View clinical trials related to Constriction, Pathologic.
Filter by:The overall aim of this work is to assess the relationship between stroke risk and hemodynamic compensation strategies, as measured using a novel 3.0 Tesla MRI protocol, in patients with symptomatic intracranial (IC) steno-occlusive disease. Recent studies have shown high two-year ischemic stroke rates in symptomatic patients with IC arterial stenosis. Therapy for IC stenosis patients includes revascularization with angioplasty, IC stenting, or bypass, however identification of patients most likely to benefit from these more aggressive interventions, rather than medical management alone, has been problematic. Accurate measurements of hemodynamic compromise are likely required to better define stroke risk and guide treatment decisions. Specifically, in IC stenosis patients with compromised cerebral perfusion pressure (CPP), the extent of hemodynamic compromise reflects the autoregulatory capacity of vasculature to increase arterial cerebral blood volume (aCBV) and/or develop collaterals to supplement cerebral blood flow (CBF). The prevalence of CBF collateralization and aCBV autoregulation has been hypothesized to correlate uniquely with stroke risk, however the extent of this correlation has been debated. The critical barrier to stratifying stroke risk rests with a lack of (i) methodology for measuring multiple hemodynamic factors with high specificity and (ii) noninvasive approaches capable of monitoring longitudinal progression of impairment. The investigators have demonstrated the clinical utility of relatively new, noninvasive MRI approaches for assessing cerebrovascular reactivity (CVR), aCBV, and collateral CBF. The investigators hypothesize that stroke risk can be more completely evinced from collective measurements of these parameters. Therefore, the investigators propose to implement a novel, validated hemodynamic MRI protocol to assess tissue-level impairment and compensation strategies in patients with IC stenosis. Using a collective approach combining measurements of collateral CBF, aCBV and CVR in multiple brain regions, in conjunction with a statistical model incorporating the above variables as possible prognostic factors, the investigators will quantify the extent to which two-year stroke risk is associated with hemodynamic compensation mechanisms. The noninvasive and multi-faceted scope of this investigation is intended to expand the diagnostic stroke infrastructure and elucidate new hemodynamic prognostic indicators of stroke in this high-risk population.
Study of platelet activation by severe aortic stenosis and its correction by Transcatheter Aortic Valve Implantation (TAVI)
Cervical stenosis may occur in up to 19% after conization. It is a cause of infertility and amenorrhea. This study will test a new device named DUDA Device ("Dispositivo Uterino para dilatar canal endocervical") placed just after the conization, in order to evaluate the safety, efficacy and quality of life.
The central hypothesis of this study is that TAVR leads to platelet deposition and inflammatory cell activation that can be attenuated by the potent anti-platelet and/or pleiotropic effects of ticagrelor. This single center, prospective randomized trial addresses the following specific aims: 1. To determine whether high-potency ADP receptor blockade reduces measures of platelet activation in patients after TAVR. 2. To determine whether high-potency ADP receptor blockade mitigates the pro-thrombotic inflammatory response observed after TAVR.
The study is aimed at answering the questions; (1) How well do the most commonly used treatments in iSGS work? and (2) What quality-of-life trade-offs are associated with each approach? With the results of this trial, the investigators hope to provide information to iSGS patients: (1) Given my personal characteristics, conditions, and preferences, what should I expect will happen to me? and (2) What are my options, and what are the potential benefits and harms of these options?
The primary objective of the current study is to determine whether Ataciguat (HMR1766) slows progression of valve calcification in patients with moderate calcific aortic valve stenosis. Secondary and tertiary objectives are to determine whether Ataciguat slows progression of aortic valve function, reduces systemic inflammation, and prevents left ventricular dysfunction in patients with moderate calcific aortic valve stenosis.
Fractional flow reserve (FFR) is a pressure-wire-based index that is used during coronary angiography to assess the potential of a coronary stenosis to induce myocardial ischemia. Recent ESC guidelines referred to the usefulness of FFR extensively when noninvasive stress imaging is contraindicated, non-diagnostic, or unavailable. However, FFR requires additional manipulation with maximal and stable hyperemia by intravenous adenosine. More routine use of FFR for all angiographically significant stenoses would add considerable time, cost, and complexity to each PCI procedure and might also increase the risk of catheter-related complications such as coronary dissection and perforation. Although the guideline mentioned that FFR may not be useful in very high grade lesions (angiographically >90%) which always have an FFR <0.80, it have not been revealed yet proper criteria to predict FFR <0.80 obtained by angiographic parameters including degree of stenosis, lesion location and vessel size. It would be valuable to find more precise criteria available by conventional angiography for discrimination of functional stenosis in way to reduce the risk of additional procedure. For the purpose, the investigators will perform FFR in the lesions with significant stenosis (>70% diameter stenosis by visual estimation) and compare the angiographic parameters and FFR values in the study.
This study is designed to monitor the safety and performance of the V8 balloon when used as a postdilatation balloon in self-expanding Transcatheter Aortic Valve Implantation (TAVI) device procedures. The study product is CE marked for balloon aortic valvuloplasty (BAV), and is being investigated for an expanded intended use.
Nocturnal calf cramps is a common complaint in patients with lumbar spinal stenosis. The purpose of this study is to evaluate the effect of botulinum toxin A injection into the gastrocnemius muscle in lumbar spinal stenosis patients receiving conservative therapy. We will compare pain score, insomnia severity, functional ability, patient satisfaction, and neurophysiological variables change using electrical stimulator between control (conservative management for spinal stenosis) and botox group (conservative management for spinal stenosis plus botox injection into the gastrocnemius muscle).
Fluorescence in situ hybridization (FISH) has improved the diagnostic performance of cytology for evaluation of malignant biliary strictures in the US and Europe. The utility of FISH for diagnosis of biliary strictures in Asia is currently unknown. The investigators conducted a prospective study in 2 university hospitals to determine diagnostic performance of FISH for the diagnosis of malignant biliary strictures in Thai patients.