Cerebral protection during carotid artery stenting: collection and histopathologic analysis of embolized debris

Current concepts of mechanical cerebral protection during precutaneous carotid intervention

Major advances in the endovascular treatment of carotid artery stenosis are underway, with an emphasis on improving the safety profile of the technique. This review highlights key areas in the concepts and design of available mechanical neuroprotection devices utilized during carotid stenting to minimize procedural cerebral embolization. The advantages and disadvantages of each system are explored and the available clinical experience is given. The size threshold of particulate material likely to be clinically relevant is examined and compared with pathological analysis of particles trapped by protection systems reported in the world literature. It is shown that the adverse neurological event rate in those protected is lower than that in historical studies of unprotected carotid stenting. Furthermore, the size range and numbers of particles trapped by protections systems are sufficient to cause potential neurological injury if allowed passage to the brain. Further improvements in outcomes may require further refinement of protection technology.

Recent developments in vascular surgery

The authors of this review discuss the changing role of vascular surgery and the impact of developments such as endovascular interventions and new techniques for treating varicose veins

Carotid angioplasty in a pulsatile flow model: factors affecting embolic potential

OBJECTIVES

Carotid endoluminal intervention is an alternative to surgery but carries a risk of embolic stroke even with distal protection devices. We investigated the clinical features and degree of stenosis related to number and size of emboli during carotid angioplasty.

DESIGN

An experimental ex vivo study.

MATERIALS

An ex vivo pulsatile flow model was used in which temperature, velocity, flow, pressure and viscosity characteristics were designed to simulate the carotid circulation.

METHODS

Carotid endarterectomy specimens excised as intact cylinders (n = 28) were subjected to a standardised angioplasty procedure using radiological guidance. Emboli collected in filters placed distally were counted and sized using microscopy.

RESULTS

Median number of emboli during angioplasty was 133 (range 15-1331). Median size of the largest embolus was 700 microns (range 75-2400). Severity of stenosis correlated with increased maximum size (r = 0.55, p = 0.012). Statin therapy >4 weeks pre-operatively was associated with reduced emboli number and size (54 (range 15-748) vs 247 (range 37-1331) [p = 0.023] and 400 microm (range 75-2400) vs 1300 microm (range 600-2200) [p = 0.022]).

CONCLUSIONS

In this model a wide range of emboli number and size were produced. Number and size of embolic particles were highest in patients with high-grade stenoses not receiving statin therapy.

Complications associated with stenting for cerebral arteries

SUMMARY

We have experienced total 116 stenting for 102 of cranio-cephalic arteries and 14 of intracranial arteries including occlusive cerebrovascular diseases, aneurysms, and fistulas.Ten complications were encountered. Three were ischemic complication, four stent migration, two restenosis, and one aneurysmal perforation during coiling across the stent strut. The mechanism and preventive method of these complications were discussed in this paper.

Clinical results of stenting for cervical internal carotid stenoses

SUMMARY

Total 89 patients with cervical ICA stenosis were treated by stenting. In 74 cases of stenting, we used our blocking balloon systems to prevent distal embolism. The morbidity and the mortality rate was 4.5% and 0%, respectively.Two(3%) of 74 cases showed distal embolism when blocking balloon catheter systems(BBCS) were used, while distal embolism occurred in four (27%) of 15 cases of stenting without BBCS. On diffusion- weighted MRI (DWI), hyperintense areas were detected in seven (47%) of 15 lesions when we used BBCS only during postdilatation. On the other hand, use of BBCS during predilatation as well as postdilatation reduced hyperintense areas on DWI, which were detected in three (25%) of 12 patients. Our blocking balloon catheter system is a useful device to reduce the risk of distal embolism, especially when we use it during not only postdilatation but predilatation.