (>0 ml) and non-improvement (⩽ 0 ml). Recurrent stroke within 180 days was collected. The Cox proportional hazards analysis analyses were performed to evaluate factors associated with recurrent stroke.

Results

From March 2021 to December 2021, 107 patients with symptomatic ICAS were enrolled. Of the 107 enrolled patients, 30 (28.0%) patients underwent balloon angioplasty alone and 77 patients (72.0%) underwent stenting. The perioperative complications occurred in three patients. Among CBF < 30%, Tmax > 6 s, and Tmax > 4 s volumes, Tmax > 4 s volume was available to evaluate cerebral perfusion changes. Periprocedural perfusion improvement was found in 77 patients (72.0%) and non-improvement in 30 patients (28.0%). Nine patients (8.4%) suffered from recurrent stroke in 180-day follow-up. In Cox proportional hazards analysis adjusted for age and sex, perfusion non-improvement was associated with recurrent stroke [hazards ratio (HR): 4.472; 95% CI: 1.069-18.718; p = 0.040].

Conclusion

In patients with symptomatic ICAS treated with endovascular treatment, recurrent stroke may be related to periprocedural cerebral perfusion non-improvement.

Registration

http://www.chictr.org.cn. Unique identifier: ChiCTR2100052925.

3D Enhancement Color Maps in the Characterization of Intracranial Atherosclerotic Plaques

BACKGROUND AND PURPOSE

High-resolution MR imaging allows the identification of culprit symptomatic plaques after the administration of gadolinium. Current high-resolution MR imaging methods are limited by 2D multiplanar views and manual sampling of ROIs. We analyzed a new 3D method to objectively quantify gadolinium plaque enhancement.

MATERIALS AND METHODS

Patients with stroke due to intracranial atherosclerotic disease underwent 7T high-resolution MR imaging. 3D segmentations of the plaque and its parent vessel were generated. Signal intensity probes were automatically extended from the lumen into the plaque and the vessel wall to generate 3D enhancement color maps. Plaque gadolinium (Gd) uptake was quantified from 3D color maps as gadolinium uptake = (µPlaque T1 + Gd -µPlaque T1/SDPlaque T1). Additional metrics of enhancement such as enhancement ratio, variance, and plaque-versus-parent vessel enhancement were also calculated. Conventional 2D measures of enhancement were collected for comparison.

RESULTS

Thirty-six culprit and 44 nonculprit plaques from 36 patients were analyzed. Culprit plaques had higher gadolinium uptake than nonculprit plaques (P < .001). Gadolinium uptake was the most accurate metric for identifying culprit plaques (OR, 3.9; 95% CI 2.1-8.3). Gadolinium uptake was more sensitive (86% versus 70%) and specific (71% versus 68%) in identifying culprit plaques than conventional 2D measurements. A multivariate model, including gadolinium uptake and plaque burden, identified culprit plaques with an 83% sensitivity and 86% specificity.

CONCLUSIONS

The new 3D color map method of plaque-enhancement analysis is more accurate for identifying culprit plaques than conventional 2D methods. This new method generates a new set of metrics that could potentially be used to assess disease progression.