Short- and long-term hemodynamic and clinical effects of carotid artery stenting

Clinical Outcomes of Second- versus First-Generation Carotid Stents: A Systematic Review and Meta-Analysis

Background: Single-cohort studies suggest that second-generation stents (SGS; “mesh stents”) may improve carotid artery stenting (CAS) outcomes by limiting peri- and postprocedural cerebral embolism. SGS differ in the stent frame construction, mesh material, and design, as well as in mesh-to-frame position (inside/outside). Objectives: To compare clinical outcomes of SGS in relation to first-generation stents (FGSs; single-layer) in CAS. Methods: We performed a systematic review and meta-analysis of clinical studies with FGSs and SGS (PRISMA methodology, 3302 records). Endpoints were 30-day death, stroke, myocardial infarction (DSM), and 12-month ipsilateral stroke (IS) and restenosis (ISR). A random-effect model was applied. Results: Data of 68,422 patients from 112 eligible studies (68.2% men, 44.9% symptomatic) were meta-analyzed. Thirty-day DSM was 1.30% vs. 4.11% (p < 0.01, data for SGS vs. FGS). Among SGS, both Casper/Roadsaver and CGuard reduced 30-day DSM (by 2.78 and 3.03 absolute percent, p = 0.02 and p < 0.001), whereas the Gore stent was neutral. SGSs significantly improved outcomes compared with closed-cell FGS (30-day stroke 0.6% vs. 2.32%, p = 0.014; DSM 1.3% vs. 3.15%, p < 0.01). At 12 months, in relation to FGS, Casper/Roadsaver reduced IS (−3.25%, p < 0.05) but increased ISR (+3.19%, p = 0.04), CGuard showed a reduction in both IS and ISR (−3.13%, −3.63%; p = 0.01, p < 0.01), whereas the Gore stent was neutral. Conclusions: Pooled SGS use was associated with improved short- and long-term clinical results of CAS. Individual SGS types, however, differed significantly in their outcomes, indicating a lack of a “mesh stent” class effect. Findings from this meta-analysis may provide clinically relevant information in anticipation of large-scale randomized trials.

Persistent Hemodynamic Depression After Carotid Artery Stenting: A Review and Update

According to the American Heart Association, ischemic stroke is the second leading cause of death globally and is responsible for approximately 11% of deaths. Carotid endarterectomy (CEA) is the standard treatment for moderate or severe extracranial internal carotid artery (ICA) stenoses. With the development of materials and technology in neurointervention, the Centers for Medicare and Medicaid Services (CMS) have proposed that carotid artery stenting (CAS) can serve as an alternative treatment for CEA. As CAS is widely used worldwide, comorbidities, especially persistent hemodynamic depression (PHD) and stroke, have attracted public attention. In this review, we summarized the current advances in PHD after CAS. A better understanding of CAS-related PHD may inspire the design of potential prognostic and therapeutic tools.

NSE, S100B and MMP9 Expression Following Reperfusion after Carotid Artery Stenting

Objective:

Previous studies have shown that the neuron-specific- enolase (NSE), S100B protein (S100B) and matrix metalloproteinase-9 (MMP9) are specific markers for studying cerebral injury. This study was aimed to demonstrate these biomarkers for their correlation with reperfusion after carotid artery stenting (CAS).

Methods:

In this study, a total of 44 patients who were diagnosed unilateral carotid artery stenosis by digital subtraction angiography (DSA) and underwent CAS, were selected as the operation groups. The patients' blood samples were collected at three different time points: T1, prior to operation; T2, next morning after operation (24 hours); T3, three days after operation (72 hours); All of the patients with the operation received computed tomography perfusion (CTP) at T1 and T3. The second group of 12 patients, who were excluded for carotid artery stenosis by DSA, were assigned to be the control group; Blood samples of these patients were collected at T1. The concentrations of NSE, S100B and MMP9 in serum from patients of both groups were detected by ELISA.

Results:

All of the operations were implanted in stents successfully without complications. (1) After CAS, rCBF increased while rMTT and rTTP decreased. (2) The concentrations of NSE, S100B and MMP9 in the serum decreased gradually (T1>T2>T3). There was no significant difference between the control group and the operation group at T1 (P>0.05) on their concentrations of NSE, S100B and MMP9 in the serum. When compared among the operation groups, the concentrations of NSE, S100B and MMP9 in the serum at T1 and T3 showed significant difference (P < 0.05). (3) Correlation analysis among the operation groups indicated that NSE, S100B, MMP9 and rCBF were positively correlated before operation (r = 0.69, 0.58 and 0.72, respectively, P < 0.05), as well as after operation (r = 0.75, 0.65 and 0.60, respectively, P < 0.05).

Conclusion:

We concluded that the concentrations of NSE, S100B and MMP9 in serum decreased with the improvement of cerebral reperfusion after CAS. NSE, S100B and MMP9 can be used as laboratory biochemical markers to evaluate the improvement of reperfusion after CAS. The results very well complement the imaging methods, such as CTP.

Carotid stenting for unilateral stenosis can increase contralateral hemispheric cerebral blood flow

BACKGROUND

The revascularization of carotid stenosis can increase ipsilateral cerebral blood flow (CBF). Occasionally, elevated CBF is also evident on the contralateral side, but this phenomenon is poorly understood.

OBJECTIVE

To analyze retrospectively the relationship between a contralateral CBF increase and several clinical and radiologic features.

MATERIALS AND METHODS

We retrospectively analyzed 40 patients with unilateral cervical carotid stenosis treated by carotid artery stenting (CAS). Using ¹²³I-iodamphetamine single-photon emission computed tomography (SPECT); we compared pre- and postoperative hemispheric CBF on both sides. We investigated the influence of the following five factors on the increase of the contralateral hemispheric CBF: stenosis grade (≥50% or <50%, according to the North American Symptomatic Carotid Endarterectomy Trial criteria); age; the presence of anterior and posterior communicating arteries; postoperative hyperperfusion on the stenotic side; and the presence of cerebral steal phenomenon during preoperative acetazolamide-challenge SPECT.

RESULTS

Following unilateral CAS, mean hemispheric CBF increased significantly on both sides: from 33.4±5.6 (mean ± SD) to 38.7±7.8 mL/min on the operated side (paired t test, p<0.001) and f35.4±5.4 to 39.2±7.2 mL/min on the contralateral side (p<0.001). In a general linear model, stenosis grade (≥50%) alone was significantly correlated with the increase of the CBF on the contralateral side (p=0.03).

CONCLUSION

Revascularization by CAS for unilateral carotid stenosis can increase hemispheric CBF on both sides. Increase of the contralateral CBF is correlated with stenosis grade (≥50%).

Intracranial Blood Flow Changes in Patients with High-Grade Severe Carotid Artery Stenosis After Stenting

OBJECTIVE

We investigated whether the cerebral hemodynamic changes of pre- and poststenting in patients with severe carotid stenosis differ by stenosis grades.

METHODS

We prospectively recruited patients who underwent carotid artery stenting (CAS) after acute ischemic stroke from June 2014 to December 2015. We compared the mean relative cerebral blood flow (rCBF) changes (measured by whole-brain computed tomography perfusion) pre- and poststenting in patients with high-grade severe stenosis (HGSS) (90%-99%) versus patients with low-grade severe stenosis (LGSS) (70%-89%).

RESULTS

Among 24 patients included in the study (mean age, 66.2 ± 7.2 years; 91.7% men), 62.5% (15/24) were in the HGSS group and 37.5% (9/24) were in the LGSS group. In the HGSS group, rCBF increased in territories of the anterior cerebral artery (P = 0.021), middle cerebral artery (P < 0.001), posterior cerebral artery (P = 0.001), and basil ganglia (P = 0.003) after stenting. Of the patients with HGSS, 53.3% (8/15) had collateral flow through anterior communicating artery (AcomA) prestenting. After stenting, all the AcomA collaterals in HGSS reverted to normal (P = 0.002).

CONCLUSIONS

The improvement of brain perfusion combined with the normalization of collateral flow through the circle of Willis after CAS was observed only in patients with HGSS.

Loss of labelling efficiency caused by carotid stent in pseudocontinuous arterial spin labelling perfusion study

AIM

To elucidate the cause of cerebral hypoperfusion on the stent placement side after carotid artery stent placement (CAS) measured by pseudocontinuous arterial spin labelling (PCASL) perfusion imaging.

MATERIALS AND METHODS

Consecutive patients with symptomatic internal carotid artery stenosis receiving CAS were included in the study. Cerebral blood flow (CBF) was measured by PCASL perfusion imaging at 3 T magnetic resonance imaging (MRI) the day before and 3 days after the procedure. Changes in cerebral haemodynamics after CAS were assessed.

RESULTS

Twenty-two patients were included; 17 patients had increased or stationary CBF after CAS and five patients had significantly reduced CBF on the stenting side after CAS whereas CBF increased on the contralateral side. High stent position was noticed in the five patients. After labelling plane adjustment to avoid labelling on the stent, no more cerebral hypoperfusion was noticed.

CONCLUSION

When using PCASL perfusion imaging to monitor post-stenting CBF, the stent may cause an artefact that leads to a low CBF in the territory of the stented vessel. Routinely adding a fast T2 star gradient-echo echo-planar-imaging covering the upper neck region before PCASL perfusion imaging to identify the stent position and avoid the stent-related artefact is recommended.

Decreased ¹³N-labeled ammonia uptake in the ipsilateral and contralateral hemispheres following carotid endarterectomy

Carotid artery plaques are a leading cause of ischemic stroke, and carotid endarterectomy (CEA) is one of the major treatment approaches for this disease. Changes in cerebral metabolism following CEA remain unclear. The present study aimed to evaluate the effect of cerebral ammonia metabolism following CEA using ¹³N-labeled ammonia positron emission tomography (PET) in humans. A total of 20 patients were enrolled in the present study, with a mean age of 59.5 years, comprising 16 males and four females. Of these patients, eight underwent right CEA and 12 underwent left CEA. The rate of carotid artery stenosis was between 50–69% in six of the patients, between 70–99% in 11 of the patients and was at 100% (thrombosis) in three of the patients, measured by computerised tomography digital subtraction angiography prior to CEA. ¹³N-labeled ammonia (137 MBq) PET scanning was performed prior and subsequent to CEA surgery for each patient. The first ammonia PET scan was performed 1 day prior to CEA, while the second PET scan was performed 1–4 weeks following CEA. Following injection of ¹³N-labeled ammonia, static PET was acquired for 10 min. The region of interest (ROI), covering the major cerebral hemisphere, was selected and ammonia uptake in the ROI was determined in the ipsilateral and contralateral hemispheres. No hyperperfusion syndrome was observed in the patients subsequent to CEA. No significant change in cerebral hemisphere ammonia uptake was observed between the ipsilateral and contralateral hemispheres prior to (ratio =0.98; P>0.01) or following (ratio =1.09; P>0.01) CEA. Ammonia uptake in the ipsilateral and contralateral hemispheres was significantly reduced to 23.2 and 23.5%, respectively, following CEA. Using ¹³N-labeled ammonia PET to evaluate cerebral ammonia metabolism following CEA in patients with severe carotid artery stenosis, the present study demonstrated that uptake of ammonia in the ipsilateral and contralateral hemispheres was significantly reduced.