An Optical Coherence Tomography Assessment of Stent Strut Apposition Based on the Presence of Lipid-Rich Plaque in the Carotid Artery.

PURPOSE

To evaluate the rate of stent malapposition, plaque prolapse, and fibrous cap rupture detected by optical coherence tomography (OCT) after carotid artery stenting (CAS) based on the presence of lipid-rich plaque, which may be associated with acute stent thrombosis.

METHODS

A retrospective study was conducted involving 26 consecutive patients who underwent CAS with OCT imaging acquired before stent deployment and after stent dilation. Adequate imaging quality could not be obtained in 6 patients (out-of-screen images and residual blood), which left 20 patients (mean age 63 years; 13 men) for analysis. Plaque characteristics were determined from 500 selected OCT cross sections; a lipid-rich plaque was defined by lipid present in ≥2 quadrants. Cross-sectional OCT images within the stented segment were evaluated at 1-mm intervals for the presence of malapposition, plaque prolapse, and fibrous cap rupture. The data were compared between patients with and without lipid-rich plaques. The patients were examined at 6 months to determine the degree of in-stent restenosis (ISR).

RESULTS

Patients with lipid-rich plaque demonstrated a higher rate of embedded stent struts (29.4% vs 23.7%, p<0.001) and a lower rate of well apposed struts (54.6% vs 59.6%, p<0.001) compared to patients with non-lipid-rich plaque. Rates of plaque prolapse (65.5% vs 49.1%, p<0.001) and fibrous cap rupture (65.5% vs 49.1%, p<0.001) were significantly higher in patients with lipid-rich plaque. ISR ranged from none to 42% in 12 patients; malapposed stent struts and fibrous cap ruptures were not more frequent in the patients with obvious ISR. The 8 patients with no obvious restenosis still had malapposed struts, embedded struts, plaque prolapse, and fibrous cap rupture.

CONCLUSION

Embedded stent struts, plaque prolapse, and fibrous cap rupture were more frequent and well-apposed stent struts were less frequent after CAS in patients with lipid-rich plaque.