View clinical trials related to Constriction, Pathologic.
Filter by:In patients with aortic stenosis the valve through which blood is pumped out of the main heart chamber is narrowed. This results in heart muscle working harder to open the valve so blood can circulate around the body. The muscle adapts to the increased pressure load to maintain efficiency. This can cause long-term muscle damage. To predict when this deterioration will require a valve replacement is difficult and untimely operation exposes patients to unnecessary risk. We aim to compare all validated techniques looking at different aspects of heart muscle strain in these patients. These will be a blood sample measuring a specific hormone (BNP) and enzyme (Troponin), a nuclear scan to assess nerve activation, an MRI identifying scarring and an exercise echocardiogram that measures heart muscle response and pressure changes across the valve. Tests will be performed at recruitment and either after one year or after valve replacement, which ever comes first. In comparing these different imaging techniques we aim to identify patients who will benefit from an early operation, those whose muscle is likely to recover back to normal and which patients it is safe to wait longer for the surgery, avoiding unnecessary risk. The results of the study will benefit patients as it will help doctors more accurately assess the timing of valve surgery and improve their prediction of long term heart muscle recovery. It may also increase convenience in clinical management by reducing unnecessary tests and hospital trips. This would translate into cost savings for the NHS.
The purpose of this study is to assess the safety and performance of the 23mm Portico Transcatheter Heart Valve and the TAVI Transapical Delivery System in subjects with severe symptomatic aortic stenosis
The purpose of this study is to examine the neuropsychological effects of transvascular aortic valve implantation (TAVI). Patients undergoing TAVI usually suffer from congestive heart failure and low cardiac output which may limit their cognitive abilities. TAVI results in significant improvements in cardiac function and therefore may improve cognitive functions. However, TAVI may also be associated with stroke and may therefore have a negative impact on cognition. Therefore, in this study the investigators wish to perform a battery of standardized neuropsychological tests before and after TAVI to test the net effects of TAVI on cognitive performance over time. The investigators plan to include all patients planned to have TAVI in the study and to test them before, 3,7, 30 and 360 days post TAVI with a standardized battery of test.
Left main stenosis use to be treated by bypass but with the improvement of angioplasty techniques, an increasing number of patients are submit to left main coronary angioplasty. Consequences of left main intra stent stenosis can be disastrous yet, for the moment, no precise recommendation concerning the follow up of these patients exist. The investigators ought to determine if stress echocardiography can predict left main intra stent stenosis as well (non inferiorly)as control angiography that use to be done.
Background: In a previous study, information verbally presented as relative risk (e.g. "50% less likely") or qualitative risk (e.g. "significantly less likely") resulted in many more people (66%) choosing a surgical procedure for narrowing or artery in the neck than people presented with absolute risk (e.g. "11% versus 5% over 5 years"), annualized risk (e.g. "2% versus 1% per year for 5 years") and event-free survival (e.g. "95% versus 89% over 5 years") (33%). Objectives: The purpose of this study is to determine whether the same observations are true for information that is presented visually as a bar graph. In addition, the investigators also seek to determine whether subjects feel that they understand the information better when presented visually as compared with verbally. Methods: 450 subjects will be approached in the neurology clinic as they are waiting for their office visit. If the subject agrees to participate in this 10 minute study, they will be taken to a quiet room where they will watch a 1 minute video on a laptop. The video will feature an acting physician. The presenter will be the same for all experiment groups. The presenter will describe a hypothetical medical situation in which a narrowing of one of the carotid (neck) arteries is present. The presenter will then describe the risk of a stroke related to that condition if the subject chooses medical therapy versus medical and surgical therapy. The presentation of risk will vary and may be presented in one of 3 different ways including a qualitative description, an absolute risk reduction over a fixed time period, and a relative risk reduction. These three risk groups will be presented either verbally or visually through bar graphs. In the visual subject groups, the presenter will be holding up a graph and remain silent while the graph is shown. The amount of time allotted for the graph on the video will be equal to the amount of time it takes the presenter to say the information in the auditory subject groups. Given that there will be 2 sensory modalities (verbal of visual) and 3 different presentation formats, there will be a total of 6 different videos. After the video is complete, the subject will be asked to complete a 1 page survey which will ask about the patient's age, gender, educational level, reason for the medical visit, and final decision about choice of treatment. The subjects will also answer how well they understood the data by making a mark on a 10 cm horizontal line.
This preliminary study will compare the effectiveness of two-dimensional and three-dimensional echocardiographic measurements of wall thickness and left ventricular mass in patients with Aortic Stenosis
To detect coronary artery disease by both coronary and carotid artery imaging and myocardial perfusion imaging using a new low mechanical index real time system.
The proposed study will investigate the efficacy of the peripheral cutting balloon (PBC) compared to the high pressure balloon in dilating venous stenosis in hemodialysis fistulas. 2. SPECIFIC AIMS Study endpoints will be: Primary Endpoint 1. Primary and assisted patency at 6 months Secondary Endpoints: 1. Procedure effectiveness/residual stenosis 2. Procedure-related complications 3. Primary patency and primary assisted patency 12 months 4. Secondary patency at 6 and 12 months 5. Number/type of secondary interventions.
The purpose of this study is to determine whether suppressing acid production by administration of daily proton pump inhibitors in the early post-operative period will reduce the gastrojejunal anastomosis stricture rate in patients undergoing laparoscopic gastric bypass surgery for morbid obesity.
Pilot study of early versus delayed carotid endarterectomy (CEA) for small to medium-sized ischemic stroke caused by high-grade carotid stenosis.