Depiction of the Vasa Vasorum during Carotid Endarterectomy by Intraoperative Videoangiography

Vasa Vasorum Densities in Human Carotid Atherosclerosis Is Associated with Plaque Development and Vulnerability

Objective

The extensive vasa vasorum network functions as a conduit for the entry of inflammatory cells or factors that promote the progression of angiogenesis and plaque formation. Therefore, we investigated the correlation between the carotid vasa vasorum activities and carotid plaque vulnerability using indocyanine green video angiography (ICG-VA) during carotid endarterectomy (CEA).

Methods

Sixty-nine patients who underwent CEA were enrolled prospectively from September 2015 to December 2017. During CEA, a bolus of ICG was injected intravenously before and after resecting the atheroma. Additionally, we performed immunohistochemistry using CD68 (a surface marker of macrophages), CD117 (a surface marker of mast cells), and CD4 and CD8 (surface markers of T-cells) antibodies to analyze the resected plaque specimens.

Results

The density of active vasa vasorum was observed in all patients using ICG-VA. The vasa vasorum externa (VVE) and interna (VVI) were seen in 11 (16%) and 57 patients (82.6%), respectively. Macroscopically, the VVE-type patterns were strongly associated with preoperative angiographic instability (81.8%, p=0.005) and carotid plaque vulnerability (90.9%, p=0.017). In contrast, the VVI-type patterns were weakly associated with angiographic instability (31.6%) and plaque vulnerability (49.1%). CD68-stained macrophages and CD117-stained mast cells were observed more frequently in unstable plaques than in stable plaques (p<0.0001, p=0.002, respectively).

Conclusion

The early appearance of VVE, along with the presence of many microvessel channels that provided nutrients to the developing and expanding atheroma during ICG-VA, was strongly associated with unstable carotid plaques. The degree of infiltration of macrophages and mast cells is possibly related to the formation of unstable plaques.

Identification of plaque location using intraoperative indocyanine green during carotid endarterectomy for patient with near occlusion

BACKGROUND

Microscope-integrated near-infrared indocyanine green (ICG) videoangiography (VA) is an effective method of intraoperative blood-flow assessment and identification of plaque location during carotid endarterectomy (CEA). However, the validity of ICG-VA during CEA for patient with near occlusion has not been elucidated.

METHODS

Thirty-four CEA procedures were performed between June 2009 and December 2017 for patient with near occlusion, which are more than 95% stenosis. The lesions were classified into three groups according to the diameter of distal ICA compared with ipsilateral external carotid artery (ECA), as normal diameter (>100%), moderate diameter reduction (50-100%), severe diameter reduction (<50%). Five mg of ICG was injected intravenously before arteriotomy, and ICG-VA was taken to identify the distal end of the plaque. Depiction of the distal end and its accuracy were retrospectively reviewed.

RESULTS

There were 18 cases with normal diameter group, 14 cases with moderate diameter reduction group, and 2 cases with severe diameter reduction group. All but one case in the severe diameter reduction group showed apparent distal end signal which were confirmed by arteriotomy afterward.

CONCLUSIONS

The present study clearly denotes that ICG-VA can visualize the carotid plaque distal end during the CEA, even with the patient with near occlusion. However, it should be noted that there may be a difficulty in visualization of the distal plaque end for patient with severely collapsed distal ICA.

Non-invasive imaging techniques and assessment of carotid vasa vasorum neovascularization: Promises and pitfalls

Carotid adventitia vasa vasorum neovascularization (VVn) is associated with the initial stages of arteriosclerosis and with the formation of unstable plaque. However, techniques to accurately quantify that neovascularization in a standard, fast, non-invasive, and efficient way are still lacking. The development of such techniques holds the promise of enabling wide, inexpensive, and safe screening programs that could stratify patients and help in personalized preventive cardiovascular medicine. In this paper, we review the recent scientific literature pertaining to imaging techniques that could set the stage for the development of standard methods for quantitative assessment of atherosclerotic plaque and carotid VVn. We present and discuss the alternative imaging techniques being used in clinical practice and we review the computational developments that are contributing to speed up image analysis and interpretation. We conclude that one of the greatest upcoming challenges will be the use of machine learning techniques to develop automated methods that assist in the interpretation of images to stratify patients according to their risk.

Intracranial artery to artery spontaneous revascularization in a child

INTRODUCTION

Intracranial artery-to-artery antegrade revascularization is a poorly recognized entity, more so when it involves main stem arteries. The etiology, appearance, and significance of this condition are not described in the literature.

CASE PRESENTATION

We describe a case of spontaneous revascularization of a chronically occluded middle cerebral arterial branch by collaterals from the proximal segment reconstituting distal flow, mimicking a brain arteriovenous malformation in a 9-year old boy. We discuss the nature of these channels, presumed to be related to artery to artery collaterals that are either dilated adventitial vasa vasorum, or, more likely, leptomeningeal collaterals that are hypertrophied in response to cerebral demand. We review the literature regarding intracerebral vasa vasorum and leptomeningeal collaterals including their imaging.

CONCLUSION

Recognizing the tortuous channels associated with this type of vascular abnormality as normal vessels reconsituting distal flow may prevent unnecessary and potentially dangerous treatments.