Objective To study the mechanism of restenosis of the vein graft and the effect of the grafting injury to the vein graft. Methods One side of the 36 healthy rabbits was randomly chosen as the V-A group, and on the side a 1.5cmlong femoral vein was obtained, and an 0.5-cm-long segment of the obtained femoral vein was separated as the control group. The remaining 1-cm-long femoral vein was inverted and was autogenously implanted into the femoral artery on the same side of the rabbit. The other side of the rabbits was chosen as the V-V group, and on this side a 1-cm-long femoral vein was obtained ex vivo and then was sutured in situ. The vein grafts on both sides were harvested 4 weeks after operation. The specimens from the harvested vein grafts were stained with HE and theelastic fiber Victoria blue for an observation on the histological changes in the walls of the vein grafts, and the specimens were also stained by the immunohistochemistry of the proliferating cell nuclear antigen (PCNA) for an observation on the wall cell proliferation of the vein grafts. The changes in the ultrastructure of the proliferated wall cells of the vein grafts were observed under electron microscope. The two sides of the rabbits were compared. Results The smooth muscle cells of the media developed hyperplasia, but theintima and the media remained unchanged in their thickness (3.50±0.41 μm, 12.23±1.59 μm) in the V-V group, with no difference when compared with the control group (3.40±0.37 μm, 12.14±1.62 μm); however, when compared with the V-A group (25.60±3.21 μm, 21.30±2.47 μm),there was a significant difference in the thickness (Plt;0.01). There were no cells positive for PCNA by the immunohistochemistry examination in the control group. The cells positive for PCNA were found in the intima and the media in both the V-V group and the V-A group; however, the percentageof the cells positive for PCNA in the intima and the media was significantly greater in the V-A group than in the V-V group (16.4%±1.9% and 36.5%±3.7% vs 5.9%±1.3% and 23.4%±3.4%, Plt;0.01). In the V-V group, the endothelial cell could be observed under transmis-sion electron microscope, which was flat and had a processlike villus at its free end, and the endothelial cells were closely arranged andhad hyperplasia of the smooth muscle cells in the media. But in the V-A group,the endothelial cells had an obvious hyperplasia with an irregular shape and a widened space between the cells, and in the intima a great amount of the smooth muscle cells could be observed, which had a broken basement membrane. The smooth muscle cells also had an obvious hyperplasia in the media. The shape and alignment of the endothelial cells in the control group were similar to those in the V-V group, but the hyperplasia of the smooth muscle cells was not observed in the media. Conclusion The grafting injury can cause hyperplasia ofthe vascular wall cells, and if the hemodynamics is changed simultaneously, more serious hyperplasia and cell migration can be observed from the media to the intima, resultingin restenosis of the blood vessels. So, if we can reduce the grafting injury and improve the microcirculation of the vein graft, we may find out the methods ofpreventing restenosis of the vein graft. The animal model of the V-V graftcan help to understand the mechanism of restenosis of the vein graft.
Transcatheter aortic valve replacement has revolutionized the management of aortic stenosis and become the gold standard for the treatment of symptomatic and severe aortic valve stenosis in elderly patients. With the improvement in design and materials, newer generation transcatheter aortic valve prostheses had overcome the limitations of early-generation devices that were susceptible to paravalvular leak, atrioventricular block and vascular complications, to a certain extent. This review provides an update on the latest advances in transcatheter aortic valve prostheses.
OBJECTIVE: To discuss the clinical properties, operative results of thoracic spinal stenosis and factors correlating with prognosis. METHODS: From September 1992 to January 2001, 16 patients who suffered from thoracic spinal stenosis caused by degeneration, ossified ligamentum flavum, diffuse idiopathic hyperostosis and trauma, were decompressed by operation. The operative method was selected according to the compressed position of spinal cord. All patients were followed up 6 months to 9 years. The pain severity, ambulatory status and paraplegia index were compared between before operation and after operation. The correlation between prognosis and ages, the length of stenosis and the duration of disease was studied. RESULTS: The results of Wilcoxon Signed Ranks Test show significant difference in pain severity, ambulatory status and paraplegia index between before operation and after operation (P lt; 0.01). The results of partial correlation analyzing show that only the duration of disease was correlated with paraplegia index (P lt; 0.05). CONCLUSION: Thoracic spinal stenosis frequently develops in the lower-thoracic segments in middle and old aged men. Decompression by operation early can achieve a good clinical result. Duration of disease affects the prognosis.
Objective To evaluate the safety and efficacy of transcatheter aortic valve replacement (TAVR) using the SAPIEN 3 system. MethodsThis was a prospective, multicenter, single arm study in 4 centers in China. The clinical data of 50 patients with high-risk symptomatic severe aortic stenosis who underwent TAVR using the SAPIEN 3 system from June 2017 to June 2019 were analyzed, including 27 males and 23 females aged 76.8±6.1 years. ResultsThe Society of Thoracic Surgeon score was 6.0%±2.8%. Totally, 20.0% of patients had severe bicuspid aortic stenosis. The operation time was 41.8±16.5 min and the hospital stay time was 8.5±5.0 d. At the postoperative 30-day follow-up, no all-cause mortality occurred and the device success rate was 89.5%. Major vascular complications occurred in one (2.0%) patient, stroke in one (2.0%) patient, new pacemaker implantation in one (2.0%) patient, as well as coronary artery obstruction in one (2.0%) patient. There was no moderate or moderate/severe paravalvular leak. The aortic pressure gradient was decreased from 49.2±16.2 mm Hg before the operation to 12.4±4.6 mm Hg at the postoperative 30-day follow-up, and the valvular area was increased from 0.6±0.3 cm2 to 1.3±0.3 cm2 (P<0.01). Moreover, the New York Heart Association classification in 83.7% of the patients was improved during the follow-up. ConclusionThis pre-marketing multicenter study has demonstrated the safety and effectiveness of transfemoral TAVR with the SAPIEN 3 transcatheter valve system in Chinese aortic stenosis patients at high risk for surgery.
In developed nations, aortic stenosis (AS) is the most common valvular heart disease presentation, and its prevalence is increasing due to aging populations. Accurate diagnosis of the disease process and determination of its severity are essential in clinical decision-making. Although current guidelines recommend measuring transvalvular gradients, maximal velocity, and aortic valve area in determining the disease severity, inconsistent grading of disease severity remains a common problem in clinical practice. Recent studies suggest that patients with paradoxical low-flow and/or low-gradient, severe AS are at a more advanced stage of the disease process and have a poorer prognosis. This mode of presentation may lead to an underevaluation of symptoms and inappropriate delay of AVR. Therefore, this challenging clinical situation should be carefully assessed in particular in symptomatic patients and clinical decisions should be tailored individually.
Transcatheter aortic valve replacement (TAVR) has become a common theraputic option for aortic stenosis, but the evidence for precise anatomy for TAVR is accumulating. This paper presents the case of an 71-year-old female patient who had an extremely high risk of coronary obstruction due to both coronary ostia lying too low. The patient underwent TAVR with the help of coronary protection successfully. During the procedure, the patient was protected with wires only for both coronaries. After deployment, angiofluoroscopy suggested that chimney stenting should be applied for left coronary. The whole procedure was unenventful and both coronaries were seen.
ObjectiveTo discuss the clinical classification and treatment protocols of complete duplication of kidney and ureter in children. MethodsBetween March 2000 and February 2015, 106 children with complete duplication of kidney and ureter were treated, and the clinical data were retrospectively analyzed. Of them, there were 11 boys and 95 girls, aged from 1 month to 11 years (mean, 3.5 years); one side was involved in 88 cases and two sides in 18 cases. They were divided into 4 types according to image examinations and clinical presentations:14 patients who needed no special treatment were classified into the first type, 15 patients who underwent reconstruction into the second type, 74 patients who underwent segment removal of renal dysplasia and subtotal excision of abnormal duplicated ureter into the third type, and 3 patients who underwent removal of the whole affected kidney and subtotal excision of whole ureter into the forth type. ResultsThe patients were followed up 2 months to 14 years (median, 23 months). There was no deteriorating case in the first type. There was no complication such as leakage of urine, discomfort over the back and loins, ureterocele, reproductive tract infection, or hematuresis in the other types. The results of white blood cell count, renal function, and electrolyte presented no abnormality. One patient in the second type and 6 patients in the third type had ureteral stump syndrome; 1 patient in the second type and 3 patients in the third type had urinary tract infection; and 3 patients in the second type had mild hydronephrosis after operation. ConclusionIt can obtain good clinical outcome to choose individualized treatment according to clinical classification of complete duplication of kidney and ureter, which can reserve effective renal units as much as possible and improves the patients' quality of life.
Objective To improve the knowledge on dynamic benign central airway stenosis through two typical cases. Methods The clinical features, imaging findings, and bronchial morphologic changes of two cases characterized by dynamic benign central airway stenosis were retrospectively analyzed. The etiologies for the two cases were tracheobronchomalacia (TBM) and excessive dynamic airway collapse (EDAC), respectively. Results Central airway stenosis and reversible airway obstruction were common clinical characteristics for the two cases. However, there were identifiable differences on imaging findings and bronchial morphologic changes between the two cases. Multidetector computed tomography showed sabre-sheath trachea and narrowed trachea in coronal position for TBM, while small sized trachea in exhalation phase and narrowed trachea in sagittal position for EDAC. Bronchoscopy displayed narrowed airway, swelling mucosa, and the absence of annular cartilage for TBM, while crescent airway with membranacea part protruding to lumen in inspiration phase, and the integrity of annular cartilage for EDAC. Conclusion Multidetector computed tomography and bronchoscopy examinations are valid methods to distinguish TBM and EDAC, which are both characterized by dynamic benign central airway stenosis.