Caliber of Intracranial Arteries as a Marker for Cerebral Small Vessel Disease

Comparative study of plaque surface temperature and blood heat transfer in a stenosed blood vessel with different symmetrical configurations

The presence of macrophage cells inside plaque can lead to a change in plaque temperature, which can be measured by using arterial wall thermographic techniques to predict the severity of stenosis in the vessel without complicated surgery. This study aims to analyze the effect of plaque symmetricity with a similar degree of stenosis (DOS) on plaque surface temperature and blood heat transfer in a straight vessel. This analysis aims towards predicting the severity of stenosis in a straight blood vessel through plaque temperature as an indicator. Two cases are being analyzed here; case 1 and case 2 refer to having similar vessel dimensions and an overall degree of stenosis (DOS) of 70%, with the exception of case 1 having a symmetrically developed plaque while case 2 refers to an asymmetrically developed plaque. Euler-Euler multiphase method with the application of the granular model is being applied in this study. At peak systole (0.2 s into the 10th cardiac cycle) in a cardiac cycle, the increase in plaque surface temperature at exit is higher in case of a symmetrically developed stenosis compared to an asymmetric one but the reverse situation happens during end systole (0.5 s into the 10th cardiac cycle). Although the population of macrophages in a plaque is a deciding factor of the thermal signature of a plaque, the symmetricity variation also needs to be taken into consideration while plaque progression is being diagnosed through thermographic technique.

Patient outcomes after treatment of brain aneurysm in small diameter vessels with the silk vista baby flow diverter: A systematic review

BACKGROUND

The Silk Vista Baby (SVB, BALT) is a first-in-class flow-diverter device delivered using a 0.017" microcatheter, designed for the treatment of intracranial aneurysms, including those in small diameter vessels. This study reports a systematic literature review (SLR) to evaluate the safety and efficacy of using SVB to treat intracranial aneurysms in vessels less than 3.5 mm in diameter.

METHODS

We performed a PRISMA-compliant SLR to evaluate the outcomes of SVB in the treatment of aneurysms in small intracranial vessels. Primary outcomes were occlusion status and major stroke, and secondary outcomes included all-cause mortality, procedure-related neurologic death, and post-operative aneurysm rupture. Data were expressed as descriptive statistics only.

RESULTS

A total of four studies, including 163 patients with 173 intracranial aneurysms, were included. The most common aneurysm locations were the anterior cerebral artery (24.9% [43/173]), the middle cerebral artery (24.3% [42/173]), and the anterior communicating artery (23.1% [40/173]). Parent artery diameter ranged from 0.9 mm to 3.6 mm, and 29% were acutely or previously ruptured aneurysms. Overall, complete or near-complete occlusion was 72.1% on early-term follow-up. Mortality rate among the studies was 2.5%, with 3 instances adjudicated as neurologic deaths (1.8%). Major stroke was noted in 1.2% of cases, and branch occlusion or stent thrombus formation in 5.5%.

CONCLUSION

Our review suggests that SVB is a safe and effective treatment for intracranial aneurysms in small vessels. Further prospective and comparative studies with patient outcome data specific to aneurysm location are needed to confirm the safety and efficacy of SVB.

Toward a novel soft robotic system for minimally invasive interventions

PURPOSE

During minimally invasive surgery, surgeons maneuver tools through complex anatomies, which is difficult without the ability to control the position of the tools inside the body. A potential solution for a substantial portion of these procedures is the efficient design and control of a pneumatically actuated soft robot system.

METHODS

We designed and evaluated a system to control a steerable catheter tip. A macroscale 3D printed catheter tip was designed to have two separately pressurized channels to induce bending in two directions. A motorized hand controller was developed to allow users to control the bending angle while manually inserting the steerable tip. Preliminary characterization of two catheter tip prototypes was performed and used to map desired angle inputs into pressure commands.

RESULTS

The integrated robotic system allowed both a novice and a skilled surgeon to position the steerable catheter tip at the location of cylindrical targets with sub-millimeter accuracy. The novice was able to reach each target within ten seconds and the skilled surgeon within five seconds on average.

CONCLUSION

This soft robotic system enables its user to simultaneously insert and bend the pneumatically actuated catheter tip with high accuracy and in a short amount of time. These results show promise concerning the development of a soft robotic system that can improve outcomes in minimally invasive interventions.

Chitinase-3 like-protein-1, matrix metalloproteinase -9 and positive intracranial arterial remodelling

Introduction

Positive intracranial arterial remodelling is a dilated lesion of the large intracranial vessels; however, its pathogenesis is currently unknown. Some studies have identified chitinase-3 like-protein-1 (YKL-40) and matrix metalloproteinase (MMP)-9 as circulating inflammatory factors involved in positive vascular remodelling. Herein, we aimed to investigate the relationship between changes in serum YKL-40 and MMP-9 levels and positive intracranial arterial remodelling in patients with cerebral small vessel disease (CSVD).

Methods

A total of 110 patients with CSVD were selected. Patients with brain arterial remodelling (BAR) scores >1 times the standard deviation were defined as the positive intracranial artery remodelling group (n = 21 cases), and those with BAR scores ≤1 times the standard deviation were defined as the non-positive intracranial artery remodelling group (n = 89 cases). Serum YKL-40 and MMP-9 levels were measured using an enzyme-linked immunosorbent assay kit. Factors influencing positive intracranial artery remodelling using binary logistic regression analysis and predictive value of YKL-40 and MMP-9 for positive intracranial arterial remodelling in patients with CSVD were assessed by a subject receiver operating characteristic curve.

Results

Statistically significant differences in serum YKL-40 and MMP-9 levels were observed between the positive and non-positive remodelling groups (p < 0.05). The integrated indicator (OR = 9.410, 95% CI: 3.156 ~ 28.054, P<0.01) of YKL-40 and MMP-9 levels were independent risk factors for positive intracranial arterial remodelling. The integrated indicator (OR = 3.763, 95% CI: 1.884 ~ 7.517, p < 0.01) of YKL-40 and MMP-9 were independent risk factors for positive arterial remodelling in posterior circulation, but were not significantly associated with positive arterial remodelling in anterior circulation (p > 0.05). The area under the curve for YKL-40 and MMP-9 diagnostic positive remodelling was 0.778 (95% CI: 0.692–0.865, p < 0.01) and 0.736 (95% CI: 0.636–0.837, p < 0.01), respectively.

Discussion

Elevated serum YKL-40 and MMP-9 levels are independent risk factors for positive intracranial arterial remodelling in patients with CSVD and may predict the presence of positive intracranial arterial remodelling, providing new ideas for the mechanism of its occurrence and development and the direction of treatment.

Matrix metalloproteinase-2 and matrix metalloproteinase-9 serum levels in patients with vertebrobasilar dolichoectasia with and without stroke: case-control study

PURPOSE

To describe the differences in the serum levels of MMP-2 and MMP-9 of patients with vertebrobasilar dolichoectasia (VBD) with and without acute stroke.

METHODS

Case-control study. From an outpatient clinic, we recruited 14 controls and 19 patients with VBD. We also recruited 33 patients with stroke from two emergency departments, 14 without VBD (S/-VBD) and 19 with VBD (S/ + VBD). All the patients underwent serum MMP-2 and MMP-9 measurements and a non-contrast CT scan. Two investigators assessed the intracranial vertebral arteries (VA) and the basilar artery (BA) at the mid-pons. Diagnosis of VBD was made if the BA diameter was ≥ 4.5 mm.

RESULTS

The mean age of the 66 patients studied was 57.6 + 16.0 years, 41% female. In the 33 patients with stroke, the median NIHSS was 8 (range 15); there were no differences in the NIHSS scores between both groups with stroke. Median MMP-2 levels were lower in the S/-VBD when compared to controls. Median MMP-9 serum levels were higher in both groups with VBD when compared to controls and the S/-VDB group. Both groups with stroke exhibited higher MMP-9 serum levels than controls but were not statistically different from those found in patients with VBD. Serum levels of MMP-9 were significantly correlated with the diameters of the BA (r = 0.344, p = 0.01) and the left VA (r = 0.305, p = 0.05).

CONCLUSION

This study found that high serum levels of MMP-9 are associated with VBD independently of stroke and correlated with the degree of VBD.