Long Term Outcome of In-Stent Stenosis after Stent Assisted Coil Embolization for Cerebral Aneurysm

High-resolution vessel wall imaging for quantitatively and qualitatively evaluating in-stent stenosis of intracranial aneurysms

Background

It is critical to accurately and noninvasively evaluate the stented parent artery of intracranial aneurysms (IAs) with endovascular treatment.

Objective

To investigate high-resolution vessel wall imaging (HR-VWI) for quantitative and qualitative evaluation of in-stent stenosis (ISS) in IAs treated with stent placement (SP).

Methods

Fifty-five patients (58 aneurysms) underwent HR-VWI, contrast-enhanced (CE)-HR-VWI, CE-MR angiography (MRA), time-of-flight (TOF)-MRA, and digital subtraction angiography (DSA) six months after SP, and the reliability of quantitative stent lumen measurements was evaluated by intraclass correlation coefficient (ICC) analysis. Agreement and correlation of quantitative evaluation were estimated by comparing the four MR imaging modalities with DSA. The diagnostic performance for >0%, ≥25%, and ≥50% of ISS degrees and overall diagnostic accuracy for the ISS degrees of the four MR imaging modalities were calculated to qualitative evaluation.

Results

The reliability of CE-HR-VWI and HR-VWI for ISS quantitative measurements was excellent (ICC 0.955-0.989). The agreement and correlation of CE-HR-VWI, HR-VWI versus DSA for ISS quantitative measurements were better than those of CE-MRA and TOF-MRA (p < 0.05). The diagnostic performance for distinguishing the degree of ISS >0%, ≥25%, and ≥50% by CE-HR-VWI and HR-VWI was superior to CE-MRA and TOF-MRA, and their overall diagnostic accuracy was 96.55 and 94.83%, respectively. HR-VWI and CE-HR-VWI were not statistically significant in the quantitative and qualitative evaluation of ISS performance (p > 0.05).

Conclusion

HR-VWI and CE-HR-VWI have similar performance and value in the quantitative and qualitative evaluation of ISS, and HR-VWI without contrast media could be used as an ideal long-term follow-up approach after SP treatment for IAs.

Comparative study on the clinical outcomes and prognosis of endovascular embolization and craniotomy clipping for the treatment of cerebral aneurysms

Objective

To investigate the safety and outcomes of endovascular embolization and craniotomy clipping in the treatment of cerebral aneurysms.

Methods

We collected the clinical data of 106 patients with cerebral aneurysm who underwent surgical treatment (endovascular embolization, Group-A, n=55; craniotomy clipping, Group-B, n=51) in the First People's Hospital of Yichang from January 2020 to May 2021. We compared surgical treatment indexes, treatment costs, neurological function before and after the treatment, incidence of postoperative complications and the prognosis after one-year follow-up between the two groups.

Results

Endovascular embolization (Group-A) was associated with a shorter mean operation time and hospital stay, a lower mean intraoperative bleeding amount, and a higher mean treatment cost than craniotomy clipping (Group-B) (P<0.05). Compared with the pre-operative neurological function scores, the scores of both groups decreased after the surgery, and the mean post-operative score of Group-A was significantly lower than that of Group-B (P<0.05). Compared with Group-B , patients in Group-A had a lower overall complication rate (P < 0.05. Higher proportion of patients in Group-A had a good prognosis (P < 0.05).

Conclusion

Endovascular embolization for the treatment of cerebral aneurysms is safe as it can shorten the operation time and hospital stay, reduce the incidence of neurological injury and complications, and have a favorable prognosis. However, the treatment is more expensive. Endovascular embolization can be selected for the treatment of cerebral aneurysms when economic conditions allow it.

Additional rescue stenting with Neuroform Atlas stents during stent-assisted coiling of saccular aneurysms

OBJECTIVE

Overlapping stenting is sometimes attempted during endovascular treatment of cerebral aneurysm as a rescue for coil herniation, stent mal-positioning, or in-stent thrombosis. We retrospectively evaluated the efficacy and safety of additional rescue stenting (ARS) in telescoping fashion with Neuroform Atlas stent (NAS) during stent-assisted coiling of saccular aneurysms.

METHODS

We collected clinical and radiological data of patients with saccular aneurysms treated with ARS using NASs between March 2018 and December 2021. Y or X-stent-assisted coiling technique was excluded.

RESULTS

Eighteen unruptured and 5 ruptured aneurysms in 23 patients were treated with ARS using NASs. Sizes of aneurysms ranged from 2.0 mm to 10.0 mm (mean: 5.0 mm). Immediate angiographic results were complete occlusion in 11 aneurysms, residual neck in 4 aneurysms, and residual sac in 8 aneurysms. Peri-operative morbidity was 4.3 %. Nineteen of 23 patients underwent follow-up conventional angiography (mean, 9.9 months). Results showed progressive occlusion in 10 (52.6 %) cases and asymptomatic in-stent stenosis in 3 (15.8 %) cases. At the end of the observation period (mean, 17.4 months), all 18 patients without subarachnoid hemorrhage had excellent clinical outcomes (mRS of 0), except one (mRS of 1). Of five patients with subarachnoid hemorrhage, four had a favorable outcome (mRS of 0-1), while the other one was dependent (mRS of 4).

CONCLUSION

In this report on 23 patients, ARS with NASs for treating saccular aneurysms showed good technical safety with favorable clinical and angiographic outcomes. However, delayed in-stent stenosis was not uncommon. Thus, regular imaging follow-up is required.

The incidence and predictors of in-stent stenosis after pipeline flow-diverter stenting for intracranial aneurysm treatment

Background and purpose

Data on in-stent stenosis (ISS) following the flow diverter (FD) implantation method are scarce and inconsistent. In the present study, we sought to determine the incidence of ISS and identify the factors that predict its severity via the use of ordinal logistic regression.

Methods

A retrospective review of our center's electronic database was conducted to identify all patients with intracranial aneurysms (IAs) who received pipeline embolization device (PED) implantation between 2016 and 2020. Patient demographics, aneurysm characteristics, procedural information, and clinical and angiographic outcomes were reviewed. ISS was quantitatively assessed on angiographic follow-ups and graded as mild (<25%), moderate (25-50%), or severe (>50%). Ordinal logistic regression was conducted to determine the predictors of stenosis severity.

Results

A total of 240 patients with 252 aneurysms treated in 252 procedures were enrolled in this study. ISS has been detected in 135 (53.6%) lesions, with a mean follow-up time of 6.53 ± 3.26 months. The ISS was mild in 66 (48.9%) cases, moderate in 52 (38.5%) cases, and severe in 17 (12.6%) cases. All patients were asymptomatic, except for two of them with severe stenosis who presented with symptoms of acute cerebral thrombosis. Ordinal logistic regression identified that younger age and a longer procedure duration were independent predictors of a higher likelihood of ISS.

Conclusion

ISS is a common angiographic finding after PED implantation for IAs and is presented as a largely benign course through long-term follow-up. Patients who were younger in age and had a longer procedure duration were found to be at a greater risk of developing ISS.

Effects of stent-assisted coiling in comparison with flow diversion on intracranial aneurysms

Objective

The aim of this study was to investigate the efficacy and complications of stent-assisted coiling in comparison with flow diversion for wide-necked intracranial aneurysms.

Methods

Patients with wide-necked intracranial aneurysms who were treated with stent-assisted coiling or flow diversion were respectively, enrolled into the stent-assisted coiling or flow diversion treatment group. The clinical and angiographic data were analyzed.

Results

A total of 61 patients with intracranial aneurysms underwent stent-assisted coiling, including 35 (57.4%) female and 26 (42.6%) male patients with 21 (34.4%) ruptured and 40 (65.6%) unruptured aneurysms. Also, 53 patients underwent deployment of flow-diverting devices, including 30 (56.6%) female and 23 (43.4%) male patients with 25 (47.2%) ruptured and 28 (52.8%) unruptured aneurysms. Stent-assisted coiling was performed successfully in 60 patients with 63 stents deployed, and immediate aneurysm occlusion was complete occlusion in 38 (62.3%) aneurysms, residual neck in 12 (19.7%), and residual aneurysm in 10 (16.4%). Procedure-related complications included in-stent thrombosis in three (4.9%) patients, coil protrusion in three (4.9%), and re-rupture of one (1.6%) aneurysm, with a total complication rate of 11.5%. In the flow diversion group, a pipeline embolization device alone was deployed in each of the 24 (45.3%) patients, adjunctive coiling combined with a pipeline device in 29 (54.7%), and double pipeline devices in each of the 6 (11.3%) patients. Immediately after treatment, complete occlusion was achieved in 3 (5.7%) patients with adjunctive coiling, residual neck in 3 (5.7%), and residual aneurysm in 47 (88.7%). Procedure-related complications included aneurysm rebleeding in one patient (1.9%). Clinical and angiographic follow-up was performed 13–49 months (median 29) after the procedure for 49 (80.3%) patients with stent-assisted coiling, with complete aneurysm occlusion in 27 (55.1%) aneurysms, residual neck in 3 (6.1%), residual aneurysm in 5 (10.2%), and recurrence in 14 (28.6%). Follow-up was performed for 14–37 (median 25) months in 45 (84.9%) patients with flow diversion treatment, with complete occlusion in 39 (86.7%) patients, residual neck in 5 (11.1%), residual aneurysm in 1 (2.2%), and no aneurysm recurrence.

Conclusions

Stent-assisted coiling comes with more complications but fewer permanent aneurysm occlusions than flow diverters, and flow diverters are superior to stent-assisted coiling in the treatment of wide-necked intracranial aneurysms, especially in the long-term effect.

Bifurcated Aneurysm Location Predicts In-Stent Stenosis After Neuroform-EZ Stent-Assisted Coiling for Intracranial Aneurysm

Background and Purpose

The Neuroform EZ stent system (Boston Scientific Corporation, Fremont, CA, United States) is a fourth-generation intracranial aneurysm stent designed specifically for the cerebrovasculature to support aneurysm treatment. In this study, we analyzed our consecutive series of patients with aneurysm treated with the Neuroform EZ stent, with special attention to the occurrence of in-stent stenosis (ISS).

Methods

A retrospective review of our center's electronic database was conducted to identify all patients with intracranial aneurysms who underwent aneurysm treatment with the Neuroform EZ stent between January 2016 and October 2018. Patients with at least one digital subtraction angiography (DSA) follow-up in our hospital were enrolled in this study. In-stent stenosis (ISS) was graded as mild (<2–5%), moderate (25–50%), or severe (>50%).

Results

The study included 114 patients (78 women, 68.4%; median age 57.2 ± 9 years) with a total of 116 aneurysms. Of the 116 lesions, 20 were identified with ISS (17.2%) at a mean follow-up of 6.9 ± 1.7 months, and ISS was mild in 30% (6/20), moderate in 50% (10/20), and severe in 20% (4/20). No patients were symptomatic or required further intervention. Patients who developed ISS were younger than those without ISS (52.6 ± 7.8 vs. 57.9 ± 9; p = 0.016). The proportion of aneurysms located at the artery bifurcation was significantly higher in patients with stenosis than located at the sidewall artery (37.9 vs. 10.3%; p = 0.002). In the multivariable analysis, the patients' age (OR = 0.94; 95% CI 0.88–0.998; p = 0.02) and bifurcated aneurysm location (OR = 4.59; 95% CI 1.54–13.67; p = 0.006) were independent predictors of ISS.

Conclusions

In this retrospective study, the incidence of ISS after Neuroform EZ stent placement was 17.2%, and all the ISS cases were asymptomatic. Patients with younger age and bifurcated aneurysm location are more likely to develop ISS. Although Neuroform EZ stent is particularly suitable for bifurcated aneurysms, the ISS for this location should be focused upon.

Imaging Intracranial Aneurysms in the Endovascular Era: Surveillance and Posttreatment Follow-up

While most intracranial aneurysms (IAs) remain asymptomatic over a patient's lifetime, those that rupture can cause devastating outcomes. The increased usage and quality of neuroimaging has increased detection of unruptured IAs and driven an increase in surveillance and treatment of these lesions. Standard practice is to treat incidentally discovered unruptured IAs that confer high rupture risk as well as ruptured IAs to prevent rehemorrhage. IAs are increasingly treated with coil embolization instead of microsurgical clipping; more recently, flow diversion and intrasaccular flow disruption have further expanded the versatility and utility of endovascular IA treatment. Imaging is increasingly used for posttreatment IA follow-up in the endovascular era. While cerebral angiography remains the standard for IA characterization and treatment planning, advances in CT and CT angiography and MR angiography have improved the diagnostic accuracy of noninvasive imaging for initial diagnosis and surveillance. IA features including size, dome-to-neck ratio, location, and orientation allow rupture risk stratification and determination of optimal treatment strategy and timing. The radiologist should be familiar with the imaging appearance of common IA treatment devices and the expected imaging findings following treatment. In distinction to clipping and coil embolization, flow diversion and intrasaccular flow disruption induce progressive aneurysm obliteration over months to years. Careful assessment of the device; the treated IA; adjacent brain, bone, meninges; and involved extracranial and intracranial vasculature is crucial at posttreatment follow-up imaging to confirm aneurysm obliteration and identify short-term and long-term posttreatment complications. An invited commentary by Chatterjee is available online. Online supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article. ^©RSNA, 2022.

Neurotoxicity of Paclitaxel and Rapamycin in a Rat Model with Transient Blood-Brain Barrier Opening

Objective

Drug-eluting stents and balloons are occasionally used to reduce restenosis in medically intractable intracranial atherosclerotic stenosis. The authors aimed to determine whether such drugs can cause neurotoxicity due to local effects in a rat model.

Methods

Intra-arterial catheters were placed in the right common carotid artery of rats. Mannitol was injected to transiently open the brain-blood barrier (BBB), followed by high-dose drug (paclitaxel and rapamycin) injection. The optimal time interval of transient BBB opening for maximal drug penetration was determined to be 10 minutes. Paclitaxel and rapamycin were intraarterially administered in various doses. All the rats were neurologically evaluated, and their brain tissues were histologically examined.

Results

Neither neurological deficits nor histological abnormalities were observed in all the rats.

Conclusion

Paclitaxel and rapamycin did not cause neurotoxicity in a rat model with transient BBB opening.

Short- and Long-Term Safety and Efficacy of Self-Expandable Leo Stents Used Alone or with Coiling for Ruptured and Unruptured Intracranial Aneurysms: A Retrospective Observational Study

To assess the efficacy and safety of the Leo stent used alone or with coiling to treat complex intracranial aneurysms (IAs) not eligible for simple or balloon-assisted coiling, this single-center retrospective study included consecutive adults with ruptured or unruptured IAs treated in 2011-2018 by stenting with or without coiling. The indication for stenting was IA complexity precluding simple or balloon-assisted coiling. Extensive data on the patients, IAs, antiplatelet treatments, procedures, and outcomes over the first 36 months were collected. Risk factors for early complications (univariate analysis) and delayed ischemia (multivariate analysis) were sought. We include 64 patients with 66 IAs. The procedural success rate was 65/66 (98.5%). Obliteration was Raymond Roy class I or II for 85% of IAs. Six patients died including four of the 12 patients presenting with subarachnoid hemorrhage, which was the only significant risk factor for early major complications. At 1 month, 45/64 (69%) had no disabilities. No rebleeding was reported. Ischemia was detected by routine MRI in 20 (35%) of the 57 patients with long-term data and was asymptomatic in 14. The stent-within-a-stent configuration was the only independent risk factor for ischemia. The Leo stent used alone or with coils to manage challenging IAs was associated with a high procedural success rate and complete or nearly complete IA obliteration of 85% of IAs. The high frequency of ischemia is ascribable to our use of routine serial MRI. In patients with bleeding, the Leo stent was associated with an excess risk of early, major, intracranial complications, as compared to patients without bleeding. Long-term follow-up was marked by the occurrence of ischemic events in the vascular territory of the stent, mostly silent.

Usefulness of black-blood magnetic resonance angiography generated from vessel wall imaging after the stent-assisted treatment of intracranial arterial diseases

PURPOSE

After stent-assisted treatment for intracranial diseases, three-dimensional time-of-flight magnetic resonance angiography is a noninvasive follow-up method, but susceptibility artifacts prevent accurate evaluations of stented arteries. Sampling perfection with application-optimized contrast using different flip angle evolution (SPACE) sequence often used for vessel wall imaging is less susceptible to susceptibility artifacts, since it is a spin-echo sequence. Hence, we evaluated the feasibility of black-blood magnetic resonance angiography generated from vessel wall imaging data obtained using the SPACE sequence in the depiction of stented arteries by comparing with three-dimensional time-of-flight magnetic resonance angiography and digital subtraction angiography.

METHODS

Our study group comprised 11 consecutive patients. For both three-dimensional time-of-flight magnetic resonance angiography and black-blood magnetic resonance angiography, the contrast ratio obtained from the stented artery and the normal artery proximal to the stent were calculated. And the depiction of stented arteries was visually evaluated. Additionally, the relative diameter index obtained from the stented artery and the normal artery proximal to the stent were calculated for three-dimensional time-of-flight magnetic resonance angiography, black-blood magnetic resonance angiography and digital subtraction angiography.

RESULTS

The contrast ratio of the stented artery was significantly lower than that of the normal artery on three-dimensional time-of-flight magnetic resonance angiography, but no significant difference was seen using black-blood magnetic resonance angiography. Regarding both the diameter index and the visual assessment score, black-blood magnetic resonance angiography was significantly better than three-dimensional time-of-flight magnetic resonance angiography. On black-blood magnetic resonance angiography, the diameter index was equal to that of digital subtraction angiography, and the flow signal was homogeneous and continuous in most the cases.