A Follow-up Study of Cerebral Microbleeds in Patients Who Received Stents for Symptomatic Cerebral Artery Stenosis

Active drug-coated flow diverter in a preclinical model of intracranial stenting

BACKGROUND

Flow diverters carry the risk of thromboembolic complications (TEC). We tested a coating with covalently bound heparin that activates antithrombin to address TEC by locally downregulating the coagulation cascade. We hypothesized that the neuroimaging evidence of TEC would be reduced by the coating.

METHODS

16 dogs were implanted with overlapping flow diverters in the basilar artery, separated into two groups: heparin-coated (n=9) and uncoated (n=7). Following implantation, high-frequency optical coherence tomography (HF-OCT) was acquired to quantify acute thrombus (AT) formation on the flow diverters. MRI was performed postoperatively and repeated at 1, 2, 3, 4, and 8 weeks, consisting of T1-weighted imaging, time-0f-flight (ToF), diffusion weighted imaging (DWI), susceptibility weighted imaging (SWI), and fluid attenuated inversion recovery (FLAIR) sequences. Neurological examinations were performed throughout the 8-week duration of the study.

RESULTS

The mean AT volume on coated devices was lower than uncoated (0.014 vs 0.018 mm3); however, this was not significant (P=0.3). The mean number of foci of magnetic susceptibility artifacts (MSAs) on SWI was significantly different between the uncoated and coated groups at the 1-week follow-up (P<0.02), and remained statistically different throughout the duration of the study. The AT volume showed a direct linear correlation with the MSA count and 80% of the variance in the MSA could be explained by the AT volume (P<0.001). Pathological analysis showed evidence of ischemic injury at locations of MSA.

CONCLUSIONS

Heparin-coated flow diverters significantly reduced the number of new MSAs after 1 week follow-up, showing the potential to reduce TEC.

Safety and efficacy of the Low-Profile Visualized Intraluminal Support stent in treating intracranial atherosclerotic stenosis

PURPOSE

The performance of the Low-Profile Visualized Intraluminal Support (LVIS) stent deployed following balloon angioplasty is unknown in treating intracranial atherosclerotic stenosis, and this study was to investigate the safety and efficacy of the LVIS stent in treating intracranial atherosclerotic stenosis in the middle cerebral artery M1 segment.

METHODS

Thirty-five patients were enrolled with 35 atherosclerotic stenoses at the M1 segment. The stenosis was about 75% in 16 patients, 80% in 15, and 90% in the rest four. The LVIS stent was used to treat these patients.

RESULTS

The success rate of stenting was 97.1%. The stenting procedure was failed in one patient because of intraprocedural dissection of the stenotic (75%) segment, resulting in a 30-day periprocedural complication rate of 2.9% (1/35). Before stenting, the stenosis rate ranged 75%-90% (mean 78.9%±4.7%), and after stenting, the diameter of the stented segment was significantly (P<0.0001) increased to 1.5-3.4mm (mean 2.1±0.32mm) ranging 68.2%-100% (mean 94.0%±5.8%) of the normal arterial diameter, with the residual stenosis ranging 0-31.8% (median 4.8%, IQR 2.4%-7.3%). Follow-up was performed at 6-20 months (mean 8.5) after stenting. One patient (2.9%) had occlusion of the stented M1 segment with no symptoms, and two patients (5.7%) had slight asymptomatic instent stenosis (40%) at the M1 segment, with the instent restenosis and occlusion rate of 8.6% (3/35).

CONCLUSION

The braided LVIS stent can be safely applied for treatment of intracranial atherosclerotic stenosis in the middle cerebral artery with good safety and efficacy immediately after stenting and at follow-up.

Number of cerebral microbleeds after intracranial/extracranial stenting and dual antiplatelet therapy

BACKGROUND

Cerebral microbleeds (CMBs) are small (<1 cm) perivascular hemosiderin depositions. They may be visible in T2* or susceptibility-weighted magnetic resonance imaging (MRI) sequences. CMBs may indicate an increased risk of intracerebral hemorrhage (ICH) or vascular disease. Cerebral white matter changes indicate small vessel disease (SVD), which is also related to CMBs. In cerebral vascular treatment, dual antiplatelet therapy (DAPT) is routinely used after stenting. We surveyed our cerebral stenting case series for changes in the number of CMBs.

METHODS

Patients receiving extracranial or intracranial stenting between 2018 and 2020 were included. All patients received DAPT after stenting. Changes in CMBs, SVD degree, and other findings from pretreatment to follow-up MRI were recorded. Differences between stented artery supplying territory and other territories were compared.

RESULTS

The average age of the 75 enrolled patients was 65.37 years ± 11.53 (50 male and 25 female patients); 84 extracranial or intracranial stentings were performed. The average Fazekas scale score was 1.32 ± 0.77. Significantly more CMBs developed in the initial ≥6 CMB group than in the initial 0 and 1-5 CMB groups (7 ± 3.6 vs 0.56 ± 1.06, 1.45 ± 3.32, p < 0.001). No significant difference in increased CMBs was observed between the initial 0 and 1-5 CMB groups. Significantly more CMBs developed in the stented artery supplying territory than elsewhere (0.6 ± 0.13 vs 0.44 ± 0.17, p < 0.05). No ICH was noted in our case series.

CONCLUSION

Preexisting CMB was a risk factor for the onset of new CMBs after stenting and DAPT. Poststenting and DAPT statistically increased CMBs in stented artery supplying territories at short-term follow-up.

Safety and efficacy of the Low-Profile Visualized Intraluminal Support stent in treating intracranial atherosclerotic stenosis

PURPOSE

The performance of the Low-Profile Visualized Intraluminal Support (LVIS) stent deployed following balloon angioplasty is unknown in treating intracranial atherosclerotic stenosis, and this study was to investigate the safety and efficacy of the LVIS stent in treating intracranial atherosclerotic stenosis in the middle cerebral artery M1 segment.

METHODS

Thirty-five patients were enrolled with 35 atherosclerotic stenoses at the M1 segment. The stenosis was about 75% in 16 patients, 80% in 15, and 90% in the rest four. The LVIS stent was used to treat these patients.

RESULTS

The success rate of stenting was 97.1%. The stenting procedure was failed in one patient because of intraprocedural dissection of the stenotic (75%) segment, resulting in a 30-day periprocedural complication rate of 2.9% (1/35). Before stenting, the stenosis rate ranged 75%-90% (mean 78.9%±4.7%), and after stenting, the diameter of the stented segment was significantly (P<0.0001) increased to 1.5-3.4mm (mean 2.1±0.32mm) ranging 68.2%-100% (mean 94.0%±5.8%) of the normal arterial diameter, with the residual stenosis ranging 0-31.8% (median 4.8%, IQR 2.4%-7.3%). Follow-up was performed at 6-20 months (mean 8.5) after stenting. One patient (2.9%) had occlusion of the stented M1 segment with no symptoms, and two patients (5.7%) had slight asymptomatic instent stenosis (40%) at the M1 segment, with the instent restenosis and occlusion rate of 8.6% (3/35).

CONCLUSION

The braided LVIS stent can be safely applied for treatment of intracranial atherosclerotic stenosis in the middle cerebral artery with good safety and efficacy immediately after stenting and at follow-up.

Factors associated with the new appearance of cerebral microbleeds after endovascular treatment for unruptured intracranial aneurysms

PURPOSE

Endovascular treatment of unruptured intracranial aneurysms may increase cerebral microbleeds (CMBs) in postprocedural T2*-weighted MRIs, which may be a risk for future intracerebral hemorrhage. This study examined the characteristics of postprocedural CMBs and the factors that cause their increase.

METHODS

The patients who underwent endovascular treatment for unruptured intracranial aneurysms from April 2016 to February 2018 were retrospectively analyzed. Treatment techniques for endovascular treatment included simple coiling, balloon-assisted coiling, stent-assisted coiling, or flow diverter placement. To evaluate the increase in CMBs, a head MRI including diffusion-weighted imaging and T2*-weighted MRIs was performed on the preprocedural day; the first postprocedural day; and at 1, 3, and 6 months after the procedure.

RESULTS

Among the 101 aneurysms that were analyzed, 38 (37.6%) showed the appearance of new CMBs. In the multivariate analysis examining the causes of the CMB increases, chronic kidney disease, a higher number of preprocedural CMBs, and a higher number of diffusion-weighted imaging-positive lesions on the first postprocedural day were independent risk factors. Furthermore, a greater portion of the increased CMBs was found in cortical and subcortical lesions of the treated vascular perfusion area within 1 month after the procedure.

CONCLUSION

In endovascular treatment for unruptured intracranial aneurysms, CMBs tended to increase in patients with small vessel disease before the procedure, and it was also implicated in hemorrhagic changes after periprocedural microinfarction.

Advance of antithrombotic treatment in patients with cerebral microbleed

With the elder proportion increasing and the antithrombotic agents widely using as well as the newly magnetic resonance imaging sequence emerging, the detection rate of cerebral microbleed (CMB) is gradually raising in recent years. As we all know that CMB mainly reflects the severity of deeply small vessel lesions, which predicts hemorrhagic transformation. Whereby, to some patients with both CMB and remarkable antithrombotic indication, treatment becomes a dilemma. We have to face the challenge of weighing the pros and cons of both drug indication and bleeding risk when making a proper decision for patients. This study summarized recent advance on CMB diagnosis and treatment, to provide a useful reference to physicians in their clinical practice.