Optical coherence tomography for elucidation of flow-diversion phenomena: The concept of endothelized mural thrombus behind reversible in-stent stenosis in flow-diverters

Purpose Flow-diverters have revolutionized the endovascular treatment of intracranial aneurysms, offering a durable solution to aneurysms with high recurrence rates after conventional stent-assisted coiling. Events that occur after treatment with flow-diversion, such as in-stent stenosis (ISS) are not well understood and require further assessment. After assessing an animal model with Optical Coherence Tomography (OCT), we propose a concept that could explain the mechanism causing reversible ISS after treatment of intracranial aneurysms with flow-diverters. Methods Six Pipeline Flex embolization devices (PED-Flex), six PED with Shield technology (PED-Shield), and four Solitaire AB devices were implanted in the carotid arteries (two stents per vessel) of four pigs. Intravascular optical coherence tomography (OCT) and digital subtraction angiography (DSA) images obtained on day 21 were compared to histological specimens. Results A case of ISS in a PED-Flex device was assessed with OCT imaging. Neointima with asymmetrical topography completely covering the PED struts was observed. Histological preparations of the stenotic area demonstrated thrombus on the surface of device struts, covered by neointima. Conclusion This study provides a plausible concept for reversible ISS in flow-diverters. Based on an observation of a previous experiment, we propose that similar cases of ISS are related to thrombus presence underneath endothelization, but further experiments focused on this phenomenon are needed. Optical Coherence Tomography will be useful tool when available for clinical use.

Abstract 13750: Cardiac Magnetic Resonance to Predict Coronary Artery Compression in Patients Undergoing Transcatheter Pulmonary Valve Implantation Into Conduits

Introduction: Transcatheter pulmonary valve implantation (TPVi) is a widely available option to treat right ventricular outflow tract (RVOT) conduits, but coronary artery compression is an absolute contraindication. Cardiac magnetic resonance (CMR) may evaluate coronary anatomy, but its utility in predicting coronary compression is not well established. Hypothesis: CMR prior to TPVi can accurately predict coronary compression risk. Methods: We analyzed all patients with a recent CMR (≤ 12 months) and attempted TPVi in an RVOT conduit at 9 centers from 2007-2016. A core lab reviewed all CMRs for the shortest orthogonal distance from a coronary artery to the conduit, the shortest distance from a coronary artery to the most stenotic area of the conduit, and subjective assessment of coronary compression risk. Receiver operating characteristic curve was used to determine optimal predictive distances. Univariate and independent associations of the distances and qualitative assessment with coronary compression were examined using logistic regression. Results: Of 231 patients (62% male, median age 19.0 years), TPVi was successful in 198 (86%); in 24 (10%) balloon testing (documented coronary compression or high risk) precluded implantation. Distance to the RV to PA conduit ≤ 2.1 mm (area under the curve [AUC] 0.70) and distance to most stenotic area ≤ 13.1 mm (AUC 0.69) predicted coronary compression (Table). Subjective assessment had the highest AUC (0.78), with 96% negative predictive value. Both distances and qualitative assessment remained independently associated with coronary compression when controlling for abnormal coronary anatomy. Conclusions: CMR can predict the risk of coronary compression during TPVi in RVOT conduits but cannot completely exclude the risk of coronary compression. CMR may assist in patient selection and counselling families prior to TPVi, although balloon testing prior to TPVi remains essential.

Cutaneous microcirculation in patients with peripheral arterial occlusive disease: Comparison of capillary blood circulation in the nail fold of finger and toe

In patients with peripheral arterial occlusive disease (PAOD) a restricted circulation in cutaneous microvessels has been reported. In this study the velocity of erythrocytes (very) in finger nailfold capillaries - a vascular area without upstream macroangiopathy - and also in toe nailfold capillaries - a post-stenotic area –was investigated using capillary microscopy in apparently healthy subjects and patients with PAOD. Already in finger nailfold capillaries very of patients with PAOD under resting conditions was significantly lower than in capillaries of healthy subjects. This was also true for the circulation in toe capillaries. In addition, the erythrocyte velocities under resting conditions in the toe capillaries were significantly lower than in the finger capillaries. Similar results were found for the duration and the maximum velocity of postocclusive hyperemia. It is concluded that the resting blood flow in the skin microcirculation is impaired in PAOD patients, both under resting conditions and during postocclusive hyperemia in finger as well in toe nailfold capillaries.

Preoperative retrograde reintubation during partial tracheal resection and anastomosis in a cat with severe tracheal stenosis

A seven-month-old European shorthair cat was presented with dyspnoea and expiratory stridor due to a severe obstructive tracheal stenosis. Surgical resection of the stenotic area and anastomosis of the remaining parts of the trachea were performed. The anaesthetic management of a patient during tracheal resection is an anaesthetic challenge. Total intravenous anaesthesia with propofol and a continuous rate infusion of fentanyl were chosen to maintain a surgical anaesthetic depth and to ensure pain control. Endotracheal extubation was necessary at a specific time during the surgical procedure. However, subsequent oral reintubation was complicated, due to patient positioning and the presence of laryngeal spasms. Reintubation was only successful by means of a modified retrograde intubation technique. Recovery was satisfactory and uneventful.

The association of the circle of Willis anomaly and risk of stroke in patients with carotid artery disease

ABSTRACT The circle of Willis is an important collateral system that maintains perfusion to the stenotic area from the contralateral carotid and basilar artery to the region of reduced brain perfusion. The aim of the present study was to compare the circle of Willis anomaly in patients with unilateral symptomatic and asymptomatic carotid artery disease. Results In this retrospective study, we analyzed 175 patients who presented at our outpatient stroke clinic between January, 2013 and June, 2015 with either unilateral symptomatic or asymptomatic carotid artery disease, and who had had CT angiography imaging performed. Demographic properties, carotid artery stenosis and the anomaly of the circle of Willis was recorded. Conclusion There was no statistically significant difference in patients with symptomatic and asymptomatic carotid artery disease in terms of the anomaly of the circle of Willis.

Angiographic Characteristics of Radiation-Induced Carotid Arterial Stenosis

Purpose This study aimed to clarify the angiographic characteristics of radiation-induced carotid stenosis. Methods We evaluated 11 carotid arteries of patients after radiotherapy (radiotherapy group) and 26 carotid arteries of age- and gender-matched patients without a history of radiotherapy (control group). All patients had carotid stenosis detected by digital subtraction angiography (DSA). We developed an original coordinate system on the DSA to determine the accurate length and location of the carotid lesion. Results Radiation-induced carotid lesions were significantly longer than carotid lesions caused by atherosclerosis. The maximal stenosis of radiation-induced carotid lesions tended to be at the end of the stenotic area and within a wider range than the nonradiation-induced lesions, including in the proximal common carotid artery (CCA). Conclusions Radiation-induced stenotic lesions seem to exist in a wide range of carotid artery, including the CCA, along the vessel, and show maximal stenosis near the end of the stenotic area.