Active clinical trials for "Constriction, Pathologic"

Vertebral artery stenosis (VAS) decreases posterior brain perfusion, causing vertebrobasilar insufficiency (VBI). It is also an important embolic source to the posterior brain. The most frequently involved location is the proximal part of the vessel, including the ostium. Various surgical procedures have been described for the treatment of proximal VAS with symptoms refractory to medical therapy, but all are technically difficult with high operative mortality and morbidity. Endovascular intervention has been described as an alternative to surgery. Balloon angioplasty is limited by elastic recoil and dissection. The restenosis rates reported in the literature varied, as high as 75 %. Stenting offers salvage following unsuccessful balloon angioplasty, and primary stenting have been shown to be safe and effective with lower restenosis rate. Coronary equipments are ideal for ostial VAS, considering the size of the artery and location of the lesion. Recently, Albuquerque et al. reports a relative high restenosis rate in a longer follow-up duration. Restenosis seems to become an important issue regarding the patients' quality of life. However, there is no clinical parameter to predict restenosis of VAS. The purpose of this study is to evaluate the clinical results of our series of symptomatic ostial VAS treated exclusively with tubular balloon expandable coronary stents. We sought to identify predictors of restenosis. This is a clinical observation study. Only chart review and angiographic review will be performed.

The study is a prospective outcome study to evaluate the effectiveness and treatment outcomes of microendoscopic decompressive laminotomy (MEDL) with objective evaluation tools. The patients who fulfill the selection criteria will be enrolled to collect the pre-operative clinical data including demographic data, image studies, and functional evaluation for neurological symptoms and disability. The patient will receive MEDL and post-operative follow-up will be arranged at 1 week, 1 month, 6 months, and 12 months after the operation. All the collected data will be analyzed to evaluate the efficacy and treatment results of MEDL.

Ureteral stents have been widely used in many urological operations. Although there are several reports regarding the effectiveness of long-term ureteral stents for malignancy ureteral obstruction, ureteral stricture and urolithiasis, the experience is limited about the long-term ureteral stents made by Taiwan. The investigators have to propose the 5-year post-market survey report. Though this observation study, The investigators can further understand the clinical safety and effectiveness of placing ureteral stents

Around 1-2% of people are born with a 'bicuspid' aortic valve, with only two cusps instead of the common 'tri-leaflet' valve. People with this valve develop dysfunction of the valve (narrowing or leakage) at a much earlier age. It is also more common for them to develop enlargement of the main blood vessel coming out of the heart, the aorta, and some studies suggest that they are also at higher risk of life-threatening tears in the aortic wall. Current guidelines recommend surgical replacement of the aorta at an earlier stage in these patients. The exact mechanism for the dilatation is not clear, and some studies have suggested greater 'stiffness' in the wall of the aorta. In this study, the investigators propose to 1.) study aortic size, stiffness and flow patterns using MRI in patients with bicuspid and tricuspid valves with a narrowing (aortic stenosis, 2.) measure markers in patients' blood that may be important in the process of expansion, 3.) compare the change in MRI and blood markers at before and 12 months after surgery, in patients who are due to have aortic valve replacement surgery.

Evaluate the feasibility for the on-table evaluation of the renal perfusion by using Syngo Dyna Parenchymal Blood Volume(PBV) Body; Explore the clinical benefits of this application during procedure to help the physician to determine the procedure endpoint.

Change in coronary microcirculation and Fractional Flow Reserve after Transcatheter Aortic Valve Implantation in patients with concomitant coronary artery disease and severe aortic stenosis. Severe aortic stenosis is the most common indication of valvular replacement in developed countries. Stable coronary artery disease (CAD) is frequently associated with severe aortic stenosis in patients treated by Transcatheter Aortic Valvular Implantation (TAVI). Its prognostic impact is not clearly established, and available studies uncommonly used functional assessment of severity from a coronary stenosis to stratify the risk in this situation. Fractional Flow Reserve (FFR) is recommended to guide revascularization by percutaneous coronary intervention (PCI) in clinical practice. Its use is not validated in patients with severe aortic stenosis. Left ventricular hypertrophy induced by aortic obstruction leading to microvascular disorders, and can alter coronary reserve, possibly biasing FFR values. After aortic valvular replacement, a myocardial reverse remodeling is described, generating a decrease in hypertrophy, interstitial oedema, and inflammation. Its effect on coronary microcirculatory reserve is not known. Some studies have shown improvement in coronary reserve immediately after TAVI and this effect seemed to last long after treatment. The aim of the study is to assess the effects of inverse myocardial remodeling on coronary microcirculatory function and its association with FFR values before and after TAVI.

Prospective Observational Single Arm study aimed to assess safety and effectiveness of APERTO OTW DCB in treating stenosis and restenosis of central veins in dialysis patients

The purpose of this postmarket Registry is to assess the standard of care and clinical outcomes of the Direct Flow Medical Transcatheter Aortic Valve System used in clinical routine according to the approved commercial indications. Procedures and assessments required by this registry are generally considered standard of care for Transcatheter Aortic Valve Replacement patients. Evaluation criteria will be the incidence of mortality/morbidity and adverse events clinical performance, and hemodynamic performance of the DEVICE via ultrasound (echo) and angiographic imaging.

Investigate the current situation of carotid stenosis therapy in China. Establish the data bank of carotid stenosis revascularization (CAS and CEA) in China ,in order to get best quality control of the therapy, as well as confirm the standard treatment for carotid stenosis. Understand situation about the adverse events occurs after the revascularization (CAS and CEA), evaluate the health economics .

Narrowing of the main valve which controls blood leaving the heart leads to a marked increase in death. To overcome this narrowing the heart muscle thickens abnormally and contracts more vigorously. However, in doing so, blood flow patterns to the heart muscle change through mechanisms which are incompletely understood. New technology allows such heart valve blockages to be fixed using balloons and metal stents inserted through tubes placed in arteries in the leg. Using sensors placed in these tubes it is possible to make detailed measurements of coronary flow and pressure, and apply new mathematical techniques to allow a better understanding of the detrimental effects that aortic stenosis has on coronary flow, before and after valve surgery.