Stenting in Intracranial Stenosis: Current Controversies and Future Directions

Self-expanding intracranial drug-eluting stent system in patients with symptomatic intracranial atherosclerotic stenosis: initial experience and midterm angiographic follow-up

BACKGROUND

Symptomatic intracranial atherosclerotic stenosis (ICAS) is a major cause of ischemic stroke worldwide. In patients undergoing endovascular treatment for ICAS, in-stent restenosis (ISR) is associated with ischemic stroke recurrence.

OBJECTIVE

Intracranial drug-eluting self-expanding stent systems (COMETIU; Sinomed Neurovita Technology Inc., CHN) are new devices for treating ICAS. This study evaluated the perioperative experience and medium-term outcomes of COMETIU in 16 patients.

METHODS

We prospectively analyzed 16 patients with ICAS (≥ 70% stenosis) who underwent intravascular therapy between September 4, 2022, and February 1, 2023. The primary outcome was the incidence of ISR at 6 months postoperatively. The secondary efficacy outcomes were device and technical success rates. The secondary safety outcomes included stroke or death within 30 days after the procedure and the cumulative annual rate of recurrent ischemic stroke in the target-vessel territory from 31 days to 6 months and 1 year.

RESULTS

A total of 16 patients with 16 intracranial atherosclerotic lesions were treated with 16 COMETIUs. All procedures were performed under general anesthesia with 100% device and technical success rates, with no cases of periprocedural stroke or death. The mean radiographic follow-up duration was at least 6 months postoperatively, and all patients presented for radiographic and clinical follow-up. There were no reported ischemic or hemorrhagic strokes. Angiographic follow-up for all patients revealed no cases of ISR.

CONCLUSION

COMETIU is safe and effective for treating ICAS, with minimal risk during the procedure and a low rate of ISR during medium-term follow-up.

Endovascular therapy versus medical treatment for symptomatic intracranial artery stenosis

BACKGROUND

Intracranial artery stenosis (ICAS) is an arterial narrowing in the brain that can cause stroke. Endovascular therapy (ET) and conventional medical treatment (CMT) may prevent recurrent ischaemic stroke caused by ICAS. However, there is no consensus on the best treatment for people with ICAS.

OBJECTIVES

To evaluate the safety and efficacy of endovascular therapy plus conventional medical treatment compared with conventional medical treatment alone for the management of symptomatic intracranial artery stenosis.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register, CENTRAL, MEDLINE, Embase, four other databases, and three trials registries on 16 August 2022. We contacted study authors and researchers when we required additional information.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing ET plus CMT with CMT alone for the treatment of symptomatic ICAS. ET modalities included angioplasty alone, balloon-mounted stent, and angioplasty followed by placement of a self-expanding stent. CMT included antiplatelet therapy in addition to control of risk factors such as hypertension, hyperlipidaemia, and diabetes.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the records to select eligible RCTs, then extracted data from them. We resolved any disagreements through discussion, reaching consensus decisions among the full team. We assessed risk of bias and applied the GRADE approach to assess the certainty of the evidence. The primary outcome was death by any cause or non-fatal stroke of any type within three months of randomisation. Secondary outcomes included all-cause death or non-fatal stroke of any type occurring more than three months after randomisation, ipsilateral stroke, transient ischaemic attack, ischaemic stroke, haemorrhagic stroke, death, restenosis, dependency, and health-related quality of life.

MAIN RESULTS

We included four RCTs with 989 participants who had symptomatic ICAS, with an age range of 18 to 85 years. We identified two ongoing RTCs. All trials had high risk of performance bias, as it was impossible to blind participants and personnel to the intervention. Three trials were terminated early. One trial was at high risk of attrition bias because of substantial loss to follow-up after one year and a high proportion of participants transferring from ET to CMT. The certainty of evidence ranged from low to moderate; we downgraded for imprecision. Compared to CMT alone, ET plus CMT probably increases the risk of short-term death or stroke (risk ratio (RR) 2.93, 95% confidence interval (CI) 1.81 to 4.75; 4 RCTs, 989 participants; moderate certainty), short-term ipsilateral stroke (RR 3.26, 95% CI 1.94 to 5.48; 4 RCTs, 989 participants; moderate certainty), short-term ischaemic stroke (RR 2.24, 95% CI 1.30 to 3.87; 4 RCTs, 989 participants; moderate certainty), and long-term death or stroke (RR 1.49, 95% CI 1.12 to 1.99; 4 RCTs, 970 participants; moderate certainty). Compared to CMT alone, ET plus CMT may increase the risk of short-term haemorrhagic stroke (RR 13.49, 95% CI 2.59 to 70.15; 4 RCTs, 989 participants; low certainty), short-term death (RR 5.43, 95% CI 1.21 to 24.40; 4 RCTs, 989 participants; low certainty), and long-term haemorrhagic stroke (RR 7.81, 95% CI 1.43 to 42.59; 3 RCTs, 879 participants; low certainty). It is unclear if ET plus CMT compared with CMT alone has an effect on the risk of short-term transient ischaemic attack (RR 0.79, 95% CI 0.30 to 2.07; 3 RCTs, 344 participants; moderate certainty), long-term transient ischaemic attack (RR 1.05, 95% CI 0.50 to 2.19; 3 RCTs, 335 participants; moderate certainty), long-term ipsilateral stroke (RR 1.78, 95% CI 1.00 to 3.17; 4 RCTs, 970 participants; moderate certainty), long-term ischaemic stroke (RR 1.56, 95% CI 0.77 to 3.16; 4 RCTs, 970 participants; moderate certainty), long-term death (RR 1.61, 95% CI 0.77 to 3.38; 4 RCTs, 951 participants; moderate certainty), and long-term dependency (RR 1.51, 95% CI 0.93 to 2.45; 4 RCTs, 947 participants; moderate certainty). No subgroup analyses significantly modified the effect of ET plus CMT versus CMT alone. The trials included no data on restenosis or health-related quality of life.

AUTHORS' CONCLUSIONS

This review provides moderate-certainty evidence that ET plus CMT compared with CMT alone increases the risk of short-term stroke and death in people with recent symptomatic severe ICAS. This effect was still apparent at long-term follow-up but appeared to be due to the early risks of ET; therefore, there may be no clear difference between the interventions in terms of their effects on long-term stroke and death. The impact of delayed ET intervention (more than three weeks after a qualifying event) warrants further study.

Endovascular Therapy for Symptomatic Intracranial Artery Stenosis: a Systematic Review and Network Meta-analysis

Intracranial artery atherosclerotic stenosis (ICAS) is one of the most common causes of stroke. Endovascular therapy including balloon angioplasty alone (BA), balloon-mounted stent (BMS), or self-expanding stent (SES) was an important alternative to treat symptomatic ICAS refractory to medical treatment, while none of the three subtypes has been established to be the primary option. We conducted a systematic review and network meta-analysis to determine both the safety and efficacy and establish a hierarchy of different endovascular therapies on symptomatic ICAS. Major databases including MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials were searched for studies comparing outcomes of three different endovascular approaches and other comparable non-endovascular therapies for symptomatic ICAS patients published from 1 January 2000 to 1 November 2021. Primary outcomes included short-term mortality or stroke rate (peri-procedural, or mean follow-up ≤ 3 months), and long-term mortality or stroke rate (mean follow-up ≥ 6 months). Pairwise and network meta-analyses based on the above systematic review were conducted. A total of 19 eligible studies involving 3386 patients treated with 4 different approaches (BA, SES, BMS, and medical treatment) were analyzed. For primary outcome, BA had the highest ranking (SUCRA value 78), followed by BMS (SUCRA value 21.5) and SES (SUCRA value 13.1). The short-term mortality or stroke rate was significantly lower in the BA group compared to SES (OR = 2.50; 95% CI 1.12 to 5.57; p = 0.026) or BMS (OR = 0.43; 95% CI 0.19 to 0.96; p = 0.038). Other primary and secondary outcomes were no different among all three types of endovascular therapy. Overall, the studies were of good methodological quality and the consistency was acceptable across all network meta-analyses. BA offers the highest level of safety outcomes in terms of short-term mortality or stroke in treating symptomatic patients with intracranial artery stenosis, compared to SES and BMS, which needs to be confirmed in future studies. Trial registration in PROSPERO database: CRD42018084055.

Endovascular therapy versus medical treatment for symptomatic intracranial artery stenosis

BACKGROUND

Intracranial atherosclerotic stenosis (ICAS) is an arterial narrowing in the brain that can cause stroke. Endovascular therapy and medical management may be used to prevent recurrent ischaemic stroke caused by ICAS. However, there is no consensus on the best treatment for people with ICAS.

OBJECTIVES

To compare the safety and efficacy of endovascular therapy (ET) plus conventional medical treatment (CMT) with CMT alone for the management of symptomatic ICAS.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (30 August 2019), Cochrane Central Register of Controlled Trials (CENTRAL: to 30 August 2019), MEDLINE Ovid (1946 to 30 August 2019), Embase Ovid (1974 to 30 August 2019), Scopus (1960 to 30 August 2019), Science Citation Index Web of Science (1900 to 30 July 2019), Academic Source Complete EBSCO (ASC: 1982 to 30 July 2019), and China Biological Medicine Database (CBM: 1978 to 30 July 2019). We also searched the following trial registers: ClinicalTrials.gov, WHO International Clinical Trials Registry Platform, and Stroke Trials Registry. We also contacted trialists and researchers where additional information was required.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing ET plus CMT with CMT alone for the treatment of symptomatic ICAS. ET modalities included angioplasty alone, balloon-mounted stent, and angioplasty followed by placement of a self-expanding stent. CMT included antiplatelet therapy in addition to control of risk factors such as hypertension, hyperlipidaemia, and diabetes.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened trials to select potentially eligible RCTs and extracted data. Any disagreements were resolved by discussing and reaching consensus decisions with the full team. We assessed risk of bias and applied the GRADE approach to assess the quality of the evidence. The primary outcome was death of any cause or non-fatal stroke of any type within three months of randomisation. Secondary outcomes included any-cause death or non-fatal stroke of any type more than three months of randomisation, ipsilateral stroke, type of recurrent event, death, restenosis, dependency, and health-related quality of life.

MAIN RESULTS

We included three RCTs with 632 participants who had symptomatic ICAS with an age range of 18 to 85 years. The included trials had high risks of performance bias and other potential sources of bias due to the impossibility of blinding of the endovascular intervention and early termination of the trials. Moreover, one trial had a high risk of attrition bias because of the high rate of loss of one-year follow-up and the high proportion of participants transferred from endovascular therapy to medical management. The quality of evidence ranged from low to moderate, downgraded for imprecision. Compared to CMT, ET probably results in a higher rate of 30-day death or stroke (risk ratio (RR) 3.07, 95% confidence interval (CI) 1.80 to 5.24; 3 RCTs, 632 participants, moderate-quality evidence), 30-day ipsilateral stroke (RR 3.54, 95% CI 1.98 to 6.33; 3 RCTs, 632 participants, moderate-quality evidence), 30-day ischaemic stroke (RR 2.52, 95% CI 1.37 to 4.62; 3 RCTs, 632 participants, moderate-quality evidence), and 30-day haemorrhagic stroke (RR 15.53, 95% CI 2.10 to 115.16; 3 RCTs, 632 participants, low-quality evidence). ET was also likely associated with a worse outcome in one-year death or stroke (RR 1.69, 95% CI 1.21 to 2.36; 3 RCTs, 632 participants, moderate-quality evidence), one-year ipsilateral stroke (RR 2.28, 95% CI 1.52 to 3.42; 3 RCTs, 632 participants, moderate-quality evidence), one-year ischaemic stroke (RR 2.07, 95% CI 1.37 to 3.13; 3 RCTs, 632 participants, moderate-quality evidence), and one-year haemorrhagic stroke (RR 10.13, 95% CI 1.31 to 78.51; 2 RCTs, 521 participants, low-quality evidence). There were no significant differences between ET and CMT in 30-day transient ischaemic attacks (TIA) (RR 0.52, 95% CI 0.11 to 2.35, P = 0.39; 2 RCTs, 181 participants, moderate-quality evidence), 30-day death (RR 5.53, 95% CI 0.98 to 31.17, P = 0.05; 3 RCTs, 632 participants, low-quality evidence), one-year TIA (RR 0.82, 95% CI 0.32 to 2.12; 2 RCTs, 181 participants, moderate-quality evidence), one-year death (RR 1.20, 95% CI 0.50 to 2.86, P = 0.68; 3 RCTs, 632 participants, moderate-quality evidence), and one-year dependency (RR 1.90, 95% CI 0.91 to 3.97, P = 0.09; 3 RCTs, 613 participants, moderate-quality evidence). No data on restenosis and health-related quality of life for meta-analysis were available from the included trials. Two RCTs are ongoing.

AUTHORS' CONCLUSIONS

This systematic review provides moderate-quality evidence showing that ET, compared with CMT, in people with recent symptomatic severe intracranial atherosclerotic stenosis probably does not prevent recurrent stroke and appears to carry an increased hazard. The impact of delayed ET intervention (more than three weeks after a qualifying event) is unclear and may warrant further study.

Endovascular Treatment of Intracranial Atherosclerotic Stenosis: Current Debates and Future Prospects

Intracranial atherosclerotic stenosis (ICAS) is a common cause of transient ischemic attack (TIA) and ischemic stroke. Endovascular treatment, including balloon angioplasty alone, balloon-mounted stents, and self-expandable stent placement with or without prior angioplasty, is an alternative to medical treatment for the prevention of recurrent TIA or ischemic stroke in patients with ICAS. Although the SAMMPRIS and VISSIT trials supported medical management alone against endovascular treatments, both randomized controlled trials (RCT) were criticized due to flaws relating to patient-, intervention-, and operator-related factors. In this review, we discuss the current debate regarding these aspects and suggest approaches to solve current controversies in the future. In our opinion, endovascular treatment in carefully selected patients, individualized choice of endovascular treatment subtypes, and an experienced multidisciplinary team managing the patient in the pre-, peri- and post-procedural period have the potential to provide safe and efficious treatment of patients with symptomatic ICAS.

Percutaneous Transluminal Angioplasty with Stent Placement versus Best Medical Therapy Alone in Symptomatic Intracranial Arterial Stenosis: A Best Evidence Review

Intracranial arterial stenosis (ICAS) is a common cause of stroke, and the risk of ischemic stroke from a stenotic intracranial artery remains high despite best medical therapy (BMT). As a result, clinicians have increasingly turned to percutaneous transluminal angioplasty and stenting (PTAS) over the last decade as an alternative therapy in high-risk patients with symptomatic ICAS. In this review, we will critically analyze multiple clinical trials to assess the safety and efficacy of PTAS with BMT versus BMT alone. The Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) trial reported a higher rate of stroke or death within 30 days in the PTAS plus BMT group (14.7%) than the BMT only group (5.8%, p = 0.002). The rate of any stroke during the follow-up period (mean = 32 months) was higher in the PTAS plus BMT group (22.3%) than the BMT only group (14.1%, p = 0.03). The Vitesse Intracranial Stent Study for Ischemic Stroke Therapy (VISSIT) trial reported a higher rate of stroke or death within 30 days in the PTAS plus BMT cohort (24.1%) than the BMT only cohort (9.4%, p = 0.05). There was also a higher rate of hard transient ischemic attack (TIA) or stroke within one year in the PTAS plus BMT group (36.2%) than the BMT only group (15.1%, p = 0.02). The Vertebral Artery Ischaemia Stenting (VIST) trial reported the rate of any stroke during the follow-up period to be two events in 50 person-years in the PTAS plus BMT cohort versus four events in 45 person-years in the BMT only cohort, with a calculated hazard ratio of 0.47 (p = 0.39). Vertebral Artery Stenting Trial (VAST) reported a higher incidence of stroke, MI, or vascular death in the PTAS with BMT cohort (22%) than the BMT only cohort (0%). Tang et al. reported no significant difference in the incidence of vascular events at one year and three years between the PTAS plus BMT and BMT only cohorts. However, the distribution of vascular events was more concentrated in the first postoperative week in the PTAS plus BMT cohort (75% of all vascular events) versus the BMT only cohort (17%). Feng et al. reported a lower periprocedural complication rate (9.1%) with the Enterprise stent in comparison to the Wingspan and balloon-expandable stents used in the SAMMPRIS and VISSIT trials. We conclude that PTAS should not be employed as first-line treatment in patients with symptomatic ICAS. However, PTAS should be considered in symptomatic ICAS patients that are hemodynamically unstable or have repeatedly failed BMT, especially at sites with lower rates of perioperative complications than those reported here.

Percutaneous transluminal angioplasty and stenting for symptomatic intracranial arterial stenosis: a systematic review and meta-analysis

OBJECTIVES

The cumulative safety and efficacy measures of percutaneous transluminal angioplasty and stenting (PTAS) for secondary stroke prevention in patients with symptomatic intracranial arterial stenosis (sICAS) have not previously been evaluated using a meta-analytical approach.

METHODS

We conducted a systematic review and random effects meta-analysis of all available randomized controlled trials (RCTs) evaluating the safety and efficacy of PTAS (in comparison with medical therapy) for sICAS.

RESULTS

Three RCTs (678 total patients) were included in the quantitative analysis. PTAS was associated with a higher risk of recurrent ischemic stroke in the territory of qualifying artery both within 30 days [risk ratio (RR) = 2.21, 95% confidence interval (CI) 1.10-4.43] and 1 year (RR = 1.92, 95% CI 1.10-3.36). PTAS was also related to a higher risk of any ischemic stroke within 30 days from the index event (RR = 2.08, 95% CI 1.17-3.71). The risk for intracranial hemorrhage was found to be higher in PTAS patients both within 30 days (RR = 10.60, 95% CI 1.98-56.62) and 1 year (RR = 8.15, 95% CI 1.50-44.34). The composite outcome of any stroke or death within 1 year (RR = 2.29, 95% CI 1.13-4.66) and 2 years (RR = 1.52, 95% CI 1.04-2.21) was higher in PTAS than in medical therapy. PTAS was associated with a higher risk of any stroke or death within 2 years in the sICAS subgroup located in posterior circulation (RR = 2.37, 95% CI 1.27-4.42).

CONCLUSIONS

PTAS is associated with adverse early and long-term outcomes and should not be recommended in patients with sICAS. Further research to identify subgroups of patients who could also serve as candidates for future interventional trials along with efforts to reduce procedure-related complications are needed.