Carotid Artery Stenting Without Embolic Protection Device: A Single-Center Experience

PURPOSE

To evaluate the safety and efficacy of carotid artery stenting (CAS) performed without an embolic protection device (EPD) in a selected group of asymptomatic patients with primary internal carotid artery (ICA) stenosis or restenosis after carotid endarterectomy (CEA).

MATERIALS AND METHODS

Between May 2015 and May 2018, 77 patients (mean age 77 years; 60 men) underwent CAS without any embolic protection device. Forty-seven (61%) patients had primary ICA stenosis and were excluded from CEA because of high surgical risk; the other 30 (39%) patients had post-CEA restenosis (n=26) or a distal ICA flap after eversion CEA (n=4). The mean ICA stenosis was 82%. All procedures were performed from a femoral artery access. Pre- and/or postdilation were used in 64 patients. The primary outcome was the incidence of major complications (death, stroke, or myocardial infarction) during the procedure and within 30 days; the secondary outcome was the incidence of restenosis in follow-up.

RESULTS

No relevant bradycardia was encountered during CAS. The combined rate of stroke, death, or myocardial infarction at 30 days was 1.3%. The single stroke patient recovered fully after 2 months. Over a follow-up that ranged to 3 years (mean 24±18 months), no further neurological events were recorded. One (1.3%) patient had a >70% restenosis after 6 months; the lesion was dilated, successfully restoring the lumen contour.

CONCLUSION

In our series, endovascular treatment of carotid stenosis without the use of protection devices in patients with primary stenosis or postsurgical restenosis can achieve satisfactory safety and efficacy outcomes. The choice of performing CAS without using EPDs should follow a tailored approach based on the appropriate patient anatomy and specific clinical parameters to minimize neurological complications.

Evaluation of Fibrous Cap Rupture of Atherosclerotic Carotid Plaque with Thin-Slice Source Images of Time-of-Flight MR Angiography

OBJECTIVE

To investigate the ability of source image of time-of-flight magnetic resonance angiography (TOF-MRA) in the detection of fibrous cap rupture of atherosclerotic carotid plaques.

MATERIALS AND METHODS

From the database of radiological information in our hospital, 35 patients who underwent carotid MR imaging and subsequent carotid endoarterectomy within 2 weeks were included in this retrospective study. MR imaging included thin-slice time-of-flight MR angiography, black-blood T1- and T2-weighted imaging. Sensitivity, specificity and accuracy were calculated for the detection of fibrous cap rupture with source image of TOF-MRA. The Cohen k coefficient was also calculated to quantify the degree of concordance of source image of TOF-MRA with histopathological data.

RESULTS

Sensitivity, specificity and accuracy in the detection of fibrous cap rupture were 90% (95%CI: 81-98), 69% (95%CI: 56-82) and 79% (95%CI: 71-87) with a k value of 0.59. The false positives (n = 15) were caused by partial-volume averaging between fibrous cap and lumen at the shoulder of carotid plaque. The false negatives (n = 5) were underestimated as partial thinning of fibrous cap.

CONCLUSION

Source image of TOF-MRA can be useful in the detection of fibrous cap rupture with high sensitivity, but further technical improvement should be necessary to overcome shortcomings causing image degradation.

MR plaque imaging of the carotid artery

Atherosclerotic carotid plaque represents a major cause of cerebral ischemia. The detection of vulnerable plaque is important for preventing future cardiovascular events. The key factors in advanced plaque that are most likely to lead to patient complications are the condition of the fibrous cap, the size of the necrotic core and hemorrhage, and the extent of inflammatory activity within the plaque. Magnetic resonance (MR) imaging has excellent soft tissue contrast and can allow for a more accurate and objective estimation of carotid wall morphology and plaque composition. Recent advances in MR imaging techniques have permitted serial monitoring of atherosclerotic disease evolution and the identification of intraplaque risk factors for accelerated progression. The purpose of this review article is to review the current state of techniques of carotid wall MR imaging and the characterization of plaque components and surface morphology with MR imaging, and to describe the clinical practice of carotid wall MR imaging for the determination of treatment plan.