Active clinical trials for "Constriction, Pathologic"

Balloon angioplasty is used to open up a narrowing that forms in hemodialysis fistula. Two areas of particular problems are the terminal portion of the cephalic vein near the shoulder and the central veins in the chest. Although angioplasty is standard of care the treated narrowed segments of vein mostly renarrow within 3 months requiring retreatment to keep your dialysis access functional. Recently there has been introduction of a new technology called a covered stent graft. Initial studies suggest that placing this device across the area of narrowing leads to dialysis access staying open longer and needing less angioplasty treatments. This study is designed to compare angioplasty (standard of care) versus using a covered stent graft. The investigators will then look at the dialysis records and future fistulograms to see if there is decreased flow through the fistula at 3, 6 and 12 months after the initial procedure.

Among patients admitted with cerebral ischemia (stroke and transitory ischemic attack (TIA)) it is important to reveal the underlying cause of the disease. In special it is important to reveal if carotid artery stenosis is present as such a finding will directly influence on treatment and follow-up. For the diagnosis of carotid artery stenosis due to atherosclerosis ultrasound examinations is the cornerstone, but computer tomography and magnetic resonance imaging may be better in some cases. Development of high quality pocket-sized ultrasound scanners has allowed for semi quantitatively bed-side assessment of the carotid arteries and the heart. The investigators aim to study the feasibility and reliability of bed-side assessment of the carotid arteries by pocket-sized ultrasound scanners in inexperienced hands and the clinical influence of this examination when performed by experienced users. The investigators hypothesize that a significant proportion of this patient population can be clarified bed-side by junior doctors with no need of further imaging procedures for the assessment of the carotid arteries and the heart.

There is evidence that the degenerative changes leading to aortic stenosis are caused by a chronic inflammatory process. Furthermore the development of aortic stenosis is partially dependent on typical cardiovascular risk factors. An inflammatory process as well as those risk factors are amenable for medical therapy. As such the use of statins (HMG CoA reductase inhibitors) would be an appealing concept to reduce both those risks for development of aortic stenosis. Aim of this study is to evaluate the usefulness of statin therapy on the progression of aortic stenosis.

This study aims to estimate if performing a small caliber office hysteroscopic cervical negotiation would succeed to bypass tight markedly stenotic cervix in comparison to blind cervical probing done under general anesthesia. Moreover, the investigators test the impact of drawing a detailed diagram after this procedure on the success of ET in participants with failed mock or actual trials of embryo transfer (ET).

Dialysis patients presenting for angioplasty intervention for graft failure will be randomized to receive either Sirolimus or not receive Sirolimus (standard of care) to assess the time from primary failure or angioplasty intervention to second or next angioplasty intervention or graft failure.

The aim of the study is to value, in patients with chronic kidney disease and hypertension, whether medical therapy plus interventional renal artery revascularization is superior to medical therapy alone for the treatment of hemodynamically significant (>70%) atherosclerotic renal artery stenosis, diagnosed by duplex doppler ultrasonography and confirmed by magnetic resonance angiography, in terms of avoidance of the progression of renal damage, control of hypertension and in reducing the cerebro and cardiovascular complications.

To determine whether recurrent stenosis following carotid endarterectomy could be reduced by pre- and post-operative oral administration of platelet-inhibiting drugs.

Internal carotid artery (ICA) is intended to supply blood to brain. The carotid bulb located upstream of ICA origin is prone to atherosclerosis. This is an accumulation of fat and calcium in the wall forming a plaque that gradually thickens and leads to carotid stenosis (CS), which causes a decrease in blood flow. The risk of CS is stroke caused either by carotid artery thrombosis (occlusion) or by atherosclerotic plaque fragmentation, some components of which may leak into the brain (embolism). When diagnosing CS, an Echo-Doppler is performed to determine bulb and ICA origin obstruction rates. The reference method of quantifying CS is based on hemodynamic criteria that only allow the diagnosis of high grade stenosis thresholds (50%-70%). Below 50%, low-grade stenosis, patient follow-up is limited and could be based on morphological criteria; ultrasound imaging being a reference technique for human body structures morphological assessment, especially vessels. Two methods of CS morphological quantification with Doppler ultrasound currently exist. Calibre reduction at the maximum of stenosis can be measured by relating the smallest luminal diameter to the vessel diameter at stenosis site (ECST method) or to the downstream ICA diameter (NASCET method). As bulb diameter measures ≈1.8 times that of ICA, ECST appears to be more suitable for CS quantification. For high-grade stenosis, morphological quantification performance is impaired due to extensive calcification of large atheromatous plaques. However, it is possible that less calcified nature of low-grade stenosis and the use of a rigorous methodology will allow reproducible assessment in routine practice. This technique has not yet been evaluated, although it is a frequent situation in patient follow-up.

The purpose of this study is to investigate whether preventative placement of a removable oesophageal stent reduces the rate of scar tissue, or stricture formation after removing the precancerous or early cancerous Barrett's mucosa by Endoscopic Mucosal Resection (EMR). The stent will be placed 10-14 days after initial EMR. The stent will then be removed 8 weeks later by repeat Endoscopy. Patients will be followed up weekly following insertion of the oesophageal stent.

To evaluate the clinical benefits and risks of hybrid operating techniques in management of intracranial aneurysms with coexistence of atherosclerotic intracranial arterial stenosis.