Influence of Vertebrobasilar Stenotic Lesion Rigidity on the Outcome of Angioplasty and Stenting

Percutaneous transluminal angioplasty and stenting for severe stenosis of the intracranial carotid artery and its branches: Comparison of the Wingspan stent vs the Credo stent

BACKGROUND

Despite the widespread use of the Wingspan stent system for treating severe medically refractory intracranial artery stenosis (SMR-ICAS), a new Credo stent system was approved because it could integrate stent delivery within the balloon catheter. However, the therapeutic outcomes of these two systems have not been compared. This preliminary study aimed to compare the results of percutaneous angioplasty and stenting (PTAS) in SMR-ICAS patients treated with either Wingspan or Credo stents within the anterior cerebral circulation.

METHODS

SMR-ICAS patients with >70% stenosis in the anterior circulation who underwent PTAS using either the Wingspan or Credo stent system were retrospectively analyzed. We evaluated the technical success, safety, and outcomes of the two-stent systems.

RESULTS

A total of 29 patients were analyzed, including 17 patients treated with Wingspan stents and 12 with Credo stents. The outcomes of the Wingspan stent vs Credo stent were as follows: technical success (16/17 [94%] vs 11/12 [92%], p = 1.00); periprocedural intracranial hemorrhage (2/17 [12%] vs 0/12 [0%], p = 0.50); silent embolic ischemic lesions on periprocedural magnetic resonance imaging (MRI) (13/17 [76%] vs 7/12 [58%], p = 0.42); and significant (>50%) in-stent restenosis in 1 year (4/17 [24%] vs 2/12 [17%], p = 1.00). No recurrent stroke or mortality was noted within 30 days after the procedures or during the 1-year follow-up period.

CONCLUSION

The technical success, safety, and outcomes of the Credo stent system were comparable to those of the Wingspan stent system in the management of SMR-ICAS patients. Further large-scale studies are warranted to substantiate these findings.

Association between vascular calcification in intracranial vertebrobasilar circulation and luminal stenosis

INTRODUCTION

The study aims to assess the correlation and association between calcium burden and luminal stenosis in the vertebrobasilar circulation.

METHODS

We evaluated 166 patients [mean age, 79.8 ± 8.8 (SD) with 93 males] with stroke symptoms. The calcification patterns were assessed on non-contrast CT (NCCT); quantitative calcium burden [Agatston-Janowitz (AJ) calcium score, volume, and mass] on the initial non-contrast phase of CT perfusion (CTP); and the qualitative and quantitative luminal stenosis on CT angiography (CTA) studies. We calculated the correlation coefficient and association between measures of calcium burden and luminal stenosis.

RESULTS

Two hundred twenty-eight of 498 arteries (45.8%) had detectable calcification on NCCT and measurable stenosis in 169 of 498 arteries (33.9%) on CTA. We found a moderate correlation between qualitative calcium burden and qualitative (0.51 for R1 and 0.62 for R2, p < 0.01) as well as quantitative luminal stenosis (0.67 for R1 and 0.69 for R2, p < 0.01). There was a moderate correlation of AJ score (0.66), volume (0.68), and mass of calcification (0.60, p < 0.01) with luminal stenosis measurements. The quantitative calcium burden and luminal stenosis showed statistically significant differences between different qualitative categories of calcium burden (p < 0.001 in both readers). However, severe stenosis was not seen even with the advanced circumferential wall calcification (mean stenosis of 35.3-40.7%).

CONCLUSION

Our study showed a moderate correlation between higher burden of vascular calcification and the degree of luminal stenosis. However, higher calcium burden and circumferential wall calcification were not associated with severe luminal stenosis.

A Smart Stent for Monitoring Eventual Restenosis: Computational Fluid Dynamic and Finite Element Analysis in Descending Thoracic Aorta

Even though scientific studies of smart stents are extensive, current smart stents focus on pressure sensors. This paper presents a novel implantable biocompatible smart stent for monitoring eventual restenosis. The device is comprised of a metal mesh structure, a biocompatible and adaptable envelope, and pair-operated ultrasonic sensors for restenosis monitoring through flow velocity. Aside from continuous monitoring of restenosis post-implantation, it is also important to evaluate whether the stent design itself causes complications such as restenosis or thrombosis. Therefore, computational fluid dynamic (CFD) analysis before and after stent implantation were carried out as well as finite element analysis (FEA). The proposed smart stent was put in the descending thoracic section of a virtually reconstructed aorta that comes from a computed tomography (CT) scan. Blood flow velocity showed that after stent implantation, there is not liquid retention or vortex generation. In addition, blood pressures after stent implantation were within the normal blood pressure values. The stress and the factor of safety (FOS) analysis showed that the stress values reached by the stent are very far from the yield strength limit of the materials and that the stent is stiff enough to support the applied loads exported from the CFD results.

Prediction of Infarct Growth and Neurological Deterioration in Patients with Vertebrobasilar Artery Occlusions

We aimed to identify predictors of infarct growth and neurological deterioration (ND) in vertebrobasilar occlusions (VBOs) with a focus on clinical-core mismatch. From 2010 to 2018, VBO patients were selected from a university hospital registry. In total, 138 VBO patients were included. In these patients, a posterior circulation Alberta Stroke Program Early CT score (PC-ASPECTS) less than 6 was associated with futile outcome. Within patients with feasible cores, a decrease in PC-ASPECTS score of 2 or more on follow-up imaging was classified as infarct growth and could be predicted by a National Institutes of Health Stroke Scale (NIHSS) mental status subset of 1 or higher (odds ratio (OR): 3.34, 95% confidence interval (CI) (1.19-9.38), p = 0.022). Among the 73 patients who did not undergo reperfusion therapy, 13 patients experienced ND (increase in discharge NIHSS score of 4 or more compared to the initial presentation). Incomplete occlusion (vs. complete occlusion, OR 6.17, 95% CI (1.11-34.25), p = 0.037), poorer collateral status (BATMAN score, OR: 1.91, 95% CI (1.17-3.48), p = 0.009), and larger infarct cores (PC-ASPECTS, OR: 1.96, 95% CI (1.11-3.48), p = 0.021) were predictive of ND. In patients with VBO, an initial PC-ASPECTS of 6 or more, but with a decrease in the mental status subset of 1 or more can predict infarct growth, and may be used as a criterion for clinical-core mismatch. ND in VBO patients presenting with milder symptoms can be predicted by incomplete occlusion, poor collaterals, and larger infarct cores.