Objective:To investigate and summarize the imaging and pathological features of non-acute occlusion following flow diverter (FD) implantation in animal models.Methods:Four experimental pigs (experimental group) that experienced non-acute occlusion (occlusion time exceeding 24 hours) within the FD stent implanted in the common carotid artery, and 19 pigs (control group) that did not experience stent occlusion during the same period were involved. Using an interventional approach under digital subtraction angiography (DSA), the 4 occluded FD lumens were mechanically opened. Optical coherence tomography (OCT), intravascular ultrasound (IVUS) and histopathological examinations were performed to evaluate the intraluminal composition and characteristics of the occlusive tissues. These findings were compared with non-occluded FD stents to summarize the imaging and pathological changes within the occluded FD lumen.Results:The occlusion times of the FD stents in the 4 experimental pigs were 16 weeks, 20 weeks, 20 weeks, and 24 weeks postoperatively. All occluded stents were successfully recanalized under DSA, with a technical success rate of 4/4. Among the 19 non-occluded FD stents, OCT and IVUS revealed uniform (16 stents) or non-uniform (3 stents) neointimal coverage of the stent struts, presenting as homogeneous high/slightly high signal intensity or medium echogenicity. Histopathological examination indicated that the neointima was primarily composed of smooth muscle cells and a small amount of fibrous connective tissues. In contrast, the 4 occluded FD stents demonstrated excessive neointimal proliferation and plaque formation, leading to luminal loss, as shown by OCT and IVUS. The occlusion tissues predominantly presented as homogeneous high signal intensity with weak attenuation (fibrous plaques) on OCT, with some regions showing blurred low signal intensity and strong attenuation (lipid plaques). IVUS presented homogeneous echogenicity (fibrous plaques) and hypoechogenic zones (lipid plaques). Histopathological examination showed that the occlusion tissues mainly consisted of smooth muscle cells, fibrous connective tissues, and lipids, accompanied by numerous foam cells and a minor presence of inflammatory cells.Conclusions:Histopathological examinations confirm that non-acute occlusion of FD is mainly caused by excessive hyperplasia of intima along with the formation of fibrous plaques and lipid plaques. OCT and IVUS have typical finding in imaging that can assist in determining the cause of stent occlusion as well as the lesion's nature, thereby providing crucial guidance for subsequent clinical treatment and drug selection.

Objective:To investigate and summarize the imaging and pathological features of non-acute occlusion following flow diverter (FD) implantation in animal models.Methods:Four experimental pigs (experimental group) that experienced non-acute occlusion (occlusion time exceeding 24 hours) within the FD stent implanted in the common carotid artery, and 19 pigs (control group) that did not experience stent occlusion during the same period were involved. Using an interventional approach under digital subtraction angiography (DSA), the 4 occluded FD lumens were mechanically opened. Optical coherence tomography (OCT), intravascular ultrasound (IVUS) and histopathological examinations were performed to evaluate the intraluminal composition and characteristics of the occlusive tissues. These findings were compared with non-occluded FD stents to summarize the imaging and pathological changes within the occluded FD lumen.Results:The occlusion times of the FD stents in the 4 experimental pigs were 16 weeks, 20 weeks, 20 weeks, and 24 weeks postoperatively. All occluded stents were successfully recanalized under DSA, with a technical success rate of 4/4. Among the 19 non-occluded FD stents, OCT and IVUS revealed uniform (16 stents) or non-uniform (3 stents) neointimal coverage of the stent struts, presenting as homogeneous high/slightly high signal intensity or medium echogenicity. Histopathological examination indicated that the neointima was primarily composed of smooth muscle cells and a small amount of fibrous connective tissues. In contrast, the 4 occluded FD stents demonstrated excessive neointimal proliferation and plaque formation, leading to luminal loss, as shown by OCT and IVUS. The occlusion tissues predominantly presented as homogeneous high signal intensity with weak attenuation (fibrous plaques) on OCT, with some regions showing blurred low signal intensity and strong attenuation (lipid plaques). IVUS presented homogeneous echogenicity (fibrous plaques) and hypoechogenic zones (lipid plaques). Histopathological examination showed that the occlusion tissues mainly consisted of smooth muscle cells, fibrous connective tissues, and lipids, accompanied by numerous foam cells and a minor presence of inflammatory cells.Conclusions:Histopathological examinations confirm that non-acute occlusion of FD is mainly caused by excessive hyperplasia of intima along with the formation of fibrous plaques and lipid plaques. OCT and IVUS have typical finding in imaging that can assist in determining the cause of stent occlusion as well as the lesion's nature, thereby providing crucial guidance for subsequent clinical treatment and drug selection.

Objective:To summarize the imaging features of severe unilateral transverse sinus and sigmoid sinus thromboses, and evaluate the efficacy and safety of intravascular interventional therapy in them.Methods:Thirty-seven patients with severe unilateral transverse sinus and sigmoid sinus thromboses clinically mainly manifested as intracranial hypertension and accepted endovascular intervention in Department of Interventional Radiology, First Affiliated Hospital of Zhengzhou University from June 2012 to September 2022 were chosen; their clinical data were retrospectively analyzed and imaging features were summarized. Short-term efficacy was evaluated according to blood flow restoration degrees and pressure gradient reduction in the occlusive sinus and modified neurological symptoms before and after endovascular intervention. Hospitalized complications were observed; safety and long-term efficacy were evaluated according to postoperative clinical follow-up and imaging results 6-12 months after endovascular intervention.Results:(1) Preoperative brain MRI and (or) CT showed different degrees of swelling of the brain tissues, with the affected side as the target; mixed signals/density shadow could be seen in the blocked transverse sinus and sigmoid sinus; venous cerebral infarction or post-infarction cerebral hemorrhage could be combined in some patients. MRV, CTV and DSA showed poor or completely occluded transverse sinus and sigmoid sinus while normal in the contralateral side; obvious thrombus filling-defect was observed in the occluded venous sinus after mechanical thrombolysis. (2) Occlusive sinus blood flow was restored in all patients after endovascular intervention, and pressure gradient of the occlusive segment decreased from (16.6±3.3) mmHg before to (2.8±0.8) mmHg after endovascular intervention. Before discharge, clinical symptoms of all patients were significantly improved (modified Rankin scale [mRS] scores of 0 in 30 patients, 1 in 5 patients, 2 in 1 patient and 3 in 1 patient), and 2 patients had unilateral limb movement disorder (muscle strength grading III and IV, respectively). All patients received clinical follow-up for (9.6±3.0) months. At the last follow-up, neurological function obviously improved compared with that before endovascular intervention, without new neurosystem-related symptoms (mRS scores of 0 in 30 patients, 1 in 6, and 2 in 1 patient). In 34 patients received MRV or DSA follow-up, 28 had complete recanalization of occlusive sinus and 6 had partial recanalization, without obvious stenosis or recurrent occlusion.Conclusions:Severe unilateral transverse sinus and sigmoid sinus thrombosis can cause local intracranial venous blood stasis, and then cause "increased regional venous sinus pressure", which is manifested as unilateral brain tissue swelling and even venous cerebral infarction or post-infarction cerebral hemorrhage. Early diagnosis and endovascular intervention can obviously improve the prognosis of these patients, enjoying good safety.

Objective:To investigate the application value of optical coherence tomography (OCT) and intravascular ultrasound (IVUS) in evaluating flow diverter (FD) apposition and endothelialization in aneurysm animal models, and analyze the effect of incomplete stent apposition (ISA) on aneurysm lumen healing and stent endothelialization.Methods:Lateral common carotid artery aneurysm models in swines were established by surgical method and then FD was implanted. Immediately after surgery, OCT and IVUS were used to evaluate the locations and degrees of ISA, and difference between these 2 methods in evaluating FD apposition was compared. DSA was performed at 12 weeks after surgery to evaluate the aneurysm occlusion (Kamran grading) and stent patency. OCT and IVUS were used again to observe the stent endothelial situation; by comparing with histopathologic results, effect of ISA on aneurysm healing and stent endothelialization was analyzed.Results:Lateral common carotid artery aneurysm models in 6 swines were established, and 6 Tubridge FDs were successfully implanted. Compared with IVUS (3 stents, 4 locus), OCT could detect more ISA (6 stents, 14 locus); and the vascular diameter change area (7 locus), aneurysm neck area (4 locus) and the head and tail of FD (3 locus) were the main sites of FD malapposition; average distance between stent wire and vessel wall was (560.14±101.48) μm. At 12 weeks after surgery, DSA showed that 1 patient had a little residual contrast agent at the aneurysm neck (Kamran grading 3), and the remaining 5 had complete aneurysm occlusion (Kamran grading 4). One FD had moderate lumen stenosis, and the other 5 FDs had lumen patency. OCT indicated mostly disappeared acute ISA; ISA proportion decreased to 21.4 % (3/14), including 2 in the aneurysm neck and 1 in the partial stent. Histopathological results showed bare stent woven silk, without obvious endothelial coverage; in one FD with luminal stenosis, intimal hyperplasia was mainly composed of vascular smooth muscle cells.Conclusion:In carotid artery aneurysm model with FD implantation, OCT can detect more ISA than IVUS; most acute ISA have good outcome at 12 th week of follow-up, while severe ISA can cause delayed FD endothelialization and delayed aneurysm occlusion.

Objective To observe the role and mechanism of CO-releasing molecules (CORMs) -2in the injured lung induced by ischmia-reperfusion (IR) of hind limbs of rat.Methods The rat model of lung injury was made by ischemia in hind limbs of rat for two hours and then reperfusion for two hours as well.There were 40 SD rats randomly ( random number) divided into 5 groups ( n =8 ),namely sham ischemia-reperfusion (I/R) group,sham I/R + CORM-2 group,I/R group,I/R + CORM-2 group and I/R + DMSO (Dimethylsulfoxide) group. Rats in sham I/R group underwent laparotomy without infrarenal aorta occlusion.The lung tissue structure,polymorphonuclear neutrophil (PMN) count,wet-to-dry weight ratio (W/D), malondialdehyde (MDA) content, myeloperoxidase (MPO) activity, intercellular adhesion molecule-1 ( ICAM-1 ),nuclear IκBα degradation and NF-κB activity in the lung were measured.Results Compared with the sham I/R group,the number of PMNs in lung,W/D,MDA content,MPOactivity,ICAM-1 and NF-κB activity significantly increased in I/R group,whereas nuclear IκBα decreased (P ＜ 0.01).Compared with the I/R group,the number of PMNs in lung,W/D,MDA content,MPO activity and ICAM-1 significantly decreased in I/R + COMR-2 group ( P ＜ 0.01 ), while nuclear IkBαincreased. Conclusions These data demonstrate that CORM-2 attenuates limb I/R-induced lung injury by inhibiting ICAM-1 protein,NF-κB pathway and the leukocytes sequestration in the lung following limb I/R in rats,suggesting that CORM-2 could be used as one of the most valuable therapeutic agents.