| Part1 Safety and Feasibility of Frequency domain Optical Coherence Tomography(FD-OCT) to Evaluate Carotid Plaques Before and After Stent DeploymentBackground and Purpose: To evaluate the safety and feasibility of Frequency domain Optical Coherence Tomography(FD-OCT) in patients with carotid stenosis undergoing carotid artery stenting(CAS).Methods: Consecutive patients who underwent CAS with OCT imaging between Jan 2014 and May 2015 at a single center were retrieved from the prospectively maintained Nanjing Stroke Registry Program(NSRP) database. The patients underwent high-definition(homoaxial resolution 10 mm) OCT image acquisition before stent deployment and after stent placement(2 scans/patient). Pullbacks were started during a nonocclusive flush, mechanically injecting 15 m L of 100% diluted contrast at 8 m L/s to displace blood from the artery. Two independent physicians judged the quality of images on a predefined 1–10 scale. The proportions of specific agreement and kappa values( k) were calculated.Results: Twenty-two consecutive patients were enrolled and 40/44(90.9%) qualified images were got. No procedural or in-hospital neurological complications occurred(any stroke/ death 0%). No significant alteration in glomerular filtration rate or any other significant adverse event occurred. The images obtained were of high quality(mean value 7.5±0.9 out of 10), with good inter- and intraobserver agreement(κ=0.76 and κ=0.82, respectively; both p<0.001). OCT images revealed innovative features such as rupture of the fibrous cap, plaque prolapse, and stent malapposition in many patients.Conclusion: FD-OCT during a nonocclusive flush appears to be feasible and safe in carotid arteries. Since some original and unexpected information after CAS has been made available for the first time at such a high definition, future studies with OCT should focus on the interaction between carotid plaque and stent design, which might revolutionize our understanding of the mechanisms of carotid stenting.Part2 Intravascular Optical Coherence Tomography Assessment of Carotid Artery atherosclerosis in Symptomatic and Asymptomatic PatientsBackground and Purpose: The identification of asymptomatic patients with carotid disease who are at risk of stroke remains a challenge. There is an increasing awareness that plaque characteristics may best risk-stratify this population. The goal of this study was to investigate carotid plaque characteristics in symptomatic versus asymptomatic patients with the use of OCT.Methods: Consecutive patients who underwent CAS with OCT imaging between Jan 2014 and May 2015 at a single center were retrieved from the prospectively maintained Nanjing Stroke Registry Program(NSRP) database. Data analysis was carried out by imaging experts who were unaware of the clinical characteristics of the study population.Results: Fifty-two patients undergoing diagnostic carotid angiography were studied with OCT. Plaque with American Heart Association type VI complicated features was more common in symptomatic than asymptomatic patients(68.0% vs.33.3%, respectively; p=0.025). This was largely driven by differences in the incidence of microphage infiltration(52.0% vs. 22.2%, p =0.043) and thrombus(64.0% vs. 37.0%, p = 0.095). Conversely, firbrous plaque were more common in asymptomatic than symptomatic patients(40.0% vs. 70.4%, respectively; p = 0.050). Logistic regression analysis suggests type VI plaque and microphage infiltration are independent risk factors for the occur of symptoms of carotid artery atherosclerosis patient.Conclusion: This analysis of carotid OCT data supports the hypothesis that the evaluation of carotid plaque characteristics with this high-resolution imaging technique has the potential to alter the understanding and treatment of carotid artery disease.Part3 An Optical Coherence Tomography Assessment of Stent Strut Apposition Based on the Presence of Lipid-Rich Plaque in the Carotid ArteryBackground and 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 32 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.Part4 Application of OCT in observing acute thrombosis after carotid artery stenting and the literature review—a case reportAcute stent thrombosis is a rare complication of CAS, which will lead to severe neurologic deficits, influence surgery effect, even life threatening. OCT is an optical analogue of intravascular ultrasound that allows high-resolution tomographic intra-arterial imaging. In this case report, OCT has been shown to accurately identify acute thrombosis after CAS.Part5 Methodology, terminology and clinical applications of OCT for the assessment of interventional procedures in cerebral vesselsOCT, like intravascular ultrasound(IVUS) is changing the way we see cerebral vessel pathophysiology. The detail with which carotid artery pathophysiology is viewed by this intravascular imaging modality is unprecedented, such that we are only now just beginning to establish how this imaging information might be best used to guide management and influence patient outcomes. This review, therefore, describes the current status of carotid artery optical diagnosis with OCT, in what is already a rapidly evolving and dynamic field of intraartery imaging. |
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